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 <km>"
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 <km>"
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 <km>"
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 <km/s>"
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 <km/s>"
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 <km/s>"
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 <km>"
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 <km>"
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 <km>"
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 <km/s>"
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 <km/s>"
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 <km/s>"
END_OBJECT = COLUMN
END_OBJECT = TABLE