Raytheon Company

Jon E Leigh

Gerald P Uyeno

Sean D Keller

Benn H Gleason

Craig O Shott

Eric Rogala

Garret A Odom

Mark K Lange

Vanessa Reyna

Eric C Fest

Daniel W Brunton

Paul M Lyons

The design of an existing air-to-air missile seeker is adapted to new missions that require both active laser illumination and detection (passive or active) capabilities. The gimbal is used to point the laser beam to a desired location in a transmit FOR. This approach minimizes the size, weight and power of the sensor because only a small portion of the transmit FOR is illuminated at any instant. This minimizes the laser output required, which reduces the power to operate the laser and the power to maintain the laser at operating temperature. In existing seekers, the gimbal points the detector in the desired direction to expand its FOR. To address the limitations of coupling the laser beam into the gimbaled optical system, the gimbal cannot perform the steering function for the detector. Instead, a staring detector receives light through an off-gimbal aperture within a fixed receive FOR that overlaps the transmit FOR.

Optical sensor with dual-axis gimballed transmitter and staring detector

Optical sensors and particularly gimbaled optical sensors transmit an active signal at a given wavelength and receive passive signals over a range of wavelengths while controlling pointing without benefit of measuring and locating the active signal return. The sensor includes a Tx/Rx Aperture Sharing Element (ASE) is configured to block the received active signal (e.g. reflections off a target in a scene) and process only the passive emissions. These optical sensors may, for example, be used with guided munitions or autonomous vehicles.

Optical sensor with Tx/Rx aperture sharing element (ASE) to block detection of the received active signal

A beam steering architecture for an optical sensor is based upon a pair of Micro-Electro-Mechanical System (MEMS) Micro-Mirror Arrays (MMAs) and a fold mirror. The MEMS MMAs scan both primary and secondary FOR providing considerable flexibility to scan a scene to provide not only active imaging (to supplement passive imaging) but also simultaneously allowing for other optical functions such as establishing a communications link, providing an optical transmit beam for another detection platform or determining a range to target. A special class of MEMS MMAs that provides a 'piston' capability in which the individual mirrors may translate enables a suite of optical functions to 'shape' the optical transmit beam.

Optical sensor with micro-electro-mechanical system (MEMS) micro-mirror array (MMA) steering of the optical transmit beam

An optical sensor uses a MEMS MMA to scan a narrow laser beam over a transmit FOR to provide active illumination and to correct the beam profile (e.g., collimate the beam, reduce chromatic aberrations, correct the beam profile or wavefront). A staring detector senses light within a receive FOR that at least partially overlaps the transmit FOR. By completely eliminating the dual-axis gimbal, this sensor architecture greatly reduces the volume and weight of the optical sensor while avoiding the deficiencies of known systems associated with either fiber or free-space coupling of the laser beam into an existing receiver.

Optical sensor with MEMS MMA steered transmitter and staring detector

Polarized pixelated filter sub-array is reconfigured to reduce sensitivity to misalignment. The condition number increases more slowly than the standard polarized pixelated filter sub-array as the misalignment increases. In different embodiments, the filter sub-array is configured such that the condition number has a finite bound at &#xbd; pixel misalignment. The angular values of the polarizer filter array are determined to minimize the sensitivity of the condition number of the data reduction matrix to misalignment. This can be achieved by selecting angular values that minimize the expected value of the condition number E(CN) over the range of misalignment.

Polarized pixelated filter array with reduced sensitivity to misalignment for polarimetric imaging

An apparatus includes a chamber, a first heat exchanger, an adapter, and a second heat exchanger. The first heat exchanger includes a cold finger positioned within the chamber. The second heat exchanger is positioned around an adapter and within the chamber. The second heat exchanger is a counter flow heat exchanger to precool refrigerant entering a Joule-Thomson valve. The adapter is positioned between the cold finger and the second heat exchanger. The adapter transfers heat from a thermal load to both the cold finger and the refrigerant emitted from the Joule-Thomson valve.

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Tucson, AZ, United States of America

Jon E Leigh