Optimization Analysis of Pseudo - Code Signal Acquisition Interval in Non - ideal Front - end Condition
Xin Zhao Xinming Huang Xiangwei Zhu Guangfu Sun, National University of Defense Technology, Cnina
The satellite navigation receivers widely used are mainly digital receivers. In the process of signal processing, it is necessary to consider non-ideal front-end problems - limited bandwidth and front-end quantization error. The general satellite navigation digital receiver uses 1-bit or 2-bit quantization, resulting in quantization noise compared to analog signals, and loss of signal-to-noise ratio for subsequent acquisition modules. Moreover, the research on the front-end quantization is the loss of signal-to-noise ratio of the front-end signal, and the influence of the acquisition part is not well studied. The limited bandwidth also causes the matched filter loss after the signal enters the acquisition module, which affects the acquisition performance of the signal. In order to optimize the acquisition interval of the pseudo-code signal, it is necessary to consider the influence of the non-ideal front-end, so as to provide guidance for the actual receiver implementation.
In this paper, we mainly use the equivalent ideal detection factor of unit complexity (Du) to optimize the acquisition interval. By analyzing the influence of the non-ideal front-end condition, the expression of Du is extended to optimize the acquisition interval of the pseudo-code signal analysis. By analyzing the influence of finite bandwidth and front-end quantization error on the signal-to-noise ratio, the interval optimization of pseudo-code signal in different finite bandwidth and front-end quantization error are numerically calculated, and the change trend is analyzed and the variation rule is summarized. Compared with the results of the ideal front-end optimization, we can see that the quantization error and the finite bandwidth of the non-ideal front end have little effect on the frequency optimal search interval and the code phase optimal search interval. The optimization value of the frequency search interval is slightly increased with the quantization bit number. And the finite bandwidth is almost no effect on the frequency search interval. With the increase of the finite bandwidth, the code phase optimized is stable near the ideal value.