Design And Testing Of Ground Footprint Detector Of GF-7 Satellite Laser Altimeter

The core data product of the spaceborne laser altimeter is the three-dimensional coordinates of the ground laser footprint in the specified coordinate system.Generally,the basic measurement data of the spaceborne laser altimeter is refined,including on-orbit calibration and data processing Remove random errors and systematic errors in the original data,and through the authenticity verification test,the accuracy of the corrected laser footprint center position is evaluated to ensure the reliability of the core data products.The footprint detection method is a commonly used method for authenticity verification.The footprint detector is the core device of the footprint detection method.The performance of the detector will directly affect the positioning accuracy of the footprint center.In order to complete the verification of the authenticity of the GF-7 satellite laser altimeter,it is necessary to design a detector with excellent performance according to the technical parameters of the GF-7 satellite laser altimeter.And it is also necessary to design a device that can quickly and accurately detect the quality of the detector based on the function and performance indicators of the detector to provide a basis for testing and evaluating the performance and quality of the detector.At the same time,it is necessary to combine the working characteristics of the detector and the networking method to study a new laser footprint center positioning algorithm,taking into account not only the original energy distribution of the space laser,but also the influence of the random disturbance of the laser in the atmospheric transmission,to ensure The higher positioning accuracy and better anti-interference ability realize the positioning of the footprint center.1.Taking the technical parameters of the GF-7 satellite laser altimeter as input,the function and performance requirements of the detector are proposed,and the function of the detector is designed and implemented.Furthermore,a laser foot print center positioning method based on the Levenberg-Marquard(LM)algorithm is proposed.The average error of the laser foot print center positioning is 0.1529 layout intervals.Under the condition of 4 meters spacing,the foot print center positioning error is 0.61 meters.Using this result as input,the conditions that the main performance of the detector should meet are discussed.2.According to the performance parameter requirements of the GF-7 laser detector,the overall design scheme of the detector detection and calibration platform is proposed,the design and development of the laser calibration module,energy adjustment module,beam shaping module,energy monitoring module,data processing module and auxiliary function module of the detection and calibration platform are completed,and the reliability of the detector detection and calibration platform was evaluated.3.Using the self-developed detector detection and calibration platform,the 2,500 footprint detectors to be delivered were tested.The test results show that 98.5% of the detectors have good performance,good endurance and high and low temperature resistance,and can meet the task requirements of the authenticity test of the GF-7laser altimeter.