Raytheon Company

Other

Michael P Easton

Casey T Streuber

Kent P Pflibsen

Curtis Alan Roys

Page Elizabeth King

An EO sensor is configured to time multiplex a primary optical channel that provides high detection sensitivity to maintain high SNR and a multi-filtered optical channel that provides detection in different measurement bands (e.g. spectral, polarization, amplitude or phase). The channels may, for example, be time multiplexed based on range to target or within each integration period of the EO sensor. The multi-filtered optical channel uses a field directing array to sample the FOV to form different optical sub-channels that are filtered by different optical filters. These sub-channels may be spatially multiplexed onto different sub-regions of the detector or may be time multiplexed onto the entire detector. The light modulator used to time multiplex the primary and multi-filtered optical channels may be used to time de-multiplex spatially overlapping regions of the FOV onto a pixel of the detector in order to detect high spatial resolution images with low resolution detectors.

Time-multiplexed broadband and multi-filtered electro-optic sensor

A digitally scanned multi-cell EO sensor comprises a low-resolution multi-cell imaging detector. An array of optical focusing elements decomposes the sensor's FOV into at least four sub-fields. A sub-field directing array and focusing optic direct the optical radiation onto the imaging detector. In a first tilt mode, the optical radiation from the sub-fields is directed into at least four spatially separated sub-regions that each map to a different detector cell. A high-resolution spatial light modulator (SLM) digitally scans the FOV to select different portions of the FOV to map onto the different detector cells to time demultiplex spatially overlapping portions of the FOV onto each detector cell to stitch together a sub-image of a selected area of the FOV up to the native resolution of the SLM.

Digitally scanned multi-cell electro-optic sensor

A motionless focus evaluation test station is provided for measuring detector position error of EO sensors that do not possess dynamic focus capability. A positionally-fixed source emits EM radiation that diverges along an optical axis of the test station. Collimating optics collimate the EM radiation and direct it along the optical axis to the EO sensor. A positionally-fixed target is placed in the path of the diverging EM radiation nominally at the focal plane of the collimating optics. The target comprises a limiting aperture that exhibits an induced shift in optical focus at different positions along the aperture such that different positions on the target are imaged to different focal planes at the detector. The detector captures an image of the target that is blurred to either side of the spatial position that is optically conjugate to the actual detector position. A processor processes the image to measure the blur as function of spatial position to measure the actual detector position and output detector position error from a desired detector position.

Motionless focus evaluation test station for electro-optic (EO) sensors

A system and method for wavefront measurement of an EO sensor is performed in-situ using the sensor's EO detector in a manner that disambiguates the local wavefront measurements for different sub-pupils in time and maximizes the dynamic range for measuring the local wavefronts. A single sub-pupil sized optical beam is traced in a spatial pattern over the EO sensor's entrance pupil to serially illuminate a temporal sequence of sub-pupils to form a serially addressed sub-pupil screen. The EO detector and video card capture a video signal for one sub-pupil at a time as the optical beam traces the spatial pattern. The video signal is routed to a computer processor that generates a spatio-temporal mapping of the spatial positions of the sub-pupils in the sub-pupil screen to the temporal positions of frames in the video signal. The computer processor uses the mapping to process the video signal to compute a wavefront estimate spanning the entrance pupil.

Serially addressed sub-pupil screen for in situ electro-optical sensor wavefront measurement

A dual-mode sensor uses the active guidance radiation as a 'guide star' to generate a wavefront error estimate for the primary optical element in-situ without interfering with the generation of either the active guidance or passive imaging guidance signals. An array of optical focusing elements performs the normal function of spatially encoding an angle of incidence of the active guidance radiation at an entrance pupil onto an active imaging detector. The array also performs an additional function of spatially encoding wavefront tilt deviations emanating from sub-pupils of an exit pupil onto the active imaging detector. A processor processes the electrical signals from the imaging detector in accordance with the respective spatial encodings to generate an active guidance signal and the wavefront error estimate for the primary optical element.

Dual-mode electro-optic sensor and method of using target designation as a guide star for wavefront error estimation

A device that relieves lubricant pressure in a divider block lubrication system into a fluid reservoir, a container, or directly back into the compressor frame to which the tubing is connected. This eliminates housekeeping, environmental, safety, and compressor component failure concerns associated with current atmospheric rupture assemblies that relieve directly to the atmosphere. The environmental compressor protection assembly contains a spring set to a pre-determined pressure. Lubricant pressure in excess of this pre-determined set pressure results in spring compression and opening of a relief path. The assembly preferably remains in a full open position and must be must be manually reset to the closed position to prevent fluid flow in the system. A preferred assembly for maintaining the valve in either the open and closed position includes two balls, one of which remains trapped behind a pin during normal operation and is forced from behind the pin during an overpressure condition, the ball being prevented by the geometry of the housing from returning without manual intervention to its operating position. The relief path can lead to a fluid reservoir, a container, or directly back into the compressor frame. Flow of lubricant through the relief path results in loss of flow to the lubrication system. This triggers an alarm in the no-flow system and shutdown of the compressor. The relief path remains open until an operator resets the device. A visual indicator shows an operator if the relief valve is open or closed.

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Tucson, AZ, United States of America

Michael P Easton