Large-footprint Laser Scanner With High-speed Echo Digitization For Informatioan Extraction And Verification

Space-borne laser altimeter system can be used to detect vertical distribution of surface features, it is an important means and development trend to acquire terrain feature information and realize the elevation surveying by processing its waveform data. In this paper, the research on full-waveform decomposition algorithm and related technologies of ground verification system of large-footprint lidar were carried out, to provide an important reference for system design and waveform data processing algorithm study of space-borne earth observation laser altimeter system.The paper first introduces the domestic and alien developments of space-borne laser altimeter system and waveform data of large-footprint lidar, and then carries out the research on full waveform decomposition algorithm and related technologies of ground verification system of large-footprint lidar. Based on the related principle of Gaussian model and waveform processing algorithm, an echo model is introduced to conduct modeling and simulation analysis on echo with typical features. To obtain the echo data, a ground verification system of large-footprint lidar is designed and built, the research and functional verification on key technologies such as constant fraction discriminator, detecting circuit of echo signal, high-speed full waveform data acquisition circuit, TDC time measurement which is based on FPGA were carried out. Finally, in order to extract the relative distance information of multi-objects from the echo waveform of space-borne earth observing laser altimeter with large-footprint, a Levenberg-Marquardt-based Gaussian decomposition algori--thm was used to separate the waveforms, experiments on the ground-based multi-objective distance information acquisition were carried out to verify the decomposition algorithm and ground verification system of large-footprint lidar. The calculated relative distance error of multi-objectives was less than 0.03 m which revealed the effectiveness of algorithm in separating multi-objects from echo waveforms and the validity of ground verification system of large-footprint lidar, which provides the theory and design basis for the subsequent target recognition and classification research and flight test plan.