Research on the modeling of tropospheric delay in virtual reference station
Research on the modeling of tropospheric delay in virtual reference station
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Y. Xiong;Df Huang;X. Ding;H. Yin
中科院分区：
文献类型：
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作者：
Y. Xiong;Df Huang;X. Ding;H. Yin
大气延迟，包括电离层延迟和对流层延迟，是长距离运动定位的主要误差源之一。许多学者对此进行了大量的研究。大气延迟可以用仿真模型来模拟，如Hopfield模型和Saastamoinen模型。中性大气延迟严重影响了精确定位。虚拟参考站技术是减少大气误差对精确定位影响的有效方法。用户可以任意选择VRS(通常使用导航位置)的位置。现有的RTK处理软件可以应用于远距离RTK，如果使用VRS技术。VRS的关键问题是对大气延迟进行精确的建模。为了模拟电离层延迟，许多作者做了大量的工作，基于多个参考站的双频观测数据。由于对流层误差的复杂性，VRS中的许多工作都是基于多个参考站上的双频观测值。由于对流层误差的复杂性，VRS中的关键问题是对大气延迟的精确建模。由于对流层误差的复杂性，许多作者在多个参考站上基于双频观测值进行了大量的工作。由于对流层误差的复杂性，VRS中的关键问题是建立精确的大气延迟模型。现有的对流层延迟模型的精度不能满足精确定位的要求。在研究了对流层延迟与参考站海拔高度的关系后，提出了7种高度因子的对流层拟合模型，并通过两个实验对所提出的模型的精度进行了分析。研究结果表明，根据SCIGN部分网的数据，所提出的模型具有比传统方法更好的拟合精度。最佳拟合模型是由校验点确定的。拟合精度取决于已知点的数量及其分布和网的大小。基于对SCIGN网面积为60公里×60公里的部分网的测试，结果表明，所提出的模型具有较高的拟合精度高程为-20m~700m的4参数1高程多项式拟合模型对5个已知点的拟合精度最高，为±7.6 mm；对于500 km×300 km的区域，6点高程的精度约为±1.8 cm，5参数1高程多项式拟合模型的拟合精度最高。本文提出了一种外推方法，初步测试表明，外推精度约为±9.0 mm，需要进一步的实验，以检验所提出的模型在不同网络上的精度，这些网络的平均高差大于SCIGN的测试网络。
Atmospheric delay,including ionospheric delay and tropospheric delay,is one of the main error sources in the long distance kinematic positioning.Many authors have made great researches on this problem.Atmospheric delay can be modeled by a simulated model,such as Hopfield's model and Saastamoinen's model.Neutral atmosphere delay has badly affected precise positioning.Virtual reference station technology is an effective method to reduce the impact of atmospheric error on precise positioning.The location of VRS(usually using the navigation position) can be arbitrarily selected by user.Existing RTK processing software can be applied to long distance RTK if using VRS technology.The key problem in VRS is to model atmospheric delay precisely.For modeling the ionospheric delay,many authors have done great works based on double frequency observables on multi-reference stations~().Because of the complexity of tropospheric error,the accuracy of existing tropospheric delay models can not meet the requirement of precise positioning.After investigating the relationship between tropospheric delays and the elevations of reference stations,this paper presented seven troposphere-fitting models with height factors,and then analyzed the accuracies of proposed fitting models by two experiments.Research results show that the proposed models have better fitting accuracy than traditional method according to the data from part of SCIGN network.The best fitting model is determined by check points.The fitting accuracy depends on the number of known points and their distribution as well as the size of a network.Based on the test on part of SCIGN network with an area of 60 km×60 km,the height of which is from(-20 m) to 700 m,polynomial fitting model with 4 parameters including one height parameter has the best fitting accuracy(±7.6 mm) if using 5 known points.For an area of 500 km×300 km,polynomial fitting model with 5 parameter including one height parameter is the best one if using 6 points,the accuracy of which is about ±1.8 cm.For real time application,an extrapolating method was proposed by this paper.Initial test showed that the extrapolating accuracy is about ±9.0 mm.Further experiments need to be done in order to test the accuracy of proposed models in different networks with bigger average height difference than the test network from SCIGN.