Vector OBF detection method of magnetic tensor for small magnetic targets

To improve the detection probability of small magnetic targets and enrich the direction information in magnetic scalar orthonormal basis function (OBF) detection, this paper proposes a vector OBF detection method using the magnetic tensor. Firstly, the OBF expression of the magnetic tensor is determined by analyzing the OBF decomposition principle of the magnetic tensor vector. Then, the magnetic tensor vector OBF detection model is constructed, and the magnetic tensor vector OBF detection method is proposed. Finally, the AR whitening filter is investigated to optimize the proposed method. The detection method can detect small magnetic targets under the condition of a low signal-to-noise ratio (SNR). The simulation results indicate that the detection accuracy of the scalar OBF detection method is significantly decreased under the Gaussian noise with an SNR of −19 dB, while the vector OBF detection method can still effectively detect magnetic anomaly signals; when detecting the same target under the false alarm probability of 1.5% and different fractal noises, the detection probability of the vector OBF detection method is 6 ~ 35% higher than that of the scalar OBF detection method.