A radar data-based strategy for the estimation of the frequency sweep rate of airborne FMCW SAR systems.

In this work, we present a new approach for estimating the Frequency Sweep Rate (FSR) value of an airborne Frequency Modulated Continuous Wave (FMCW) Synthetic Aperture Radar (SAR) system.The proposed method is based on the use of acquired radar data and extends the recently developed the FSR Estimate Through Corner reflectors (FSRETC) algorithm, which requires the availability of one SAR acquisition and at least two Corner Reflectors (CRs) located on the illuminated scene at different range distances from the sensor. The proposed approach instead exploits only one CR and at least two non-coincident parallel SAR acquisitions. It is thus very useful in application scenarios, such as the emergency ones, where the proper deployment of different CRs on the scene to be illuminated, along with the corresponding measurement of their positions, can be difficult. The algorithm is very easy to implement and it has been tested on real airborne SAR dataset acquired at X-Band by the Italian Multiband Interferometric and Polarimetric SAR (MIPS) system. Comparison with the results achievable with the FSRETC algorithm are also provided.