Main Page Practice Using Toolkit Applications Hands-On Lesson (C)
## Table of Contents
       Practice Using Toolkit Applications Hands-On Lesson (C)
          Overview
          Note About HTML Links
          References
             Tutorials
             User's Guides
          Recommended Setup
          Kernels Used
          Note About ``Screen Shots'' Included in This Lesson
       BRIEF
          Task Statement
          Steps
          Explanations
       CKBRIEF
          Task Statement
          Steps
          Explanations
       SPACIT
          Task Statement
          Steps
          Explanations
       COMMNT
          Task Statement
          Steps
          Explanations
       TOXFR
          Task Statement
          Steps
          Explanations
       TOBIN
          Task Statement
          Steps
          Explanations
       CHRONOS
          Task Statement
          Steps
          Explanations
       STATES
          Task Statement
          Steps
          Explanations
       SPKDIFF
          Task Statement
          Steps
          Explanations
       FRMDIFF
          Task Statement
          Steps
          Explanations
Top # Practice Using Toolkit Applications Hands-On Lesson (C) May 21, 2018 Top ## Overview In this lesson you will practice using some of the application programs provided in the Toolkit -- ``brief'', ``ckbrief'', ``spacit'', ``commnt'', ``toxfr'', ``tobin'', ``chronos'', ``states'', ``spkdiff'', and ``frmdiff'' -- by completing a series of simple assignments for each of them. Top ## Note About HTML Links The HTML version of this lesson contains links pointing to various HTML documents provided with the Toolkit. All of these links are relative and, in order to function, require this document to be in a certain location in the Toolkit HTML documentation directory tree. In order for the links to be resolved, if not done already by installing the lessons package under the Toolkit's ``doc/html'' directory, create a subdirectory called ``lessons'' under the ``doc/html'' directory of the ``cspice/'' tree and copy this document to that subdirectory before loading it into a Web browser. Top ## References Top ### Tutorials The following SPICE tutorials are referred to by the discussions in this lesson:
       Tutorial              Contents
       --------------------  -----------------------------------
       Intro to Toolkit      lists all Toolkit applications and
                             provides their location within the
                             Toolkit

       Toolkit Applications  provides an overview and a small
                             example for most of the applications
                             covered by this lesson

       SPK                   provides additional information for
                             ``brief'' and ``spacit''

       CK                    provides additional information for
                             ``ckbrief''
These tutorials are available from the NAIF server at JPL:
       http://naif.jpl.nasa.gov/naif/tutorials.html
Top ### User's Guides The Toolkit includes a User's Guide document for each of the application programs provided with the Toolkit. The plain text versions of the User's Guides are located under the ``cspice/doc'' directory in the Toolkit installation tree. These documents have the same names as the application programs with extension ``.ug''. For example, the User's Guide for the ``brief'' program is ``cspice/doc/brief.ug'' All User's Guides are also included in the Toolkit in HTML format. The index page providing links to the HTML User's Guides is accessible using the ``User's Guides'' link on the top level HTML index ``cspice/doc/html/index.html''. Top ## Recommended Setup None of the Toolkit programs used in the this lesson are GUI applications. All of them are either command line programs or interactive programs that use simple textual prompts or menus to get user inputs and directions. For this reason these program must be run from a terminal window on Unix platforms and from a command window on Windows platforms. All of the examples included in this lesson assume that the programs can be run by simply typing their name on the command line. To be able to do that the location of the Toolkit executables directory ``cspice/exe'' must be added to the system's environment variable ``path''. On a UNIX system you can add it using the ``set'' command as follows:
       set path = ($path /my_directory/cspice/exe)
where ``my_directory'' is the name of the directory under which the Toolkit is installed on your computer. On a Windows system you can add it by changing the environment variable ``PATH'' from the ``Advanced'' pane on the ``System Control'' panel to include:
       drive:\my_directory\cspice\exe
where ``drive:\my_directory'' is the name of the directory under which the Toolkit is installed on your computer. Top ## Kernels Used The following kernels are used in this lesson:
       FILE NAME                      TYPE  DESCRIPTION
       ------------------------------ ----  ------------------------
       dii_sc_050112_050703.bc        CK    DII pre-separation CK
       dii_sc_050703_050704.bc        CK    DII post-separation CK
       08110_08152pl_live.bc          CK    Predicted CASSINI CK
       08132_08137ra.bc               CK    Reconstructed CASSINI CK
       di_v17.tf                      FK    DI Frames Kernel
       cas_v40.tf                     FK    CASSINI Frames Kernel
       naif0008.tls                   LSK   Generic LSK
       dii_sclkscet_00008_science.tsc SCLK  DII SCLK
       cas00137.tsc                   SCLK  CASSINI SCLK
       di_finalenc_nav_v3.bsp         SPK   DIF Encounter Opnav SPK
       dif_preenc174_nav_v1.bsp       SPK   DIF Long Radionav SPK
These SPICE kernels are included in the lesson packages available from the NAIF server at JPL:
       ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/Lessons/
All examples in this lesson assume that these kernels are located in the directory from which you will run the programs. If you use kernels supplied in the lesson package, arranged under the ``kernels/<kernel_type>'' directory tree, you can copy them to your current directory by typing this command on your Unix computer:
       % cp [path_to_lesson_dir]/kernels/*/*.* .
or this command on your Windows computer:
       % copy [path_to_lesson_dir]\kernels\*\*.* .
where ``[path_to_lesson_dir]'' is the path to the directory under which the lesson package is installed. Top ## Note About ``Screen Shots'' Included in This Lesson To fit into the 60-character width used for the example ``screen shots'' included in this lesson the application command lines and user responses to application prompts were wrapped at the 60 character boundary (to preserve all required arguments and responses) while the program screen outputs were truncated at the 60 character boundary (to avoid wrapping them into something incomprehensible). In some cases portions of the program outputs were left out and replaced with ``...'' to reduce the overall length of the lesson document. Top # BRIEF Top ## Task Statement Practice running ``brief'', a utility program for summarizing contents of SPK files, to summarize the SPK files:
       dif_preenc174_nav_v1.bsp
       di_finalenc_nav_v3.bsp
Detailed information about the ``brief'' interface is provided in the program's User's Guide (brief.ug) and the usage message displayed by the program. Top ## Steps `1.` Run ``brief'' to see usage (help) display. `2.` Run ``brief'' to generate the basic summary of the SPK file ``di_finalenc_nav_v3.bsp''. `3.` Run ``brief'' to generate a summary of ``di_finalenc_nav_v3.bsp'' in tabular format. `4.` Run ``brief'' to generate a tabular summary of ``di_finalenc_nav_v3.bsp'' including centers of motion. `5.` Run ``brief'' to generate a tabular summary for the ``combined'' ephemeris data provided by both SPK files, ``di_finalenc_nav_v3.bsp'' and ``dif_preenc174_nav_v1.bsp''. Top ## Explanations `1.` Typing ``brief'' by itself displays a page long usage information explaining the command line syntax and all available command line options:
                % brief
                Brief.  Version: 2.3.1        (SPICE Toolkit N0061)

                Usage:

                   brief [-option] file [file ...]

                ...
`` or with the ``-h'' option (even when files names and/or other options are also present):
                % brief -h
                ...
`2.` To generate the basic summary for a single SPK file ``brief' needs to be supplied with only one item on the command line -- the name of the SPK file of interest:
                % brief di_finalenc_nav_v3.bsp
                Brief.  Version: 2.3.1        (SPICE Toolkit N0061)

                Summary for: di_finalenc_nav_v3.bsp

                Body: DEEP IMPACT IMPACTOR SPACECRAFT (-70)
                      Start of Interval (ET)              End of Interval (E
                      --------------------------------    ------------------
                      2005 JUL 03 06:16:04.184            2005 JUL 04 05:46:

                Body: DEEP IMPACT FLYBY SPACECRAFT (-140)
                      Start of Interval (ET)              End of Interval (E
                      --------------------------------    ------------------
                      2005 JUL 03 06:16:04.184            2005 JUL 05 05:45:

                Body: TEMPEL 1 (1000093)
                      Start of Interval (ET)              End of Interval (E
                      --------------------------------    ------------------
                      2005 JUL 03 06:16:04.184            2005 JUL 05 05:46:
`` As seen in the output this SPK contains data for both DI spacecraft and the mission's primary target, comet TEMPEL 1, for the period starting shortly after the separation and ending about an hour after the impact. `` It is important to point out that in this report, as in all other summary reports generated by ``brief'', the coverage boundaries are shown as Ephemeris Time rather than UTC. `` Also note that since the coverages of the three bodies differ slightly the output contains three separate tables with the name and ID of each body provided in the table header. While this basic format works well in some cases, the tabular format discussed in the next step is easier to read. `3.` To generate summary in the tabular format the ``-t'' option must be provided on the command line:
                % brief di_finalenc_nav_v3.bsp -t
                Brief.  Version: 2.3.1        (SPICE Toolkit N0061)

                Summary for: di_finalenc_nav_v3.bsp

                Bodies                               Start of Interval (ET)
                -------                              -----------------------
                -70 DEEP IMPACT IMPACTOR SPACECRAFT  2005 JUL 03 06:16:04.18
                -140 DEEP IMPACT FLYBY SPACECRAFT    2005 JUL 03 06:16:04.18
                1000093 TEMPEL 1                     2005 JUL 03 06:16:04.18
`` Unlike in the basic report all of the bodies are now listed in one table with their names/IDs given in the left column. `` Note that the location of the ``-t'' option on the command line is not significant. It and any other command line option can be specified before, after, or even in between the SPK file name(s). `4.` To generate a tabular summary including centers of motion for each of the bodies the ``-c'' option must be provided on the command line (``-t'' must be provided as well because the summary requested on this step should be in the tabular format):
                % brief di_finalenc_nav_v3.bsp -t -c
                Brief.  Version: 2.3.1        (SPICE Toolkit N0061)

                Summary for: di_finalenc_nav_v3.bsp

                Bodies
                -------
                -70 DEEP IMPACT IMPACTOR SPACECRAFT w.r.t. 1000093 TEMPEL 1
                -140 DEEP IMPACT FLYBY SPACECRAFT w.r.t. 1000093 TEMPEL 1
                1000093 TEMPEL 1 w.r.t. 10 SUN
`` Note that now ``body - center of motion'' pairs appear in the left column of the table. If an SPK contains segments in which data for the same body are provided with respect to different centers, the table will contain a separate line for each pair. More than one line for a pair will be included if the coverage for that pair contains gaps. `` Generating a summary that shows centers of motion is important in many cases. One such case is when an SPK contains data only for the spacecraft. Determining the center(s) of motion of the spacecraft data is the first step in finding and loading additional SPKs that provide data for this(these) centers relative to the Solar System Barycenter so that an application could compute the spacecraft states corrected for light time and stellar aberration. `5.` To generate a tabular summary for the ``combined'' ephemeris data provided by two or more SPK files the ``-a'' option must be provided on the command line in addition to the names of these files (``-t'' must also be provided because the summary requested in this step should be in the tabular format):
                % brief di_finalenc_nav_v3.bsp dif_preenc174_nav_v1.bsp -t
                -a

                Brief.  Version: 2.3.1        (SPICE Toolkit N0061)

                Summary for all files.

                Bodies                               Start of Interval (ET)
                -------                              -----------------------
                -70 DEEP IMPACT IMPACTOR SPACECRAFT  2005 JUL 03 06:16:04.18
                -140 DEEP IMPACT FLYBY SPACECRAFT    2005 JAN 12 19:23:32.06
                1 MERCURY BARYCENTER                 2005 JAN 12 19:23:32.06
                2 VENUS BARYCENTER                               Same covera
                ...
                499 MARS                                         Same covera
                1000004 BOETHIN                      2005 MAY 09 00:00:00.00
                1000093 TEMPEL 1                     2005 JAN 12 19:23:32.06
`` Note that the summary indicates that it is for ``all files'' and that the coverages for all bodies from both files are listed in one table. Also, note that the merge of the coverages for the same body provided by all SPKs given to ``brief'' is included in a single record for that body. `` This type of report is very useful when one needs to find out the totality of the SPK data that would be available to an application when it loads a given set of SPK files, especially if the set includes tens or even hundreds of files. Top # CKBRIEF Top ## Task Statement Practice running ``ckbrief'', a utility program for summarizing contents of CK files, to summarize the CK files:
       dii_sc_050112_050703.bc
       dii_sc_050703_050704.bc
Use these FK, LSK, and SCLK files when needed to complete the task steps:
       di_v17.tf
       naif0008.tls
       dii_sclkscet_00008_science.tsc
Detailed information about the ``ckbrief'' interface is provided in the program's User's Guide (ckbrief.ug) and the usage message displayed by the program. Top ## Steps `1.` Run ``ckbrief'' to see usage (help) display. `2.` Run ``ckbrief'' to generate the basic summary for the ``dii_sc_050703_050704.bc'' CK file without use of additional kernels. `3.` Run ``ckbrief'' to generate the basic summary for ``dii_sc_050703_050704.bc'' with times displayed as Ephemeris Times (ETs). `4.` Run ``ckbrief'' to generate the basic summary for ``dii_sc_050703_050704.bc'' with times displayed as UTCs. `5.` Run ``ckbrief'' to generate the basic summary for ``dii_sc_050703_050704.bc'' with times displayed as SCLKs. `6.` Run ``ckbrief'' to generate a tabular summary for ``dii_sc_050703_050704.bc'' with times displayed as UTCs. `7.` Run ``ckbrief'' to generate an interpolation interval summary for ``dii_sc_050703_050704.bc'' with times displayed as UTCs. `8.` Run ``ckbrief'' to generate the basic summary for ``dii_sc_050703_050704.bc'' and ``dii_sc_050112_050703.bc'' with times displayed as UTCs. `9.` Run ``ckbrief'' to generate the basic summary for ``dii_sc_050703_050704.bc'' and ``dii_sc_050112_050703.bc'' with times displayed as UTCs and the names or IDs of the frames, relative to which the orientation is given, included in the report. Top ## Explanations `1.` Typing ``ckbrief'' by itself displays a page long usage information (help) explaining the command line syntax and all available command line options:
                % ckbrief

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                     CKBRIEF is a command line program that allows you to ea
                     the pointing (orientation) data coverage of one or more
                     files. ``Coverage'' is used in the sense of specifying
                     for which orientation data are available.

                ...
`` or with the ``-h'' option:
                % ckbrief -h
                ...
`2.` When ``ckbrief'' is provided with only the name(s) of the CK files it generates the basic summary that does not include coverage times:
                % ckbrief dii_sc_050703_050704.bc

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin ET        Interval End ET          AV
                  ------------------------ ------------------------ ---
                  NEED LSK AND SCLK FILES  NEED LSK AND SCLK FILES  Y
`` Instead, the ``NEED LSK AND SCLK FILES'' phrase is displayed in the begin and end time columns reminding the user that the encoded SCLK time tags stored internally in the CK files cannot be converted to any other time system without LSK and SCLK data. The program can display the coverage as encoded SCLKs if the ``-dpsclk'' option is given:
                % ckbrief dii_sc_050703_050704.bc -dpsclk

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin TICKS     Interval End TICKS       AV
                  ------------------------ ------------------------ ---
                     44452501808.             44474333491.          Y
`` but these encoded SCLK times are, in general, of very little use because they cannot be easily related to any other, more meaningful time systems. `3.` To generate the basic summary with times displayed as ETs the names of an LSK file and an SCLK file containing data for the clock with which the data in the CK is tagged must be provided on ``ckbrief''s command line in addition to the name of the CK file to be summarized:
                % ckbrief dii_sc_050703_050704.bc naif0008.tls dii_sclkscet_
                00008_science.tsc

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin ET        Interval End ET          AV
                  ------------------------ ------------------------ ---
                  2005-JUL-03 06:04:07.362 2005-JUL-04 05:45:28.172 Y
`` Note that the times are displayed as ETs, as indicated by the table column headers, to make the ``ckbrief'' basic output similar to that of the ``brief'' program. The last column in the table indicates whether the CK data for this ID include angular rates. If this CK contained data for two different structures, the output would have included two separate tables, one for each of the structures. `4.` To generate the basic summary with times displayed as UTCs the ``-utc'' option must be specified on ``ckbrief''s command line in addition to the names of the CK, LSK, and SCLK files:
                % ckbrief dii_sc_050703_050704.bc naif0008.tls dii_sclkscet_
                00008_science.tsc -utc

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV
                  ------------------------ ------------------------ ---
                  2005-JUL-03 06:03:03.177 2005-JUL-04 05:44:23.988 Y
`` The column headings is this report indicate that the times are UTCs. `` Note that the location of the ``-utc'' option on the command line is not significant. It and any other command line options can be specified before, after, or even in between the file name(s). `5.` To generate the basic summary with times displayed as SCLKs the ``-sclk'' option must be specified on ``ckbrief''s command line in addition to the names of the CK, LSK, and SCLK files:
                % ckbrief dii_sc_050703_050704.bc naif0008.tls dii_sclkscet_
                00008_science.tsc -sclk

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin SCLK      Interval End SCLK        AV
                  ------------------------ ------------------------ ---
                  1/0173642585.048         1/0173727865.051         Y
`` The column headings is this report indicate that the times are SCLKs. `6.` To generate the tabular summary with times displayed as UTCs the ``-t'' option must be specified on ``ckbrief''s command line in addition to the names of the CK, LSK, and SCLK files and the ``-utc'' option:
                % ckbrief dii_sc_050703_050704.bc naif0008.tls dii_sclkscet_
                00008_science.tsc -utc -t

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050703_050704.bc

                Objects  Interval Begin UTC       Interval End UTC         A
                -------- ------------------------ ------------------------ -
                -70000   2005-JUL-03 06:03:03.177 2005-JUL-04 05:44:23.988 Y
`` In the tabular summary the ID of the structure is shown in the left column of the table rather than in the table header. `` While for this particular CK file containing data for only one structure the tabular summary is not necessarily better than the basic summary, the tabular format is more desirable for CK files that contain data for many structures because it makes ``ckbrief''s report more compact and easier to read. `7.` To generate the interpolation interval summary report with times displayed as UTCs the ``-dump'' option must be specified on ``ckbrief''s command line in addition to the names of the CK, LSK, and SCLK files and the ``-utc'' option:
                % ckbrief dii_sc_050703_050704.bc naif0008.tls dii_sclkscet_
                00008_science.tsc -utc -dump

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050703_050704.bc

                Segment No.: 1

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV
                  ------------------------ ------------------------ ---
                  2005-JUL-03 06:03:03.177 2005-JUL-03 06:55:51.207 Y
                  2005-JUL-03 06:57:03.208 2005-JUL-03 07:55:51.241 Y
                  ...
                  2005-JUL-04 03:51:59.913 2005-JUL-04 04:39:27.940 Y
                  2005-JUL-04 04:40:31.941 2005-JUL-04 05:44:23.988 Y
`` This type of report is crucial in determining whether a CK file really provides data for a time of interest. Any other, non ``-dump'' report generated by ``ckbrief'' uses only the coverage information from the CK segment descriptors and does not provide visibility of the gaps that may exist in the coverages given in those descriptors. `` Note that this type of report contains a separate table for each of the CK file segments, with the segment number in the file shown before the table header. `8.` To generate the basic summary report with UTC times for more than one CK file the names of all CK files to be summarized should be specified on ``ckbrief''s command line along with the names of the LSK and SCLK files and the ``-utc'' option:
                % ckbrief dii_sc_050112_050703.bc dii_sc_050703_050704.bc na
                if0008.tls dii_sclkscet_00008_science.tsc -utc

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050112_050703.bc

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV
                  ------------------------ ------------------------ ---
                  2005-JAN-12 19:25:45.675 2005-JUL-03 05:59:58.281 Y

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV
                  ------------------------ ------------------------ ---
                  2005-JUL-03 06:03:03.177 2005-JUL-04 05:44:23.988 Y
`` Note that the summary for each of the CK files is given in a separate table. `9.` To generate the basic summary report with UTC times, including the names or IDs of the frames relative to which the orientation is given, the ``-rel'' option must be specified on ``ckbrief''s command line in addition to the names of the CK, LSK and SCLK files and the ``-utc'' option:
                % ckbrief dii_sc_050112_050703.bc dii_sc_050703_050704.bc na
                if0008.tls dii_sclkscet_00008_science.tsc -utc -rel

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050112_050703.bc

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV  Rela
                  ------------------------ ------------------------ --- ----
                  2005-JAN-12 19:25:45.675 2005-JUL-03 05:59:58.281 Y   -140

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV  Rela
                  ------------------------ ------------------------ --- ----
                  2005-JUL-03 06:03:03.177 2005-JUL-04 05:44:23.988 Y   J200
`` Note that the tables in this report include an additional column, ``Relative to FRAME,'' providing either the name or the ID of the reference frame relative to which the orientation for a particular structure is given in the CK segments. ``ckbrief'' displays the frame ID when it cannot map it to the frame name, for example when a frame is not one of the frames built into the Toolkit. If an FK file defining this frame is available, it can be added to the ``ckbrief'' command line to make ``ckbrief'' load the FK and map the frame ID to the frame name using the loaded frame definition:
                % ckbrief dii_sc_050112_050703.bc dii_sc_050703_050704.bc na
                if0008.tls dii_sclkscet_00008_science.tsc di_v17.tf -utc
                -rel

                CKBRIEF Version: 3.2.0, 2006-11-02. SPICE Toolkit Version: N

                Summary for: dii_sc_050112_050703.bc

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV  Rela
                  ------------------------ ------------------------ --- ----
                  2005-JAN-12 19:25:45.675 2005-JUL-03 05:59:58.281 Y   DIF_

                Summary for: dii_sc_050703_050704.bc

                Object:  -70000
                  Interval Begin UTC       Interval End UTC         AV  Rela
                  ------------------------ ------------------------ --- ----
                  2005-JUL-03 06:03:03.177 2005-JUL-04 05:44:23.988 Y   J200
Top # SPACIT Top ## Task Statement Practice running ``spacit'', an interactive utility program for converting, summarizing contents of, and viewing internal comments in SPICE binary kernels, to summarize these SPK and CK files:
       dif_preenc174_nav_v1.bsp
       dii_sc_050703_050704.bc
Use these LSK and SCLK files when needed to complete the task steps:
       naif0008.tls
       dii_sclkscet_00008_science.tsc
Detailed information about the ``spacit'' interface is provided in the program's User's Guide (spacit.ug). Top ## Steps `1.` Run ``spacit'' to generate a summary for the entire SPK file ``dif_preenc174_nav_v1.bsp''. `2.` Run ``spacit'' to generate a summary for the entire CK file ``dii_sc_050703_050704.bc''. Top ## Explanations `1.` To generate a summary for an entire SPK file the ``Summarize binary file'' option from the ``SPACIT Options'' menu should be picked by entering the letter ``s'' in response to the ``Option:'' prompt. Then the names of the SPK and LSK files should be entered in response to the the ``Binary file:'' and ``Leapseconds file:'' prompts. Finally the ``Summarize entire file'' option from the ``SPK Summary Options'' menu should be picked by entering the letter ``f'' in response to the ``Option:'' prompt:
                % spacit

                    Welcome to SPACIT Version: 7.1.1
                          (Spice Toolkit N0061)

                         SPACIT Options

                   ( Q ) Quit.
                   ( L ) Log SPACIT output to a file.
                   ( T ) Convert transfer file to binary file.
                   ( B ) Convert binary file to transfer file.
                   ( S ) Summarize binary file.
                   ( R ) Read comment area of binary file.

                   Option: s

                   Binary file     : dif_preenc174_nav_v1.bsp
                   Leapseconds file: naif0008.tls

                   Loading the Leapseconds kernel file. Please wait ...

                         SPK Summary Options

                   ( Q ) Quit, returning to main menu.

                   ( F ) Summarize entire file.
                   ( B ) Summarize by NAIF body ID code.
                   ( T ) Summarize by time interval.

                   Option: f

                ************************************************************

                Summary for SPK file: dif_preenc174_nav_v1.bsp
                Leapseconds File    : naif0008.tls
                Summary Type        : Entire File

                ------------------------------------------------------------
                   Segment ID     : pfile_od004-radio.nio
                   Target Body    : Body -140, DEEP IMPACT FLYBY SPACECRAFT
                   Center Body    : Body 10, SUN
                   Reference frame: Frame 1, J2000
                   SPK Data Type  : Type 1
                      Description : Modified Difference Array
                   UTC Start Time : 2005 JAN 15 16:47:07.324
                   UTC Stop Time  : 2005 JAN 22 04:00:00.000
                   ET Start Time  : 2005 JAN 15 16:48:11.507
                   ET Stop time   : 2005 JAN 22 04:01:04.184
                ------------------------------------------------------------

                ...

                ------------------------------------------------------------
                   Segment ID     : DE-0405LE-0405
                   Target Body    : Body 1, MERCURY BARYCENTER
                   Center Body    : Body 0, SOLAR SYSTEM BARYCENTER
                   Reference frame: Frame 1, J2000
                   SPK Data Type  : Type 2
                      Description : Fixed Width, Fixed Order Chebyshev Polyn
                   UTC Start Time : 2005 JAN 12 19:22:27.884
                   UTC Stop Time  : 2009 JAN 15 00:03:54.816
                   ET Start Time  : 2005 JAN 12 19:23:32.068
                   ET Stop time   : 2009 JAN 15 00:05:00.000
                ------------------------------------------------------------

                ************************************************************

                ...
`` To quit ``spacit'' after displaying the summary the letter ``q'' should be entered twice in response to the ``Option:'' prompt. `` Note that ``spacit'', unlike ``brief'', does not provide much flexibility in formating the SPK summary output. On the other hand its simple segment-by-segment report contains all segment descriptor details for each of the segments. The segment reports include the body, center, segment ID string, reference frame name and ID, SPK data type and its description, and the coverage boundaries shown as ETs and UTCs. `` Knowing this ``extra'' information, more than provided by ``brief'', may be essential in some cases. For example, the segment ID string may identify the planetary ephemeris version or the producer of the data (note ``DE-0405LE-0405'' in the blocks for the planetary ephemerides segments). Knowing the reference frame may be important to determine if additional kernels providing orientation for this frame have to be loaded together with the SPK in order for the SPK to be used. `2.` To generate a summary for an entire CK file the ``Summarize binary file'' option from the ``SPACIT Options'' menu should be picked by entering the letter ``s'' in response to the ``Option:'' prompt. Then the names of the CK, LSK, and SCLK files should be entered in response to the ``Binary file:'', ``Leapseconds file:'', and ``SCLK file:'' prompts. Finally the ``Summarize entire file'' option from the ``CK Summary Options'' menu should be picked by entering the letter ``f'' in response to the ``Option:'' prompt:
                % spacit

                    Welcome to SPACIT Version: 7.1.1
                          (Spice Toolkit N0061)

                         SPACIT Options

                   ( Q ) Quit.
                   ( L ) Log SPACIT output to a file.
                   ( T ) Convert transfer file to binary file.
                   ( B ) Convert binary file to transfer file.
                   ( S ) Summarize binary file.
                   ( R ) Read comment area of binary file.

                   Option: s

                   Binary file     : dii_sc_050703_050704.bc
                   Leapseconds file: naif0008.tls
                   SCLK file       : dii_sclkscet_00008_science.tsc

                   Loading the Leapseconds kernel file. Please wait ...
                   Loading the SCLK kernel file. Please wait ...

                         CK Summary Options

                   ( Q ) Quit, returning to main menu.

                   ( F ) Summarize entire file.
                   ( I ) Summarize by NAIF instrument ID code.
                   ( U ) Summarize by UTC time interval.
                   ( S ) Summarize by SCLK time interval.

                   Option: f

                ************************************************************

                Summary for CK file: dii_sc_050703_050704.bc
                Leapseconds File   : naif0008.tls
                SCLK File          : dii_sclkscet_00008_science
                Summary Type       : Entire File

                ------------------------------------------------------------
                   Segment ID     : DII TELEMETRED ATTITUDE AND RATE
                   Instrument Code: -70000
                   Spacecraft     : Body -70, DEEP IMPACT IMPACTOR SPACECRAF
                   Reference Frame: Frame 1, J2000
                   CK Data Type   : Type 3
                      Description : Continuous Pointing: Linear Interpolatio
                   Available Data : Pointing and Angular Velocity
                   UTC Start Time : 2005 JUL 03 06:03:03.178
                   UTC Stop Time  : 2005 JUL 04 05:44:23.989
                   SCLK Start Time: 1/0173642585.048
                   SCLK Stop Time : 1/0173727865.051
                ------------------------------------------------------------

                ************************************************************

                ...
`` To quit ``spacit'' after displaying the summary ``q'' should be entered twice in response to the ``Option:'' prompt. `` Note that ``spacit'', unlike ``ckbrief'', does not provide much flexibility in formating the CK summary output. On the other hand its simple segment-by-segment report contains all segment descriptor details for each of the segments. The segment reports include the CK ID, reference frame, coverage, segment ID string, name and ID of the spacecraft to which this CK ID is related, and the CK data type and its description. `` Knowing this ``extra'' information, more than provided by ``ckbrief'', may be essential in some cases. For example, the segment ID string may contain a concise description of the data (note ``DII TELEMETRED ATTITUDE AND RATE'' for the only segment in this CK file). Knowing the CK data type may suggest the best approach to access the data. For example, Type 1 CK files containing discrete orientation and rarely produced these days should be accessed using the middle level CK readers CKGP/CKGPAV with a non-zero tolerance because the higher level interface PXFORM/SXFORM will not be able to read them using zero tolerance. Top # COMMNT Top ## Task Statement Practice running ``commnt'', a utility program for accessing and manipulating internal comments in SPICE binary kernels, to view and extract comments from this SPK file:
       dif_preenc174_nav_v1.bsp
Detailed information about the ``commnt'' interface is provided in the program's User's Guide (commnt.ug). Top ## Steps `1.` Run ``commnt'' in command-line mode to view internal comments included in the ``dif_preenc174_nav_v1.bsp'' SPK file. `2.` Run ``commnt'' in command-line mode to extract to a text file the internal comments included in the ``dif_preenc174_nav_v1.bsp'' SPK file. `3.` Run ``commnt'' in interactive mode to view internal comments included in the ``dif_preenc174_nav_v1.bsp'' SPK file. Top ## Explanations `1.` To view comments included in a binary SPICE kernel by running ``commnt'' in command-line mode the ``-r'' option followed by the kernel name must be provided on ``commnt''s command line:
                % commnt -r dif_preenc174_nav_v1.bsp

                \beginlabel
                PDS_VERSION_ID               = PDS3
                RECORD_TYPE                  = FIXED_LENGTH

                ...

                NOTE                         = "See comments in the file for
                OBJECT                       = SPICE_KERNEL
                  INTERCHANGE_FORMAT         = BINARY
                  KERNEL_TYPE                = EPHEMERIS
                  DESCRIPTION                = "DIF SPICE SP-Kernel file con
                spacecraft trajectory reconstructed from radio tracking data
                planetary ephemerides and ephemerides for the DI mission tar
                DI Navigation Team, JPL, covering the whole mission. "
                END_OBJECT                   = SPICE_KERNEL
                \endlabel

                DIF SPK file, Complete Mission, Last Pre-Encounter Solution
                ============================================================

                     Created by Boris Semenov, NAIF/JPL, September 20, 2005
                     files produced by the Deep Impact (DI) Navigation (NAV)
                     during mission operations.

                Objects in the Ephemeris
                --------------------------------------------------------

                     This file contains ephemeris data for Deep Impact Flyby
                     spacecraft (NAIF ID -140), DI primary mission target co
                     1 (NAIF ID 1000093), DI extended mission opportunity ta
                     Boethin (NAIF ID 1000004), Sun, and planets and planet
                     barycenters.

                ...

                     The spacecraft trajectory segment boundary discontinuit
                     this file are:

                     #
                     # Summary of discontinuities at segment boundaries for
                     # SPK file dif_preenc174_nav_v1.bsp:
                     #
                     #  BOUNDARY TIME (UTC)   DOWNTRK INPLANE  NORMAL
                     #----------------------- ------- ------- -------
                     2005-01-22T04:00:00.000  -0.030   0.106   0.102
                     2005-02-12T00:00:00.000  -0.118   0.113   0.519
                     2005-05-06T00:00:00.000  -0.069  -0.025   0.274
                     2005-06-01T00:00:00.000   0.139   0.066  -0.380
                     2005-07-07T00:00:00.000  51.862  43.397  40.628
`` Ideally all SPICE kernels should contain extensive internal comments describing data origin, data producer, coverage, etc. This is usually more true for the files that are a part of a mission's SPICE archive than for the kernels generated during operations but even ``ops'' kernels sometimes include very lengthy multi-page comments. Since ``commnt'' prints all of the comments to the screen at once, users may find it desirable to pipe ``commnt''s output through ``more'' or a similar utility to be able to read the displayed text starting from the top:
                % commnt -r dif_preenc174_nav_v1.bsp | more

                \beginlabel
                PDS_VERSION_ID               = PDS3
                RECORD_TYPE                  = FIXED_LENGTH
                RECORD_BYTES                 = 1024
                ^SPICE_KERNEL                = "dif_preenc174_nav_v1.bsp"
                MISSION_NAME                 = "DEEP IMPACT"
                SPACECRAFT_NAME              = "DEEP IMPACT FLYBY SPACECRAFT
                DATA_SET_ID                  = "DI-C-SPICE-6-V1.0"
                KERNEL_TYPE_ID               = SPK
                PRODUCT_ID                   = "dif_preenc174_nav_v1.bsp"
                PRODUCT_CREATION_TIME        = 2006-03-01T14:13:15
                PRODUCER_ID                  = "DI NAV/JPL"
                MISSION_PHASE_NAME           = {
                                               "9P CRUISE",
                                               "9P ENCOUNTER",
                                               "9P POST-ENCOUNTER CRUISE"
                                               }
                PRODUCT_VERSION_TYPE         = ACTUAL
                PLATFORM_OR_MOUNTING_NAME    = "N/A"
                START_TIME                   = 2005-01-12T19:22:28
                STOP_TIME                    = 2009-01-15T00:03:55
                --More--
`` Another possibility is to extract comments into a text file and then examine the file using a text editor or a file contents viewing utility run from a terminal or command window. `2.` To extract comments included in a binary SPICE kernel by running ``commnt'' in command-line mode the ``-e'' option followed by two file names -- the kernel file name and the name of a text file into which the comments are to be written -- must be provided on ``commnt''s command line:
                % commnt -e dif_preenc174_nav_v1.bsp comments.txt

                % more comments.txt
                \beginlabel
                PDS_VERSION_ID               = PDS3
                RECORD_TYPE                  = FIXED_LENGTH
                RECORD_BYTES                 = 1024
                ^SPICE_KERNEL                = "dif_preenc174_nav_v1.bsp"
                MISSION_NAME                 = "DEEP IMPACT"
                SPACECRAFT_NAME              = "DEEP IMPACT FLYBY SPACECRAFT
                DATA_SET_ID                  = "DI-C-SPICE-6-V1.0"
                KERNEL_TYPE_ID               = SPK
                PRODUCT_ID                   = "dif_preenc174_nav_v1.bsp"
                PRODUCT_CREATION_TIME        = 2006-03-01T14:13:15
                PRODUCER_ID                  = "DI NAV/JPL"
                MISSION_PHASE_NAME           = {
                                               "9P CRUISE",
                                               "9P ENCOUNTER",
                                               "9P POST-ENCOUNTER CRUISE"
                                               }
                PRODUCT_VERSION_TYPE         = ACTUAL
                PLATFORM_OR_MOUNTING_NAME    = "N/A"
                START_TIME                   = 2005-01-12T19:22:28
                STOP_TIME                    = 2009-01-15T00:03:55
                --More--
`` If a text file with the specified name already exists ``commnt'' will not overwrite it and will stop with an error message instead. `3.` To view comments included in a binary SPICE kernel by running ``commnt'' in interactive mode, invoke ``commnt'' without any command line arguments, pick the ``Read the comments in a binary file'' option from the ``COMMNT Options'' menu by entering the ``r'' letter in response to the ``Option:'' prompt, then enter the kernel file name in response to the ``Filename?'' prompt:
                % commnt

                   Welcome to COMMNT Version: 6.0.1
                        (Spice Toolkit N0061)

                         COMMNT Options

                   ( Q ) Quit.
                   ( A ) Add comments to a binary file.
                   ( R ) Read the comments in a binary file.
                   ( E ) Extract comments from a binary file.
                   ( D ) Delete the comments in a binary file.

                   Option: r

                Enter the name of the binary file.

                Filename? dif_preenc174_nav_v1.bsp

                Reading the comment area of the SPK file.

                File: dif_preenc174_nav_v1.bsp

                \beginlabel
                PDS_VERSION_ID               = PDS3
                RECORD_TYPE                  = FIXED_LENGTH

                ...

                     The spacecraft trajectory segment boundary discontinuit
                     this file are:

                     #
                     # Summary of discontinuities at segment boundaries for
                     # SPK file dif_preenc174_nav_v1.bsp:
                     #
                     #  BOUNDARY TIME (UTC)   DOWNTRK INPLANE  NORMAL
                     #----------------------- ------- ------- -------
                     2005-01-22T04:00:00.000  -0.030   0.106   0.102
                     2005-02-12T00:00:00.000  -0.118   0.113   0.519
                     2005-05-06T00:00:00.000  -0.069  -0.025   0.274
                     2005-06-01T00:00:00.000   0.139   0.066  -0.380
                     2005-07-07T00:00:00.000  51.862  43.397  40.628

                The comments were successfully read.
                         COMMNT Options

                   ( Q ) Quit.
                   ( A ) Add comments to a binary file.
                   ( R ) Read the comments in a binary file.
                   ( E ) Extract comments from a binary file.
                   ( D ) Delete the comments in a binary file.

                   Option:
`` To quit ``commnt'' after displaying the summary ``q'' must be entered in response to the ``Option:'' prompt. Top # TOXFR Top ## Task Statement Practice running ``toxfr'', a command line utility program for converting SPICE binary kernels to transfer format, to convert this SPK file:
       dif_preenc174_nav_v1.bsp
Detailed information about the ``toxfr'' interface is provided in the program's User's Guide (toxfr.ug). Top ## Steps `1.` Run ``toxfr'' to see usage (help) display. `2.` Run ``toxfr'' to convert the SPK file ``dif_preenc174_nav_v1.bsp'' to transfer format without explicitly specifying the output transfer file name. `3.` Run ``toxfr'' to convert the SPK file ``dif_preenc174_nav_v1.bsp'' to transfer format with explicitly specifying the output transfer file name. Top ## Explanations `1.` Typing ``toxfr'' by itself displays a short usage message explaining the command line syntax:
               % toxfr

               ============================================================

               Toolkit version: N0061

               SPICE(USAGEERROR)

               Usage: toxfr file.b* [file.x*]

               A traceback follows.  The name of the highest level module i
               TOXFR

               ============================================================
`2.` If the command line provided to ``toxfr'' contains only the name of the binary kernel to be converted, the program writes output to a file with the same name as the input file and with an extension specific to the transfer kernels for that kernel type:
                % toxfr dif_preenc174_nav_v1.bsp
                Converting: dif_preenc174_nav_v1.bsp
                        To: dif_preenc174_nav_v1.xsp
`` Note that the output file has extension ``.xsp'' because the program recognized the ``.bsp'' extension, standard for binary SPKs, and replaced it with the ``.xsp'' extension, standard for transfer format SPKs. If the program cannot recognize the extension of the input file, it gives the output file the ``.xfr'' extension. `` If a file with the name that ``toxfr'' picked for the output file already exists the program will not overwrite it and will stop with an error message instead. `3.` For ``toxfr'' to create a transfer file with a name different from the automatically picked ``default'' name, the output file name must be specified explicitly on the command line after the name of the binary kernel to be converted:
                % toxfr dif_preenc174_nav_v1.bsp my.xsp
                Converting: dif_preenc174_nav_v1.bsp
                        To: my.xsp
`` Assigning the output file name explicitly is usually needed when the output file should be placed into a different directory, when a transfer file with the name that would be generated by ``toxfr'' by default already exists and should be preserved, or when the input binary file has a non-standard extension. Top # TOBIN Top ## Task Statement Practice running ``tobin'', a command line utility program for converting SPICE kernels in transfer format to binary format, to convert the transfer format SPK file generated as part of the previous task (``TOXFR'' task):
       my.xsp
Detailed information about the ``tobin'' interface is provided in the program's User's Guide (tobin.ug). Top ## Steps `1.` Run ``tobin'' to see usage (help) display. `2.` Run ``tobin'' to convert the transfer SPK file ``my.xsp'' to binary format without explicitly specifying the output binary SPK file name. `3.` Run ``tobin'' to convert the transfer SPK file ``my.xsp'' to binary format with explicitly specifying the output binary SPK file name. Top ## Explanations `1.` Typing ``tobin'' by itself displays a short usage message explaining the command line syntax:
                % tobin

                ============================================================

                Toolkit version: N0061

                SPICE(USAGEERROR)

                Usage: tobin file.x* [file.b*]

                A traceback follows.  The name of the highest level module i
                TOBIN

                ============================================================
`2.` If the command line provided to ``tobin'' contains only the name of the transfer kernel to be converted, the program writes output to a file with the same name as the input file and with an extension specific to the binary kernels for that kernel type:
                % tobin my.xsp
                Converting: my.xsp
                        To: my.bsp
`` Note that the output file has extension ``.bsp'' because the program recognized the ``.xsp'' extension, standard for transfer SPKs, and replaced it with the ``.bsp'' extension, standard for binary SPKs. If the program cannot recognize the extension of the input file, it gives the output file the ``.bin'' extension. `` If a file with the name that ``tobin'' picked for the output file already exists the program will not overwrite it and will stop with an error message instead. `3.` For ``tobin'' to create a binary file with a name different from the automatically picked ``default'' name, the output file name must be specified explicitly on the command line after the name of the transfer kernel to be converted:
                % tobin my.xsp di_spk.bsp
                Converting: my.xsp
                        To: di_spk.bsp
`` Assigning the output file name explicitly is usually needed when the output file should be placed into a different directory, when a binary kernel with the name that would be generated by ``tobin'' by default already exists and should be preserved, or when the input transfer file has a non-standard extension. Top # CHRONOS Top ## Task Statement Practice running ``chronos'', a command line utility program for converting between various time systems and time formats, to perform a number of time conversions using these supporting kernels:
       naif0008.tls
       dii_sclkscet_00008_science.tsc
Detailed information about the ``chronos'' interface is provided in the program's User's Guide (chronos.ug). Top ## Steps `1.` Run ``chronos'' to see usage (help) display. `2.` Run ``chronos'' to convert UTC time ``2005 JUL 05 04:00:00'' to Ephemeris Time (ET) in calendar format. `3.` Run ``chronos'' to convert UTC time ``2005 JUL 05 04:00:00'' to ET seconds past J2000. `4.` Run ``chronos'' to convert UTC time ``2005 JUL 05 04:00:00'' to Deep Impact Impactor spacecraft SCLK time. Top ## Explanations `1.` Typing ``chronos'' by itself displays a half-page of usage (help) information explaining the command line syntax and all available command line options:
                % chronos

                CHRONOS -- Universal Time Conversion Tool
                Version 2.1.0, August 18, 2006

                CHRONOS Usage
                ------------------------------------------------------------

                   To convert time from one supported system/type to another

                      % CHRONOS -SETUP <setup file name OR kernel file name(
                                -FROM <"from" time system>
                               [-FROMTYPE <"from" time type>]
                                -TO <"to" time system>
                               [-TOTYPE <"to" time type>]
                               [-FORMAT <output time format picture>]
                                -TIME <input time> | -BATCH
                               [-SC <sc ID>]
                               [-CENTER <cental body ID>]
                               [-LANDINGTIME <UTC time of the landing>]
                               [-SOL1INDEX <index of the first SOL>]
                               [-NOLABEL]
                               [-TRACE]

                   To display usage:               % CHRONOS [-HELP|-H]
                   To display help:                % CHRONOS -USAGE|-U
                   To display setup file template: % CHRONOS -TEMPLATE

                   The case of command line switches is insignificant. Switc
                   square braces [] are optional. See User's Guide for detai
`` or with the ``-u'' or ``-usage'' option (even when files names and/or other options are also present):
                % chronos -u
                ...
`2.` To convert a UTC time to ET in calendar format ``chronos'' must be provided with the following information on the command line: the name of an LSK file specified using the ``-setup'' option, the ``utc'' tag identifying the input time system as UTC specified using the ``-from'' option, the ``et'' tag identifying the output time system as ET specified using the ``-to'' option, and the UTC time to be converted specified using the ``-time'' option:
                % chronos -setup naif0008.tls -from utc -to et -time 2005
                JUL 05 04:00:00

                2005-07-05, 04:01:04.184                          (ET/SCET)
`` In this run both the input time and the output time are assumed to be for the same instant and point in space, thus letting the ``-fromtype'' and ``-totype'' options default to SCET is appropriate. None of the other optional arguments are needed for this conversion because some of them are not applicable (for example ``-sc'' or ``-landingtime'') while the others are OK with their built in, default values. `` If this conversion had to be done for a large number of input UTC times, the most efficient way to do it would be to list these times, one per line, in a text file, replace ``-time 2005 JUL 05 04:00:00'' on the command line with ``-batch'' and pipe the contents of the text file into ``chronos'' via standard input. Then ``chronos'' would process the command line and load kernels only once and would print to standard output the converted time for each of the input times, one per line:
                % cat time.txt
                2005 JUL 05 04:00:00
                2005 JUL 05 05:00:00
                2005 JUL 05 06:00:00

                % chronos -setup naif0008.tls -from utc -to et -batch < tim
                e.txt

                2005-07-05, 04:01:04.184                          (ET/SCET)
                2005-07-05, 05:01:04.184                          (ET/SCET)
                2005-07-05, 06:01:04.184                          (ET/SCET)
`` The ``-nolabel'' option can be added to the command line to eliminate the trailing label accompanying each of the output times (``(ET/SCET)'' in the example above). `3.` To convert a UTC time to ET seconds past J2000 ``chronos'' must be provided with the following information on the command line: the name of an LSK file specified using the ``-setup'' option, the ``utc'' tag identifying the input time system as UTC specified using the ``-from'' option, the ``et'' tag identifying the output time system as ET specified using the ``-to'' option, the ``seconds'' tag identifying the output time type as seconds past J2000 specified using the ``-totype'' option, and the UTC time to be converted specified using the ``-time'' option:
                % chronos -setup naif0008.tls -from utc -to et -totype seco
                nds -time 2005 JUL 05 04:00:00

                173808064.184                                  (ET/SECONDS)
`4.` To convert a UTC time to SCLK ``chronos'' must be provided with the following information on the command line: the names of an LSK file and an SCLK file specified using the ``-setup'' option, the spacecraft ID specified using the ``-sc'' option, the ``utc'' tag specified using the ``-from'' option, the ``sclk'' tag identifying the output time system as SCLK specified using the ``-to'' option, and the UTC time to be converted specified using the ``-time'' option:
                % chronos -setup naif0008.tls dii_sclkscet_00008_science.t
                sc -sc -70 -from utc -to sclk -time 2005 JUL 05 04:00:00

                1/0173808000.118                               (SCLK/SCLK)
`` Note that both an LSK file and an SCLK file must be provided using the ``setup'' option because data from both files are needed for this conversion. Top # STATES Top ## Task Statement Practice running ``states'', an interactive cookbook program that demonstrates how to use Toolkit routines to obtain state vectors, to compute a state using these SPK and LSK files:
       di_finalenc_nav_v3.bsp
       naif0008.tls
Although the ``states'' program is not intended to be used as executable -- the primary purpose of including it in the toolkit is to provide a simple source code example of using high level toolkit functions that compute state vectors -- as all other Toolkit applications it comes with a User's Guide (states.ug) describing its interface. Top ## Steps `1.` run ``states'' to compute the geometric state of the comet TEMPEL 1 relative to the Sun at 2005 JUL 05 04:00:00 in the ECLIPJ2000 reference frame. Top ## Explanations `1.` After starting ``states'', follow the prompts and enter the name of the LSK file, the name of the SPK file, the name of the observing body, the name of the target body, the number of states to be calculated, the time, the name of the reference frame, and the desired aberration correction:
                % states

                                Welcome to STATES

                This program demonstrates the use of NAIF S- and P-
                Kernel (SPK) files and subroutines by computing the
                state of a target body as seen from an observing
                body at a number of epochs within a given time
                interval.

                Enter the name of a leapseconds kernel file: naif0008.tls

                Enter the name of a binary SPK ephemeris file: di_finalenc_n
                av_v3.bsp

                Enter the name of the observing body: sun

                Enter the name of a target body: tempel 1

                Enter the number of states to be calculated: 1

                Enter the UTC time: 2005 JUL 05 04:00:00

                Enter the inertial reference frame (eg:J2000): ECLIPJ2000

                Type of correction                              Type of stat
                ------------------------------------------------------------
                'LT+S'    Light-time and stellar aberration    Apparent stat
                'LT'      Light-time only                      True state
                'NONE'    No correction                        Geometric sta

                Enter LT+S, LT, or NONE: NONE

                Working ... Please wait

                For time 1 of 1, the state of:
                Body            : tempel 1
                Relative to body: sun
                In Frame        : ECLIPJ2000
                At UTC time     : 2005 JUL 05 04:00:00

                                 Position (km)              Velocity (km/s)
                            -----------------------     --------------------
                          X: -0.8549549029932106E+08      0.2719316117375332
                          Y: -0.2084670053553146E+09     -0.1115748888018338
                          Z:  0.9044625066075269E+06     -0.5462400774687403
                  MAGNITUDE:  0.2253193050667428E+09      0.2989641107150566
`` Note that ``states'' prompts only two file -- LSK and SPK. If additional kernels are required to compute a state of interest the easiest way to provide these kernels to ``states'' is to prepare a meta-kernel listing LSK and these kernels and enter the name of this meta-kernel in response to the LSK prompt instead of the LSK name. Top # SPKDIFF Top ## Task Statement Practice running ``spkdiff'', a command line utility program for comparing trajectories stored in two SPK files, to compare these SPK kernels:
       dif_preenc174_nav_v1.bsp
       di_finalenc_nav_v3.bsp
Detailed information about the ``spkdiff'' interface is provided in the program's User's Guide (spkdiff.ug). Top ## Steps `1.` Run ``spkdiff'' to see usage (help) display. `2.` Run ``spkdiff'' to generate the ``Basic Report'' on differences of the Deep Impact Flyby (DIF) trajectories relative to the comet Tempel 1 provided by ``dif_preenc174_nav_v1.bsp'' and ``di_finalenc_nav_v3.bsp''. `3.` Run ``spkdiff'' to generate the ``View Frame Statistics Report'' on differences of the DIF trajectories relative to Tempel 1 provided by ``dif_preenc174_nav_v1.bsp'' and ``di_finalenc_nav_v3.bsp''. `4.` Run ``spkdiff'' to generate the ``Difference Dump Report'' on differences of the DIF trajectories relative to Tempel 1 provided by ``dif_preenc174_nav_v1.bsp'' and ``di_finalenc_nav_v3.bsp''. `5.` Run ``spkdiff'' to generate the ``View Frame Difference Dump Report'' on differences of the DIF trajectories relative to Tempel 1 provided by ``dif_preenc174_nav_v1.bsp'' and ``di_finalenc_nav_v3.bsp''. `6.` Run ``spkdiff'' to generate the ``View Frame Difference Dump Report'' with time tags in ISO DOY format (YYYY-DOYTHR:MN:SC.###) on differences of the DIF trajectories relative to Tempel 1 provided by ``dif_preenc174_nav_v1.bsp'' and ``di_finalenc_nav_v3.bsp''. `7.` Run ``spkdiff'' to generate the ``View Frame Difference Dump Report'' with time tags in ISO DOY format (YYYY-DOYTHR:MN:SC.###) on differences of the DIF trajectories relative to Tempel 1 provided by ``dif_preenc174_nav_v1.bsp'' and ``di_finalenc_nav_v3.bsp'' during the interval from ``2005-186T03:00'' to ``2005-186T05:00''. `8.` Run ``spkdiff'' to generate the ``View Frame Difference Dump Report'' with time tags in ISO DOY format (YYYY-DOYTHR:MN:SC.###) on differences of the DIF trajectories relative to Tempel 1 provided by ``dif_preenc174_nav_v1.bsp'' and ``di_finalenc_nav_v3.bsp'' during the interval from ``2005-186T03:00'' to ``2005-186T05:00'' with states sampled every ten minutes. Top ## Explanations `1.` Typing ``spkdiff'' by itself displays a half-page of usage (help) information explaining the command line syntax and all available command line options:
                % spkdiff

                spkdiff -- Version 1.0.0, July 20, 2006 -- Toolkit Version N

                   spkdiff computes differences between geometric states obt
                   two SPK files and either displays these differences or sh
                   about them (see the User's Guide for more details.) The p

                      % spkdiff [options] <first SPK file> <second SPK file>

                   Options are shown below. Order and case of keys are not s
                   Values must be space-separated from keys, i.e. '-n 10', n

                      -b1 <first body name or ID>
                      -c1 <first center name or ID>
                      -r1 <first reference frame name>
                      -b2 <second body name or ID>
                      -c2 <second center name or ID>
                      -r2 <second reference frame name>
                      -k  <other kernel file name(s)>
                      -b  <interval start time>
                      -e  <interval stop time>
                      -s  <time step in seconds>
                      -n  <number of states: 2 to 1000000 (default: 1000)>
                      -f  <output time format (default: TDB seconds past J20
                      -t  <report type: basic|stats|dump|dumpvf (default: ba
`2.` To generate the ``Basic Report'' on differences between two SPK files it is sufficient in most cases to provide ``spkdiff'' only with the names of the SPK files:
                % spkdiff dif_preenc174_nav_v1.bsp di_finalenc_nav_v3.bsp

                #
                # Comparison of 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'S
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # with 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'S
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # evenly-spaced with 171.14114108565 second (0d 0h 2m 51.141
                # within the time interval
                #
                #    from '2005 JUL 03 06:16:04.184 TDB' (173643364.18405 TD
                #    to   '2005 JUL 05 05:45:34.183 TDB' (173814334.18399 TD
                #

                Relative differences in state vectors:

                                              maximum                 averag

                  Position:             5.7433875616092E-07      2.658197967
                  Velocity:             3.5311760378989E-03      7.037404294

                Absolute differences in state vectors:

                                              maximum                 averag

                  Position (km):        1.2918999431552E+02      5.989230358
                  Velocity (km/s):      7.9483307482710E-02      1.581288819
`` Note that the order in which SPK names are provided on the command line affects the choice of the body-center-frame combination, for which the states used in comparison will be calculated because the program picks this combination by examining the first SPK file. In cases when the program picks a body-center-frame combination for which the second SPK file does not contain data, it will display an error message rather than doing a comparison. This would be the case if the ``di_finalenc_nav_v3.bsp'' SPK file was listed first of the two SPKs used in this step. ``spkdiff'' would attempt to make a comparison for the Deep Impact Impactor (DII) spacecraft (the segment for DII is the first segment in ``di_finalenc_nav_v3.bsp'', thus DII will be picked as the body) for which the other SPK does not contain data:
                % spkdiff di_finalenc_nav_v3.bsp dif_preenc174_nav_v1.bsp

                ============================================================

                Toolkit version: N0061

                SPICE(3NODATAFORBODY)

                SPK file 'dif_preenc174_nav_v1.bsp' does not contain data fo
                body 'DEEP IMPACT IMPACTOR SPACECRAFT'(-70) specified on the

                A traceback follows.  The name of the highest level module i
                spkdiff --> CHWCML

                ============================================================
`` In such cases -- and, in general, in any case when the SPKs that are being compared provide data for more than one body -- it is better to explicitly specify the name or the ID of the body for which comparison is sought using either the ``-b1'' option or the ``-b2'' option:
                % spkdiff -b1 -140 di_finalenc_nav_v3.bsp dif_preenc174_nav_
                v1.bsp

                #
                # Comparison of 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # with 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # evenly-spaced with 171.14114108565 second (0d 0h 2m 51.141
                # within the time interval
                #
                #    from '2005 JUL 03 06:16:04.184 TDB' (173643364.18405 TD
                #    to   '2005 JUL 05 05:45:34.183 TDB' (173814334.18399 TD
                #

                Relative differences in state vectors:

                                              maximum                 averag

                  Position:             2.2265666444092E-01      1.341183451
                  Velocity:             7.7342629071411E-03      1.550818952

                Absolute differences in state vectors:

                                              maximum                 averag

                  Position (km):        2.0310929065151E+02      1.568497359
                  Velocity (km/s):      7.9470466093664E-02      1.582125015
`` Note that the basic reports generated by the
                % spkdiff dif_preenc174_nav_v1.bsp di_finalenc_nav_v3.bsp

                ...
`` and the
                % spkdiff -b1 -140 di_finalenc_nav_v3.bsp dif_preenc174_nav_
                v1.bsp

                ...
`` commands are different. The first of the two reports is for DIF trajectories relative to the Sun (DIF-Sun is the body-center pair picked from ``dif_preenc174_nav_v1.bsp'') while the second is for DIF trajectories relative to the comet Tempel 1 (DIF-Tempel 1 is the body-center pair picked from ``di_finalenc_nav_v3.bsp''). Similar to that for bodies, ``spkdiff'' has options -- ``-c1'' and ``-c2'' -- that can be used to specify the centers for trajectories sampled from each of the two SPKs explicitly. `3.` To generate the ``View Frame Statistics Report'' on differences between two SPK files ``spkdiff'' must be provided with the ``stats'' tag using the ``-t'' option, followed by the options (if any are needed) picking the right body-center-frame combination for each of the two SPK files, followed by the names of the files:
                % spkdiff -t stats -b1 -140 -c1 1000093 di_finalenc_nav_v3.b
                sp dif_preenc174_nav_v1.bsp

                #
                # Comparison of 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # with 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # evenly-spaced with 171.14114108565 second (0d 0h 2m 51.141
                # within the time interval
                #
                #    from '2005 JUL 03 06:16:04.184 TDB' (173643364.18405 TD
                #    to   '2005 JUL 05 05:45:34.183 TDB' (173814334.18399 TD
                #

                1) Average components of position difference vectors in view
                   frame coordinates:

                   1a) Down track (km):                        141.304792673

                   1b) In orbit plane (km):                    2.19944880951

                   1c) Normal to orbit plane (km):            -2.54558248303

                   1d) Average delta time down track (sec):    13.8592441085

                ...

                   5e) Epoch (TDB, seconds past J2000):        173643364.184

                   5f) Epoch (TDB, calendar format):           2005-JUL-03-0
`` Note that to facilitate filtering and parsing of this report using utilities like ``grep'' each of the items in the report occupies a separate line that starts with a unique ``identifier'' (``1a)'', ``1b)'', etc.) and ends with the item value. `4.` To generate the ``Difference Dump Report'' on differences between two SPK files ``spkdiff'' must be provided with the ``dump'' tag using the ``-t'' option, followed by the options (if any are needed) picking the right body-center-frame combination for each of the two SPK files, followed by the names of the files:
                % spkdiff -t dump -b1 -140 -c1 1000093 di_finalenc_nav_v3.bs
                p dif_preenc174_nav_v1.bsp

                #
                # Comparison of 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # with 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # evenly-spaced with 171.14114108565 second (0d 0h 2m 51.141
                # within the time interval
                #
                #    from '2005 JUL 03 06:16:04.184 TDB' (173643364.18405 TD
                #    to   '2005 JUL 05 05:45:34.183 TDB' (173814334.18399 TD
                #
                # time, (x1-x2), (y1-y2), (z1-z2), (vx1-vx2), (vy1-vy2), (vz
                1.7364336418405E+08 -1.8375003233796E+02 -7.1250147502171E+0
                1.7364353532519E+08 -1.7444854285719E+02 -6.7077228545619E+0
                1.7364370646633E+08 -1.6884788472275E+02 -6.4548013248423E+0
                1.7364387760747E+08 -1.6697802157979E+02 -6.3678136817645E+0
                1.7364404874861E+08 -1.6689960146637E+02 -6.3603913064115E+0
                ...
                1.7381416304285E+08 -7.0171493083122E+01 -3.9950623055687E+0
                1.7381433418399E+08 -7.0069659960689E+01 -3.9935477027262E+0
`` Since both ``dump'' reports print all difference lines to the screen at once, users may find it desirable to pipe ``spkdiff''s output through ``more'' or a similar utility to be able to read the displayed text starting from the top. `5.` To generate the ``View Frame Difference Dump Report'' on differences between two SPK files ``spkdiff'' must be provided with the ``dumpvf'' tag using the ``-t'' option, followed by the options (if any are needed) picking the right body-center-frame combination for each of the two SPK files, followed by the names of the files:
                % spkdiff -t dumpvf -b1 -140 -c1 1000093 di_finalenc_nav_v3.
                bsp dif_preenc174_nav_v1.bsp

                #
                # Comparison of 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # with 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # evenly-spaced with 171.14114108565 second (0d 0h 2m 51.141
                # within the time interval
                #
                #    from '2005 JUL 03 06:16:04.184 TDB' (173643364.18405 TD
                #    to   '2005 JUL 05 05:45:34.183 TDB' (173814334.18399 TD
                #
                # time, down_track_p_diff, normal_to_plane_p_diff, in_plane_
                1.7364336418405E+08 +1.5782062666755E+02 -8.6614056142247E+0
                1.7364353532519E+08 +1.4649666193458E+02 -8.6381063884318E+0
                1.7364370646633E+08 +1.3972679080400E+02 -8.6148850160950E+0
                ...
                1.7381416304285E+08 +1.4144474095255E+02 +7.4490533513132E+0
                1.7381433418399E+08 +1.4144339442723E+02 +7.4664581930583E+0
`6.` To generate the ``View Frame Difference Dump Report'' on differences between two SPK files with times given in ISO DOY format ``spkdiff'' must be provided with the ``dumpvf'' tag using the ``-t'' option, the picture describing the ISO DOY time format (per TIMOUT requirement) using the ``-f'' option, a LSK file name using ``-k'' option, the options (if any are needed) picking the right body-center-frame combination for each of the two SPK files, followed by the names of the files:
                % spkdiff -t dumpvf -f 'YYYY-DOYTHR:MN:SC.###' -k naif0008.t
                ls -b1 -140 -c1 1000093 di_finalenc_nav_v3.bsp dif_preenc174
                _nav_v1.bsp

                #
                # Comparison of 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # with 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # evenly-spaced with 171.14114108565 second (0d 0h 2m 51.141
                # within the time interval
                #
                #    from '2005 JUL 03 06:16:04.184 TDB' (173643364.18405 TD
                #    to   '2005 JUL 05 05:45:34.183 TDB' (173814334.18399 TD
                #
                # using additional data from these kernels
                #
                #    'naif0008.tls'
                #
                # time, down_track_p_diff, normal_to_plane_p_diff, in_plane_
                2005-184T06:15:00.000 +1.5782062666755E+02 -8.6614056142247E
                2005-184T06:17:51.141 +1.4649666193458E+02 -8.6381063884318E
                2005-184T06:20:42.282 +1.3972679080400E+02 -8.6148850160950E
                ...
                2005-186T05:41:38.858 +1.4144474095255E+02 +7.4490533513132E
                2005-186T05:44:30.000 +1.4144339442723E+02 +7.4664581930583E
`` Providing an LSK file is required when the ``-f'' option is specified because the program uses SPICE's TIMOUT routine to format times for output and this routine needs LSK data. If no LSK is given on the command line when time formatting is requested ``spkdiff'' will stop with the following error:
                % spkdiff -t dumpvf -f 'YYYY-DOYTHR:MN:SC.###' -b1 -140 -c1
                1000093 di_finalenc_nav_v3.bsp dif_preenc174_nav_v1.bsp

                #
                ...
                ============================================================

                Toolkit version: N0061

                SPICE(MISSINGTIMEINFO)

                The following, needed to convert between the input uniform t
                not found in the kernel pool: DELTET/DELTA_T_A, DELTET/K, DE
                Your program may have failed to load a leapseconds kernel. O
                causes of this problem include loading an invalid leapsecond
                lacks an initial \begindata marker or final newline characte
                corrupted---or deleting previously loaded kernel pool variab
                UNLOAD, KCLEAR, or CLPOOL. Use the SPICE routine FURNSH (in
                FURNSH is an entry point of KEEPER) to load a leapseconds ke
                kernel is up to date. See the Kernel and Time Required Readi
                Kernels" and "LSK and SCLK" SPICE Tutorials for details.

                A traceback follows.  The name of the highest level module i
                spkdiff --> STDIFF --> TIMOUT --> UNITIM

                ============================================================
`7.` To generate a report on differences between two SPK files for a specified interval of time ``spkdiff'' must be provided with the begin and end times of this interval using the ``-b'' and ``-e'' options in addition to any other options followed by the names of the files:
                % spkdiff -t dumpvf -f 'YYYY-DOYTHR:MN:SC.###' -k naif0008.t
                ls -b 2005-186T03:00 -e 2005-186T05:00 -b1 -140 -c1 1000093
                di_finalenc_nav_v3.bsp dif_preenc174_nav_v1.bsp

                #
                # Comparison of 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # with 1000 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # evenly-spaced with 7.2072072048803 second (0d 0h 0m 7.2072
                # within the time interval
                #
                #    from '2005 JUL 05 03:01:04.183 TDB' (173804464.18399 TD
                #    to   '2005 JUL 05 05:01:04.183 TDB' (173811664.18399 TD
                #
                # using additional data from these kernels
                #
                #    'naif0008.tls'
                #
                # time, down_track_p_diff, normal_to_plane_p_diff, in_plane_
                2005-186T03:00:00.000 +1.4154921446446E+02 +6.4448848992533E
                2005-186T03:00:07.207 +1.4154907859830E+02 +6.4455384786604E
                2005-186T03:00:14.414 +1.4154892614482E+02 +6.4461575858493E
                ...
                2005-186T04:59:52.792 +1.4147346706276E+02 +7.1817591286974E
                2005-186T05:00:00.000 +1.4147347203042E+02 +7.1825243077425E
`8.` To generate a report on differences between two SPK files using states sampled at a specified time step ``spkdiff'' must be provided with the time step in seconds using the ``-s'' option in addition to any other options followed by the names of the files:
                % spkdiff -t dumpvf -f 'YYYY-DOYTHR:MN:SC.###' -k naif0008.t
                ls -b 2005-186T03:00 -e 2005-186T05:00 -s 600 -b 1 -140 -c1
                1000093 di_finalenc_nav_v3.bsp dif_preenc174_nav_v1.bsp

                #
                # Comparison of 13 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'di_finalenc_nav_v3.bsp'
                #
                # with 13 'J2000'-referenced geometric states
                #
                #    of 'DEEP IMPACT FLYBY SPACECRAFT' (-140) relative to 'T
                #    from SPK 'dif_preenc174_nav_v1.bsp'
                #
                # evenly-spaced with 600.00000000000 second (0d 0h 10m 0.000
                # within the time interval
                #
                #    from '2005 JUL 05 03:01:04.183 TDB' (173804464.18399 TD
                #    to   '2005 JUL 05 05:01:04.183 TDB' (173811664.18399 TD
                #
                # using additional data from these kernels
                #
                #    'naif0008.tls'
                #
                # time, down_track_p_diff, normal_to_plane_p_diff, in_plane_
                2005-186T03:00:00.000 +1.4154921446446E+02 +6.4448848992533E
                2005-186T03:10:00.000 +1.4154314730387E+02 +6.5040755037385E
                2005-186T03:20:00.000 +1.4153731846733E+02 +6.5643598474778E
                2005-186T03:30:00.000 +1.4153124096038E+02 +6.6256300011018E
                2005-186T03:40:00.000 +1.4152459254164E+02 +6.6862766878730E
                2005-186T03:50:00.000 +1.4151855690873E+02 +6.7469944286093E
                2005-186T04:00:00.000 +1.4151230121125E+02 +6.8089315976010E
                2005-186T04:10:00.000 +1.4150583588593E+02 +6.8699758002280E
                2005-186T04:20:00.000 +1.4149967515646E+02 +6.9332270052340E
                2005-186T04:30:00.000 +1.4149333543142E+02 +6.9947127932754E
                2005-186T04:40:00.000 +1.4148606471834E+02 +7.0575019380439E
                2005-186T04:50:00.000 +1.4148022258664E+02 +7.1203995033684E
                2005-186T05:00:00.000 +1.4147347203042E+02 +7.1825243077425E
Top # FRMDIFF Top ## Task Statement Practice running ``frmdiff'', a command line utility program for comparing or sampling frame orientations. In this exercise you will compare or sample orientations of CASSINI frames defined in and/or supported by these kernels:
       08110_08152pl_live.bc
       08132_08137ra.bc
       cas_v40.tf
       cas00137.tsc
       naif0008.tls
Detailed information about the ``frmdiff'' interface is provided in the program's User's Guide (frmdiff.ug). Top ## Steps `1.` Run ``frmdiff'' to see usage (help) display. `2.` Run ``frmdiff'' to generate the ``Basic Report'' on differences of the CASSINI spacecraft orientations relative to the J2000 inertial frame provided by ``08132_08137ra.bc'' and ``08110_08152pl_live.bc''. `3.` Run ``frmdiff'' to generate the ``Statistics Report'' on differences of the CASSINI spacecraft orientations relative to the J2000 inertial frame provided by ``08132_08137ra.bc'' and ``08110_08152pl_live.bc'' using a 5 second step size. `4.` Run ``frmdiff'' to generate the ``Angle and Axis Difference Dump Report'' on differences of the CASSINI spacecraft orientations relative to the J2000 inertial frame provided by ``08132_08137ra.bc'' and ``08110_08152pl_live.bc'' using a 10 second step size. `5.` Run ``frmdiff'' to generate the ``SPICE-Style Quaternion Dump Report'' sampling the CASSINI spacecraft orientation and angular velocity relative to the J2000 inertial frame provided by ``08132_08137ra.bc'', tagged with SCLK times with a 10 second step size. `6.` Run ``frmdiff'' to generate the ``Euler Angle Dump Report'' sampling the CASSINI spacecraft orientation relative to the J2000 inertial frame provided by ``08132_08137ra.bc''. The report should contain Euler angles in degrees for a ``Z-Y-Z'' rotation sequence tagged with UTC in ISO DOY format (YYYY-DOYTHR:MN:SC.###) with a 1 second step size during the interval from ``2008-MAY-12 10:00'' to ``2008-MAY-12 12:00'' UTC. `7.` Run ``frmdiff'' to generate the ``Coverage Intervals Dump Report'' for ``08132_08137ra.bc'' with time tags shown as UTC in ISO DATE format (YYYY-MM-DDTHR:MN:SC.###). `8.` Run ``frmdiff'' to generate the ``Coverage Gaps Dump Report'' for ``08132_08137ra.bc'' with time tags shown as UTC in ISO DATE format (YYYY-MM-DDTHR:MN:SC.###). `9.` Run ``frmdiff'' to display misalignment between the ``CASSINI_ISS_NAC'' and ``CASSINI_ISS_WAC'' frames as Euler angles in degrees for an ``X-Y-Z'' rotation sequence. Top ## Explanations `1.` Typing ``frmdiff'' by itself displays a half-page of usage (help) information explaining the command line syntax and all available command line options:
                % frmdiff

                frmdiff -- Version 1.0.0, February 10, 2009 -- Toolkit Versi

                   frmdiff provides a simple way of sampling orientation of
                   comparing orientations of two frames known to SPICE and s
                   data from SPICE kernels. The program usage is:

                      % frmdiff [options] <first kernel name> <second kernel
                      % frmdiff [options] <kernel name>
                      % frmdiff [options]

                   where kernel can be a CK, an FK, or a PCK. Options are sh
                   Order and case of keys are not significant. Values must b
                   space-separated from keys, i.e. '-n 10', not '-n10'.

                      -k  <supporting kernel(s) name(s)>
                      -f1 <first ``from'' frame, name or ID>
                      -t1 <first ``to'' frame, name or ID>
                      -c1 <first frame for coverage look up, name or ID>
                      -k1 <additional supporting kernel(s) for first file>
                      -f2 <second ``from'' frame, name or ID>
                      -t2 <second ``to'' frame, name or ID>
                      -c2 <second frame for coverage look up, name or ID>
                      -k2 <additional supporting kernel(s) for second file>
                      -a  <compare angular velocities: yes|no>
                      -m  <frame for angular velocities: from|to>
                      -b  <interval start time>
                      -e  <interval stop time>
                      -n  <number of points: 1 to 1000000 (default: 1000)>
                      -s  <time step in seconds>
                      -f  <time format: et|sclk|sclkd|ticks|picture_for_TIMO
                      -t  <report: basic|stats|dumpaa|dumpm|dumpqs|dumpqo|du
                      -o  <rotation axes order (default: z y x)>
                      -x  <units for output angles> (only for -t dumpaa and
`2.` To generate the ``Basic Report'' on differences between two CK files it is sufficient in most cases to provide ``frmdiff'' only with the names of the supporting LSK, SCLK, and FK files using the ``-k'' option and the names of the two CK files:
                % frmdiff -k naif0008.tls cas00137.tsc cas_v40.tf 08132_0813
                7ra.bc 08110_08152pl_live.bc

                #
                # Comparison of 994 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08132_08137ra.bc
                #
                # with 994 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08110_08152pl_live.bc
                #
                # with a 261.76763488717 second (0:00:04:21.767635) step siz
                # within the non-continuous (with 5 gaps) time period
                #
                #    from '2008 MAY 11 00:01:06.765' TDB (263736066.76544 TD
                #    to   '2008 MAY 14 00:01:05.184' TDB (263995265.18467 TD
                #

                Absolute difference magnitudes:

                                                     maximum

                  Rotation (rad):             +2.1382305885650E-02      +5.9
`` Note that the two CKs to be compared have to be provided as the last two items on the command line while all supporting kernels must be provided before them. Also note that in this case the program automatically picked the frames and the time interval for comparison by examining the data in the first of the two CKs (``08132_08137ra.bc'') and included these names and time boundaries as well as the other automatically picked items -- the time step and the number of steps -- in the report header. `3.` To generate the ``Statistics Report'' on differences between two CK files using a particular sampling step ``frmdiff'' must be provided with the names of supporting kernels specified using the ``-k'' option, the ``stats'' tag using the ``-t'' option, and the step size using the ``-s'' option, followed by the names of two CKs to be compared:
                % frmdiff -k naif0008.tls cas00137.tsc cas_v40.tf -t stats
                -s 5 08132_08137ra.bc 08110_08152pl_live.bc

                #
                # Comparison of 51731 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08132_08137ra.bc
                #
                # with 51731 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08110_08152pl_live.bc
                #
                # with a 5.0000000000000 second (0:00:00:05.000000) step siz
                # within the non-continuous (with 5 gaps) time period
                #
                #    from '2008 MAY 11 00:01:06.765' TDB (263736066.76544 TD
                #    to   '2008 MAY 14 00:01:05.184' TDB (263995265.18467 TD
                #

                1) Average difference

                   1a) Rotation (rad):                               0.00059

                2) RMS of difference

                   2a) Rotation (rad):                               0.00239

                3) Maximum rotation difference

                   3a) Rotation (rad):                               0.02205

                   3b) Epoch (TDB, seconds past J2000):              2638568

                   3c) Epoch (TDB, calendar format):                 2008-MA
`` To facilitate filtering and parsing of this report using utilities like ``grep'' each of the items in the report occupies a separate line that starts with a unique ``identifier'' (``1a)'', ``3a)'', etc.) and ends with the item value. `4.` To generate the ``Angle and Axis Difference Dump Report'' on differences between two CK files using a particular sampling step ``frmdiff'' must be provided with the names of supporting kernels specified using the ``-k'' option, the ``dumpaa'' tag using the ``-t'' option, and the step size using the ``-s'' option, followed by the names of two CKs to be compared:
                % frmdiff -k naif0008.tls cas00137.tsc cas_v40.tf -t dumpaa
                -s 10 08132_08137ra.bc 08110_08152pl_live.bc

                #
                # Comparison of 25869 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08132_08137ra.bc
                #
                # with 25869 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08110_08152pl_live.bc
                #
                # with a 10.000000000000 second (0:00:00:10.000000) step siz
                # within the non-continuous (with 5 gaps) time period
                #
                #    from '2008 MAY 11 00:01:06.765' TDB (263736066.76544 TD
                #    to   '2008 MAY 14 00:01:05.184' TDB (263995265.18467 TD
                #
                # Times are TDB seconds past J2000.
                #
                # angle is shown in radians.
                #
                # time, angle, axis_x, axis_y, axis_z
                +2.6373606676544E+08 +7.0339739249521E-04 -7.0414946683369E-
                +2.6373607676544E+08 +7.1952179054201E-04 -3.1512009275414E-
                +2.6373608676544E+08 +7.7560586484534E-04 -1.6887101147269E-
                ...
                +2.6399524722951E+08 +2.4560146109228E-05 +1.5574999384954E-
                +2.6399525722951E+08 +4.6330796897041E-05 -1.1215437867925E-
                +2.6399526518467E+08 +4.3066921035168E-05 +2.1392352889108E-
`` Since all ``dump'' reports print all difference or sample lines to the screen at once, users may find it desirable to pipe ``frmdiff''s output through ``more'' or a similar utility to be able to read the displayed text starting from the top, or to redirect the output to a file for subsequent plotting. `5.` To generate the ``SPICE-Style Quaternion Dump Report'' with samples of orientation and angular velocity from a CK file using a particular sampling step ``frmdiff'' must be provided with the names of supporting kernels specified using the ``-k'' option, the ``dumpqs'' tag using the ``-t'' option, the step size using the ``-s'' option, and the ``yes'' tag using the ``-a'' option, followed by the name of the CK from which orientation is to be sampled:
                % frmdiff -k naif0008.tls cas00137.tsc cas_v40.tf -t dumpqs
                -s 10 -a yes 08132_08137ra.bc

                #
                # Sampling of 25869 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08132_08137ra.bc
                #
                # with a 10.000000000000 second (0:00:00:10.000000) step siz
                # within the non-continuous (with 5 gaps) time period
                #
                #    from '2008 MAY 11 00:01:06.765' TDB (263736066.76544 TD
                #    to   '2008 MAY 14 00:01:05.184' TDB (263995265.18467 TD
                #
                # including angular velocities relative to 'from' frame.
                #
                # Times are TDB seconds past J2000.
                #
                # time, q_cos, q_sin1, q_sin2, q_sin3, av_x, av_y, av_z
                +2.6373606676544E+08 +4.2765566350171E-01 +6.1995251219409E-
                +2.6373607676544E+08 +4.1487117144731E-01 +6.2143765069334E-
                +2.6373608676544E+08 +4.0196021073660E-01 +6.2267117608015E-
                ...
                +2.6399524722951E+08 +4.6868056473485E-01 -1.2207597036621E-
                +2.6399525722951E+08 +4.6870380200417E-01 -1.2237579486654E-
                +2.6399526518467E+08 +4.6870380004563E-01 -1.2237920889302E-
`` Note that the report header indicates that the program was run in the sampling mode and that the output table includes angular velocities relative to the ``from'' frame in addition to quaternions. `6.` To generate the ``Euler Angle Dump Report'' with samples of orientation using a particular sampling step over a particular interval of time with angles in particular units for a particular rotation sequence and report time tags shown as UTCs in a particular format ``frmdiff'' must be provided with the names of supporting kernels specified using the ``-k'' option, the ``dumpea'' tag using the ``-t'' option, the step size using the ``-s'' option, the time boundaries using the ``-b'' and ``-e'' options, the angle rotation sequence using the ``-o'' option, the angle units using the ``-x'' option and the output time format using the ``-f'' option (for ISO DOY the format string is 'YYYY-DOYTHR:MN:SC.### ::RND'), followed by the name of the CK from which orientation is to be sampled:
                % frmdiff -k naif0008.tls cas00137.tsc cas_v40.tf -t dumpea
                -s 1 -b 2008-MAY-12 10:00 -e 2008-MAY-12 12:00 -o z y z
                -x degrees -f 'YYYY-DOYTHR:MN:SC.### ::RND' 08132_08137ra.bc

                #
                # Sampling of 7201 rotations
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08132_08137ra.bc
                #
                # with a 1.0000000000000 second (0:00:00:01.000000) step siz
                # within the continuous time period
                #
                #    from '2008 MAY 12 10:01:05.185' TDB (263858465.18530 TD
                #    to   '2008 MAY 12 12:01:05.185' TDB (263865665.18530 TD
                #
                # Times were generated by TIMOUT using 'YYYY-DOYTHR:MN:SC.##
                #
                # angles are shown in degrees.
                #
                # time, ang3_about_Z, ang2_about_Y, ang1_about_Z
                2008-133T10:00:00.000 +4.3056059795798E+01 +6.6322394077835E
                2008-133T10:00:01.000 +4.3073142191077E+01 +6.6235882496104E
                2008-133T10:00:02.000 +4.3094082386298E+01 +6.6150227150557E
                ...
                2008-133T11:59:58.000 +1.6306650969729E+02 +6.4432822285149E
                2008-133T11:59:59.000 +1.6299991511258E+02 +6.4483185277512E
                2008-133T12:00:00.000 +1.6293345369662E+02 +6.4533661172721E
`` This kind of report is very useful for sampling actual orientation provided in a CK file with respect to a dynamic frame representing an ideal orientation mode. For example, sampling actual CK-based orientation relative to a dynamic nadir-pointed frame with the +Z axis pointing nadir and the +X axis along the spacecraft velocity, with the output given as Euler angles for the Z-Y-X rotation sequence, would show angular offsets in yaw, pitch and roll angles. `7.` To generate the ``Coverage Intervals Dump Report'' with interval boundaries shown as UTCs in a particular format for a CK file ``frmdiff'' must be provided with the names of supporting kernels specified using the ``-k'' option, the ``dumpc'' tag using the ``-t'' option, and the output time format using the ``-f'' option (for ISO DATE the format string is ``YYYY-MM-DDTHR:MN:SC.### ::RND''), followed by the name of the CK for which the coverage report is to be shown:
                % frmdiff -k naif0008.tls cas00137.tsc cas_v40.tf -t dumpc
                -f 'YYYY-MM-DDTHR:MN:SC.### ::RND' 08132_08137ra.bc

                #
                # Coverage for rotation
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08132_08137ra.bc
                #
                # with a 261.76763488717 second (0:00:04:21.767635) step siz
                # within the non-continuous (with 5 gaps) time period
                #
                #    from '2008 MAY 11 00:01:06.765' TDB (263736066.76544 TD
                #    to   '2008 MAY 14 00:01:05.184' TDB (263995265.18467 TD
                #
                # Times were generated by TIMOUT using 'YYYY-MM-DDTHR:MN:SC.
                #
                # interval_start, interval_stop, interval_duration_sec, inte
                2008-05-11T00:00:01.580 2008-05-11T05:44:57.684       20696.
                2008-05-11T05:45:25.684 2008-05-11T22:29:53.258       60267.
                2008-05-11T22:30:13.258 2008-05-12T05:20:25.084       24611.
                2008-05-12T05:27:01.081 2008-05-12T13:37:52.873       29451.
                2008-05-12T13:39:40.873 2008-05-13T22:13:52.044      117251.
                2008-05-13T22:14:12.044 2008-05-13T23:59:59.999        6347.
`` Note that while this type of report is similar to the ``intervals'' report provided by ``ckrbrief,'' using the ``-dump'' option, ``frmdiff''s report is more flexible because it allows for a greater number of output time formats, more concise because it combines interval information that came from many segments into a single table, and more informative because it includes interval durations in addition to interval boundaries. `8.` To generate the ``Coverage Gaps Dump Report'' with gap boundaries shown as UTCs in a particular format for a CK file ``frmdiff'' must be provided with the names of supporting kernels specified using the ``-k'' option, the ``dumpg'' tag using the ``-t'' option, and the output time format using the ``-f'' option (for ISO DATE the format string is ``YYYY-MM-DDTHR:MN:SC.### ::RND''), followed by the name of the CK for which the gap report is to be shown:
                % frmdiff -k naif0008.tls cas00137.tsc cas_v40.tf -t dumpg
                -f 'YYYY-MM-DDTHR:MN:SC.### ::RND' 08132_08137ra.bc

                #
                # Coverage for rotation
                #
                #    from 'J2000' (1) to 'CASSINI_SC_COORD' (-82000)
                #    computed using
                #
                #       naif0008.tls cas00137.tsc cas_v40.tf
                #       08132_08137ra.bc
                #
                # with a 261.76763488717 second (0:00:04:21.767635) step siz
                # within the non-continuous (with 5 gaps) time period
                #
                #    from '2008 MAY 11 00:01:06.765' TDB (263736066.76544 TD
                #    to   '2008 MAY 14 00:01:05.184' TDB (263995265.18467 TD
                #
                # Times were generated by TIMOUT using 'YYYY-MM-DDTHR:MN:SC.
                #
                # gap_start, gap_stop, gap_duration_sec, gap_duration_string
                2008-05-11T05:44:57.684 2008-05-11T05:45:25.684          27.
                2008-05-11T22:29:53.258 2008-05-11T22:30:13.258          19.
                2008-05-12T05:20:25.084 2008-05-12T05:27:01.081         395.
                2008-05-12T13:37:52.873 2008-05-12T13:39:40.873         107.
                2008-05-13T22:13:52.044 2008-05-13T22:14:12.044          19.
`9.` To display the misalignment between two instrument frames defined as fixed-offset frames with respect to the spacecraft frame -- as is the case for the ``CASSINI_ISS_NAC'' and ``CASSINI_ISS_WAC'' frames -- ``frmdiff'' must be provided with the names of the FK (defining the frames) and LSK (needed to convert time bounds given on the command line) using the ``-k'' option, the names of the frames using the ``-f1'' and ``-t1'' options, the ``dumpea'' tag telling the program to display Euler angles using the ``-t'' option, the time boundaries set to the same arbitrary UTC using the ``-b'' and ``-e'' options, the angle rotation sequence using the ``-o'' option, and the angle units using the ``-x'' option:
                % frmdiff -k naif0008.tls cas_v40.tf -f1 CASSINI_ISS_NAC
                -t1 CASSINI_ISS_WAC -t dumpea -b 2005-01-01 -e 2005-01-01
                -o x y z -x degrees

                #
                # Sampling of 1 rotations
                #
                #    from 'CASSINI_ISS_NAC' (-82360) to 'CASSINI_ISS_WAC' (-
                #    computed using
                #
                #       naif0008.tls cas_v40.tf
                #
                # at continuous coverage intervals' endpoints
                # within the continuous time period
                #
                #    from '2005 JAN 01 00:01:04.183' TDB (157809664.18393 TD
                #    to   '2005 JAN 01 00:01:04.183' TDB (157809664.18393 TD
                #
                # Times are TDB seconds past J2000.
                #
                # angles are shown in degrees.
                #
                # time, ang3_about_X, ang2_about_Y, ang1_about_Z
                +1.5780966418393E+08 -3.6817224296505E-02 -2.4358034385368E-
`` Note that for a sampling or comparison run involving frames not supported by CKs or binary PCK the program has no way of automatically picking the frames and time boundaries and requires users to specify the frames and time boundaries explicitly on the command line.