Interpretation of signature waveform characteristics for magnetic anomaly detection using tunneling magnetoresistive sensor.

• Wavelet width and sensing range angle are used to characterize the time-varying magnetic signature. • The signature peak strength, magnetometer's sensing range d and angle θ , are all independent of velocity. • The signature waveform width T is used as a cue, which has been found to be inversely proportional to the speed by d = vT. • The sensing range angle θ retains to be nearly θ y = 90° and θ x = 130° for y-axis and x-axis respectively, originating from constant d/CPA factors. A detection procedure by employing the induced magnetic signature characteristics for magnetic targets detection and identification is proposed in this paper. The highly sensitive tunneling magnetoresistive (TMR) sensor with low self-noise is adopted, while the magnetic target is traveling along a straight line at various speed and CPA (closest path approach) for magnetic anomaly detection (MAD). The triple-axis TMR sensor is characterized with a high sensitivity around 100 mV/V/Oe in a linear range of ±1 Oe and a self-noise of 170 pT/√Hz at 1 Hz. The signature waveform width and sensing range angle are used to analyze the signatures. It is found that the sensing range angle is independent of changing velocity and CPA. The proposed signature interpretation strategy is demonstrated by both experimental and simulated data. [ABSTRACT FROM AUTHOR]