标题: | GPS基线计算之对流层延迟修正研究 A Study on Tropospheric Delay Corrections in GPS Processing |
作者: | 刘至忠 Jyh-Chung Liu 陈春盛 Chun-Sung Chen 土木工程学系 |
关键字: | 全球定位系统;Global Positioning System |
公开日期: | 1993 |
摘要: | 对流延迟效应可分为干、湿对流层延迟效应二种,由于地面气象资料无法 有效描述湿对流层之变化,造成湿对流层延迟效应难以有效修正;其对基线 成果之影响,分为绝对与相对二种,绝对误差影响基线尺度,相对误差影响 基线高程,其中以相对误差对高程之影响较大 ,使得全球定位系统高程误 差约为水平误差之2∼3倍。因为对流层修正模式颇多 ,不同之计算软体使 用不同之修正模式,究竟不同模式是否会对基线产生不同的结果,在不同之 测区使用何种模式较适切,以及就目前较佳之计算方法能达到何种等级之 精度 ,为本研究之主要目标。在本研究中,吾人从中央研究院地球科学研 究所设立之GPS连续记录固定站之资料,选择二条不同距离及高程差之基 线(S01R-S101 ,S105-S104),针对Saastamoinen、Modified Hopfield、 Essen-Froome三种常用之修正模式及测站附加参数法与实测地面气象资料 、标准气象模式加以分析比较。基本上,Saastamoinen与Modified Hopfield二种模式之差异极微,在基线较长时宜利用实测地面气象资料,可 获得较佳之成果 ,在高差较大时,宜选用Essen-Froome模式,所得成果较精 确,利用实测地面气象资料和测站附加参数法吸收对流层残余误差 ,则可 使相对高程精度达到2公分以内,为目前较佳之处理方法。 The tropospheric delay can be divied into the "dry" delay and the "wet" delay, owing to the wet term is more spatially and temporal varying than the dry term, thus is more difficult to model from surface meteorological data. The infiuences on GPS baseline result can be divied into two classes, the abso- lute and the relative tropospheric biases. The relative tropo- spheric biases introduce the height's biases into GPS baseline result, and is bigger than the absolute term in GPS relative positioning. Hence, the precision in height is 2-3 times the horizontial on Global Positioning System. Many troposphere models had been proposed, and different model in different GPS processing software. Which model will better fit in different case, and which order of precision in ifferent model, it is the aims in our study. We choose two baseline in different length and height from continuous-moni- toring GPS stations in the the Insititude of Earth Sciences, Academia Sinica. Three models for the troposphere,Saastamoinen、Modified Hopfield、Essen-Froome, will be tested using meteo data of observed and extrapolated from standard meteo model, and analyze the parameters estimated method for the tropo- spheric delay. Basically, the model of Saastamoinen and Modified Hopfield are almost identical. Using surface meteo data wwill get a better accuracy result in longer baseline; The Essen-Froome's model is more suitable in larger height difference's baseline. We obtain an magnitude of about 2cm in GPS height's precision by using parameters with observed meteo data to absorb the residual error of tropospheric delay. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#NT820015057 http://hdl.handle.net/11536/57577 |
显示于类别: | Thesis |