【作者】 岳昔娟；

【导师】 黄国满；

【作者基本信息】 武汉大学 ， 大地测量学与测量工程， 2009， 博士

【摘要】 合成孔径雷达(Synthetic Aperture Radar, SAR)具有全天时、全天候、穿透性等特点,已成为当前测绘困难地区数据获取和测图的重要手段。机载SAR系统具有实时获取与处理、机动灵活等特点,可依据用户需求获取大比例尺、高分辨率、高精度SAR数据,因此越来越得到各国研究者的关注,机载SAR影像精确定位随之成为SAR数据处理技术的研究重点和热点。传统的机载SAR影像定位方法需采用大量控制点,距离大面积、稀少控制区域地形测绘的应用需求还有较大差距,亟待解决稀少(无)地面控制条件下的机载SAR测图问题。本文从分析SAR影像几何特点入手,重点研究机载SAR误差源及其影响、稀少控制条件下机载SAR区域网平差、无控制条件下的机载SAR影像主动定位模型,实现复杂地形、大面积、稀少(无)控制点条件下的机载SAR影像高精度定位,提高困难地区测图精度和效率。本文的主要研究内容和主要贡献：1.分析了机载SAR定位模型。从SAR影像的几何特点和几何变形因素出发,分析了SAR影像与光学影像几何特性差异及机、星载SAR的区别；研究了机载SAR定位的原理及流程,并对机载SAR影像的定位模型及各定位模型的适用情况和优缺点进行了分析、比较。2.设计了机载多波段多极化干涉SAR测图系统关键技术指标。研究了影响干涉测量精度的因素及其引起的误差,并对机载多波段多极化干涉SAR测图系统X波段干涉SAR传感器的基线长度进行了设计,为飞机改装提供了关键技术指标。3.研究了复杂地形条件下的机载SAR航线设计方案。重点分析了SAR影像产生阴影的原因及影响阴影大小的因素,研究了机载SAR影像去除阴影的方案：加大重叠度、双向成像、垂直方向成像,定量分析了各种方法去除阴影的效果,并对横断山脉地区各种地形引起的阴影及可采用的消除方法进行了分析,对此地区进行了机载SAR航线设计。4.提出了稀少控制条件下机载SAR区域网平差模型。该模型采用了基于投影差改正的多项式法和基于F.Leberl构像模型的多片联合平差算法,可适用于不同侧视方向、不同航高、不同分辨率的多景SAR影像。根据多片联合平差模型,设计了相应的软件,进行了试验和方法改进,验证了该方法可用于平地、丘陵地区1：1万测图的区域网平差。5.提出了无控制条件下的机载SAR影像主动定位模型。研究了定位定向系统(Position and Orientation System, POS)数据处理的方法,包括天线动态偏心改正和雷达相位中心插值；提出了在无控制点情况下基于POS高精度位置和姿态数据的机载SAR高精度定位方法。试验验证了在无控制点情况下,此模型可用于1：5万测图。6.提出了稀少控制条件下机载SAR多航带区域网联合地理编码模型。研究了机载SAR多航带区域网联合地理编码算法,包括航带粗定位、机载SAR多航带区域网平差和航带精定位,并提出了机载SAR多航带区域网控制点布设方案。更多还原

【Abstract】 Synthetic Aperture Radar (SAR) Technology, characterized by its all-time, all-weather and penetrable capability, has been a primary technical means in data acquisition and mapping within the difficulty area at present. Airborne SAR system owns couple of features such as real-time acquisition, real-time processing, and flexibility; it can produce large-scale, high-resolution, and high-accuracy SAR data on the demand of users. Now it has been paid more and more attention by researchers all over the world. Therefore research on precise geolocation of airborne SAR images has been an important field in SAR data processing technologies.The traditional way of airborne SAR image positioning is employing Ground Control Points (GCPs) as many as possible, and topographic mapping in large area with few GCPs still has heavy disparity, meanwhile airborne SAR mapping with few or none GCPs is a burning question. According to the analyse on geometric characters of airborne SAR images, the main research topics of this dissertation are airborne SAR error sources and their effects, block adjustment of airborne SAR under the circumstance of few GCPs, direct positioning model of airborne SAR images with none GCP, high accuracy of SAR image positioning in extremely conditions like complex topography, large-scale, and few or no GCPs, raise in mapping effective and accuracy in difficulty area.The main research contents and contributions are as follows:1. Airborne SAR positioning models are analyzed. According to geometric characteristics and distortions of SAR images, the difference between SAR and optical images, the variances between airborne and spaceborne SAR are analyzed respectively. The principles and processing flows of airborne SAR positioning are studied. Airborne SAR positioning models are described emphatically. The availability, merits and demerits of every SAR positioning model are analyzed and compared.2. The key technical indexes of Airborne Multi-band Multi-polarization SAR Interferometry (InSAR) Mapping System are designed. Factors that restricted the accuracy of interferometry are studied and errors propagation by them is reasoned, the baseline length of X-band InSAR System is designed, which provides aircraft modification with technical foundation.3. Airborne SAR airline solution for complex terrain is studied. Reasons and factors of the shadow are analyzed spe cifically. Methods of eliminating shadow are proposed:increasing overlap ratio of SAR images, imaging from two directions and imaging on vertical direction. The effect of these methods in eliminating shadow are analyzed quantitatively. The reasons caused shadow by various terrains and possible eliminating methods are analyzed in Hengduan Mountain Region, and airborne SAR flight lines are designed in this area.4. A block adjustment model with few GCPs for airborne SAR is proposed. The model uses multi-photo united adjustment algorithm based on polynomial model with height displacement correction and F. Leberl imaging model. It is available for multi-scene SAR images with different looking side, flight height, resolution. According to multi-photo united adjustment model, software has been programmed. Additionally, experiments and improvement models have been done. The experimental results verified the 1:10000 scale topographic mapping block adjustment in plain and hilly terrain area.5. A direct positioning model with none GCP is put forward. Position and Orientation System (POS) data processing method is studied, including radar antenna dynamic eccentric correction and antenna phase center interpolation. Airborne SAR high-accuracy positioning method with none GCP is proposed which is based on high accuracy position and attitude data produced by POS. The model can satisfy 1:50000 scale topographic mapping through the experiment.6. The airborne SAR multi-strip block united geocoding model with few GCPs is brought up. The airborne SAR multi-strip block united geocoding algorithm is studied, including coarse positioning of single flight strip, airborne SAR multi-strip block adjustment and fine positioning of single flight strip. The GCPs layout plan of airborne SAR multi-strip block is brought forward as well.更多还原