Abstract:
An airborne processor is linked to a ground-based, vehicle based, or satellite-based supplier of approaching aircraft data and/or terrain data, including airfield structures. The processor also has access to the aircraft&#39;s state, e.g. position, speed, intended route, aircraft dimensional data, or the like. Algorithms within the processor calculate a zone of protection about the aircraft in light of aircraft type, turning radius, and other identifying data. The processor combines the present and estimated future positions of the aircraft with the approaching aircraft and/or airfield structure data, and creates an alert to the crew if a threat of a ground incursion is detected. The display provides a visual of the zone of protection about the aircraft, and approaching aircraft and/or airfield structure to draw the attention of the crew to the threat.

Description:
TECHNICAL FIELD 
     The present invention relates to a display for a vehicle, and more particularly to a system and method for displaying a zone of protection associated with an aircraft while maneuvering on ground. 
     BACKGROUND OF THE INVENTION 
     Situational awareness is of utmost importance when operating a vehicle, such as an aircraft. Aircraft crew typically have a very limited awareness of their aircraft&#39;s dimensions and virtually no awareness of the proximity of the aircraft&#39;s wingtips and tail in relationship to other aircraft and airfield structures during ground maneuvers, such as in holding areas, near gate ramps, and near airport buildings. This compromise in situational awareness during ground maneuvers can increase the likelihood of ground incursions. Ground incursions between aircraft and airfield structures, or other aircraft, can be relatively expensive and potentially hazardous for the aircraft owners, operators and airport authorities. For example, aircraft are currently able to broadcast their position, altitude, and other related information through ADS-B. This information can be received by other aircraft within a 100 NM (nautical mile) radius, including aircraft performing ground maneuvers. Aircraft within that vicinity can pick up the information and can then display it on their cockpit displays. While this type of information is useful for preventing some aircraft incursions during runway ground maneuvers, interpreting the information received from such broadcast while maneuvering the aircraft in very tight, congested areas, such as holding areas and gate ramps, is more difficult. 
     Modern aircraft displays can provide a visual presentation of information in both a graphical display and a textual display. Displays used in aircraft, and particularly those used in aircraft for flight planning and monitoring, are capable of displaying a considerable amount of information such as flight plan information, terrain information, airborne weather data ADS-B data, obstacle data, traffic sensor data or Traffic alert and Collision Avoidance System (TCAS) data, relative terrain data and Enhanced Ground Proximity Warning System (EGPWS) data. The displayed information is crucial to aircraft operation, and can provide situational awareness to the pilot when the aircraft is in the air, or on the ground. 
     The display of aircraft information to curtail incursions between two or more aircraft or between an aircraft and an airport structure is of great importance. Hence, there is a need for a display system and method that displays, in real-time, a zone of protection associated with aircraft during ground maneuvers. The display of this type of information would reduce the workload on the flight crew during taxi, and maneuver about gate ramps, in holding areas and near airfield structures, and/or reduce the probability of an aircraft incursion occurring during these ground maneuvers. The present invention addresses one or more of these needs. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a display system and method that displays, in real-time, a zone of protection associated with an aircraft during ground maneuver. 
     In one embodiment, and by way of example only, a flight deck display system includes a processor and a display device. The processor is adapted to receive data representative of an aircraft during a ground maneuver, and operable in response thereto to determine a zone of protection associated with an aircraft and supply one or more image rendering display commands. The display device is coupled to receive the image rendering display commands and is operable, in response thereto, to render an image representative of the zone of protection. 
     In another exemplary embodiment, a method of displaying a zone of protection during a ground maneuver on an aircraft flight deck display system includes the steps of obtaining real-time vehicle ownship data and at least one of real-time additional vehicle data and airfield structure data. The method further includes determining a zone of protection associated with the vehicle ownship, and a zone of protection associated with at least one of the additional vehicle and the airfield structure, and displaying an image representative of the determined zones of protection on the aircraft flight deck display system. Algorithms within the computer combine the data representative of the present and estimated future positions of the aircraft with the approaching aircraft and/or airfield structure data, and create an alert to the crew if a threat is detected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will hereinafter be described in conjunction with the appended drawing figures, wherein like numerals denote like elements, and: 
         FIG. 1 . is a functional block diagram of an integrated flight display system usable with the instant invention; 
         FIG. 2 . is a functional block diagram of a stand-alone computer display system usable with the instant invention; 
         FIG. 3  is a simplified representation of an exemplary display screen that may be used in the system of  FIG. 1 , which shows the overall layout of the display screen, and on which various images may be simultaneously displayed; 
         FIG. 4  is an exemplary display screen that depicts a lateral situation view of an aircraft&#39;s zone of protection in accordance with the instant invention; 
         FIGS. 5-7  are exemplary display screens that depict lateral situation views of an aircraft&#39;s zone of protection relative to the zone of protection of an approaching aircraft in accordance with the instant invention; 
         FIG. 8  is an exemplary display screen that depicts a lateral situation view of a multi-zonal zone of protection for an aircraft in accordance with the instant invention; 
         FIGS. 9-10  are exemplary display screens that depict a holding pad showing multiple aircraft protection zones in accordance with the instant invention; and 
         FIG. 11  is a flow chart and schematic of an algorithm that may be used in practicing the instant invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
     The present invention may be described in terms of functional block diagrams and various processing steps. It should be appreciated that such functional blocks may be realized in many different forms of hardware, firmware, and/or software components configured to perform the various functions. For example, the present invention may employ various integrated circuit components, e.g., memory elements, digital signal processing element, look-up tables, and the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices. Such general techniques are known to those skilled in the art and are not described in detail herein. Moreover, it should be understood that the exemplary process illustrated may include additional or fewer steps or may be performed in the context of a larger processing scheme. Furthermore, the various methods presented in the drawing Figures or the specification are not to be construed as limiting the order in which the individual processing steps may be performed. It should be appreciated that the particular implementations shown and described herein are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the invention in any way. 
     Turning now to the description, and with reference to  FIG. 1 , an exemplary flight deck display system will be described. The system  100  includes at least a user interface  102 , a processor  104 , an aircraft identification database  101 , one or more navigation databases  106 , a navigation computer  108 , a plurality of sensors  110 , and a display device  112 . The plurality of sensors  110  may include inertial sensors or a GPS (Global Positioning System) that is capable of providing several of the described inputs, such as aircraft speed, position, and altitude. The user interface  102  is in operable communication with the processor  104  and is configured to receive input from a user  109  (e.g., a pilot) and, in response to the user input, supply command signals to the processor  104 . The user interface  102  may be any one, or combination, of various known user interface devices including, but not limited to, a cursor control device (CCD), such as a mouse, a trackball, or joystick, and/or a keyboard, one or more buttons, switches, or knobs. In the depicted embodiment, the user interface  102  includes a CCD  107  and a keyboard  111 . The user  109  uses the CCD  107  to, among other things, move a cursor symbol on the display screen, and may use the keyboard  111  to, among other things, input various data. 
     The processor  104  is in operable communication with the navigation computer  108 , the aircraft identification database  107 , the sensors  110 , and the display device  112  via, for example, a communication bus  114 . The processor  104  is coupled to receive various types of data from the navigation computer  108 , aircraft identification database  107 , and the sensors  110  and may additionally receive navigation data from one or more of the navigation databases  106 , and is operable to supply appropriate display commands to the display device  112  that cause the display device  112  to render various images. Though not shown in  FIG. 1 , it will be appreciated that the processor  104  may additionally be coupled to receive various data from one or more other external systems. For example, the processor  104  may also be in operable communication with a source of weather data, a terrain avoidance and warning system (TAWS), an ADS-B system, a traffic and collision avoidance system (TCAS), an instrument landing system (ILS), and a runway awareness and advisory system (RAAS), just to name a few. If the processor  104  is in operable communication with one or more of these external systems, it will be appreciated that the processor  104  is additionally configured to supply appropriate display commands to the display device  112  so that the data supplied from these external systems may also be selectively displayed on the display device  112 . 
     A number of aspects of display element  112  (which are controlled by processor  104  in a practical embodiment) may contribute to the improved contents and appearance of the display, thus increasing the situational and terrain awareness of the pilot and/or flight crew. The image generation and display aspects may leverage known techniques such that existing display systems can be modified in a straightforward manner to support the different features described herein. In a practical implementation, the concepts described herein may be realized in the form of revised display generation software or processing resident at processor  104 . 
     Processor  104  typically encompasses one or more functional blocks used to provide flight management, navigational, weather, terrain, and positional interface with the pilot, and input to display element  112 . Processor  104  may include or cooperate with a mode, position and/or detection element that is capable of determining the mode or position of the vehicle relative to one or more reference locations, points, planes, or navigation aids. In addition, processor  104  may be configured to receive, analyze, condition, and process navigation and positional information, including flight path information as well as ground positional information associated with the vehicle. In this regard, processor  104  may include any number of individual microprocessors, flight computers, navigation equipment, memories, storage devices, interface cards, and other standard components known in the art. Moreover, processor  104  may include any number of microprocessor elements, memory elements, power supplies, and other functional components as necessary to support the operation of the display system  100 . In this respect, processor  104  may include or cooperate with any number of software programs or instructions designed to carry out various methods, process tasks, calculations, control functions, and the generation of display signals and other data used by display element or monitor  112 . For example, processor  104  may be configured to generate an annunciator associated with the position of the aircraft relative to at least one reference location or surrounding aircraft, to generate windows corresponding to user inputs, to combine inputs from the sensors  110  to create a data stream for presentation to the display element  112 , and the like. 
     In the depicted embodiment, the processor  104  includes on-board RAM (random access memory)  103 , and on-board ROM (read only memory)  105 . The program instructions that control the processor  104  may be stored in either or both the RAM  103  and the ROM  105 . For example, the operating system software may be stored in the ROM  105 , whereas various operating mode software routines and various operational parameters maybe stored in the RAM  103 . It will be appreciated that this is merely exemplary of one scheme for storing operating system software and software routines, and that various other storage schemes may be implemented. It will also be appreciated that the processor  104  may be implemented using various other circuits, not just one or more programmable processors. For example, digital logic circuits and analog signal processing circuits could also be used. 
     The navigation databases  106  include various types of navigation-related data. These navigation-related data include various flight plan related data such as, for example, waypoints, distances between waypoints, headings between waypoints, navigational aids, obstructions, special use airspace, political boundaries, communication frequencies, aircraft departure and approach information, protected airspace data, and data related to different airports including, for example, runway-related data. It will be appreciated that, although the navigation databases  106  are, for clarity and convenience, shown as being stored separate from the processor  104 , all or portions of these databases  106  could be loaded into the on-board RAM  103 , or integrally formed as part of the processor  104 , and/or RAM  103 , and/or ROM  105 . The navigation databases  106 , or data forming portions thereof, could also be part of one or more devices or systems that are physically separate from the display system  100 . 
     The aircraft identification database  101  includes various types of identification-related data. These aircraft identification-related data include aircraft structural dimensions for ownship and other aircraft. These dimensions are public data available from the FAA type certification office. The dimensional data allows the display system  100  to scale the size of the aircraft and to generate the zone of protection having appropriately sized dimensions. It will be appreciated that, although the aircraft identification database  105  is, for clarity and convenience, shown as being stored separate from the processor  104 , all or portions of these database  101  could be loaded into the on-board RAM  103 , or integrally formed as part of the processor  104 , and/or RAM  103 , and/or ROM  105 . The aircraft identification database  101  could also be part of one or more devices or systems that are physically separate from the display system  100 . 
     The navigation computer  108  is in operable communication, via the communication bus  114 , with various data sources including, for example, the navigation databases  106 . The navigation computer  108  is used, among other things, to allow the pilot  109  to program a flight plan from one destination to another, and to input various other types of flight-related data. The flight plan data may then be supplied, via the communication bus  114 , to the processor  104  and, in some embodiments, to a non-illustrated flight director. In the depicted embodiment, the navigation computer  108  is additionally configured to supply, via the communication bus  114 , data representative of the current flight path and the aircraft category to the processor  104 . In this regard, the navigation computer  108  receives various types of data representative of the current aircraft state such as, for example, aircraft speed, altitude, and heading. The navigation computer  108  supplies the programmed flight plan data, the current flight path data, and, when appropriate, the aircraft category to the processor  104 , via the communication bus  114 . The processor  104  in turn supplies appropriate display commands to the display device  112  so that the programmed flight plan, or at least portions thereof, and the current flight path may be displayed, either alone or in combination, on the display device  112 . The processor  104  also receives data from the navigation databases  106 , either directly or indirectly, and in turn supplies appropriate display commands to the display device so that at least a portion of the retrieved data are displayed on the display device  112  along with the flight plan and/or current flight path. In addition, the processor  104  receives data from the sensors  110 , including a GPS system, either directly or indirectly, and in turn supplies appropriate display commands to the display device so that at least a portion of the retrieved data including a zone of protection about an aircraft on the ground is displayed on display device  112 . It will additionally be appreciated that all or portions of the data mentioned herein may be entered manually by a user, such as the pilot  109 . 
     The display device  112  is used to display various images and data, in both a graphical and a textual format, and to supply visual feedback to the user  109  in response to the user input commands supplied by the user  109  to the user interface  102 . It will be appreciated that the display device  112  may be any one of numerous known displays suitable for rendering image and/or text data in a format viewable by the user  109 . Non-limiting examples of such displays include various cathode ray tube (CRT) displays, and various flat panel displays such as, various types of LCD (liquid crystal display) and TFT (thin film transistor) displays. The display may additionally be based on a panel mounted display, a HUD projection, or any known technology. In an exemplary embodiment, display device  112  includes a panel display. To provide a more complete description of the method that is implemented by the display system  100 , a general description of the display device  112  and its layout will now be provided. 
     Returning now to the description, as was previously noted the integrated flight display system of  FIG. 1  is shown as a preferred embodiment, since many aircraft of the business or airline categories have such integrated flight display system on board. It is possible, however to provide a simplified ground incursion avoidance system and display performing as a separate cockpit processor. Such a system is shown in  FIG. 2  and comprises a computer or processor  104  (similar components in  FIG. 2  are given the same numbers as their counterpart components of  FIG. 1 , although it is understood that the system of  FIG. 1  incorporates many more function than that of  FIG. 2 ). Processor  104  of  FIG. 2  may simply comprise a typical laptop computer that could be carried by a crewmember from aircraft to aircraft, or it could be a stand-alone computer on an aircraft with an integrated display system and dedicated to this one task or several other tasks. 
     Interfaced to the processor  104  is a GPS  120  or other device capable of relating the groundspeed, altitude, and position of the aircraft. This component is similar to the sensors  110  of  FIG. 1  and, as previously described, one of the sensors  110  of  FIG. 1  may well be a GPS receiver. Other inputs to the processor  104  of  FIG. 2  may include a source of airfield information  122  which may be obtained, for example, through a telecommunications link  124  to a ground station or satellite and surrounding aircraft information  126  which may also be obtained through the telecommunications link  124  to a ground station or satellite or through an ADS-B system. The display  112  of  FIG. 2  may be the processor&#39;s display itself (as in the case of a laptop computer) or a separate display in the event the processor  104  has no integral display. 
     With reference to  FIG. 3 , it seen that the display device  112  includes a display area  202  in which multiple graphical and textual images may be simultaneously displayed, preferably in different sections of the display area  202 . For example, general flight-related data  204 , a lateral situation display  206 , and a vertical situation display  208  may be displayed simultaneously, alone, or in various combinations, in various sections of the display area  202 . The general flight-related data  204  that is displayed may include various types of data related to the flight plan of the aircraft. Such data includes, but is not limited to, the flight identifier, route iteration number, a waypoint list and associated information, such as bearing and time to arrive, just to name a few. It will be appreciated that the general flight-related data  204  may additionally include various types of data associated with various types of flight hazards. Examples of these, and other types of data that may be displayed, are disclosed in U.S. Pat. No. 6,289,277, entitled “Interfaces for Planning Vehicle Routes,” which is assigned to the assignee of the present application, and the entirety of which is hereby incorporated by reference. 
     The lateral situation display  206  provides a two-dimensional lateral situation view of the aircraft along the current flight path, and the vertical situation display  208  provides either a two-dimensional profile vertical situation view or a perspective vertical situation view of the aircraft along the current flight path and/or ahead of the aircraft. While not depicted in  FIG. 2 , the lateral situation display  206  and the vertical situation display  208  may each selectively display various features including, for example, a top-view symbol and a side-view aircraft symbol, respectively, in addition to the displayed current flight plan, various navigation aids, and various map features below and/or ahead of the current flight path such as, for example, terrain, runways, and political boundaries. Additionally, the lateral situation display  206 , and in some instances the vertical situation display  208 , may each selectively display indicia representative of a zone of protection associated with the incursion avoidance system of the present invention. It will be appreciated that the lateral situation display  206  and the vertical situation display  208  preferably use the same scale so that the pilot can easily orient the present aircraft position to either section of the display area  202 . It will additionally be appreciated that the processor  104  may implement any one of numerous types of image rendering methods to process the data it receives from the navigation databases  106 , the navigation computer  108 , and or sensors  110  and render the views displayed therein. 
     It was noted above that the flight-related data  204 , the lateral situation display  206 , and the vertical situation display  208  may be displayed either alone or in various combinations. Hence, before proceeding further with the description, it should be appreciated that, for clarity and ease of explanation and depiction, in each of the figures referenced below only the lateral situation display  206  is shown being displayed in the display area  202  of the display device  112 . 
     Returning now to the description, as was previously noted, during ground maneuver the pilot  109  is responsible for keeping the aircraft safe from incursion with other surrounding aircraft and/or airfield structures (e.g. gate ramps, airport buildings, or the like). Thus, the processor  104  receives data, including data representative of aircraft ownship, surrounding aircraft, and/or airfield structures, determines a zone of protection associated with each, and supplies display commands that cause the lateral situation display  206 , in addition to or instead of one or more of the features mentioned above, to render a two-dimensional lateral situation view of a zone of protection, or envelope, associated with each of the aircraft ownship, surrounding aircraft, and/or airfield structures. The zone of protection may be color coded depending upon the level of excursion of the aircraft into another aircraft&#39;s zone of protection, or near an airfield structure. 
     Referring now to  FIG. 4 , the processor  104  is adapted to receive data representative of an aircraft during ground maneuvers and operable, in response thereto, to supply one or more image rendering display commands. The processor supplies display commands that cause the lateral situation display  206  to render a two-dimensional lateral situation view of a zone of protection associated with the aircraft. The lateral situation display  206  includes a top-view aircraft symbol  304  and an indicator of the zone of protection  312  associated with aircraft ownship. The lateral situation display  206  also preferably includes various map features including, but not limited to, a lateral two-dimensional view of airfield terrain  314  (e.g. runway, navigational aids, or the like) about which the aircraft  304  is maneuvering. It will be appreciated that for clarity only the terrain  314  map feature is shown in  FIG. 3 . 
     In displaying the lateral situation view  206  of the zone of protection  312 , the overall shape of the zone of protection  312  will elongate to provide early warning in a specific direction of aircraft ground travel and provide early warning of an impending incursion into another aircraft&#39;s zone of protection or an airfield structure. The shape of zone of protection  312  is determined by various factors, including but not limited to, the turn radius of the wings, nose and tail of the aircraft, the forward and backward groundspeed (e.g. pushback, taxi, of the like), the turn direction of the aircraft, and an early warning distance, noted as “x” in  FIG. 3 . The early warning distance “x” is a distance dependent upon the time and distance according to received aircraft data that would provide sufficient time and distance for the crew to react to an impending incursion. The zone of protection  312  will change as early warning distance “x” changes in response to received aircraft data. 
     Referring now to  FIGS. 5-7 , during a ground maneuver, the processor  104  supplies display commands that cause the lateral situation display  206  to render a two-dimensional lateral situation view of the zone of protection  312  associated with that specific aircraft. For purposes of explanation,  FIGS. 5-7  illustrate the associated zones of protection of two structures, and more specifically two aircraft traveling towards each other along a same directional path. In this particular embodiment, the lateral situation display  206  within each aircraft would include a top-view aircraft symbol  304 , indicating aircraft ownship, and the aircraft zone of protection  312  and a top-view approaching aircraft symbol  404 , indicating an approaching aircraft, and the aircraft zone of protection  412  associated with that aircraft. The lateral situation display  206  also preferably includes various map features including, but not limited to, a lateral two-dimensional view of airfield terrain  314 , including a runway  414 . The zone of protection  312  associated with aircraft ownship would change colors depending on immanency of an excursion into the other aircraft&#39;s zone of protection.  FIG. 5  illustrates separation of zones  312  and  412  and an intended colorization of the zones of protection  312  and  412  of green to indicate no threat is impending due to sufficient time and space for pilot correction.  FIG. 6  illustrates an intended amber colorization of zones of protection  312  and  412  to indicate an impending incursion between aircrafts indicated by symbols  304  and  404  unless corrective action is taken.  FIG. 7  illustrates an intended red colorization of zones of protection  312  and  412  to indicate immediate action is required to avert an incursion between aircraft indicated by symbols  304  and  404 . 
     In addition to causing the display device  112  to render an image of the zones of protection  312  or  412 , the processor  104  is also preferably configured to supply image rendering commands that cause the display device  112  to render advisory indicia. More specifically, the processor  104  is preferably coupled to receive position data representative of current aircraft position or aircraft track and is further operable, in response thereto, to supply one or more aircraft position or track rendering display commands. The display device  112  is further coupled to receive the rendering commands and is further operable, in response thereto, to simultaneously render and image of the aircraft position or aircraft track relative to the zones of protection  312  or  412 . Although the position and tracking data may be supplied from any one of numerous sources, in the depicted embodiments, the data is supplied from the sensors  110 , and more particularly the GPS. No matter the specific source of the data, an image rendering command will be supplied if these data indicate that the zone of protection  312  of aircraft  304  is within a predetermined distance of a zone of protection  412  of approaching aircraft  404  or tracking toward the boundary of the zone of protection  412 . The processor  104  supplies the image rendering command that causes the display device  112  to render the advisory indicia. It will be appreciated that this predetermined distance may vary. 
     The advisory indicia may additionally be rendered in response to various other parameters, not just distance. For example, the processor  104  may receive various other types of inertial data in addition to aircraft data during a ground maneuver, which are then processed to determine if aircraft  304  will reach or cross the boundary line of the zone of protection  412  in a predetermined amount of time. Data such as rate of speed, direction, and braking distance could be used to determine the amount of time for aircraft  304  to reach or cross the border of the zone of protection  412  from its current position. No matter the specific data used, if the processor  104  determines that the zone of protection  312  for aircraft  304  will reach the zone of protection  412  within the predetermined time period, the processor  104  supplies the image rendering commands that cause the display device  112  to render the advisory indicia. 
     It will be appreciated that the advisory indicia may be rendered according to any one of numerous paradigms. For example, as previously indicated the color in which the zone of protection  312  and/or boundary line of the zone of protection  312  are rendered could change, in whole or in part, from one color to another. In another example, the color in which zone of protection  412  or a boundary line of the zone of protection  412  are rendered could change, in whole or in part, from one color to another. As a specific example, the zone of protection  312  could be rendered in green if the aircraft  304  within the zone of protection  312  is not within the predetermined distance or predetermined time period for an incursion with the approaching aircraft  404  and its zone of protection  412 ; however, if the aircraft  304  within the zone of protection  312  moves within the predetermined distance or will reach or cross the zone of protection  412  in the predetermined time period, the zone of protection  312  is then rendered in amber. After the zones of protection  312  and  412  intersect, they would be rendered in red to indicate and imminent incursion. In an alternative exemplary embodiment, the advisory indicia is rendered as a separate symbol or set of symbols, such as text or other images. 
     It will additionally be appreciated that in still another alternative embodiment, which is shown in phantom in  FIG. 1 , the system  100  may be configured such that it additionally supplies visual and/or aural advisory indicia. For example, the system  100  could be configured to generate an aural warning when the aircraft  304  is within a predetermined distance of the zone of protection  412 . Alternatively, the system  100  could generate the aural warning  116  along with a visual indicator  118 , either on the display device  112  or a separate dedicated visual indicator. It will be appreciated that this aural warning could be implemented in anyone of numerous ways such as, for example, a buzzer, horn, alarm, or a voice indicator that states, for example, “Approaching aircraft—change path!” or “Threatened aircraft incursion—take corrective measures”. In the depicted embodiment, this aural indicator is generated by processor  104 ; however, it will be appreciated that it could additionally be generated by any one of numerous other external systems or devices. 
     Referring now to  FIG. 8 , during a ground maneuver an early warning zone of protection, envelope or bubble, may be displayed on lateral situation display  206  as indicated. In this particular embodiment, a zone of protection  512  of an aircraft  504  is indicated. The zone of protection  512  is drawn along the centerline  514  of the aircraft&#39;s steering angle, typically in the direction of movement of the aircraft as indicated by arrow  516 . Zone of protection  512  is indicated as comprised of three zonal areas  518 ,  520 , and  522  depending upon the proximity of the incursion to aircraft  504 . More specifically, zone of protection  518  provides an alert of incursion that will occur in excess of 10 seconds. It should be appreciated that zone of protection  518  may be colorized green to indicate no immediate threat of an incursion. Protective zone  520  provides an alert of an impending incursion in approximately 10 seconds. It should be appreciated that zone of protection  520  may be colorized amber to indicate the threat of an incursion. Corrective measures must be taken to eliminate this situation or an incursion will occur in approximately 10 seconds. Lastly, zone of protection  522  provides an alert of an impending incursion within 5 seconds. It should be appreciated that zone of protection  522  may be colorized red to indicate an immediate threat of an incursion. Corrective measures must be taken to eliminate this situation or an incursion will occur within 5 seconds. This zonal protective display provides a warning system to a flight crew in addition to that previously described and may additionally be used in conjunction with ground maneuvers about airfield structures, such as airport buildings, gate ramps, or the like. 
     During a ground holding pattern, aircraft must position themselves in alignment generally as illustrated in  FIGS. 9 and 10 . Display  112  would indicate in lateral situation display  206 , the terrain  614  of an airfield holding pad. More specifically, display  206  would indicate to a pilot of an aircraft, indicated in top-view by aircraft symbol  604 , a zone of protection  612  associated with the aircraft while in the holding pattern. In addition, display  206  would display information regarding any surrounding aircraft, or an aircraft approaching the holding pad, as indicated by top-view aircraft symbol  704 , and the zone of protection  712  associated with the approaching aircraft. The zones of protection  612  and  712  may be indicated by color, or the like as previously described to indicate no imminent incursion between the aircraft. As aircraft  704  nears aircraft  604  as illustrated in  FIG. 10 , zones of protection  612  and  712  may change to another color (e.g. amber) indicating an imminent incursion between the aircraft unless corrective measure is taken. It should be appreciated that the incursion avoidance system would include the capability of indicating zones of protection associated with any type of ground maneuver, including aircraft taxi to and from runways, and airport structures. 
       FIG. 11 . is a flow chart and schematic of an algorithm that may be used in practicing the instant invention. Preferably, the processor  104  implements software (or firmware) based algorithm or process  130  in accordance with the invention. The aircraft location, aircraft type, groundspeed, and future route  132  are continuously supplied to the process  130  during ground maneuvers. The future route may be provided by a navigation database  112  or may be entered manually by the aircraft crew. In addition, surrounding aircraft data  134  and airfield structure data  136  are continuously made available to the process  130  during ground maneuvers. The location and groundspeed of the aircraft may be provided by sensors  110  such as inertial sensors or by a GPS. The surrounding aircraft data  134  may be provided by an ADS-B system  138 . The airfield structure data  136  may be provided by terrain map overlays, or entered manually by the aircraft crew. In addition, an aircraft crew can provide an input  128  to the process  118  that indicates a parameter of interest. For example, “aircraft within 150 feet of zone of protection” or “airfield structure within 50 feet of zone of protection”. Alternatively, the threat thresholds may be preset. 
     The process  130  is performed by processor  104  that indicates the zone of protection of the aircraft in comparison with data from approaching aircraft or of known airfield structures. A comparison is made between the aircraft zones of protection and the corresponding alert threshold entered by the crew. If the severity of a data set exceeds its corresponding threshold  140  as preset, or entered by the crew, and alert is created for this data set. 
     When the alert is created the display  112  (in those systems where a ground incursion avoidance system display is used that is separate from the multifunction display of  FIG. 1 ) is activated. In this way, the display is not constantly active such that it may interfere with the concentration of the crew by displaying bright, colorful displays when the data to be displayed is not critical or the aircraft is en route. In the case of an integrated display system as set forth in  FIG. 1 , the display  112  switches from the currently operating mode, perhaps navigation or terrain display, to display the aircraft during ground maneuver and thus calling the crew&#39;s attention to the threat of an incursion  142  either continuously during the ground maneuver or only when it is within the preset parameters or parameters set by the crew. In either case the processor  104  may issue an alert in addition to activating the display, for example an audible alert may be issued by an annunciator (not shown) to alert the crew to evaluate the threat of incursion. 
     While preferred exemplary embodiments have been presented in the foregoing detailed description of preferred exemplary embodiments, it should be appreciated that a vast number of variations exist. It should also be appreciated that these preferred exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the ensuing detailed description will provide those skilled in the art with a convenient road map for implementing a preferred embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary preferred embodiment without departing from the spirit and scope of the invention as set forth in the appended claims.