Design And Implememtation Of Double Differential Ground Positioning System Receiver

Global positioning system(GPS)plays an increasingly important role in our life.The study of GPS receiver has also been a hotspot in the field of navigation and positioning.The precision of traditional GPS standard positioning is restricted,even after the cancellation of SA(Selective Availability),its localization accuracy is also 25 meters.The differential positioning can effectively improve the positioning precision,but its key technology is from abroad,and the cost is very expensive.With the development of Beidou navigation and positioning system in our country,researching the highly localized differential receiver plays a fundamental role for the development of our country's navigation and positioning system.The goal of this topic is to develop low-cost and high-precision GPS positioning terminal products by the study of the original data from low-cost GPS development board,extracting the orbit parameters and time parameters of satellite coordinates,and improving the existing positioning algorithm based on the actual test,using Ublox LEA–6T GPS development kit Design and implementation of the differential receiver with high positioning precision.The specific work is as follows:This dissertation analysis the whole GPS system with the goal of calculating receiver position based on the GPS coordinate and time system for understanding the satellite positioning.Taking LEA-6T GPS development board as receiver to receive satellite signal,decoding the original ephemeris data form the output of receiver,extracting the perturbation parameters and Kepler parameters to calculate the instantaneous satellite coordinates by all of the parameters.Finally,calculating the coordinates of the receiver combining with the pseudorange from the development board's output.Aimed at improving the precision of GPS positioning,The simulation,analysis and calculation of the double difference relocation algorithm by adding the gaussian noise and linear noise shows that it can effectively improve the positioning precision of the GPS receiver.This dissertation analysis positioning accuracy based on the original data from GPS development board.It is necessary to collect the visible satellite information by using Ublox receiver and receive each satellite signal to noise ratio parameters.In addition,choosing the four best satellite to calculate the satellite coordinate combined with the output information of pseudorange,using the double difference relocation algorithm calculate receiver position,and analyzing its positioning results.