PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 44 FILE_RECORDS = 1036 ^SHADR_HEADER_TABLE = ("NLRG016A.SHA",1) ^SHADR_COVARIANCE_TABLE = ("NLRG016A.SHA",2) SPACECRAFT_NAME = "NEAR EARTH ASTEROID RENDEZVOUS" TARGET_NAME = EROS INSTRUMENT_NAME = "NEAR LASER RANGEFINDER" DATA_SET_ID = "NEAR-A-NLR-6-EROS-MAPS-MODELS-V1.0" OBSERVATION_TYPE = "GRAVITY MODEL COVARIANCE" PRODUCT_ID = "NLRG016A.TAB" PRODUCT_RELEASE_DATE = 2001-08-31 DESCRIPTION = " This file contains covariances for coefficients of a spherical harmonic model of the gravity potential of Eros. The field is complete to degree and order 16, but covariances are given to degree and order 6. Input data are from the NEAR Laser Rangefinder (NLR) on the NEAR-Shoemaker (NEAR) spacecraft, together with two-way Doppler and range data from radio tracking. Coordinate system is given by the project-supplied orientation SPICE files, with longitudes measured positive east. When evaluated, the model gives gravitational potential of Eros. The potential model is the solution NLR393V3, from the orbit determination and parameter estimation program GEODYN/SOLVE. This software integrates the equations of motion of spacecraft using force models, and estimates the potential field of celestial bodies and other parameters. This product is an ASCII table, one row for each pair of coefficient entries. The table represents a full covariance matrix, with 45 rows by 45 columns. Each row or column represents one of the coefficients of NLRG016A.SHA, starting with the C(2,0) coefficient and ending with S(6,6). A covariance matrix is symmetric, so only the upper triangle is given. The gravity model was produced under the direction of D.E. Smith of NASA-Goddard Space Flight Center." START_TIME = 2000-03-05T00:00:04 STOP_TIME = 2001-02-12T19:42:43 PRODUCT_CREATION_TIME = 2000-06-06T18:22:00 PRODUCER_FULL_NAME = "MARK TORRENCE" PRODUCER_INSTITUTION_NAME = "GODDARD SPACE FLIGHT CENTER" PRODUCT_VERSION_TYPE = "PRELIMINARY" PRODUCER_ID = "NLR SCIENCE TEAM" SOFTWARE_NAME = "GEODYN/SOLVE" OBJECT = SHADR_HEADER_TABLE ROWS = 1 COLUMNS = 5 ROW_BYTES = 44 INTERCHANGE_FORMAT = ASCII DESCRIPTION = "The SHADR header includes descriptive information about the spherical harmonic model. The header consists of a single record of five data columns requiring 42 bytes, an ASCII carriage-return, and an ASCII line-feed." OBJECT = COLUMN NAME = "DEGREE OF FIELD" DATA_TYPE = ASCII_INTEGER START_BYTE = 1 BYTES = 5 FORMAT = "I5" DESCRIPTION = "Degree of the model field" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "ORDER OF FIELD" DATA_TYPE = ASCII_INTEGER START_BYTE = 6 BYTES = 5 FORMAT = "I5" DESCRIPTION = "Order of the model field" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "REFERENCE RADIUS" DATA_TYPE = ASCII_REAL START_BYTE = 11 BYTES = 10 FORMAT = "E10.2" UNIT = "METER" DESCRIPTION = "A normalization value for the equatorial radius" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "CONSTANT" DATA_TYPE = ASCII_REAL START_BYTE = 21 BYTES = 20 FORMAT = "E20.11" UNIT = "METERS CUBED PER SECONDS SQUARED" DESCRIPTION = "For a gravity field model the assumed gravitational constant GM in meters cubed per seconds squared for the planet. For a topography model, set to 1." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "NORMALIZATION STATE" DATA_TYPE = ASCII_INTEGER START_BYTE = 41 BYTES = 2 FORMAT = "I2" DESCRIPTION = "The normalization indicator. For gravity field: 0 coefficients are unnormalized 1 coefficients are normalized 2 other." END_OBJECT = COLUMN END_OBJECT = SHADR_HEADER_TABLE OBJECT = SHADR_COVARIANCE_TABLE ROWS = 1035 COLUMNS = 7 ROW_BYTES = 44 INTERCHANGE_FORMAT = ASCII DESCRIPTION = "The SHADR covariance table contains the coefficient covariance for the spherical harmonic model. For each degree index m, order index n, and coefficient Cmn or Smn, the formal covariance of (C,S)mn with any other coefficient is given. The space-delimited data require 42 ASCII characters; these are followed an ASCII carriage-return, and an ASCII line-feed." OBJECT = COLUMN NAME = "COEFFICIENT TYPE 1" DATA_TYPE = CHARACTER START_BYTE = 1 BYTES = 1 FORMAT = "A1" DESCRIPTION = "The coefficient type (C or S) of the first coefficient entry in this record" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "COEFFICIENT DEGREE 1" DATA_TYPE = ASCII_INTEGER START_BYTE = 2 BYTES = 4 FORMAT = "I4" DESCRIPTION = "The degree index m of the first C or S coefficient in this record" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "COEFFICIENT ORDER 1" DATA_TYPE = ASCII_INTEGER START_BYTE = 6 BYTES = 3 FORMAT = "I3" DESCRIPTION = "The order index n of the first C or S coefficient in this record" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "COEFFICIENT TYPE 2" DATA_TYPE = CHARACTER START_BYTE = 11 BYTES = 1 FORMAT = "A1" DESCRIPTION = "The coefficient type (C or S) of the second coefficient entry in this record" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "COEFFICIENT DEGREE 2" DATA_TYPE = ASCII_INTEGER START_BYTE = 12 BYTES = 4 FORMAT = "I4" DESCRIPTION = "The degree index m of the second C or S coefficient entry in this record" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "COEFFICIENT ORDER 2" DATA_TYPE = ASCII_INTEGER START_BYTE = 16 BYTES = 3 FORMAT = "I3" DESCRIPTION = "The order index n of the second C or S coefficient entry in this record" END_OBJECT = COLUMN OBJECT = COLUMN NAME = "C" DATA_TYPE = ASCII_REAL START_BYTE = 19 BYTES = 24 FORMAT = "E24.15" DESCRIPTION = "The covariance (C,S)m1n1(C,S)m2n2 of the spherical harmonic model" END_OBJECT = COLUMN END_OBJECT = SHADR_COVARIANCE_TABLE END