This file describes the format of the ORPA RDR orbit data files. The structure is a table of records and columns. Within the table there are a variable number of tables. The outermost table represents the orbit, whereas the innermost tables represent each individual sweep within the orbit. Furthermore, each sweep table consists 6 tables. Each file consists of a file header table (one record table) followed by groups of data (tables), each group representing a sweep. Each sweep section is further divided into its header (one record table), a header for the data (one record table which tells how many records of data there will be), the data (table), the first and last data (two record table), a header for the SEDR data (one record table which tells how many records of SEDR data there will be), and the SEDR data (table). Because there is a variable number of records for the data and SEDR data, the current PDS standards could not correctly describe the data files. Therefore, this document uses the same format as PDS labels but does not comply with the standards. For summary purposes, there are two other files, RDR_DATA.IDX and SWEEP.IDX. included in each data directory. The first, RDR_DATA.IDX summarizes each orbit within the directory by the number of sweeps, periapsis, file records, start time, and stop times for each orbit. The second file, SWEEP.IDX summarizes each sweep within each orbit by the number of records of data, number of peaks, number of records of SEDR data, start time and stop time for each sweep. /* Data Object Structure ORBIT FILE */ /******************************************************************************/ /* */ /* ROW /____________________\ */ /* 1 | 40-byte File Header| */ /* ---------------------- */ /* */ /* /_____________________________________\ */ /* | | */ /* | ************************ | */ /* 2 | * 10-byte Sweep Header * | \ */ /* | ************************ | \ */ /* | | \ */ /* | ********************************** | \ */ /* | * 5-byte Data Header (NDP incl.) * | \ */ /* | ********************************** | \ */ /* | | \ */ /* | ******************** | \ */ /* . | * 47-byte Data * \ | \ */ /* | *------------------* NDP records | \ */ /* | * ... * / | this section */ /* | ******************** | is */ /* | | repeated for */ /* | ******************** | each sweep */ /* | * 47-byte 1st Data * | in the orbit */ /* | *------------------* | / */ /* | * 47-byte Last Data* | / */ /* | *------------------* | / */ /* | ******************** | / */ /* | | / */ /* | *********************************** | / */ /* | * 3-byte SEDR Header (NRP incl.) * | / */ /* | *********************************** | / */ /* | | / */ /* | ********************** | / */ /* | * 71-byte SEDR Data * \ | / */ /* | *--------------------* NRP | */ /* | * .... * /records | */ /* | ********************** | */ /* EOF |_____________________________________| */ /* */ /******************************************************************************/ /* File Header Structure */ /******************************************************************************/ /* */ /* ---------------------------------------------- */ /* || ORBIT || TIME || DATE || PERIAPSIS || DOY | */ /* ---------------------------------------------- */ /* 1 4 1 10 1 10 1 8 1 3 = 40 bytes */ /* */ /* */ /******************************************************************************/ /* Data Object Descriptions */ OBJECT = TABLE NAME = 'FILE HEADER' INTERCHANGE_FORMAT = ASCII ROWS = 1 COLUMNS = 9 ROW_BYTES = 40 DESCRIPTION = "Header information for the file associated with a particular orbit and its sweeps. This table contains the orbit number, the time and date of processing, time of periapsis, and day of year." OBJECT = COLUMN NAME = ORBIT UNIT = 'N/A' DATA_TYPE = INTEGER START_BYTE = 2 BYTES = 4 DESCRIPTION = "Orbit number" END_OBJECT = COLUMN OBJECT = COLUMN NAME = TIME UNIT = 'N/A' DATA_TYPE = CHARACTER START_BYTE = 7 BYTES = 10 DESCRIPTION = "Time of processing for this orbit." END_OBJECT = COLUMN OBJECT = COLUMN NAME = DATE UNIT = 'N/A' DATA_TYPE = CHARACTER START_BYTE = 18 BYTES = 10 DESCRIPTION = "Date of processing for this orbit." END_OBJECT = COLUMN OBJECT = COLUMN NAME = PERIAPSIS UNIT = MS DATA_TYPE = INTEGER START_BYTE = 29 BYTES = 8 DESCRIPTION = "Time of periapsis for the orbit given in ms of day" END_OBJECT = COLUMN OBJECT = COLUMN NAME = DOY UNIT = 'N/A' DATA_TYPE = INTEGER START_BYTE = 38 BYTES = 3 DESCRIPTION = "Day of year where Jan 1 = 1." END_OBJECT = COLUMN END_OBJECT = TABLE /* Sweep Header Structure */ /******************************************************************************/ /* */ /* ----------------------------- */ /* || STATUS || #PEAKS || MODE | */ /* ----------------------------- */ /* 1 5 1 1 1 1 = 10 bytes */ /* */ /******************************************************************************/ OBJECT = TABLE NAME = 'SWEEP HEADER' INTERCHANGE_FORMAT = ASCII ROWS = 1 COLUMNS = 3 ROW_BYTES = 10 DESCRIPTION = "Header information for SEDR and Data for a specific sweep. This table contains status, number of peaks, and mode." OBJECT = COLUMN NAME = "STATUS" UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTES = 2 BYTES = 5 DESCRIPTION = "16 bit instrument configuration." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "PEAKS" UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTES = 8 BYTES = 1 DESCRIPTION = "Number of peaks (2 or 4 in peaks mode, 1 in I-V mode.)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "MODE" UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTES = 10 BYTES = 1 DESCRIPTION = "Instrument configuration parsed from the status word, STATUS." END_OBJECT = COLUMN END_OBJECT = TABLE /* Data Header Structure */ /******************************************************************************/ /* */ /* ----------------- */ /* || NDP || IQUAL | */ /* ----------------- */ /* 1 2 1 1 = 5 bytes */ /* */ /******************************************************************************/ OBJECT = TABLE NAME = 'DATA HEADER' INTERCHANGE_FORMAT = ASCII ROWS = 1 COLUMNS = 2 ROW_BYTES = 5 DESCRIPTION = "Header information for the Data for a specific sweep. Table contains NDP and the data quality indicator." OBJECT = COLUMN NAME = "NDP" UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTES = 2 BYTES = 2 DESCRIPTION = "Number of voltage steps stepped through by the instrument (represents number of SEDR data records)." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "IQUAL" UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTES = 5 BYTES = 1 DESCRIPTION = "Data quality indicator." END_OBJECT = COLUMN END_OBJECT = TABLE /* Data Structure */ /******************************************************************************/ /* */ /* -------------------------------------------------------------------------- */ /* || TIME || CUR || CUR-UNCRT || RANGE || FIRST || SECOND || STP | */ /* || DELAY|| || || || CUR-RETARD || CUR_RETARD || | */ /* -------------------------------------------------------------------------- */ /* || || || || . || || || | */ /* || || || || . || || || | */ /* -------------------------------------------------------------------------- */ /* || || || || . || || || | */ /* || || NOTE: This table has NDP records. || || | */ /* -------------------------------------------------------------------------- */ /* 1 3 1 11 1 9 1 1 1 7 1 7 1 2 */ /* = 47 bytes */ /* */ /******************************************************************************/ OBJECT = TABLE NAME = "RDR DATA" INTERCHANGE_FORMAT = ASCII ROWS = /* (The number is equal to the value */ /* of NDP in the DATA HEADER table) */ COLUMNS = 7 ROW_BYTES = 47 DESCRIPTION = "IV Sweep data. This sweep contains a Time delay from start of sweep, the current, the current uncertainty, Electrometer range, retarding voltage of 1st and 2nd current, and the step number." OBJECT = COLUMN NAME = 'TIME DELAY' UNIT = 'MSEC' DATA_TYPE = 'INTEGER' START_BYTE = 2 BYTES = 3 DESCRIPTION = "Time delay from 1st current in milliseconds" END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'CUR' UNIT = AMPS DATA_TYPE = 'FLOAT' START_BYTE = 6 BYTES = 11 DESCRIPTION = "Current (A)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'CUR-UNCRT' UNIT = AMPS DATA_TYPE = 'FLOAT' START_BYTE = 18 BYTES = 9 DESCRIPTION = "Current uncertainty (A)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'RANGE' UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTE = 28 BYTES = 1 DESCRIPTION = "Electrometer range." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'FIRST CUR_RETARD' UNIT = 'EV' DATA_TYPE = 'FLOAT' START_BYTE = 30 BYTES = 7 DESCRIPTION = "Retarding Voltage (V) of 1st current forming current difference in peaks mode, or retarding potential of current in I-V mode." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'SECOND CUR_RETARD' UNIT = 'EV' DATA_TYPE = 'FLOAT' START_BYTE = 38 BYTES = 7 DESCRIPTION = "Retarding Voltage (V) of 2nd current forming current difference in peaks mode, or retarding potential of current in I-V mode." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'STP' UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTE = 46 BYTES = 2 DESCRIPTION = "Step number." END_OBJECT = COLUMN END_OBJECT = TABLE /* 1st/Last Data Structure */ /******************************************************************************/ /* */ /* -------------------------------------------------------------------------- */ /* || TIME || CUR || CUR-UNCRT || RANGE || FIRST || SECOND || STP | */ /* || DELAY|| || || || CUR-RETARD || CUR_RETARD || | */ /* -------------------------------------------------------------------------- */ /* || TIME || CUR || CUR-UNCRT || RANGE || FIRST || SECOND || STP | */ /* || DELAY|| || || || CUR-RETARD || CUR_RETARD || | */ /* -------------------------------------------------------------------------- */ /* 1 3 1 11 1 9 1 1 1 7 1 7 1 2 */ /* = 47 bytes */ /* */ /******************************************************************************/ OBJECT = TABLE NAME = "FIRST/LAST RDR DATA" INTERCHANGE_FORMAT = ASCII ROWS = 2 COLUMNS = 7 ROW_BYTES = 47 DESCRIPTION = "IV Sweep first and last data. This sweep contains a Time delay from start of sweep, the current, the current uncertainty, Electrometer range, retarding voltage of 1st and 2nd current, and the step number." OBJECT = COLUMN NAME = 'TIME DELAY' UNIT = 'MSEC' DATA_TYPE = 'INTEGER' START_BYTE = 2 BYTES = 3 DESCRIPTION = "Time delay from 1st current in milliseconds" END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'CUR' UNIT = AMPS DATA_TYPE = 'FLOAT' START_BYTE = 6 BYTES = 11 DESCRIPTION = "Current (A)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'CUR-UNCRT' UNIT = AMPS DATA_TYPE = 'FLOAT' START_BYTE = 18 BYTES = 9 DESCRIPTION = "Current uncertainty (A)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'RANGE' UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTE = 28 BYTES = 1 DESCRIPTION = "Electrometer range." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'FIRST CUR_RETARD' UNIT = 'EV' DATA_TYPE = 'FLOAT' START_BYTE = 30 BYTES = 7 DESCRIPTION = "Retarding Voltage (V) of 1st current forming current difference in peaks mode, or retarding potential of current in I-V mode." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'STP' UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTE = 46 BYTES = 2 DESCRIPTION = "Step number." END_OBJECT = COLUMN END_OBJECT = TABLE /* SEDR Header Structure */ /******************************************************************************/ /* */ /* -------- */ /* || NRP | */ /* -------- */ /* 1 2 = 3 bytes */ /* */ /******************************************************************************/ OBJECT = TABLE NAME = 'SEDR HEADER' INTERCHANGE_FORMAT = ASCII ROWS = 1 COLUMNS = 1 ROW_BYTES = 3 DESCRIPTION = "Header information for the SEDR Data for a specific sweep." OBJECT = COLUMN NAME = "NRP" UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTES = 2 BYTES = 2 DESCRIPTION = "Number of spin periods in MSUTA (universal time in milliseconds) and EDUM() sets specifying possible time and position of sweep (represents number of Data Records)." END_OBJECT = COLUMN END_OBJECT = TABLE /* SEDR Data Structure */ /******************************************************************************/ /* */ /* -------------------------------------------------------------------------- */ /* || YEAR || DOY || TIME-MS || ROL || SPIN-PRD || SPIN X || SPIN Y || */ /* SPIN Z || V-SC X || V-SC Y || V-SC Z || VEL X || VEL Y || VEL Z || */ /* S_SC X || S_SC Y || S-SC Z || S-X || S-Y || S-Z */ /* -------------------------------------------------------------------------- */ /* || || || || || || || || */ /* || || || || || || || */ || || || || || */ /* -------------------------------------------------------------------------- */ /* || || || || || || || || */ /* || || || || || || || */ /* || NOTE: This table has NRP records. */ /* -------------------------------------------------------------------------- */ /* 1 4 1 3 1 8 1 7 1 6 1 11 1 11 1 */ /* 11 1 9 1 9 1 9 1 8 1 8 1 8 1 */ /* 12 1 12 1 12 1 8 1 8 1 8 */ /* 58 + 69 + 65 = 192 bytes */ /* */ /******************************************************************************/ OBJECT = TABLE NAME = "SEDR DATA" INTERCHANGE_FORMAT = ASCII ROWS = /* (The number is equal to the value of*/ /* NRP in the SEDR DATA HEADER table) */ COLUMNS = 17 ROW_BYTES = 192 DESCRIPTION = "This contains spacecraft ephemeris data and time stamp(s) for the sweep. This sweep contains a Year, day, time, roll, spin period, spin x-y-z, Venus-spacecraft position x-y-z, Venus-spacecraft, velocity x-y-z, Sun-spacecraft position x-y-z, and Sun-spacecraft velocity x-y-z." END_OBJECT = TABLE OBJECT = COLUMN NAME = 'YEAR' UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTE = 2 BYTES = 4 DESCRIPTION = "Year A.D. of sweep data." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'DOY' UNIT = 'NONE' DATA_TYPE = 'INTEGER' START_BYTE = 7 BYTES = 3 DESCRIPTION = "Day of year of sweep data where Jan 1 = 1." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'TIME-MS' UNIT = 'MS' DATA_TYPE = 'INTEGER' START_BYTE = 11 BYTES = 8 DESCRIPTION = "Universal time in milliseconds." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'ROLL' UNIT = 'DEGREE' DATA_TYPE = 'FLOAT' START_BYTE = 20 BYTES = 7 DESCRIPTION = "Roll angle (deg) in non-rotating spin coordinate system (NRSC)." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'SPIN-PRD' UNIT = 'SEC.DS' DATA_TYPE = 'FLOAT' START_BYTE = 28 BYTES = 6 DESCRIPTION = "Spin period (sec.ds)." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'SPIN-X' UNIT = 'NONE' DATA_TYPE = 'FLOAT' START_BYTE = 35 BYTES = 11 DESCRIPTION = "Attitude of spin axis, direction cosine to x axis in ecliptic coordinates." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'SPIN-Y' UNIT = 'NONE' DATA_TYPE = 'FLOAT' START_BYTE = 47 BYTES = 11 DESCRIPTION = "Attitude of spin axis, direction cosine to y axis in ecliptic coordinates." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'SPIN-Z' UNIT = 'NONE' DATA_TYPE = 'FLOAT' START_BYTE = 59 BYTES = 11 DESCRIPTION = "Attitude of spin axis, direction cosine to z axis in ecliptic coordinates." END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'V-SC X' UNIT = 'KM' DATA_TYPE = 'FLOAT' START_BYTE = 71 BYTES = 9 DESCRIPTION = "Venus-Spacecraft position vector X-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'V-SC Y' UNIT = 'KM' DATA_TYPE = 'FLOAT' START_BYTE = 81 BYTES = 9 DESCRIPTION = "Venus-Spacecraft position vector Y-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'V-SC Z' UNIT = 'KM' DATA_TYPE = 'FLOAT' START_BYTE = 91 BYTES = 9 DESCRIPTION = "Venus-Spacecraft position vector Z-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'VEL X' UNIT = 'KM/S' DATA_TYPE = 'FLOAT' START_BYTE = 101 BYTES = 8 DESCRIPTION = "Venus-Spacecraft velocity vector X-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'VEL Y' UNIT = 'KM/S' DATA_TYPE = 'FLOAT' START_BYTE = 110 BYTES = 8 DESCRIPTION = "Venus-Spacecraft velocity vector X-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'VEL Z' UNIT = 'KM/S' DATA_TYPE = 'FLOAT' START_BYTE = 119 BYTES = 8 DESCRIPTION = "Venus-Spacecraft velocity vector X-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'S_SC X' UNIT = 'KM' DATA_TYPE = 'FLOAT' START_BYTE = 128 BYTES = 12 DESCRIPTION = "Sun-Spacecraft position vector Z-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'S_SC Y' UNIT = 'KM' DATA_TYPE = 'FLOAT' START_BYTE = 141 BYTES = 12 DESCRIPTION = "Sun-Spacecraft position vector Z-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'S_SC Z' UNIT = 'KM' DATA_TYPE = 'FLOAT' START_BYTE = 154 BYTES = 12 DESCRIPTION = "Sun-Spacecraft position vector Z-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'V-SC VEL X' UNIT = 'KM/S' DATA_TYPE = 'FLOAT' START_BYTE = 167 BYTES = 8 DESCRIPTION = "Sun-Spacecraft velocity vector Z-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'V-SC VEL Y' UNIT = 'KM/S' DATA_TYPE = 'FLOAT' START_BYTE = 176 BYTES = 8 DESCRIPTION = "Sun-Spacecraft velocity vector Z-component in NRSC coordinates " END_OBJECT = COLUMN OBJECT = COLUMN NAME = 'V-SC VEL Z' UNIT = 'KM/S' DATA_TYPE = 'FLOAT' START_BYTE = 185 BYTES = 8 DESCRIPTION = "Sun-Spacecraft velocity vector Z-component in NRSC coordinates " END_OBJECT = COLUMN END_OBJECT = TABLE