摘要
垂轨环扫传感器能兼顾实现超大幅宽(千公里级)与高分辨率(米级)成像,其影像数据量远超传统卫星(单景影像达几百GB)。为了探究该成像方式下影像有理函数模型的适用性和精度,基于垂轨环扫传感器成像原理构建其严格成像模型。针对垂轨环扫影像特性,提出一种结合数字高程模型的地形相关控制点布设方案。采用星下点坐标确定初始迭代区间的方法解决大幅宽条件下反投影计算失效的问题,从而实现任意幅宽影像整景范围内物方坐标到像方坐标的求解。最后,通过生成不同幅宽的模拟影像及姿轨数据完成有理函数模型的建立,探究有理函数模型对严格成型模型的拟合精度。实验表明:3000 km幅宽时,一景实验影像在大地坐标系下地形无关、地形相关方案得到的有理函数模型的拟合误差分别为3004.25,1939.04 pixel;地心直角坐标系下的拟合误差为27.50,24.96 pixel。影像大幅宽时,主要受地球曲率影响,大地坐标系解算的RPC误差极大;在地心直角坐标系下解算的RPC具有更高的拟合精度,但二者均无法实现对严格成像模型的高精度拟合。对垂轨环扫卫星影像有理函数模型拟合精度的初步探究为卫星入轨交付后的影像处理奠定了技术基础。
The perpendicular-orbit circular scanning sensor,a new optical imaging system,can capture images with an ultra-wide swath width(thousand-kilometer level)and high resolution(meter level)that are much larger than those obtained by traditional satellites(with a single image being up to several hundred gigabytes).A rigorous imaging model was constructed for the perpendicular-orbit circular scanning sensor based on an analysis of its imaging principles.Based on the characteristics of the perpendicular-orbit circular scanning sensor,a terrain-dependent control point layout scheme combined with DEM was developed.In addition,a method to determine the initial iteration interval was proposed using the coordinate of the sub-satellite point to solve the problem of back projection calculation failure under the condition of a wide swath,which could help obtain a solution from the object space coordinate to the image space coordinate within the whole scene range of an arbitrary-width image.In this study,a RFM construction test was conducted by simulating images with different swath width,orbital,and altitudinal data to explore the fitting accuracy of RFM in different object square coordinate systems.When the swath width of the image reaches 3000 km,the RFM fit error is 3004.25 and 1939.04 pixels in different schemes.The RFM fit error constructed by the terrain-dependent scheme is 27.5 and 24.96 pixels when a geocentric rectangular coordinate system was used.Images captured by the perpendicular-orbit circular scanning sensor can have widths of several thousand kilometers;therefore,the accuracy of RPC is significantly affected by the curvature of earth,and the accuracy of RPC solved under the condition of geocentric rectangular coordinate system is better than that of a geodetic coordinate system.The initial exploration of the RFM accuracy of perpendicular-orbit circular scanning sensor images can provide a foundation for the application of the satellite.
作者
刘宪
薛武
王鹏
LIU Xian;XUE Wu;WANG Peng(Space Engineering University,Beijing 101416,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2023年第19期2898-2909,共12页
Optics and Precision Engineering
基金
航天工程大学青年创新基金资助项目。
关键词
垂轨环扫
严格成像模型
有理函数模型
反投影计算
精度评估
perpendicular-orbit circular scanning sensor
rigorous sensor model
rational function model
back project calculation
accuracy assessment
