缺少控制点的星载SAR遥感影像对地目标定位

Object Location of Space-borne SAR Imagery Under Lacking Ground Control Points

从距离和多普勒方程出发,构建了无需地面控制点的直接对地目标定位模型,推导了缺少控制点时的精化轨道参数及成像几何参数等的数学模型。经过对北京某地区一景ENVISAT ASAR影像进行直接对地目标定位,获得了实地上±170.966 m(约±8.7像素)的平面精度;利用单个地面控制点对星载SAR影像的定向参数实施调整后,对地目标定位平面精度提高到±54.665 m(约±2.8像素),控制点数目增加到4个时,对地目标定位平面精度接近±2像素。结果显示,对困难地区采用星载SAR遥感影像对地目标定位具有很好的应用前景。

The slant-range imaging principle of space-borne SAR sensor is discussed, and from the Range Doppler equations, the direct georeferencing model without ground control points （GCPs） is formulated. In the conditions of the lack of GCPs, the model for adjusting the model parameters, including the track model parameters and image geometric processing parameters, is derived in detail. Direct georeferencing is made on a scene of ENVISAT ASAR imagery of Beijing area, and planimetric accuracy of 170. 966 m（±8.7 pixels） is obtained. After using one GCP to adjust some model parameters, the planimetric accuracy is improved by ±54. 665 m（±2.8 pixels）. The experiment shows that in the condition of the lack of GCPs the positioning accuracy for space-borne SAR imagery can approximate to two ground sampled distance, and will has a good application prospects, especially for the georeferencing of the difficult areas.