Mobile handset with position calculation function
To extend the areas where a mobile handset can determine its position using radio waves, the present invention provides a mobile handset that is equipped with both position calculation means using radio waves from GPS satellites and position calculation means using RF carriers from cellular base stations. Positioning results obtained from both of these position calculation means are combined and weighted with GPS positioning reliability and cellular positioning reliability, respectively. A weighted mean of these results is then output as a final position calculation result.
1. A mobile handset capable of determining its position using radio waves, the mobile handset comprising:
GPS receiver means for receiving GPS-oriented signals and generating received GPS signals;
GPS position calculation means for calculating the mobile handset's position from the received GPS signals and outputting a GPS-based position result;
GPS reliability calculation means for calculating GPS positioning reliability based on the GPS-based position result;
cellular receiver means for receiving cellular-oriented signals and generating received cellular signals;
cellular position calculation means for calculating the mobile handset's position from the received cellular signals and outputting a cellular-based position result;
cellular reliability calculation means for calculating cellular positioning reliability based on the cellular-based position result; and
GPS/cellular positioning results combining means for combining the GPS-based position result and the cellular-based position result with the GPS positioning reliability and the cellular positioning reliability, wherein said GPS and cellular receiver means are adapted to receive GPS and cellular-oriented signals simultaneously.
2. A method for determining a combined GPS/cellular position result for a device, comprising the steps of:
receiving GPS-oriented signals;
receiving cellular oriented signals;
calculating a GPS-based position of the device based on the received GPS-oriented signal;
calculating a cellular-based position of the device based on the received cellular-oriented signals;
calculating a GPS positioning reliability based on the GPS-based position;
calculating a cellular positioning reliability based on the cellular-based position; and
outputting a combined GPS/cellular device position based on the GPS-based position, the GPS positioning reliability, the cellular-based position, and the cellular positioning reliability, wherein said GPS and cellular signals are received simultaneously and said GPS-based and cellular-based positions are calculated simultaneously.