Patent Publication Number: US-8977481-B1

Title: Unmanned aircraft navigation system

Description:
BACKGROUND INFORMATION 
     1. Field 
     The present disclosure relates generally to aircraft and, in particular, to displaying information used to control the movement of aircraft. Still more particularly, the present disclosure relates to a method and apparatus for displaying information for controlling the movement of unmanned aerial vehicles. 
     2. Background 
     Many aircraft have navigation displays for displaying information used to operate an aircraft. These navigation displays may display maps to an operator of the aircraft for use in operating the aircraft. These maps may include information, such as terrain, weather, airspace geometry, navigation aids, wind, routes, direction of travel, and other types of information. These types of displays are typically in the form of a map displayed in a top-down view. An icon representing the aircraft is typically displayed on a map in a location representing the current location of the aircraft. 
     Operators of an aircraft may also use other types of displays in a navigation system. For example, the operator may use a vertical situation profile display. This type of display may include information about terrain, attitude, and other information with respect to the aircraft. An icon representing the aircraft is displayed in a vertical position on the map indicating the altitude of the aircraft. Further, terrain ahead of the direction of travel of the aircraft also may be displayed on a vertical situation profile display. 
     Operators may also operate multiple aircraft using navigation displays. For example, the operator may be an air traffic control system operator managing multiple aircraft. In another instance, the operator may operate multiple unmanned aerial vehicles (UAVs). 
     When an operator manages multiple aircraft, such as unmanned aerial vehicles, displaying the route of the aircraft may not be as useful as desired in a top-down or vertical situation profile view. For example, unmanned aerial vehicles may have pre-planned routes. These pre-planned routes may be displayed on a top-down view of the unmanned aerial vehicles. The routes may overlap on this view of the unmanned aerial vehicles in some cases. 
     With this top-down view, an operator, however, may not know whether the overlap occurs at the same point in time. As a result, the display of routes for multiple unmanned aerial vehicles may not be as useful as desired for an operator of the unmanned aerial vehicles. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above as well as other possible issues. 
     SUMMARY 
     In one illustrative embodiment, a method for assisting in management of a number of unmanned aerial vehicles is present. Symbols used to display a number of pre-planned routes for the number of unmanned aerial vehicles are identified on a top-down view of the number of pre-planned routes. Flight information with respect to time for the number of unmanned aerial vehicles on a number of timelines is displayed using the symbols identified as being used to display the number of pre-planned routes for the number of unmanned aerial vehicles on the top-down view of the number of pre-planned routes. 
     In another illustrative embodiment, a method for displaying information for operating an aircraft is present. Symbols used to display a pre-planned route for the aircraft are identified on a top-down view of the pre-planned route. Flight information with respect to time for the aircraft is displayed on a timeline using the symbols identified as being used to display the pre-planned route for the aircraft on the top-down view. 
     In yet another illustrative embodiment, an apparatus comprises a display system and a navigation system. The navigation system is configured to identify symbols used to display a number of pre-planned routes for a number of unmanned aerial vehicles on a top-down view of the number of pre-planned routes. The navigation system is further configured to display flight information with respect to time for the number of unmanned aerial vehicles on a number of timelines using the symbols identified as being used to display the number of pre-planned routes for the number of unmanned aerial vehicles on the top-down view of the number of pre-planned routes. 
     The features and functions can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the illustrative embodiments are set forth in the appended claims. The illustrative embodiments, however, as well as a preferred mode of use, further objectives, and features thereof will best be understood by reference to the following detailed description of an illustrative embodiment of the present disclosure when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an illustration of an aircraft environment in accordance with an illustrative embodiment; 
         FIG. 2  is an illustration of a block diagram of an aircraft environment in accordance with an illustrative embodiment; 
         FIG. 3  is an illustration of a block diagram of a display for a display system in accordance with an illustrative embodiment; 
         FIG. 4  is an illustration of a display of a top-down view of a route of an aircraft in accordance with an illustrative embodiment; 
         FIG. 5  is an illustration of a display of a timeline of an aircraft in accordance with an illustrative embodiment; 
         FIG. 6  is an illustration of another display of a timeline of an aircraft in accordance with an illustrative embodiment; 
         FIG. 7  is an illustration of a display of a top-down view of routes of multiple aircraft in accordance with an illustrative embodiment; 
         FIG. 8  is an illustration of a display of a timeline of multiple aircraft in accordance with an illustrative embodiment; 
         FIG. 9  is an illustration of a flowchart of a process for displaying information for operating an aircraft in accordance with an illustrative embodiment; 
         FIG. 10  is an illustration of a flowchart of a process for assisting the management of a number of unmanned aerial vehicles in accordance with an illustrative embodiment; 
         FIG. 11  is an illustration of a flowchart of a process for indicating potential incursions in accordance with an illustrative embodiment; and 
         FIG. 12  is an illustration of a data processing system in accordance with an illustrative embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The illustrative embodiments recognize and take into account one or more different considerations. For example, the illustrative embodiments recognize and take into account that one manner in which information may be displayed to an operator is through the use of timelines. A timeline may be displayed in which events are shown with respect to spatial and temporal locations on a timeline. In other words, spatial information, such as altitudes, and temporal information, such as when events occur, are displayed on a timeline. 
     The illustrative embodiments recognize and take into account that although these timelines may provide information in a form that is more desirable for use in managing the operation of aircraft, such as unmanned aerial vehicles, these timelines may not be as easy to understand as desired. 
     The illustrative embodiments recognize and take into account that currently used timelines use symbols specifically generated to represent events or distances on the timeline. The illustrative embodiments recognize and take into account that the use of a timeline by itself may not provide as much information as desired for managing the operation of multiple unmanned aerial vehicles. As a result, an operator may use a top-down view with a timeline. 
     The illustrative embodiments recognize and take into account that the differences in the types of symbols may make using both a top-down view and a timeline more difficult than desired. An operator mentally correlates the symbols used in the top-down view with the symbols used on the timeline. This type of correlation takes time and concentration. The illustrative embodiments recognize and take into account that learning newer or different symbols from those typically used in a top-down view may require more time and effort than desired. Thus, the illustrative embodiments provide a method and apparatus for assisting in the management of a number of unmanned aerial vehicles. 
     With reference now to the figures and, in particular, with reference to  FIG. 1 , an illustration of an aircraft environment is depicted in accordance with an illustrative embodiment. In this illustrative example, aircraft environment  100  includes aircraft in the form of unmanned aerial vehicles  102 . As depicted, unmanned aerial vehicles  102  include unmanned aerial vehicle  104 , unmanned aerial vehicle  106 , and unmanned aerial vehicle  108 . 
     In these illustrative examples, unmanned aerial vehicles  102  are managed by an operator at ground station  110 . Unmanned aerial vehicles  102  may have pre-planned routes. For example, unmanned aerial vehicle  104  may fly on pre-planned route  112 , unmanned aerial vehicle  106  may fly on pre-planned route  114 , and unmanned aerial vehicle  108  may fly on pre-planned route  116 . 
     In managing unmanned aerial vehicles  102 , the operator may need to visualize these routes. For example, unmanned aerial vehicle  104  may fly closer than desired to unmanned aerial vehicle  108  while unmanned aerial vehicles  102  fly on the pre-planned routes. The operator may employ navigation system  118  to view flight information about the pre-planned routes for unmanned aerial vehicles  102 . 
     If the operator feels that unmanned aerial vehicle  104  may fly closer than desired to unmanned aerial vehicle  108 , the operator at ground station  110  may make adjustments to the pre-planned routes of either unmanned aerial vehicle  104  or unmanned aerial vehicle  108  when the operator is aware of such a situation. In the illustrative examples, an illustrative embodiment may be implemented at ground station  110  to assist the operator in managing operation of unmanned aerial vehicles  102 . 
     For example, in the illustrative embodiments, symbols used to display pre-planned routes for unmanned aerial vehicles  102  on a top-down view of the pre-planned routes are identified by navigation system  118 . Further, navigation system  118  displays flight information with respect to time for unmanned aerial vehicles  102  on timelines in a timeline view. The timeline view provides a different view of the flight information and may be used in conjunction with the top-down view to manage unmanned aerial vehicles  102 . 
     In the illustrative embodiments, the flight information is displayed on timelines in the timeline view using the symbols identified as being used to display the pre-planned routes for unmanned aerial vehicles  102  on the top-down view of the pre-planned routes. The use of the common symbols between the two views aids in linking information between the two views in the illustrative embodiments. 
     These timelines may be used to determine, for example, whether unmanned aerial vehicle  104  may fly too close to unmanned aerial vehicle  108  during flight along the pre-planned routes. In this manner, the operator at ground station  110  may be provided with greater situation awareness for managing unmanned aerial vehicles  102 . With the use of common symbols between the top-down view and the timeline view, the operator may more easily comprehend flight information displayed in the top-down view and the timeline view. 
     With reference now to  FIG. 2 , an illustration of a block diagram of an aircraft environment is depicted in accordance with an illustrative embodiment. In this illustrative example, aircraft environment  100  in  FIG. 1  is an example of one implementation for aircraft environment  200  shown in block form in this figure. 
     Aircraft environment  200  includes number of aircraft  202 . As used herein, a “number of”, when used with reference to items, means one or more items. For example, number of aircraft  202  is one or more aircraft. In this illustrative example, number of aircraft  202  takes the form of number of unmanned aerial vehicles  204 . 
     Operator  206  at location  208  manages the operation of number of unmanned aerial vehicles  204  from location  208 . Location  208  may be, for example, without limitation, a ground location, an aircraft, a ship, or some other suitable location. 
     As depicted, operator  206  manages the operation of number of aircraft  202  using aircraft control system  209 . Aircraft control system  209  includes controller  210  and navigation system  212 . 
     As depicted, controller  210  is configured to control the operation of number of unmanned aerial vehicles  204 . Operator  206  obtains information to manage number of unmanned aerial vehicles  204  through navigation system  212 . 
     In these illustrative examples, controller  210  and navigation system  212  in aircraft control system  209  may be implemented in computer system  214 . Computer system  214  may be a number of computers. When more than one computer is present, those computers may be in communication with each other through a communications medium, such as a network. 
     Controller  210  and navigation system  212  may be implemented in software, hardware, or a combination of the two. When software is used, the operations performed by the components may be implemented in the program code configured to be run on a processor unit. When hardware is employed, the hardware may include circuits that operate to perform the operations in the components. 
     In the illustrative examples, the hardware may take the form of a circuit system, an integrated circuit, an application specific integrated circuit (ASIC), a programmable logic device, or some other suitable type of hardware configured to perform a number of operations. With a programmable logic device, the device is configured to perform the number of operations. The device may be reconfigured at a later time or permanently configured to perform the number of operations. Examples of programmable logic devices include, for example, a programmable logic array, a programmable array logic, a field programmable logic array, a field programmable gate array, and other suitable hardware devices. Additionally, the processes may be implemented in organic components integrated with inorganic components and/or comprised entirely of organic components excluding a human being. For example, the processes may be implemented as circuits in organic semiconductors. 
     In this illustrative example, operator  206  may interact with controller  210  and navigation system  212  through user interface  216 . User interface  216  is hardware and may also include software. User interface  216  includes display system  218  and user input system  220  in this depicted example. Display system  218  is one or more display devices. These display devices may include, for example, without limitation, at least one of a liquid crystal display, a plasma display, and other suitable types of displays. User input system  220  is one or more user input devices. These user input devices may be, for example, without limitation, at least one of a touch screen, a physical button, a keyboard, a mouse, and other suitable types of input devices. 
     As used herein, the phrase “at least one of”, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of each item in the list may be needed. For example, “at least one of item A, item B, and item C” may include, without limitation, item A or item A and item B. This example also may include item A, item B, and item C, or item B and item C. In other examples, “at least one of” may be, for example, without limitation, two of item A, one of item B, and 10 of item C; four of item B and seven of item C; and other suitable combinations. 
     As depicted, navigation system  212  may provide flight information  222  for number of unmanned aerial vehicles  204  to operator  206 . This flight information may be displayed in display  224  in display system  218 . Flight information  222  is configured to be displayed in display  224  in a manner that provides operator  206  with a desired level of situation awareness with respect to the movement of number of unmanned aerial vehicles  204 . In these illustrative examples, flight information  222  may be routing information or other information for number of unmanned aerial vehicles  204 . 
     In these illustrative examples, display  224  is generated by navigation system  212 . In generating display  224 , navigation system  212  may use navigation database  226  and number of flight plans  228  for number of unmanned aerial vehicles  204 . Number of flight plans  228  may include number of pre-planned routes  230  for number of unmanned aerial vehicles  204 . 
     In this illustrative example, flight information  222  in display  224  may include at least one of top-down view  232  and timeline view  234 . In this illustrative example, top-down view  232  and timeline view  234  include flight information  222 . In particular, top-down view  232  provides a spatial view of flight information  222 . Timeline view  234  provides a temporal view of flight information  222 . Flight information  222  is based on number of pre-planned routes  230  for number of unmanned aerial vehicles  204  in number of flight plans  228 . In these illustrative examples, top-down view  232  and timeline view  234  may display some of the same flight information in flight information  222  and also may display different portions of flight information  222  from each other. In other words, timeline view  234  may display some information not shown in top-down view  232  in these illustrative examples. 
     Top-down view  232  and timeline view  234  are linked to each other. Linking displaying of flight information  222  with respect to time for number of unmanned aerial vehicles  204  in timeline view  234  with displaying top-down view  232  occurs such that changes in number of pre-planned routes  230  displayed in top-down view  232  are reflected in timeline view  234 . For example, operator  206  may change number of pre-planned routes  230 . Additionally, the progress of number of unmanned aerial vehicles  204  along number of pre-planned routes  230  in top-down view  232  also may be reflected in timeline view  234 . 
     Further, the linking of top-down view  232  and timeline view  234  also occurs in a manner that allows operator  206  to transition between the two views with a desired level of speed and concentration. In these illustrative examples, symbols may be used to link these two views to each other. For example, symbols in top-down view  232  are also used in timeline view  234 . In particular, symbols used with respect to displaying flight information  222  for number of pre-planned routes  230  in top-down view  232  are reused in displaying flight information  222  for number of pre-planned routes  230  in timeline view  234 . 
     With timeline view  234 , operator  206  may be able to determine whether an incursion may occur between unmanned aerial vehicles in number of unmanned aerial vehicles  204  as they fly along number of pre-planned routes  230 . In these illustrative examples, an incursion may occur when two or more unmanned aerial vehicles fly too closely to each other. If operator  206  identifies an incursion on timeline view  234 , operator  206  may make adjustments to number of pre-planned routes  230  for number of unmanned aerial vehicles  204 . The incursion on timeline view  234  is a potential incursion if the unmanned aerial vehicles will likely fly closer to each other than desired if the unmanned aerial vehicles continue to operate without changes to number of pre-planned routes  230 . 
     Through the use of the same symbols in both top-down view  232  and timeline view  234 , less time, concentration, and experience may be needed to use flight information  222  in timeline view  234  by operator  206  as compared to other timelines. As a result, operator  206  may be able to more efficiently manage number of unmanned aerial vehicles  204 . For example, with navigation system  212  and the use of timeline view  234  in which symbols used are common to both top-down view  232  and timeline view  234 , operator  206  also may be able to manage greater numbers of unmanned aerial vehicles. For example, the management may be separation management of greater numbers of unmanned aerial vehicles. 
     Turning now to  FIG. 3 , an illustration of a block diagram of a display for a display system is depicted in accordance with an illustrative embodiment. As depicted, one configuration for display  224  is shown in this figure. 
     As depicted, display  224  includes top-down view  232  and timeline view  234 . In top-down view  232 , number of pre-planned routes  230  is displayed using symbols  300 . Symbols  300  may be used to depict various forms of flight information  222  in  FIG. 2 . In these illustrative examples, symbols  300  take the form of map symbols  302 . For example, map symbols  302  may represent information, such as, for example, without limitation, airports, navigation aids, airways, airspace boundaries, jet routes, altitude restrictions, waypoints, airspace information, and other suitable information. 
     In these illustrative examples, number of graphical indicators  304  is used to represent number of unmanned aerial vehicles  204  in  FIG. 2 . Number of graphical indicators  304  may be displayed in association with number of pre-planned routes  230  in a location that indicates the progress of number of unmanned aerial vehicles  204  along number of pre-planned routes  230  in top-down view  232 . 
     Timeline view  234  includes number of timelines  306 . In these illustrative examples, each timeline in number of timelines  306  is associated with an unmanned aerial vehicle in number of unmanned aerial vehicles  204 . Number of timelines  306  displays flight information  222  with respect to time for number of unmanned aerial vehicles  204 . In this illustrative example, number of timelines  306  is displayed in timeline view  234  using symbols  308 . Symbols  308  used in number of timelines  306  are based on symbols  300  used in top-down view  232 . 
     In these illustrative examples, symbols  308  include map symbols  310 . Map symbols  310  may be some or all of map symbols  302  from symbols  300 . In this manner, top-down view  232  is linked to timeline view  234  through the use of common symbols. This linking using common symbols between the views may aid an operator in more quickly understanding flight information  222  for number of unmanned aerial vehicles  204  as presented in top-down view  232  and timeline view  234 . 
     In addition, timeline view  234  may also display number of events  312 . Number of events  312  may not be displayed in top-down view  232 . Number of events  312  may be displayed using event symbols  314  in symbols  308 . As a result, symbols  308  also may include other symbols not used in symbols  300 . 
     In these illustrative examples, number of events  312  may be identified from at least one of number of flight plans  228  in  FIG. 2 , an air traffic controller, and other suitable sources. Number of events  312  may be displayed on one or more of number of timelines  306 . Additional symbols may be present for number of events  312 . For example, without limitation, number of events  312  may be selected from at least one of hold, climb, take pictures, drop payload, drop flaps, raise flaps, lower landing gear, and other suitable types of events. A symbol may be selected for each of these types of events. 
     Additionally, number of timelines  306  also may be displayed in a manner to indicate relative positions  316  of number of unmanned aerial vehicles  204  along number of pre-planned routes  230 . Relative positions  316  may be, for example, positions of one unmanned aerial vehicle at different points in time. In another illustrative example, relative positions  316  may be positions between different unmanned aerial vehicles. 
     For example, vertical distance  318  may be indicated on number of timelines  306 . Vertical distance  318  for number of unmanned aerial vehicles  204  may be identified using number of timelines  306 . Vertical distance  318  is a relative distance for number of unmanned aerial vehicles  204 . Vertical distance  318  may be identified as relative changes occur in position for a single unmanned aerial vehicle in number of unmanned aerial vehicles  204 . In other illustrative examples, vertical distance  318  may be identified as relative changes occur in position between multiple unmanned aerial vehicles in number of unmanned aerial vehicles  204 . 
     Linking displaying of flight information  222  with respect to time for number of unmanned aerial vehicles  204  on number of timelines  306  in timeline view  234  with displaying top-down view  232  may also occur such that changes in number of pre-planned routes  230  displayed on top-down view  232  are reflected in number of timelines  306 . For example, operator  206  in  FIG. 2  may change number of pre-planned routes  230 . Additionally, the progress of number of unmanned aerial vehicles  204  along number of pre-planned routes  230  in top-down view  232  also may be reflected in number of timelines  306  in timeline view  234 . 
     For example, number of graphical indicators  320  may be displayed on number of timelines  306 . Number of graphical indicators  320  represents number of unmanned aerial vehicles  204  in these illustrative examples. Number of graphical indicators  320  may be displayed in locations on number of timelines  306  to indicate progress of number of unmanned aerial vehicles  204 . 
     The illustration of aircraft environment  200  in  FIG. 2  and the components in aircraft environment  200  in  FIG. 2  and  FIG. 3  are not meant to imply physical or architectural limitations to the manner in which different illustrative embodiments may be implemented. Other components in addition to or in place of the ones illustrated may be used. Some components may be unnecessary. Also, the blocks are presented to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and divided into different blocks when implemented in an illustrative embodiment. 
     For example, the illustrative embodiments may be applied to other types of aircraft other than unmanned aerial vehicles. For example, aircraft control system  209  may be located in an aircraft, and operator  206  may be a pilot in the aircraft that manages the operation of the aircraft using top-down view  232  and timeline view  234 . In still other illustrative examples, operator  206  may be an air traffic controller and may manage the flight of multiple aircraft. The air traffic controller may send instructions to the pilot of the aircraft based on flight information  222  using top-down view  232  and timeline view  234 . 
     Turning now to  FIG. 4 , an illustration of a display of a top-down view of a route of an aircraft is depicted in accordance with an illustrative embodiment. In this illustrative example, display  400  is an example of one implementation for display  224  in  FIG. 2 . Top-down view  402  in display  400  is an example of one implementation for top-down view  232  in display  224  in  FIG. 2 . 
     As depicted, top-down view  402  in display  400  includes map  403 . Route  404  is displayed on map  403 . Route  404  is a pre-planned route in this illustrative example. As depicted, route  404  is displayed on map  403  using symbols  406 . 
     In these illustrative examples, route  404  may be a flight path for an unmanned aerial vehicle traveling in the direction of arrow  408 . As the aircraft continues to travel along route  404 , the direction of travel may change. For example, the unmanned aerial vehicle may travel along route  404  in the direction of arrow  410  after climbing to a different altitude. 
     In these illustrative examples, symbols  406  include map symbols  412 . Map symbols  412  may provide information about particular points along route  404 . For example, without limitation, map symbols  412  may include a distance between two waypoints, a waypoint, a navigation aid, a flight trajectory, a geographic location, an airport, an intersection point with a route for another aircraft, an altitude, a total distance from a start point, or some other suitable map symbol. 
     In these illustrative examples, map symbols  412  include map symbol  414 , map symbol  416 , map symbol  418 , and map symbol  420 . Map symbol  414  may be a geographic indicator for an airport in these illustrative examples. Map symbol  416  is a navigation aid in close proximity to the airport in this illustrative example. Map symbol  418  and map symbol  420  may be symbols for other geographic indicators along the flight path for an aircraft traveling along route  404 . Of course, other map symbols may be shown in display  400  other than map symbols  414 ,  416 ,  418 , and  420 . For example, a map symbol indicating a vector path, a magnetic heading, or a distance traveled along a particular route may be depicted. 
     Turning now to  FIG. 5 , an illustration of a display of a timeline of an aircraft is depicted in accordance with an illustrative embodiment. In this illustrative example, display  500  is an example of one implementation for display  224  in  FIG. 2 . More specifically, timeline view  502  is an example of one implementation for timeline view  234  in display  224  in  FIG. 2 . 
     Timeline view  502  in display  500  depicts the flight of an aircraft along a route over different points in time. Particularly, timeline view  502  provides a timeline representation of route  404  from top-down view  402  in  FIG. 4 . Timeline view  502  depicts timeline  504  for an aircraft traveling along route  404  in  FIG. 4 . 
     In these illustrative examples, timeline view  502  includes symbols  506  along timeline  504 . Symbols  506  are comprised of map symbols  508  and event symbols  510 . As depicted, map symbols  508  correspond to map symbols  412  in  FIG. 4 . 
     Further, map symbols  508  depicted in timeline view  502  include map symbol  514 , map symbol  516 , map symbol  518 , and map symbol  520 . Map symbols  514 ,  516 ,  518 , and  520  correspond to map symbols  414 ,  416 ,  418 , and  420  in  FIG. 4 , respectively. Map symbols in map symbols  508  are placed on timeline  504 . As the aircraft travels further along timeline  504 , the relative position of map symbols  508  may change. 
     Additionally, events are depicted on timeline  504  using event symbols  510 . Event symbols  510  provide operators of aircraft additional information about and instructions for flight. For example, an event symbol in event symbols  510  may represent an event, such as climb, descend, hold, or some other type of event. 
     Lines  550 ,  552 ,  554 ,  556 , and  558  represent relative time between symbols  506  on timeline  504 . The lengths of these lines provide relative times for travel from one location to another location as represented in map symbols  508 , the time between events as indicated by event symbols  510 , or a combination of the two. 
     In these illustrative examples, line  550  represents the time of travel between map symbol  514  and map symbol  516 . Line  552  is dotted line  553 , which represents the time of travel during the climb and hold maneuver at event symbol  526 . Line  554  represents the relative time from the completion of the hold and climb event at event symbol  526  to map symbol  518 . Line  556  represents the relative time between map symbol  518  and map symbol  520 . Line  558  represents the time of travel between map symbol  520  and another map symbol in map symbols  508  (not shown). 
     As the operator of an aircraft traveling along timeline  504  changes one or more flight parameters, the distance between map symbols may increase or decrease, depending on the change in flight parameters. For example, if an operator increases the speed of the aircraft during the time of travel between map symbol  518  and map symbol  520 , the relative time between these two points will decrease. As a result, the length of line  556  on timeline  504  will be shorter. 
     In this illustrative example, the flight begins at map symbol  514  and proceeds toward a navigation aid at map symbol  516 . A hold and climb occurs at the navigation aid as indicated by event symbol  526 . Dotted line  553  represents the time along timeline  504  that the aircraft performs the hold and climb maneuver. After the hold and climb is finished, the aircraft progresses along the current flight path to map symbol  518 . 
     At map symbol  518 , the aircraft then climbs as indicated by event symbol  530 . At event symbol  530 , the aircraft begins the climb at the time the aircraft reaches event symbol  530  without the need to hold. This climb is an en-route climb without a hold along line  556 . The climb is completed along line  556 . 
     In these illustrative examples, the progress of an unmanned aerial vehicle along timeline  504  may be identified using graphical indicator  524 . Graphical indicator  524  takes the form of an icon that represents the unmanned aerial vehicle in this example. As time passes, graphical indicator  524  is moved along timeline  504  to indicate the progress of the unmanned aerial vehicle. In this illustrative example, graphical indicator  524  along timeline  504  corresponds to the aircraft flying in a location between map symbol  516  and map symbol  518 . 
     In other illustrative examples of timeline  504 , graphical indicator  524  may have a fixed position in display  500 . In this example, graphical indicator  524  represents the position of the unmanned aerial vehicle at the current time. As time progresses, timeline  504  will shift relative to graphical indicator  524 . For example, as an unmanned aerial vehicle flies along timeline  504  toward map symbol  520 , the display of map symbol  520  in display  500  will move closer to graphical indicator  524 . Once the unmanned aerial vehicle passes map symbol  520 , map symbol  520  may no longer be displayed in timeline  504  in display  500 . 
     In still other illustrative examples, map symbol  520  passed by the aircraft may be displayed before graphical indicator  524  in timeline  504 . Map symbol  520  may be displayed for a period of time after the aircraft has passed map symbol  520 . In this particular example, map symbol  520  may be grayed-out to symbolize a location that has been passed by the aircraft. 
     In this illustrative example, event symbol  526  is a symbol for a climb and hold event. When graphical indicator  524  moves along timeline  504  and reaches event symbol  526 , the aircraft maintains a hold pattern while climbing. Dotted line  553  indicates the time used to complete the climb and hold event. When the climb and hold event is completed, line  554  symbolizes the flight of the aircraft as it travels further along route  404 . In other words, during the time represented by dotted line  553 , the aircraft is not traveling horizontally along route  404 . 
     In these illustrative examples, event symbol  530  is a symbol for a climb event. Thus, when graphical indicator  524  reaches event symbol  530  along timeline  504 , the aircraft will begin a climb to about 7,000 feet. In this example, event symbol  530  is aligned with map symbol  520 . As a result, the aircraft begins to climb when the aircraft reaches map symbol  520 , because the aircraft also reaches event symbol  530 . 
     The illustration of map symbols  508  and event symbols  510  in timeline view  502  occur in substantially real time. As the aircraft travels along route  404 , symbols  506  in timeline  504  change to depict the types of symbols related to a particular period of time. That period of time may be a pre-set period of time or changed by user input. For example, timeline view  502  may display timeline  504  for the entire duration of the flight of the aircraft along timeline  504 . In another illustrative example, timeline view  502  may only display timeline  504  for about 10 minutes of flight. 
     Turning now to  FIG. 6 , an illustration of another display of a timeline of an aircraft is depicted in accordance with an illustrative embodiment. In this illustrative example, timeline view  602  in display  600  may be another implementation for timeline view  234  in display  224  in  FIG. 2 . In this illustrative example, timeline  604  is depicted in timeline view  602 . In this illustrative example, timeline  604  uses the same symbols as timeline  504  in  FIG. 5 . Timeline  604  is depicted such that the relative vertical distance is shown for the unmanned aerial vehicle at different points in time. 
     For example, lines  550 ,  552 ,  554 ,  556 , and  558  along timeline  604  are graphically depicted such that the operator may see an additional view of the proposed climb at event symbol  526 . In this illustrative example, more information about relative distances is provided to the viewer of timeline  604 . For example, dotted line  553  is drawn at an angle relative to line  550  and line  554  to represent the relative vertical distance of the hold and climb indicated by event symbol  526 . This relative vertical distance is between line  550  and line  552 . The aircraft is at a higher altitude at line  554  than at line  550  in this particular example. 
     Similarly, the relative vertical distance traveled along line  556  with the climb indicated by event symbol  530  is also graphically depicted in this illustrative example. The solid line used for line  556  indicates that the aircraft is completing an en-route climb instead of a hold and climb maneuver. The relative vertical distance of travel may be depicted in a display for one aircraft or multiple aircraft in these illustrative examples. 
     Turning now to  FIG. 7 , an illustration of a display of a top-down view of routes of multiple aircraft is depicted in accordance with an illustrative embodiment. In this illustrative example, display  700  with top-down view  702  is an example of an implementation for display  224  with top-down view  232  in  FIG. 2 . 
     As depicted, top-down view  702  may be map  703 . Map  703  shows route  704 , route  706 , and route  708 . In these illustrative examples, each route is a pre-planned route and represents a different unmanned aerial vehicle. As can be seen, these routes may intersect in these illustrative examples. The intersection of routes may occur at the same time or different times. Of course, top-down view  702  may be used to manage pre-planned routes for other types of aircraft other than unmanned aerial vehicles. Further, top-down view  702  may depict additional numbers of routes other than route  704 , route  706 , and route  708 . 
     In this illustrative example, route  704  includes map symbols  710 , route  706  includes map symbols  712 , and route  708  includes map symbols  714 . As depicted, map symbols  710  for route  704  include map symbol  720 , map symbol  722 , map symbol  724 , and map symbol  728 . Map symbols  712  for route  706  include map symbol  730 , map symbol  724 , map symbol  734 , and map symbol  736 . Map symbols  714  for route  708  include map symbol  738 , map symbol  740 , map symbol  734 , and map symbol  728 . 
     In these illustrative examples, route  704  may cross route  706  at a location indicated by map symbol  724 . Further, route  706  may cross route  708  at another location indicated by map symbol  734 . With the use of only top-down view  702 , an operator may not know at what point in time these crossing of routes may occur. As a result, one route may cross another route at substantially the same time and risk an incursion. 
     Turning now to  FIG. 8 , an illustration of a display of a timeline of multiple aircraft is depicted in accordance with an illustrative embodiment. In this illustrative example, display  800  includes timeline view  802 . More specifically, display  800  with timeline view  802  is an example of one implementation of display  224  with timeline view  234  in  FIG. 2 . 
     In these illustrative examples, timeline view  802  includes symbols  806  along timeline  804 , symbols  808  along timeline  810 , and symbols  812  along timeline  814 . Symbols  806 , symbols  808 , and symbols  812  are comprised of map symbols  816  and event symbols  818 . As depicted, map symbols  816  correspond to map symbols  710 , map symbols  712 , and map symbols  714  in  FIG. 7 . Particularly, map symbols  720 ,  722 ,  724 , and  728  along route  704  correspond to map symbols  820 ,  822 ,  824 , and  828  on timeline  804 ; map symbols  730 ,  724 ,  734 , and  736  along route  706  correspond to map symbols  830 ,  824 ,  834 , and  836  on timeline  810 ; and map symbols  738 ,  740 ,  734 , and  728  along route  708  correspond to map symbols  838 ,  840 ,  834 , and  828  on timeline  814 , respectively. 
     Event symbols  818  include event symbol  844 . As depicted, when an aircraft flying along a route in timeline  804  reaches event symbol  844 , the aircraft will climb about 7,000 feet. Graphical indicators  848  are used to indicate the progress of unmanned aerial vehicles along timelines  804 ,  810 , and  814 . For example, graphical indicator  850  is displayed on timeline  804 . Graphical indicator  852  is displayed on timeline  810 , and graphical indicator  854  is displayed on timeline  814 . Alternatively, a line may be used to indicate progress along timelines  804 ,  810 , and  814 . 
     Additionally, timeline view  802  shows incursion indicator  856 , incursion indicator  858 , and incursion indicator  860  in display  800 . An incursion is indicated when two unmanned aerial vehicles traveling along different timelines reach a location at substantially the same time. An incursion indicator is a graphical indicator indicating that two or more unmanned aerial vehicles may fly closer than desired to each other at a particular point in time. In these illustrative examples, incursion indicator  856  is shown when the trajectory of an aircraft traveling along timeline  804  and another aircraft traveling along timeline  810  result in these aircraft reaching the same location at substantially the same time. 
     In these illustrative examples, the position of graphical indicator  850  on timeline  804 , graphical indicator  852  on timeline  810 , and graphical indicator  854  on timeline  814  indicate how much time is left before an incursion may occur. 
     To prevent an incursion from occurring at incursion indicator  856 , an operator managing the unmanned aerial vehicles may change one or more of the routes along which the unmanned aerial vehicles travel. The route may be changed such that one or more of the unmanned aerial vehicles changes speed, direction, altitude, or some combination thereof. If the changes are sufficient to avoid the upcoming incursion, the timeline display for one or both of the operators of unmanned aerial vehicles traveling along these timelines may update automatically. In this illustrative example, the unmanned aerial vehicle traveling along timeline  810  may slow down or speed up to avoid the incursion. 
     In these illustrative examples, incursion indicator  856 , incursion indicator  858 , and incursion indicator  860  are depicted having different levels of risk of the incursion. For example, the likelihood of an incursion at incursion indicator  856  of timeline  804  and timeline  810  indicates a higher risk than incursion indicator  858  of timeline  810  and timeline  814 , because incursion indicator  856  is earlier in time than incursion indicator  858 . In other illustrative examples, incursion indicator  856  may indicate a lower risk than incursion indicator  858  even though incursion indicator  856  may be earlier in time. For example, the level of separation may be less for the incursion indicated by incursion indicator  858  than for incursion indicator  856 . 
     The levels of risk of incursion in these illustrative examples may be depicted using color, shading, line style, or other suitable types of graphical indicators. In one illustrative example, incursion indicator  856  may be red, while incursion indicator  858  may be yellow. In this example, red may indicate a higher level of risk than yellow. 
     The operator may change flight parameters to avoid or reduce the level of risk of incursion. For example, the operator may change at least one of air speed, altitude, bearing, and other flight parameters. As an operator of an unmanned aerial vehicle makes adjustments to flight parameters to avoid a potential incursion at incursion indicator  856 , incursion indicator  856  may change color to represent a change in the risk of the incursion. The change of flight parameters may also affect the potential for incursion at incursion indicator  858 . In other words, one or more of incursion indicator  856 , incursion indicator  858 , and incursion indicator  860  may change color in response to the same change in flight parameters. 
     In other illustrative examples, timeline view  802  in display  800  may update the display of symbols on timelines  804 ,  810 , and  814  in response to changes in other conditions other than changes to the operation of the unmanned aerial vehicles. For example, without limitation, timeline view  802  may change based on weather conditions, wind, projected fuel burn, heading, altitude, terrain, fly-zone restrictions, or other suitable changes in the flight of aircraft in display  800 . For example, the changes may change the time at which different map symbols, event symbols, or some combination thereof is reached. In other words, the distance between map symbols, event symbols, or some combination thereof may change to reflect changes in time as to when locations are reached and when events occurs. 
     The illustration of the displays with top-down views and timeline views in  FIGS. 4-8  are only provided as illustrative examples of implementations for the displays and views. These depicted views are not meant to limit the manner in which the views may be displayed in other illustrative embodiments. For example, in some illustrative embodiments, a single graphical indicator may be used to indicate the progress of unmanned aerial vehicles along timelines. In another illustrative example, timelines may be arranged vertically rather than horizontally. 
     In yet other illustrative examples, no graphical indicators may be used behind the present position of the aircraft. Rather, progress in a display is shown by the view of the remaining route depicted on the display. In other words, an operator may only see what is ahead of the aircraft along the timeline. 
     In another illustrative example, incursion indicators may be located along lines on the timeline and not on symbols on the timeline. Incursion indicators may indicate a time not represented by a map symbol on the timeline where aircraft may be separated by a distance that is less than desired. 
     Further, the different illustrative embodiments in  FIGS. 4-8  may be used together to provide the operator of an aircraft in a display valuable information about the flight of the aircraft. For example, the timeline views in  FIG. 5  and  FIG. 6  may be used with the top-down view in  FIG. 4 , while the top-down view in  FIG. 7  and the timeline view in  FIG. 8  may be used together. 
     Turning now to  FIG. 9 , an illustration of a flowchart of a process for displaying information for operating an aircraft is depicted in accordance with an illustrative embodiment. The process illustrated in  FIG. 9  may be implemented in navigation system  212  in  FIG. 2 . 
     The process begins by identifying symbols used to display a pre-planned route for an aircraft on a top-down view of the pre-planned route (operation  900 ). The process then displays flight information with respect to time for the aircraft on a timeline using the symbols identified as being used to display the pre-planned route on the top-down view (operation  902 ), with the process terminating thereafter. 
     With reference now to  FIG. 10 , an illustration of a flowchart of a process for assisting the management of a number of unmanned aerial vehicles is depicted in accordance with an illustrative embodiment. The process illustrated in  FIG. 10  may be implemented in navigation system  212  in  FIG. 2 . 
     The process begins by identifying a number of pre-planned routes for a number of unmanned aerial vehicles (operation  1000 ). The process then identifies a current position of the number of unmanned aerial vehicles (operation  1002 ). The process then identifies a map for the number of unmanned aerial vehicles based on the current position of the number of unmanned aerial vehicles (operation  1004 ). 
     The process then places the number of pre-planned routes on the map with a number of graphical indicators that indicate the current position for the number of unmanned aerial vehicles on the number of pre-planned routes to form a top-down view (operation  1006 ). The process then displays the top-down view on a display system (operation  1008 ). 
     The process identifies a set of map symbols based on map symbols used in the top-down view (operation  1010 ). The process identifies a number of events for the number of pre-planned routes (operation  1012 ). The process then identifies a number of event symbols for the number of events (operation  1014 ). These events may be identified from a number of flight plans for the number of unmanned aerial vehicles. The number of event symbols is added to a set of symbols (operation  1016 ). In operation  1016 , the set of symbols includes both map symbols and event symbols. 
     The process then generates a number of timelines using the set of symbols (operation  1018 ). A number of graphical indicators are placed on the number of timelines in which the number of graphical indicators indicates the progress of the number of unmanned aerial vehicles on the number of timelines. For example, the number of graphical indicators may include a graphical indicator on each timeline that is aligned with the other graphical indicators on the other timelines. In another example, a single graphical indicator may extend through all of the timelines. The process then displays a timeline view with the number of timelines (operation  1020 ), with the process returning to operation  1000 . When returning to operation  1000 , changes to the number of pre-planned routes, if any, may be identified. 
     With reference to  FIG. 11 , an illustration of a flowchart of a process for indicating potential incursions is depicted in accordance with an illustrative embodiment. The process illustrated in  FIG. 11  may be implemented in navigation system  212  in  FIG. 2 . 
     The process begins by identifying timelines displayed in the timeline view (operation  1100 ). The timelines are timelines managed by an operator in these illustrative examples. For example, the timelines may be for unmanned aerial vehicles managed by a pilot. In another example, the timelines may be for aircraft managed by an air traffic controller. 
     The process identifies times along the timeline where two or more aircraft may be separated by a distance that is less than desired (operation  1102 ). The process then identifies a level of risk for each potential incursion (operation  1104 ). An incursion indicator is identified for each potential incursion based on the level of risk for the potential incursion (operation  1106 ). 
     The process displays an incursion indicator on the timelines displayed in the timeline view for aircraft that have a potential incursion (operation  1108 ), with the process then returning to operation  1102 . The aircraft with potential incursions may change as flight parameters for operating the aircraft change. These changes may be made by the operator of the aircraft to reduce the level of risk of incursion or remove the potential incursion. With these changes, the display of incursion indicators displayed on the timelines change. 
     Turning now to  FIG. 12 , an illustration of a data processing system is depicted in accordance with an illustrative embodiment. Data processing system  1200  may be used to implement computer system  214  in  FIG. 2 . In this illustrative example, data processing system  1200  includes communications framework  1202 , which provides communications between processor unit  1204 , memory  1206 , persistent storage  1208 , communications unit  1210 , input/output (I/O) unit  1212 , and display  1214 . In this example, communications framework  1202  may take the form of a bus system. 
     Processor unit  1204  serves to execute instructions for software that may be loaded into memory  1206 . Processor unit  1204  may be a number of processors, a multi-processor core, or some other type of processor, depending on the particular implementation. 
     Memory  1206  and persistent storage  1208  are examples of storage devices  1216 . A storage device is any piece of hardware that is capable of storing information, such as, for example, without limitation, data, program code in functional form, and/or other suitable information either on a temporary basis and/or a permanent basis. Storage devices  1216  may also be referred to as computer readable storage devices in these illustrative examples. Memory  1206 , in these examples, may be, for example, a random access memory or any other suitable volatile or non-volatile storage device. Persistent storage  1208  may take various forms, depending on the particular implementation. 
     For example, persistent storage  1208  may contain one or more components or devices. For example, persistent storage  1208  may be a hard drive, a flash memory, a rewritable optical disk, a rewritable magnetic tape, or some combination of the above. The media used by persistent storage  1208  also may be removable. For example, a removable hard drive may be used for persistent storage  1208 . 
     Communications unit  1210 , in these illustrative examples, provides for communications with other data processing systems or devices. In these illustrative examples, communications unit  1210  is a network interface card. 
     Input/output unit  1212  allows for input and output of data with other devices that may be connected to data processing system  1200 . For example, input/output unit  1212  may provide a connection for user input through a keyboard, a mouse, and/or some other suitable input device. Further, input/output unit  1212  may send output to a printer. Display  1214  provides a mechanism to display information to a user. 
     Instructions for the operating system, applications, and/or programs may be located in storage devices  1216 , which are in communication with processor unit  1204  through communications framework  1202 . The processes of the different embodiments may be performed by processor unit  1204  using computer-implemented instructions, which may be located in a memory, such as memory  1206 . 
     These instructions are referred to as program code, computer usable program code, or computer readable program code that may be read and executed by a processor in processor unit  1204 . The program code in the different embodiments may be embodied on different physical or computer readable storage media, such as memory  1206  or persistent storage  1208 . 
     Program code  1218  is located in a functional form on computer readable media  1220  that is selectively removable and may be loaded onto or transferred to data processing system  1200  for execution by processor unit  1204 . Program code  1218  and computer readable media  1220  form computer program product  1222  in these illustrative examples. In one example, computer readable media  1220  may be computer readable storage media  1224  or computer readable signal media  1226 . In these illustrative examples, computer readable storage media  1224  is a physical or tangible storage device used to store program code  1218  rather than a medium that propagates or transmits program code  1218 . 
     Alternatively, program code  1218  may be transferred to data processing system  1200  using computer readable signal media  1226 . Computer readable signal media  1226  may be, for example, a propagated data signal containing program code  1218 . For example, computer readable signal media  1226  may be an electromagnetic signal, an optical signal, and/or any other suitable type of signal. These signals may be transmitted over communications links, such as wireless communications links, optical fiber cable, coaxial cable, a wire, and/or any other suitable type of communications link. 
     The different components illustrated for data processing system  1200  are not meant to provide architectural limitations to the manner in which different embodiments may be implemented. The different illustrative embodiments may be implemented in a data processing system including components in addition to and/or in place of those illustrated for data processing system  1200 . Other components shown in  FIG. 12  can be varied from the illustrative examples shown. The different embodiments may be implemented using any hardware device or system capable of running program code  1218 . 
     Thus, the illustrative embodiments provide a method and apparatus for assisting an operator in managing the operation of aircraft. In particular, the illustrative embodiments may be applied to managing unmanned aerial vehicles. Flight information for unmanned aerial vehicles is presented on a timeline using symbols from a top-down view. The commonality of symbols between the top-down view and the timeline view assists the operator in more quickly viewing flight information displayed on these views. In this manner, an operator may manage unmanned aerial vehicles with less fatigue, manage more unmanned aerial vehicles at the same time, perform other operations, or some combination thereof. 
     The description of the different illustrative embodiments has been presented for purposes of illustration and description and is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different illustrative embodiments may provide different features as compared to other illustrative embodiments. The embodiment or embodiments selected are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.