Abstract:
A vertical deviation indicator and predictor includes a vertical deviation scale having a plurality of vertically spaced markers, one of the markers indicating the vehicle&#39;s present vertical position. Current vertical flight path segment symbols are selectively superimposable over the vertical deviation scale in accordance with the vehicle&#39;s current vertical flight path segment. Next vertical flight path segment symbols are selectively superimposable over the vertical deviation scale in accordance with the vehicle&#39;s next vertical flight path segment, the position thereof being determined by backward extrapolation of the next vertical flight path segment. Thus, the type and position of the current and next vertical flight path segment symbols on the vertical deviation scale provide situational awareness of the present vertical flight path deviation and an indication of an efficient and timely manner for intercepting the desired flight path.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to aircraft instrumentation displays and more particularly to a vertical deviation indication and prediction system for providing situational awareness of the present vertical flight path and an efficient indication of a manner for intercepting the desired flight path. 
   2. Description of the Related Art 
   The depiction of lateral navigation (LNAV) information in the flight deck has matured significantly over recent years. It is fairly easy for pilots to visualize their position on the active (FMS) flight plan, understand where the next waypoint occurs, the direction of the next leg, and visualize any offsets when deviating. Furthermore, when navigating by heading/track, it is also a straightforward matter to manually create an intercept path to rejoin the flight plan. 
   The same cannot be said for Vertical Navigation (VNAV). One of the principal reasons that pilots become confused when using VNAV is that they do not have a comprehensive visualization tool for the vertical flight plan. Recent designs by air transport aircraft manufacturers have implemented vertical situation displays. However, many smaller/older aircraft do not possess anything more than simple vertical deviation indicators that show the current deviation from the vertical flight plan. No information is provided about the next vertical flight plan segment beyond the next flight plan waypoint. 
   An example, of a Vertical Situation Display (VSD) for use with Boeing aircraft is described in the article entitled, “Vertical Situation Display for Improved Flight Safety and Reduced Operating Costs”,  Aero , No. 20, October 2002, pages 3–11. The Boeing VSD works in conjunction with the terrain-mapping feature of the terrain awareness and warning system (TAWS), a Honeywell enhanced ground proximity warning system. It provides an intuitive presentation of the vertical situation relative to the surrounding terrain and the final approach decent path. In addition to terrain alerting, the TAWS provides a lateral, or top-down, view of terrain. The VSD depicts a profile, or side view, of terrain and flight path data. 
   U.S. Pat. No. 6,720,891, issued to Chen et al., entitled, “Vertical Situation Display Terrain/Waypoint Swath, Range to Target Speed, and Blended Airplane Reference” discloses a flight information display for the flight deck of an aircraft showing a pictorial side view of the flight path or the area directly in front of the aircraft area having a selected distance of at least 0.5 nautical miles, comprising (a) a pictorial representation to scale of the profile of the highest elevations of a swath of terrain along said path or area, (b) an icon positioned on the left or right side of the display representing the aircraft, the altitude of which is to scale with the height of the terrain, and (c) an altitude reference scale; wherein the width of the swath is at least 0.1 nautical miles and no greater than the distance of the minimum accuracy of the means for determining the aircraft&#39;s location. 
   U.S. Pat. No. 5,936,552, issued to Wichgers et al., entitled, “Integrated Horizontal and Profile Terrain Display Format For Situational Awareness”, discloses a visual display format for a terrain situational awareness system comprising a horizontal terrain elevation view and a profile terrain elevation view of potential terrain hazards integrated onto a single display. 
   U.S. Pat. No. 6,154,151, issued to Wichgers et al., entitled, “Integrated Vertical Situation Display for Aircraft”, discloses an integrated vertical situation display (IVSD) for an aircraft, and method of displaying vertical situation information. The IVSD includes an electronic display for displaying the vertical situation of the aircraft, input interfaces for receiving vertical profile information signals, and a processing circuit for reading the information signals and generating display signals applied to the display therefrom. The display has a vertical profile view area to display the vertical situation in front of, above, and below the aircraft. The information sources may include a flight management system, traffic alert and collision avoidance system (TCAS) and a ground proximity warning system. Vertical situations are displayed by visual indicia representing, for example, aircraft position, path angle, flight path, waypoints, TCAS targets, altitude preselect, decision height, runway, ground contour, and vertical speed. The integrated display minimizes the cognitive workload of the operator in assessing the total vertical situation. 
   U.S. Pat. No. 6,154,151, issued to Barber et al., entitled, “Enhanced Vertical Terrain Profile Display”, discloses a flight display for use in an avionics system that has a visual display format to show an enhanced vertical situation of an aircraft. Included is a vertical terrain profile display that displays terrain in front of the aircraft over a selected range and a selected swathe width. The vertical terrain profile display shows a side-on terrain profile view with a digital display of the selected swathe width and a display of range in front of the aircraft. A plan view of the aircraft position is included that shows swathe lines on either side of an aircraft to show the selected swathe width. A means for selecting the swathe width by the pilot is provided. The vertical terrain profile display may be changed into a end-on vertical terrain profile view over the selected swathe width. The end-on terrain profile view has a digital display of the selected range and a digital display of the selected swathe width on each side of the aircraft. 
   As will be disclosed below, the present invention affords a simple method and symbology for providing the pilot with much improved situational awareness, regarding the position of the airplane relative to the current vertical flight plan segment, and the position relative to an extension (rearwards extrapolation) of the next vertical flight plan segment. 
   SUMMARY OF THE INVENTION 
   In a broad aspect, the present invention is a vertical deviation indication and prediction system for vertical navigation situational awareness of a vehicle. The vertical deviation indication and prediction system includes a vertical deviation indicator and predictor that includes a vertical deviation scale having a plurality of vertically spaced markers, one of the markers indicating the vehicle&#39;s present vertical position. A plurality of current vertical flight path segment symbols are selectively superimposable over the vertical deviation scale in accordance with the vehicle&#39;s current vertical flight path segment. A plurality of next vertical flight path segment symbols are selectively superimposable over the vertical deviation scale in accordance with the vehicle&#39;s next vertical flight path segment, the position thereof being determined by backward extrapolation of the next vertical flight path segment. Thus, the type and position of the current and next vertical flight path segment symbols on the vertical deviation scale provide situational awareness of the present vertical flight path deviation and an indication of an efficient and timely manner for intercepting the desired flight path. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  illustrates the vertical deviation indicator and predictor of the vertical deviation and indication system of the present invention and a legend showing the symbology used therefor at a first airplane position. 
       FIG. 1B  illustrates a vertical flight profile viewer of the vertical deviation and indication system, illustrating the flight profile corresponding to the vertical deviation indicator and predictor of the  FIG. 1A  example. 
       FIG. 2A  illustrates the vertical deviation indicator and predictor of the vertical deviation and indication system of the present invention and a legend showing the symbology used therefor at a second airplane position. 
       FIG. 2B  illustrates a vertical flight profile viewer of the vertical deviation and indication system, illustrating the flight profile corresponding to the vertical deviation indicator and predictor of the  FIG. 2A  example. 
       FIG. 3A  illustrates the vertical deviation indicator and predictor of the vertical deviation and indication system of the present invention and a legend showing the symbology used therefor at a third airplane position. 
       FIG. 3B  illustrates a vertical flight profile viewer of the vertical deviation and indication system, illustrating the flight profile corresponding to the vertical deviation indicator and predictor of the  FIG. 3A  example. 
     FIGS.  4 A–B through  13 A–B provide examples of the use of the present invention at other airplane positions. 
       FIG. 14  is an illustration of a flight deck display system incorporating the vertical deviation indicator and predictor of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings and the characters of reference marked thereon,  FIG. 1A  illustrates a preferred embodiment of the vertical deviation indicator and predictor of the present invention, designated generally as  10 . The vertical deviation indicator and predictor  10  provides information regarding the following questions: 
   1) Where is my current VNAV flight plan segment relative to me? 
   2) Is my current VNAV flight plan segment level, climbing, or descending? 
   3) Where is my next VNAV flight plan segment relative to me? 
   4) Is my next VNAV flight plan segment level, climbing, or descending? 
   To accomplish the above, a vertical deviation scale  12  is used that has a plurality of vertically spaced markers  14 . Preferably, a centrally positioned marker  14 ′ is utilized to indicate the vehicle&#39;s present vertical position. The symbology shown in  FIG. 1A  is preferably utilized. These symbols are superimposable over the vertical deviation scale  12 . The filled diamonds depict the relative position of the current VNAV flight plan segment to the airplane. These filled diamonds may be of a desired color such as magenta. (This color convention emphasizes that the VNAV path is FMS derived.) The presence (or absence) of the (upward or downward) trend line indicates whether the segment is level, climbing, or descending. 
   Similarly, the non-filled diamonds depict the relative position of the “extension” of the next VNAV flight plan segment relative to the airplane. This “extension” will only be extrapolated backwards to the FROM waypoint. In other words, if the TO waypoint is waypoint “N”, the next VNAV flight plan segment (after the TO waypoint) will be extrapolated backwards to waypoint “N−1”. These non-filled diamonds may be of a desired color, such as green. Although the use of diamonds has been shown, it is understood that other symbols could easily be utilized such as stars. 
   As will be discussed in greater detail below, situations indicative of a potential need for corrective action by the pilot are indicated when the airplane (center of the deviation scale) is not located between the current segment and next segment VNAV deviation symbols. 
   Generally, the indicator and predictor  10  shown in  FIG. 1A  is used in aircraft that do not possess a vertical flight profile viewer. The primary basis of the invention was to provide VNAV path awareness for airplanes that do not have the luxury of the vertical flight profile viewer. However, if desired a vertical indication and prediction system of an aircraft may include a vertical deviation indicator and predictor  10  in conjunction with a vertical flight profile viewer, designated generally as  16 , in  FIG. 1B . The vertical flight profile viewer  16  includes a graphical representation of the desired vertical flight path of the vehicle; and a graphical representation of backward extrapolations (in hatched lines) of each of the desired vertical flight path segments. 
   In the  FIGS. 1A ,  1 B depiction, the airplane is climbing out after takeoff. The current VNAV flight plan segment  18  is above the airplane, and climbing. The next segment  20  is level, and the extension  22  of this segment is also above the airplane. If the airplane flies level, or continues to climb at a slower rate than the VNAV segment  18 , the airplane will not intercept the segment  18  before the next waypoint  24 . This is easily interpreted by the airplane (center  14 ′ of the deviation scale) not being between the two VNAV deviation symbols  26 ,  28 . 
   Referring now to  FIGS. 2A and 2B , the airplane has leveled off below the current VNAV segment  20 . The indicator (i.e. symbol  30 ) shows that the current segment  20  is level. The extension  32  of the next segment  34  is currently below the airplane, and is climbing. If the airplane continues flying level, it will intercept the next segment extension  32 . This will be indicated by the airplane being between the two deviation symbols  30 ,  36 , and the diamond symbol  36  slowly rising towards the airplane. When the airplane intercepts the next segment extension  32 , as long as it can climb at the same rate as the extension, it will be able to meet any constraints at the next waypoint  38  and not have to adjust the climb rate as it passes through the next waypoint. In other words, being able to intercept the next segment extension allows the airplane to set up a climb (or descent) profile that will not require significant changes as the airplane passes through the TO waypoint. 
   Referring now to  FIGS. 3A and 3B , the airplane has leveled off above the current VNAV segment  20 . The indicator (i.e. symbol  40 ) shows that the current segment is level. The extension  32  of the next segment is also below the airplane, and climbing. If the airplane continues flying level, it will not intercept the current segment  20 , or next segment extension  32 , before reaching the next waypoint  38 . This is indicated by the airplane being above the two deviation symbols  40 ,  42 , and the diamond symbol  42  slowly rising towards the current segment  20 . At the next waypoint  38 , the two symbols will intercept (overlay) below the airplane. 
   Referring now to  FIGS. 4A and 4B , the airplane is level and below the current flight plan segment  20 , and has also passed the next segment extension  32 . Both symbols  44 ,  46  will now be above the airplane on the deviation indicator  10 . With the next segment climbing away above the airplane, it is unlikely that the airplane will be able to cross the next waypoint at the required altitude. 
   Referring now to  FIGS. 5A and 5B , continuing from the previous figure, the airplane has now passed the waypoint  38 , and is below the current segment  34 . This segment  34  is now climbing away, with the next segment  48  level and above the airplane. If the airplane does not initiate a climb, and bring the diamond  50  down towards the center of the deviation display  10 , it will not arrive at the next waypoint at the flight plan altitude, 
   In the situation of  FIG. 6A–B , the airplane has climbed above the current vertical flight plan segment  34 . The deviation indicator  10  shows that the current segment  34  is below the airplane, and climbing, while the next segment  48  is above the airplane and level. If the airplane maintains a level altitude, the diamond  52  will climb to the center of the display  10 , indicating the interception of the flight plan profile. If the airplane continues to climb, the non-filled diamond  54  will eventually descend to the center of the deviation display  10 , at which point the airplane can level out and arrive at the next waypoint at the correct altitude. 
   Referring now to  FIGS. 7A–7B , the airplane is below the current segment  48  altitude. The extension  56  of the next segment  58  is above the airplane, and it will involve a path descent. This is indicated by the symbol  60  with the down-facing trend arrow. If it continues flying level, the airplane will not arrive at the next waypoint  62  at the planned altitude. 
   Referring now to  FIGS. 8A–8B , the airplane is above the current vertical flight plan segment  48 , with the next segment extension  56  above the airplane, and descending. If the airplane descends, it will be able to intercept the current segment, and proceed to the next waypoint at the requested altitude. If it continues to fly level, it will be able to intercept the extension  56  of the next segment  58  (filled diamond  62  will descend to the center of the deviation scale), and then start the path descent to arrive at the correct altitude at the next waypoint. 
   In the position of  FIG. 9A–B , the airplane finds itself below the current descent segment (path)  58 , with the next segment  64  below the airplane and level. If the airplane continues to fly level, it will intercept the descending path, as shown by the filled diamond  66  moving towards the center of the deviation display. Alternatively, the airplane could descend faster than required to intercept the extension of the next segment  64 . In this case, the non-filled diamond  68  would gradually climb towards the center of the deviation display. 
   Referring now to  FIG. 10A–B , the airplane is above the current flight plan altitude, and above the extension  56  of the next (descending) segment  58 . Both deviation indicators  70 ,  72  are positioned below the center of the display; with the next segment extension  56  continuing to move lower. In this situation, the airplane will not intercept either the current path, or next segment extension  56 , before reaching the next waypoint. 
   Referring now to  FIG. 11A–B , continuing from the previous figure, the airplane has now passed the waypoint  62 . The current segment (path)  58  is still below the airplane, and descending, with the next segment  64  also below the airplane, and level. If the airplane does not initiate a rapid descent, it will not be able to reach the next waypoint  74  at the required altitude. The symbols  76 ,  78  illustrate this situation. 
   Following from the previous figures, the airplane was not able to cross the waypoint at the required altitude. Referring now to  FIG. 12A–B  the airplane is above the current flight plan altitude  64 , but below the extension  80  of the next path segment  82 . With the non-filled diamond  84  currently above the airplane, and moving towards the center, it is still possible for the airplane to intercept the extension  80  of the next path segment  82 , and follow it down to cross the next waypoint  84  at the correct altitude. 
   The final example illustrated by  FIGS. 13A–13B  shows the airplane below the current (level) path segment. The airplane could either climb, to intercept the current flight plan altitude, or remain in level flight beyond the next waypoint  84 , to intercept the final path descent towards the airport. 
   The present invention is particularly suitable for retrofitting to existing displays (vertical deviation indicator) or for relatively low cost business/regional applications. It may serve as a forward-fit display function for systems that do not have the vertical flight profile viewer. 
   The aircraft Flight Management System (FMS) provides source data for the vertical deviation indicator and predictor. Such source data includes flight plan waypoints, and the calculated or constrained crossing altitudes. The software application, which can reside within or outside the FMS, can then use this data to display the vertical deviation scale. 
   Referring now to  FIG. 14 , a vertical deviation indicator and predictor  10  of the present invention is shown as how it may be integrated into a flight deck display system, designated generally as  86 . In this example, the indicator and predictor  10  is shown to the right of an attitude sky/ground ball  88 . The indicator and predictor are shown as diamonds. 
   Other embodiments and configurations may be devised without departing from the spirit of the invention and the scope of the appended claims.