| GNSS is short for the Global Navigation Satellite System,which includingAmerican GPS,Chinese COMPASS and many other navigation satellite system.As ahigh-tech,GNSS has been widely used in the world,plays a huge role in agriculturalproduction and national defense construction.With the social development andprogress,every country in the world compete to develop their own navigationsystem,and strive to occupy a place in the future competition. Navigation andpositioning technology has become a symbol of the country’s comprehensive strength,therefore, research for the GNSS receiver’s technology and improving the positioningaccuracy has very important practical significance.In this paper, the status and applications of global navigation satellite systems wereintroduced, the development of a single point positioning technology were studied.Based on the research background,we propose the use of IGS urtral-rapidephemerides to improve positioning accuracy,and designed specific programs.Dataprocessing center Analysis and process the urtral-rapid ephemerides which providedby IGS,then transmits the correction data to GNSS reveiver by data conmmunicationchannel.GNSS reveiver use the correction data to get the final preciseephemerides,then we can improve the accuracy of real-time positioning by the finalprecise ephemerides.According to the design,we use the embedded technology to build a platform ofGNSS receiver.We select S3C6410developed by Samsung as the core of GNSSplatform,design the major portion and interfaces of the peripheral modules.In order tomeet the functional requirements of the receiver,we use the HG-TG02module toprovide navigation message and pseudorange value which is needed by real-timeprecision positioning.Then,the method was designed to get and progress all thedata.The AD3812module was used to connect the3G network,we completed thedrive with this module and modified the Dial-up tool.Then, Socket programmingwere designed for data reception and transmission networks.In terms of algorithms, this paper introduced several common satellite ephemerisinterpolation algorithms, analyzed and compared the result solved by different ordersof interpolation algorithms.According to the results, the Lagrange interpolation was selected. In addition, the paper make a detailed design of data broadcast channel,tasktype and message format. On the software side, we complete the intergration andprocessing of the original navigation data and the correction data which calculated byprecise ephemeris. Finally,we make test in the respect of network status andpositioning results to prove that our design is feasible and effective. |
