Radio location with enhanced Z-axis determination
US5652592A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1995 |
| Grant date | Jul 29, 1997 |
| Priority date | — |
| Expiry date | Jun 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S5/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An enhanced system for calculating the Z-Axis, or relative height or altitude, of a radio beacon. The present invention uses a barometric pressure sensing device co-located with the radio emitter to transmit data representing relative altitude. To further enhance the Z-Axis determination, one or several barometric sensors, located at known heights, are positioned around the city to provide real time barometric data. This real time data is used to form a differential correction factor which is compared to the 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. As an alternative to differential readings from "known" altitude barometric sensors, the X,Y position of the radio emitter itself, or a check-in by a user, can be used to determine times when the radio emitter is at a known altitude thus providing occasional positions for "self" correction. Further, a mobile barometric reference, with a known Z-axis, can be purposely brought in proximity…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.