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I have obtained quad-polarized level 1b TerraSAR-X data from DLR. When I tried to read the data using PolSARpro, I understood that it is only capable of reading SSC format

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But my data is in MGD (Multilook Ground Detected format) which causes PolSARpro produce the following error when trying to read the product file.

ERROR IN THE TERRASAR-X DATA MODE and/or LEVEL

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The data is not problematic and it can be read and displayed by NEST easily. What can I do to extract T3 and C3 matrices in PolSARpro (envi) format like the following?

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Because the data are "detected", you have real amplitude values only, not complex values which also include the polarimetric phase. Without the phase information, you cannot form the covariance or coherency matrices, which is exactly what the software is telling you. It's not that the data are "bad", just that they don't contain sufficient information to process them in those matrix representations.

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As @Benjamin tells, these data do not have the capability to extract covariance or coherence matrices, My problem was solved 5 months ago and I should have ordered SSC data of TerraSAR-x.

From the TerraSAR-X Documentation and in Basic Product Specification PDF File on pages with the following specifications (issue and update):

  • Doc.: TX-GS-DD-3302
  • Issue: 1.9
  • Date: 09.10.2013

and on pages 40 and 41 we have:

Single Look Slant Range Complex (SSC)

Geometric Projection: Azimuth – Slant Range (time domain)

This product is the basic single look product of the focused radar signal. The pixels are spaced equidistant in azimuth (according to the pulse repetition interval PRI=1/PRF) and in slant range (according to the range sampling frequency) and the data are represented as complex numbers. Each image pixel is processed to zero Dopper coordinates, i.e. perpendicular to the flight track. This convention is compatible with the standard slant range products available from ERS-1/2, ENVISAT/ASAR, RADARSAT and from X-SAR/SIRC.

Spotlight products will be processed to zero Doppler coordinates like stripmap products with an artificial PRF selected large enough to hold the total processed Doppler spectrum. The products are therefore widely compatible with complex stripmap products. However, it must be considered that the Doppler centroid varies strongly with azimuth.

The SSC product is intended for scientific applications that require the full bandwidth and the phase information, e.g. SAR interferometry and interferometric polarimetry. Any possible offsets in the antenna phase pattern between TSX-1 and TDX-1 will be compensated and annotated in the product when applicable.

Multi Look Ground Range Detected (MGD)

Geometric Projection: Azimuth – Ground Range (without terrain correction).

This product is a detected multi look product with reduced speckle and approximately square resolution cells on ground. The image coordinates are oriented along flight direction and along ground range. The pixel spacing is equidistant in azimuth and in ground range. A simple polynomial slant to ground projection is performed in range using a WGS84 ellipsoid and an average, constant terrain height parameter.

The advantage of this product is that no image rotation to a map coordinate system is performed and interpolation artifacts are thus avoided. Consequently, the pixel localization accuracy is lower than in geocoded products. As for all TS-X L1b products, a coarse grid of coordinates is annotated in the product. The grid coordinates are calculated using a coarse DEM, while the projection of the image data is performed using an ellipsoid with one elevation determined for the scene.

So in MGD(Multilook Ground Detected) format, we've lost real and imaginary parts of complex data and PolSARpro can not read them and extract coherency and covariance matrices of polarimetric data and for this application, we need SSC (Single look Slant range Complex) data.

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