SHARAD .dat file read

[Andy]

Dear all,

I have a queation that how to read the SHARAD data file with extension .dat such as r_2501901_001_ss19_700_a.dat with r_2501901_001_ss19_700_a.lbl for description, in order to view the 2-D radargrams. The content of this .dat file may be consisted of characters (header of file) and ASCII (radar observations with rows and colums ). This file is download from this link http://ode.rsl.wustl.edu/mars/indexproductpage.aspx?product_idgeo=19642615

Whether the given JPEG radargrams is for showing the radar data which have been compressed and surface-clutter suppression or not?

 In addition, i can't find the MARSIS orbit 2682 data, maybe the PDS and ESA all didn't provide these data for users or i didn't find the right place to get data.

Thank you very much!

 

Best Regards,

Andy

 

[Susie Slavney]

The SHARAD data in the file you mentioned are stored as a binary table, not ASCII. The format is described in the PDS label file, here:

http://pds-geosciences.wustl.edu/mro/mro-m-sharad-4-rdr-v1/mrosh_1002/data/rdr25xxx/rdr2501901/r_2501901_001_ss19_700_a.lbl

and in the format file http://pds-geosciences.wustl.edu/mro/mro-m-sharad-4-rdr-v1/mrosh_1002/label/rdr.fmt. It is also described in the SHARAD Reduced Data Record Software Interface Specification (http://pds-geosciences.wustl.edu/mro/mro-m-sharad-4-rdr-v1/mrosh_1002/document/rdrsis.pdf). In particular, see section 4.2, Data Product Overview, and section 5.1, Data Product Structure and Organization.

 

In answer to the question about surface clutter, section 4.2 warns that the data "may contain artifacts due to off-nadir surface reflections, the so-called clutter...". So no, the clutter has not been removed from the data file.The JPEG browse image for this data file is here:

http://pds-geosciences.wustl.edu/mro/mro-m-sharad-4-rdr-v1/mrosh_1002/browse/rdr25xxx/rdr2501901/r_2501901_001_ss19_700_a_b.jpg.

The label file in the same directory explains how the data were processed to create the JPEG image:

http://pds-geosciences.wustl.edu/mro/mro-m-sharad-4-rdr-v1/mrosh_1002/browse/rdr25xxx/rdr2501901/r_2501901_001_ss19_700_a_b.lbl

 

There are no MARSIS Reduced Data Records for orbit 2682 in PDS. Reduced data only through orbit 2418 have been delivered by the MARSIS team to PDS.There are some raw data products for this orbit in http://pds-geosciences.wustl.edu/mex/mex-m-marsis-2-edr-ext1-v1/mexmde_1002/data/edr268x/.

[Andy]

Dear Susie Slavney,

Thanks for your answer and help.

The SHARAD orbit 6830 (R_0683001_001_SS19_700_A)  which can be found in http://ode.rsl.wustl.edu/mars/indexproductpage.aspx?product_idgeo=12028402 is overflown the LDAs in middle latitude of Mars, whether this orbit radar data has been processed including surface clutter suppression and give the final 2-D radargram image without surface off nadir clutters or not? 

What are the main differences between the Reduced Data Record (RDR) and Experimental Data Record (EDR) or raw data? As i know that the surface cross-track clutters are removed on board by dipole/monopole antennas, therefore the raw data should not contian the surface cross-track clutters. That is to say that the only efficent radar data processing techniques will include SAR techiniques to remove the along track surface off-nadir clutters, which processing is applied on ground.

whether my understandig is right or not?

Return to my question that whether the given radargram image describe the processed radar data derived by raw data which is proceed including just Doppler filtering, dipole/monopole antenna, dual-frequency techniques or not?

 

 

Best Regards,

Andy