Relative Stability Analysis of Laser Pointing and Camera Imaging of Space Lidar CASAL

One of the main payloads of Terrestrial Ecosystem Carbon Inventory Satellite is the Carbon Sinks and Aerosol Lidar, which is used to measure forest and aerosol profiles. The lidar is made up of a five-beam laser altimeter and an aerosol lidar, as well as a near nadir-pointing camera, which is used to obtain high-resolution multi-spectral images of the forest. The relative stability of laser pointing and camera imaging is essential for reconstructing 3D structures of the forest, and further calculating above ground biomass. In this paper, the overall principles to meet mission requirements and ensure high stability of laser pointing and high-resolution camera imaging is introduced, and design scheme of the laser altimeter and high-resolution camera are presented, and in-depth stability analysis is made from both structural and timing aspects. Ground verification results are listed, and show good stability. This work provides an important basis for calculating the vegetation biomass by use of horizontal distribution and vertical profile information of vegetation, especially forest, on orbit.