【作者】 王晓英；

【导师】 宋连春； 曹云昌；

【作者基本信息】 南京信息工程大学 ， 大气遥感科学与技术， 2013， 博士

【摘要】 本文对地基GNSS技术层析对流层水汽场中的三个关键问题进行了研究。分别为探空数据缺乏地区大气加权平均温度Tm(Weighted Mean Temperature of Atmosphere)本地化模型的建立,迭代法代数重构技术解算层析方程的适用性和北斗+GPS卫星信号融合层析对流层水汽场。1.针对探空资料缺乏地区本地化加权平均温度经验公式无法建立的问题,研究了利用克吕金插值方法和再分析资料ERA-interim建立Tm-Ts(地面温度)经验公式的可行性,分析了分季节和全年Tm-Ts模型基本无差异的原因。研究发现Bevis模型在中国东北部和青藏高原地区较本地化模型更适用,且克吕金插值方法和再分析资料ERA-interim均可有效建立Tm一Ts本地化模型。2.针对最小二乘法LSM (Least Squares Method)解算层析方程存在巨型稀疏矩阵求逆困难,数据难以组织,输入值的微小变化易引起结果震荡等缺点,研究了迭代法代数重构技术ART (Algebraic Reconstruction Techniques)解算层析方程的适用性。已有基于斜路径湿延迟SWD (Slant Wet Delay)计算的评价参数δ和σ仅反映被斜路径穿过的格点精度,论文增加了基于整体格网层析结果的Bias和RMS评价参数,其较δ和σ参数能更全面地反映层析结果精度。基于δ, σ, Bias和RMS参数研究了迭代法乘法代数重构技术MART (Multiplicative Algebraic Reconstruction Techniques)解算层析方程时初始场、格网模型和高斯约束对层析结果的影响。研究表明初值误差越小,层析结果精度越高；采用基础格网模型和高斯内插可提高层析结果精度。基于模拟方法对MART和LST解算层析方程进行了比较,结果表明MART层析结果较LSM方法稳定。3.针对中国北斗导航卫星系统COMPASS (BeiDou Navigation Satellite System)当前蓬勃发展现状(已为亚太区域提供正式运行服务,截止2012年12月26日天上在轨卫星数已达16颗),研究了基于单北斗信号层析对流层水汽场的可行性和COMPASS+GPS信号融合对水汽场层析的改善效果。研究发现因COMPASS系统当前在轨卫星主要覆盖中国及周边地区,对于深圳香港GNSS实验网而言,使用到的九颗北斗卫星(PC01,PC03,PC04,PC05,PC06,PC07,PC08,PC09,PC10)可达到与现有GPS导航系统相当的有效信息量,大部分时段下,基于单北斗系统层析结果精度优于单GPS系统；当地面站点充分时,融合COMPASS+GPS信号对层析结果精度改善作用不明显。更多还原

【Abstract】 Aiming at the key problems that need to be solved in tropospheric water vapor tomography, the article makes studies on the set up of local model for weighted mean temperature of the atmosphere for areas lack of soundings data, the usability of MART for solution of tomography equations, and the fusion of signals from COMPASS and GPS navigation satellite systems for water vapor detecting.1. To solve the problem that the empirical formula of Tm-Ts cannot be set up for areas lack of soundings data, the Kridging interpolation method and reanalysis data ERA-interim have been developed respectively, the reason for no difference between the precison of seasonal and year Tm-Ts model is analized. The studies show that the Bevis Tm-Ts model is more suitable than local model in northeastern China and Qinghai-Tibet Plateau, furthermore both the Kridging interpolation method and reanalysis data ERA-interim are effective in the setting up of local Tm-Ts model for areas lack of soundings data.2. To avoid the trouble of matrix inversion and data organization in LSM, the paper discusses the usability of MART for solution of tomography equations. The existing δ and σ parameters calculated from slant wet delay can only evaluate the precision of the voxels penetrated by slant paths. The paper adds two new statistical parameters Bias and RMS, calculated from wet refractivity of the total voxels, to evaluate the precision of total grid more comprehensively than δ and σ. The paper discusses the effect of the initial field, grid model and Gaussian interpolation in MART on the tomography results based on δ,σ, Bias and RMS. The studies show that in order to obtain good tomography results, initial value should be obtained with accuracy as high as possible, good grid model containing more SWDs with high elevation angle should be designed and Gaussian interpolation method can be used to update the wet refractivity of voxels not penetrated by any SWD. The comparision between MART and LSM is given, indicating that the MART can achieve more stable tomography results than LSM judging from σand RMS.3. Chinese COMPASS satellite navigation system has been providing regional formal service for China and surrounding areas at the beginning of2013. By the end of August15,2012there are13on-orbit satellites. The improvement effect of infusion COMPASS+GPS signal on tropospheric wet refractivity tomography result and the feasibility of pure COMPASS system for tropospheric wet refractivity tomography are discussed for the first time. The findings show that because the now on-orbit COMPASS GEO and IGSO satellites are mainly covering China and surrounding areas, the effective SWDs from nine COMPASS satellites (PC01,PC03,PC04,PC05,PC06,PC07,PC08,PC09,PC10) are comparative to that from GPS. Infusion COMPASS+GPS signals can not improve the tomography result for Shenzhen and Hongkong GNSS network, and the precision of tomography result only using COMPASS signals is superior to that using GPS.更多还原