KPL/SCLK \beginlabel PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM RECORD_BYTES = "N/A" ^SPICE_KERNEL = "mer1_hlst_tm20b3_v2.tsc" MISSION_NAME = "MARS EXPLORATION ROVER" SPACECRAFT_NAME = "MARS EXPLORATION ROVER 1" DATA_SET_ID = "MER1-M-SPICE-6-V1.0" KERNEL_TYPE_ID = SCLK PRODUCT_ID = "mer1_hlst_tm20b3_v2.tsc" PRODUCT_CREATION_TIME = 2004-07-22T16:54:36 PRODUCER_ID = "NAIF/JPL" MISSION_PHASE_NAME = "N/A" PRODUCT_VERSION_TYPE = ACTUAL PLATFORM_OR_MOUNTING_NAME = "N/A" START_TIME = "N/A" STOP_TIME = "N/A" SPACECRAFT_CLOCK_START_COUNT = "N/A" SPACECRAFT_CLOCK_STOP_COUNT = "N/A" TARGET_NAME = MARS INSTRUMENT_NAME = "N/A" NAIF_INSTRUMENT_ID = "N/A" SOURCE_PRODUCT_ID = "N/A" NOTE = "See comments in the file for details" OBJECT = SPICE_KERNEL INTERCHANGE_FORMAT = ASCII KERNEL_TYPE = CLOCK_COEFFICIENTS DESCRIPTION = "Special SCLK kernel implementing Hybrid Local Solar Time (HLST or LSTA/LSTB) system that was used during surface operations. " END_OBJECT = SPICE_KERNEL \endlabel MER-1 SCLK File Implementing Approximate Hybrid LST at TM20B3 (Meridiani) Site =========================================================================== This file is a SPICE spacecraft clock (SCLK) kernel that implements Approximate Hybrid Local Solar Time (HLST) accepted by the MER project. This file contains information required to convert between HLST at the MER-1 landing site TM20B3 (Meridiani) and Ephemeris Time (ET) using SPICE SCLK time conversion routines/tools. Version -------------------------------------------------------- 2.0.0 -- 2003-09-11/12:00 -- BVS/NAIF Updated the mean local second duration to match the value from the MER Planetary Constants document. The old value was 1.02749127; the new value is 1.02749125. 1.0.0 -- 2003-08-19/12:00 -- BVS/NAIF Initial Release References -------------------------------------------------------- 2. Ken Fujii, "MER LST - Continuous Time Option", 09/06/01 1. SCLK Required Reading Document Implementation Details -------------------------------------------------------- Per [1], the MER-1 HLST starts at "True" LST0 - 13 local minutes and runs at a constant rate of 1.02749125 ET seconds in 1 local Martian second. To implement correct counting of these fields in the SCLK subsystem, the HLST0 is computed as "True" LST0 for the midnight of SOL 1 shifted by 13 minutes, which at the TM20B3 (Meridiani) landing site corresponds to ET 128229003.0. The second-to-second rate given above translates to the SCLK rate of 88775.24400000 ET seconds in 1 local day, which appears in the COEFFICIENTS keyword below. The ID for this clock is chosen to be 253900 to indicate that this is NOT a actual SCLK for the MER-1 but rather a convenient way to implement HLST using SCLK subsystem of SPICE. HLST Format -------------------------------------------------------- The HLST string, the conversion for which is provided by this SCLK file, consists of four fields: DDD:HR:MN:SC where: DDD -- count of HLST (SOL) days HR -- count of HLST hours MN -- count of HLST minutes SC -- count of HLST seconds Usage -------------------------------------------------------- This file must be loaded into the user's program by a call to the FURNSH subroutine CALL FURNSH( 'this_file_name' ) furnsh_c ( "this_file_name" ); in order to use the SPICELIB SCLK family of subroutines to convert MER-1 HLST at the landing site TM20B3 (Meridiani) to ET and vice versa. Once loaded, the SCE2S/sce2s_c.f routines can be used to convert an ET time to an HLST string in the format DDD:HR:MN:SC: CALL SCE2S( -253900, ET, HLST ) sce2s_c ( -253900, et, maxlen, hlst ); and the routines SCS2E/scs2e_c can be used for backward conversion -- from HLST in DDD:HR:MN:SC format to ET: CALL SCS2E( -253900, HLST, ET ) scs2e_c ( -253900, hlst, &et ); Production/History of this SCLK file -------------------------------------------------------- This file was generated manually using the MER HLST definition provided in [1] and the HLST0 reference point computed for the landing site TM20B3 (Meridiani). Inquiries -------------------------------------------------------- If you have any questions regarding this file contact NAIF at JPL Charles H. Acton, Jr (818) 354-3869 Chuck.Acton@jpl.nasa.gov Boris V. Semenov (818) 354-8136 Boris.Semenov@jpl.nasa.gov Kernel DATA -------------------------------------------------------- \begindata SCLK_KERNEL_ID = ( @2003-09-11/12:00 ) SCLK_DATA_TYPE_253900 = ( 1 ) SCLK01_TIME_SYSTEM_253900 = ( 2 ) SCLK01_N_FIELDS_253900 = ( 4 ) SCLK01_MODULI_253900 = ( 24855 24 60 60 ) SCLK01_OFFSETS_253900 = ( 1 0 0 0 ) SCLK01_OUTPUT_DELIM_253900 = ( 2 ) SCLK_PARTITION_START_253900 = ( 0.0000000000000E+00 ) SCLK_PARTITION_END_253900 = ( 1.0995116277750E+12 ) SCLK01_COEFFICIENTS_253900 = ( 0.0000000000000E+00 128229003.0 88775.24400000 ) \begintext