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MOLA Precision Radiometry Data Record (PRDR)

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PRDR – Precision Radiometry Data Record

 

Instrument: Mars Orbiter Laser Altimeter

PDS Data Set ID: MGS-M-MOLA-3-PRDR-L1A-V1.0

For more information about MOLA PRDR products, see the Data Set Catalog File and “Mars 1064-nm Spectral Radiance Measurements from the Receiver Noise Response of the Mars Orbiter Laser Altimeter”.

 

The Mars Orbiter Laser Altimeter (MOLA) Precision Radiometry Data Record (PRDR) data products contain MOLA science mode telemetry data that has been converted to engineering and physical units.  MOLA has two radiometric measurements:  the active measurement of transmitted and reflected laser pulse energy, and the passive measurement of reflected solar illumination.  The passive radiometry measurement is accomplished in a novel fashion by monitoring the noise density at the output of the photodetector and measurements provide images of Mars at 1064-nm wavelength over a 2-nm bandwidth with sub-km spatial resolution and 2% or better precision under full illumination.

 

Contained in a PRDR are range value, target position, and the planetary radius at the half-frame mid-point, interpolated from precision orbit data, spacecraft attitude data, and a MOLA shape model of Mars at 1/16 degree per pixel resolution.  Also included are solar illumination data and season.  These data are for convenience in interpretation and don’t not constitute independent planetometric data.  There are 10 radiometric values or ‘shots’ in each half-frame.  The location of individual shots may be obtained by interpolation for a pair of half-frames via the generic formula:

 

shot_location = x * mid_pt_location1 + (1-x) * mid_pt_location2,

where x = (shot-5.5)/10 for half-frame 1,

and x = (shot-15.5)/10 for half frame 2

 

There are two types of PRDR products:  radiometry data from when MOLA was in altimetry mode and radiometry data from when MOLA was in precision radiometer mode.

 

MOLA PRDR products have the following file names:

Amnnnnne.TAB (with detached PDS label)

where:

m = MOLA mode identifier

P = altimetry mode

R = precision radiometer mode

nnnnn = orbit number; for products from the Mapping Phase, this is the orbit number plus 10000

e = product edition number or letter

 

In ODE, PRDR products have the following product IDs:

MOLA-AMNNNNNE.TAB