IMU／DGPS系统辅助ADS40三线阵影像的区域网平差

IMU/DGPS Supported Block Adjustment of ADS40 Three Line Imagery Data

推导ADS40航带间外方位元素归一化处理的数学公式,设计一种描述IMU/DGPS系统误差的数学模型,采用改进的定向片内插模型实现ADS40影像的区域网平差。试验结果表明,仅需一个地面控制点,IMU/DGPS数据的定位精度就可显著提高,在四角布设地面控制点的情况下,IMU/DGPS数据与ADS40影像的联合平差可得到优于1.5个像素的3维定位精度;构架航线对平差结果的改善作用有限,在作业中采用的必要性不大。

This paper makes a comprehensive study on the triangulation of ADS40 airborne three line images supported byGPS/IMU data. Considering that different Local Space Rectangular （LSR） systems have been adopted for different ADS40 strips, the equations to transform the exterior orientation elements of all ADS40 strips to one LSR frame are derived at first, then the principle of the block adjustment of three-line image using orientation image is introduced and a math model to describe the error of IMU/DGPS data is designed. Two datasets from Waldkirch test field located in Switzerland, which have been acquired in May 2002 with the GSD of 20 cm and September 2004 with the GSD of 35 cm respectively, are used to test the correctness of algorithms mentioned above. Block adjustment experiments have been carried out for the blocks constructed by all west-east strips and plus two cross strips at each end of them. Results indicate that the positioning accuracy of IMU/DGPS data can be promoted effectively when only one ground control point is introduced into adjustment. While locating one control point at each corner of the block, the combined adjustment of IMU/DGPS data with ADS40 image observations achieves the accuracy of 1. 5 pixels on the ground. The cross strips are not good for combined adjustment and not recommended in actual application.