Research On High Sensitivity Satellite Navigation Receiver Technology Based On SOC

With the extensive use of Global Navigation Satellite Systems in many fields,users have higher demands for the performance of satellite navigation receivers.In remote working scenarios such as navigation,exploration,and forestry,satellite signals will be greatly attenuated due to the effects of ionospheric refraction,multipath interference or building occlusion.The general satellite navigation receiver will face problems such as difficulty in capturing satellite signals,high synchronization error rate and easily out of lock.Therefore,research on high-sensitivity satellite navigation receivers that can capture weak satellite signals are required by society.Compared with other programmable platforms,SOC platforms have the advantages of higher integration,smaller size,and lower power consumption.This can broaden the application fields of satellite navigation receivers and enhance China's strength in the field of satellite navigation.This paper studies the SOC-based high-sensitivity satellite navigation receiver technology.First,the signal structure and navigation message frame format of the three satellite systems: GPS,GLONASS,and BDS are analyzed respectively.Then the chip select and hardware architecture of the receiver are introduced.Then,on the premise of analyzing the principle of satellite signal acquisition and tracking along with the influencing factors that weaken the satellite signals,several integration methods to improve the signal-to-noise ratio of signals and weak signal acquisition algorithms to overcome navigation message bit reversal are compared and researched.According to the characteristics of the navigation messages of different satellite systems,different acquisition algorithms were developed,combined with the acquisition strategy of first rough acquisition and then subtle acquisition,the Doppler frequency shift and the pseudo code phase of the weak signal of the three system satellites were achieved.After the analysis of the carrier tracking loop and code tracking loop is completed,it was decided that the weak signal tracking loop adopts the carrier loop assisting code loop method.Through the cooperation between frequency-locked loops and phase-locked loops of different orders,weak signals of three satellite systems are tracked stably and continuously.Finally,in order to solve the problem of high error rate of weak signal bit synchronization,an algorithm to improve the accuracy rate of weak signal bit synchronization is adopted,and the algorithm is applied to different satellite systems.The actual test of the receiver proves that the method applied in this article can achieve the expected goal.This high-sensitivity receiver can capture,track weak satellite signals of the three systems and locate.The capture sensitivity of each system can reach-143 d Bm,and the tracking sensitivity can be up to-140 d Bm,meeting the needs of users for high-sensitivity receivers.Through the above research,improving the signal-to-noise ratio of the signal and solving the weak signal tracking problem can achieve the receiver's acquisition and tracking of the weak signals.