Research On Theory Of Gbas Ground Station Siting Based On Multipath Analysis

The ground-based augmentation system(GBAS)is a system that provides GPS differential correction and integrity detection.The GBAS provides navigation and precision approach services near the airport(45 km radius),and transmits VHF radio data broadcast through ground-based transmitters(VDB)broadcast differential correction information.The location of the GBAS ground station is crucial to the installation and operation of the entire system.The multipath effect of the GPS satellite signal will affect the positioning accuracy of the GBAS reference receiver.The terrain and environment surrounding airport buildings and airports may cause multipath on VDB signals and affect signal coverage.Based on this article,the main research work is as follows.This paper introduces the principle of GPS single point positioning and further elaborates the principle of carrier smoothing pseudorange differential correction adopted by GBAS system.Based on the theory of radio propagation,the ground reflection multipath error of the GBAS reference receiver was modeled and simulated,and the main factors affecting the error were obtained,which theoretically guided the installation of the reference receiver.For the multipath effect that the GBAS reference receiver location and the physical scheme can not overcome,this paper proposes an extended empirical mode decomposition method(EEMD algorithm)for processing.According to the data verification of Bethel airport station,this algorithm has suppressed the multipath effect to a certain extent and improved the positioning accuracy(by 9%).Aiming at the installation scheme of VDB antenna,a method of using existing electromagnetic environment simulation technology was proposed to simulate and calculate the signal coverage intensity of key airports.At the same time,VDB signals are provided near the main airport to provide strength coverage detection for navigation and precision approach services to determine the optimal solution for VHF data broadcasting antenna installation.Through analysis and calculation,an antenna installation optimization solution is obtained.The experimental results show that the new method can optimize the antenna installation scheme and reduce the installation cost.At last,taking Bao'an airport in Shenzhen as the research object,the GBAS siting simulation study was conducted based on the site selection criteria and the actual airport environment,and the best location results were obtained.