A map matching method for mobile phone base station positioning was put forward in the article.The accuracy of Cell-ID positioning was improved with linearity weighted algorithm at first.Then the map matching was accomplished with factors such as historical information,distance and angle.Some data was collected and analysis.It was proved by experiment that the method of map matching could be used in base station positioning in urban area where the distribution of base stations is dense and it would be more suitable for LBS.

A model of direction calculation based on point group dividing is proposed.This model quantitatively calculates the direction of spatial targets by dividing the point groups resulted from discretization of spatial targets.A case study is designed to verify the model.It can be concluded that the model is feasible and fairly efficient.It can meet the calculation requirements of geographical information systems and can support spatial data retrieval and query well.

In recent years, Global Navigation Satellite Systems Reflectometry (GNSS-R) is developed to estimate soil moisture content (SMC) as a new remote sensing tool. Signal error of Global Positioning System (GPS) bistatic radar is an important factor that affects the accuracy of SMC estimation. In this paper, two methods of GPS signal calibration involving both the direct and reflected signals are introduced, and a detailed explanation of the theoretical basis for such methods is given. An improved SMC estimation model utilizing calibrated GPS L-band signals is proposed, and the estimation accuracy is validated using the airborne GPS data from the Soil Moisture Experiment in 2002 (SMEX02). We choose 21 sites with soybean and corn in the Walnut Creek region of the US for validation. The sites are divided into three categories according to their vegetation cover: bare soil, mid-vegetation cover (Mid-Veg), and high-vegetation cover (High-Veg). The accuracy of SMC estimation is 11.17% for bare soil and 8.12% for Mid-Veg sites, much better than that of the traditional model. For High-Veg sites, the effect of signal attenuation due to vegetation cover is preliminarily taken into consideration and a linear model related to Normalized Difference Vegetation Indices (NDVI) is adopted to obtain a factor for rectifying the “over-calibration”, and the error for High-Veg sites is finally reduced to 3.81%.

Cellular network has low accuracy and GPS in complex environment has insufficient information, aiming at the irresistible detects in respective positioning system, present combined positioning method based on the GPS and cellular network, to improve the availability of the positioning, and improve the positioning accuracy. And the main factor of current effect on GPS / cellular hybrid positioning is non-line-of-sight propagation ( NLOS ). In this paper, based on the two scatter model inhibition of NLOS propagation effect, the idea is to transformed the NLOS error into a deterministic model factors, so the precision is mainly depends on the orientation of the measuring accuracy of the parameters and unrelated to non direct wave caused by parameter deviation, take scatter as a virtual base station, inhibition of cellular NLOS error, and auxiliary GPS positioning, to improve the dilution of position ( DOP ), namely in the GPS blind auxiliary positioning, further improving GPS / cellular hybrid positioning accuracy. Through the static, movement, ROS model, Gauss noise propagation environment, and use of error cumulative density function and RMSE to evaluate algorithm for hybrid positioning in this paper, the result has higher accuracy and stronger robustness.

提出利用虚拟现实技术加强对导航卫星星座的三维仿真模拟,用于系统的设计与监控。考虑到GPS系统的成熟性和与北斗系统的相似性,以GPS精密星历为基础,深入研究利用GPS精密星历拟合卫星三维坐标的方法,对两种常用方法——拉格朗日多项式内插和切比雪夫多项式拟合的处理效果进行分析和比较,给出两种拟合方法得到的卫星位置误差与阶数的关系,探讨短时间外推的效果,确定切比雪夫多项式拟合为最佳的卫星轨道拟合方法,并据此求得任意时刻的卫星坐标,构建了导航卫星三维标准化轨道虚拟运行场景。

A kind of Cell-ID positioning method is put forward based on linear weight and Google base station database.All of the signal strength and position of the base stations received by the mobile terminal are utilized and it only needs to update the software of the terminal.The result shows that the accuracy is less than 150 m under 2σ circumstances and it is more suitable for LBS.

Using the monitoring system constructed with GPS to locate, track and schedule moving goods can effectively improve the utilization rate of moving goods and the level of information management. Traditional monitoring system is constructed based on the integration of GPS and information transmission system such as GSM, which can't fully control the state of moving goods for only a little information such as position, velocity can be obtained. The monitoring scope is also limited by the C/S (Client/Server) mode between the user and the monitoring center. In this paper, the related technology of the Internet of Things, the function of positioning and communication of COMPASS and the open Google Map service are analyzed. The key technology and implementation methods of hardware integration and software design of monitoring terminal, formatted information transmission and hardware configuration and software design of monitoring center are researched and described. A new B/S (Browser/Server) scheme compromising the COMPASS and related technology of the Internet of Things to monitor and schedule moving goods is put forward. It makes up insufficient aspects of traditional monitoring system and provides important reference and practical value for the application of COMPASS in related fields of the Internet of Things.

In order to promote innovation and development of domestic spacecraft system simulation technology,the authors developed GPS simulation system framework using virtual reality technology.With Matlab simulation,the method of constructing correct three-dimensional simulation orbit through processing the SP3 ephemeris data was obtained and verified.A real-time interactive three-dimensional visual simulation environment was realized.The test result was good and it could be beneficial to GPS designing and monitoring.