Design of a High Precision Spaceborne Millimeter Wave SAR Corner Reflector

Ground resolution, PSLR, ISLR, system sensitivity and radiation resolution of SAR system need to be calibrated by ground calibration equipment, and the commonly used equipment is corner reflector. The structural accuracy of existing corner reflectors is generally low, which can only be applied to low frequency SAR systems. The structural error has a great impact on RCS in millimeter wave high frequency SAR systems. However, the RCS stability requirements of millimeter wave SAR corner reflectors are high, so higher precision and more stable corner reflectors are needed, and the existing corner reflectors cannot meet the requirements. Based on the calibration requirements of millimeter wave SAR, this paper analyzes and decomposes the errors that affect the RCS of the corner reflector, and determines the shape error accuracy, weight and size indicators of the corner reflector; Based on this, the structure of the corner reflector is designed, and the machining accuracy and assembly accuracy of each component are clarified through error chain analysis; At the same time, considering the influence of thermal deformation on the accuracy of the corner reflector, the thermal deformation of the corner reflector is simulated and analyzed; The integrated precision machining method is adopted for processing, and the advanced assembly process of rough machining preassembly integrated precision machining assembly correction is adopted for assembly. The profile accuracy meets the design requirements; Finally, the RCS of the corner reflector is measured by microwave anechoic chamber, and the measurement results meet the requirements. The high-precision corner reflector meets the calibration requirements of spaceborne millimeter wave SAR.