PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = TEXT PUBLICATION_DATE = 2002-04-09 NOTE = "Section 4 of Software Interface Specification for the Odyssey Small Forces Data File. This file describes structure and content of the ODY SFDF. The full document is Odyssey SIS-NAV016-M01, dated 20 March 2001." END_OBJECT = TEXT END 4.0 DETAILED INTERFACE SPECIFICATIONS 4.1 STRUCTURE AND ORGANIZATION OVERVIEW The Small Forces Data File is an ASCII file which consists of the decommutated SFDU header information and the Small Forces Data File (SFDF) data as deciphered by the SPAS Packet_Decom program. Each will be described in the following sections. 4.2 SUBSTRUCTURE DEFINITION AND FORMAT 4.2.1 Decommutated SFDU Header Information The decommutated SFDU header information for the Small Forces Data File is as follows: SFDU NUMBER: 1 ******************** ERT: 00/285-13:21:02.234 APID: 38 SEG_FLAGS: 3 (This is a Non-Segmented Packet) SRC_SEQ_CNT: 0 PACKET_LEN: 76 PACKET_SEC: 692209545 PACKET_SUB_SEC: 229 where SFDU_NUMBER represents the specific decimal number of the SFDU within the non-channelized packet file. ERT represents the UTC formatted Earth-Received Time recorded in the secondary CHDO of the SFDU APID represents the decimal equivalent of the non-channelized APID being decommutated - recorded in the packet primary header (see the MSP01 Orbiter Telemetry Dictionary, MSP01-98-0060 Volume 2) SEG_FLAGS represents the grouping flags as they correlate with segmenting packets - recorded in the packet primary header (see the MSP01 Orbiter Telemetry Dictionary, MSP01-98-0060 Volume 2) SRC_SEQ_CNT represents the decimal equivalent of the Source Sequence Count; packets are numbered sequentially for accountability - recorded in the packet primary header (see the MSP01 Orbiter Telemetry Dictionary, MSP01-98-0060 Volume 2) PACKET_LEN represents the decimal equivalent of the length of the packet in bytes not including the 5 bytes of the primary packet header - expressed as the number of bytes minus one (zero-biased) PACKET_SEC represents the decimal equivalent of the 32 bits of seconds (referenced to 1980-000T00:00:00) recorded in the packet secondary header (see the MSP01 Orbiter Telemetry Dictionary, MSP01-98-0060 Volume 2) PACKET_SUB_SEC represents the decimal equivalent of the 8 bits of sub-seconds recorded in the packet secondary header (see the MSP01 Orbiter Telemetry Dictionary, MSP01-98-0060 Volume 2) 4.2.2 Data Record The following items are passed to the user via ASCII text file (SFDF): ITEM FORMAT UNITS DESCRIPTION ----------------------------------------------------------------------------- SMALL_FORCES_START_TIME 32-bit int seconds # of seconds since 1980 - start time of collection of small forces data CUMULATIVE_DELTA-V_X_COMP* 32-bit flt meters/s resultant delta-v in the (13.11f) x-direction for the time period in m/sec CUMULATIVE_DELTA-V_Y_COMP* 32-bit flt meters/s resultant delta-v in the (13.11f) y-direction for the time period in m/sec CUMULATIVE_DELTA-V_Z_COMP* 32-bit flt meters/s resultant delta-v in the (13.11f) z-direction for the time period in m/sec AVG_ATT_QUAT_Q1** 32-bit flt numerical resultant attitude quarter- (13.11f) nion for the accumulation period - quat. 1 AVG_ATT_QUAT_Q2** 32-bit flt numerical resultant attitude quarter- (13.11f) nion for the accumulation period - quat. 2 AVG_ATT_QUAT_Q3** 32-bit flt numerical resultant attitude quarter- (13.11f) nion for the accumulation period - quat. 3 AVG_ATT_QUAT_Q4** 32-bit flt numerical resultant attitude quarter- (13.11f) nion for the accumulation period - quat. 4 RCS1_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for RCS1 RCS2_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for RCS2 RCS3_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for RCS3 RCS4_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for RCS4 TCM1_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for TCM1 TCM2_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for TCM2 TCM3_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for TCM3 TCM4_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for TCM4 ME1_ACC_ON_CMDS 16-bit int numerical number of firings during the accum period for main engine ME2_ACC_ON_CMDS 16-bit int numerical Not used; zero filled RCS1_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for RCS1 in millisecs RCS2_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for RCS2 in millisecs RCS3_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for RCS3 in millisecs RCS4_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for RCS4 in millisecs TCM1_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for TCM1 in millisecs TCM2_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for TCM2 in millisecs TCM3_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for TCM3 in millisecs TCM4_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for TCM4 in millisecs ME1_ACC_ON_TIME*** 16-bit int millisecs Accumulated ON time during the accum period for main engine in millisecs ME2_ACC_ON_TIME 16-bit int millisecs Not used; zero filled SMALL_FORCES_FILE string text Binary data file containing all of the above info (ONLY PRESENT WITH "-f" OPTION) SMALL_FORCES_SCLK float seconds Production time of the (15.5f) the packet from secondary header (32-bit int secs followed by rep of subseconds/256) * For the 3 Cumulative Delta-V Components, the coordinate system is Mars centered inertial (Mars Mean Equator and IAU-vector of Epoch J2000). ** For the Quaternion items, they are Mars centered inertial to body rotation. *** The on-times are represented as 16-bit unsigned integers, and will roll over at 65535 ms, or 65.535 sec.