Underwater Weak Magnetic Anomaly Identification Based on Orthonormal Basis Function

Magnetic anomaly detection methods have been employed for decades to detect ferromagnetic targets, however, research on the identification of weak magnetic anomaly targets underwater remains relatively limited. This paper proposes a novel method for identifying underwater weak magnetic anomaly targets using orthonormal basis function decomposition. First, we construct orthonormal basis functions tailored to the characteristics of the target signal. The target signal is then decomposed into the orthonormal basis functions, resulting in a coefficient matrix that facilitates the extraction of target signal energy from raw data with low signal-to-noise ratios (SNR). Subsequently, we invert the target magnetic moment from the coefficient matrix to achieve effective magnetic anomaly identification. Additionally, Brent’s method is utilized to enhance the speed of parameter estimation for the orthonormal basis functions. Experimental results demonstrate that the proposed method outperforms traditional approaches in accurately identifying magnetic anomalies.