PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 78 FILE_RECORDS = 215 ^TABLE = "RANGECAL.TAB" DATA_SET_ID = "MPF-M-RSS-1/5-RADIOTRACK-V1.0" PRODUCT_ID = "RANGECAL.TAB" SPACECRAFT_NAME = "MARS PATHFINDER" INSTRUMENT_ID = RSS TARGET_NAME = MARS PRODUCT_CREATION_TIME = 1998-01-08T01:00:00Z MISSION_PHASE_NAME = {"LANDER SURFACE MISSION", "LANDER EXTENDED MISSION"} ORBIT_NUMBER = "N/A" START_TIME = 1997-07-06T03:00:00Z STOP_TIME = 1997-09-25T06:00:00Z OBJECT = TABLE INTERCHANGE_FORMAT = ASCII ROWS = 215 COLUMNS = 10 ROW_BYTES = 78 ROW_SUFFIX_BYTES = 0 DESCRIPTION = "This table gives DSN station ranging calibrations recorded for each Mars Pathfinder tracking pass. These calibrations are included in the data on the ATDF files in the TDF directory, and have been applied to the ranging measurements included in the ODF files in the ODF directory, and also to the ASCII formatted data in the REDUCED directory. Sometimes it is helpful to see the calibrations that were applied, to investigate possible systematic effects in station instrumentation. Range is a measure of the round trip light time. Actually measured are the phases of a sub-harmonic of the uplink (DSN to spacecraft) carrier frequency. Using the 4th 'ranging component', round-trip light time is measured as the phase of a signal near 1 MHz. The wavelength is thus about 300 meters and is measured to about one part in one-thousand, or one 'range unit', which is approximately the distance traveled by light in one nano-second. Since the phase is ambiguous by an integer number of cycles, the range at this frequency would be ambiguous by an integer multiple of 300 meters. Additional sub-harmonics are usually measured so that relative coarse initial position knowledge can be used to resolve the ambiguity. Typically the 17th 'ranging component' is used, which has an ambiguity of about 2**(13) range units, or about 2500 kilometers. Usually a priori information on the spacecraft position allows the determination of position to this level. The station is calibrated by measuring a delay to a dummy device near the DSN antenna feed. The round-trip delay, or RNG-CAL, is measured in range units, and later subtracted from the spacecraft measured delay. The Z-CORR is a correction for the delay from the position of the dummy device to the feed of the antenna, and is measured in nanoseconds. The Z-CORR is usually constant unless the antenna feed is physically reconfigured. The RNG-CAL usually varies from pass to pass due to thermally-induced changes in cable lengths in the measurement apparatus. For more information, see [DSN 810-5]." OBJECT = COLUMN COLUMN_NUMBER = 1 NAME = "START DATE/TIME" DATA_TYPE = TIME START_BYTE = 1 BYTES = 17 UNIT = "N/A" DESCRIPTION = "Date/time for start of calibration" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 2 NAME = "STOP DATE/TIME" DATA_TYPE = TIME START_BYTE = 19 BYTES = 18 UNIT = "N/A" DESCRIPTION = "Date/time for end of calibration" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 3 NAME = "DSN STATION ID" DATA_TYPE = ASCII_INTEGER START_BYTE = 38 BYTES = 4 FORMAT = "I4" UNIT = "N/A" DESCRIPTION = "DSN station number" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 4 NAME = "QUALITY FLAG" DATA_TYPE = ASCII_INTEGER START_BYTE = 43 BYTES = 2 FORMAT = "I2" UNIT = "N/A" DESCRIPTION = "1 indicates nominal performance. Anything else indicates a measurement system error" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 5 NAME = "XMIT/RECEIVE TYPE" DATA_TYPE = ASCII_INTEGER START_BYTE = 46 BYTES = 2 FORMAT = "I2" UNIT = "N/A" DESCRIPTION = "Flag indicating transmitter/receiver type in use. 1 indicates Block 3 or Block 4 receiver and Transmitter. 2 indicates Block 3 or 4 transmitter and Block 5 receiver. 3 indicates indicates Block 5 xmitter/receiver. See [DSN 810-5]." END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 6 NAME = "NUMBER OF POINTS" DATA_TYPE = ASCII_INTEGER START_BYTE = 49 BYTES = 3 FORMAT = "I3" UNIT = "NONE" DESCRIPTION = "Number of measurements made in pass." END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 7 NAME = "Z-CORR" DATA_TYPE = ASCII_INTEGER START_BYTE = 53 BYTES = 7 FORMAT = "I7" UNIT = "NONE" DESCRIPTION = "Delay correction from fixed ranging transponder to antenna feed measured in hundredths of nanoseconds" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 8 NAME = "RNG-CAL" DATA_TYPE = ASCII_INTEGER START_BYTE = 61 BYTES = 9 FORMAT = "I9" UNIT = "NONE" DESCRIPTION = "Measured round-trip delay at station to fixed ranging transponder near the antenna feed, measured in units of 1/1024 of the ranging wavelength. The ranging frequency is 1/22 of the reference frequency (near 22 MHz) which is included for each range measurement, on the ODF or TDF file." END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 9 NAME = "HIGH COMPONENT" DATA_TYPE = ASCII_INTEGER START_BYTE = 71 BYTES = 2 FORMAT = "I2" UNIT = "NONE" DESCRIPTION = "Most precise (highest frequency) carrier subharmonic used for ranging" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 10 NAME = "LOW COMPONENT" DATA_TYPE = ASCII_INTEGER START_BYTE = 74 BYTES = 3 FORMAT = "I3" UNIT = "NONE" DESCRIPTION = "Least precise (lowest frequency) carrier subharmonic used for ranging" END_OBJECT = COLUMN END_OBJECT = TABLE END