Research On BD-SBAS Ionosphere And Protection Level Algorithm

Today,with the highly developed science and technology,the global navigation satellite system(GNSS)has generated increasingly greater social value in the economic and military fields.The satellite based augmentation system(SBAS)developed on this basis has become a target for the development of various aviation giants and organizations with its wide application scope and low cost.In particular,it can greatly satisfy the requirements of the International Civil Aviation Organization(ICAO)on the four aspects of accuracy,integrity,continuity and availability of civil aviation,Therefore,many countries and regions have built up their own SBAS in order to give its wide range of users with higher accuracy and better integrity navigation services.Based on the above,it is imminent for China to develop its own satellite based augmentation system based on BDS(BD-SBAS).As an important source of error in the satellite based augmentation system,the ionospheric error has been paid more and more attention by experts and scholars at home and abroad.This thesis describes the calculation method and process of ionospheric error in the ground reference terminal and the user terminal,and made an analog simulation research by using the observation data provided by China continental tectonic environment monitoring network in March 2016,the key point aims at the influence of three point interpolation method and four point interpolation method on the grid ionospheric error.The calculation results show that under the same condition,four point interpolation method of ionospheric error value is generally less than the value calculated by three point interpolation method,and the smaller the grid is,the smaller the error value is.In addition,the level of integrity monitoring and protection level is an important index to measure the performance of navigation system,it has an irreplaceable important role in the satellite based augmentation system.It is elaborated in detail,and make simulation calculates for its algorithm,combining with monitoring data of Beidou satellite,and take emphases analysis research on the protected level standard of Mianxian and Wuhan.The experimental results show that the protection level of two areas can meet the requirements of route navigation and approach.