Roadside beacon system
US4833481A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 20, 1987 |
| Grant date | May 23, 1989 |
| Priority date | — |
| Expiry date | Jul 20, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S1/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A roadside antenna system permitting the transmission of data to a vehicular navigation system and providing for the recalibration of positional data carried by the navigation system includes an antenna structure and transmitter system which permits the data transmission signal to be broadcast in a wide pattern. Meanwhile, the signal that provides for positional recalibration is broadcast in a high directivity signal or split beam. The positional accuracy of the navigator system is improved by performing the positional calibration only when intercepting the narrow beam pattern. Data transmission and reception can be carried out within a larger effective reception area without affecting the positional accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.