多普勒频移修正在测定直升机飞行噪声固有频率中的应用

Determination of the natural frequencies in helicopter noise by Doppler frequency shifts superposition

对于噪声信号采集系统采集的某型直升机的飞行噪声信号,提出了结合机载GPS数据,进行多普勒频移修正,然后叠加多个多普勒频移修正结果,以得到直升机旋翼、尾桨和减速器噪声固有频率的新方法,可以大大减小单次多普勒频移修正的误差。这种方法为确定飞行器飞行噪声固有频率提供了有效的途径。

A new method for the determination of the helicopter noise natural frequencies, which is based on the superposition of results of Doppler frequency shift measurement, is presented in this paper. In order to measure the Doppler frequency shifts, the flight paths are recorded by GPS instrument on the helicopter. The superposition can greatly decrease the error of offering just single Doppler frequency shift. The results show that this method is efficient for determining the natural frequencies of the aircraft flight noise.