Electronic assembly for range finding using radio wave signal strength
US5170172A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1991 |
| Grant date | Dec 8, 1992 |
| Priority date | — |
| Expiry date | Nov 18, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B21/0247
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A radio range finding system includes a radio frequency transmitter adapted to be located adjacent an area in which distance is to be monitored, a transmitting antenna, and a receiver unit. The receiver unit has a multiplicity of radio signal receivers each having a highly directional receiving antenna with the receiving antennae of the multiplicity of receivers having their axes of maximum sensitivity oriented in different directions, and an analyzer for determining a composite of the field strengths of the radio signals received by the receiving antennae, and providing an output indicative of the composite field strength. The receiver may detect when the composite field strength at the receiving antennae fails below predetermined values, and generate a signal at that time. The vector sum of the field strengths of the radio signals are derived from the square root of the sum of the squares of the field strengths of the several signals. The field strength signals are multiplexed and converted to a DC voltage by an RMS to DC converter. The transmit antenna is a loop comprising one or more turns shielded by two partial spaced apart shields, each connected only to the shield of the an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.