| In recent years,the rise of China’s BeiDou Navigation Satellite System(BDS)has become the successor to the US Global Position System(GPS)and Russia’s Global Navigation Satellite System(GLONASS).The third largest mature satellite navigation system.With the rapid development of the Global Navigation Satellite System(GNSS),the once popular BPSK modulation method also faces great challenges.In addition to poor anti-interference ability and susceptibility to multipath effects,a series of disadvantages and defects such as spectrum utilization and compatibility are gradually revealed.In August 2017,China released the B1C signal ICD file on the Beidou official website.The document indicates that the BDS3-B1C signal uses BOC modulation and QMBOC modulation.The proposal of BOC modulation has alleviated the problem of frequency band congestion,creating a precedent for spectrum sharing.Due to the complexity of the electromagnetic environment,GNSS receivers are extremely susceptible to interference during reception,demodulation,and positioning,and sometimes even fail to work properly.Under certain interference,it is an important branch of the satellite navigation field to explore the anti-jamming performance of GNSS navigation signals and propose effective evaluation methods.Based on the system characteristics of BDS3-B1C signal,this paper takes the qualitative analysis of the GNSS receiver correlation filter output power spectral density change and the quantitative analysis of the bit error rate,respectively for continuous wave,band-limited Gaussian white noise and BPSK.Interference efficiency simulation analysis of interference patterns.From the theoretical simulation and hardware design to verify the feasibility of this test technology,the main work of this paper is as follows:1.For BOC and QMBOC modulation,according to its modulation principle and modulation process,its spectrum performance and autocorrelation function are analyzed,and the modulation order of the BOC modulation signal and the main lobe bandwidth,the total number of main side lobes,and the total number of correlation peaks are derived And the performance of QMBOC modulated signal tends to BOC(1,1)and verify its conjecture.2.Based on BOC and QMBOC modulation,the interference effects of continuous wave,band-limited Gaussian white noise and BPSK on BOC(1,1)and QMBOC(6,1,4/33)were analyzed.In conclusion,the relationship between the power of the interference signal and the interference performance under the same modulation and the interference effects of different interference patterns under the same interference power are given.Based on the actual situation,suggestions for different interference patterns are given.3.Based on the BOC and QMBOC modulation theory,from the perspective of the hardware implementation of the interference test equipment,it is divided into 5 parts for modular design.The specific functions and circuit implementation of each module are elaborated in detail.In-depth study of the algorithm design and hardware implementation of the three kinds of interference signals mentioned above.Finally,based on the DSP+FPGA platform,the interference signal designed by the spectrometer was observed to meet the previous requirements,which further proved that the interference assessment scheme proposed in the paper was feasible. |
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