Integrated hover display with radar altitude predictor for indicating height above ground

Abstract

A flight control system includes a primary flight display having a hover display which facilitates operations in DVE conditions. The hover display includes a radar altitude display, heading drift symbology and lateral drift symbology which assists pilots in the detection of drift, which is common in DVE situations and to provide the pilot with a salient cue pertinent to the approach to hover and landing.

1 . A system to enhance situational awareness in a rotary wing aircraft, comprising: 
 a sensor system that receives a multitude of environmental information including a radar altitude;    a data fusion processor in communication with said sensor system which compiles said environmental information into a combined output; and    a radar altitude display in communication with said data fusion processor, said radar altitude display includes a height above ground pointer relative a radar altitude scale and an altitude ascent/descent trend tape that projects from said height above ground pointer to indicate an altitude ascent/descent trend.    
   
   
       2 . The system as recited in  claim 1 , wherein said altitude ascent/descent trend tape is overlaid on said radar altitude scale.  
   
   
       3 . The system as recited in  claim 1 , wherein said radar altitude display displays a current height above ground value as a numerical value within said radar altitude display.  
   
   
       4 . The system as recited in  claim 3 , wherein said numerical value is equivalent to a current value of said height above ground pointer.  
   
   
       5 . The system as recited in  claim 1 , wherein said altitude ascent/descent trend tape projects from a current value of said height above ground pointer along an arc of the radar altitude display to a future height above ground value on said radar altitude scale.  
   
   
       6 . The system as recited in  claim 5 , wherein said altitude ascent/descent trend tape projects from said current value of said height above ground pointer according to the following algorithm: Future altitude=Current value of radar altitude+(Rate of closure*Predictor Time Constant) 
 Where:    Rate of closure=moving average of value of radar altitude over a period of time; and    Predictor time constant=amount of time in the future to compute the radar altitude.    
   
   
       7 . The system as recited in  claim 6 , wherein said Rate of closure is calculated over a period of two seconds, sampled at 10 HZ and measured in feet per second and said Predictor time constant is set at 6 seconds  
   
   
       8 . The system as recited in  claim 1 , wherein said radar altitude display is incorporated into a primary flight display.  
   
   
       9 . The system as recited in  claim 1 , wherein said radar altitude display includes a round dial-like display.  
   
   
       10 . A radar altitude display, comprising: 
 a radar altitude scale;    a height above ground pointer relative said radar altitude scale; and    an altitude ascent/descent trend tape that projects from said height above ground pointer along an arc of said radar altitude scale to indicate an altitude ascent/descent trend.    
   
   
       11 . The radar altitude display as recited in  claim 10 , wherein said radar altitude display displays a current height above ground value as a numerical value within said radar altitude display.  
   
   
       12 . The radar altitude display as recited in  claim 11 , wherein said numerical value is equivalent to a current value of said height above ground pointer.  
   
   
       13 . The radar altitude display as recited in  claim 10 , wherein said altitude ascent/descent trend tape projects from a current value of said height above ground pointer along an arc of the radar altitude display to a future height above ground value on said radar altitude scale.  
   
   
       14 . The radar altitude display as recited in  claim 13 , wherein said altitude ascent/descent trend tape projects from said current value of said height above ground pointer according to the following algorithm: Future altitude=Current value of radar altitude+(Rate of closure*Predictor Time Constant) 
 Where:    Rate of closure=moving average of value of radar altitude over a period of time; and    Predictor time constant=amount of time in the future to compute the radar altitude.    
   
   
       15 . The radar altitude display as recited in  claim 10 , wherein said altitude ascent/descent trend tape is color-coded.  
   
   
       16 . The radar altitude display as recited in  claim 10 , further comprising a pointer located at an end of said altitude ascent/descent trend tape.  
   
   
       17 . A method to facilitate flying a rotary wing aircraft in close proximity to the ground comprising the steps of: 
 (A) sampling a radar altitude;    (B) fusing the radar altitude into a combined output;    (C) displaying a current above ground level (AGL) altitude on an altitude display in response to the combined output; and    (D) displaying an altitude ascent/descent trend tape which represents a future altitude on the altitude display.    
   
   
       18 . A method as recited in  claim 17 , wherein said step (D) includes: 
 (a) displaying the current above ground level (AGL) with a pointer on the altitude display; and    (b) displaying the altitude ascent/descent trend tape along an arc of the altitude display where an origin of the altitude ascent/descent trend tape is the pointer.    
   
   
       19 . A method as recited in  claim 17 , wherein said step (D) includes: 
 (a) displaying the altitude display on a hover display.    
   
   
       20 . A method as recited in  claim 19 , further comprising the steps of: 
 (E) generating a heading drift symbology and a lateral drift symbology in response to the combined output which represents an aircraft heading drift and an aircraft lateral drift, respectively; and    (F) displaying the heading drift symbology and the lateral drift symbology on the hover display and displaying the heading drift symbology as a heading drift error bar which extends between an aircraft desired heading and an aircraft current heading.    
   
   
       20 . A method as recited in  claim 17 , wherein said step (A) includes: 
 (a) sampling the radar altitude during a degraded visual environment conditon.