Abstract: The device according to the invention provides a non-contacting temperature sensing device incorporating micro-bolometric detectors as the suitable infrared sensors for automotive applications. A first and second infrared sensors each include an active infrared sensing element and a temperature drift compensating element. A current bias is applied to the active infrared sensing element as well as to the temperature drift compensating element, which is identical in structure with the active infrared sensing element, and the voltage outputs of these two elements pass through a differential amplifier. The fluctuation in the substrate temperature or the ambient temperature affects the active sensing element and the compensating element in the same way, thus it is cancelled out. Instead of using one spectral band of the infrared radiation, as in the prior art, two spectral bands are used resulting in a first and second signal generated by the first and second infrared sensors.

Abstract: An imminent icing condition detector employs an infrared sensor with a focusing element to receive ambient infrared energy from a surface, particularly a road surface, and the output of the sensor is processed to provide an indication of the likelihood of icing conditions and to accordingly control a traction control substance deployment system, such as a truck that dispenses a de-icing, anti-icing, or traction substance, such as sand, salt, or other material or mixture of materials in solid granular, liquid, or mixed form.

Abstract: An aircraft ice detector system includes a radar system. The radar system provides a radar signal to a surface of the aircraft and determines whether ice is present based upon a reflected radar signal. The system can determine the type and the quantity of ice present based upon the reflected radar signal. The system can be mounted within a wing or on an external surface of the aircraft. The radar signal is preferably a low power signal.

Abstract: A method and system for sensing surface contamination on an aircraft having a control surface. A control element including the control surface is connected to the aircraft by a hinge. The method and system sense a control surface hinge moment about a line on the hinge of the aircraft. A control surface steady hinge moment coefficient is calculated from control surface hinge moment data representing the hinge moment over a period of time. An unsteady hinge moment is calculated which is dependent on the control surface steady hinge moment coefficient. By using a value which is relatively constant during uncontaminated surface conditions, this value can be compared against calculated values to check for variations. If the calculated unsteady value varies from the known uncontaminated values, a warning may be given, alerting an operator of unsafe conditions. This warning is given before a critical value is reached, allowing the operator a period of time to react to the warning.

Abstract: A modulated light source (31) transmits light pulses through an optical channel (20) to an optical sensor (10) remotely located from the cockpit and mounted proximate an aerodynamic surface (14) of an aircraft. In the absence of ice a baseline amount of light is returned inward via the optical channel. When water, ice, or de-icing fluid covers the light sensor, a detectable variable amount of light pulses are returned by the sensor inward through the optical channel, and are detected by a light detector (34) which generates an electrical output signal that varies as a function of the type, amount, and rate of substance accretion. The output signal is visually displayed (37) and the pilot may also be audibly warned.

Abstract: According to the invention, there is provided an icing detector for detecting presence of both rime ice and clear ice in air comprising an ice collecting surface facing an oncoming air stream; light emitting apparatus for emitting a light beam crossing the ice collecting surface, having a prismatic light refracting window for refracting the light beam in a first direction, when no ice is present on the ice collecting surface; light sensing apparatus in a path of the second direction, and annunciating apparatus coupled to the light sensing apparatus for annunciating presence of ice when light is sensed by the light sensing apparatus.

Abstract: In a method of detecting ice on surfaces of an aircraft, a surface of an aircraft is scanned with laser light operating at different wavelength regions in a manner whereby the surface scatters the laser light. Laser light scattered from the surface is detected. Radiation outside the wavelength bands of interest is removed prior to detection. The detected, filtered, scattered laser light is processed to reconstruct images of the surface, thereby indicating areas of ice and water on the surface. The processing takes into account the directions of scanned continuous wattage laser beams relative to the surface, laser beam geometry factors due to changing distance between the laser beams and the surface while scanning, relative signal levels, normalizations and returns from other detectors. The material of the windows of the aircraft blocks the laser beam and any stray laser light. Also, the windows of the aircraft could be treated to block the laser beam and the laser light.

Abstract: An ice detection sensor for placement on a surface of a body subject to ig includes a Pyrex glass or silicon block for disposal on the body surface, the block having a cavity therein, a diaphragm bonded to the silicon block and covering the cavity, a drive electrode disposed in the cavity and operable to deflect the diaphragm upon application of voltage between the drive electrode and the diaphragm, and a second electrode operable to detect motion of the diaphragm. The diaphragm is movable by the drive electrode when there is water covering the diaphragm and when the diaphragm is not covered and the diaphragm is not movable by the drive electrode when there is ice covering the diaphragm. The second electrode is adapted to detect movement and non-movement of the diaphragm, whereby to detect whether ice covers the diaphragm.

Abstract: The present invention is an improved ice sensor which is particularly effective in measuring and quantifying non-uniform, heterogeneous ice typically found on aircraft leading edges and top wing surfaces. In one embodiment, the ice sensor comprises a plurality of surface mounted capacitive sensors, each having a different electrode spacing. These sensors measure ice thickness by measuring the changes in capacitance of the flush electrode elements due to the presence of ice or water. Electronic guarding techniques are employed to minimize baseline and parasitic capacitances so as to decrease the noise level and thus increase the signal to noise ratio. Importantly, the use of guard electrodes for selective capacitive sensors also enables distributed capacitive measurements to be made over large or complex areas, independent of temperature or location, due to the capability of manipulating the electric field lines associated with the capacitive sensors.

Abstract: An imminent icing condition enunciator employs an infrared sensor with a focusing element to receive ambient infrared energy from a surface, particularly a road surface, and the output of the sensor is processed to provide an indication of imminent icing to the operator of, for example, an automobile or other vehicle. The device is suitably mounted to a vehicle, within a mirror enclosure so as to provide an unobstructed view of the roadway surface.

Abstract: The invention is to a system and method for detecting materials on a conductive surface and measuring the thickness and permittvity of the material. A polarized Radio Frequency signal is reflected from a conduction surface having a material thereon. The reflected de-polarized signal is then processed to determine the thickness and permittivity of the material on the conductive surface.

Abstract: A modulated light source (31) transmits light pulses via a prism (27) through a monofilament optical fiber light channel (20) to an optical sensor (10) remotely located and flush mounted to an aerodynamic surface (14) of the aircraft most likely to accrete ice. In the absence of ice little to no light is reflected inward via the light channel. When water, ice, or de-icing fluid covers the light sensor, an increased amount of light pulses are reflected inward through the single fiber optic light channel and prism assembly where they are detected by a light detector (34) which generates an electrical output signal indicative of the type, amount, and rate of ice accretion. The output signal is visually displayed (37) and the pilot may be audibly warned.

Abstract: The thickness of a semi transparent layer, such as ice, is determined by supporting the layer atop or above a light transmissive window and directing multiple light beams through the light transmissive window and into the layer. The light transmissive window has a higher index of refraction than the layer or any intermediate layer directly above the semi-transparent layer. Light beams are directed at an angle to the surface that results in total internal reflection from the outer surface of the supported semi-transparent layer. The light reflected to the rear of the window at the same but opposite angle is monitored and correlates to the thickness of the monitored layer. The spatial distribution of reflected light along the longitudinal axis of the window changes in dependence upon the thickness of the supported layer. Quantitative indications of that thickness are displayed and should that thickness exceed a prescribed level an alarm may be generated.

Abstract: A small puff of air is periodically exhausted through a semi-permeable stainless mesh (23) filter upward through the plane of the roadway surface. The puff of air is created by a miniature air pump (14) and timer, typically On one half second and Off 30 seconds. The timing can be adjustable. The puff of air is delivered to the sensor (20) through hose (5). When ice on pavement has formed over the sensor (20), it blocks the release of the air puff. This causes pressure to build up, triggering the pressure switch (16) which then turns on output switch (17) which can then be used to turn on any number of warning devices.

Abstract: A method an apparatus for detecting icing on an aircraft particularly flight surfaces by using the electrical insulating properties of ice on a conductive wing surface utilizing a simple conductive current device engageable selectively on the suspect flight surfaces.

Abstract: Ice in particular and also other substances such as water and glycol-containing anti-icing fluids can be detected and distinguished by means of differences in their optical index of refraction. A plurality of beams at different angles of incidence are multiplexed onto the reverse side of an optical surface which is embedded in a surface to be monitored or otherwise positioned in a sampling environment. The reflected beams at the different angles are measured and refractive indexes calulated form the measured reflected beams. If the calculated refractive indexes are the same at all angles, then the substance is positively identified. If the values do not agree, then there is partial coverage, and the substance may be identified by comparison with predetermined values. The system is applicable to aircraft, where in-flight and pre-flight monitoring of icing conditions and surface contamination is needed.

Abstract: A sensor arrangement for identifying various states of water on a surface of a structure, comprises a sensor element and a transmitter-receiver unit. The sensor element, adapted to be placed on the surface, has two ends and is made of an acoustically conductive material. The transmitter-receiver unit is connected between the two ends of the sensor element. The transmitter-receiver unit alternately transmits acoustic signals to each of the two ends and receives acoustic signals corresponding to the transmitted signals from each of the two ends for subsequent processing.

Abstract: The present invention is an improved ice sensor which is particularly effective in measuring and quantifying non-uniform, heterogeneous ice typically found on aircraft leading edges and top wing surfaces.In one embodiment, the ice sensor comprises a plurality of surface mounted capacitive sensors, each having a different electrode spacing. These sensors measure ice thickness by measuring the changes in capacitance of the flush electrode elements due to the presence of ice or water. Electronic guarding techniques are employed to minimize baseline and parasitic capacitances so as to decrease the noise level and thus increase the signal to noise ratio. Importantly, the use of guard electrodes for selective capacitive sensors also enables distributed capacitive measurements to be made over large or complex areas, independent of temperature or location, due to the capability of manipulating the electric field lines associated with the capacitive sensors.

Abstract: An ice detector and deicing fluid effectiveness monitoring system for an aircraft is disclosed. The ice detection portion is particularly suited for use in flight to notify the flight crew of an accumulation of ice on an aircraft lifting and control surfaces, or helicopter rotors, whereas the deicing fluid effectiveness monitoring portion is particularly suited for use on the ground to notify the flight crew of the possible loss of the effectiveness of the deicing fluid. The ice detection portion comprises a temperature sensor and a parallel arrangement of electrodes whose coefficient of coupling is indicative of the formation of the ice, as well as the thickness of the formed ice. The fluid effectiveness monitoring portion comprises a temperature sensor and an ionic-conduction cell array that measures the conductivity of the deicing fluid which is indicative of its concentration and, thus, its freezing point.

Abstract: An apparatus for detecting ice includes a heat flow sensor which senses the rate of flow of heat through a member. At the same time, the temperature differential across the member is determined. Based on the temperature differential, it is possible to calculate a theoretical heat flow rate based on the assumption that there is no ice on the member. If ice is present on the surface of the member, the actual heat flow rate will be significantly less than the calculated or theoretical heat flow rate. It is contemplated that the apparatus and method of this invention will be particularly useful in conjunction with the detecting of the presence of ice on a wing of an aircraft.

Abstract: A method and an apparatus for detecting and identifying a contaminant, such as ice, on the surface of a structure, such as a wing, are disclosed. The apparatus has a probe having a delay block with an interface apt to be placed flush with the surface of the structure and two faces at the same angle of inclination relative to the interface and having transmission and reception transducers each oriented perpendicularly to one of the faces. The block has an acoustic impedance lying in the range of 0.7 to 3.times.10.sup.6 kg/m.sup.2.s. It further has an energization and analysis unit for applying an electrical energization pulse to the transmission transducer and comparing the amplitude and the phase of the echo from the interface with a reference echo corresponding to no contamination.

Abstract: The present invention is an improved ice sensor which is particularly effective in measuring and quantifying non-uniform, heterogeneous ice typically found on aircraft leading edges and top wing surfaces. In one embodiment, the ice sensor comprises a plurality of surface mounted capacitive sensors, each having a different electrode spacing. These sensors measure ice thickness by measuring the changes in capacitance of the flush electrode elements due to the presence of ice or water. Electronic guarding techniques are employed to minimize baseline and parasitic capacitances so as to decrease the noise level and thus increase the signal to noise ratio. Importantly, the use of guard electrodes for selective capacitive sensors also enables distributed capacitive measurements to be made over large or complex areas, independent of temperature or location, due to the capability of manipulating the electric field lines associated with the capacitive sensors.

Abstract: An apparatus for identifying and measuring in real time substances overlying a surface comprises a plurality of electrodes, a temperature sensor, an electrode control system connected to the plurality of electrodes for defining an electric field, an amplitude and phase measurement system connected to the plurality of electrodes and to the electrode control system for measuring a plurality of currents responsive to the electric field and converting the currents to a measurement set and computer for storing a map comprising a partition of a vector space of predetermined characteristics of substances into regions of profiles corresponding to the substances which could be overlying the surface. The computer correlates the measurement set with the map thereby identifying and quantifying the substances overlying the surface and generates an output signal corresponding to the identity and quantity of substances overlying the surface.

Abstract: Method and apparatus for detecting icing, particularly on airfoils such as helicopter rotor blades, by detecting warming caused by latent heat released as water freezes. The sensors may be multiple or single, contact or remote.

Abstract: A detector system for detecting the formation of ice on an aircraft outer surface, e.g. wing skin. The ice detector system utilizes a light source, light detector and temperature sensor coupled together for providing signals representative of icing which may be utilized to provide an alarm to the cockpit of the aircraft. Built In Test Equipment (BITE) is also included in the detector system for system failure indication to the pilot of the aircraft.

Abstract: An apparatus and method for detection of icing onset and ice thickness upon an accretion surface utilizing ultrasonic echo ranging techniques, including propagation of ultrasonic waves through a buffer block. A portion of the wave energy is reflected by reference reflection means and another portion of the wave energy is propagated to the ice accretion surface and to a reflecting interface. The reflecting interface is represented either by the accretion surface in absence of icing, or by a thin ice layer at the icing onset, or by the ice/air interface of an ice layer accreted upon the accretion surface. Reflected waves are transduced to electrical signals. Relative signal amplitudes and time delays provide measures of particular icing conditions upon the accretion surface, and are appropriately resolved into calibrated signals indicating icing onset, ice thickness, and ice accretion rate.

Abstract: A source sends light towards a receiver through an optical channel, a part of which has an interface with the external environment. The light that reaches this interface is reflected towards the receiver when the external environment is in contact with air and is refracted towards the external environment in the presence of water or ice. In streaming down the interface, the rain creates a modulation, not created by ice, in the signal of the receiver. The circuits downline of the receiver search for this modulation to determine whether the modifications of the signal of the receiver are due to rain or to ice.

Abstract: A system and method for detecting the state and thickness of water accumulation on a surface incorporates a plurality of spaced, thin, electrically resonant circuits bonded to the surface and a radio frequency transmitter for exciting the circuits to resonance. A receiver detects the resonant signal from each circuit, determines the resonant frequency and quality factor of the circuit and correlates that information with predetermined data representing changes in resonant frequency and quality factor as a function of liquid water and ice accretion to thereby establish the state and thickness of water overlaying the circuits.

Abstract: An ice detector circuit for sensing an ice deposition on a sensing surface of an ice detector probe from an air mass flowing relative to the probe. The probe includes a heater to heat the sensing surface and a temperature sensor for sensing the sensing surface temperature during heating. The temperature sensor provides the circuit with an output having a level varying as a function of the sensing surface temperature. The circuit includes a controller which selectively energizes the heater, a timer which provides a timing output representative of a time interval elapsed between selected temperature sensor output levels, and computing means, such as a microprocessor, which computes an output representative of ice deposition as a function of a predetermined relationship between ice deposition and the timing output.

Abstract: An improved ice detector has a vibrating element which has a front portion and vibrating means suitably disposed with respect to the vibrating element for exciting the vibrating element into vibration and means for sensing a shift of the frequency of vibration of the vibrating element resulting from a change of mass of the vibrating element due to ice accumulating thereon. The improvement is characterized in that the ice detector is supported with respect to a surface exposed to an air stream such that a cap on which ice forms and which is disposed on the front portion of the vibrating element, is exposed to the air stream and is formed to be substantially conformal to such surface.