The Calibration And Application Of Boresight Misalignment In Airborne LiDAR Measurement System

Airborne LiDAR measurement system is an emerging space earth observation technology.It has many advantages such as speediness, non-contact, penetrating, initiative, high-density, high-precision and high efficiency. It has made a major breakthrough in spatial information real-time acquisition.It has been researched widely at home and abroad and has been used by many departments.The point cloud data got by airborne LiDAR measurement can directly shows the surface features’ three-dimensional information. It has a high height precision. Aerial image can reflect the spectroradiometer features’ characteristics accurately. It has a high plane precision. The fusion of point cloud and aerial image can combine the advantages of these two data sources. It can not only improve the accuracy, but also provide more accurate raw data for further surface feature’s classification and extraction.The small deviation of the corresponding axis between IMU coordinate system and aerial instrument coordinate system is called the boresight misalignment. It mainly affects the accuracy of the orientation parameters. The real physical state of the image exposure and any deviations of the assumed mathematical model can lead to major mistakes of object’s spatial location.So the boresight misalignment can affect the point cloud and aerial image’s registration.Therefore, studying the rapid calibration of boresight misalignment has an important practical significance.On the base of detailed analysis of the source of airborne LIDAR measurement system errors and their effects on laser points’ coordinates, this paper makes a thorough study on the solution of boresight misalignment.The main research contents of this paper include:①The acquisition of initial data(point cloud、aerial images’ exterior orientation elements、DEM etc.)、multi-baseline photogrammetry(to solve connection points’ ground coordinates)、interpolation of DEM(to get high-precision elevation values)、calculation of the least square model of boresight misalignment(to solve the boresight misalignment with obtained data and least squares model).②The implementation of object-oriented programming by C#:mainly includes interface design、structural design of class module、matrix algorithms and interpolation algorithms of DEM. According to the mathematical model, it can achieve the boresight misalignment by using C#.③The evaluation of accuracy of calculation result, and the application in actual production of laser data.Finally, by using C#, the paper realizes the rapid calibration of boresight misalignment without any control fields. Compared with no calibration, the result can be used to correct image’s exterior orientation elements and manufacture DOM with higher accuracy.It can improve efficiency and reduce production costs.