Research On Acquisition Performance And Parameters Optimization Of MC-BOC Signals

In order to realize the separation of military and civilian signals,improve the positioning accuracy and adapt to the lack of spectrum resources,a lot of new navigation signals have emerged.Among them,the MC-BOC signal has great research value based on its good constant envelope characteristic and high spectrum utilization rate.In order to make better use of MC-BOC signal,this paper will focus on MC-BOC signal acquisition performance and parameter optimization.The conventional optimization methods don't consider the influence of the non-ideal front-end,but also has little research on the optimization of the frequency and code phase search interval in the acquisition process.For the new navigation signal,there is no better general method.Therefore,this paper will learn from the BPSK acquisition algorithm to study the MC-BOC signal acquisition performance and parameter optimization problems.The main contents are as follows:?1?Through the analysis of MC-BOC signal power spectrum and autocorrelation function,it can be acquired as a special BPSK signal.Firstly,the acquisition performance and output signal-to-noise ratio are analyzed for three common acquisition algorithms.And then the Monte Carlo simulation results show that the MC-BOC acquisition performance is in good agreement with the simulation results.Finally,the coherent integration time and the post-accumulation times are optimized using the equivalent loss and output signal-to-noise ratio.The results show that the optimal value of coherent integration time is inversely proportional to the Doppler frequency in the matched filter algorithm.With the increase of the carrier to noise ratio,the optimal value of the coherent integration time and post-accumulation frequency is decreasing,but the optimal coherent integration time is not change on the whole.?2?As for the effect of quantization error and limited bandwidth on MC-BOC acquisition performance,Firstly,the effect of quantization error on the SNR of the output signal is analyzed,and the quantization gain is optimized by the output SNR.It is concluded that the optimal value of the quantization gain based on the acquisition is the same as the one optimized directly by the quantization loss.Then,this paper has analyzed the influence of the limited bandwidth on the output SNR.Finally,the non-ideal front-end is used to optimize the coherence integration time and the post-accumulation times in the acquisition signal-to-noise ratio.Compared with the ideal front-end optimization result,the optimal value of the integration time increases slightly,and the optimal post-accumulation times increases obviously.It indicates that the loss of the output signal-to-noise ratio caused by the non-ideal front-end has little effect on the coherent integration,but requires a longer integration time to achieve a certain acquisition performance.?3?For the problem that traditional search acquisition interval is no longer applicable to the new navigation signal,this paper proposes an optimal frequency and code phase search interval method based on equivalent ideal detection factor of unit complexity.Firstly,the optimization formula of frequency and code phase search interval of MC-BOC signal is derived from matched filter,extended to the parallel frequency search and the code phase search algorithm.The optimal design has combined acquisition performance with complexity.Then,the effect of the non-ideal front-end on the frequency and code phase search optimization interval is analyzed.,And finally compared with the existing single optimized frequency and code phase search interval method,it is proved that this method optimizes the acquisition performance corresponding to the single optimization result.After optimizing the search interval under different carrier-to-noise ratio,coherent integration time and non-ideal front-end,it is concluded that the optimization of the code phase interval is closely related to the autocorrelation function.And the frequency search optimization interval is inversely proportional to the coherent integration time.The C/N₀ and the non-ideal front-end have less influence on the optimization results.After taking into account,code phase optimization interval is 1/8 chips,frequency search optimization interval is 1/?2Tc?in MC-BOC signal acquisition algorithm.