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/****************************************************************************/ /* This structure describes the format of the */ /* header record of the ephemeris data file of the Pioneer Venus Orbiter */ /* (PVO) Supplementary Experimental Data Record (SEDR). This record */ /* contains information describing temporal attributes of the ephemeris */ /* data records. The following is an overview in tabular form of the */ /* ephemeris header record: */ /* */ /* +----+----------------------------------------+ */ /* | |BITS --❯ | */ /* +----+----------------------------------------+ */ /* | | 111 1111 1112 2222 2222 2333 | */ /* | |1234 5678 9012 3456 7890 1234 5678 9012 | */ /* +----+----------------------------------------+ */ /* |WD 1|*LH WD | */ /* | 2| Number Of Logical Records In This File | */ /* | 3| (SPARE) | S/C ID | */ /* | 4| ORBIT NUMBER | */ /* | 5| START YEAR | START DOY | */ /* | 6| START MILLISECONDS OF DATA | */ /* | 7| STOP YEAR | STOP DOY | */ /* | 8| STOP MILLISECONDS OF DATA | */ /* | 9| (SPARE) | */ /* | 10| (SPARE) | */ /* | .| . | */ /* | .| . | */ /* | .| . | */ /* | 283| (SPARE) | */ /* | 284| (SPARE) | */ /* +----+----------------------------------------+ */ /* */ /* WORD 1 OF RECORD 1 IS LOGICAL HEADER WORD */ /* */ /* *LH WD = LOGICAL HEADER WORD */ /* DATA FORMAT = BINARY */ /* BITS 1 - 11 = PHYSICAL RECORD LENGTH = 284 WORDS */ /* BITS 12 - 22 = LOGICAL RECORD LENGTH = 284 WORDS */ /* BITS 23 - 27 = LOGICAL RECORDS PER PHYSICAL */ /* RECORD = 1 */ /* BITS 28 - 32 = FILE ID = 6 */ /****************************************************************************/ /* Table format description begins here. */ /****************************************************************************/ OBJECT = COLUMN NAME = "LOGICAL HEADER WORD" DATA_TYPE = "MSB BIT STRING" START_BYTE = 1 BYTES = 4 DESCRIPTION = "This object contains the 4 byte long Logical Header Word (LHWD) of the spacecraft ephemeris data file." OBJECT = BIT_COLUMN NAME = "PHYSICAL RECORD LENGTH" BIT_DATA_TYPE = "MSB UNSIGNED INTEGER" START_BIT = 1 BITS = 11 DESCRIPTION = "This object contains the physical record length of each data record in the ephemeris data file in 4 byte words. The value of this object is always 284." END_OBJECT = BIT_COLUMN OBJECT = BIT_COLUMN NAME = "LOGICAL RECORD LENGTH" BIT_DATA_TYPE = "MSB UNSIGNED INTEGER" START_BIT = 12 BITS = 11 DESCRIPTION = "This object contains the logical record length of each data record in the ephemeris data file in 4 byte words. The value of this object is always 284." END_OBJECT = BIT_COLUMN OBJECT = BIT_COLUMN NAME = "LOGICAL RECORDS PER PHYSICAL RECORD" BIT_DATA_TYPE = "MSB UNSIGNED INTEGER" START_BIT = 23 BITS = 5 DESCRIPTION = "This object contains the number of logical records contained in each physical record in the ephemeris data file. The value of this object is always 1." END_OBJECT = BIT_COLUMN OBJECT = BIT_COLUMN NAME = "FILE IDENTIFIER" BIT_DATA_TYPE = "MSB UNSIGNED INTEGER" START_BIT = 28 BITS = 5 DESCRIPTION = "This object contains the magnetic tape file number on the SEDR tape of the ephemeris data file. The value of this object is always 6." END_OBJECT = BIT_COLUMN END_OBJECT = COLUMN OBJECT = COLUMN NAME = "NUMBER OF LOGICAL RECORDS IN THIS FILE" DATA_TYPE = "MSB INTEGER" START_BYTE = 5 BYTES = 4 DESCRIPTION = "This object contains the number of logical data records in this ephemeris data file." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SHORT_SPARE DATA_TYPE = "MSB INTEGER" START_BYTE = 9 BYTES = 2 DESCRIPTION = "This object contains a spare (empty) value." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SPACECRAFT ID" DATA_TYPE = "MSB INTEGER" START_BYTE = 11 BYTES = 2 DESCRIPTION = "This object contains the spacecraft identification number for the Pioneer Venus Orbiter. The value of this object is always 12." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "ORBIT NUMBER" DATA_TYPE = "MSB INTEGER" START_BYTE = 13 BYTES = 4 NOTE = "This object contains the orbit number of the Pioneer Venus Orbiter for which this data was gathered." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "START YEAR OF DATA" DATA_TYPE = "MSB INTEGER" START_BYTE = 17 BYTES = 2 DESCRIPTION = "This object contains the four digit year for the first data point in this ephemeris data file." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "START DAY OF YEAR OF DATA" DATA_TYPE = "MSB INTEGER" START_BYTE = 19 BYTES = 2 DESCRIPTION = "This object contains the three digit day of year, ranging from 1 to 366, for the first data point in this ephemeris data file." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "START MILLISECONDS OF DAY OF DATA" DATA_TYPE = "IBM REAL" START_BYTE = 21 BYTES = 4 DESCRIPTION = "This object contains the milliseconds of the day, where midnight is 0.00, for the first data point in this ephemeris data file." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "STOP YEAR OF DATA" DATA_TYPE = "MSB INTEGER" START_BYTE = 25 BYTES = 2 DESCRIPTION = "This object contains the four digit year for the last data point in this ephemeris data file." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "STOP DAY OF YEAR OF DATA" DATA_TYPE = "MSB INTEGER" START_BYTE = 27 BYTES = 2 DESCRIPTION = "This object contains the three digit day of year, ranging from 1 to 366, for the last data point in this ephemeris data file." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "STOP MILLISECONDS OF DAY OF DATA" DATA_TYPE = "IBM REAL" START_BYTE = 29 BYTES = 4 DESCRIPTION = "This object contains the milliseconds of the day, where midnight is 0.00, for the last data point in this ephemeris data file." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SPARES" DATA_TYPE = "IBM REAL" START_BYTE = 33 BYTES = 4 ITEMS = 276 DESCRIPTION = "This object contains 276 spare (empty) values." END_OBJECT = COLUMN |