2016(1):22-27.
Abstract:
There are two main geolocation models for synthetic aperture radar (SAR): slant-to-ground range model and range Doppler (RD) model. The slant-to-ground rang model is easily calculated, but the earth curvature is ignored. And in RD model, not only the imaging principle is considered, but also the earth curvature variation is included. In this paper, the simulation experiment is implemented to show that the slant-to-ground range model has low accuracy of geolocation in the near space condition. Compared with the slant-to-ground range model, RD model has overwhelming superiority in this situation. Thus it is concluded that the earth curvature variation must be considered for near space SAR geolocation. Furthermore, the geolocation accuracy of the RD model is analyzed. The geolocation uncertainty formulas are derived, and the simulation experiment results are obtained based on the derived formulas.