Passive keyless entry system
US4942393A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 1988 |
| Grant date | Jul 17, 1990 |
| Priority date | — |
| Expiry date | May 27, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/041
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A passive keyless entry system is disclosed that is specifically adapted for use with automotive vehicles. The system is designed to automatically unlock the vehicle as the operator approaches the vehicle. The system is further designed to automatically lock the vehicle as the operator, carrying the beacon, moves away from the vehicle. The system includes a portable beacon that is carried by the operator, a receiver/controller located in the vehicle, and an antenna connected to the receiver/controller for receiving the encoded transmission from the beacon. The beacon includes a motion sensor to conserve battery life when the beacon is stationary. Transmission between the beacon and the receiver/controller is characterized by a magnetically coupled radio frequency signal embodying differential phase encoded data with error correction coding of the data to enhance noise immunity and signal discrimination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.