Design For Proton Precession Magnetometer Based On MSP430

Proton precession magnetometer is absolute magnetometer that measures the total intensity of the geomagnetic field, which is a kind with higher precision in numerous magnetometers. Even if the magnetic field is weak, such as t the earth's magnetic field, the measurement also can reach higher resolution and precision. Its working principle is in the use of the precession mechanism of hydrogen proton in magnetic field to carry out the measurement. The sensor is full of hydrogenous liquid, the hydrogen protons are in ruleless arranged state before the coercively polarizing by the magnetometer; the protons will turn to direction of external magnetic field when added a polarized signal. The proton precession will work when the polarized signal vanishes. The amplitude of the external magnetic field can be measured through measuring the frequency of the proton precession. Continuously repeat this process, the approximate continuous measurement can be achieved.The measuring precision of the proton precession magnetometer can reach to 0.1 nT, and one measurement can be done in such a few seconds. The device is anti-vibration that can be applied in vehicles such as ship, balloon, airplane, rocket and man-made satellite. If adding a Helmholtz loop to the external of the probe, the device will change to a procession component magnetometer that can measure the component of the geomagnetic field.For its higher precision, reliable performance, cabinet volume and reasonable price, the proton precession magnetometer has been widely used in archaeology, environmental and engineering investigation, the detection of unexploded bomb, landmine and torpedo, also security examine, ferruginous pipeline examine, well logging location, and conventional applications, such as geological investigation, oil-gas and mine exploration et al. According to American Laurel Industrial Company, sixty percent of the global exploration is done by the proton precession magnetometer.Firstly, the paper expatiates the methodology of the proton precession magnetometer and the working principle of the equipment, aslo makes an analysis of the development and design characteristic of the present magnetometer home and abroad; further, gives a total design project of the proton precession magnetometer. The paper fully discusses several important technical designs and their realization: Larmor signal sampling technique, signal amplify and adjustment, and frequency measurement technique. The performance index is tested in the system testing, and detailed analysis of experimental result is given. Finally, makes a conclusion of the paper, also gives some advice of the further research.On the basis of mastering the basic principle of proton procession magnetometer, this paper uses the abundant instrument development experience of Key Laboratory of Geo-exploration Instrument (Jilin University) Minister of Education for reference, the device adopts the low power loss system with low noise amplifier, controlled voltage changeable gain amplifier, switch capacitance filter and CPLD frequency measurement, and the center controller of which is the MSP430F149. Brings forward the entire design project of the proton procession magnetometer, and fully explains the research and design of the key techniques in it. In the concrete circuit design, adequately considers the application environment of the device, and pays attention to the device's characteristic of the portable, low-loss and easy to operate et al.Detailed researches include: The principle of proton procession and the design structure of magnetometer;Design of polarity control and low noise amplified circuit;Design of switch capacitance filter and controlled voltage gain amplifier;Design of Larmor signal adjustment and frequency measurement;Design of controlling system and external functional circuit;Compile the system controlling code;...