Investigation of a fluxgate sensor for detection of magnetic anomalies

Abstract

Abstract

This paper presents the results of research on fluxgate sensors, which are widely used in underwater navigation systems, magnetic anomaly detection, seabed magnetic surveying, as well as in tasks related to the detection of sunken objects and exploration of underwater mineral deposits. The relevance of this work is driven by the requirements for high speed, energy efficiency, and accuracy of equipment operating under complex hydrological conditions. Within the framework of this study, a mathematical model describing the formation of the output signal of a fluxgate sensor under unipolar pulsed excitation was examined under field conditions. The relationship between the time to reach the maximum output signal and the magnitude of the excitation signal was established using fluxgate sensor samples with cores made of the amorphous alloy AMAG-170. The experimental procedure included recording sensor output signals with a digital oscilloscope while varying the amplitude of the unipolar excitation pulse within the range of 4–14 V at a fixed pulse duration of 1 µs. The practical significance of the obtained results lies in the potential for optimizing the operating modes of fluxgate sensors. By knowing the predicted time to reach the maximum output signal for a given excitation amplitude, it becomes possible to synchronize the sensor polling instant with the peak of the useful signal. This approach enables high-speed operation of fluxgate sensors through the use of unipolar pulsed excitation, exclusion of non-informative signal components (reverse overshoot, noise) from processing, reduction of computational load on signal processing systems, and, consequently, a decrease in the critically important power consumption of autonomous underwater vehicles.