Terrain awareness system

Abstract

A terrain awareness system (TAS) provides LOOK-AHEAD/LOOK-DOWN as well as LOOK-UP terrain advisory and warning indications to the pilot of an aircraft of a hazardous flight condition. The TAS includes an airport data base as well as terrain data base that is structured to provide various resolutions depending on the topography of the particular geographic area of interest. Navigational data from a satellite-based navigational system, such as a global positioning system (GPS), is used to provide a LOOK-AHEAD/LOOK-DOWN and LOOK-UP terrain advisory and terrain warning indications based upon the current position and projected flight path of the aircraft. Since the terrain advisory and the warning signals are a function of the flight path of the aircraft, nuisance warnings are minimized.

What is claimed and desired to be secured by Letters Patent of the United States is:  
     
         1 . A warning system for an aircraft comprising: 
 first means for receiving signals representative of the instantaneous flight path angle;    second means for receiving signals from a predetermined satellite-based navigation system representative of the position of the aircraft;    third means for receiving signals representative of the altitude of an aircraft;    means for storing data representative of terrain elevation information; and    means responsive to said first means, said second means, said third means and said storing means for generating a first warning signal of a hazardous flight condition, as a function of both the position of the aircraft relative to said terrain elevation information and the flight path angle of aircraft, for a predefined area relative to the aircraft wherein said area includes areas both above and ahead of the aircraft.    
     
     
         2 . A warning system as recited in  claim 1 , wherein said predetermined satellite-based navigation system is the global positioning system GPS.  
     
     
         3 . A warning system for an aircraft comprising: 
 means for receiving signals representative of the instantaneous flight path angle of the aircraft;    means for receiving signals representative of the position of the aircraft;    means for receiving signals representative of the altitude of the aircraft;    means for storing data representative of actual terrain elevation information; and    means for generating a first warning signal of a hazardous flight condition resulting from location of a subset of said predetermined terrain information at a predetermined distance in front of the aircraft, said first warning signal generated as a function of both the position of the aircraft relative to said subset of said predetermined terrain information and the flight path angle of the aircraft.    
     
     
         4 . A warning system as recited in claim  23 , wherein said generating means includes means for determining the relationship between the flight path angle and a predetermined first datum and generating a first warning signal when a predetermined relationship between the flight path angle and said first predetermined datum exists.  
     
     
         5 . A warning system as recited in claim  24 , wherein said generating means includes means for determining the relationship between the flight path angle and a predetermined second datum and generating a second warning signal when a predetermined relationship between said flight path angle and said second predetermined datum exists.  
     
     
         6 . A warning system as recited in claim  25 , wherein parameters for determining said first predetermined datum and said second predetermined datum are configurable.  
     
     
         7 . A warning system as recited in claim  23 , wherein said predetermined distance is a function of the airspeed of the aircraft.  
     
     
         8 . A warning system as recited in claim  23 , wherein said first warning signal defines a plurality of boundaries relative to the current position and altitude of the aircraft.  
     
     
         9 . A warning system as recited in claim  28 , further including means for modifying said boundaries under predetermined conditions.  
     
     
         10 . A warning system as recited in claim  29 , wherein said modifying means includes means for modifying said boundaries as a function of the flight path angle of the aircraft.  
     
     
         11 . The warning system of  claim 1  wherein said area relative to the aircraft further includes an area below the aircraft.  
     
     
         12 . A method of providing terrain warnings for a vehicle, the method comprising: 
 receiving signals representative of an instantaneous flight path angle of the vehicle;    receiving signals representative of the position of the vehicle;    receiving signals representative of terrain elevation information; and    generating a first warning signal as a function of both the position of the vehicle relative to the terrain elevation information and the flight path angle of the vehicle for a predefined area relative to the vehicle wherein the area includes areas both above and ahead of the vehicle.    
     
     
         13 . A method of providing terrain warnings for a vehicle, the method comprising: 
 receiving signals representative of an instantaneous flight path angle of the vehicle;    receiving signals representative of the position of the vehicle;    receiving signals representative of the altitude of the vehicle;    receiving signals representative of terrain elevation information; and    generating a first warning signal as a function of a subset of the terrain elevation information at a predetermined distance in front of the aircraft, said first warning signal generated as a function of both the position of the vehicle relative to the subset of terrain elevation information and the flight path angle of the vehicle.