The Signal Of The Terrestrial Magnetism Gathers And Process System Based On PCI Bus

The measurement of magnetic signal is the prime technology when we study the physical phenomenon that is related to magnetism. Fluxgate is a tool to measure the magnetic signal, in the past it was applied only in some specific field. Of late years, with the popularization and infiltration of automation, measurement and electronic technology, and the change of modern technology with each passing day, fluxgate is used in many new fields.With the application of fluxgate in naval vessel's locating as the background, this paper make a research in the phenomenon, working principle and characteristic of fluxgate, and the design of the system of collecting and processing the fluxgate signal. The latter is the emphasis of our paper.The core intellectual device of the collecting system is the DSP chip. DSP can not only supervise and control the system, but also expand some function, such as digital filter, data encapsulate, etc. On the local bus, with a series of analog circuits, the signal has such disposal: amplification, filter and demodulator, and through the AD the signal is converted to data and is stored in DSP. After some simple disposal, the data is transmitted to host through PCI in order to have some further position operation. PCI is a kind of bus with some outstanding performance, but it can't be used directly. So we use the bridge chip to convert the PCI bus to standard local bus. The hardware needs the cooperation of software to work normally, so we design the driver program for the PCI demodulator. In the end we have to design the application program to demonstrate the specific position of the naval vessel. Our system can collect the fluxgate's signal correctly, calculate the specificposition of the naval vessel, and increase the dependability and security of the naval vessel's sails.