A Multi-Frequency FMCW GBSAR: System Description and First Results

This paper provides a high level overview of a multi-frequency Ground-Based Synthetic Aperture Radar operating at X-, C-, L- and P-bands. The system core is implemented using a flexible high performance Software Defined Radio, aided by a custom radio-frequency front-end. The capabilities of the system are demonstrated by measuring dense time-series of a vegetated area. The benefits of lower frequencies appear as a significant increase in phase stability and coherences at P- and L-bands, which is explained by the increased vegetation penetration depth of these bands compared of C- and X-bands. It is concluded that multi-frequency measurements closely spaced in time are valuable and suggest new applications in vegetated areas.