基于双相关峰检测的C/A码伪距精密估计

Precisely Evaluating Pseudo-Range of C/A Code Based on the Method of Two Correlation Peaks Detection

采用软件无线电技术和数字信号处理技术,直接对A/D变换后的中频信号进行处理,并得到C/A码的相关曲线。利用曲线拟合方法对相关峰波形进行拟合,进一步确定相关曲线的峰值点位置。同时基于双相关峰检测的伪距估计方法,精确求解C/A码伪距观测值。利用自编的仿真程序包,在Matlab中进行了相应的模拟计算。仿真结果表明当信噪比大于26dB时,可得到毫米数量级的伪距估计精度,能够满足GPS模拟源系统高精度自校的要求。

The intermediate frequency signal, which had been converted from analog to digital, was directly processed in DSP by using the software radio technique. The correlation curve of C/A code was obtained. The waveform of correlation peak was fitted using a curve fitting method, and then the peaks of correlation curve were located precisely. At the same time, the pseudo-range of C/A code was evaluating precisely based on the method of two correlation peaks detection. The corresponding computation was accomplished using the self-prograimning emulating package with the help of Matlab. The simulation results indicate that the evaluating precision of pseudo-range obtained is close to millimeter level when signal-to-noise ratio is better than 26dB, which can meet needs of self- revising module in GPS simulating system.