Method for measuring distance between two objects and method for controlling access to an object or the use thereof, in particular access control and driving authorization for a motor vehicle
US7061369B2 · kind B2 · utility
17Cited by
5References
11Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 20, 2002 |
| Grant date | Jun 13, 2006 |
| Priority date | — |
| Expiry date | Jul 16, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C2209/61
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A bidirectional dialogue is carried out between a portable code emitter (15) and a base station (1) for access to a motor vehicle. Both signals are correlated with each other and the dialogue repeated at an altered carrier frequency. The distance of the code emitter (15) from the base station (11) is determined from the difference in two phase difference measurements between the sent and received signal in one station (11 or 15). Access to, or use of the motor vehicle (10) is only permitted when the code emitter (15) is within a certain distance from the motor vehicle (10).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.