Systems and methods of reducing timing measurement error due to clock offset
US9222785B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 2013 |
| Grant date | Dec 29, 2015 |
| Priority date | — |
| Expiry date | Jun 25, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S5/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Navigation systems for use in indoor environments may include a navigation system that can calculate a time of flight of signals between a navigation device and a WiFi® Access Point. Such a calculation can be more accurate not just by using more accurate oscillators in devices, but by correcting a relative error between two devices. This relative error may be found by determining a timing offset correction, a difference in accuracy between the navigation device and the WiFi® Access Point. This may be performed by performing a fine frequency estimation on a long training field or by receiving a parts per million (ppm) offset from another device. Once the ppm offset is determined, the accuracy of the navigation device can be improved by a factor of 50 using a series of equations described in the disclosure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.