磁异信号自适应检测算法

Adaptive Detecting Algorithm for Magnetic Anomaly Signal

针对在分形噪声1/fα(0≤α<2)中检测磁异信号存在的问题,提出了一种自适应噪声抵消器与自适应AR白化滤波器相结合的磁异信号正交基函数(OBF)检测算法——改进的OBF检测算法。由于固定AR白化滤波器对分形噪声1/fα的白化效果不佳,影响了OBF检测算法的性能,因此采用自适应噪声抵消器对被检测信号进行预处理以提高其信噪比,再利用自适应AR白化滤波器对预处理信号进行白化滤波,以实现OBF检测算法的最优化。理论仿真结果表明:当α值接近于0时,改进的OBF检测算法的处理增益略高于未经白化的OBF检测算法;当α值接近于2时,改进的OBF检测算法的处理增益略高于基于AR白化滤波器的OBF检测算法;当α值约等于0.8时,改进的OBF检测算法的处理增益高于其他两种算法7 dB,实验结果表明改进的OBF检测算法可以检测更微弱的磁异信号。

As for the poor effect of correlation detection algorithm based on orthonormal basis functions（ OBF） with AR whitening filter in pink noise 1/fα（0 ≤α〈t;2）,a new OBF detection algorithm was proposed,which is using an adaptive AR whitening filter combined with an adaptive noise canceller. Firstly, an adaptive noise canceller was designed to improve the input SNR of the magnetic anomaly signal. Secondly,the de-noised signal was whitened by the adaptive AR whitening filter. Finally,the whitened signal was passed through matched filters based on OBFs of the detected magnetic anomaly signal. The improved algorithm was verified by the simulation data and actual measured data. The simulation results show that when αis close to zero,the improved algorithm has advantage over OBF detection algorithm without whitening filter. And the improved algorithm is better than OBF detection algorithm based on AR whitening filter,whenαapproaches to 2. Especially,whenαis approximately equal to 0. 8,the output SNR of the improved algorithm is 7 dB higher than the other two algorithms mentioned above. The experiment results show that the improved algorithm increases the detection ability of weak magnetic anomaly signal in pink noise.