Research On The Improvement Of Accuracy Of GNSS Course Based On Electronic Compass

With the development of science and technology, every country attaches great importance to navigation and positioning technology as a form of the national economic and scientific research capacity. GNSS(Global Navigation Satellite System) is widely used in navigation, positioning, timing, speed and orientation. But the course angle of GNSS is determined by simple calculation of two points, rather than the position information obtained through accurate parameter measurement. So the precision of the course angle is not high, generally more than 1°, particularly worse in the case of low speeds or stillness. This paper designed a electronic compass with low power and small, and it can effectively compensate the precision of the course angle. Thereby the accuracy of course angle can be improved availably.Design and exploitation of the hardware of electronic compass include the controller module, the GPS module, the accelerometer and magnetometer sensor module and the gyroscope module. The controller module collects GPS statements from the GPS module and parses out the longitude and latitude, declination and other information. The controller module reads the original data from the sensors through the IIC interface, and calculates attitude angle.Design and exploitation of the software of electronic compass consist of the system initialization module, the calibration magnetometer module, the IIC communication module and the data calculation module. The system clock and interrupt settings will be configured in the system initialization module. The magnetometer calibration module derives correction of magnetometer data through the method of fitting ellipsoid. Reading data of sensors is finished in the IIC communication module, and prepares for the calculation of attitude angle. The rotation matrix is derived from the measurement of magnetometer and accelerometer data in data calculation module, and then derive the course angle from the rotation matrix.The test results show that the precision of the course angle of electronic compass can get to 0.49°, and can improve the accuracy of the course angle of GNSS effectively.