Research On Received Algorithm Of GNSS L1 New Civil Signal

MBOC is a modulation signal adopted by GNSS L1 civil signals:Beidou B1 C,GPS L1 C and Galileo E1 OS.Compared with traditional GNSS L1 signals,MBOC has a longer signal code cycle which brings higher tracking accuracy and excellent anti-interference,but it also leads to higher complexity in acquisition and tracking.Based on the GNSS L1 civil signals' characteristics of long code cycles and their structures of dual channels of pilots and data,this thesis studies the key technologies of acquisition and tracking of software receivers and brings out with feasible solutions for receiving GNSS L1 civil signals with software.The main achievements of the dissertation are as follow:As Beidou B1 C,GPS L1 C and Galileo E1 OS have long code periods,this paper adopted the fast acquisition algorithm of sparse Fourier transform(SFT)and CIC filtering.After comparing and analyzing the detection probability and computational cost of the two methods and using the measured data to verify the results,the study gets several conclusions: although the SFT method can effectively reduce the computational complexity,the algorithm has negative effects on the acquisition peak-to-peak ratio deteriorates and decreases the acquisition performance seriously;CIC fast acquisition can effectively reduce the computational complexity without affecting the acquisition peak-to-peak ratio,as a result,CIC is an ideal fast acquisition method which is suitable for the cases in which resources are relatively insufficient but fast acquisition are required.As Beidou B1 C,GPS L1 C,and Galileo E1 OS signals have dual-channel structures of pilot and data,this paper uses joint acquisition and joint tracking methods to optimize the receiving performance.Firstly,by analyzing the detection probability and computational complexity of joint acquisition and verifying the results with real data,the study finds that joint acquisition can effectively improve the acquisition sensitivity.Secondly,the study compares the data branch single-component tracking,the data component tracked by the phase auxiliary of pilot component,and the data component tracked by joint tracking,and analyzes the standard deviations of the data tributary carrier phase obtained by the three tracking methods.The results show that joint tracking has the best performance.Joint acquisition and joint tracking are suitable for the cases in which signals are weak but require high sensitivity of acquisition and tracking.Based on the characteristics of the GNSS L1 civil signals,the study receives QMBOC and TMBOC signals with MBOC(matching)and BOC(1,1)(non-matching)methods respectively and compares the performance of the two received modes.The results show that the performance of the two receiving methods of TMBOC is similar,but the matching receiving performance of QMBOC is better.In terms of tracking sensitivity,the two tracking methods of QMBOC and TMBOC have similar performance.The non-match reception of TMBOC and QMBOC has the same ranging accuracy.This has important theoretical significance for the development of low-end multimode civilian receivers.