小波分析在惯性—多普勒声呐组合导航系统中的应用研究

Research on the integrated INS/Doppler navigation system based on wavelet transform

在惯性—多普勒声呐组合导航系统中,多普勒声呐为惯性导航系统提供舰船的外部速度信息。组合导航系统的速度误差主要取决于多普勒声呐测速误差,多普勒声呐的性能将决定惯性导航系统的精度。由于舰船的摇摆、风浪、海水温度、多普勒声呐本身的缺陷等因素,使多普勒信号中不可避免地受到其噪声的影响。针对多普勒声呐信号的特点,采用小波变换对声呐信号进行多分辨力分析。利用Daubechies小波函数,采用阈值去噪的方法,能够在低信噪比的情况下准确地估计多普勒声呐的频移,从含有噪声的多普勒信号提取出原始信号。通过仿真实验表明,将小波分析应用于惯性—多普勒声呐速度组合导航系统中,能有效提高导航系统的速度精度。

In the integrated INS/Doppler navigation system, the Doppler sonar senses the velocity of the ship, and provides to the INS. The performance of the Doppler sonar will affect the precision of INS, and the velocity error of the integrated system is mainly defined by the measure error of the sonar. In practice there are some factors, such as the movement of the ship, the ocean wave, the temperature of the water, and the fault of the Doppler sonar itself,disturb the measure result. To improve the definition of Doppler sonar, a multi-resolution analyses method is presented to deal with the signal in view of the characteristics of the Doppler sonar. By using threshold decreasing noise,detailed analyses are demonstrated that Doppler sonar＇s frequency excursion can be estimated precisely with Daubechies wavelet function. The simulation results show that the velocity of integrated INS/Doppler navigation system can be improved by applied the wavelet analysis.