The Technique Research And Program Realization Of GNSS Multiple System For Medium-Long Baseline Solution

With the modernization of American GPS system,the return of Russian GLONASS system,the establishment of EU GALILEO system and the global networking of BDS-3 system in China,the combination of GNSS multi-system positioning will become an inevitable trend of navigation and positioning in the future,data fusion between multiple systems has also become one of the key technologies in GNSS combined baseline solution.Baseline solving technology can obtain high-precision positioning results,which has an irreplaceable position in GNSS positioning.It has been widely used in various fields,such as national defense,engineering surveying,deformation monitoring,and transportation,et al.GNSS medium-long baseline solution has a wider application prospect,the construction of high speed rail,large large cross-sea cross-river bridge and large tunnel engineering control network all have the demand of medium-long baseline solution.Realizing the medium-long baseline solution of GPS/BDS system combination will improve the fragility of single-system positioning and ensure the accuracy of positioning solution.It has important theoretical significance and engineering application value,and conducive to the promotion and application of China's BDS system.The main contents and conclusions of this paper are as follows:1.Aiming at the difference between GPS system and BDS system in time system and coordinate system,the unified theory of space-time system in GPS/BDS combined positioning is researched.Based on the derivation of GPS and BDS satellite coordinate calculation method,the main scheme of GPS/BDS combined positioning is further proposed.2.We studied the mathematical models of GPS/BDS combination positioning,such as non-difference,double difference,wide lane and ionosphere free.Introduce stochastic models based on satellite height angle model,SNR model,posterior variance estimation model.The error sources and their correction methods related to satellite,propagation path and receiver are also analyzed.3.The study of some key issues in the GNSS long-baseline resolution is realized,including the technique of cycle slip detection and repair by ionospheric residual method and M-W combination method.After the fixed width Lane ambiguity is built,the ionosphere free combination model is constructed.Based on the Kalman filter,the basic ambiguity floating point solution technology is solved,and the use of LAMBDA algorithm to achieve ambiguous floating-point solution fixed technology.4.This article based on the concept of object-oriented C++ platform,use the algorithm to develop a set of GPS,BDS and their combined system of medium-long baseline data processing software.Taking the medium-long baseline data of Hong Kong CORS network data and 3D moving deformation platform data as an example,to verify the algorithm.The calculation results show that 28.1km baseline RMS value in the X,Y directions are better than 13.0 mm,Z direction is better than 18.0 mm,49.9km baseline RMS value in X,Y direction is better than 16.0mm,Z direction is better than 25.0mm.The 3D mobile platform 20.8km,45.5km,and 63.6km six baselines of each system X,Y and Z directions RMS values are better than 3.0cm,3D movement distance mean square error is better than 24.3mm,relative mean square error is better than 1/55.8.