CAJ | 학술논문

低空机载平台的运动存在剧烈的扰动和不确定性,使得通过其进行SAR成像的难度增大,本文提出了将快速后向投影(FFBP)算法和RTK系统高精度定位信息结合进行运动补偿,从而可以快速地获得高质量的SAR图像的方法.由于定义测绘区和成像过程中的子图像划分采用不同的坐标系,使得成像时需要对感兴趣区域进行锁定,本文提出成像区域锁定算法,能够进一步提高计算效率.最后将RTK系统的空间位置信息引入FFBP算法时本文分析了两种思路,一种是将航迹拟合为直线,将各个子图像的原点补偿至一条直线上,另一种思路是将子图像的原点补偿至一条曲线上,后者具有更高的补偿精度和适应性,但是同样也带来更高的复杂度,影响计算效率.通过两组实测数据的比较,本文认为在机载平台航线能够拟合为一条直线的情况下,应该采用近似补偿的方法以获得较高的计算效率.
저공궤재평태적운동존재극렬적우동화불학정성,사득통과기진행SAR성상적난도증대,본문제출료장쾌속후향투영(FFBP)산법화RTK계통고정도정위신식결합진행운동보상,종이가이쾌속지획득고질량적SAR도상적방법.유우정의측회구화성상과정중적자도상화분채용불동적좌표계,사득성상시수요대감흥취구역진행쇄정,본문제출성상구역쇄정산법,능구진일보제고계산효솔.최후장RTK계통적공간위치신식인입FFBP산법시본문분석료량충사로,일충시장항적의합위직선,장각개자도상적원점보상지일조직선상,령일충사로시장자도상적원점보상지일조곡선상,후자구유경고적보상정도화괄응성,단시동양야대래경고적복잡도,영향계산효솔.통과량조실측수거적비교,본문인위재궤재평태항선능구의합위일조직선적정황하,응해채용근사보상적방법이획득교고적계산효솔.
Terrible disorder and serious uncertainty of the low-altitude airborne system's motion increase the difficulty of SAR (Synthetic Aperture Radar) imaging. This paper presents a motion compensation method that brings the RTK data of high precise position information into FFBP (Fast Factorized Back Projection) algorithm to get a high quality SAR image. The coordinates of the defined target area are different from the sub-image's coordinates, how to aim at the interested area under the polar coordinates is presented in order to increase the computation efficiency. There are two methods to introduce the position information into FFBP to compensate motion error. One method is to approximate the track to a line, and the origins of the sub-images are set on it. Another method set al.l the origins on the trace curve that bring in higher compensation precision and also higher complexity. Finally two practical results are presented to prove the algorithm's availability, and also suggest the approximate compensation method (the former one) for efficiency reason when the asymptote of the aircraft's trace is linear.