Research on the Composite Surveying Accuracy of Laser Altimetry Data and Stereo Images From the Terrestrial Ecosystem Carbon Monitoring Satellite

ABSTRACT Terrestrial ecosystem carbon monitoring satellite (CM‐1) equipped with multi‐beam LiDAR, multi‐angle multi‐spectral camera and other payloads, which can carry out high accuracy stereo mapping applications, has become a new member of China's civilian stereo mapping satellite series following GF‐7 and ZY‐3. Aiming at the composite mapping capability for the satellite, this paper studies the extraction of laser elevation control points and the composite surveying method combined with stereo images, and compares and analyzes the accuracy of composite surveying from three perspectives: different terrains (include flatland, hilly terrain, mountainous region, and alpine land), different angles of optical stereo images (38° and 82°), and different satellites (CM‐1, ZY3‐03, and GF‐7). The experimental results show that the elevation accuracy of the laser points after screening and extraction is decreased from 2.41 and 4.13 m to 0.44 and 0.607 m, respectively, which can be used as elevation control points for stereo mapping. The accuracy of composite surveying can be improved from 11.45 to 2.27 m, and different terrain conditions are significantly improved. Stereo images of different angles can be combined with laser for mapping, but the accuracy of the image of 38° convergence angle is better than 82°, and spatial resolution may be the main influencing factor. Among different Chinese satellites, the relative elevation accuracy of DSM generated by GF‐7 satellite is better than that of the other two satellites, and the elevation accuracy of DSM generated by CM‐1 satellite is equivalent to that of ZY3‐03 satellite. The relevant conclusions have reference value for giving full play to the application advantages of laser elevation control points and serving the production of real‐scene three‐dimensional terrain‐level products in China.