Research on High-precision Ground Measurement Technology of Solar Radiation Pressure on the Surface Materials of GEO-SAR Satellites

Geosynchronous synthetic aperture radar （GEO-SAR） satellite is a type of microwave imaging satellite, which operates in the Geosynchronous Orbit with an altitude of 36,000 km. Its orbit determination accuracy and orbit prediction accuracy are important factors affecting the imaging positioning accuracy and image quality. Due to the orbital height characteristics of the geostationary orbit, the solar pressure received by the satellite in orbit is the largest force among non-conservative perturbation forces received by the satellite, which will significantly affect the orbit determination accuracy and orbit prediction accuracy of the satellite, and then affect the imaging positioning accuracy and imaging quality of the satellite. Measurement of solar pressure response characteristics of spacecraft surface materials is helpful to accurately model the optical pressure of GEO-SAR satellite in orbit and improve the accuracy of satellite orbit determination. The solar pressure response of the spacecraft surface is related to the material, process, surface state and so on. Ground-based laboratory measurement results can effectively validate and refine the modeling parameters and improve the accuracy of orbit determination. In this paper, a special measurement system for optical pressure of GEO-SAR satellite surface material on the ground is developed, which has the characteristics of high sensitivity, high precision, wide range, resistance to interference and vibration. The test piece is measured in the vacuum environment chamber. The system is composed of five parts: micro force measurement system, vertical pendulum and its steering system, vibration suppression system, force calibration system, data acquisition and processing system. It breaks through the key technologies such as gravity decoupling, secondary vibration reduction, optical chopper modulation, and realizes the measurement of micro force signal and simulated optical pressure of spacecraft surface materials in disturbed environment. The designed system can meet the requirements of high-precision measurement of optical pressure of GEO-SAR satellite surface materials on the ground.