Method and apparatus for loop direction finding with no ambiguity
US4724442A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 1986 |
| Grant date | Feb 9, 1988 |
| Priority date | — |
| Expiry date | May 29, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S3/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus is provided for deriving the direction of a received signal from a signal source using first and second orthogonally-mounted loop antennas and an omnidirectional antenna. In operation, output signals from each of the antennas are generated and repeatedly supplied to signal processing circuitry in a cyclical fashion as the receiver is rotated to locate the transmitter. The amplitudes of the output signals from the first and second loop antennas are then compared to determine whether the signal source is located in a null of the second loop antenna. If so, a null indication signal is generated. The phases of the output signals from the second loop antenna and the omnidirectional antenna are compared to determine whether the received signal is being received in a predetermined region of the second loop antenna. If so, an ambiguity indication signal is generated. The null indication signal and the ambiguity indication signal are then logically combined to generate a visual output representing the direction of the signal source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.