Position determination device and method

A position determination method comprising:

• obtaining at least one magnetic field vector sensed by a magnetic sensor;
• determining the magnetic magnitude and a further magnetic parameter of the at least one obtained magnetic field vector;
• comparing the determined magnetic magnitude with a predetermined magnetic magnitude map of a region around the magnetic sensor to obtain a first estimate of the sensor position;
• comparing the determined further magnetic parameter with a corresponding predetermined further parameter map of a region around the magnetic sensor to obtain a second estimate of the sensor position;
• determining weight information indicating the reliability of the first and/or second estimate of the sensor position and/or the relative weight of the first estimate with respect to the second estimate, wherein the weight information is determined based on a local variation of one or more of the magnetic magnitude in the magnetic magnitude map in a local sensor area, wherein the weight of the first estimate is decreased corresponding to less variation in the magnetic magnitude in the local sensor area, and the further magnetic parameter in the further parameter map in the local sensor area;
• weighting the first and second estimates of the sensor position according to the determined weight information;
• and
• determining the sensor position from the weighted first and second estimates,
• wherein a radius range of the local sensor area is adjusted dynamically based on the local variation of one or more of the magnetic magnitude map and the further magnetic parameter map, wherein the radius range is increased corresponding to more variation in the local sensor area.

A non-transitory computer-readable recording medium that stores therein a computer program product, which, when executed by a processor, causes the processor to perform a method, the method comprising:

• obtaining at least one magnetic field vector sensed by a magnetic sensor;
• determining the magnetic magnitude and a further magnetic parameter of the at least one obtained magnetic field vector;
• comparing the determined magnetic magnitude with a predetermined magnetic magnitude map of a region around the magnetic sensor to obtain a first estimate of the sensor position;
• comparing the determined further magnetic parameter with a corresponding predetermined further parameter map of a region around the magnetic sensor to obtain a second estimate of the sensor position;
• determining weight information indicating the reliability of the first and/or second estimate of the sensor position and/or the relative weight of the first estimate with respect to the second estimate, wherein the weight information is determined based on a local variation of one or more of the magnetic magnitude in the magnetic magnitude map in a local sensor area, wherein the weight of the first estimate is decreased corresponding to less variation in the magnetic magnitude in the local sensor area, and the further magnetic parameter in the further parameter map in the local sensor area;
• weighting the first and second estimates of the sensor position according to the determined weight information;
• and
• determining the sensor position from the weighted first and second estimates,
• wherein a radius range of the local sensor area is adjusted dynamically based on the local variation of one or more of the magnetic magnitude map and the further magnetic parameter map, wherein the radius range is increased corresponding to more variation in the local sensor area.