Abstract:
A system for supervising the landing of an aircraft by a supervisor in a control station, each of the aircraft being incapable of being controlled by any personnel onboard, the system comprises a control station and onboard aircraft control apparatus. The station includes an input device, responsive to the supervisor, for producing a control signal for controlling the landing of the aircraft; and a transmitting device, coupled to the input device, for communication with the aircraft. The aircraft apparatus includes a receiving device for communication with the station; a logic device, coupled to the receiving device, for controlling the aircraft which is programmed to pilot the aircraft to the vicinity of the airfield. The control signal is selected by the supervisor, based on the supervisor&#39;s observations of the aircraft and is transmitted to the logic device; in response thereto, the logic device controls the aircraft.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application incorporates by reference U.S. Pat. No. 6,917,863 and each of U.S. patent application Ser. Nos. 10/919,169, 11/373,712, 11/385,270 and 11/388,311. 
     BACKGROUND OF THE INVENTION 
     The inventions herein concern the air traffic (and associated ground aircraft traffic) management for
     a) hijacked aircraft;   b) aircraft in which an impaired pilot or pilots is/are no longer capable of flying the aircraft;   c) airfields used by unmanned aerial vehicles;   d) airfields not manned by an air traffic controller;   e) airfields and aircraft with capable onboard pilots wherein, for reasons discussed hereinbelow it may be desirable to have a supervisor or a computational device (also referred to as “logic device”) controlling a landing and/or takeoff; and   f) combinations of a)-e).   

     Emphasis is placed on the management of hijacked aircraft in which control has been taken away from the onboard pilot, as discussed in U.S. Pat. No. 6,917,863 and other referenced patents and applications. Nevertheless, it will be clear that the operating principles for other remotely controlled or controllable aircraft are parallel in nature—or identical. 
     One way of maximizing security for the above-referenced hijacking prevention system is to minimize the opportunity for an outside, ill-intentioned agent to gain (or attempt to gain) control over a remotely controlled aircraft. Parameters which may be minimized are: 
     a) the amount of information which the remotely guided aircraft can receive; 
     b) the total time during which remote guidance is allowed; and 
     c) the distance over which such information is transmitted. 
     Methods c) of minimizing the distance over which information is transmitted include the use of an interceptor aircraft, and the use of a high output transmitter to transmit commands and a low sensitivity receiver. These are discussed in the U.S. Pat. No. 6,917,863 and in application Ser. No. 10/919,169. 
     Other methods techniques for minimizing interference include the use of highly directional signal transmission, and encoding and encryption techniques, also discussed in U.S. Pat. No. 6,917,863 and in application Ser. No. 10/919,169. 
     Considering a) and b) above: 
     The theoretic extreme case is one in which there is no remote guidance whatsoever, i.e. in which the flight, from the time of button press until the time of landing, runs entirely on autopilot. The problems with such a system are: 
     a) inability to navigate around bad weather en-route to the secure airfield (SAF); 
     b) inability to make last minute corrections due to unanticipated turbulence, microbursts, wind shear or other unfavorable conditions in the vicinity of the secure airfield; and 
     c) the fact that the system can be defeated by hijacking multiple aircraft at around the same time and flooding the secure field with arrivals. Two aircraft attempting to land simultaneously, both with essentially identical glide paths, runway assignments and arrival times would collide. 
     SUMMARY OF THE INVENTION 
     The present invention discusses methods and systems of remote guidance in which the amount of information exchanged between the hijacked aircraft and an outside source of guidance is minimized. 
     Possible techniques: 
     Technique #1) At the time of button press (BP) a hijacked aircraft (HAC) is assigned: 
     a) a SAF 
     b) a runway at the SAF; 
     c) an approach vector (AV), i.e. a direction (e.g. one of eight compass points) from which it approaches the parking orbit (PO); 
     d) a unique PO, i.e. a circular (or elliptical) orbit, in the vicinity of the SAF; The PO is identified by the coordinates of its center, its radius and its altitude; (or, in the case of an elliptical orbit, the coordinates of the two centers, and the length of each of the semi-major and semi-minor axis; and its altitude) and 
     e) a semi-unique landing time. 
     Systems aboard the HAC, at the time of BP, determine the nearest SAF, calculate the expected arrival time at the SAF, add some pre-determined safety margin, and assign a landing time which is the expected arrival time plus the predetermined safety margin. They also assign the runway, glide path and PO. 
     On arrival at the vicinity of the SAF, the HAC approaches via the direction corresponding to the AV and enters the assigned PO. The determination of last orbit in the parking pattern occurs automatically, so that the deviation from the assigned landing time is minimized. After the last orbit, the HAC moves from PO to the glide path (GP) for the assigned runway and lands UNLESS the HAC receives a “landing inhibit” (LI) signal. The LI signal would be sent only if another aircraft was approaching the same runway or glide path at the same time. The LI signal would cause the HAC to remain in the PO for one more orbit. The HAC would land after the additional orbit, unless it receives another LI signal. 
     Using Technique #1, an HAC can land: 
     a) in an extreme case, without receiving any remote guidance; and 
     b) in a less extreme case, having its only guidance consist of one or more LI signals. The advantage of this approach over that delineated in issued U.S. Pat. No. 6,917,863 and over U.S. patent application Ser. No. 10/919,169 is that the amount of information sent to the HAC, the LI signal, is far less than the amount of information that contains a full set of moment to moment landing commands. The duration of transmission is obviously also far shorter in the case of the LI signal. 
     The LI signal would ideally be sent from a nearby interceptor aircraft (IAC). Alternatively, the LI signal could be sent from a control tower, a satellite, or a remote control center (RCC) which is not in the vicinity of the SAF. Approaches to the prevention of hacking of the LI signal would be the same as those employed for the prevention of hacking in general, i.e. short range transmissions with high directionality. The advantage of the Technique #1 is that the total time of signal transmission to the HAC is very short (and possibly zero), and the information content is very small. 
     The flight management systems of potential HACs would be set up to assign semi-unique landing parameters. For example: 
     Aircraft #XXX might be assigned to runway  2 , landing time the nearest to target time of 10, 30 or 50 minutes after the hour; 
     Aircraft #YYY might be assigned to runway  2 , landing time the nearest to target time of 0, 20 or 40 minutes after the hour; 
     Aircraft #ZZZ might be assigned to runway  1 , landing time the nearest to target time of 10, 30 or 50 minutes after the hour; etc. 
     These assignments could not be entirely unique, since uniqueness would require one SAF/runway/time assignment for each aircraft currently in the air—an impossibility. But the availability of P runways and Q landing times at a particular SAF would mean that the chance of a duplicate assignment of two randomly assigned aircraft is 1/PQ. And, importantly, the case of possible duplication of assigned runway and landing time is dealt with by the possibility of temporarily inhibiting a landing by a LI signal. 
     The capacity of each SAF is increased by the parking orbits. One stack of POs, with equal radius and identical center points, with aircraft situated every 1000 feet of altitude from 1000 to four thousand feet would accommodate four aircraft, and thereby increase the capacity of a runway by a factor of four. Additional increases in capacity could be achieved by: 
     a) having each stack have POs with more than one radius (e.g. an 8 mile and a 12 mile radius); and 
     b) having multiple stacks with different center points (e.g. one to the east of the runway, and one to the west). 
     Obviously, stack geometry would have to be such that no overlap of orbits between stacks is possible. 
     For J Stacks per runway, each stack having K orbits, at an SAF with P runways, the number of possible orbiting aircraft could be as many as JKP, i.e. J times K times P. For example, a SAF using 2 stacks, each having 4 orbits, for each of 3 runways, could have 24 orbiting aircraft at any one time. 
     Even so, there is the possibility that random assignment of a PO may result in an identical assignment for two HACs, in the case of multiple hijackings. In the aforementioned example of a SAF with 24 possible POs: 
     a) the chance that two randomly assigned simultaneously arriving HACs would have the same PO would be 1/24; and 
     b) the chance that three randomly assigned simultaneously arriving HACs would have a duplicate or triplicate assignment would be 35/288 (approximately 12%). 
     To deal with this possibility, a “change parking orbit assignment” (CPOA) signal could be sent. The source of the signal would be the same as the source of the LI signal. There are a number of possible CPOA signal formats: 
     a) All of the POs at a SAF could be numbered. A CPOA signal of the first type (CPOA- 1 ) would cause the HAC to approach the PO with the PO identification number which is one greater than the initial assignment. Two consecutive CPOA- 1  signals would cause the HAC to approach the PO with the PO number which is two greater than the initially assigned PO; 
     b) Alternatively, or in addition, a CPOA- 2  signal could be a command to enter the PO with the PO identification number which is one less than the initial assignment. (In the case of a SAF with 24 possible POs, a CPOA- 2  signal would accomplish what 23 consecutive CPOA- 1  signals accomplishes.) Two consecutive CPOA- 2  signals would cause the HAC to approach the PO with the PO identification number which is two less than the initially assigned PO. 
     c) Alternatively, or in addition a CPOA- 3  (CPOA- 4 ) signal could cause the HAC to be reassigned to the PO which has an altitude 1000 feet greater (or lower, in the case of CPOA- 4 ) than that of the initially assigned PO; 
     d) Alternatively, or in addition a CPOA- 5  signal could cause the HAC to be reassigned to a PO in a different stack, with an altitude identical to the initially assigned PO; 
     e) Alternatively, a CPOA- 6  signal could specify exactly which of the numbered POs is to be switched to; (In the case of the above example, there would be 24 possible CPOA- 6  signals; and 
     f) Alternatively, a CPOA- 7  signal could specify the geometry of a not previously delineated PO, i.e. it&#39;s center (centers in the case of an elliptical orbit), radius (radii in the case of an elliptical orbit) and altitude. 
     The need for a CPOA signal would be based on the knowledge that two HACs are headed for the same PO. Such knowledge could be obtained: 
     a) by visual means: e.g. a person aboard an IAC sees that HAC # 1  and HAC # 2  are headed for the same PO; 
     b) by electronic means, i.e.
         i) a person aboard an IAC can interrogate an approaching HAC by sending a signal which causes the HAC to transmit its intended PO to the IAC: or   ii) the HAC automatically transmits a signal which indicates its intended PO, on approach to the SAF.       

     A method of automatically assigning POs, for systems which allow transmission of PO assignment signals [such as in the case of b) ii) immediately above], would be: 
     a) Each PO is numbered, and each HAC occupying a particular PO transmits a signal which indicates that that particular PO is occupied, a POO signal (In the above example, there would be 24 types of POO signals.); 
     b) A HAC approaching an SAF receives each of the POO signals and assigns itself to an unoccupied PO; and 
     c) That HAC starts transmitting a POO signal corresponding to its particular PO. 
     Each of the concepts involved in collision avoidance in or near a PO due to “overbooking” of POs could be used for the AV to a PO. AVs could be numbered and policed by either IACs, or distant remotely located pilots. Alternatively, an automatic collision avoidance system for the AVs, with characteristics similar to that described hereinabove for the POs could be operative. Such a system would have “change approach vector assignment” (CAVA) signals analogous to the CPOA signals described hereinabove. 
     The collision avoidance systems for the POs and for the AVs would require autopilot/flight management computer programs aboard the HAC which allow it to make a transition from one particular PO to another and/or from one particular AV to another. 
     In summary, Technique #1 involves the minimization of communication with the HAC by using an automated landing which uses a LI signal, if necessary. Variations of Technique #1 involve: 
     a) the use of CPOA signals; 
     b) the use of CAVA signals; and 
     c) the use of signals from the HAC which indicate actual or intended PO occupation. 
     Hybrids of the aforementioned Technique #1 and the ‘Methods’ of U.S. Pat. No. 6,917,863 and, Ser. No. 10/919,169 involve using Technique #1 until some very late point in the approach to the runway, and then, for the last very short segment (e.g. 10 to 60 seconds) using an off-aircraft pilot (aboard an interceptor aircraft or ground-based) for the landing. 
     Technique #2 is similar to technique #1 except that in the case of Technique #2, there is no assignment of a landing time. Instead, the HAC waits in its assigned PO until it receives a landing confirmation (LC) signal from either an IAC or an alternatively located controller. 
     Technique #2) At the time of button press (BP) a hijacked aircraft (HAC) is assigned:
         a) a SAF   b) a runway at the SAF;   c) an approach vector (AV), i.e. a direction (e.g. one of eight compass points) from which it approaches the parking orbit (PO); and   d) a unique PO, i.e. a circular (or elliptical) orbit, in the vicinity of the SAF; The PO is identified by the coordinates of its center, its radius and its altitude; (or, in the case of an elliptical orbit, the coordinates of the two centers, and the length of each of the semi-major and semi-minor axis; and its altitude).       

     The IAC (or alternative) controller (“the controller”) then selects a particular HAC for landing based on the controller&#39;s estimate of the priority of each HAC (which may be based on an estimate of the remaining fuel and of the urgency of the situation within the HAC). The controller then sends a LC signal to the HAC most in need of immediate landing. 
     Variations of Technique #2 involve: 
     a) each of the variations indicated for Technique #1 and 
     b) variations in which the controller transmits runway selection information including:
         i) runway assignment, for a system in which there is no initial runway assignment; and   ii) change of runway assignment, for a system in which there is initial runway assignment, but where the initial runway assignment is deemed to be unsatisfactory;       

     c) systems which involve an initial semi-unique landing time assignment, and a LI signal and a LC signal. In this case, the technique is similar to Technique #1 until the LI signal is sent. Thereafter, the HAC remains in the PO until a LC signal is sent to it; and 
     d) hybrids with U.S. Pat. No. 6,917,863 and. Ser. No. 10/919,169, in which the approach to the SAF is as indicated herein, but in which the last 10 to 60 seconds of the landing of the HAC are fully controlled by a remote pilot. 
     Other variations on the aforementioned Technique #1 and #2 include: 
     a) systems in which the HAC may receive signals enroute to the SAF to either speed up or slow down, based on the anticipated traffic pattern at the SAF, in the event of multiple hijackings. In a preferred embodiment of the invention such signals would originate from a nearby source, e.g. a nearby interceptor aircraft, using the aforementioned signal security techniques. 
     b) systems in which, on arrival at the PO, the aircraft speed is either:
         i) pre-programmed;   ii) transmitted to the HAC by a signal from a controller; or   iii) in a “no-controller” system, selected by equipment onboard the HAC;       

     c) systems in which two or more aircraft occupy the same PO (e.g. separate by 180 degrees in a circular orbit). In such cases, care would need to be taken to assure that:
         i) the aircraft in a shared PO each had the same speed;   ii) the aircraft, because of small speed variations were not drifting towards each other; and   iii) that various collision avoidance procedures could be immediately implemented if necessary including (a) a LC signal, or (b) a signal to change speed. The source of such a signal could be the controller, or a collision avoidance system on the HAC;       

     d) systems in which the approaching or orbiting aircraft transmits information to an the controller about the quantity of it&#39;s remaining fuel supply/amount of remaining fly-time before fuel dissipation. The controller then selects a particular HAC for landing based on the controller&#39;s estimate of the priority of each HAC (which may be based on the transmitted information about the amount of remaining fuel [and of the urgency of the situation within the HAC]).
         i) In Technique #2, the controller then sends a LC signal to the aircraft most in need of immediate landing. The controller may also send one or more LI signals to aircraft with greater fuel reserves, if these aircraft were scheduled for landing at the time now re-assigned to a low fuel aircraft;   ii) In Technique #1, the controller may select which of two or more aircraft (scheduled to land approximately simultaneously) to send a LI signal to based on the transmitted remaining fuel information from each.       

     The controller could also send a CPOA signal to an aircraft with a low fuel situation, assigning it to an orbit which is either smaller, nearer the runway, lower in altitude or populated by one or more other low velocity aircraft; and 
     e) systems in which the approaching or orbiting aircraft transmit information to each other about the quantity of remaining fuel supply/amount of remaining fly-time before fuel dissipation for each aircraft. Each aircraft then is assigned a priority number for landing, based on the remaining fuel/fly-time. The assignment of priority number is by equipment that may be on some or all of the aircraft. The priority numbers may be updated and, if necessary, changed (by the same system that initially assigned them), as the minutes go by before actual landing. The remaining fuel/fly-time determination information may also be used to assign either a lower altitude or lower speed PO, or a PO nearer to the runway. 
     The aforementioned approaches: 
     a) minimize the opportunities for hacking by an unauthorized person; 
     b) minimize the opportunities for “jamming” remote pilot/controller signals by an unauthorized person. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a block diagram of a supervisor-controlled system for landing a plurality of aircraft on which no onboard person controls the aircraft. 
         FIG. 1B  shows a block diagram of a supervisor-controlled system for landing a plurality of aircraft on which no onboard person controls the aircraft, and in which one or more aircraft may have been controlled by an off-aircraft pilot. 
         FIG. 2A  shows a block diagram of an automatically controlled system for landing a plurality of aircraft on which no onboard person controls the aircraft. 
         FIG. 2B  shows an automatically controlled system for landing a plurality of aircraft on which no onboard person controls the aircraft, and in which one or more aircraft may have been controlled by an off-aircraft pilot. 
         FIG. 3A  shows a block diagram of an automatically controlled system for supervising the landing of a plurality of aircraft on which an onboard person controls the aircraft. 
         FIG. 3B  shows a block diagram of an automatically controlled system for controlling the landing of a plurality of aircraft on which an onboard person may share control of the aircraft. 
         FIG. 4  shows one configuration of parking orbits in the vicinity of a runway. 
         FIG. 5A  shows a block diagram of control station transmitting equipment and transmitted signals, for a supervisor-controlled landing management system. 
         FIG. 5B  shows a block diagram of control station transmitting equipment and transmitted signals, for a landing management system controlled by a logic device. 
         FIG. 6  shows a block diagram of aircraft receiving apparatus and received signals, for one embodiment of the landing management system. 
         FIG. 7  shows a block diagram of aircraft transmitting apparatus and transmitted signals, for one embodiment of the landing management system 
         FIG. 8A  shows a block diagram of control station receiving equipment and received signals, for a supervisor-controlled landing management system. 
         FIG. 8B  shows a block diagram of control station receiving equipment and received signals, for a landing management system controlled by a logic device. 
         FIG. 9  shows a block diagram of a system which has the capacity to function as both an automated landing system for a particular individual aircraft, and as the controller of a complete automated landing system. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1A  shows a preferred embodiment of the invention for use with an aircraft which contains apparatus which locks onboard personnel out of control because of a hijacking. The lockout may occur when an onboard person becomes aware of the hijacking and activates the lockout system using input device  2 .  2  may be a button which is pressed, a keyboard for issuing a command, a speech detecting apparatus which detects critical command words, etc. Other more sophisticated system activating approaches are discussed in U.S. Pat. No. 6,917,863 and are known in the art. The lockout may also occur when an off-aircraft person activates the system (see below). 
     The lockout command causes logic device  3  to:
     a) prevent the onboard pilot from using controls  4  to control critical items such as each of the moveable surfaces  5 , throttles  6 , landing gear  7  and brakes  8 ; and   b) issue commands to each of  5 , and  6  (and to any other onboard apparatus necessary for control of the aircraft) to fly the aircraft to the vicinity of an airfield at which a landing is desired.   

       3  contains memory apparatus  9 , which includes instructions which allow the aircraft to fly to a desired location in the event of the aforesaid emergency. These instructions may include the coordinates of the target airfield, the coordinates of one or more waypoints, the altitude for each portion of the route, the speed for each portion of the route, the approach vector for the target airfield, information concerning orbiting or loitering in the vicinity of the target airfield, the target runway choice, airfield destination time, the coordinates of one or more secondary/alternative airfield choices and criteria for selecting such alternative choices, and other items as are known in the art. The instructions may be programmed into  9  using conventional programming techniques for a convention re-writable memory. Alternatively, the instructions may be written into a write-once-only memory such as a PROM, an EPROM, and EEPROM and other devices as are known in the art. Alternatively, such instructions may be transmitted to the aircraft—either in part or completely during the flight (via receiver  16 ). 
       3  may include at least one autopilot and may include at least one flight management computer. In a “fly-by-wire” aircraft,  3  may be entirely electronic, i.e. contain no moving parts.  3  may be a single electronic device which incorporates the features of autopilot(s) and flight management computer(s) and hijacking management computers and/or circuitry. Alternatively, especially in a non-fly-by-wire vehicle,  3  may contain one or more moving parts which allow for the interruption (likely an irreversible interruption) of one or more mechanical linkages between the onboard pilot controls  4  and the controlled items  5 - 8 . 
     In the vicinity of the target airfield, the intervention of a human supervisor may be desirable. This would be the case, for example, if multiple aircraft were hijacked and were headed automatically for the same airfield at approximately the same time. It would also be desirable if the target airfield had adverse weather conditions. It would also be desirable if the aircraft was damaged, so that its automated control systems were incapable of adequately controlling it. 
       FIG. 1A  shows the system with which supervisor  10  in a control station  11  controls the landing of an aircraft containing aircraft control apparatus  12 .  10  uses input device  13  to send one or more control signals  14  to transmitting device  15 .  15  transmits the at least one signal to receiving device  16  aboard the aircraft. 
     Possible signals  14  (as discussed hereinabove) which could be selected and sent by  10  include (a) a LI signal, (b) a LC signal, (c) a CAVA signal, (d) a CPOA signal, (e) a runway assignment signal, (f) a signal indicating landing time, (g) a signal indicating taxiways, (h) a signal indicating a particular approach vector, (i) a signal indicating a particular parking orbit, and (j) a signal indicating aircraft velocity. 
     The basis for selecting one or more such signals may be visual sighting of the aircraft, or detection by radar. Information which does not originate on the aircraft which is to land is referred to collectively as  17  in the figure;  17  may also include apparatus for displaying said information. Alternatively, information may originate on the aircraft: 
     a) In one embodiment, telemetry device  18  may send telemetry information to aircraft transmitter  19 ; the information is received by control station receiver  20  and displayed for  10  on display device  21 . Telemetry information may include (i) the aircraft identification, (ii) the amount of remaining fuel, (iii) aircraft coordinates based on GPS, (iv) aircraft altitude; (v) aircraft velocity; (vi) oil pressure and/or temperature; (vi) information about landing gear position and functioning, and (vii) information about the integrity of various mission critical components and their functioning. The telemetry information may be used to calculate the remaining available fly-time, given the remaining amount of fuel. This information, as well as the other aforementioned telemetered information may be used by  10  to prioritize landing in the event that multiple vehicles are headed for a simultaneous or near simultaneous landing. 
     b) In another embodiment, landing parameter information stored in  9  (such as preprogrammed runway assignment) may be communicated to  10  by sending signals from  9  to  19  to  20  to  21 . Such signals may be sent (a) intermittently, (b) only as the aircraft approaches the airfield, or (c) only by a properly coded and formatted request signal sent by  10  (from  13  to  15  to  16  to  3  to  9 ). 
     All signals exchanged would be encrypted, and encoded as per the state of the art. Additional signal security means are discussed in U.S. Pat. No. 6,917,863 including the combination of a high output transmitter  15  and low sensitivity receiver  16 , highly directional signal transmission; and frequency hopping and other measures known in the art. 
     The description of the apparatus shown in  FIG. 1A  and its operating principles could also pertain to: 
     (a) an unmanned aerial vehicle (UAV) or unmanned aerial system (UAS) [each, hereinbelow, referred to as “UAV”]; The UAV case is discussed hereinbelow, in conjunction with  FIG. 1B ; and 
     (b) an aircraft with a human pilot which is not hijacked. One such situation is that of an injured or impaired pilot incapable of flying the aircraft. Another such situation involves an approach to air traffic management in which the onboard pilot voluntarily cedes control of the aircraft when landing; This could be desirable in situations in which there is extreme congestion in the vicinity of the airfield, or in which the vicinity of the airfield contains one or more highly secure/sensitive items. In this case, the pilot would activate the system using  2 , analogous to system activation in the event of a hijacking.  2 , in this case, would signal  3  to allow landing control by signals  14  received by  16 . 
       11  may be a ground station, an airborne station, a water-based station, a space based station. 
       FIG. 1B  shows an embodiment of the invention in which the aircraft containing apparatus  12  is piloted and/or controlled by an off-aircraft pilot  30  at one or more times during the course of a flight. One example of such a flight would be that of a UAV. In this case, UAV pilot  30 , located at  34 , sends UAV control signals  33  to the aircraft along the path  30  to input device  31  to transmitter  32  to aircraft receiver  16 . All other elements shown in  FIG. 1B  have the same function as those elements with identical element numbers shown in  FIG. 1A . 
     The desirability of ceding control of a UAV to a supervisor in the vicinity of an airfield may increase as the number of UAVs increases. Increasing UAV congestion, the lesser extent of UAV pilot training and regulation compared to commercial and passenger pilots, the lesser extent of UAV reliability compared to commercial and passenger air vehicles, the greater susceptibility to weather-induced aerodynamic complexities, and the smaller UAV fuel capacity compared to non-UAV aircraft, are all factors which will make desirable a means of integrated airfield control, when UAV landings are involved. Furthermore, in an airspace or at an airfield where both UAVs and non-UAV (i.e. manned) aircraft fly, the tolerance for anomalous or sub-optimal UAV behavior will be markedly decreased—also thereby increasing the desirability of a system such as that of the invention shown in  FIG. 1B . 
     The UAV pilot would transfer control to  10  by sending a control transfer signal (one type of  33 ) to  3  via  32  and  16 . Such a signal would enable control of the UAV by  10 . In an alternate embodiment of the invention, the transfer of control of elements  3 ,  5 ,  6 ,  7  and  8  within apparatus  12  aboard the UAV could be, by statute, mandatory, which allows a properly identified  10  to take control of the UAV in the vicinity of an airfield or other location in which a high degree of safety and security are mandatory. 
     In one embodiment of the invention for UAV use,  34  may also contain a receiver (not shown) attached to a display device (not shown) for receiving telemetry and other information from  12 , transmitted by  19 . 
       FIG. 1B  also shows the arrangement in which Remote Initiated Takeover (RITO) occurs, as discussed in U.S. Pat. No. 6,917,863 and U.S. patent application Ser. Nos. 10/919,169 and 11/388,311. In such a hijacking or emergency situation, an off aircraft supervisor  30  may trigger a takeover, e.g. if he becomes aware of a hijacking or emergency that onboard personnel are not capable of communicating. 
       FIG. 2A  shows an embodiment of the invention for dealing with hijacked aircraft, aircraft with impaired pilots and UAVs in which the supervisor  30  is replaced by a logic device  40  in control station  42 . The logic device performs all of the functions of the supervisor discussed hereinabove. In addition, transmitter  15  and receiver  20  are replaced in  FIG. 2A  by transmitting/receiving (T/R) device  41 , and, transmitter  19  and receiver  16  are replaced in  FIG. 2A  by transmitting/receiving (T/R) device  44 , within aircraft control apparatus  43 . Decisions may be made by  40  using algorithms stored therein. Decisions may be based on (a) aircraft identification, communicated by  18  to  44  to  41  to  40 ; (b) other aircraft telemetry signals as discussed hereinabove, and communicated by the same path as the aircraft ID hereinabove; and (c) previously stored landing parameter information (as discussed hereinabove) along the path  9  (within  3 ) to  44  to  41  to  40 .  40  may be one computer, a group of computers, a part of one computer, or a part of multiple computational devices.  42  may be a ground station, an airborne station, a water-based station, a space based station. In addition,  42  may be located on one or more controlled aircraft, as shown in  FIG. 9  hereinbelow. In such a case  41  would link  40  to units  44  (and to the elements coupled to  44 ) on other aircraft, but  40  would not need an RF link in order to exchange signals with  3  and/or  18  on its particular aircraft—i.e. the on-aircraft connection between  40  and  3 , and between  40  and  18  could be hard-wired. 
     In one embodiment of the invention, a supervisor would over-read the decisions of  40 . If desired the supervisor could negate them, or provide alternative decisions. The apparatus for such a hybrid control station would require the hardware that comprises  42 , as well as elements  13  and, preferably  21  of element  11  in  FIG. 1A . In addition, switching means (not shown in the figure), under control of the supervisor, would be required to assure that—in the case of  30  overruling  40 —the signal source was  14  (i.e. supervisor signals) and not  45  (i.e. logic device signals). In yet another embodiment of the invention a hybrid control station with both supervisor  30  and logic device  40  may be configured so that  40  warns  30  in the event of a decision made by  30  which may have adverse or unexpected consequences. In still another embodiment of the invention,  40  may overrule  30 , with switching means configured to give control to  40  (over  30 ), if necessary. 
     In the case of the hybrid device, the control station may be reduced to a handheld communications device including a suitably modified cellular telephone or Blackberry device or the like. 
       FIG. 2B  shows an embodiment of the invention in which the aircraft containing apparatus  46  is piloted and/or controlled by an off-aircraft pilot  50  at one or more times during the course of a flight. One example of such a flight would be that of a UAV. In this case, UAV pilot  50 , located at  54 , sends UAV control signals  53  to the aircraft along the path  50  to input device  51  to transmitter  52  to aircraft receiver  16 . All other elements shown in  FIG. 2B  have the same function as their counterparts in  FIG. 2A . As was the case with the embodiment described by  FIG. 1B ,  FIG. 2B  may also pertain to (a) a RITO situation; and (b) an embodiment in which  54  also includes a receiving device and a display device. 
       FIGS. 3A and 3B  pertain to an aircraft with an onboard pilot whose motion in the vicinity of an airfield is to be controlled by a logic device  60 . Such motion includes landings, takeoffs and motion within an airport. Such apparatus would be useful: (a) in a small airport which does not have an air traffic controller; (b) in an airport where the number of air traffic controllers at any one time is insufficient to handle the load; (c) as a mobile, freestanding and/or backup device, in the event of damage to some or all of the equipment in an air traffic control center. 
       FIG. 3A  shows an embodiment of the invention in which traffic control instructions outputting from  60  constitute recommendations, which the onboard pilot is advised to carry out.  FIG. 3B  shows an embodiment of the invention in which the traffic control instructions are carried out automatically. 
     Referring to  FIG. 3A , logic device  60  in control station  62  receives incoming information from aircraft apparatus  63  along the path  65  (aircraft telemetry device) to  64  (aircraft transceiver) to  61  (control station transceiver) to  60 . It sends traffic control recommendations to display device  66  aboard the aircraft along the path  60  to  61  to  64  to  66 . 
     Referring to  FIG. 3B , there are structural and functional parallels to the apparatus shown in  FIG. 2A  (with exceptions to be discussed). Control signals sent to aircraft apparatus  73  from control station  62  are along the path  60  to  61  to  67  (aircraft transceiver) to  68  (aircraft logic device) to controlled items  5 - 8 . Aircraft information sent to  60  includes telemetry  70 , along the path  70  to  67  to  61  to  60 . In an embodiment of the invention in which the landing parameters are stored within  69 , they may be sent along the path  68  to  67  to  61  to  60 . 
     In one embodiment of the invention shown in  FIG. 3B , the onboard pilot would have no say in the enactment of the air traffic instructions. In another embodiment, the onboard pilot would have to enable remote instruction inputting via input device  71 . The onboard pilot could also be given the opportunity to override remote instructions—overriding either a single instruction, multiple instructions or all instructions, using input device  72 .  71  and  72  communicate the aforementioned pilot decisions—if such decisions are system options—to logic device  68 . 
     As discussed in conjunction with  FIG. 2A , embodiments of the invention in which a hybrid system includes both a supervisor (not shown in the figure) and associated input and display apparatus, and a controller are possible. Embodiments are possible in which: (a) the supervisor may overrule the logic device; (b) the logic device may overrule the supervisor; and (c) the logic device may make recommendations if the supervisor makes recommendations not considered to be sound, based on the logic device algorithms. 
       FIG. 4  shows one possible configuration of parking orbits in relation to a runway. Aircraft  100  is shown in its final approach to runway  102 . One stack of four parking orbits  104 A-D is shown. Aircraft  106  occupies the highest orbit,  104 A. Aircraft  108  occupies the second lowest orbit  104 C. A second stack of orbits  110 A-D is shown, with aircraft  112  occupying the lowest orbit  110 D. 
       FIG. 5A  shows control station equipment for transmitting signals and signals which are sent by a supervisor, intended to control an aircraft. Each of signals  120 A-H are possible signals which the supervisor may send to the aircraft. The supervisor would input his actions through console  122 A. The signal is encoded at  124 , encrypted at  126  and transmitted at  128 . Embodiments of the invention which use all, some or only one (e.g. the LC signal) of the signals are possible. Embodiments with additional aircraft control signals are possible. Signal  120 H, allows the supervisor to take full control of a hijacked aircraft and remotely fly it as discussed in U.S. Pat. No. 6,917,863. 
       FIG. 5B  shows control station equipment for transmitting signals and signals which are sent by logic device  122 B (as shown in  FIGS. 2A ,  2 B,  3 A and  3 B), intended to control an aircraft. Each of signals  120 A-H are possible signals which the supervisor may send to the aircraft. Other than the substitution of logic device  122 B in  FIG. 5B , for supervisor command console  122 A of  FIG. 5A , the apparatus and its functioning is identical in these two figures. 
       FIG. 6  shows an aircraft receiver and associated components and signals, for receiving the signals sent by the controller transmitter shown in  FIGS. 5A and 5B . Each of the possible received signals  130 A-H corresponds to the possible controller transmitted signals  120 A-H. The signals are received by aircraft receiver  138 . They are decrypted at  136 , and decoded at  134 . Each of  130 A-H is sent to the autopilot/flight management computer/logic device system aboard the aircraft. Embodiments with all, some or only one received signal are possible. 
       FIG. 7  shows the aircraft transmitter and associated components and signals. Each of the possible transmitted signals  140 A-H corresponds to the aircraft information of use to the control station supervisor (or control station logic device). Information from fuel sensor  142  may be transmitted, and may be used along with flight management computer information to compute the estimated amount of remaining fly time for the current fuel supply. The signals are encoded  144 , encrypted  146  and transmitted  148 . Embodiments with all, some, one or no transmitted aircraft signals are possible. 
       FIG. 8A  shows the control station receiver and associated components and signals. Each of the possible received signals  150 A-F corresponds to the signals sent by the aircraft. The signals are received  158 , decrypted  156 , decoded  154  and displayed to a supervisor at  152 A. Embodiments with all, some, one or no received aircraft signals are possible. 
       FIG. 8B  shows control station equipment for receiving signals and signals which are sent to logic device  152 B (as shown in  FIGS. 2A ,  2 B,  3 A and  3 B), instead of being sent to supervisor display  152 A. Each of signals  150 A-F are possible signals which the logic device may use for generating aircraft instructions. Other than the substitution of logic device  152 B in  FIG. 8B , for supervisor command console  152 A of  FIG. 8A , the apparatus and its functioning is identical in these two figures. 
       FIG. 9  shows a system that allows self-management of multiple aircraft without a separately located control station. The control station is replaced by priority management computer  160 . Embodiments of the invention with priority management systems aboard all aircraft or aboard some aircraft are possible. When multiple aircraft each have a priority management computer, the computers may exchange information to select a single computer which remains the dominant computer for as long as a) it is in the airspace near the runway, or b) it is in the vicinity. The dominant computer may be selected based on a) least recent arrival time, b) most recent arrival time, c) other values of arrival time, d) a preset numbering system, such that the computer numbered with the highest number becomes the dominant one, e) combinations of the above, or f) other approaches. 
     The priority management computer (PMC) receives one or more of signals  162 B-H which indicate conditions, previously programmed assignments or other information from each of the aircraft waiting to land. In addition, if a PMC on another aircraft is the dominant one, signals from the PMC  162 A are received and sent to autopilot/flight management computers  164 . Embodiments with fewer or greater numbers of received signals are possible. 
     Each of signals  162 A-H is received by receiver  166 , decrypted  168  and decoded  170 . 
     PMC  160  using information from other aircraft (signals  162 B-H, and information from the aircraft in which it is located (from autopilot/flight management computer  164  and from fuel sensor  174 ) generates a priority list/order for landing ( 172 C), runway assignments  172 C, PO assignments  172 A, and AV assignments  172 B. In cases where these items were previously assigned (either by pre-programmed information, or by earlier PMC assignments), the assignments may be changed or updated. The assignments are encoded  176 , encrypted  178  and transmitted  180 . 
     In the case where the dominant PMC is aboard another aircraft, signals  182 A-G, indicating information pertaining to the aircraft without the dominant PMC are transmitted via  176 ,  178  and  180 . 
     The priority management computer and associated system shown in  FIG. 9  can be used: 
     a) in a non-hijacking situation: 
     i) for managing the landings and approach to landing fields for unmanned aerial vehicles or unmanned aerial systems; 
     ii) for managing airfields in which there is no air traffic controller (ATC); 
     iii) for managing airfields in which there is an ATC, as a backup system for the ATC (or in which the ATC serves as the backup for the invention shown in  FIG. 9 ); and 
     iv) for managing aircraft in which an impaired pilot or pilots cannot safely fly their aircraft; and 
     v) combinations of i), ii), iii) and iv) hereinabove; and 
     b) in a hijacking situation: 
     i) in which multiple aircraft are hijacked and are headed for the same airfield; and 
     ii) for managing airfields in which there are both hijacked aircraft and non-hijacked aircraft needing to land. 
     There has thus been shown and described a novel apparatus for airfield management which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.