α-β-γ滤波器在GPS多普勒频移测量中的应用

The Application of α-β-γ Filter to GPS Receiver's Doppler Measurement

目前,许多GPS接收机中多普勒频移的测量都由载波积分多普勒对时间求导获得,积分时间在降低测量噪声与实时性之间存在矛盾。α-β-γ滤波器的应用有效地解决了这一矛盾,选取较短的积分时间以减小积分多普勒反映的平均速度与用户机在观测量提取时刻的瞬时速度差异,同时加入α-β-γ滤波器降低多普勒频移的测量噪声。本文详细论述了α-β-γ滤波器在多普勒频移测量中的工程实现,并进行了仿真试验。

In many modern GPS receivers, the Doppler frequency shift of the carrier is derived from derivative of integrated carrier Doppler phase measurements. However, there is a contradiction about the integration time between reducing measurement noise and getting the real-time measurement. The α-β-γ filter resolves this contradiction effectively. The shorter integration time is selected to reduce the difference between the aver- age velocity reflected by integrated carrier Doppler phase measurements and the instant velocity at the measure time, while theα-β-γfilter is applied to reduce the measurement noise. The implementation of α-β-γ filter applied in measurement of carrier Doppler is discussed, and the simulation results are showed as well.