Abstract: An optical sensor for an aircraft includes two detectors, a light source, and a controller. The detectors are oriented along detector paths and have tilt angles and fields of view. The detectors are configured to detect light reflected from an illumination volume and to generate detector signals that correspond to intensities of detected light. The tilt angles are equal such that each detector is oriented in an opposite direction within a plane containing a light source path and the detector paths. The light source is oriented along the light source path and is configured to illuminate the illumination volume which overlaps with the fields of view within a predetermined distance range. The controller is configured to receive the detector signals, detect whether a cloud is present based upon the detector signals, determine a cloud phase, and calculate a density of the detected cloud.

Abstract: A system for determining parameters of a cloud atmosphere within a wind tunnel. The system includes: a light projector configured to project a pulse of light energy into a projection field of view; at least one light detector having a detection field of view that forms a range-limited intersection with the projection field of view, the range-limited intersection having a maximum sampling range so as to exclude wall structures of the wind tunnel, wherein the at least one light detector is configured to detect a backscattered portion of the projected pulse of light energy backscattered from within the range-limited intersection; and a cloud parameter calculator configured to determine parameters of the cloud atmosphere based on the backscattered portions detected.

Abstract: A method of operating an optical icing conditions sensor includes transmitting a first light beam with a first transmitter and a second light beam with a second transmitter, thereby illuminating two illumination volumes. A first receiver receives the first light beam. A second receiver receives the second light beam. A controller measures the intensity of light received by the first and second receivers. The controller compares the intensities to threshold values and determines if either intensity is greater than the threshold values. The controller determines a cloud is present if either intensity is greater than the threshold values. The controller calculates a ratio of the intensities if a cloud is present. The controller determines, using the ratio, whether the cloud contains liquid water droplets, ice crystals, or a mixture of liquid water droplets and ice crystals.

Abstract: A system for determining parameters of a cloud atmosphere within a wind tunnel. The system includes: a light projector configured to project a pulse of light energy into a projection field of view; at least one light detector having a detection field of view that forms a range-limited intersection with the projection field of view, the range-limited intersection having a maximum sampling range so as to exclude wall structures of the wind tunnel, wherein the at least one light detector is configured to detect a backscattered portion of the projected pulse of light energy backscattered from within the range-limited intersection; and a cloud parameter calculator configured to determine parameters of the cloud atmosphere based on the backscattered portions detected.

Abstract: A method of operating an optical icing conditions sensor includes transmitting, with a transmitter, a light beam and thereby illuminating an illumination volume. A receiver array receives light over a range of receiving angles. The receiver array is configured to receive light having the wavelength over a receiver array field of view which overlaps with the illumination volume. A controller measures an intensity of light received by the receiver array. The controller determines that a cloud is present if the intensity is greater than a threshold value. The controller calculates scattering profile data of the light received by the receiver array if a cloud is determined to be present, which includes an angle of a scattering intensity peak within the range of receiving angles and a breadth of the scattering intensity peak. The controller estimates a representative droplet size within the cloud using the scattering profile data.

Abstract: A method of operating an optical icing conditions sensor includes transmitting a first light beam with a first transmitter and a second light beam with a second transmitter, thereby illuminating two illumination volumes. A first receiver receives the first light beam. A second receiver receives the second light beam. A controller measures the intensity of light received by the first and second receivers. The controller compares the intensities to threshold values and determines if either intensity is greater than the threshold values. The controller determines a cloud is present if either intensity is greater than the threshold values. The controller calculates a ratio of the intensities if a cloud is present. The controller determines, using the ratio, whether the cloud contains liquid water droplets, ice crystals, or a mixture of liquid water droplets and ice crystals.

Abstract: An optical sensor for an aircraft includes two detectors, a light source, and a controller. The detectors are oriented along detector paths and have tilt angles and fields of view. The detectors are configured to detect light reflected from an illumination volume and to generate detector signals that correspond to intensities of detected light. The tilt angles are equal such that each detector is oriented in an opposite direction within a plane containing a light source path and the detector paths. The light source is oriented along the light source path and is configured to illuminate the illumination volume which overlaps with the fields of view within a predetermined distance range. The controller is configured to receive the detector signals, detect whether a cloud is present based upon the detector signals, determine a cloud phase, and calculate a density of the detected cloud.

Abstract: Apparatus and associated methods relate to determining an effective size, quantity, shape, and type of water particles in a cloud atmosphere based on differences in amplitudes of optical signals backscattered at different backscattering angles. Off-axis backscattering—backscattering at angles other than 180 degrees—is affected by the effective size, quantity, shape, and type of water droplets. Detected amplitudes of optical signals that are backscattered at different angles are used to indicate the effective size, quantity, shape, and type of water particles in the cloud atmosphere. In some embodiments, optical emitters and detectors are configured to measure amplitudes of optical signals backscattered at backscattering angles of both on-axis—180 degrees—and off-axis varieties.

Abstract: A multi-fiber optical sensor system includes a light source configured to generate light energy, a transmitter fiber configured to receive the light energy from the light source and to project light energy out of a projecting end of the transmitter fiber over a transmitter fiber field of view, and a plurality of receiver fibers. Each of the plurality of receiver fibers has a receiving end aligned proximate and substantially parallel to the projecting end of the transmitter fiber and is configured to receive a received portion of the projected light energy reflected from a target within a receiver field of view. The multi-fiber optical sensor system also includes a lenslet array configured to shape the transmitter fiber field of view and give the transmitter field of view a finite cross-sectional area.

Abstract: Apparatus and associated methods relate to a system for detecting foreign object debris ingested into an aircraft engine. The system detects such foreign object debris by projecting a beam of light over an inlet of the aircraft engine. When foreign object debris is ingested into the aircraft engine, it intercepts the beam of light and scatters a back-scattered portion of the intercepted beam of light. An optical detector is configured to detect the back-scattered portion of the intercepted beam of light. A processor is configured to determine whether foreign object debris is ingested by the aircraft engine based on a comparison of a threshold value with a signal indicative of the back-scattered portion generated by the optical detector.

Abstract: Apparatus and associated methods relate to ranging of objects in a scene based on difference images indicative of only objects in the scene that have ranges within a subrange. The difference images are calculated by taking differences of two images, each of which captures light reflected by objects in the scene that have ranges within range domains that are different from one another. Thus, each of the difference images includes light reflected by only those objects located at ranges that are included in one of the range domains but not the other. These range domains are controlled by the timing of operation of a fast shutter. In some embodiments, the fast shutter includes an electro-optical modulator between two polarizing filters. The electro-optical modulator can rapidly change the polarization of the light transmitted therethrough such that the second polarizing filter either transmits or blocks the light.

Abstract: Apparatus and associated methods relate to a system for detecting foreign object debris ingested into an aircraft engine. The system detects such foreign object debris by projecting a beam of light over an inlet of the aircraft engine. When foreign object debris is ingested into the aircraft engine, it intercepts the beam of light and scatters a back-scattered portion of the intercepted beam of light. An optical detector is configured to detect the back-scattered portion of the intercepted beam of light. A processor is configured to determine whether foreign object debris is ingested by the aircraft engine based on a comparison of a threshold value with a signal indicative of the back-scattered portion generated by the optical detector.

Abstract: Apparatus and associated methods relate to sampling a large volume of a cloud atmosphere so as to obtain a large signal response from even a sparse distribution of water droplets in the cloud atmosphere. Such a volume can be probed by projecting an uncollimated optical beam into the cloud atmosphere and sampling the signal backscattered from the water droplets located within the probed volume. The uncollimated optical beam can be generated by projecting a diverging pulse of light energy from a polished end of a first optical fiber. A second optical fiber can be used to receive the optical signal backscattered from the cloud atmosphere. The second optical fiber can also have substantially the same field of view as the first optical fiber, so as to receive signals from a volume of the cloud atmosphere that is substantially commensurate with the probed volume.

Abstract: A system for determining parameters of a cloud atmosphere within a wind tunnel. The system includes: a light projector configured to project a pulse of light energy into a projection field of view; at least one light detector having a detection field of view that forms a range-limited intersection with the projection field of view, the range-limited intersection having a maximum sampling range so as to exclude wall structures of the wind tunnel, wherein the at least one light detector is configured to detect a backscattered portion of the projected pulse of light energy backscattered from within the range-limited intersection; and a cloud parameter calculator configured to determine parameters of the cloud atmosphere based on the backscattered portions detected.

Abstract: Apparatus and associated methods relate to determining an effective size, quantity, shape, and type of water particles in a cloud atmosphere based on differences in amplitudes of optical signals backscattered at different backscattering angles. Off-axis backscattering—backscattering at angles other than 180 degrees—is affected by the effective size, quantity, shape, and type of water droplets. Detected amplitudes of optical signals that are backscattered at different angles are used to indicate the effective size, quantity, shape, and type of water particles in the cloud atmosphere. In some embodiments, optical emitters and detectors are configured to measure amplitudes of optical signals backscattered at backscattering angles of both on-axis—180 degrees—and off-axis varieties.

Abstract: Provided is an imaging device including a body, an x-ray detector assembly attached to the body, and an x-ray source assembly attached to the body. The x-ray detector assembly includes a telescopic actuator movable between a retracted position and an extended position, and an x-ray detector attached to the telescopic actuator.

Abstract: An aircraft ice detection system is configured to determine a condition of a cloud and includes a radar transmitter, a radar receiver, optics and a splitter. The radar transmitter is configured to produce quasi-optical radiation. The optics are configured to direct the quasi-optical radiation from the radar transmitter to the cloud and receive reflected quasi-optical radiation from the cloud. The radar receiver is configured to receive the reflected quasi-optical radiation from the optics and the splitter is configured to direct the reflected quasi-optical radiation from the optics to the radar receiver.

Abstract: Provided is an imaging device including a body, an x-ray detector assembly attached to the body, and an x-ray source assembly attached to the body. The x-ray detector assembly includes a telescopic actuator movable between a retracted position and an extended position, and an x-ray detector attached to the telescopic actuator.

Abstract: An aircraft ice detection system is configured to determine a condition of a cloud and includes a radar system, a lidar system, optics and a dichroic filter. The radar system is configured to project quasi-optical radiation to the cloud and receive reflected quasi-optical radiation from the cloud. The lidar system is configured to project optical radiation to the cloud and receive reflected optical radiation from the cloud. The optics are configured to direct the quasi-optical radiation and the optical radiation to the cloud and receive the reflected quasi-optical radiation and the reflected optical radiation from the cloud. The dichroic filter is configured to direct the quasi-optical radiation from the radar system to the optics, direct the optical radiation from the lidar system to the optics, direct the reflected quasi-optical radiation from the optics to the radar system and direct the reflected optical radiation from the optics to the lidar system.

Abstract: Apparatus and associated methods relate to reliably determining both size of large water droplets and density of small water droplets in a multi-modal cloud atmosphere. A pulsed beam of light is projected into the cloud atmosphere and a receiver receives a reflected portion of the projected pulsed beam backscattered by the cloud atmosphere. The received reflected portion is split into first and second parts. First and second parts are directed to first and second detectors, each having a different gain. A ratio of the gains of the first and second detector is greater than 3:1, thereby providing a low-gain detector for producing unsaturated signals indicative of scintillation spike reflection by large water particles and a simultaneous high-gain detector for producing signals indicative of range-resolved reflections by numerous small water particles.