CARABAS-an UWB low frequency SAR

The significance of low-frequency ultrawideband (UWB) radar imagery has been investigated. In order to verify the theoretical predictions, an airborne SAR (synthetic aperture radar) system, operating over the frequency band 20-90 MHz, has been developed. CARABAS (coherent all radio band sensing) adopts a major part of the shortwave radio band for the transmission and reception of UWB signals. As a result, the system has a high geometric resolution, in particular in relation to the emitted wavelengths. A first data collection campaign took place in January 1992; initial data are still in the phase of evaluation. In the wavelength interval adopted, vegetation is transparent and radiation penetrates the ground to a significant degree. The system is considered capable of mapping structures and objects obscured by vegetation or buried in the ground.<>