A Ship Monitoring Magnetic Field Sensor

Abstract

The invention relates to a novel ship monitoring magnetic field sensor based on the ultrasonic sensing and magnetic detection technology. The sensor comprises a silicon substrate, a metal electrode, an insulating layer, a piezoelectric film, and a cavity filled with low concentration magnetic fluid. The sensor is characterized in that the sensor can emit or receive an ultrasonic wave, the viscosity of the magnetic fluid in the cavity is very sensitive to an external magnetic field, in the condition of no magnetic abnormal source, the sensor carries out ultrasonic detection in a mode of an underwater acoustic transducer, when a magnetic abnormal source appears, the sensor can carry out ultrasonic detection and magnetic detection at the same time, and the ultrasonic frequency emitted by the sensor can be controlled by applying a bias magnetic field. The ship monitoring magnetic field sensor is manufactured by using the advanced micro nano processing technology, the volume is small, the power consumption is low, the frequency band is wide, a one-dimensional line array (1D) and a two-dimensional surface array (2D) can be made, the sensor is compatible with a front-end electronic circuit, the mass production of devices is facilitated, and the sensor is suitable for coastal defense, anti submarine, warship detection, ocean topography detection and the like.

Description

technical field [0001] The patent of the present invention relates to the technical fields of ultrasonic sensing and magnetic detection, in particular to a ship monitoring magnetic field sensor, which is mainly used in coastal defense, anti-submarine and ship detection. Background technique [0002] The detection of large targets in water (submarines, nuclear submarines, hidden reefs, etc.) can be achieved by means of sonar, radar, laser, and magnetic detection. Among them, sonar technology is the earliest underwater detection technology, which is widely used in all aspects of naval underwater activities and is the main means of submarine detection, reconnaissance and navigation. As an important part of the sonar system, the underwater acoustic transducer is a device that converts electric energy and acoustic energy. Its principle is to use the propagation characteristics of sound waves in water to realize electroacoustic energy conversion through piezoelectric materials or ...

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Problems solved by technology

[0006] (2) The proton precession magnetometer is developed based on the principle of magnetic resonance by using the precession phenomenon of protons in the geomagnetic field. Its advantages are high precision, generally in the range of 0.1-10nT, good stability, and high working speed. Fast, can directly read the nT value of the geomagnetic field. The disadvantage is that the polarization power is high, and it can only be used for fast point measurement, and it is greatly affected by the magnetic field gradient.

[0007] (3) The optical pump magnetometer is a magnetometer made according to the atomic transition principle in the nucleus. It has high sensitivity, can reach 0.001nT, no zero drift, no orientation, no strict requirements on the surrounding magnetic field gradient and continuous observation advantages, but its structure is relatively complex, and high-precision frequency measurement is required for detection

[0008] (4) The Superconducting Quantum Interference Magnetometer (SQUID) is manufactured according to the principle of superconductivity. It is the most sensitive instrument for measuring magnetic field so far, with a sensitivity of up to 10 -5 ~10 -6 nT, but the process of manufacturing superconducting Josephson junction is relatively difficult, and low-temperature refrigeration equipment is required, the technology is complex and expensive

[0009] (5) The full tensor magnetic gradient measurement system is mostly developed based on SQUID, and its measurement object is the gradient of the magnetic field vector component, which is not limited by the total field measurement, and the measured results can reflect the vector magnetic moment information of the target body , since the tensor elements are less affected by the inclination and declination of the geomagnetic field, the tensor invariants calculated from them do not require additional processing, and the magnetic gradient tensor inversion can well describe the magnetization direction and geometry of the magnetic field source form, but the system has complex structure, high technical requirements, large volume and high cost

[0011] To sum up, the current sonar systems or magnetometers used for coastal submarine detection have not been able to solve the problems of rapid detection accuracy, volume, power consumption, cost, mass production, etc., and these traditional devices Either through ultrasonic detection, or through magnetic detection, there is no research to combine the two or combine the two organically and complementary

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