Research On The Key Techniques Of GPS Receiver And Its Applications

At present,GPS has been applied in a lot of fields including military affairs, navigation,aviation,survey,traffic,and reconnaissance,which involve all human activities associated with position,velocity,and time.Since the very beginning of the establishment of GPS system,the research on techniques of GPS receiver and its applications is becoming increasingly popular in the world,and some achievements of the key techniques in this field have been made in China.Based on current trends and hot topics of GPS receiver and its applications,this paper focuses on key techniques which include incomplete constellation positioning algorithm,receiver autonomous integrity monitoring,electromagnetic compatibility design for receiver application, embedded GPS receiver implementation technology,and so on.Moreover,several novel algorithm and practical design are proposed.And some valuable results are obtained.The main contributions of this thesis can be summarized as follows:1.Aiming at the poor positioning feature under GPS incomplete constellation environment,the altitude estimating algorithm is investigated,and its modification which aids the receiver to positioning is put forward.With the weighted altitude added into the navigation equations,they can be solved properly.Meanwhile,the clock bias forecast model is proposed.With the help of health-clock- bias calculated value,the estimated clock bias can be applied in the GPS equations to assist the GPS receiver to keep positioning within short time.The validation and analysis based on the real GPS data shows that the two kinds of methods can both enhance the availability of GPS positioning.2.The receiver autonomous integrity monitoring(RAIM) algorithm for satellite fault detection and isolation is deeply analyzed.In order to overcome the shortcomings of current RAIM algorithm,a new approach for RAIM,based Markov Chain Monte Carlo method and standard particle filtering,is presented.It can effectively detect and isolate the GPS fault satellite.Moreover,it can address the degradation of detection performance under non-Gaussian measurement noise.3.In allusion to the actuality of water safety monitoring system in our country and the contemporary problem in electromagnetic compatibility of various kinds of electronic or electrical equipments within the watercrafts,the shipborne terminal system is designed,moreover,both the factors causing electromagnetic interference and the transfer mode of the interference are investigated.Aiming at the problems occurred on the spot,some methods for EMC optimization are puts up.The shipborne terminal system has passed the testing of EMC measurement institution.The running results and experiments data show that the Electromagnetic Compatibility techniques used in the design of shipborne terminal system well ensure the system's long-term stable and reliable running.4.In order to fulfill the needs of shipborne terminal system,a method to design GPS receiver which based on one chipset produced by NemeriX company is given out. The experiments show that the whole design of the system is reasonable,and the performance indexes fulfill SPS users' demand perfectly.At the same time,GPS digital intermediate frequency signal may be extracted from the receiver,and it is both premise and base for further research of GPS signal processing.In addition,the configuration scheme and optimize plan for embedded GPS receiver are investigated,and successfully applied in the implementation of GNSS receiver based on FPGA.