PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = TEXT PUBLICATION_DATE = 1996-02-28 NOTE = "Software Interface Specification for the Orbit Propagation and Timing Geometry (OPTG) File" END_OBJECT = TEXT END Table of Contents * 1. General Description o 1.1 Purpose of Interface o 1.2 Scope o 1.3 Applicable Documents o 1.4 Functional Description + 1.4.1 Data Source, Destination, and Transfer Method + 1.4.2 Pertinent Relationships with Other Interfaces + 1.4.3 Labeling and Identification + 1.4.4 Assumptions and Constraints * 2. Environment o 2.1 Hardware Characteristics and Limitations o 2.2 Interface Medium and Characteristics o 2.3 Input/Output Protocols + 2.3.1 Device Addressing + 2.3.2 Operating System Protocols + 2.3.3 Deformatting + 2.3.4 Calling Sequence o 2.4 Failure Protection, Detection, and Recovery Features + 2.4.1 Backup Requirements + 2.4.2 Security/Integrity Measures o 2.5 End-of-File (or Medium) Conventions o 2.6 Utility Programs * 3. Data Flow Characteristics o 3.1 Operational Characteristics + 3.1.1 Generation Method and Frequency + 3.1.2 Time Span of Product o 3.2 Data Volume o 3.3 Flow Rate * 4. Detailed Data Object Definition o 4.1 Structure and Organization Overview o 4.2 Data Format and Definition + 4.2.1 SFDU Data Description + 4.2.2 Non-SFDU Data Description + 4.2.2.1 Header Records + 4.2.2.2 Data Records + 4.2.2.3 Last File Record * Appendix A. Acronyms 1. GENERAL DESCRIPTION 1.1 PURPOSE OF INTERFACE This Software Interface Specification (SIS) describes the content of the Orbit Propagation and Timing Geometry File (OPTG). It is intended that this interface will satisfy requirements for the Mars Global Surveyor (MGS) and Cassini missions. 1.2 SCOPE The format and syntax specifications in this SIS applies to all phases of the mission. 1.3 APPLICABLE DOCUMENTS 699-FSO/NAV-FRD-501 Cassini Functional Requirements and Design Document SFOC0038-01-09-01 10 Jan 94 SFOC-1-CDB-ANY-CATALOG2 SFOC0099-04-00 20 Nov 92 Data Dictionary, Rev C SFOC0038-00-08-01 26 Feb 88 SFOC-1-CDB-MGN-TIMESFILE SFOC0038-01-09-03 30 Aug 94 SFOC-2-SYS-ANY-TIMEFORMS 1 Oct 94 DPTRAJ-ODP User Reference Manual, SOM Vol. 1 and Vol. 2 1 Oct 94 DPTRAJ and ODP Interfaces and File Format Descriptions, SOM, Vol. 3 1.4 FUNCTIONAL DESCRIPTION The OPTG file contains data for many trajectory and/or geometry events relative to the spacecraft, e.g., periapsis and apoapsis passage times for an orbiter, Earth and Sun occultation times, inferior and superior conjunction times, and many other events. 1.4.1 Data Source, Destinations, and Transfer Method OPTG data shall be created by the DPTRAJ program TWIST running on the NAV computer system. The destination of this file is the Central Data Base (CDB). The transfer medium is via the MGSO network. 1.4.2 Pertinent Relationships with Other Interfaces The generation of this file is dependent upon the spacecraft ephemeris file availability spanning the time over which the OPTG file is desired. 1.4.3 Labeling and Identification Internal labeling of the OPTG file is accomplished with header records as defined in Section 4.2. 1.4.4 Assumptions and Constraints None. 2. ENVIRONMENT 2.1 HARDWARE CHARACTERISTICS AND LIMITATIONS Execution of the software to generate the OPTG file shall be on the NAV computer. 2.2 INTERFACE MEDIUM AND CHARACTERISTICS NAV computer catalogued file shall use the MGSO project LAN as the medium for transmittal to the CDB. 2.3 INPUT/OUTPUT PROTOCOLS None. 2.3.1 Device Addressing N/A 2.3.2 Operating System Protocols N/A 2.3.3 Deformatting Users of the OPTG file will be required to have software to remove the SFDU data from the CDB stored file. 2.3.4 Calling Sequence N/A 2.4 FAILURE PROTECTION, DETECTION, RECOVERY FEATURES 2.4.1 Backup Requirements The Navigation Subsystem shall keep the Orbit Propagation and Timing Geometry File in the NAV computer until it is confirmed as stored within the CDB. Backups will be maintained through normal archiving procedures of the CDB. Should the CDB malfunction or the network fail, customers of the OPTG File may obtain the file via the secondary method which is to receive the data in TBD form from the NAV Subsystem. 2.4.2 Security/Integrity Measures The CDB security/integrity measures will be in effect. 2.5 END-OF-FILE (OR MEDIUM) CONVENTIONS The end-of-file is marked with an $$EOF record. 2.6 UTILITY PROGRAMS Utility programs developed by MGSO shall be used to insert and remove SFDU labels from the OPTG file. 3. DATA FLOW CHARACTERISTICS 3.1 OPERATIONAL CHARACTERISTICS 3.1.1 Generation Method and Frequency The OPTG data shall be created by NAV DPTRAJ program TWIST. The file shall be generated at a frequency consistent with project requirements. 3.1.2 Time Span of Product The time span of the file is controlled by the span of the spacecraft ephemeris input to TWIST and by user input. 3.2 DATA VOLUME The size of the file depends on the length of the trajectory and the number of event triggers (TWIST input) encountered per orbit. 3.3 FLOW RATE Determined by the LAN traffic. 4. DETAILED DATA OBJECT DEFINITION 4.1 STRUCTURE AND ORGANIZATION OVERVIEW The OPTG file is an ASCII file which consists of the SFDU header, the OPTG headers, and the OPTG data. Each will be described in the following sections. 4.2 DATA FORMAT AND DEFINITION 4.2.1 SFDU Data Description The SFDU information and structure, for the OPTG file, is illustrated in the following example: CCSD3ZS00001AAAAAAAA NJPL3KS0L015BBBBBBBB MISSION_NAME=***; SPACECRAFT_NAME=***; DATA_SET_ID=OPTG; FILE_NAME=optg.sff; PRODUCER_ID=NAV; APPLICABLE_START_TIME=1994-04-04T07:00:00.000; APPLICABLE_STOP_TIME=1994-04-04T15:00:00.000; PRODUCT_CREATION_TIME=1990-08-01T15:35:09; CCSD3RE00000BBBBBBBB NJPL3IS0nnnnCCCCCCCC In the above *** will be MARS-GLOBAL-SURVEYOR or CASSINI depending on whether the mission is MGS or CASSINI. nnnn, the DDID, will be 0357 for MGS and 0380 for CASSINI. In the actual OPTG File, the following SFDU data is located at the end of the file, following the non-SFDU data which is described in Section 4.2.2. CCSD3RE00000CCCCCCCC CCSD3RE00000AAAAAAAA 4.2.2 Non-SFDU Data Description The non-SFDU portion of the OPTG file contains data described in Sections 4.2.2.1 and 4.2.2.2 as follows: 4.2.2.1 Header Records Header RECORD 1 - Identifies file type and version/delimits start of header. Column Content Description --------------------------------------------------------------------- 01-02 "$$" Control characters signifying major control card. 03-06 "XXXX" Key Word - identifies the mission for this file, e.g. CAS for Cassini, or MGS for Mars Global Surveyor. Left justified. 14-55 "ORBIT PROPAGATION Identifies the file AND TIMING GEOMETRY FILE" 57-60 "vnnn" Identifies the file version, eg v001. Header RECORD 2 - Identifies file name. Column Content Description ------------------------------------------------------------------ 01-01 "*" Header character 03-06 "OPTG" Key Word - identifies record type. 14-72 File name File name retrieved from the Fortran 77 execution of the INQUIRE statement. Could be, for example, OPTG_TEST.TXT Header RECORD 3 - Specifies the title of the OPTG file. Column Content Description -------------------------------------------------------------------- 01-01 "*" Header character 03-07 "TITLE" Key Word - identifies record type. 14-72 Title Any alphanumeric expression up to 59 characters, input by the user via the GIN file to NAV program TWIST that generates OPTG file. This could be used to identify the purpose of the OPTG file being generated. For example, this could be text that says, "This is a test OPTG file for the cruise phase." Header RECORD 4 - Specifies JPL local file creation time. Column Content Description ---------------------------------------------------------------------- 01-01 "*" Header character 03-10 "CREATION" Key Word - identifies date and time when OPTG file was created. 14-16 "JPL" Defines time base. 18-35 "YY-MMM-DD/hh:mm:ss" Date and time in local time format. For example, 88-DEC-18/14:32:45. Header RECORD 5 - Specifies SCE start time of file coverage. Column Content Description --------------------------------------------------------------------- 01-01 "*" Header character 03-07 "BEGIN" Key Word - identifies record type. 14-16 "SCE" Defines time base. 18-39 "YY-MMM-DD/hh:mm:ss.fff" S/C event time (ephemeris time) when the OPTG file is to begin. For example, 88-DEC-18/14:32:45.050. Header RECORD 6 - Specifies SCE cutoff time of file coverage. Column Content Description -------------------------------------------------------------------- 01-01 "*" Header character 03-08 "CUTOFF" Key Word - identifies record type. 14-16 "SCE" Defines time base. 18-39 "YY-MMM-DD/hh:mm:ss.fff" S/C event time (ephemeris time) when the OPTG file is to end. Header RECORD 7 - Specifies trajectory data base for run. Column Content Description ---------------------------------------------------------------------- 01-01 "*" Header character 03-07 "PFILE" Key Word - identifies record type. 14-16 "JPL" Defines time base. 18-35 "YY-MMM-DD/hh:mm:ss" The creation date and time of the PFILE used to make the OPTG file. For example, 88-DEC-18/14:32:45. Header RECORD 8 - Specifies program that created PFILE. Column Content Description ------------------------------------------------------------------ 01-01 "*" Header character 03-09 "PVDRIVE" Name of the program that generated or "PDRIVE" the PFILE used by TWIST to create or "SEPV" the OPTG file. 14-16 "JPL" Defines time base. 18-35 "YY-MMM-DD/hh:mm:ss" Creation date and time of the program that wrote the PFILE. Header RECORD 9 - Specifies run which produced OPTG file. Column Content Description --------------------------------------------------------------------- 01-01 "*" Header character