The Design Of Attitude Measurement System Based On Magnetoresistive Sensor

Heading and attitude are the most important parameters in the navigation and locating system.In this paper,on the base of analysis at home and abroad magnetic sensors,which use magnetoresistive sensor and accelerator to compose the attitude measurement unit.and use C8051F020 as the core of the hardware platform to collect experiment data and to realize the attitude algorithm.Firstly the basic theories and operational principles of attitude measure system are introduced,including the earth's magnetic field module,the selection of the magnetoresistive sesors and accelerator and attitude matrix building .Secondly I focus on the hardware and software design of attitude measure system based on C8051F020.In the hardware design,we present the overall plan of hardware design and discuss power source circuit,signal conditioning,set/reset circuit,LCD display , UART0 circuit and E~2PROM memory function module in detail.At last,display the heading on the LCD and though the UART0 transmit the data to the PC.Software is developed accoding to the attitude measure algorithm,manily including initial of the resource on the chip ,data collection and calculation of the attitude angle.PC software written by VB realizes data collection and interface display.Lastly I analyze the reasons of magnetic heading error including A/D convert resolution,iron material, magnetoresistive sensor error and tilt error.Then especially analyze the magnetic distortions which are categorized into hard iron and soft iron effects.then supply two compensation methods.