System and method for detecting adverse atmospheric conditions ahead of an aircraft

Abstract

System and method for detecting adverse atmospheric conditions ahead of an aircraft. The system has multiple, infrared cameras 8 adjusted to spatially detect infrared radiance in different bands of infrared light, wherein each camera is connected to an image processing computer that processes and combines the images, and generates video display signals for producing a video display which indicates the position of the adverse atmospheric conditions relative to the aircraft. Each of the cameras is provided with a respective filter adjusted to filter infrared light with a bandwidth corresponding to infrared bandwidth characteristics of an adverse atmospheric condition from a set of adverse atmospheric conditions. The image processing computer is adapted to identify adverse atmospheric conditions, said identifying being based on threshold conditions and using the detected infrared radiance, data from a look-up table and measured parameters including information on the position and/or attitude of the aircraft. The image processing computer is further adapted to display the identified adverse atmospheric conditions as a spatial image on a display.

1 . A system for detecting adverse atmospheric conditions ahead of an aircraft, comprising
 a plurality of infrared cameras mounted on the aircraft, wherein the infrared cameras are adjusted to spatially detect infrared radiance in different bands of infrared light;
 each camera is connected to an image processing computer that processes and combines the images and generates video display signals for producing a video display which indicates the position of the adverse atmospheric conditions relative to the aircraft; 
 each of the cameras is provided with a respective filter adjusted to filter infrared light with a bandwidth corresponding to infrared bandwidth characteristics of an adverse atmospheric condition from a set of adverse atmospheric conditions; 
 the image processing computer is adapted to identify adverse atmospheric conditions, said identifying being based on threshold conditions and using the detected infrared radiance, data from a look-up table and measured parameters including information on the position and/or attitude of the aircraft; and 
 the image processing computer is further adapted to display the identified adverse atmospheric conditions as a spatial image on the display. 
   
     
     
         2 . The system of  claim 1  wherein the set of adverse atmospheric conditions includes volcanic ash, ice coated ash, water vapour and sulphur dioxide. 
     
     
         3 . The system  claim 2 , wherein the system is arranged to seek to identify both ice coated ash and water vapour, and wherein the identification of water vapour is used to confirm an identification of ice coated ash. 
     
     
         4 . The system of  claim 1  wherein the threshold conditions are pre-computed using a radiative transfer model of the atmosphere. 
     
     
         5 . The system of  claim 1 , wherein the image processing computer is arranged to determine brightness temperatures from the detected infrared radiance, and said identifying includes determining whether values related to the brightness temperatures meet the threshold conditions. 
     
     
         6 . The system  claim 1 , wherein the measured parameters include pitch angle and ambient temperature. 
     
     
         7 . The system  claim 1 , including one or more external blackened shutters against which said imaging cameras are pre-calibrated for providing in-flight calibration values. 
     
     
         8 . A method for detecting adverse atmospheric conditions ahead of an aircraft and displaying said adverse atmospheric conditions, comprising spatially detecting infrared radiance in different bands of infrared light using a plurality of infrared cameras; and, for each camera:
 i) Filtering the infrared radiation with a filter adjusted to filter infrared light with a bandwidth corresponding to infrared bandwidth characteristics of an adverse atmospheric condition in a set of adverse atmospheric conditions;   ii) identifying likely occurrences of adverse atmospheric conditions based on threshold conditions and using the detected infrared radiance, data from a look-up table and measured parameters including information on the position and/or attitude of the aircraft; and   iii) processing the identified likely occurrences of adverse atmospheric conditions to create a spatial image.   
     
     
         9 . The method of  claim 8 , including the additional step of
 iv) combining the image with images from other cameras and information on the aircraft flight path.   
     
     
         10 . The method of  claim 8 , wherein the set of adverse atmospheric conditions includes volcanic ash, ice coated ash, water vapour and sulphur dioxide. 
     
     
         11 . The method of  claim 10 , further comprising identifying likely occurrences of both ice coated ash and water vapour, wherein the identification of water vapour is used to confirm an identification of ice coated ash. 
     
     
         12 . The method of  claim 8 , wherein the threshold conditions are pre-computed using a radiative transfer model of the atmosphere. 
     
     
         13 . The method of  claim 8 , further comprising, for each camera, determining brightness temperatures from the detected infrared radiance, and wherein said identifying includes determining whether values related to the brightness temperatures meet the threshold conditions. 
     
     
         14 . The method of  claim 8 , wherein the measured parameters include pitch angle and ambient temperature. 
     
     
         15 . The method of  claim 8 , further comprising pre-calibrating the imaging cameras against one or more external blackened shutters, for providing in-flight calibration values. 
     
     
         16 . (canceled) 
     
     
         17 . A computer program product stored on a computer readable medium, comprising a readable program which when executed by a computer causes the computer to carry out a method comprising spatially detecting infrared radiance in different bands of infrared light using a plurality of infrared cameras; and, for each camera:
 i) filtering the infrared radiation with a filter adjusted to filter infrared light with a bandwidth corresponding to infrared bandwidth characteristics of an adverse atmospheric condition in a set of adverse atmospheric conditions;   ii) identifying likely occurrences of adverse atmospheric conditions based on threshold conditions and using the detected infrared radiance, data from a look-up table and measured parameters including information on the position and/or attitude of the aircraft; and   iii) processing the identified likely occurrences of adverse atmospheric conditions to create spatial image.   
     
     
         18 . The computer program product of  claim 17 , wherein the method further comprises combining the image with images from other cameras and information on the aircraft flight path. 
     
     
         19 . The computer program product of  claim 17 , wherein the set of adverse atmospheric conditions includes volcanic ash, ice coated ash, water vapour and sulphur dioxide. 
     
     
         20 . The computer program product of  claim 17 , wherein the method further comprises identifying likely occurrences of both ice coated ash and water vapour, wherein the identification of water vapour is used to confirm an identification of ice coated ash. 
     
     
         21 . The computer program product of  claim 17 , wherein the threshold conditions are pre-computed using a radiative transfer model of the atmosphere. 
     
     
         22 . The computer program product of  claim 17 , wherein the method further comprises, for each camera, determining brightness temperatures from the detected infrared radiance, and wherein said identifying includes determining whether values related to the brightness temperatures meet the threshold conditions.