초록 ▼

An airborne Icing Hazard Detector for aircraft uses dual frequency radar beams which are transmitted into a cloud ahead of the aircraft. The reflected signals at each of the two frequencies are compared and processed to determine the presence, amount and location of regions of liquid water in the cl

An airborne Icing Hazard Detector for aircraft uses dual frequency radar beams which are transmitted into a cloud ahead of the aircraft. The reflected signals at each of the two frequencies are compared and processed to determine the presence, amount and location of regions of liquid water in the cloud. The presence of liquid water is determined as a result of liquid water attenuating the power of one of the signals a greater amount than the other signal, due to different attenuation characteristics of the two signals at the two frequencies. A temperature sensor provides ambient temperature information to determine if the detected liquid water is super-cooled. Upon detection of a predetermined amount of liquid water and the determination that it is super-cooled, an advance warning indication is provided to allow the pilot to avoid flying through the volumetric region of supercooled liquid water and risking ice formation on the aircraft.

대표청구항 ▼

Apparatus for detecting the presence of a region containing super-cooled liquid water or SLW in a cloud in a flight path ahead of an aircraft, comprising: means for transmitting a first radar beam signal at a first predetermined frequency into the cloud in front of the aircraft; means for transmitti

Apparatus for detecting the presence of a region containing super-cooled liquid water or SLW in a cloud in a flight path ahead of an aircraft, comprising: means for transmitting a first radar beam signal at a first predetermined frequency into the cloud in front of the aircraft; means for transmitting a second radar beam signal at a first predetermined frequency into the cloud in front of the aircraft; one of the radar beam signals at the first or second predetermined frequencies exhibiting significantly different attenuation from propagation of that signal through the region of liquid water than the other one of the radar beam signals; the first and second transmitted radar beam signals reflecting from the cloud and creating first and second reflected signals which are received at the aircraft and which have the first and second predetermined frequencies, respectively; means for determining the power of the first and second reflected signals received at the aircraft and for supplying first and second received signals having magnitudes related to the power of the reflected signals received at the aircraft; means for sensing the temperature ambient of the aircraft and supplying a temperature signal representative of the ambient temperature; processor means responsive to the transmission of the first and second radar beam signals, the reception and magnitude of the first and second received signals, and the temperature signal, for: calculating the difference in power of the first and second received signals; detecting a region of liquid water from the difference of power of the first and second received signals; determining if the difference in power of the first and second received signals exceeds a predetermined threshold level representative of a quantity of liquid water which could result in an icing hazard; and utilizing the temperature signal to determine whether the detected region of liquid water is at a temperature in a range of 0°Celsius and less; and signalling an icing hazard condition if the difference in the magnitudes of the first and second received signals exceeds the predetermined threshold and if the determined temperature of the detected region of liquid water is 0°Celsius or less.