Iterative Pointing Angle Calibration Method for the Spaceborne Photon-Counting Laser Altimeter Based on Small-Range Terrain Matching

Abstract

The satellite, Ice, Cloud and Land Elevation Satellite-2 (ICESat-2) has been equipped with a new type of spaceborne laser altimeter, which has the benefits of having small footprints and a high repetition rate, and it can produce dense footprints on the ground. Focusing on the pointing angle calibration of this new spaceborne laser altimeter, this paper proposes a fast pointing angle calibration method using only a small range of terrain surveyed by airborne lidar. Based on the matching criterion of least elevation difference, an iterative pointing angle calibration method was proposed. In the experiment, the simulated photon-counting laser altimeter data and the Ice, Cloud and Land Elevation Satellite-2 data were used to verify the algorithm. The results show that when 1 km and 2.5 km lengths of track were used, the pointing angle error after calibration could be reduced to about 0.3 arc-seconds and less than 0.1 arc-seconds, respectively. Meanwhile, compared with the traditional pyramid search method, the proposed iterative pointing angle calibration method does not require well-designed parameters, which are important in the pyramid search method to balance calculation time and calibration result, and the iterative pointing angle calibration method could significantly reduce the calibration time to only about one-fifth of that of the pyramid search method.

Spaceborne LiDAR Surveying and Mapping

“…The main steps include two steps: firstly, terrain matching is used to obtain the common terrain feature points whose coordinate deviations are used as input observations, and the second step is to calculate the system calibration parameters by laser beam adjustment. As shown in Figure 10, the specific solution can be simplified to calibrate two pointing angular parameters (θ 0 , β 0 ) and 1 range parameter r. It has been shown that the angular calibration accuracy is better than 0.3 arc second using 1 km length laser line matched with high-precision terrain, and the angular calibration accuracy is better than 0.1 arc second when the line length is increased to 2.5 km [52]. In addition, ICESat-2 adopts a similar strategy to ICESat for attitude maneuvering in the oceanic region, and the attitude and distance are calibrated separately by conical scanning, and the long-term drift of the calibrated range values is less than 1 mm/year [53].…”

Research on angle calibration method of space station indexing mechanism based on artificial intelligence

“…It is easy for later calibration processing. [4] Select the rotation speed and rotation direction, control the lower test bench motor to rotate continuously at the selected speed. After a week of rotation, end the experiment.…”

Forest Terrain Inversion Based on Icesat-2/ATLAS with Different Laser Intensities

“…To evaluate the relationship between the inverse forest floor and airborne G-LiHT data at different laser intensities in the ATLAS data, the coefficient of determination (R 2 ), root mean square error (RMSE), and absolute mean error (MAE) at two laser intensities were separately statistically evaluated [11,[27][28][29]. To investigate the extent to which the vegetation canopy height and vegetation cover at different ATLAS laser intensities affected the accuracy of DTM inversions in the forest understory, we separately conducted inversions for different laser types within different canopy scales (zone groups), using the ATLAS ground photon elevations minus the corresponding elevations of airborne G-LiHT, and statistical indicators of errors by laser type (RMSE, R 2 , MAE number, and weight of different canopy heights (N)) [30,31].…”