| 摘要 |
<p>An enhanced system for calculating the Z-Axis, or relative height or altitude, of a radio beacon. The present invention uses a baromatric pressure sensing device co-located with the radio emitter (203) to transmit data representing relative altitude. To further enhace the Z-Axis determination, one or several barometric sensors, located at known heights, are positioned around the city to provide real time barometric data. The real time data is used to form a differential correction factor which is compared to the time varying barometric sensor co-located with the radio emitter, thereby yielding Z-Axis accuracies of up to one (1) foot. Since the altitude essentially becomes a 'known', this information can also be used in the least squares fit algorithm to enhance the X and Y determination as well.</p> |
