Data Processing and Accuracy Verification for Laser Altimeter of Terrestrial Ecosystem Carbon Inventory Satellite

Objectives The terrestrial ecosystem carbon inventory satellite(TECIS) is the first satellite using for observation joint active and passive detectoras of forest carbon sinks in China. Multi-beam light detection and ranging (LiDAR) is the main payload of TECIS,which used to obtain high-precision vegetation height, forest biomass inversion survey and calculate characteristic information of trees such as height by calculating the time difference between reaching the canopy and the ground. It is important to achieve the integrated processing of active and passive loads and achieve accurate biomass inversion.

Methods We introduce the data processing method of multi-beam LiDAR system, and propose the joint calibration method for multi-beam LiDAR and optical cameras.What is more,we propose a verification method for the relative position relationship among multi-beam LiDAR, axis monitoring optical camera and zero degree optical camera. It is the first time for calibrating multi-beam LiDAR system and the zero degree camera in the same time and verified the relative positioning relationship between multi-beam LiDAR non imaging loads and optical cameras scientifically and rigorously.

Results (1) In plain areas, the height measurement accuracy of multi-beam LiDAR is better than 0.7 m and the plane positioning accuracy is better than 6 m. (2) By using the positioning accuracy verification method of laser data and zero degree optical camera data based on combination of field control points and back-projection points, the matching errors between beams 1 to 5 of the multi-beam LiDAR and the zero degree optical camera are 4.14 m, 4.42 m, 3.90 m, 4.27 m and 4.30 m, respectively, which can prove that it is possible that the laser data and optical camera data can be used together. (3) By using the positioning accuracy verification method of laser data and axis monitoring optical camera data based on zero degree optical camera, the matching errors between beams 1 to 5 of the multi beam LiDAR and axis monitoring optical camera is 0.72, 0.74, 0.70, 0.73 and 0.74 axis monitoring optical camera pixels, respectively. The data matching accuracy of the laser data and axis monitoring optical camera data is good.

Conclusions The experimental results show that the data processing method of TECIS and the verification method of laser data and optical camera data proposed are feasible. The target of high-precision processing and accuracy verification for the first forestry remote sensing satellite of China has come ture,which can use for monitoring of terrestrial ecosystem carbon storage, forest resources and forest productivity.It also can meet the requirements of subsequent scientific research and large-scale business applications. Meanwhile, the verification method of laser data and optical camera data can be used for accuracy verification of similar satellites in the future.