Analysis and on-orbit verification of aiming accuracy for spaceborne SAR

With the resolution of spaceborne synthetic aperture radar reaching sub meter level, the mapping bandwidth is only 3km to 5 km. This reduces the effectiveness of aiming and capturing the observed target. Therefore, it is necessary to analyze the influencing factors for aiming accuracy of spaceborne SAR. This article conducts analysis from the aspects of ground telemetry/track and command system, ground operation control system, satellite platform and payload. An error model based on the influencing factors of entire satellite-ground link and on-orbit testing method suitable for any scenario are proposed. The results of theoretical prediction and real test show that 120m orbit height prediction error, 90m target elevation error, 5m slant measurement error, 0.03° satellite attitude pointing error and 0.01° systematic beam pointing error of SAR antenna will bring about 400m aiming accuracy.