MGN RDRS Surface Characteristics Vector Data Record (SCVDR)
SCVDR – Surface Characteristics Vector Data Record
Instrument: Magellan Radar System
PDS3 Data Set ID: MGN-V-RDRS-5-SCVDR-V1.0 DOI: 10.17189/15225145
PDS4 Bundle: urn:nasa:pds:magellan_scvdr DOI: 10.17189/9xva-nd32
For more information about RDRS SCVDR products, see the SCVDR Data Set Description, Document Files, Software Interface Specification File (TXT).
The Radar System (RDRS) Surface Characteristics Vector Data Record (SCVDR) is an orbit-by-orbit reduction of Magellan scattering and emission measurements carried out at Stanford University. The SCVDR includes near-nadir scattering functions obtained by numerical inversion from altimetry (ALT) echoes, results (e.g. RMS surface slopes and Fresnel reflectivity) from fitting analytic functions to those inversions, scattering function segments at oblique incidence angles derived from synthetic aperture radar (SAR) echoes, and estimates of surface emissivity derived from thermal microwave radiometry (RAD) measurements. The SCVDR is one of several inputs to the Global Vector Data Record (GVDR), a gridded summary of scattering results, also produced at Stanford.
The objective in compiling the SCVDR is to obtain an accurate estimate of the surface backscattering function (sometimes called the specific backscatter function or “sigma-zero”) for Venus from the ALT, SAR, and RAD data types and to show its variation with incidence (polar) angle, azimuthal angle, and surface location.
For this Magellan SCVDR archive, a single PDS4 bundle (urn:nasa:pds:magellan_scvdr) has been defined, containing the data from the 49 PDS3 volumes (mg_2101- mg_2149). This bundle has seven data collections, one document collection, and one miscellaneous collection. The seven data collections of the PDS4 bundle are mixed together within the directory structure because the physical arrangement of data products is organized by spacecraft orbit. This organization is similar to that of the original CD-ROMs.
SCVDR includes data from several orbits. For each orbit, there are six files, grouped into six data collections as shown below:
|
File |
Product Type |
Description |
PDS4 Collection |
|
Altimetry Inversion File |
The ANF contains the results of inverting the time and frequency spectra of a single orbit of Magellan altimetry, from the ALT-EDR product, by means of the accompanying Geometry Matrix File (GMF). The ANF 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. |
Collection LID: urn:nasa:pds:magellan_scvdr:data_anf Link to collection inventory label |
|
|
Emissivity Data File |
The EDF contains measurements of the microwave emissivity of the Venus surface, obtained from the radiometer mode of the Magellan radar sensor. The EDF 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. |
Collection LID: urn:nasa:pds:magellan_scvdr:data_edf Link to collection inventory label |
|
|
Inversion Fit File |
The 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. |
Collection LID: urn:nasa:pds:magellan_scvdr:data_nff Link to collection inventory label |
|
|
Orbit Header File |
The OHF identifies the orbit number, time frame, and orbital geometry for one Magellan orbit. The OHF contains only a CCSD header, a keyword and value SFDU, and a binary header record SFDU. |
Collection LID: urn:nasa:pds:magellan_scvdr:data_ohf Link to collection inventory label |
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|
Oblique Sinusoidal Image File |
The OIF contains the results of fitting the radar backscatter cross-section measurements of a single Magellan orbit, from the oblique sinusoidal (polar) image file of the C-BIDR or F-BIDR product, to a quadratic function, along with a histogram of pixel values used in the fit. The OIF 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. |
Collection LID: urn:nasa:pds:magellan_scvdr:data_oif Link to collection inventory label |
|
|
Sinusoidal Image File |
The SIF contains the results of fitting the radar backscatter cross-section measurements of a single Magellan orbit, from the sinusoidal image file of the C-BIDR or F-BIDR product, to a quadratic function, along with a histogram of pixel values used in the fit. The SIF 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. |
Collection LID: urn:nasa:pds:magellan_scvdr:data_anf Link to collection inventory label |
Note:** - In the original PDS3 dataset, the Geometry Matrix Files (GMF) were contained in separate “geometry” directories on each PDS3 volume. In this PDS4 bundle, they are instead included with the other data files in the data directory. They are not listed as a single product type available to be searched in ODE, but are referenced by the ANF product in ODE's search result detail page.
RDRS SCVDR product subdirectories have the following directory names:
xxxx_yyyy
where:
xxxx = 4-digit decimal number denoting the value of the first orbit number for data in the subdirectory.
yyyy = 4-digit decimal number denoting the value of the last orbit number for data in the subdirectory.
RDRS SCVDR products have the following file names:
xxx0nnnn_v (with detached PDS label)
where:
xxx = product type
ANF = Altimetry inversion file
EDF = Emissivity data file
NNF = Inversion fit file
OHF = Orbit header file
OIF = Oblique sinusoidal image file
SIF = Sinusoidal image file
nnnn = 4-digit orbit number
v = 1-digit version number
In ODE, SCVDR products, which include all the files for one orbit, have the following product IDs:
anf0nnnn
edf0nnnn
nnf0nnnn
ohf0nnnn
oif0nnnn
sif0nnnn