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: Apparatus and associated methods relate to determining health of an electrical heater of an air data probe based on a comparison between a calculated expected value and a measured value of an electrical property of the electrical heater. The expected value of the electrical property is calculated based in part on the electrical power provided to the electrical heater and further based in part on the aircraft flight parameters and/or environmental conditions. Such aircraft flight parameters and/or environmental conditions can include at least one of: electric power source status, airspeed, air pressure, altitude, air temperature, humidity, liquid water content, ice water content, droplet/particle size distribution, angle of attack, and angle of sideslip. These aircraft flight parameters and/or environmental conditions are received via an aircraft interface.

Abstract: Apparatus and associated methods relate to determining metrics of a cloud atmosphere using time difference measurements. A light projector projects a pulse of light into a cloud atmosphere, and a light sensor detects a portion of the projected pulse of light backscattered by the cloud atmosphere. A backscatter coefficient is calculated based on peak amplitude of the detected portion. An optical extinction coefficient is calculated based on a time difference between a peak time and a post-peak time, which correspond to times at which the peak amplitude of the detected portion occurs and at which the detected portion equals or crosses a sub-peak threshold, respectively. In some embodiments, a logarithm amplifier is used to facilitate processing of signals of widely varying amplitudes. In some embodiments, the sub-peak threshold is calculated as a fraction of the peak amplitude of the detected portion.

Abstract: In one example, a method includes receiving, over an aircraft data communications bus, a plurality of non-pneumatic inputs corresponding to aircraft operational parameters. The method further includes processing the plurality of non-pneumatic inputs through an artificial intelligence network to generate an air data output value, and outputting the air data output value to a consuming system for use when a pneumatic-based air data output value is determined to be unreliable.

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.

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.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by simultaneously projecting both a collimated pulsed beam into a narrow-field projection volume and a divergent pulsed beam into a wide-field projection volume of the cloud atmosphere, and then detecting both the collimated and divergent pulsed beams backscattered from within a detection volume of the cloud atmosphere. Projection and detection are configured such that the detection volume intersects both the narrow-field and the wide-field projection volumes defining narrow-field/detection and wide-field/reception detection volumes, respectively.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by simultaneously projecting both a collimated pulsed beam into a narrow-field projection volume and a divergent pulsed beam into a wide-field projection volume of the cloud atmosphere, and then detecting both the collimated and divergent pulsed beams backscattered from within a detection volume of the cloud atmosphere. Projection and detection are configured such that the detection volume intersects both the narrow-field and the wide-field projection volumes defining narrow-field/detection and wide-field/reception detection volumes, respectively.

Abstract: Apparatus and associated methods relate to determining, based on a detected portion of a projected pulse of quasi-optical energy backscattered by water particles within a divergent projection volume of a cloud atmosphere, properties of the backscattering water particles. The pulse of quasi-optical energy is projected into the divergent projection volume of the cloud atmosphere. The divergent projection volume is defined by an axis of projection and an angle of projection about the axis of projection. The portion of the projected pulse of optical energy backscattered by water particles within the divergent projection volume of the cloud atmosphere is received and detected. Various properties of the backscattering water particles, which can be determined from the detected portion of the projected pulse backscattered by water particles can include particle density and/or particle size.

Abstract: Apparatus and associated methods relate to determining sizes of water particles in a cloud atmosphere based on a detected portion of signals generated from a single monochromatic source and backscattered by water particles in a cloud atmosphere. A backscatter coefficient and an optical extinction coefficient are calculated, based on the detected portion of signals generated from the monochromatic source and backscattered by water particles in the cloud atmosphere. A LIDAR ratio—a ratio of the optical extinction coefficient to the backscatter coefficient, is calculated. Sizes of water particles in the cloud atmosphere are estimated based on the LIDAR ratio. An output signal indicative of the estimated sizes of water particles in the cloud atmosphere is generated. Estimating sizes of water particles using signals from a single monochromatic source advantageously can alert a pilot of an aircraft of cloud conditions, without requiring multi-chromatic sources.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by comparing detected optical signals reflected from small and large sampling volumes of a cloud atmosphere. In some embodiments, an optical pulse is generated and divergently projected from a first optical fiber. A collimating lens is aligned within the divergently projected optical pulse collimating a portion thereof. The collimated and uncollimated portions of the optical pulse are projected into the small and large sampling volumes of the cloud atmosphere, respectively. The ratio of the collimated to the uncollimated portions can be optically controlled. Signals corresponding to optical pulses having different collimated/uncollimated ratios are backscattered by the cloud atmosphere, detected and compared to one another.

Abstract: Apparatus and associated methods relate to determining metrics of water particles in clouds by directing light pulses at a cloud and measuring a peak, a post-peak value and a high-frequency fluctuation of light signals reflected from the cloud. The light pulses include: a first pulse having circularly polarized light of a first wavelength; and a second pulse of a second wavelength. The reflected light signals include: a first reflected light signal having left-hand circular polarization of the first wavelength; a second reflected light signal having right-hand circular polarization of the first wavelength; and a third reflected light signal of the second wavelength. An extinction coefficient and a backscatter coefficient are determined based on the measured peak and post-peak slopes of the first and second reflected light signals. The measured high-frequency fluctuations of the three reflected light signals can be used to calculate cloud particle sizes.

Abstract: A first air data value is generated based on a first set of parameters. A second set of parameters that does not include any of the first set of parameters is processed through an artificial intelligence network to generate a second air data value. The second set of parameters is processed through a plurality of diagnostic artificial intelligence networks to generate a plurality of diagnostic air data values. Each of the plurality of diagnostic artificial intelligence networks excludes a different one of the second set of parameters. One of the second set of parameters is identified, based on the first air data value and the plurality of diagnostic air data values, as a fault source parameter that is associated with a fault condition.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by comparing detected optical signals reflected from small and large sampling volumes of a cloud atmosphere. In some embodiments, an optical pulse is generated and divergently projected from a first optical fiber. A collimating lens is aligned within the divergently projected optical pulse collimating a portion thereof. The collimated and uncollimated portions of the optical pulse are projected into the small and large sampling volumes of the cloud atmosphere, respectively. The ratio of the collimated to the uncollimated portions can be optically controlled. Signals corresponding to optical pulses having different collimated/uncollimated ratios are backscattered by the cloud atmosphere, detected and compared to one another.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by comparing detected optical signals reflected from small and large sampling volumes of a cloud atmosphere. In some embodiments, an optical pulse is generated and divergently projected from a first optical fiber. A collimating lens is aligned within the divergently projected optical pulse collimating a portion thereof. The collimated and uncollimated portions of the optical pulse are projected into the small and large sampling volumes of the cloud atmosphere, respectively. The ratio of the collimated to the uncollimated portions can be optically controlled. Signals corresponding to optical pulses having different collimated/uncollimated ratios are backscattered by the cloud atmosphere, detected and compared to one another.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by comparing detected optical signals reflected from small and large sampling volumes of a cloud atmosphere. In some embodiments, an optical pulse is generated and divergently projected from a first optical fiber. A collimating lens is aligned within the divergently projected optical pulse collimating a portion thereof. The collimated and uncollimated portions of the optical pulse are projected into the small and large sampling volumes of the cloud atmosphere, respectively. The ratio of the collimated to the uncollimated portions can be optically controlled. Signals corresponding to optical pulses having different collimated/uncollimated ratios are backscattered by the cloud atmosphere, detected and compared to one another.

Abstract: In one example, a method includes receiving, over an aircraft data communications bus, a plurality of non-pneumatic inputs corresponding to aircraft operational parameters. The method further includes processing the plurality of non-pneumatic inputs through an artificial intelligence network to generate an air data output value, and outputting the air data output value to a consuming system for use when a pneumatic-based air data output value is determined to be unreliable.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by comparing detected optical signals reflected from small and large sampling volumes of a cloud atmosphere. In some embodiments, an optical pulse is generated and divergently projected from a first optical fiber. A collimating lens is aligned within the divergently projected optical pulse collimating a portion thereof. The collimated and uncollimated portions of the optical pulse are projected into the small and large sampling volumes of the cloud atmosphere, respectively. The ratio of the collimated to the uncollimated portions can be optically controlled. Signals corresponding to optical pulses having different collimated/uncollimated ratios are backscattered by the cloud atmosphere, detected and compared to one another.

Abstract: In one example, a method includes receiving, over an aircraft data communications bus, a plurality of non-pneumatic inputs corresponding to aircraft operational parameters. The method further includes processing the plurality of non-pneumatic inputs through an artificial intelligence network to generate an air data output value, and outputting the air data output value to a consuming system for use when a pneumatic-based air data output value is determined to be unreliable.

Abstract: Apparatus and associated methods relate to determining, based on a detected portion of a projected pulse of quasi-optical energy backscattered by water particles within a divergent projection volume of a cloud atmosphere, properties of the backscattering water particles. The pulse of quasi-optical energy is projected into the divergent projection volume of the cloud atmosphere. The divergent projection volume is defined by an axis of projection and an angle of projection about the axis of projection. The portion of the projected pulse of optical energy backscattered by water particles within the divergent projection volume of the cloud atmosphere is received and detected. Various properties of the backscattering water particles, which can be determined from the detected portion of the projected pulse backscattered by water particles can include particle density and/or particle size.