摘要：In order to improve the positioning accuracy of vehicles tracking system，a current statistical model is employed as the moving model of vehicles in this paper，and the map-matching algorithms based on the map-aiding location nearly chosen and angle of speed chosen are proposed to amend GPS positioning data. The algorithms find out the best matching road by making full use of the road geographic information of electronic map. The simulation results show that the vehicle tracking system has positioning accuracy besides the nature of navigation.
摘要：The semi-analytical（SA) approach is proposed for the fast determination of gravity field from GOCE observations，the first Core Mission of ESA's Living Planet Programme，which strives for the determination of a high-accuracy and high-resolution global gravity field model. Based on the application of FFT and introduction of the nominal orbit（circular，exact repeat orbit，uninterrupted measurement time series，and constant inclination)，the SA approach can recover the potential coefficients from large observations in short time. This method can give a fast diagnosis of GOCE system performance in parallel to the running of GOCE mission by comparing the estimated noise characteristics of the SGG time series with the gradiometer error PSD（prior). The performance of this method is evaluated using the simulated observations of the different cases（ideal and practical). The results in this paper show that this method can be applied to the practical cases of non-circular，non-repeat orbits and non-constant inclination in the time series of observations by the iteration algorithm，which can eliminate or weaken the approximation errors in the observation model. The test examples show that for the recovery of the high degree gravity field model，the optimal regularization parameter should be selected in the Kaula regularization technique.
摘要：文章首先介绍了个人移动定位导航的概念与研究现状及所面临的问题，然后引入移动Agent技术，并对其进行了概念与特征的介绍。提出了基于 Mobile Agent技术的个人移动定位导航设计方案。该方案集成了无线接入网技术，移动Agent技术，Web 服务技术等核心技术，采用了构件化任务封装与UDDI 注册管理Agent系统的解决思路。方案具有较好的构建性与可扩展性。最后总结了基于移动Agent技术的个人移动定位导航系统设计方案的一些优点，指出了移动服务向普适计算模式发展的必然趋势。
摘要：Water level variations in four natural lakes，Poyang，Dongting，Tai，and Chao，within the Yangtze River basin are studied using ENVISAT GDRs. The GDRs were edited using simple editing criteria and appropriate geophysical corrections applied. Altimeter-derived lake level variation time series were then generated and analyzed. The results of this study，which is the first of its kind in using data from ENVISAT missions over the Yangtze River basin in China，reveal that the water level changes in these four lakes directly reflect the water level of the Yangtze River and contribute to the floods and their associated disasters that usually occur in the middle and lower reaches of the Yangtze River.
摘要：Kriging interpolation is an important supplement method for the lack of high-resolution reference maps in geophysical field of earth（GFE) navigation. But its commonly-used ordinary Kriging，which corresponds to the premier of GFE as second-order stationary stochastic process，has low interpolation accuracy caused by the problems in its variogram’s calculation. As to the special circumstances，that the high-frequency sampling ability of the current magnetometers makes interpolation mainly considered between the distant surveying-lines，this paper suggests the convergence-Kriging interpolation method based on heading-redundancy measurement. After establishing the redundant average experimental variogram function（RAEVF) and assuming the theoretical models with the best fitting effect，the interpolation results come close to the real distribution. Numerical analysis shows that the proposed interpolation method can not only achieve high-precision interpolation results based on the reference maps even with noises，but also provide the criterion for setting the sensors’ sampling frequency in pre-survey phase.
