Design Of Digital Electronic Compass System Based On MEMS Sensors

The electronic compass, as an important navigation equipment providing real time heading and attitude information based on the local earth magnetic field, has been widely used in the fields of aviation, marine and vehicle navigation and mobile phone positioning system. Electronic compass based on MEMS technology has been playing a more and more important role in military and civil field due to its low price, small size, light weight and high integration features.After a full study of the magnetic heading system’s development course, its current development direction at home and abroad and a detailed explanation of heading measurement and tile compensation principle, this paper presents the design and implementation of an electronic compass system based on STM32F103MCU and system-in-package LSM303DLHC featuring a trial-axial acceleration sensor and a tri-axial magnetic sensor. In this system architecture, MCU reads the output of the three-axial magnetic sensor and three-axial acceleration sensor through HC serial communication buses, and then use the error compensated model which is built according to the analysis of the major error sources of electronic compass system to compensate the sensor’s output. The compensated sensor outputs are then used to calculate the heading and attitude information. MCU transmits the heading and attitude result to PC through RS232serial interface for real time3d showcase. This system architecture minimizes the use of unnecessary peripherals to maintain its simplistic structure, small volume and low power consumption.The experiment results show that the designed compass system can dynamically measure the pitch, roll and heading angle with a heading precision of±1°during0-360°range. The designed electronic compass with its low weight, power consumption and low price features, can be used in vehicle orientation and common navigation field after further improvement.