Digital Magnetic Compass and Gyroscope Integration for Pedestrian Navigation

When satellite signals are available, the localisation of a pedestrian is fairly straightforward. However, in cities or indoors, dead reckoning systems are necessary. Our current research focuses on the development of algorithms for pedestrian navigation in both post-processing and real-time modes. Experience shows that the main source of error in position comes from the errors in the determination of the azimuth of walk. By coupling a magnetic compass with a low-cost gyroscope in a decentralized Kalman filter configuration, the advantage of one device can compensate the drawback of the other. If we compare the rate of change of both signals while measuring the strength of the magnetic field, it is possible to detect and compensate magnetic disturbances. In the absence of such disturbances, the continuous measurement of the azimuth allows to estimate and compensate the bias and the scale factor of the gyroscope. The reliability of indoor and outdoor navigation improves significantly thanks to the redundancy in the information. Numerous tests conducted with different subjects and in various environments validate this approach.