CBERS-02B卫星遥感影像的区域网平差

针对中巴资源一号卫星(CBERS-02B)卫星遥感影像姿态角误差较大的特点,提出了利用区域网平差方法提高其对地目标定位精度的策略和具体计算过程。首先对参与平差的每景影像选取4个地面控制点进行影像姿态角常差检校,然后采用与地形无关方案解求各自的RPC参数,最后选取带仿射变换项的有理函数模型(RFM)进行多重覆盖影像的区域网平差。对两个地区的0级CBERS-02B单条CCD立体影像对的区域网平差试验表明,对地目标定位的平面和高程精度均达到了±3个像元的水平,且高程精度明显优于平面精度。相对于常规的卫星遥感影像区域网平差方法,平面和高程精度均有明显提升,几乎达到国外同等高分辨率卫星遥感影像的几何定位精度。这说明中国卫星遥感影像亦具有较好的几何定位潜力,在区域网平差之前进行系统误差预改正是必要和可行的。

Block adjustment for CBERS-02B satellite images

In order to analyze the characteristic of large attitude angle errors of CBERS-02B satellite imagery, this paper proposesa specific strategy and algorithm to improve the point determination accuracy by using block adjustment. First, the errorsof attitude angles are calibrated according to four Ground Control Points (GCPs) around the four corners of each image. Then theRational Polynomial Coefficients (RPCs) of each imagery are solved using terrain-independent approach. The Rational FunctionModel (RFM) with the affine transformation parameters is applied for the bundle block adjustment of CBERS-02B satellite images.Two CBERS-02B stereo pairs in level 0 acquired by a single CCD are selected in our test. The experimental results haveshown that an accuracy of ±3 pixels can be attained both in plane and elevation. Moreover, the elevation accuracy is better thanthe planimetric accuracy. Comparing to the bundle block adjustment without pre-correction, the method proposed in this papercan improve the accuracy both in plane and elevation to a similar accuracy level of foreign High-resolution Satellite Images(HRSIs), which indicates that Chinese satellite images have good potential for geometric positioning. These experiments furthershow, the pre-correction before bundle block adjustment is necessary and feasible for the images in geometric processing.