1、而海洋变化的空间尺度可以从几毫米到几万公里;时间尺度从几分钟到几千年。随着空间技术的进步,在过去20多年中,海洋观测卫星在数量和种类上都有了很大进步,与传统海洋观测相比,卫星遥感具有投资少、监测能力强、覆盖面积大、全天候、全天时的特点,使人们研究和认识海洋的手段有了突飞猛进的发展。随着陆地资源的日益匮乏,21世纪的人类必将更大的注意力转向海洋区域,为此必须对海洋有更深入,更全面的了解。过去依靠船只、验潮站和浮标等技术所获得的观测数据具有测量数据稀疏、重复周期长、花费较大等缺点,而星载高度计的出现以其投资少、检测能力强、覆盖面积大、全天候、全天时的优点将海洋观测带入了一个新的领域。星载高度计已经
2、成为现代海洋测量的基本观测仪器之一,在海平面测量、海洋潮波系统、海洋风浪场反演的方面都有大量的应用。其潜力和应用价值也是不可估算的。本文在研究星载雷达高度计工作原理的基础上,对数字处理器部分的主要组成部分跟踪器进行了研究,主要有以下成果:1. 对星载海洋高度计的基本工作原理作了解,对进入数字处理器之前的信号处理过程进行了分析,包括Chrip信号的发生和重触发,全去斜坡处理以及之后进行的A/D转换等。2. 对数字处理器的主要组成部分跟踪器进行深入研究和分类。跟踪器由高度跟踪环(HTL)、有效波高跟踪环(STL)、自动增益跟踪环(AGCL)组成。三个环所采用的估算方法是以最大似然估计(MLE)为基
3、础的准最大似然估计(SMLE)。所有的环路滤波器均为二阶低通型一滤波器。3. 分析海面回波的处理仿真过程。分析基于布朗积分解法的回波平均功率表示。4. 跟踪算法的分析与仿真设计。星载雷达高度计采用准最佳最大似然估计算法(SMLE)作为跟踪算法。本文对准最大似然估计算法进行了研究和分析,并在此基础上对星载雷达高度计的跟踪过程进行了仿真。关键词:星载雷达高度计;回波处理;跟踪算法;准最大似然估计算法Abstract:The 21st century is the century of sea, land on Earth with the increasing scarcity of resour
4、ces, to maintain the sustainable development of mankind, more comprehensive and profound understanding for ocean are needed. In the past, the research formore than 70% of the total area of the world can only rely on tracking ship, such as tide observation stations and data buoys, but the data are sp
5、arse measured, the repeat cycle is long, and the cost is large, providing only the access to local area data. Changes in the spatial scale of the ocean ranges from a few millimeters to tens of thousands of kilometers; time scales ranges from minutes to thousands of years. With the progress of space
6、technology in the past 20 years, marine observation satellite developed on both the number and variety , compared with the conventional ocean observation, satellite remote sensing comes with less investment, larger monitoring capacity, coverage area, all-weather , all-time, bringing the huge improve
7、ment in the understanding of the ocean. With the increasing scarcity of land resources in the 21st century,people will surely pay greater attention to ocean areas, for which there must be deeper and more comprehensive understanding of the ocean. In the past, we rely on ships, and buoys, tide gauge t
8、echnologies such as the observation data obtained with the measured data sparse, repeated long cycle, spending more shortcomings, and the emergence of satellite altimetry for its investment, detection capability, coverage area, all-weather, all-time advantage of the ocean observations into a new are
9、a. Satellite altimetry has become one of the basic observational instruments for sea level measurement, marine tidal wave system, and aspects of ocean wave field inversion. Its potential and value is highly estimated. Based on the study of spaceborne radar altimeter, this article studies the main co
10、mponent of the digital processortracking device. And the following results are showed:1. Make the understanding of the working principles of the satellite ocean altimeter, and I analysed the process of signal processing before the digital processor, including the occurrence and re-trigger Chirp sign
11、al, all to ramp processing, and the A/D conversion after it.2. The study in depth and classification of the main components of the digital processortracking device. It consists of the height tracking loop(HTL), significant wave height tracking loop(STL), automatic gain tracking loop(AGCL). These thr
12、ee loops use the estimation method based on maximum likelihood estimation(MLE)-based similar-maximum likelihood estimation(SMLE). All of these loop filters are type 一 low-pass filter.3. Analyse of the processing simulation of the received wave. Also analyse the average power of the received wave bas
13、ed on Brown integral solution.4. Analysis and simulation of the tracking algorithm. Spaceborne radar altimeters use similar-maximum likelihood estimation(SMLE) as the tracking algorithm. This article aimed at the study and analysis of the SMLE, and based on which the tracking process is simulated.Ke
14、yword: Spaceborne Radar Altimeter; signal processing; tracking algorithm; similar-maximum likelihood estimation algorithm. 目录第一章 绪论1.1课题背景及意义 21世纪是海洋的世纪,随着地球上陆地资源的日益匮乏,人类为维持其可持续发展,需要对海洋更全面、更深刻地了解。随着空间技术的进步,在过去20多年中,海洋观测卫星在数量和种类上都有了很大进步,与传统海洋观测相比,卫星遥感具有投资少、监测能力强、覆盖面积大、全天候、全天时的特点,使人们研究和认识海洋的手段有了突飞猛进的发展1。1.2 星载雷达高度计的国内外基本研究情况 卫星测高研究计划最早可追溯到1969年在威廉斯敦召开的固体地球和海洋物理大会,经过数十年的发展,大致经历了从探索、试验到应用研究及业务使用阶段的发展历程。在高度计发展的探索阶段,首先是利用搭载在Apollo 14上的高度计对月球进行了探测,随后是1973年Skylab上的高度计对地球的观测。在探索阶段高度计的观测精度非常低,Skylab的测高精度约为1m,测波精度12m。因此,很难满足海洋应用的需要。
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