Research And Application Of GNSS Network RTK High Precision Position Method

The continuous development of the Global Navigation Satellite System makes the production and living more efficient.The emergence of network RTK(Real-Time Kinematic)technology breaks through the limitations of the traditional RTK technology and making the RTK technology widely used in traditional industries.Therefore,studying and improving the RTK key algorithm and developing related software can promote the development and application of RTK technology.At the same time,with the wide application of railway communication tower,designing a high-precision tower inclination measurement method can play an important role in ensuring railway transportation safety.This paper has carried on the related research and the software development to the positioning method and its application using the network RTK.In-depth studied the double difference mathematical model in the carrier phase differential positioning.And the principle and workflow of virtual reference station technology are expounded.The calculation models of virtual observation value and error correction number are deduced in detail.And realized the differential data transmission link,including Ntrip protocol client implementation and RTCM SC-104 message decoding.This paper has studied and simulated the key algorithms in RTK positioning.Based on the further study of the cycle slip detection and repair method,the ionospheric residual method is used to improve the Turbo Edit combination method.The experimental results show that the improved method can overcome the shortcomings of the original method,for the small cycle and special combination of dual-frequency cycle slip can be correctly detected and repaired.Then the process of solving the ambiguity is expounded,and the LAMBDA algorithm is studied emphatically.Experiments show that the method has good performance.On the basis of the algorithm research,a post-RTK calculation software is formed,and the experimental results show that in floating point solution mode,after long time observation can obtain the centimeter level positioning accuracy,but after ambiguity fixed,the positioning accuracy can quickly reach the centimeter level.Finally,the RTK technology is applied to the building dip measurement.In order to prevent the railway communication tower from tilting and collapsing,an RTK tower angle measurement method based on network RTK is designed,which can overcome the shortcomings of manual measurement methods.In this method,a measuring device is installed on the top of the tower.The device uses the 4G module to communicate with the CORS station to obtain differential data.The receiver acquires the satellite observation data.The obtained data were calculated by RTK software to obtain the position of the top of the tower coordinates,and then calculate the tower inclination.On the ground using iron simulation tower to experiment,verify the high accuracy of measurement results.