Asynchronous local position determination system and method
US7342538B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 30, 2004 |
| Grant date | Mar 11, 2008 |
| Priority date | — |
| Expiry date | Jul 11, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/37
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In a local positioning system, the land-based transmitters include free running oscillators or oscillators free of clock synchronization with any remote oscillator. A reference receiver receives the ranging signals from different transmitters and generates timing offset information, such as code phase measurements. The timing offset information is then communicated back to transmitters. The temporal offset information indicates relative timing or phasing of the different transmitted ranging signals to the reference receiver. The transmitters then transmit the temporal offset information with the ranging signals, such as modulating the transmitted code by the timing offset information. A mobile receiver is operable to receive the ranging signals and timing offset information in a same communications path, such as on a same carrier. Position is determined with the temporal offset information and the ranging signals. The temporal offset information for the various transmitters allows the mobile receiver to more accurately determine position than in an unsynchronized system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.