No abstract

Spaceborne interferometric synthetic aperture radar (InSAR) technology is an effective method to obtain digital elevation model (DEM) data. The bistatic InSAR configuration of the inclined-geosynchronous (InGEO) transmitter with low earth orbit (LEO) receivers (InGEO-LEO) is a novel InSAR system to acquire terrain information. This novel system is characterised with high resolution, wide swath and timeliness, but the Newton iterative method is time-consuming to solve the bistatic InSAR equations for fast DEM generation. For the conventional LEO bistatic InSAR system, the closed-form solution is an effective method to improve the efficiency of solving InSAR equations, which is invalid in the InGEO-LEO InSAR system because of the significant geometry difference caused by the orbits of InGEO transmitter and LEO receivers. To address this issue, we analyse the bistatic InGEO-LEO geometry in detail and exploit the bistatic InSAR equations to propose an approximate closed-form solution (ACS) for the novel system. Compared with the general Newton iterative method, the ACS significantly improves the efficiency of geolocation for the bistatic InGEO-LEO InSAR system with high precision. Simulation experiments are carried out to verify the effectiveness and superiority of ACS.