Fast Geolocation Solution and Accuracy Analysis for Bistatic InSAR Configuration of Geostationary Transmitter with LEO Receivers

To obtain digital elevation model (DEM) data through spaceborne interferometric synthetic aperture radar (InSAR) technology, the solution of nonlinear InSAR geolocation equations is one of the most important steps. On one hand, Newton iterative method is time-consuming to solve the equations. On the other hand, the conventional closed-form solution for low earth orbit (LEO) bistatic InSAR system is not suitable for the novel InSAR configuration of geostationary (GEO) transmitter with LEO receivers because of the significant geometry difference. To address these issues, this letter analyzes the bistatic GEO-LEO geometry in detail and exploits the bistatic InSAR equations to propose a GEO-LEO fast location method (GFLM), which obtains the effective closed-form solution for the novel system. Compared with the general Newton iterative method, the GFLM significantly improves the efficiency of geolocation for the bistatic GEO-LEO InSAR system with high precision. Moreover, the geolocation accuracy of the novel system under realistic parameters uncertainties is introduced. Finally, we carry out simulation experiments to verify the effectiveness and superiority of GFLM.