Research And Implementation Of Differential GPS Relative Positioning

The research on outdoor high-precision positioning technology based on satellite navigation system has developed rapidly in the past 30 years,and the positioning accuracy of differential positioning technology has reached centimeters or even millimeters.However,differential positioning systems have not been widely used,mainly because the cost of differential positioning systems is too high.The key point and difficulty in differential positioning is to solve the carrier phase integer ambiguity.Generally,the multi-frequency multi-system receiver is used,which leads to the system cost being too high.The single-frequency receiver receives fewer GPS satellites,which makes it difficult to solve the integer ambiguity.Multipath interference and receiver noise are the main factors affecting th e accuracy of differential positioning and the efficiency of solving carrier phase ambiguity.In view of the above issues,this paper focuses on the following work.1.Research on differential GPS,with emphasis on the mathematical model and the solution of the carrier phase ambiguity.2.Research on anti-multipath GPS antennas,and propose low-cost,miniaturized anti-multipath GPS antennas to effectively suppress the influence of multipath interference on positioning accuracy.3.Research on high-performance GPS receiver design,GPS receiver sensitivity is the core indicator of receiver design.According to the improved noise theory,the receiver sensitivity is close to the physical limit of the chip.4.For the problem that the number of satellites received by the single-frequency GPS receiver can not achieve outdoor positioning under occlusion,the GPS and inertial navigation sensors are combined and the actual test is verified,which effectively improves the effectiveness and stability of the system.5.The differential GPS system is applied in the orientation measurement direction.For the application scenario of fixed short baseline,an algorithm for quickly solving the carrier phase ambiguity is proposed.Based on the above work,this paper achieved the following res ults.The combination of differential GPS positioning and orientation measurement has been successfully applied in the positioning system of the smart snow blower,achieving high-precision relative positioning and orientation measurement.The differential GPS technology is successfully applied to the base station antenna engineering reference measurement system,which can quickly and accurately solve the carrier phase integer ambiguities and achieve high-precision base station antenna azimuth measurement.The low-cost,high-precision differential GPS relative positioning system proposed in this paper contributes to the promotion and application of differential GPS technology and has high practical value.