Abstract: The present invention includes a system and method of use for communications from an in-air platform to a submerged platform. The system includes a laser positionable on the in-air platform above a water medium that sends a pulsed information-bearing laser beam containing a modulated communications signal to create and react in a non-linear regime manner with the water medium at an air/water interface. The beam vaporizes and optically breaks down a portion of the water medium, creates a shock wave and generates bubble oscillations at the vaporized portion. An acoustic sensor on the submerged platform detects these shock wave oscillations within the water medium and a demodulator-decoder that identifies these broadband acoustic transients that contain deterministically placed energy and demodulates-decodes the acoustic transients into the transmitted communications signals from the in-air platform.

Abstract: The present application provides a linear mechanism for optical-to-acoustic energy conversion for optoacoustic communication from an in-air platform to an undersea vehicle. Signals used in underwater acoustic telemetry applications are capable of being generated through the linear optoacoustic regime conversion process. A number of issues concerning linear optoacoustic communication is addressed that lead to a formulation of a linear regime optoacoustic communication scheme. The use of oblique laser bean incidence at an air-water interface to obtain considerable in-air range from the laser source to the vehicle is also addressed. The effect of oblique incidence on in-water range is addressed as well. Optimum and sub-optimum linear optoacoustic sound-generation techniques for selecting the optical wavelength and signal frequency for optimizing in-water range are identified.

Abstract: An apparatus for enabling acousto-optic communication comprising an in-water platform comprising means for emitting an acoustic signal to an acousto-optic interaction zone, an in-air platform comprising the ability for transmitting a first optical interrogation beam, the ability for receiving a portion of the first interrogation beam and a second laser beam formed from the reflection of the first interrogation beam off of the acousto-optic interaction zone, the ability for measuring and outputting a plurality of optical interferences between the portion of the first interrogation beam and the second reflected beam, and a signal converter receiving as input the plurality of optical interferences and outputting an electrical signal representing the received acoustic telemetry signal at the interrogation point at the air-water interface.

Abstract: A device (gage, data station, and software) and method to measure mean radius and deviations from mean radius of nominally cylindrical or conical shapes in a plane perpendicular to the nominal axis of revolution using curvature measurements at uniformly spaced intervals about the circumference is described. The system divides the contour of interest into equal segments and measures the local curvature at each point. The group of measurements combines with a closure constraint to produce a condition of mathematical overcompleteness. This is used to minimize the accumulation of measurement error.

Abstract: A system for monitoring the security of one or more persons in a waterside environment and for providing a failure proof indication of when such person falls into the water. The system includes a portable transmitter worn about the body of the person whose security is being monitored in a location which insures its submergence when the person falls into the water. Transmissions from the portable unit, which may be either time shared or the result of an interrogation from a base station, are monitored at a base station. Continuous presence of the transmitted signal from each portable unit inhibits an alarm condition at the base station, but if the transmitted signal is not received, or is not received for a predetermined time period, the alarm condition is activated and the portable unit not transmitting is identified. The lack of a transmitted signal indicates a "man overboard" condition resulting from the transmitter being immersed in the water and transmissions thus blocked.