The Design And Implementation Of Three-Component Geomagnetic Field Detection System

With the application fields of geomagnetic field detection enlarging increasingly, the kinds of magnetic survey instruments are richer. Compared with other magnetic survey instruments, the ones based on three-component fluxgate sensor possess advantages of high precision and sensitivity, wide measurement range in low-intensity magnetic field, small volume, light weight and low power consumption, and have been applied in military weapon, medical inspection, national defense construction, daily life and many other fields. With the requirement of magnetic measurement improving continually, the synchronous measurement of geomagnetic field on three vertical directions has been the emphasis of research.A geomagnetic field detection system based on three-component fluxgate sensor is designed according to this paper. The operating principle of fluxgate sensor is analyzed firstly, and it's structural style is determined. Then a detailed introduction of method of quadratic harmonic is presented and a overall designing scheme of the detection system is put forward. In this scheme, detection system includes slave computer design and upper computer design.The slave computer uses DSP of TMS320F2812 as main controlling chip, which completes tasks of controlling ADS 1278 and collecting datum. The slave computer contains hardware design and software design. Hardware circuits consist three same fluxgate signal disposing circuits based on method of quadratic harmonic, horizon sensor circuit of SCA100T-D02, single-ended to differential circuit, ADS 1278 chip with peripheral circuit and DSP controlling circuit. Software design includes the design of ADS 1278 configuration, SPI module of acquiring signal and serial port communication of 485. Analog-to-digital converter of ADS 1278 of 24-bit and 8 channels realizes synchronous measurement of 5 channels. Upper computer software is compiled by LabVIEW, and accomplishes functions of controlling slave computer, reading datum collected by slave computer, digital-to-analog converting and displaying the final results.In the end, function modules test and system performance test are finished, and system performance test includes degree of nonlinearity and consistency tests. The results show that the three-component geomagnetic field detection system presented in this paper meets all the index requirements.