urn:nasa:pds:magellan_scvdr:data_nff:nff04355 1.0 1.23.0.0 Product_Observational 2025-09-16 1.0 Initial PDS4 version 1992-03-09T01:21:50.064Z 1992-03-09T01:37:27.881Z Magellan Mission urn:nasa:pds:context:investigation:mission.magellan data_to_investigation The Magellan Spacecraft Host urn:nasa:pds:context:instrument_host:spacecraft.mgn is_instrument_host Magellan Spacecraft Radar System Instrument urn:nasa:pds:context:instrument:mgn.rdrs is_instrument Venus Planet urn:nasa:pds:context:target:planet.venus data_to_target SCVDR 1 4355 Mapping Cycle 3 mg_2145 urn:nasa:pds:magellan_scvdr:document:scvdr_sis data_to_document nff04355_1.dat 1994-10-11T06:00:47Z The Altimetry Inversion Fit File (NFF) contains the results of fitting the radar scattering cross sections contained in the accompanying Altimetry Inversion Data File to one or more theoretical models. The NFF contains a CCSD header, a keyword and value SFDU, a binary header record SFDU, and one or more binary data record SFDUs, sandwiched between starting and ending marker SFDUs.

0 20 7-Bit ASCII Text CCSD header.

20 368 7-Bit ASCII Text SFDU keyword label (K-type).

Altimetry Inversion Fit Header Table 388 1 The single binary NFF header record contains constants that describe the fitting process, algorithm IDs, and the maximum sizes of arrays in the NFF data records. 19 1 72 SFDU_AGGREGATE_HEADER 1 1 ASCII_String 20 'NJPL1I00000700000052', the number '0007' is registered with the NJPL SFDU authority as the 'Stanford Inversion Fit Header Record'. '00000052' signifies that the remainder of this SFDU is 52 bytes in length. ORBIT_NUMBER 2 21 UnsignedMSB4 4 The orbit number for the data to be fit. ORBIT_VERSION 3 25 UnsignedMSB4 4 The version number for the altimetry data file used in this processing. Obtained from the VERSION_ID keyword of the corresponding ALT-EDR Orbit Header File (Note: This turns out not to be a good indicator of the version of the data file; the Orbit Header File itself is rarely updated). SSLFIT_MAJOR_VERSION_NUMBER 4 29 UnsignedMSB2 2 The number of the major software version of Stanford program SSLFIT used to fit these data. SSLFIT_MINOR_VERSION_NUMBER 5 31 UnsignedMSB2 2 The number of the minor software version of Stanford program SSLFIT used to fit these data. ALTINV_MAJOR_VERSION_NUMBER 6 33 UnsignedMSB2 2 The number of the major software version of Stanford program ALTINV that produced the scattering function solutions. ALTINV_MINOR_VERSION_NUMBER 7 35 UnsignedMSB2 2 The number of the minor software version of Stanford program ALTINV that produced the scattering function solutions. ALT_MAJOR_VERSION_NUMBER 8 37 UnsignedMSB2 2 The number of the major software version of Stanford program ALT used to carry out the range-Doppler processing on these data. ALT_MINOR_VERSION_NUMBER 9 39 UnsignedMSB2 2 The number of the minor software version of Stanford program ALT used to carry out the range-Doppler processing on these data. NUMBER_OF_RECORDS_IN_FILE 10 41 UnsignedMSB4 4 The number of inversions (solutions for the surface scattering law) and hence, the number of fitted result records in this file; equal to NUMBER_OF_DATA_RECORDS. NUMBER_OF_SYNTHETIC_SCATTERING_LAWS 11 45 UnsignedMSB2 2 The number of synthetic scattering laws compared against the scattering solution; 'synthetic' scattering laws can include Hagfors, exponential, Gaussian, Rayleigh, and Muhleman. INVERSION_METHOD_ID 12 47 UnsignedByte 1 The identifier for inversion method (carried forward from corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). VARIANCE_ESTIMATION_METHOD_ID 13 48 UnsignedByte 1 The identifier for variance estimation technique (carried forward from the corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). CONSTRAINT_VARIANCE_METHOD_ID 14 49 UnsignedByte 1 The identifier for variance constraint technique (carried forward from the corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). THERMAL_NOISE_METHOD_ID 15 50 UnsignedByte 1 The identifier for thermal noise estimation technique (carried forward from corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). DOPPLER_ROTATION_METHOD_ID 16 51 UnsignedByte 1 The identifier for Doppler rotation technique (carried forward from the corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). RANGE_ECHO_PROCESSING_ID 17 52 UnsignedByte 1 The identifier for range echo processing technique (carried forward from the corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). MAXIMUM_ANGLE_METHOD_ID 18 53 UnsignedByte 1 The identifier for technique to set maximum incidence angle in solution (carried forward from corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). NON_DELTA_SPECTRAL_FILTER_FLAG 19 54 UnsignedByte 1 Set if Doppler spectrum was filtered before the inversion (carried forward from corresponding Altimetry Inversion Header Record; see Section 5.4.1 of the SCVDR SIS). 1 18 1 0 55 18 SPARE 1 1 UnsignedByte 1 Spare. Altimetry Inversion Fit Data Table 546 210 Each NFF data record contains the result of fitting a scattering function from the corresponding ANF data record to one or more scattering models. 3 2 212 SFDU_AGGREGATE_HEADER 1 1 ASCII_String 20 'NJPL1I0000080000nnnn', the number '0008' is registered with the NJPL SFDU authority as the 'Inversion Fit Data Record'. 'nnnn' is the length in bytes of the remainder of the SFDU, which varied from record to record in the original data file. After padding for PDS4 migration, nnnn = 192. FOOTPRINT_NUMBER 2 21 UnsignedMSB4 4 Starting from 1, the number of the Inversion Fit Data Record; equal to the Footprint Number FOOTPRINT_NUMBER in the corresponding Altimetry Inversion Data Record. NUMBER_OF_SCATTERING_LAWS 3 25 UnsignedMSB4 4 The number of synthetic scattering laws compared against the scattering solution; 'synthetic' scattering laws can include Hagfors, exponential, Gaussian, Rayleigh, and Muhleman. 1 4 1 0 29 4 SPARE 1 1 UnsignedByte 1 Spare. SCATTERING_LAW_FITS_CONTAINER 2 5 9 0 A collection of best fit scattering models to the observed scattering law in the SCATTERING_FUNCTION array of the corresponding ANF file. The fits are made using the formal ANF COVARIANCE_MATRIX. The number of repetitions is NUMBER_OF_SCATTERING_LAWS and each repetition contains the results of a single least-squares fit of the empirical scattering function to a particular scattering model. 33 180 SCATTERING_LAW_ID 1 1 ASCII_String 4 A 4-letter identifier for one of several analytic scattering functions which can be fitted to FR_SIG0. FLAG_FIELDS_FOR_FIT 2 5 UnsignedMSB4 4 Stanford Inversion Fit Record Flag Values. FIT_PARAMETER_1 3 9 IEEE754MSBSingle 4 Scattering law parameter #1. FIT_PARAMETER_1_VARIANCE 4 13 IEEE754MSBSingle 4 Variance in FIT_PARAMETER_1. FIT_PARAMETER_2 5 17 IEEE754MSBSingle 4 Scattering law parameter #2. FIT_PARAMETER_2_VARIANCE 6 21 IEEE754MSBSingle 4 Variance in FIT_PARAMETER_2. RMS_SLOPE 7 25 IEEE754MSBSingle 4 radians RMS Tilt for Fitted Function. RMS_SLOPE_VARIANCE 8 29 IEEE754MSBSingle 4 Variance of RMS_SLOPE. RESIDUAL_ERROR_IN_FIT 9 33 IEEE754MSBSingle 4 Residual between analytic function and scattering function from inversion of data for best choices of FIT_PARAMETER_1 and FIT_PARAMETER_2.