PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2013-02-27 NOTE = "MSL C-Kernel Information" END_OBJECT = TEXT END General Information About SPICE C-Kernels ========================================= In the SPICE system, pointing data for an instrument platform, or for a specific instrument, are stored C-kernels. The pointing of a platform or an instrument is often expressed in terms of a transformation matrix from some standard inertial reference frame to a instrument-fixed frame. In the past, the instrument was often a camera, and the transformation was thus dubbed the ``C-matrix''; hence the choice of C as the name for the pointing kernel. The data contained in C-kernel files can be accessed and manipulated using the SPICE Toolkit APIs, calls to which can be integrated into user application programs. The information regarding how to obtain the SPICE system toolkit for a number of languages and computer platforms is located in the ``/software'' subdirectory of the main directory of this data set. To use C-kernels, a Spacecraft Clock Kernel (SCLK) is required. Also, for C-Kernels containing orientation of a project-defined frames, a Frame Definitions File is required. Refer to the ``ck.req'' document provided with the toolkit or available from the NAIF Node of PDS if SPICE toolkit is not included with this data set to get more information on how to access C-kernel data. MSL C-kernels Provided in This Data Set ======================================= The following MSL C-kernels are provided in this data set (only name portion of the file name is shown; the extension of all file names is ``.bc''): MSL Cruise Orientation CK Files: msl_cruise_recon_nospin CK file containing complete cruise orientation based on H-vector direction without modeling spin, provided by the MSL ACS Team. msl_cruise_recon_rawrt_vV CK files containing fully reconstructed orientation based on real-time quaternions covering only communication periods, provided by the MSL ACS Team. msl_cruise_recon_raweng_vV CK files containing fully reconstructed orientation based on high-rate quaternions covering only short periods around thruster firing events and ACS calibration activities, provided by the MSL ACS Team. msl_cruise_recon_nav_vV CK file containing fully reconstructed orientation based on H-vector direction and NAV de-spinned tracking data, covering only communication periods, provided by the MSL NAV Team. MSL EDL Orientation CK Files: msl_edl_vV CK files containing the reconstructed EDL orientation determined by the MSL EDL Team, JPL. The file with the latest version number V supersedes all previous versions. MSL Rover Orientation CK Files: msl_surf_rover_tlm_BBBB_EEEE_vV CK files containing the orientation of the rover relative to the local level frame, created using telemetry view data from OPGS PLACES server, covering SOLs "BBBB" to "EEEE", version V. MSL Articulating Structures Orientation CK Files: msl_surf_hga_tlm_BBBB_EEEE_vV CK files containing the orientation of the High Gain Antenna (HGA) relative to the rover frame, created using telemetry view data from OPGS PLACES server, covering SOLs "BBBB" to "EEEE", version V. msl_surf_ra_tlmenc_BBBB_EEEE_vV CK files containing the orientation of the Robotic Arm (RA) relative to the rover frame, created using encoder angles from telemetry view data from OPGS PLACES server, covering SOLs "BBBB" to "EEEE", version V. msl_surf_ra_tlmres_BBBB_EEEE_vV CK files containing the orientation of the Robotic Arm (RA) relative to the rover frame, created using resolver angles from telemetry view data from OPGS PLACES server, covering SOLs "BBBB" to "EEEE", version V. These CKs are more accurate compared to the encoder based RA CK but generally provide less coverage. msl_surf_rsm_tlmenc_BBBB_EEEE_vV CK files containing the orientation of the Remote Sensing Mast (RSM) relative to the rover frame, created using encoder angles telemetry view data from OPGS PLACES server, covering SOLs "BBBB" to "EEEE", version V. msl_surf_rsm_tlmres_BBBB_EEEE_vV CK files containing the orientation of the Remote Sensing Mast (RSM) relative to the rover frame, created using resolver angles from telemetry view data from OPGS PLACES server, covering SOLs "BBBB" to "EEEE", version V. These CKs are more accurate compared to the encoder based RSM CKs but generally provide less coverage. MSL RA Tool REF-to-Instrument Offsets CK Files: msl_ra_toolsref_vV CK files containing fixed orientations of the RA instrument frames relative to their corresponding REF frames. This is an auxiliary CK needed to complete the frame chain from the rover to the instruments mounted on RA. For all CK files whose names include version (V) the files with the latest version number supersede all files of the same kind with earlier versions. For all CK files whose names include SOL coverage boundaries (BBBB and EEEE) and version (V) the files with the later coverage range and the latest version number supersede competing data from files with earlier coverage and versions. Kernel File Details =================== The most detailed description of the data in a binary CK file is provided in metadata included inside the comment area of the file. This information can be viewed using utility programs COMMNT and SPACIT included into the NAIF Toolkit. Gaps in CK Coverage =================== Both cruise CKs and surface rover and articulating structures CKs have gaps in coverage. While in the cruise CKs cannot be ``closed'', surface CKs can be modified using the CKSPANIT utility program to provide continuous coverage obtained by linear interpolation over gaps, resulting in orientation during gaps that is less accurate but still possibly acceptable for some applications (e.g. visualization). To modify a rover or an articulating structure orientation CK to ``close'' coverage gaps, CKSPANIT can be run as follows: % ckspanit -in [input_ck] -out [output_ck] -tol 2E+12 -frm [fk] Contact Information =================== Regarding MSL project specific information provided in this data set and for general information about SPICE system: Boris Semenov (818)-354-8136 Boris.Semenov@jpl.nasa.gov address: Navigation and Ancillary Information Facility (NAIF) Jet Propulsion Laboratory MS 301-125L 4800 Oak Grove Drive Pasadena CA 91109 USA