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为避免采样频率偏差给卫星导航接收机带来的符号位滑动、伪随机噪声码相位移动和载波相位偏差等问题,提出了一种改进的频率偏差估计方法.接收机的码跟踪环路以码速作为时间基准,对采样频率实际值与标称值之间的偏差进行跟踪,环路稳定后得到该偏差的估计值,其采样频率的准确度可提高到10-7量级.将该估计值补偿到载波锁相环中,可减小由采样频率偏差带来的相位误差和多普勒频移偏差,从而使得导航接收机能正确解调信号,进一步提高了输出载波相位的准确度,为实现更高精度的定时和定位提供了可能性.
In order to avoid the problems such as sign bit sliding, phase shift of pseudorandom noise code and carrier phase deviation caused by sampling frequency deviation to satellite navigation receivers, an improved frequency deviation estimation method is proposed. The receiver’s code tracking loop uses a code Speed as a time base to track the deviation between the actual value and the nominal value of the sampling frequency, the estimated value of the deviation obtained after the loop is stable, the sampling frequency accuracy can be increased to 10-7 order of magnitude The estimate Value compensation to the carrier phase locked loop, the phase error and Doppler shift deviation caused by the sampling frequency deviation can be reduced, so that the navigation receiver can correctly demodulate the signal to further improve the accuracy of the output carrier phase, which is It offers the possibility to achieve more accurate timing and positioning.