ABSOLUTE HEADING SENSOR BLUNDER DETECTION USING RELATIVE HEADING SENSOR AND ROAD SEGMENT
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-May-02
The absolute heading sensor is a very important component of an in-vehicle navigation system. The least expensive one used nowadays is the magnetic compass. However, the problem with this kind of sensor is the sensitivity to magnetic anomalies. Whenever the vehicle is close to a bridge, an over- pass, an elevator track, a steel building or a con- struction site, the compass is affected by the abnor- mal magnetic field. Because of the randomness of these errors, it is very hard to use filters to correct the compass readings. The heading data received from Global Positioning System (GPS) has similar problem. When the satellite constellation is changed, the receiver may have abnormal heading output. In addition, when the GPS receiver is used in urban canyon areas, the multiple path signals may affect the accuracy of the GPS heading. 2. DESCRIPTION This method is based on the assumption that the relative heading sensor is quite accurate in the measurement of the heading variance most of the time. Our field tests demonstrated the correctness of this assumption. The method is based on a set of if-then-else rules to detect blunders and to make corrections.