GPS L1C信号的仿真分析

GPS L1C信号采用数据和导频双通道结构.基于Matlab仿真产生L1C信号并分析了数据、导频通道的自相关和频谱特性,两通道有类似的相关函数包络,导频通道自相关函数的旁峰相比数据通道向外偏移0.06个码片,相同的码相位范围内峰值变化更加剧烈,其相关峰的斜率比数据通道自相关函数高2.56dB,中心主峰更窄.比较了不同前端带宽下BPSK(1),BOC(1,1),BOC(6,1),TMBOC(6,1,4/33)调制信号的均方根带宽,理论上TMBOC(6,1,4/33)信号的跟踪精度相比L1C/A信号提高了57%.分析了次级码的相关特性.它具有强自相关性,有效降低卫星信号互相关函数的旁瓣,旁瓣比为27.4dB.研究表明L1C信号具有优良的跟踪精度和减少互相关干扰的潜能.

Simulation Analysis of GPS L1C Signals

GPS L1Csignal adopts data and pilot channel.Firstly based on Matlab software,we simulate L1Csignal and analyse the autocorrelation and spectral characteristic of data and pilot channel,this two channel have similar correlation function envelope,the pilot channel autocorrelation's side-peak offset outward 0.06chip.It is found that the peak value changes more intense in the same code phase range,the autocorrelation's slope is 2.56dB higher than the data channel's,The center main peak is more narrow.Then we compare RMS bandwidth of BPSK(1)、BOC(1,1)、BOC(6,1)and TMBOC(6,1,4/33)signal under different front-end bandwidth,the tracking accuracy of TMBOC(6,1,4/33)signal is increased by 57%than L1C/A signal in theory.Finally we analyse the correlated characteristic of Secondary code,it reduce the satellite signal's sidelobe of cross-correlation function effectively,the sidelobe ratio is 27.4dB.It is shown that L1Csignal has the potential in tracking accuracy and reducing the cross-correlation interference.