Design And Research On Errors Compensation Of The Reluctance Digital Compass Based On SOPC

Digital compass have been used in the fields of vehicle orientation, ship navigation, unmanned aerial vehicle, and mobile phone and so on as a kind of detection system, which can provide the real-time heading and vehicle attitude. This article designs magnetoresistive digital compass based on SOPC from the geomagnetic navigation.The paper stadys the magnetic heading system and the development course fully at home and abroad and analysises the principles of geomagnetic field. This article designs a low power digital compass based on the AMR sensors and accelerometers according to these researchs.Several measurement methods are given and advantages and disadvantages are analysised in this paper. Magnetoresistive measurement methods are selected finally. According to the design indexes of the system, the magnetoresistive sensor, HMC1021 and HMC1022, which is produced by Honeywell Inc, and the dual-Axis Accelerometer, ADXL210, which is produced by Analog Devices Inc, are used in this paper. The paper designs hardware circuits and software flow charts and software programs based on features of output signals of these sensors.The paper shows two kinds of error compensation methods by application on error sources, least square method and ellipse hypothesis and makes a detailed analysis.Through analyzing digital compass prototype, the paper chooses the conventional ellipse hypothesis to compensate errors of the digital compass prototype finally. Many performance tests are made on the digital compass prototype and the tests show that the system designed in this paper meets the demand of design index.In order to debugge the digital compass system conveniently, a debugging tool of host computer is designed based on Visual C++6.0 in the paper. This software tools can receive and show, draw curve of navigation parameters, reveal the changes of Attitude and Azimuth by 3-D Object.