基于双相关峰检测的C/A码伪距精密估计

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。

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

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.