Sisir Radar analyses L band SAR polarimetric response across incidence angles for space missions

For selecting optimum operating conditions for our planned spaceborne L and P band SAR constellation, we are conducting repeated flights over similar terrains. We are investigating Polarimetric performance over incidence angle variation. Our drone SAR data in L band was processed from nadir to 75 deg incidence angle. An example image in L band, auto-registered with Google Earth, is presented for better understanding. Kindly note that the left side of the image is closure to the flight track.

Our preliminary observations on L band Polarimetric signatures can be summarised as:

Very strong foliage penetration occurs up to around ~30 deg incidence angle.

From 0 to ~15 deg, radar backscatter is dominated mainly by surface returns (blue tone).

Upto ~30 deg incidence angle, radar backscatter has significant surface and vertical structure returns (blue and red tones).

Beyond ~30 deg to almost ~70 deg, Polarimetric backscatter returns exhibit very good admixture of returns from surface, vertical and foliage signatures.

At higher incidence angles, the SAR signal has longer interaction with foliage, increasing the foliage signatures (green tone) with incidence angle. With higher and higher incidence angles, the foliage signatures become more and more prominent.

#sisirradar #SAR #Lband #Pband