摘要:
A method of detecting optical subsystem failures includes emitting a pulsed light beam from a laser through a window. A reflection signal indicative of a portion of the beam reflected by the window is compared to an expected signal to monitor for degradation of an optical component.
摘要:
A method of optically determining the presence of volcanic ash within a cloud comprises emitting a circularly polarized illuminating beam within a cloud and analyzing backscatter light to identify the presence of volcanic ash within the cloud. The method further includes determining the degree to which the cloud has altered the polarization state of the emitted beam. The index of refraction of the backscatter light and the opacity of the backscatter light are also analyzed.
摘要:
A method includes checking an optical detector with a field of view for degradation by: directing the optical detector to a surface of an object in the field of view, wherein the surface is positioned at a given distance from the optical detector, and wherein the surface has a known reflectance; detecting an optical return from the surface with the optical detector to generate a return signal; and determining whether the return signal is representative of a degraded signal. The method includes outputting an alert for maintenance action if the return signal is indicative of a degraded signal.
摘要:
A system includes a first sensor positioned to sense presence of a contrail in a first volume, wherein the first volume at least partially overlaps an expected volume of a contrail proximate an aircraft. A second sensor is positioned to sense a background reference in a second volume, where the second volume does not overlap the expected volume of a contrail proximate an aircraft. A controller is operatively connected to the first and second sensors. The controller includes machine readable instructions configured to cause the controller to utilize data input from both the first and second volumes to determine if a contrail is present from the aircraft. A system includes machine readable instructions configured to cause the controller to predict persistence of contrails on an intended route through the volume of airspace and to determine an improved route and/or propulsion operation to reduce contrail formation and persistence relative to the intended route.
摘要:
In accordance with at least one aspect of this disclosure, a method of detecting a fault in a plurality of optical detectors includes receiving a first return beam from a first optical detector interrogation beam to generate a first optical signal indicative of an atmospheric condition from a first location on board the aircraft and receiving a second return beam from a second optical detector interrogation beam to generate a second optical signal indicative of the atmospheric condition from a second location on board the aircraft. The method includes, comparing each of the first and second optical signals with a baseline value to determine whether there is a fault in at least one optical detector of the plurality of optical detectors.
摘要:
A method of optically determining the presence of volcanic ash within a cloud comprises emitting a circularly polarized illuminating beam within a cloud and analyzing backscatter light to identify the presence of volcanic ash within the cloud. The method further includes determining the degree to which the cloud has altered the polarization state of the emitted beam. The index of refraction of the backscatter light and the opacity of the backscatter light are also analyzed.
摘要:
A cloud phase detection system can include a light receiver system configured to receive reflected light from a cloud, and a cloud phase module operatively connected to the light receiver system and configured to calculate a fourth Stokes parameter and a multiple scattering ratio (MSR) parameter based on the reflected light. The cloud phase module can be configured to determine a phase of a cloud based on a relationship between the fourth Stokes parameter and the MSR parameter.
摘要:
A gas detection system includes a first optical fiber bundle connected to a first multi-pass cell for connecting the first multi-pass cell to a Raman spectrum analyzer. A second optical fiber bundle is connected to the first multi-pass cell for connecting the first multi-pass cell to a second multi-pass cell. The second optical fiber bundle can include a delay coil configured to provide temporal spacing between spectral returns from the first multi-pass cell and from the second multi-pass cell. The first and second multi-pass cells can be biconic multipass cells with a the first optical fiber bundle directed toward a first D-mirror, which is directed toward a T-mirror, which is directed toward a second D-mirror, which is directed toward the second optical fiber bundle. The D-mirrors can be on an opposite end of the first multi-pass cell from the T-mirror and the first and second optical fiber bundles.
摘要:
A method of optically detecting the presence of a bimodal droplet size distribution in the atmosphere. The method comprising monitoring statistical fluctuations in a backscattered signal received from a series of pulsed laser light beams directed into a cloud and analyzing the statistics of the fluctuations of the backscattered signals to identify the presence of larger diameter droplets.
摘要:
A method of detecting optical subsystem failures includes emitting a pulsed light beam from a laser through a window. A reflection signal indicative of a portion of the beam reflected by the window is compared to an expected signal to monitor for degradation of an optical component.