Other

Thermotrex Corporation

Trex Communications Corporation

James H Menders

Victor Hokkiu Chan

Scott Harris Bloom

Michael D Rivers

Brett A Spivey

Eric John Korevaar

In accordance with the present invention, at least three geosynchronous satellites are employed in combination, at respective known positions above a terrestrial water surface to locate an underwater terminal (vehicle). Each satellite includes a light source, and each has a controller for activating its respective light source to simultaneously transmit a light pulse, to a predetermined cell area on the terrestrial water surface, at a precisely scheduled time, t, for receipt by the underwater terminal. A computer at the terminal then evaluates the respective light pulse arrival times, t, to determine the location of the underwater terminal.

Optical global positioning system

A high speed optical receiver for receiving a substantially diminished optical signal. An optical amplifier amplifies the diminished optical signal at least several db and an ultra narrow-band filter filters the noise generated in the optical amplifier to produce a filtered amplified optical signal which is detected by a fast response photo detector. In a preferred embodiment the optical amplifier is a semiconductor laser amplifier. In this embodiment a Faraday filter provides the ultra narrow-band filtering, virtually eliminating the noise produced by the amplifier. Transmitters are described for transmitting information at a wavelength tuned to the ultra narrow-band filters.

Optical communication system

A laser communication device for transmitting and receiving information imposed on laser beams. A transmitting unit and a receiving unit are implemented based on atomic line filters. The transmitting unit includes a compact tunable laser locked to a selected atomic transition line. Information may be imposed on a laser beam by modulating the frequency thereof while maintaining its output power substantially unchanged.

Laser communication device

A portable laser communication transceiver for transmitting and receiving information imposed on laser beams. A communication signal is imposed on a laser beam having a divergence of between 1 degree and 4 degrees. The beam is directed by an operator, sighting through a telescopic viewing device, at a distant transceiver which collects light in the laser beam with a. In preferred embodiments, the transceivers are handheld and each comprises a microphone and earphones allowing operators to talk with each other. Digital information can also be transmitted from personal computers and other electronic information equipment at the location of each operator. In a preferred embodiment useful for military and surveying applications, a GPS, a compass and a laser ranging system is provided. This enables the operator to sight through a binocular to a target and determine its position in longitude, latitude and elevation. Target position information can then be transmitted to a distant transceiver which in this case could be a base transceiver.

For transmitting information via laser beams to and from other similar laser communication transceivers. Each transceiver comprises a wavelength locked beacon laser providing a beacon beam. The transceivers determine the precise location of other transceivers by detecting these beacon beams with beacon receive units comprising atomic line filters matched to the beacon wavelength. Signals are transmitted by imposing an electronic signal on laser beams produced by one or more signal laser devices. These signals are directed with precision at other transceivers, and the signal beams are detected with very narrow field of view signal receive units. In a preferred embodiment, these transceivers are installed on 66 satellites in low earth orbit and on selected mountain tops on earth to provide a global communication system.

Point-to-point laser communication device

A Voigt optical filter. Crossed polarizers are provided at the entrance and exit of a vapor cell continuing an alkali metal vapor. A magnet provides a magnetic field at 90.degree. with the axis of the cell and 45.degree. with each polarizer direction. The only light which passes through the filter is light within a narrow frequency band near the atomic transitions (absorption peaks) of the alkali metal vapor.

Voigt filter

A laser Doppler velocimeter. A laser produces a single frequency beam which is split into a probe beam and a reference beam. The probe beam is directed at a moving target and a portion of the light reflected from the target is collected, formed into a beam. Both the reference beam and the reflected beam passed through an atomic line filter in which a vapor cell is subjected to a constant magnetic field and a second magnetic field which is being oscillated. Light of the reference beam and the reflected beam passing through the filter is detected and analyzed at the frequency of oscillation of the second magnetic field and at twice that frequency. The speed of the target can be determined from measurements with respect to each beam of the amplitudes at these two frequencies.

Growing community of inventors

San Diego, CA, United States of America

James H Menders