Studiu al configuratilor SAR multistatic / A study on multistatic SAR configurations

Multistatic SAR is an emerging technology with benefits hitherto unmatched by other remote sensing methods, providing “best-in-stock” sensing solutions that are weather and day-time independent, such as real-time along and cross track interferometry for Digital Elevation Modeling, enhanced ocean analysis, and improved resolution, to name a few. Existing missions such as TanDem-X have already provided an example of the possibilities offered by multistatic SAR, however, the small baseline of just a few km limits overall performance and multistatic capabiliteis. A future mission with larger baselines (>200km), called Harmony, is intended to premiere as the first true fully spaceborne multistatic SAR. Harmony satellites will be equipped with passive SAR receivers and use the existing Sentinel satellites as an opportunistic transmitter. The experiments and developments presented within this thesis are made using a bistatic SAR system using Sentinel 1 as an opportunistic transmitter and the COBIS as a ground-based receiver. The main subjects are multiaperture focusing for improved cross-range resolution, and near-range multipath mitigation techniques to resolve undesired sync-to-imaging channel coupling/multipath or TX-RX feedback in transponders. Furthermore, a VCO architecture for low-power and reduced size FMCW multistatic SAR systems with high range resolution is presented along with a novel near-field phased array calibration method. Future work will be to adapt the methods developed within this thesis to be compatible with fully spaceborne and airborne multistatic SAR systems.