The LORAM airborne radar experiment: Final report

LORAM is an airborne radar experiment performed jointly by FOI and ONERA with the objective of evaluating performance of detecting stationary and moving ground vehicles in forest concealment. FOI participated with CARABAS-II and LORA in the bands 20-86 MHz and 224-514 MHz, respectively, and ONERA participated with RAMSES in P-, L- and X-band. The main experiment (LORAM 2004) was conducted in September and October 2004, but a second experiment (LORAM 2005) was added since LORA data in 2004 showed poor signal-to-noise ratio. The LORA data from 2005, however, gave expected noise levels. The image quality achieved allowed also humans to be detected under certain circumstances and RCS measurements made are given in the report. The report focuses on analyzing LORA data collected during LORAM 2005 as well as comparing change detection performance using CARABAS-II in 2004 and LORA in 2005 over comparable ground deployments. The main conclusion from the comparison is that the overall best detection performance was obtained by CARABAS-II at the steepest incidence angle of 58°. LORA gave about two orders of magnitude (100 times) more false alarms for the same detection probability. For higher incidence angles, both CARABAS-II and LORA performance degraded but LORA gave the best detection performance at the highest incidence angle of 75°. Suggested future work for improving detection performance is also given, e.g. by increasing the aperture angle. Examples of processing CARABAS-II images to a 360° aperture angle are given in the report.