Magnetic Resistance Type Electronic Compass Application Development And Performance Evaluation

Three-dimensional electronic compass is a navigation tool, the principle is to use the Earth’s magnetic field and the acceleration of gravity to measure the direction. With small size, simple structure, low power consumption, low cost, the electronic compass is widely used in the field of aviation, marine, vehicle positioning, geological exploration, deep sea exploration, The precision reluctance electronic compass has important implications on the improvement navigation and positioning technology and the development of aerospace technology and the cause of national defense.In this paper, the author takes the earth magnetic field and geomagnetic navigation principle as the starting point. The three-dimensional electronic compass is the object of this study. Main research work of this paper is outlined an following:On the one hand, an overview of the principle of the magnetic navigation, Outlined the basis, the internal structure of the3D electronic compass is studyed in this paper, the working principle is parsed.Firstly, the structure of the three-dimensional electronic compass is determined, including attitude angle measurement module and heading measurement module and data processing module.Secondly, the principle of magnetoresistive sensor which is usd for heading measurement is analyzed. This part focuses on the the working principle and the measurement principle of the anisotropic magnetoresistive sensor.Then, the accelerometer sensor which is used for attitude measurement module is introduced, the internal structure of the gravity acceleration sensor is resolved, the detection principle of the gravity acceleration sensor is studyedFinally, the mathematical model for three-dimensional electronic compass application system is established, and the validity of the model is verifyed.On the other hand, the design ideas and implement methods of each functional module in three-dimensional electronic compass application system are mainly explained.Anisotropic magnetoresistive sensor HMC1043which is produced by Honeywell is selected as heading measurement module front-end. The Honeywell HMC1043is a miniature three-axis surface mount sensor array designed for low field magnetic sensing. By adding the HMC1043with supporting signal processing, a cost effective and space-efficient3-axis magnetometer or compassing solution is enabled. Applications for the HMC1043include Compassing, Navigation Systems, Magnetometry, and Current Sensing.Acceleration sensor ADXL203which is produced by ADI is selected as attitude measurement module front-end. The ADXL203is high precision, low power and dual axis accelerometer. it contains a polysilicon surface-micromachined sensor and signal conditioning circuitry to implement an open-loop acceleration measurement architec-ture. The output signals are analog voltages proportional to acceleration. The accelerometer can measure static acceleration forces such as gravity, allowing it to be used as a tilt sensorWith the compass direction and attitude change, the measured values of the magnetoresistive sensor sensitive axis is changed, then the measured values are compensation by the attitude angle measurement module, Finally get the heading angle of the compass.In the last place, all functional modules are integrated, and the system function is perfected. Furthermore, a comprehensive test is complete and the results show that the application system can measure heading angle, and the measurement accuracy meets to the relevant national standards.