Secure two-way communications with submerged submarines
US4995101A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 1989 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Sep 19, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/11
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method of providing secure tactical communications between a submerged submarine and an airborne platform using a pulse-modulated blue-green laser beam. During an initial acquisition mode, the airborne transceiver sends out a downlink laser beam to the ocean surface and below using a predetermined IFF code to identify the transceiver to the submarine. In the preferred embodiment the transmit optics spread the beam out into an elongated elliptically-shaped pattern to maximize coverage of the search area. When the downlink beam energy is within range of the submarine, an optical receiver on the submarine detects the beam, filters out the background light with a very narrow-band filter, and converts the light pulses to equivalent electrical pulses. A signal processor in the submarine receiver decodes the electrical pulses and verifies the IFF code to prevent the submarine from responding to a laser beam from an unfriendly source. If the IFF is verified, the submarine laser transceiver transmits a pulse-modulated uplink beam response at the same wavelength, but timed so that the light pulses are time interleaved with the downlink pulses. The uplink beam power is carefully controlled …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.