| 摘要 |
Ultrasonic transmitters periodically transmit ranging signals, and an ultrasonic receiver receives the ranging signals on a mobile device movable along a tracking path in a venue. The most recent, successive, historical positions at which the mobile device had been along the tracking path is determined. A current, real-time position of the mobile device is obtained by determining an intermediate estimated position of the mobile device based at least partly on the last historical position, and by averaging the intermediate estimated position, together with a variable number of the historical positions. The number of the historical positions is varied as a function of a speed of the mobile device. |
