【作者】 佘世刚；

【导师】 黄欹昌；

【作者基本信息】 兰州大学 ， 无线电物理， 2008， 博士

【摘要】 地球重力场的精确测量对大地测量、地球物理、地球动力学和海洋学等学科的发展具有极其重要的意义。利用卫星对地球重力场进行测量具有划时代的意义,是当今大地测量领域的研究前沿和关注热点之一。国际上卫星重力场测量主要有三种模式,即高低卫卫跟踪（SST-h1,如CHAMP卫星）;低低卫卫跟踪（SST-11,如GRACE卫星）;卫星重力场梯度测量（如GOCE卫星）。其中低低卫卫跟踪技术是地球重力场测量最有价值和应用前景的方法之一。低低卫卫跟踪重力场测量卫星包括三大有效载荷,即高精度加速度计、双频GPS接收机、高精度K频段星间测距系统（KBR,K Band Ranging System）。其中高精度加速度计、双频GPS接收机,国家在计划中已经投入了大量财力和人力进行预研,取得了一定的成果,而KBR系统的研究因为各种原因仍处于研究阶段。KBR系统所需达到的微米量级测量精度使其成为测距技术的制高点,美国用了20多年时间才研制成功,目前处于高度保密状态。由于系统非常复杂、技术难点多,在我国KBR系统还没有成熟产品。因此,能否研制出星间高精度KBR系统是我国重力场测量卫星能否成功的瓶颈之一。在KBR系统中,作为频率基准的超稳晶振（USO,Ultra-stable oscillators）的技术性能对系统测量精度的影响至关重要,当前国内的技术水平与应用要求相比差距还很大,需要重点攻关突破。本文在研究国内外有关卫卫跟踪（SST,Satellite-to-satellite tracking）技术的基础上,针对现实需要,对用于我国重力场测量卫星的KBR系统方案进行了研究,并提出了关键技术,对关键技术之一——USO进行了深入研究,研制出了满足我国重力场测量卫星使用的USO。本文所研究的主要内容和相关结论如下:1.介绍了卫星重力场测量的基本原理及主要方法。讨论分析了国际上现有的三种重力场测量卫星工作模式的特点,阐述了采用低低卫卫跟踪模式的原因及优点。2.深入研究了星间双单路微波测距原理,提出了一种用于我国重力场测量卫星的KBR系统设计方案,描述了KBR系统的主要结构,详细分析研究了KBR系统需要突破的七项关键技术,初步提出了各项关键技术的攻关途径;3.对影响KBR系统精度的各种误差来源进行了深入地分析,建立了误差仿真模型,并对各单项误差和系统总体误差进行了初步估算;4.介绍了星载双频GPS接收机的发展过程,分析了星载双频GPS接收机的关键技术及系统设计要点,对GPS接收机和KBR系统一体化设计平台进行了分析;5.在着重分析影响USO频率稳定度,特别是短期频率稳定度的各种因素的基础上,对超稳晶振的主要组成部分石英谐振器、振荡电路、恒温控制系统进行了优化设计,研制成功的USO短期频率稳定度指标达到5×10^-13/s（阿伦方差）,满足使用要求;6.对KBR系统低频倍频链路进行了研究,研制了用于KBR的八倍频器电路,经过测试,性能满足使用要求。本文的主要创新点为:1.在分析微波测距理论的基础上,提出了我国用于重力场测量卫星的KBR系统设计方案,该方案在全国重力场测量研讨会上得到了专家的认可。对需要突破的关键技术进行了研究和分析;2.对关键技术之一——USO进行深入研究,成功研制出满足我国KBR系统需求的USO和八倍频器,USO短期稳定度指标达到5×10^-13/s（阿伦方差）,远远超过了国内KBR系统研制初期提出的技术指标要求2×10^-12/s（阿伦方差）,达到国内领先水平。本文所作的KBR系统基础理论分析及关键技术之一——USO研究,促进了我国KBR系统自主研发进程。KBR关键技术的突破,不仅有利于我国重力场测量卫星的发展,同时对卫星编队飞行、卫星自主导航以及复杂系统设计、高稳定基准频率源、高精度测相等相关技术领域的发展都有深远的影响。更多还原

【Abstract】 The accurate determination of gravity field is essential to a variety of geophysical applications, including geodesy, geophysics, geodynamics and oceanographic. Among many methods to measure the Earth’s gravity field, the use of satellite date has become critically important. At present, there are 3 models in gravity field measurement: high-low satellite-to-satellite tracking （SST-hl, such as CHAMP satellite）, low-low satellite-to-satellite tracking （SST-ll, such as GRACE satellite） and satellite gravity gradiometry （SGG, such as GOCE satellite）. And among them, the SST-11 is one of the most promising and valuable methods in measurement of gravity field.The SST-11 of gravity field measurement consists of 3 payloads: High Accuracy Accelerometer, Dual-frequency GPS Receiver, High Accuracy KBR System （K Band Ranging System）. For High Accuracy Accelerometer and Dual-frequency GPS Receiver, China has put a lot of financial and human resources in the preliminary research, and achieved certain results. Due to various reasons, the research of KBR System is still in the initial stage. KBR System requires micron level measurement accuracy, which pushes it to the commanding height of ranging technology. The United States spent 20 years before the successful development of KBR System, which is now classified as high secret. KBR System is very complex and technically difficult, and there isn’t mature product in our country yet. Accordingly, the development of high accuracy KBR System is the bottleneck of our country’s gravity field measurement. In the KBR System, as the frequency base, the USO （Ultra-stable oscillators） ’s technical performance is essential to the system’s measurement accuracy, and the technical level lags greatly behind the application requirements in our country in this area.Based on domestic and international studies on SST, the paper did research on our country’s KBR System concept on gravity field measurement, and conducted in-depth research on one of the key technologies-USO. The main research contents and related conclusions are as follows:1. Introducing the theory and major methods of satellite gravity field measurement, and makes analysis of the 3 existing methods in the world, and also the reasons and benefits for choosing the SST-11 are analyzed.2. Making in-depth study on inter-satellite dual-one-way microwave-ranging theory, and put forwards the KBR System main structure used in the gravity field measurement in China, and makes detailed analysis of 7 key technologies which are needed to get breakthrough, and also provides initial methods to do that.3. Making in-depth analysis on various sources of errors affecting the KBR System, and establishes the error simulation model, and makes preliminary estimation on single or general system errors.4. Introducing the development of satellite-loaded dual-frequency GPS receiver, of which the key technologies and system’s designing methods are analyzed, and also analyzes the integrated platform of GPS receiver and KBR System.5. Making optimized design of USO’s critical components, including quartz crystal, oscillator circuit and constant temperature control system, on the basis of analysis on the factors affecting USO frequency stability. The successfully developed short-term frequency USO stability indicators have reached 5×10^-13 / s （Allan deviations）.6. Making study on the KBR system’s frequency multiplier circuit, and having developed 8 multiplier circuit used for KBR, and the results of test indicate that the requirements of the performance are met.The key innovative points of this paper are as follow:1. On the basis of Microwave-ranging theory analysis, the paper put forward the KBR System designing proposal for China’s gravity field measurement, and this proposal has been approved by related experts.2. Making in-depth research on one of the key technologies-USO, and successfully developed the USO and the 8 frequency multiplier, and USO short-term stability indicators reached 5×10^-13 / s（Allan deviations）, exceeding China’s requirement of 2×10^-12 /s（Allan deviations）.The key KBS System breakthroughs achieved in this paper are not only conducive to gravity field measurement satellite development in our country, but also have far-reaching influence on the satellite formation flying, satellite autonomous navigation, complex system design, high-stability frequency reference source, as well as high-precision measurement and related studies.更多还原