Bistatic P-band SAR signatures of forests and vehicles

We present results from the LORAMbis bistatic VHF/UHF-band SAR experiment conducted in September 2010. The SAR flights were performed with the French SETHI system and the Swedish LORA system installed in two aircraft. Frequency band was 222-460 MHz and polarization was HH. Results from two tests sites (Kvarn and Remningstorp, both in southern Sweden) show that forest clutter generally decreases for increasing bistatic elevation angles. This observation is explained by reduction of the ground-trunk double-bounce scattering mechanism. Results also indicate that vehicles in forest concealment are often better discriminated in bistatic compared to monostatic SAR images. Examples of signal-to-clutter-ratio measurements for vehicles show an increase 7-17 dB when the bistatic elevation angles increased from 0° (quasi-monostatic) up to 10°. These show the potential for improved target detection using VHF/UHF-band bistatic SAR.