Elevation Variation Effects Comparison between LEO and GEO SAR

Geosynchronous (GEO) orbit and low-earth-orbit (LEO) in imaging have many differences, especially for relief of undulating three-dimensional(3D) terrain, the imaging errors caused by target elevation in two orbits of different altitudes are also diverse. The error caused by terrain elevation under the LEO SAR is negligible, and in GEO SAR the error will cause serious azimuth defocusing. This paper focuses on the error caused by topography elevation in LEO and GEO SAR respectively. Firstly, the SAR imaging geometric model including terrain elevation is established. Then, the source of error caused by terrain elevation and its influencing factors are analyzed. Finally, the error changes of the two orbits are analyzed, and the correctness of the proposed viewpoint is verified by experiments.