Navigation reference system
US4070671A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 18, 1975 |
| Grant date | Jan 24, 1978 |
| Priority date | — |
| Expiry date | Sep 18, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S15/874
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A set of three or more acoustic transponders positioned below the surface of the ocean is provided with logic circuitry that enables location of transponder positions merely by listening to transponder signals and also enables location of an unknown receiving station merely by listening to transponder signals. The transponders are self-synchronizing to eliminate the need for precision timing over long periods. In a first mode, each transponder transmits a signal to the surface and retransmits upon receipt of its echo to thereby provide depth data. In a second mode the transponders transmit to each other and retransmit an acknowledge signal upon receipt of a reply from one of the other transponders. This provides data to enable a remote station to calculate distances between the respective transponders. In a third mode, geographic location of the transponders is determined and the transponders continue to transmit, each resetting itself upon each transmission, and each transmitting in a master or slave relation with respect to the others thereby to enable a receiving station to determine its position with respect of the transponders by conventional methods of hyperbolic navigation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.