Abstract: An electro-optic system, e.g., mounted to a weapon, measures down range winds and a range-to-target for compensating the ballistic hit point. The system may include an optical light source, collimated to generate a laser spot on the target. The system may include a wind measurement receiver that captures laser light scattered from the target. The captured light may be modulated by atmospheric scintillation eddies, producing optical patterns which change in time and move with the crosswind. These patterns may be analyzed by a processor using covariance techniques in either the time-domain or the frequency-domain to determine path-integrated crosswinds and associated errors. Ranging is done by measuring the time of flight of the laser pulse to the target collecting the scattered signal from the target.

Abstract: A sensor assembly having an optical fiber, a lens in optical communication with the optical fiber, a reflective surface spaced from the lens, for reflecting light from the beam back to the lens, a partially reflective surface positioned between the reflective surface and the lens, the partially reflective surface for reflecting light from the beam back to the lens, and an alignment device for aligning the lens and reflective surface with respect to one another, such that light from the beam of light transmitted from the lens reflects from the reflective surface back to the lens. The alignment device can have a rotational component and a base component, where the rotational component rotates to align a beam of light transmitted from the lens. The rotational component can also cooperate with the base component to move axially with respect to the reflective surfaces to align the beam for optimum power.

Abstract: A sensor assembly having an optical fiber, a lens in optical communication with the optical fiber, a reflective surface spaced from the lens, for reflecting light from the beam back to the lens, a partially reflective surface positioned between the reflective surface and the lens, the partially reflective surface for reflecting light from the beam back to the lens, and an alignment device for aligning the lens and reflective surface with respect to one another, such that light from the beam of light transmitted from the lens reflects from the reflective surface back to the lens. The alignment device can have a rotational component and a base component, where the rotational component rotates to align a beam of light transmitted from the lens. The rotational component can also cooperate with the base component to move axially with respect to the reflective surfaces to align the beam for optimum power.

Abstract: The present invention is directed to a system for determining a fluid level in a vessel. The system comprises a first differential pressure transducer, a second differential pressure transducer, a pressure delivery system, and a fluid passage. The first differential pressure transducer includes a first side and a second side. The first side is selectively in fluid communication with a portion of the vessel above the fluid level. The second differential pressure transducer includes a third side and a fourth side. The third side is selectively in fluid communication with a portion of the vessel below the fluid level. The fluid passage is in fluid communication with the second side of the first transducer, the fourth side of the second transducer, and the pressure delivery mechanism.

Abstract: A method and apparatus for monitoring one or more environmental parameters using interferometric sensor(s), a cross-correlator, a two-dimensional photosensitive array and optical focusing means are described. The method and apparatus allows for near simultaneous monitoring of the parameter(s) of interest.

Abstract: A method and apparatus for detecting seismic vibrations using a series of MEMS units, with each MEMS unit including an interferometer is described. The interferometers on the MEMS units receive and modulate light from two differing wavelengths by way of a multiplexing scheme involving the use of Bragg gratings and light circulators, and an optoelectronic processor receives and processes the modulated light to discern vibrational movement of the system, which in turn allows for monitoring and calculation of a specified environmental parameter, such as seismic activity, temperature or pressure.

Abstract: A dynamic optical tag system and method that allows for operation over a wide temperature range. A variable wavelength optical source, such as a dual wavelength fiber laser, is generated by combining the outputs from two distributed feedback lasers having separate operating wavelengths using a wavelength division multiplexer (WDM). A quantum well optical modulator mounted on the front surface of a retro-reflector in the remote receiver end of the communication link is biased to modulate one of the two laser wavelengths. At higher temperatures, the optical modulator can be biased to operate at the wavelength of one of the two lasers. At a lower temperature, the optical modulator can be biased to operate at the second of the two wavelengths. The DC bias required to tune the optical modulator is reduced by operating at two separate wavelengths depending on temperature.

Abstract: A method and apparatus for detecting seismic vibrations using a series of MEMS units, with each MEMS unit including an interferometer is described. The interferometers on the MEMS units receive and modulate light from two differing wavelengths by way of a multiplexing scheme involving the use of Bragg gratings and light circulators, and an optoelectronic processor receives and processes the modulated light to discern vibrational movement of the system, which in turn allows for monitoring and calculation of a specified environmental parameter, such as seismic activity, temperature or pressure.

Abstract: A method and apparatus for monitoring one or more environmental parameters using interferometric sensor(s), a cross-correlator, a two-dimensional photosensitive array and optical focusing means are described. The method and apparatus allows for near simultaneous monitoring of the parameter(s) of interest.

Abstract: A method for monitoring changes in a gap which corresponds to changes in a particular environmental parameter using a tunable laser and interferometer at high frequency is disclosed. The laser light provided to the interferometer is swept through a small range of wavelengths. Light modulated by the interferometer is detected and a non-sinusoidal light intensity output curve is created, a reference point on the curve identified and subsequent sweep of the laser performed. The difference in time, wavelength, or frequency at the occurrence of the reference point between the two sweeps allows for measuring the relative changes in the gap and, as a result, the change in the environmental parameter.

Abstract: The present invention pertains to differential pressure transducers. In an embodiment of the invention, a differential pressure transducer includes a transducer housing, a diaphragm, a bellows, and a sensing assembly. The transducer housing, diaphragm, and bellows are coupled to form a pressure chamber. The pressure chamber is separated into two portions by the diaphragm, with each portion arranged to be filled with a process fluid. A pressure differential across the diaphragm causes displacement of the diaphragm. Such displacement is measured by the sensing assembly and used to calculate the pressure differential between the two process fluids.

Abstract: Linear variable reflector sensors can be used to measure the displacement of objects. These sensors are useful in that they can be very small, do not conduct electricity, and are resistant to electrical interference from EMI/EMP and lightning strikes. The present linear variable reflector system comprises a light source, a light transmitting member in optical communication with the light source, a sensor in optical communication with the light transmitting member. The sensor comprises a moveable transparent body, a reflective material deposited on the transparent body, and at least one film deposited over said reflective material, wherein said reflective material reflects light. Further, the linear variable reflector system comprises a detector coupled to the sensor to detect displacement of the moveable transparent body.

Abstract: A method and apparatus for quantitatively measuring the distance of an unknown variable gap is disclosed. Light is provided to two Fabry-Perot interferometers arranged in a series, one spanning the unknown gap and the other spanning a controllably variable gap. Means for verifying the positioning of the Fabry-Perot interferometer having the controllably variable gap work in conjunction with a signal processor, a correlation burst signal detector and means for conveying the light to the various system elements to perform a comparison of detector signals from the two interferometers and quantitatively establish the gap distance. The invention may also be varied to function on a time basis, include more than one source of light, possess filter means to distinguish between light sources and/or include one or more reference interferometers.

Abstract: A signal conditioner to measure the length of an interferometric gap in a Fabry-Perot sensor (interferometer). The invention includes a light source, a Fabry-Perot interferometer capable of spanning a range of gaps in response to physical changes in the environment, a second interferometer that is placed in series with the Fabry-Perot interferometer which does not filter any particular wavelengths of light but acts as an optical cross-correlator, a detector for converting the correlated light signal into electronic signals, and an electronic processor which controls system elements and generates a signal indicative of the length of the gap spanned by the Fabry-Perot sensor.

Abstract: The present invention is directed to a system for determining a fluid level in a vessel. The system comprises a first differential pressure transducer, a second differential pressure transducer, a pressure delivery system, and a fluid passage. The first differential pressure transducer includes a first side and a second side. The first side is selectively in fluid communication with a portion of the vessel above the fluid level. The second differential pressure transducer includes a third side and a fourth side. The third side is selectively in fluid communication with a portion of the vessel below the fluid level. The fluid passage is in fluid communication with the second side of the first transducer, the fourth side of the second transducer, and the pressure delivery mechanism.

Abstract: An apparatus to interrogate one or more fiber optic sensors to make high-resolution measurements at long distances between the sensor and the interrogator apparatus. The apparatus comprises a tunable light source, an optical switch for pulsing the light source, at least one sensor (e.g., a Fabry-Perot sensor) for reflecting the laser light, a fiber optic cable interconnecting the sensor with the light source, a coupler for directing the reflected light from the sensor to a detector in order to generate a digital output, and a control logic for tuning the laser light source based on the digital output from the detector. Use of a fiber Bragg grating temperature sensor is also contemplated.

Abstract: The present invention pertains to differential pressure transducers. In an embodiment of the invention, a differential pressure transducer includes a transducer housing, a diaphragm, a bellows, and a sensing assembly. The transducer housing, diaphragm, and bellows are coupled to form a pressure chamber. The pressure chamber is separated into two portions by the diaphragm, with each portion arranged to be filled with a process fluid. A pressure differential across the diaphragm causes displacement of the diaphragm. Such displacement is measured by the sensing assembly and used to calculate the pressure differential between the two process fluids.

Abstract: A dynamic optical tag system and method that allows for operation over a wide temperature range. A variable wavelength optical source, such as a dual wavelength fiber laser, is generated by combining the outputs from two distributed feedback lasers having separate operating wavelengths using a wavelength division multiplexer (WDM). A quantum well optical modulator mounted on the front surface of a retro-reflector in the remote receiver end of the communication link is biased to modulate one of the two laser wavelengths. At higher temperatures, the optical modulator can be biased to operate at the wavelength of one of the two lasers. At a lower temperature, the optical modulator can be biased to operate at the second of the two wavelengths. The DC bias required to tune the optical modulator is reduced by operating at two separate wavelengths depending on temperature.

Abstract: In a Fabry-Perot interferometer based sensor if insufficient light reflected from the sensor re-enters the fiber, the results from the Fabry-Perot interferometer-based sensor are compromised. Accordingly, a sensor assembly is provided that comprises an optical fiber having an optical axis, a lens in optical communication with the optical fiber, the lens having an optical axis and the lens capable of transmitting a beam of light, a reflective surface, the reflective surface spaced from the lens such that the beam of light transmitted from the lens is capable of reflecting from the reflective surface back to the lens, and an alignment device capable of aligning the beam of light transmitted from the lens substantially perpendicular with the reflective surface.

Abstract: A method and apparatus for monitoring one or more environmental parameters using interferometric sensor(s), a cross-correlator, a two-dimensional photosensitive array and optical focusing means are described. The method and apparatus allows for near simultaneous monitoring of the parameter(s) of interest.