Document title: Format description for NDADS DE RIMS Mission Analysis Files Project: DE NDADS Datatype: RIMS Super-EID: DOCUMENT There may be other documents also identified by this super-EID. NDADS filename: DOCUMENT_RIMS_MAFORMAT.SFD TRF entry: b46608.txt in NSSDC's controlled digital document library, Feb. 1998. Document text follows: ---------------------- TYPE_OF_FILE_NAME: Mission Analysis File FILE_ATTRIBUTES: Fixed length, sequential file LOGICAL_RECORD_LENGTH: 5624 bytes TYPE_OF_FILE_DESCRIPTION: Each MAF file data record consists of 8 seconds of RIMS data (512 samples, each sample is a 1/64 sec measurement), in time order. One record is 5624 bytes in size. The first 100 locations (16 bit words) of this record contains timing, orbit/attitude, B-field, and instrument mode information. Since the instrument mode takes some logic to decode, subroutines are provided that perform the decoding of the instrument flags, determination of RPA/IMS settings for any sample through the 512, and decommutation of the D and E channels (Z-head data). File names are of the form Dydddhhmm-hhmm.MF1_Y, where, D is at the beginning of all RIMS MAF files, y is the last digit of the year, ddd is the daycount of the year, hhmm is the start and then the stop hour and minute of the pass, and _Y indicates a compressed data file. FILE_STRUCTURE: MAF files are written as VAX unformatted sequential files with logical records of equal length. Note that each word is of type VI2 (VAX integer*2) FORMAT_OF_THE_LOGICAL_DATA_RECORD: WORD NUMBER CONTENTS COMMENTS 1-2 Mission ID 3 Date 4-5 Time 6 Time duration 7 Predict/Definitive Flag 8 Orbit number 9-11 GEI position (0.001 Re) 12-14 GEI velocity (0.01 km/s) 15 L Value (0.01) 16 Invariant latitude (0.01 deg) 17 Geomagnetic latitude (0.01 deg) 18 Geomagnetic longitude (0.01 deg) 19 Geomagnetic local time (0.01 hrs) 20 Spin rate (0.01 deg/s) 21-22 Sun angles (0.1 deg) 23 RAM angle (0.1 deg) 24 Eclipse Flag 25 B-field scale 26 Mag validity flag 27-36 Spare words 37-68 RPA memory 69-100 IMS memory 101-124 BX,BY,BZ 125-252 Channel A Housekeeping and status 253-764 Channel B Radial IMS low mass counts 765-1276 Channel C Radial IMS high mass counts 1277-1788 Channel F RPA accumulation 1789-2300 Channel D +Z IMS counts 2301-2812 Channel E - Z IMS counts DESCRIPTION: MAF contents MISSION_ID: Indicates Dynamics Explorer data DATE: The year and daynumber is coded as (YEAR-1980)*1000+DAYNUMBER TIME: The time of day is stored in location 4 and 5 as follows: WORD(4)=IMS/8000 WORD(5)=IMS-WORD(4)*8000 Where IMS is the 32-bit milliseconds of day field. Thus WORD(4) represents the number of 8 second intervals through the day (0-10799), while WORD(5) is the remaining millisecs(0-7999). The time in millisecs can be reconstituted in a two-step process by: IMS=WORD(4) IMS=IMS*8000+WORD(5) TIME_DURATION: Time duration in seconds of this record. PREDICT_DEFINITIVE_FLAG: Indicated quality of orbit/attitude information.0=definitive data, 1=predictive data, 2=data recreated at MSFC. ORBIT_NUMBER: The spacecraft orbit number. GEI_POSITION: Divide integer*2 word by 1000.0 (0.001 Re) GEI_VELOCITY: Divide integer*2 word by 100.0 (0.01 km/s) L_VALUE: The McIlwain L-value of the spacecraft. Divide integer*2 word by 100.0 (0.01) INVARIANT_LATITUDE: The invariant latitude of the spacecraft in degrees. Divide integer*2 word by 100.0 (0.01 deg) GEOMAGNETIC_LATITUDE: The geomagnetic latitude of the spacecraft in degrees. Divide integer*2 word by 100.0 (0.01 deg) GEOMAGNETIC_LONGITUDE: The geomagnetic longitude of the spacecraft in degrees. Divide integer*2 word by 100.0 (0.01 deg) GEOMAGNETIC_LOCAL_TIME: The geomagnetic local time of the spacecraft in hours. Divide integer*2 word by 100.0 (0.01 hrs) SPIN_RATE: Divide integer*2 word by 100.0 (0.01 deg/s) SUN_ANGLES: Angle between the spacecraft ram and the sun direction and the Z axis and the sun directions (2 seperate angles). Divide integer*2 word by 10.0 (0.1 deg) RAM_ANGLE: Angle measured from velocity vector to -X axis. Divide integer*2 word by 10.0 (0.1 deg) ECLIPSE_FLAG: 0: Spacecraft in sunlight; 1: Spacecraft in darkness. BFIELD_SCALE: MAG_VALIDITY_FLAG: Flag indicating validity of magnetic coordinates. 1: Good data SPARE_WORDS: For later use. RPA_MEMORY: The 32 Retarding Potential Analyzer (RPA) settings. IMS_MEMORY: The 32 Ion Mass Spectrometer (IMS) settings. BX_BY_BZ: Magnetic field values for each of 8 seconds, obtained from the DE-1 MAG experiment data. CHANNEL_A: 16 minor frame words for each of 8 seconds. Housekeeping and status data. CHANNEL_B: 512 values of accumulated count data from the RIMS radial head high mass channel. CHANNEL_C: 512 values of accumulated count data from the RIMS radial head low mass channel. CHANNEL_F: 512 values of accumulated count data from the radial head electrometer. CHANNEL_D: 512 values of count data from the +Z head. The data loaded alternates between the low and high mass channels. Initial and alternate configuration is set by minor mode A command. CHANNEL_E: 512 values of count data from the -Z head. The data loaded alternates between the low and high mass channels. Initial and alternate configurations is set by minor mode A command. FORMAT_APPLY_SCOPE: This format applies to all the fields under the RIMSMAF directory. UTILITY_TO_DECOMPRESS_DATA: The utility is included in the MAINSOURCE subdirectory of the SOFTWARE directory. UTILITY_APPLY_SCOPE: The decompress utility applies to all files under the RIMSMAF directory.