Method and system for entering and displaying ground taxi instructions

[0001] The invention is generally related to systems and methods for tracking and planning vehicle movement, and specifically to airport map displays and to the entry and display of ground taxi routes.

[0002] As the air travel system becomes saturated, airports are becoming more and more congested. At the busiest airports, it is not uncommon to have 50 or more aircraft taxiing to and from multiple active runways using complex routes involving many different taxiways. System capacity is at or near saturation even during good weather conditions. Ground taxi can add over one hour to travel time for any particular flight. Efficient, flexible and adaptive ground operations are essential to enhancing air travel performance. This is especially true during poor weather conditions. As visibility drops, the number of aircraft that can operate at a given airport decreases rapidly and those aircraft still operating must slow down so as not to miss a turn or a hold short point, or taxi across an active runway without clearance.

[0003] A variety of methods are currently in use for aircrews to navigate on the ground. Most of these methods involve receiving verbal instructions from air traffic control, writing them down and interpreting those instructions by looking at a paper map of the airport. To effectively use such methods, the pilot must direct attention from outside the aircraft to inside the aircraft, and simultaneously transition from verbal instructions to a visual interpretation of those instructions while looking at a paper airport diagram. During low visibility, the aircrew loses their ability to use forward and peripheral vision because ground references and other airport traffic become harder to see, forcing the aircrew to concentrate their attention outside the aircraft to ensure safe operations. Recently, some devices have enabled aircrews to electronically display and orient the airport map and even show the aircraft position on the map; however, entry and display of taxi route information could be enhanced. The invention is directed to overcoming one or more of the problems or disadvantages associated with the prior art.

[0004] According to one aspect of the invention, a method of entering and displaying ground movement instructions for a vehicle may include loading an electronic database of map data into an onboard computer. Entry of ground movement instructions into the onboard computer may be made by entering a series of ground movement segments. Each ground movement segment may be automatically checked for continuity with a previous segment, a subsequent segment, an initial vehicle position or a vehicle destination. An electronic map showing an area of operation for the vehicle may be displayed. Vehicle position data may be acquired and displayed on the electronic map and updated according to vehicle movement. Ground movement segments may be graphically and/or alphanumerically displayed on the electronic map and updated according to vehicle movement.

[0005] According to another aspect of the invention, a system for the entry, recall and/or display of ground movement instructions for a vehicle may include an electronic entry device, an electronic output device, a computer, an electronic database and a position determining device. The computer may contain a software program which analyzes ground movement segments for continuity and ensures that each ground movement segment connects with adjacent segments, an initial vehicle position and/or a destination. The invention may facilitate the speed and accuracy of the entry of ground movement instructions. Alternatively, the system may store preloaded taxi routes for recall. These preloaded taxi routes may be constructed manually by the aircrew, or downloaded from air traffic control through a data link. This system may be simulated on a desktop computer for training purposes.

[0006] The system and method according to one aspect of the invention facilitate aircraft ground movement route entry through a user entered series of ground movement segments, and check each segment by ensuring each segment is continuous with the currently selected segment, an adjoining initial position and/or an adjoining destination. The system may separately display the segments that are continuous or otherwise join with the currently selected segment (the currently selected segment may be either the last entered segment or the last selected segment). Speed and accuracy of ground movement segment entry may be enhanced by allowing the pilot to quickly locate the next possible segments. An embodiment of the invention automatically pans and zooms the display as ground movement segments are entered to center on and fully show the last entered segment and its intersection with all possible next segments, thereby reducing the amount of manual panning and zooming that might otherwise be required.

[0007] The features, functions, and advantages can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments.

[0014] An embodiment of the invention may have at least two different entry interface options; menu and graphical. As will be discussed in further detail when referring to the figures, the menu interface option allows the user to make an entry by selecting a predisplayed softkey. Softkeys are selectable areas on the input/output display screen 124 (FIG. 4) that are available for activation by the user to make various inputs. The softkeys may be areas on the input/output display screen 124 which look like keys on a keyboard.

[0015] The graphical interface allows the user to make an entry by directly touching the segment on the map, or by placing a cursor on the segment, and confirming the selection by selecting the corresponding softkey generated by the computer with the cursor. As the user makes a selection, the system 20 automatically pans and zooms the display so as to fully display the last selected segment and its intersection(s) with any segment(s) that join the last selected segment. This prevents the user from having to pan and zoom the display manually to find the next segment. In addition, when the user makes a selection, the system 20 may automatically position the cursor in the menu or graphical interface in such a way as to facilitate the next selection by minimizing cursor movement to the next selection.

[0016] In the menu interface, the user selects segments from a set of softkeys, each of which represent an individual ground movement segment. The user may select the softkeys by either touching them, or placing the cursor over them and selecting the softkey with the cursor control device. The user has the option of selecting segments from a menu which may only display ground movement segments which join with the currently selected ground movement segment, an initial vehicle position and/or a vehicle destination. Alternatively, either the graphical or menu interface may be configured so as to allow creation and storage of taxi routes for recall. For example, Air Traffic Control may predefine a taxi route at an airport; the predefined taxi route may be stored in the system memory and recalled by the user, thereby accelerating the entry process.

[0017] Referring to FIG. 1, a system 20 is provided for entering and displaying ground taxi instructions including a computer 26 for the processing of data and generation of displays. One or more input/output devices 22 may be linked to the computer 26 and used to enter data for the computer 26. The input/output devices 22 may be combined into a single device such as, for example, a touchscreen. Alternatively, the input/output devices 22 may be separate, and/or one or both input/output devices 22 may be incorporated into existing aircraft displays. The input/output devices 22 may be any one of a cathode ray tube (CRT) display, a liquid crystal display (LCD), a head up display (HUD), plasma display, rear projection display, or any other suitable display device. Speech recognition and/or datalink may be used as input methods if desired.

[0018] An electronic map database 24 may be resident in a memory 25 of the computer 26 and may be updatable. The electronic map database 24 may contain multiple airport layouts including, but not limited to, runways, taxiways, terminal and other permanent structures, parking locations, and run-up locations. An example of one such a database is Jeppesen's Electronic Flight Bag Airport Map.

[0019] A vehicle position sensor 28 may be used to supply the computer 26 with vehicle position information. The vehicle position sensor may include one or more of, a Global Positioning System (GPS), an inertial navigation system (INS), a terrestrial based navigation system (such as VOR or TACAN), and/or a manually input starting or current position. The computer 26 may be configured to receive position data from any other aircraft system (i.e., the flight management computer, the autopilot, etc.).

[0020] A transmitter/receiver 30 for the wireless transmittal and receipt of data may be connected to the computer 26 for data transfer between the aircraft and external sources. This data may include taxi instructions from Air Traffic Control (ATC), position data, Notices to Airmen (NOTAMs), runway/taxiway information, weather information, delay information, information from a dispatcher and/or any other type of data suitable for wireless transmittal/receipt. A cursor control device 32, such as a keyboard, a mouse, a touchpad, a joystick, or any other device suitable for controlling a cursor may be connected to the computer 26.

[0021] FIG. 2 shows one embodiment of an implementation of displaying ground movement instructions and checking user input for accuracy. The first operation at 60 is to initialize the system 20. This may be done when the aircraft is powered up. The map database 24 may be loaded at 62 when needed, such as, for example, when the map database 24 changes or is improved. Once loaded, the map database 24 remains in the system 20 until updated or deleted. The system 20 keeps at least the last two versions of the map database 24 in memory, allowing the user to switch to a previous map database 24 should a current map database 24 become corrupt or unusable. This feature enables the user to load a new version of the map database 24 before it becomes active and switch the map database 24 at a changeover date.

[0022] The aircraft starting location may be determined at 64. This may be accomplished many different ways. For example, one or more of a Global Positioning System (GPS), an inertial navigation system (INS), a terrestrial based navigation system, retrieval from another aircraft system, such as a Flight Management Computer (FMC) and a manually input starting position may be used to determine the aircraft starting location.

[0023] The computer 26 generates the map display, as shown at 66, using the map database 24 and displays the map and the starting position, as shown at 68, on the input/output device 22. The system 20 determines the current gate or runway, and/or nearby gates and/or runways at 69 by analyzing the map database 24 for all gates and/or runways within a predefined distance of the aircraft starting location. Those gates and/or runways may be displayed for selection. At 70, the system 20 determines all segments that join the starting position. Alternatively, if the user selects a gate or runway as a starting point, the system 20 determines all segments that join the selected gate or runway as shown at 70. Segments that join the starting position may be determined by analyzing all segments for points in common with the starting position. The joining segments may be displayed separately, as shown at 72, on the input/output device 22 for user selection.

[0024] The user may select the next segment, as shown at 74, for example by touching the selection on the screen, or by positioning a cursor over the selection and activating it. The selected segment may be checked at 76 to ensure that it joins the previous segment and may be annunciated if the selected segment does not join the previous segment. The annunciation may be a visual, tactile and/or aural cue. The process may be repeated for the next segment, as shown at 78. If a selection is entered between two previously entered segments, the selected segment may be checked at 76 to ensure that it joins the previous and subsequent segments and may be annunciated if the selected segment does not join both adjacent segments. The system 20 monitors aircraft movement, as shown at 80, and may update the map display and taxi instructions to account for movement of the vehicle as indicated at 82.

[0025] FIG. 3 shows three of several possible positions of the input/output device 124, on an aircraft 120. The input/output display device 124 may be located in a cockpit 122 of the aircraft 120. Although this drawing shows that the input/output display device 124 may be mounted in any one or more of multiple locations on an instrument panel of the cockpit 122, the input/output display device 124 may be mounted in any one or more other locations within the cockpit 122 which are convenient for the pilots and where space is available. The input/output display device 124 may be incorporated into existing aircraft systems and displays; it may also include a stand-alone system.

[0026] FIG. 4 shows one embodiment of the input/output display device 124 operating in a menu interface mode. The input/output display device 124 displays a map (in FIG. 4, a map of O'Hare International Airport is shown), and also may simultaneously display a main menu 220 and sub-menus 222 as softkeys. At the top right of the display is a display scale 200. The scale may be displayed in nautical miles, kilometers, statute miles, or any other suitable unit of distance.

[0027] Working counterclockwise around FIG. 4, the main menu 220 provides Main menu softkeys 220a–e that may be activated by the user to select the type of segments for entry (i.e., Runways, Taxiways, Concourses, or Hold). A shaded softkey may represent an active selection as 220a shows. The pilot may make a selection in the menu mode in a plurality of ways, two of which are touching the softkey, with or without an instrument to facilitate the selection, or placing the cursor over a softkey and selecting it with the cursor control device 32. A Route softkey 220a on the Main menu 220 may select an intelligent entry feature on either the menu interface or the graphical interface. Selecting intelligent entry instructs the computer 26 to determine possible route segments that join the currently selected route; segment and display separately those possible route segments as individual softkeys on the map so that the user may select from those possibilities that join the currently selected route segment, starting position or destination. In the menu mode, segments that join the currently selected segment 224d may be displayed as softkeys 222a–f along the left side of the input/output display device 124 when the Route softkey 220a is selected.

[0028] When the Route softkey 220a is selected in the graphical mode, the segments that do not join the currently selected segment may be disabled for selection, allowing only the graphical selection of segments that join the currently selected segment. An alternative embodiment of intelligent entry in the graphical mode comprises highlighting all segments and/or displaying all associated softkeys for segments which join the currently selected segment. Another alternate embodiment comprises displaying a list of all segments that join the currently selected segment, similar to the menu interface, and selecting a segment for entry directly from the list. This may also be accomplished by graphically highlighting the map segment selected from the list and displaying the associated segment softkey in the map area near the segment.

[0029] Sub-menus 222 and sub-sub-menus 223 (FIG. 6), may be displayed when more information is needed. A small square on the taxiway sub-menu 222 softkey “H” 222a indicates that there is a sub-sub-menu available. Alternatively, an asterisk indicates a sub-sub-menu, containing a partial taxiway set, is available which displays only those ground movement segments which join the current segment. One instance in which sub-sub-menus may be employed is in the case of taxiway identifiers with subsets (H, H1, H2, etc.) 223a, 223b, 223c, or numerically identical runway identifiers With right, left, center, or any other alphanumerical designations. A Runways softkey 22c may display sub-menus for all runways for a given airport. A Taxiways softkey 22b may display sub-menus for all taxiways for a given airport. A Concourses softkey 220d may display sub-menus for all the gates and/or parking locations at a given airport.

[0030] Selecting the Hold softkey 220e allows the user to input at least one hold short instruction. Aircraft crossing of a hold short point may be annunciated. The annunciation may be a visual, tactile and/or aural cue.

[0031] A Route sub-menu 222 may show runways and taxiways available (222a, b, c, d, e) that connect with the currently selected ground movement segment. A Route display in the lower left-hand corner of the input/output display device 124 of FIG. 4 may show a taxi route as entered with a shaded softkey 224d showing the currently selected segment. The associated inverted triangle 224e shown above the top right corner of 224d indicates the insertion point for the next entry. The segment softkeys (224b, c, d) show what ground movement segments have been entered. A Route Action menu 226 in the lower left-hand corner of the screen allows the user to delete a segment 226a, clear the entire route 226b, or activate the current taxi route 226c. During taxi, route softkeys 224 in the activated route may show taxi progress through variable shading or highlighting of completed segments, the current segment, and upcoming segments.

[0032] In the lower right-hand corner of the input/output display device 124 is a View menu 227. A Center softkey 234 toggles a display center between ownship position and a center of the last selected segment or manual pan. A Zoom softkey 230 allows the user to change the scale of the displayed map. The system 20 may automatically declutter the symbology on the display by using an impingement algorithm. Each symbol may be assigned a location and an area on the screen, and as the scale decreases and symbol areas begin to overlap, the software program may selectively remove certain symbols based on a preprogrammed priority. This removes excess clutter and makes the display easier to read. The system 20 incorporates a manually activated simultaneous pan and zoom feature called local area zoom. When the user “double taps” the input/output display device, similar to double clicking the mouse on a desktop computer, the system 20 may automatically increase the magnification by a preset amount and center the magnified display on the point the user double tapped. The same local area zoom feature can be selected by placing the cursor at a point and tapping or otherwise activating the cursor control device twice rapidly in succession. In both touch and cursor implementations, a subsequent “double tap” restores the display center and scale to that which existed before the local area zoom was activated. A Pan softkey 228 allows the user to pan the display in the selected direction in order to see some map feature and/or more of the taxi route without zooming the map scale out to a larger scale.

[0033] As shown in FIGS. 4–6, the taxi route as entered may be graphically displayed on the airport map as a dashed line 236 while in the entry mode and this line may turn solid when the route is activated. The route line may be color coded consistent with Flight Deck design philosophy. Runways 238 and taxiways 240 may be displayed, the runways 238 may be outlined and have centerline stripes. An aircraft assigned or selected gate location 242 may be shown. An aircraft ownship position 244 may also be shown. Concourses 246, or any other logical grouping of gates and/or parking locations, may be shown and labeled with identifiers. The menu interface map display may be user selected as either north up, a static/fixed map with moving (rotating and translating) ownship position symbol 244, or heading up, a moving map (rotating and translating) with static/fixed ownship position symbol 244. Aircrew situational awareness may be enhanced by displaying the ownship position 244, the taxi route 236, and the airport map on the display 124. The cursor 237 may be symbolically represented as any appropriate symbol, such as, for example, a small cross on the screen, and may be controlled through the cursor control device 32.

[0034] FIG. 5 depicts a display of the input/output device 124 in the graphical interface mode. The graphical interface mode may have many of the same features as the menu interface mode. For example, the map portion of the display and the Zoom, Pan, Center and Route Action functions may be identical to that of the menu interface mode. The difference may be in the entry areas, for example. Instead of selecting a predisplayed softkey for entry, the user may directly select the gate, taxiway, or runway itself by touching it, or placing the cursor over it and selecting with the cursor control device 32. The graphical interface mode may include a softkey 248 for a selection entry/confirmation. The gate, taxiway or runway softkey may appear in close proximity to the selected gate, runway or taxiway on the map when the gate, taxiway or runway is selected by touch or cursor. In this case, the softkey 248 for runway 27R is displayed just to the north of runway 27R. The user makes the selection by touching the softkey or placing the cursor over the softkey and selecting with the cursor control device 32. In some cases, the computer may preposition the cursor to facilitate entry. One example may be when the Activate softkey 226c is selected, the cursor may be prepositioned on an Execute softkey to save the user from having to move the cursor to the Execute softkey. The graphical interface mode may be user selected as either north up, static/fixed map with moving (rotating and translating) ownship position symbol 244, or heading up, moving map (rotating and translating) with a static/fixed ownship position symbol 244.

[0035] In an alternate embodiment of the graphical interface entry, the route may be entered as a series of discrete sub-segments (i.e. short dashed lines or dots) collocated with the map segment. These sub-segments may appear/display when the route sub-segment is touched or the cursor is moved/passes over the sub-segment in the approximate direction of the overall segment. In this alternate embodiment, which may differ for touch or cursor interface, the segment identifier may be displayed in the alphanumeric route line once some predetermined number of sub-segments are graphically displayed or selected. Sub-segments may be removed from the display by deleting the segment identifier from the alphanumeric route line, or by touching or passing the cursor over the displayed sub-segment.

[0036] Logical filtering and sub-segment display thresholds may be implemented to prevent unwanted nuisance display of, or deletion of sub-segments the cursor may pass over or which may be inadvertently touched. Selection of the displayed sub-segment and/or entry of the associated identifier in the alphanumeric route line may require positive confirmation such as, for example, cursor select switch activation. This alternate embodiment of graphical interface route entry may be facilitated by logic which automatically connects displayed sub-segments of joined segments. Thus a least one sub-segment per segment may be entered. Automatic connection of sub-segments eliminates the need for the user to connect sub-segments in adjacent segments which join one another, thus speeding up route entry.

[0037] FIG. 6 is a display of the menu mode showing the display of the sub-sub-menus 223 on the left side of the screen. The sub-sub menus 223 may appear if needed and may stay displayed until the user makes a selection.

[0038] Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed herein and in the accompanying claims. For example, other embodiments may include systems and methods according to the invention for use in connection with vehicles other than aircraft, such as automobiles, ships, mining vehicles, agricultural equipment, construction equipment, or any other vehicle capable of movement on, above, or below the surface of the earth.