Research On The Vehicle Positioning Algorithms Based On GPS Signal And Information Effectiveness Evaluation

Global Positioning System(GPS),developed in the United States,is the most widely used satellite navigation system in many military and civilian fields,especially in the field of vehicle trajectory tracking.However,increasingly complex electromagnetic environment,dense urban buildings make it difficult to obtain accurate and real-time GPS signal,which reduce the accuracy of user positioning,or cannot provide position information.Hence,it is of importance to evaluate the validity of GPS signal and information,and do the research on vehicle trajectory tracking algorithm when GPS is outage.The performance evaluation of GPS signals and information is aimed at discussing the anti-jamming ability of GPS signal and information validity when GPS signal is disturbed.This paper mainly studies the anti-jamming performance of GPS signal according to characteristics of GPS Receiver Tracking loop,and proposes anti-jamming performance analysis method of GPS signal anti-jamming threshold Jamming to Signal Ratio(JSR)based on tracking threshold.The influence of anti-jamming coefficient on anti-jamming threshold under different Electromagnetic Interference(EMI)is analyzed.Because the anti-jamming index of GPS signal can only reflect the anti-jamming ability of the receiver under normal operation,it does not consider whether the positioning information affected by the interference is still credible.In order to judge whether the information of GPS receiver is available under electromagnetic interference,this paper proposes an information availability detection method based on model updating,which uses the modified model to get a new sum of squares of errors to judge the availability of GPS information.The anti-jamming ability and information availability of GPS signal are verified by simulation.In order to achieve stable vehicle trajectory tracking under electromagnetic interference and sheltered building occlusion,the key to stable trajectory tracking is to solve the problem that GPS cannot provide effective positioning information for vehicles.Miniature Inertial Measurement Unit(MIMU),which has small size,low cost,and can complete the positioning task independently,can be adopted as a standby positioning system for vehicles when GPS fails.However,the low cost MIMU gyroscope measurement error is large,which will cause the divergence of positioning error.In order to solve this problem,a positioning error suppression algorithm based on gyroscope measurement error prediction is proposed in this paper.In the effective stage of GPS,the gyroscopic measurement error is estimated by using the information provided by GPS.At the same time,the artificial neural network is used to learn the variation law of gyroscopic measurement error,and the gyroscopic measurement error model is established.At the failure stage of GPS,the gyroscopic measurement error model is used to predict the gyroscopic measurement error,and the gyroscopic measurement error is compensated,which can limit positioning error.The correctness of the algorithm is verified by simulation,and the effectiveness of the algorithm is verified by experiments based on MTi-G710,produced by XSENS Company in Netherlands.The simulation and experimental results show that the trajectory tracking algorithm based on gyroscope measurement error prediction proposed in this paper can effectively suppress the positioning error under GPS failure stage.This paper evaluates the performance of GPS by evaluating the anti-jamming ability of GPS signal and judging the availability of receiver information,and realizes the stable trajectory tracking of land vehicles under the failure state of GPS,which has certain theoretical basis and practical application significance...