Method And Practice On Construction Of The Region Ground Based Augmentation Systems In BDS/GNSS

Beidou Navigation Satellite System(BDS)is the Global Navigation Satellite System developed and operated by China independently.BDS is officially announced in operation to Asia-Pacific region on December 27,2012;recently,performance of BDS is steady and steadily promoted;It will provide the world with navigation and positioning service in 2020.Continuously Operating Reference Station(CORS)is an important infrastructure of ground based augmentation system,can supply correction information and improving its navigation and positioning performance.The first GPS-CORS was established in Shenzhen,and after then GPS-CORS or GPS/GLONASS-CORS was constructed in most provinces or cities,such as Beijing,Shanghai,Guangzhou,Guangdong province and Jiangsu province.According to statistics,by the end of 2014,the number of CORS stations by all concerned departments of the country,provinces or cities is more than 2600,However,almost all of these CORS is based on GPS or GPS/GLONASS,and construction of BDS-CORS is almost none.Therefore,how to complete the promotion BDS-CORS which BDS is the predominant satellite from GPS-CORS or GPS/GLONASS-CORS,build the Ground Based Augmentation System on BDS and realize wide application is a problem which need to be deeply studied and practiced.In addition,how to effectively reduce repeated investment and enhance the use efficiency of the old CORS stations,how to realize co-construction and sharing of BDS-CORS stations from country and provinces by some construction mode and technical system,and how to realize the smooth transition from the present application services to BDS-CORS have become the focus and difficulty problems in the construction and application process of BDS-CORS.Firstly,system structure,service contents and index of BDS/GNSS(BDS/GNSS GBAS)is put forward and key technical system of it is given.Secondly,an overview of regional precision positioning technology by BDS/GNSS is presented and building methods of regional BDS/GNSS GBAS are deeply researched.The methods that upgrade strategy from GPS CORS or GPS/GLONASS CORS to BDS/GNSS GBAS,upgrade method of CORS station,solution of antenna radome problem of reference station,and realization coordinate datum are mainly studied.The real-time service systems of coordinate datum is studied systematically,and a new real-time service system of coordinate datum based on CORS/GBAS is designed and developed,which make it general,safe,and real-time.Finally,based on the building methods of regional BDS/GNSS GBAS former studied,GuangDong province BDS/GNSS GBAS was established and its performances were widely analyzed.Based on BDS/GNSS GBAS,Real-time coordinate datum service platform has been bulit,which make achievements of application coordinate and national vertical datum real-time obtained based on GuangDong province BDS/GNSS GBAS.Main contributions and innovative achievements of this dissertation paper include:1)System structure,service contents and index of BDS/GNSS(BDS/GNSS GBAS)is put forward and key technical system of it is given2)Current status of regional BDS/GNSS GBAS has been thoroughly reviewed from aspects of NETRTK technology,precise positioning method as well as PPP-RTK.Deep discussion and study have been made on the improved ambiguity solution for URTK using regional GBAS information;improved ambiguity resolution for URTK with dynamic atmosphere constraints has been put forward in this paper,which is confirmed by improving the success rates of AR for 10-20%compared to that of the WL-L1-IF one.3)Establishing methods of regional BDS/GNSS GBAS are deeply researched.And the methods that upgrade strategy from GPS CORS or GPS/GLONASS CORS to BDS/GNSS GBAS,upgrade method of CORS station,and realization of coordinate datum are mainly studied.4)Antenna radome problem which make coordinate of reference stations changed is discovered,and solution of eccentric observation is discussed.The coordinate updating problems of single station caused by antenna replaced are studied and solved,which guarantee continuity of coordinate reference frame and continuous and normal operation in the process of CORS updating.5)The system structure and application service technology in modern service systems of coordinate datum has been studied.A new method of transformation parameters encryption including parameters decomposition grid correction has been put forward in this paper,which solves the encryption problem of service end,data transmission and user end,in the service systems of coordinate datum transformation.6)Realization flow and equation expression for parameters decomposition grid correction have been rigorously deduced,and a new real-time service system of coordinate datum based on CORS/GBAS has been designed and developed,which make the system general,safe,and real-time.7)Based on the building theoretical method of regional BDS/GNSS GBAS former studied,GuangDong province BDS/GNSS GBAS was established and its performances were widely and systematically analyzed.Based on BDS/GNSS GBAS Real-time coordinate datum service platform has been bulit,which make achievements of survey datum highly fusion applied.