PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 122 FILE_RECORDS = 4188 ^SHADR_HEADER_TABLE = ("GTM090AA.SHA",1) ^SHADR_COEFFICIENTS_TABLE = ("GTM090AA.SHA",3) INSTRUMENT_HOST_NAME = "MARS GLOBAL SURVEYOR" TARGET_NAME = MARS INSTRUMENT_NAME = "MARS ORBITER LASER ALTIMETER" DATA_SET_ID = "MGS-M-MOLA-5-SHADR-V1.0" OBSERVATION_TYPE = "TOPOGRAPHY MODEL" ORIGINAL_PRODUCT_ID = "mars.shape" PRODUCT_ID = "GTM090AA.SHA" PRODUCT_RELEASE_DATE = 2000-12-31 DESCRIPTION = " This file contains coefficients and related data for a spherical harmonic model of the shape of Mars. Input data are from the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor (MGS) spacecraft. Coordinate system is IAU 1991 (Davies et al., Celestial Mechanics and Dynamical Astronomy, 53, 377-397, 1992), areocentric, with longitudes measured positive east. When evaluated, the model gives absolute radius from Mars center of mass in meters. The model is a numerical transform of planetary radius values from the MOLA 0.5-degree gridded data set DATA_SET_ID = 'MGS-M-MOLA-5-IEGDR-L3-V2.0' PRODUCT_ID = 'MOLA-IEG0062R.IMG' into spherical harmonics using Simpson's Rule quadrature. The gridded data set included all MOLA nadir observations from the Orbit Insertion phase, plus Mapping Phase nadir observations from the beginning of mapping through the end of December 1999. Additionally, off-nadir observations of the north pole were included from 87 N latitude and northward, taken during the spring of 1998, and of both poles taken in July of 1999, from 87 N and S to the poles. Orbits 355 and 358 of the Orbit Insertion Phase and parts of orbits 10709 through 10716, inclusive, of the Mapping Phase were excluded because solutions for these orbits were deemed to be poor. (Note: subtract 10000 from a MOLA mapping phase orbit number to determine the equivalent MGS Project orbit number.) Also excluded were shots more than 1 degree off-nadir except as noted above), channel 4 returns, and any returns not classified as ground returns, e.g. clouds or noise, according to the SHOT_CLASSIFICATION_CODE. A total of approximately 123 million observations are represented. Further improvements to the model are expected as additional MGS data are incorporated. This product is a set of two ASCII tables: a header table and a coefficients table. Definitions of the tables follow. This Mars topography model was produced under the direction of D.E. Smith of the MGS MOLA Team." START_TIME = 1997-09-15T19:10:00 STOP_TIME = 1999-12-31T23:59:59 PRODUCT_CREATION_TIME = 2000-11-16T00:00:00 PRODUCER_FULL_NAME = "GREG NEUMANN" PRODUCER_INSTITUTION_NAME = "GODDARD SPACE FLIGHT CENTER" PRODUCT_VERSION_TYPE = "PRELIMINARY" PRODUCER_ID = "MGS MOLA" SOFTWARE_NAME = "UNK;UNK" OBJECT = SHADR_HEADER_TABLE ROWS = 1 COLUMNS = 8 ROW_BYTES = 137 ROW_SUFFIX_BYTES = 107 INTERCHANGE_FORMAT = ASCII DESCRIPTION = "The SHADR header includes descriptive information about the spherical harmonic coefficients which follow in SHADR_COEFFICIENTS_TABLE. The header consists of a single record of eight (delimited) data columns requiring 137 bytes, a pad of 105 unspecified ASCII characters, an ASCII carriage-return, and an ASCII line-feed." OBJECT = COLUMN NAME = "REFERENCE RADIUS" DATA_TYPE = ASCII_REAL START_BYTE = 1 BYTES = 23 FORMAT = "E23.16" UNIT = "KILOMETER" DESCRIPTION = "A nominal value for the equatorial radius. The model gives absolute radius directly, so REFERENCE RADIUS is not needed when using the model." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "CONSTANT" DATA_TYPE = ASCII_REAL START_BYTE = 25 BYTES = 23 FORMAT = "E23.16" UNIT = "N/A" DESCRIPTION = "For a gravity field model the assumed gravitational constant GM in km cubed per seconds squared for the planet. For a topography model, set to 1." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "UNCERTAINTY IN CONSTANT" DATA_TYPE = ASCII_REAL START_BYTE = 49 BYTES = 23 FORMAT = "E23.16" UNIT = "N/A" DESCRIPTION = "For a gravity field model the uncertainty in the gravitational constant GM in km cubed per seconds squared for the planet (or, set to 0 if not known). For a topography model, set to 0." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "DEGREE OF FIELD" DATA_TYPE = ASCII_INTEGER START_BYTE = 73 BYTES = 5 FORMAT = "I5" UNIT = "N/A" DESCRIPTION = "Degree of the model field." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "ORDER OF FIELD" DATA_TYPE = ASCII_INTEGER START_BYTE = 79 BYTES = 5 FORMAT = "I5" UNIT = "N/A" DESCRIPTION = "Order of the model field." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "NORMALIZATION STATE" DATA_TYPE = ASCII_INTEGER START_BYTE = 85 BYTES = 5 FORMAT = "I5" UNIT = "N/A" DESCRIPTION = "The normalization indicator. For gravity field: 0 coefficients are unnormalized 1 coefficients are normalized 2 other." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "REFERENCE LONGITUDE" POSITIVE_LONGITUDE_DIRECTION = "EAST" DATA_TYPE = ASCII_REAL START_BYTE = 91 BYTES = 23 FORMAT = "E23.16" UNIT = "DEGREE" DESCRIPTION = "The reference longitude for the spherical harmonic expansion; normally 0." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "REFERENCE LATITUDE" DATA_TYPE = ASCII_REAL START_BYTE = 115 BYTES = 23 FORMAT = "E23.16" UNIT = "DEGREE" DESCRIPTION = "The reference latitude for the spherical harmonic expansion; normally 0." END_OBJECT = COLUMN END_OBJECT = SHADR_HEADER_TABLE OBJECT = SHADR_COEFFICIENTS_TABLE ROWS = 4186 COLUMNS = 6 ROW_BYTES = 107 ROW_SUFFIX_BYTES = 15 INTERCHANGE_FORMAT = ASCII DESCRIPTION = "The SHADR coefficients table contains the coefficients for the spherical harmonic model. Each row in the table contains the degree index m, the order index n, the coefficients Cmn and Smn, and the uncertainties in Cmn and Smn. The (delimited) data require 107 ASCII characters; these are followed by a pad of 13 unspecified ASCII characters, an ASCII carriage-return, and an ASCII line-feed. When evaluated, the model gives absolute radius from Mars center of mass in meters." OBJECT = COLUMN NAME = "COEFFICIENT DEGREE" DATA_TYPE = ASCII_INTEGER START_BYTE = 1 BYTES = 5 FORMAT = "I5" UNIT = "N/A" DESCRIPTION = "The degree index m of the C and S coefficients in this record." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "COEFFICIENT ORDER" DATA_TYPE = ASCII_INTEGER START_BYTE = 7 BYTES = 5 FORMAT = "I5" UNIT = "N/A" DESCRIPTION = "The order index n of the C and S coefficients in this record." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "C" DATA_TYPE = ASCII_REAL START_BYTE = 13 BYTES = 23 FORMAT = "E23.16" UNIT = "N/A" DESCRIPTION = "The coefficient Cmn for this spherical harmonic model." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "S" DATA_TYPE = ASCII_REAL START_BYTE = 37 BYTES = 23 FORMAT = "E23.16" UNIT = "N/A" DESCRIPTION = "The coefficient Smn for this spherical harmonic model." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "C UNCERTAINTY" DATA_TYPE = ASCII_REAL START_BYTE = 61 BYTES = 23 FORMAT = "E23.16" UNIT = "N/A" DESCRIPTION = "The uncertainty in the coefficient Cmn for this spherical harmonic model." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "S UNCERTAINTY" DATA_TYPE = ASCII_REAL START_BYTE = 85 BYTES = 23 FORMAT = "E23.16" UNIT = "N/A" DESCRIPTION = "The uncertainty in the coefficient Smn for this spherical harmonic model." END_OBJECT = COLUMN END_OBJECT = SHADR_COEFFICIENTS_TABLE END