urn:nasa:pds:magellan_gravity:gravity:shgj120u 1.0 1.20.0.0 Product_Observational Sjogren, William L. 1997 Coefficients and related data for a spherical harmonic model of the Venus gravity field. 2023-09-06 1.0 Product migrated to PDS4 from PDS3. Magellan Mission urn:nasa:pds:context:investigation:mission.magellan data_to_investigation Magellan Host urn:nasa:pds:context:instrument_host:spacecraft.mgn is_instrument_host Radio Science Subsystem Instrument urn:nasa:pds:context:instrument:mgn.rss is_instrument Venus Planet urn:nasa:pds:context:target:planet.venus data_to_target SHXDR 5758 15019 JET PROPULSION LABORATORY shgj120u.b01 1997-12-17T00:00:00.000 This file contains coefficients and related data for a spherical harmonic model of the Venus gravity field. Input data are from radio tracking of the Magellan spacecraft. This product is a set of binary tables: a header table, a names table, a coefficients table, and a covariance table. Definitions of the tables follow. This Magellan Venus gravity model is in the form of a Spherical Harmonics Binary Data Record (SHBDR). It has been produced by the Magellan Gravity Science Team at JPL under the direction of W.L. Sjogren. SHBDR Header Table 0 1 The SHBDR Header includes descriptive information about the spherical harmonic coefficients which follow in SHBDR_COEFFICIENTS_TABLE. The header consists of a single record of nine data columns requiring 56 bytes. The Header is followed by a pad of binary integer zeroes to ensure alignment with RECORD_BYTES. RECORD_BYTES = 512 9 0 56 reference radius 1 1 IEEE754LSBDouble 8 kilometer The assumed reference radius of the spherical planet. constant 2 9 IEEE754LSBDouble 8 For a gravity field model the gravitational constant GM in km cubed per seconds squared for the planet. For a topography model, set to 1 uncertainty in constant 3 17 IEEE754LSBDouble 8 For a gravity field model the uncertainty in the gravitational constant GM in km cubed per seconds squared for the planet. For a topography model, set to 0. degree of field 4 25 SignedLSB4 4 Degree of the model field. order of field 5 29 SignedLSB4 4 Order of the model field. normalization state 6 33 SignedLSB4 4 The normalization indicator. For gravity field: 0 coefficients are unnormalized 1 coefficients are normalized 2 other. number of names 7 37 SignedLSB4 4 Number of valid names in the SHBDR Names Table. Also, the number of valid coefficients in the SHBDR Coefficients Table. reference longitude 8 41 IEEE754LSBDouble 8 degree The reference longitude for the spherical harmonic expansion; normally 0. reference latitude 9 49 IEEE754LSBDouble 8 degree The reference latitude for the spherical harmonic expansion; normally 0. SHBDR Names Table 512 14638 The SHBDR Names Table contains names for the solution parameters (including gravity field coefficients) which will follow in SHBDR_COEFFICIENTS_TABLE. The order of the names in SHBDR_NAMES_TABLE corresponds identically to the order of the parameters in SHBDR_COEFFICIENTS_TABLE. Each coefficient name is of the form Cij or Sij where i is the degree of the coefficient and j is the order of the coefficient. Both indices are three- digit zero-filled right-justified ASCII character strings (for example, C010005 for the 10th degree 5th order C coefficient, or S002001 for the 2nd degree 1st order S coefficient). The eighth byte in the table is an ASCII blank used to ensure that the row length is equal to RECORD_BYTES. Names of other solution parameters are limited to 8 ASCII characters; if less than 8, they will be left-justified and padded with ASCII blanks. The Names Table itself will be padded with ASCII blanks, if necessary, so that its length is an integral multiple of RECORD_BYTES. RECORD_BYTES = 512 1 0 8 parameter name 1 1 ASCII_String 8 The name of the coefficient or other solution parameter, left- justified and padded with ASCII blanks (if needed) to 8 characters. SHBDR Coefficients Table 117760 14638 The SHBDR Coefficients Table contains the coefficients and other solution parameters for the spherical harmonic model. The order of the coefficients in this table corresponds exactly to the order of the coefficient and parameter names in SHBDR_NAMES_TABLE. The SHBDR Coefficients Table will be padded with double precision DATA_TYPE zeroes so that its total length is an integral multiple of RECORD_BYTES. RECORD_BYTES = 512 1 0 8 coefficient value 1 1 IEEE754LSBDouble 8 A coefficient Cij or Sij or other solution parameter as specified in the SHBDR Names Table. SHBDR Covariance Table 235008 107142841 The SHBDR Covariance Table contains the covariances for the spherical harmonic model coefficients and other solution parameters. The order of the covariances in this table is defined by the product of the SHBDR Names Table with its transpose, except that redundant terms are omitted on their second occurrence. The SHBDR Covariance Table will be padded with double precision DATA_TYPE zeroes so that its total length is an integral multiple of RECORD_BYTES. RECORD_BYTES = 512 1 0 8 covariance value 1 1 IEEE754LSBDouble 8 The covariance value for the coefficients and other solution parameters specified by the product of SHBDR_NAMES_TABLE with its transpose, after omitting redundant terms. shgj120u.lbl 0 PDS3 Original PDS3 label Carriage-Return Line-Feed