GPS信噪比用于潮位变化监测研究

发布时间：2018-08-03 07:19

【摘要】：海平面变化直接影响全球天气及长期气候的演变,是环境科学关注的重要问题之一。与此同时,海平面变化也是地球动力学、动态大地测量及海洋测绘研究的重要内容,它关系到全球高程基准的统一,也是现代空间大地测量技术的重要研究内容。随着GNSS(Global Navigation Satellite System)研究与应用的不断深入,基于多路径效应的GNSS-MR(Global Navigation Satellite System Multipath Reflectometry)反演技术用于地表环境监测(植被、土壤湿度、雪深、海平面、火山等)已成为一种新兴的遥感手段。本文从GPS多路径和信噪比的关系着手,研究了GPS-MR技术监测水面变化的理论和方法,并基于GPS-MR技术获取了区域平均海面,验证了GPS信噪比监测海平面变化的可行性。论文主要研究内容和创新点如下:1.探究了GPS多路径产生的原因、时空特性以及对GPS天线设计的影响,并对GPS反射信号的极化方式、反射面的反射系数等进行了研究。给出了GPS信噪比的概念,分析了信噪比序列的特征及影响因素。在此基础上,详细分析了GPS多路径效应和信噪比的关系,并指出低高度角下信噪比SNR(Signal-to-Noise Ratio)受多路径影响严重,GPS多路径效应会直接影响GPS信噪比的变化,因此通过SNR的频谱分析可获取引起GPS多路径反射的地表环境参数。2.研究了基于信噪比观测值的GPS-MR技术进行水位探测的函数模型,并对信噪比残差序列的提取方法、有效卫星弧段的选取进行了讨论,提出了判断LSP(Lomb-Scargle periodogram)频谱分析得到的垂直反射距离是否有效的标准,通过菲涅尔反射区的理论分析了GNSS测站反演潮位变化的范围。通过算例,利用GPS-MR技术对湖面、有潮汐日变化的海面分别进行了水位变化的反演,验证了GPS-MR技术应用于水位变化监测的有效性,还分析了GPS-MR技术用于湖面和海面反演精度不同的原因。证明了岸基CORS(Continuously Operating Reference Stations)站在一定程度上可作为验潮站的补充。3.介绍了海洋潮汐和区域平均海水面获取的基本理论,给出了GPS-MR技术获取区域平均海水面的方法。通过算例分析,验证了GPS-MR技术在获取区域平均海水面时有着较高的精度,发挥了岸基CORS站在海平面变化监测中的应用价值。
[Abstract]:Sea level change directly affects the evolution of global weather and long-term climate, which is one of the important issues of environmental science. At the same time, sea level change is also an important part of geodynamics, dynamic geodetic surveying and marine surveying and mapping research. It is related to the unification of the global elevation datum and the importance of modern SPATIAL GEODETIC technology. With the continuous research and application of GNSS (Global Navigation Satellite System), GNSS-MR (Global Navigation Satellite System Multipath Reflectometry) inversion technology based on multipath effect (Global Navigation Satellite System) is used for surface environmental monitoring (vegetation, soil moisture, snow depth, sea level, volcano, etc.) and has become a new remote sensing hand. From the relationship between GPS multipath and signal-to-noise ratio, this paper studies the theory and method of monitoring water surface change by GPS-MR technology, and obtains the regional average sea surface based on GPS-MR technology, and verifies the feasibility of monitoring sea level change by GPS signal-to-noise ratio. The main contents and innovation points of this paper are as follows: 1. the reasons of GPS multipath generation are explored. The space-time characteristics and the influence on the design of the GPS antenna are studied. The polarization mode of the GPS reflection signal and the reflection coefficient of the reflector are studied. The concept of the GPS signal to noise ratio is given. The characteristics and the influence factors of the signal to noise ratio sequence are analyzed. On this basis, the relationship between the GPS multiplex diameter effect and the signal to noise ratio is analyzed in detail, and the low altitude angle is pointed out. The lower signal-to-noise ratio (SNR) (Signal-to-Noise Ratio) is seriously affected by multipath, and the multipath effect of GPS will directly affect the change of the signal to noise ratio of GPS. Therefore, the surface environment parameter.2. that causes GPS multipath reflection can be obtained through the spectrum analysis of SNR, and the function model of the water level detection based on the signal to noise ratio observational value GPS-MR technology is studied and the signal to noise is used. The extraction method of the residual sequence and the selection of the effective satellite arc are discussed. The standard of determining the validity of the vertical reflection distance from the LSP (Lomb-Scargle periodogram) spectrum analysis is proposed. Through the theory of the Finel reflection area, the range of the inversion of the tidal level is analyzed by the GNSS station. By an example, the GPS-MR technique is used for the lake surface. The water level of the tidal diurnal variation is retrieved respectively. The validity of the GPS-MR technology applied to the monitoring of the water level change is verified. The reasons for the different inversion accuracy of the GPS-MR technology are also analyzed. It is proved that the shore based CORS (Continuously Operating Reference Stations) station can be used as a tide test to some extent. The supplement.3. introduces the basic theory of ocean tide and regional average sea surface water surface acquisition, and gives the method of obtaining the average sea surface of the region by GPS-MR technology. Through an example analysis, it is proved that the GPS-MR technology has high precision in obtaining the average sea surface surface of the region and exerts the application value of the shore base CORS station in the sea level change monitoring.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4;P229

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