Vertical situation display terrain/waypoint swath, range to target speed, and blended airplane reference

#In modern flight decks, the primary flight information display (PFD) and the navigation display (ND) are the key displays available for providing situational awareness to the pilot. Although the primary flight information display provides aircraft attitude and performance information through the attitude direction indicator (ADI), airspeed tape, heading and track indicator, and vertical speed indicator (VSI), the performance information is not shown in relation to the aircraft's surroundings. The navigation display provides fairly complete horizontal situational awareness with a top down (map) view of the aircraft and its surroundings. The navigation display tries to address vertical situational awareness through a vertical path deviation indicator, waypoint altitude constraint information, a range to altitude arc, and a selectable terrain picture from a Terrain Awareness and Warning Systems (TAWS). TAWS provides a contour map of surrounding terrain. Due to the display shading limitations and the nature of a top down view display, the contour map can only provide a general awareness of the surrounding terrain height. Also, to avoid pilot complacency and possible false alarms on takeoff and landing, some systems may have a “blackout” elevation below which the display provides no terrain information in normal conditions. Even with these vertical situational awareness features on the navigation display, the information still requires some interpretation, and approach and landing accidents continue to occur. This leaves the pilot with TAWS to provide both horizontal and vertical situational awareness of terrain. The pilot may not be able to perform an optimal vertical maneuver if the pilot is not aware of the height of the surrounding terrain. For flight deck displays that show the terrain directly in front of the aircraft, the input for this type of device may be a database of topography information that generates a display based on position information from the aircraft's navigational equipment. However, the display changes with slight adjustments to the direction of the aircraft, making it appear “noisy”. Also, navigational instruments for determining the exact position of an aircraft usually have some degree of error. For example, if the aircraft's automated navigational equipment is only accurate to within 10 nautical miles of the exact location of the aircraft, and the topography display only shows a “line” of topography directly in front of where the aircraft instruments indicate the aircraft is located, the topography display will be not be accurate as to the topography directly in front of the aircraft if the aircraft's exact position is actually 9.5 nautical miles from the location indicated by the navigation equipment. A presentation of terrain and waypoints along the current track of the aircraft provides some awareness, but during turns the pilot will not see terrain in the projected path of the turn.

#To assist pilots with final approach and landing, a localizer and a glideslope indicator may be provided on the electronic attitude director indicator to give the pilot information as to how much the aircraft is deviating from the ideal landing approach angle, as defined by a radio signal from the runway. When the aircraft is not on this ideal path, the flight deck instruments do not indicate the degree of correction required to return the aircraft to the correct descent path. If the pilot under- or overcorrects the descent angle and cannot position the aircraft onto a suitable landing approach path in a short period of time, the pilot may have to make a decision to abort the landing, circle, and begin another landing approach. A system that gives the pilot better information about the current relationship between the aircraft and the ideal descent and landing approach path will aid the pilot.

#At various times during ascent and descent of an aircraft, it may be necessary for the aircraft to reach a target speed by the time the aircraft reaches a particular geographic point. The airspeed tape on the primary flight information display indicates current and selected airspeeds, but the pilot has to judge how long it will take to achieve the selected airspeed. The pilot then needs to calculate how far the aircraft will travel before the target speed is achieved. These calculations and estimations may not be very precise and may distract the pilot from performing other duties connected with flying the aircraft and maintaining an accurate mental picture of the situation.

#The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings.

#FIG. 1 illustrates one embodiment of a Vertical Profile Display providing a view of the vertical terrain along the track of the aircraft.

#FIG. 2 is a schematic of one embodiment of a terrain swath used to generate the vertical profile display.

#The flight information display of the first aspect of the invention specifies a region in front of the aircraft to show terrain, waypoints and runways, on a vertical profile display. The source of the information to generate the profile of the terrain display may come from, but is not limited to, an on-board computer having a database of topographical information or a ground mapping radar. A Vertical Profile Display (VPD), provides a view of the vertical plane along the track of the aircraft (see FIG. 1), and may also display other information such as data on aircraft performance or target altitude information.

#The terrain depicted on the display is the highest terrain that is within a specified swath of terrain along the direction of the airplane's track. Specifically, the terrain value depicted at any given distance from the airplane symbol is the maximum terrain height along an arc at that given distance centered on the airplane and bounded by the edges of the swath. The swath may be of any suitable width or shape, but preferably widens as the distance from the airplane increases to take into account any slight variations from a straight-line trajectory in the path of the airplane. Most preferably, the swath is approximately the shape of a triangle with a corner at the nose of the airplane. In one embodiment, the projected swath also includes terrain in the direction of a turn because the swath preferably widens in the direction of any turns. In this embodiment, an algorithm calculates the swath to be projected and bases the width of the most distant part on the swath by the sensed crosstrack acceleration.

#The width of the terrain used for input to generate the display is preferably at least about 0.15 nautical miles (nm), more preferably at least 0.30 nm. The width is also preferably at least the resolution of the terrain database, most preferably at least the required navigation performance (RNP) for the current phase of flight or landing approach; but preferably no greater than 3 times the RNP for that phase of flight or approach, and more preferably no greater than 2 times the RNP for that phase of flight or approach. The distance in front of the aircraft depicted in the display is preferably at least 0.5 nm. If the flight deck also contains on a separate top-down display of terrain in front of the airplane to the compass rose the distance depicted on the side-view display preferably at least half the range that is shown on the top-down display of terrain in front of the airplane to the compass rose; but is preferably no greater than 2 times the range. Most preferably, the display's range is the same as the range that is shown on the map in front of the airplane to the compass rose.