GB2479167A

GB2479167A - Air traffic control method for determining a landing order for aircraft

Info

Publication number: GB2479167A
Application number: GB1005405A
Authority: GB
Inventors: Hisashi Manabe
Original assignee: NEC Europe Ltd
Current assignee: NEC Europe Ltd
Priority date: 2010-03-30
Filing date: 2010-03-30
Publication date: 2011-10-05
Also published as: GB201005405D0

Abstract

Disclosed is a method of air traffic control for landing aircraft. A data communication link is established between a aircraft and a control station when the aircraft reaches the perimeter of the control zone of the airport it wishes to land at. The aircraft sends a request message including its' location, such as from a global satellite system to the ground station. The ground control then determines a position for the aircraft in the landing order of the aircraft wanting to land by comparing its' location with the location of the other aircraft and by calculating the arrival time of each aircraft at a common waypoint. The landing order is assigned based on the arrival time. A reply message is then sent to the aircraft containing the coordinates of the waypoint to be passed through prior to landing, and a first unique time to pass through the waypoint to implement the calculated landing order.

Description

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AIR TRAFFIC CONTROL METHOD AND APPARATUS

The present invention relates to a method and apparatus for managing the landing of aircraft in an air traffic control system.

Known air traffic control (ATC) systems are based on radar, which monitors position and other properties of aircraft. Airports typically use airport-surveillance radar (ASR), an S-band radar having a primary surveillance radar coverage of around 50 to 60 nautical miles (NM) (around 90 to 110 kilometres). ASR is a primary radar system which passively tracks (in two dimensions) the range and bearing of target aircraft by detecting reflected radio signals. In addition to ASR, a secondary surveillance radar (SSR) is also used mainly to identify aircraft and to retrieve altitude information by receiving additional information from a transponder activated inside the aircraft which detects incoming radar signals and broadcasts an encoded radio signal.

During flight an aircraft may pass through many different sectors of radar coverage monitored by different centres in the ATC system. In each sector, the centres and aircraft communicate with each other to specify any alterations to a flight plan, for example to move around bad weather or avoid a congested sector. STAR (Standard Terminal Arrival Route) are published procedures followed by aircraft, typically on instrument flight rules (IFR) type flight plans, just before reaching a destination airport. A STAR usually covers between the top of descent up to the final approach to a runway for landing. A typical STAR consists of a set of starting points, called transitions, and a description of routes, typically via waypoints, from each of these transitions to a point near a destination airport. At a certain distance from the destination airport an air traffic controller typically directs all planes to move from high altitudes to low altitudes and merges the descending aircraft into a single file line toward the airport. The controller instructs the aircraft with the necessary changes in heading, speed and altitude, to place the aircraft in line with any other aircraft.

Some ATC systems use Automatic Dependent Surveillance Broadcast (ADS-B) systems in addition to ASR. ADS systems use a Global Navigation Satellite System (GNSS), such as the Global Positioning System (GPS), which provides autonomous geo-spatial positioning to a far greater accuracy than typical radar systems. Aircrafts receive GNSS signals and use them to determine the aircraft's precise position in the sky. In the case of ADS-B, this and other data is broadcast to other aircraft and ATC. The controller can then use the GNSS information in addition to information of ASR.

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Whatever system is used, in high volume traffic conditions the controller may have to place a number of aircraft into a holding pattern, which is a standard route around a given airport.

The aircraft must remain in the holding pattern until the airport can accommodate landing.

Currently, air traffic controllers specify the landing order by monitoring a radar screen containing information on aircraft within a controlling zone.

We have appreciated that holding patterns are undesirable from a fuel cost point of view, as well as an environmental point of view. A reduction in the need for holding patterns will lead to a reduction in C02 emissions from aircraft, as well as saving energy and reducing total flight time.

The invention is defined in the appended claims to which reference is now directed.

Preferred features are set out in the dependent claims.

Embodiments of the present invention provide a method and system for air traffic control that reduces or eliminates the need for holding patterns. This is achieved by specifying, for each aircraft, a different time to pass a specific same waypoint for a landing approach when aircraft reach an edge of a controlled air zone of a landing airport.

Embodiments of the method of air traffic control for landing aircraft involve the step of establishing a communication link, specifically a data communication link rather than a voice communication link, between a first aircraft and a control station when the first aircraft reaches the perimeter of a control zone of a landing airport. A request message is received by the control station from the first aircraft, the request including information determined from a location signal such as a GNSS signal. The control station determines the position of the first aircraft in a landing order, the landing order being the order of landing for a plurality of aircraft, by comparing the location information of the first aircraft with location information from the other aircraft desiring to land. A reply message is sent by the control station to the first aircraft containing the coordinates of a common predetermined waypoint location to be passed through prior to landing, and a first unique time at which to pass through the waypoint to implement the calculated landing order without using holding patterns or requiring excessive detouring.

Embodiments of the system comprise an apparatus for a ground based station and apparatus for an aircraft for implementing a method of air traffic control for landing aircraft.

The apparatus for a ground based station comprises an antenna for receiving request messages from a first aircraft within a control zone, the messages including information determined from a location signal such as a GNSS signaL A memory is provided for storing coordinates of a common predetermined waypoint location to be passed through prior to landing. A landing order analyzer system compares the location information of the first aircraft with location information from a plurality of aircraft and determines the position of the first aircraft in a landing order for the plurality of aircraft and specifies a unique time for the first aircraft to pass through the waypoint to implement the landing order. A transmitter is provided for sending a reply message to each aircraft containing the coordinates of the waypoint and the unique time to pass through the waypoint. The apparatus for an aircraft includes a receiver for receiving location signals, such as GNSS signals and a flight route manager system for inputting data derived from the location signals into the data fields of a request message. A transmitter is included for sending a request message when the aircraft is within a control zone, the request including information determined from a location signal. A receiver is provided for receiving a message from a ground based station containing the coordinates of a common predetermined waypoint to be passed through prior to landing and a unique time at which to pass through the waypoint to implement a landing order. The flight route manager system is configured to send or provide the received coordinates and unique time to a flight controller to adjust the aircraft bearing and speed to reach the waypoint at the specified time.

Embodiments of the present invention will now be described in detail by way of example with reference to the accompanying drawings in which: Figure 1 A is a representation of a landing approach including a holding pattern; Figure 1 B is a representation of a landing approach according to the current invention; Figure 2 is a diagram showing the signals exchanged between the control tower and the aircraft when the current invention is implemented; Figure 3 is a block diagram of a system according to the present invention; and Figure 4 is a diagram showing aircraft routes through a control zone.

Figure 1A shows how aircraft on approach to an airport can be put into a holding pattern I during periods of high volume traffic. Figure 1 B shows how a method according to the invention can be used in which a waypoint 11 is defined for a given runway, being a fixed mid-air location having specific three dimensional coordinates, in a line of landing of the aircraft. The waypoint can be defined using location information extracted from location signals, such as GNSS information extracted from GNSS signals. The time to pass through the waypoint can be assigned on an aircraft by aircraft basis.

Figure 2 shows a number of aircraft in relation to the control zone 24 and a runway of an airport. In the embodiments of the invention described the control zone is a circle centred on the waypoint 23. The aircraft and the control tower (not shown) have a transmitter and a receiver of messages having various information fields. As shown in Figure 2, when an aircraft reaches the edge of the control zone, which is larger than the control zone achievable using ASRJSSR systems, it establishes a data link with an ATC system at the landing airport and sends a request message 21 to the ATC system. The request message contains information fields populated with aircraft information such as aircraft ID, present-location, speed, direction and scheduled arrival time. The ATC system then sends a reply message 22 having information fields containing waypoint information (a fixed single point in the air) such as the location of a waypoint 23, a time (hour, minute, second) to get through the specified waypoint coordinate a speed and a direction or bearing at which to pass through the waypoint 23. The location information provided by the ATC system should be suitable for use with a GNSS system on-board the aircraft, the resolution of the coordinates should therefore allow a GNSS system to identify the waypoint location. The time information should also be provided to a sufficient accuracy to allow landing of aircraft without requiring holding patterns, in particular the timing information should be provided to second order i.e. to an accuracy of the nearest second. As an example, locations are given as a latitude, longitude and altitude; time is specified as year, month, day, hour, minute and second; direction is specified as degree at north, south, east, west and down; and velocity is given as speed in kilometres per hour or a throttle down/back rating.

Once a waypoint location and the time to pass it are specified, the aircraft pilot may then set the auto-aviation system or autopilot to pass through the waypoint 23 at the specified time without holding and/or without excessive detouring by adjusting speed and altitude.

The autopilot may automatically be set in response to the message specifying the waypoint parameters as described below. In the case of manual operation, additional sub-waypoints in the control zone may be specified to navigate to the specific waypoint at a specific time.

To reach the waypoint without flying any extra distance, the control zone of an airport is increased in size. This is achieved by using systems, such as ADS-B, that utilise GNSS information. The appropriate zone size would be different due to peak conditions of each airport but the radius would preferably be between 100NM and I5ONM. Having a larger control zone improves the ability of the ATC system to plan landing orders in advance of landing so as to avoid using holding patterns. Landing order can be manually determined by an air traffic controller when an aircraft reaches an edge of the control zone.

Alternatively landing order can be determined automatically by comparing information from the aircraft request message, such as position (i.e. distance to runway or waypoint), speed and direction. The system can then generate suitable parameters, such as the time for each aircraft to reach a waypoint and speed when passing the specific waypoint in order to safely land each aircraft and avoid using holding patterns.

The ATC system automatically and independently specifies the time to pass through the waypoint. In order to maintain a safe spacing between landing aircraft a predetermined interval, for example 2 minutes, is specified between the times for consecutive aircraft to reach the same waypoint in the air traffic control zone. The time interval between craft can be varied either manually or automatically for given landing scenarios. For example, greater time can be apportioned if a runway is used for both landing and departing or in adverse weather conditions such as heavy fog or snow.

Embodiments of the invention provide for automation of the landing approach procedure.

The ATC system at the landing-airport can inform the auto-aviation or autopilot system of each aircraft directly of the particular waypoint, allowing the auto-aviation system to control the speed and/or direction of the aircraft to get to the waypoint at the specified time. After passing the waypoint, conventional landing guidance systems, such as ILS (Instrument Landing System) or MLS (Microwave Landing System) can be used, either automatically or by being selected by the pilot. The specific waypoint can be specified along a line to the landing runway at a position that, for a given speed, would take the aircraft 1 minute (as an example) to reach a suitable location/distance for using the landing guidance systems.

With reference to Figure 4, an example is provided to illustrate how landing orders are assigned. At a time T0, 4 aircraft (A, B, C, D) reach the edge of the control zone 24. The labels 3Dd(A), 3Dd(B) etc represent the distance over regulated flying routes in the zone, in three dimensional space, of the aircraft to the waypoint 23, For each aircraft the estimated flight time, t(X), to the waypoint 23 is given by the distance 3Dd(X) divided by the speed S(X) predetermined for the landing zone: t(X)=3Dd(X)IS(X) The estimated time to reach the waypoint is therefore, for each of planes A to D: T(A) = T0 + t(A) T(B)=T0+t(B) T(C) = T0 + t(C) T(D)=T0+t(D) The primary landing order is determined by the order from smallest to largest (or earliest to latest) estimated times T(X).

The system also specifies the time (Tw) to reach the specified waypoint 23 by adding time interval tg, which can be varied to make constant intervals among Tw(X)s at the specific waypoint, also depending on factors such as weather conditions and traffic density: Tw(X) = T0 + t(X) +tg(X) Furthermore, if the runway is also being used for aircraft take-offs, an additional time intervall (toff) may be added to allow sufficient time for aircraft to take-off: Tw(X) = T0 + t(X) +tg(X) + toff(X) Finally the landing order system provides specific time Tw(X) to the aircraft. The time Tw(X) indicates the landing order at time Io* When an aircraft receives Tw (X), the pilot (or auto-pilot) adjusts the speed, bearing and altitude of the aircraft to pass through the waypoint at the desired time.

Figure 3 shows a system for implementing embodiments of the present invention comprising an on board unit for an aircraft and a control system to be based on the ground, for example in the air traffic control tower. Both the on board unit and ground based unit comprise a number of components interconnected by a bus system. All components

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connected to the horizontal bus line may communicate with all other components connected to that bus. Each component may optionally be implemented as software running on a computer.

The on-board unit of the aircraft features a GNSS antenna for receiving GNSS signals from orbiting satellites. The GNSS receiver passes GNSS information to the analyzer unit to extract location information. Speed information may be extracted from multiple GNSS signals, or alternatively from on-board instruments.

A route monitor may also be coupled to the GNSS device to cross reference flight plan information with GNSS information. The on board unit also includes an antenna for transmitting and receiving signals, such as radio signals. The antenna is coupled to a receiver and received message analyser, as well as to a transmitter and a message generator.

The transmitter can transmit messages to an ATC system, such as the airport traffic control tower. The message includes information fields to specify aircraft ID, present-location, speed, direction and scheduled arrival time. The receiver can receive messages specifying waypoint information, via the antenna, from an ATC system such as the airport traffic control tower. This waypoint information can be passed to the flight route manager, via the bus system illustrated, to determine the necessary direction and speed to reach the waypoint at the required time, or it can be provided directly to the auto flight controller, which represents the autopilot or auto-aviation system, to control the autopilot system.

The flight route manager is the main control unit for this embodiment of the invention. Its functions include the following: 1) Monitoring the aircraft and determine whether it has entered the control zone or not, based on the location information provided by GNSS.

2) When the aircraft enters the control zone, the flight route manager sets up a data link to communicate with the ground based control tower equipment via the message generator.

3) Once a data link is established, the flight route manager fills out information fields (aircraft ID, present-location, speed, direction and scheduled arrival time) of the message to be sent to the control tower. In order to do so, the flight route manager receives flight data from other on-board equipment including, but not limited to, the functional units shown in Figure 3 through the on-board bus system.

4) When the flight route manager receives a message from the control tower, which message indicates the location of specific waypoint, the time to pass it, the speed at which to pass it, and optionafly the speed and direction to arrive at the desired position and time, the flight route manager arranges the waypoint information in a pre-programmed manner as specified by the pilot. One way to arrange the information is to provide it on the display of the cockpit. An alternative way is providing the waypoint information to the auto-pilot system directly, allowing the aircraft to automatically reach the waypoint without intervention from the pilot.

The control portion of the ATC system, which may be located at the airport traffic control tower, includes an antenna with complimentary receiver and transmitter systems for respectively receiving from and transmitting to different aircraft. The received information can be displayed for an air traffic controller to decipher and to provide aircraft with the appropriate coordinates of a waypoint along with the required speed to pass through the waypoint.

A landing order analyzer receives the information sent by aircraft and contains a processor arranged to calculate the optimum landing order of aircraft within the control zone so as to avoid the need for holding patterns and/or excessive detouring. Landing order can be determined by the landing order analyzer automatically by comparing information such as position (i.e. distance to the specific waypoint), aircraft direction and original landing time, as well as any other factors that may influence the time to reach the waypoint and also the specified time interval between the times for consecutive aircraft to reach the same waypoint to allow take-off at the same runway if it is used for both landing and take-off. The landing order analyzer system can then generate suitable parameters, such as the time and speed for each aircraft to reach the waypoint in order to safely land each aircraft. The landing order analyzer may use information provided by a route monitor that monitors the flight routes in the control zone and progress of aircraft along their routes. The route monitor may be corrected or updated based on information received by the landing order analyzer.

A departing order analyzer is also provided, either as a separate system or integrated with the landing order analyzer, in instances where a runway is used both for landing and take-off. The departing order analyzer uses information provided and updated by ground controllers to analyze anticipated take-off times to make the most efficient use of time between landings. The departing order analyzer can also utilise information from a taxi monitor, which receives and maintains details of aircraft taxiing on the runway or in the vicinity thereof, in order to calculate take-off times based on whether there is sufficient time between aircraft landings. The departing order analyzer communicates with the landing order analyzer and informs the landing order analyzer when an aircraft is due to take off.

The traffic manager sends an appropriate message to the aircraft instructing the position of the waypoint, the time to reach the waypoint and the speed at which to pass through the waypoint. Preferably this information is provided directly to the auto-pilot system of the aircraft, which automatically adjusts the heading and speed of the aircraft as appropriate.

It will be obvious to those skilled in the art that embodiments of the present invention extend beyond the specific embodiments described in the description.

Claims

SCLAIMS1. A method of air traffic control for landing aircraft comprising the steps of: -establishing a data communication link between a first aircraft and a control station when the first aircraft reaches the perimeter of a control zone of a landing airport; -receiving a request message from the first aircraft, the request including information determined from a location signal; -determining a position of the first aircraft in a landing order for a plurality of aircraft by comparing the location information of the first aircraft with location information from the plurality of aircraft; -sending a reply message to the first aircraft containing the coordinates of a common predetermined waypoint location to be passed through prior to landing, and a first unique time at which to pass through the waypoint to implement the calculated landing order.
2. A method according to claim 1 wherein the position of the first aircraft within the landing order is determined by calculating the arrival time of the first aircraft and each of the plurality of aircraft at the common waypoint and assigning the landing order by arrival time.
3. A method according to claim 1 or 2 wherein the information determined from the GNSS signal includes a speed and bearing of the first aircraft.
4. A method according to claim 1, 2 or 3 wherein the reply message also contains a speed at which to pass through the waypoint location.
5. A method according to any preceding claim wherein the waypoint location is colinear with a runway.
6. A method according to any preceding claim wherein the reply message includes instructions to an auto-pilot system indicating the bearing and speed necessary to reach the waypoint at the specified unique time.
7. A method according to claim 6 wherein the reply message causes the auto-pilot system of the first aircraft to be automatically activated.
8. A method according to any preceding claim wherein, after passing the waypoint, a landing guidance system is automatically activated on the first aircraft.
9. A method according to any preceding claim wherein the difference between the first specified unique time and a subsequent specified unique time for a second aircraft, being the aircraft immediately behind the first aircraft in the landing order, is determined so as to allow sufficient time for the first aircraft to land without the second aircraft using a holding pattern or route detour.
10. A method according to claim 9 wherein the difference between the first specified unique time and the subsequent specified unique time is dependent upon whether a target runway is also being used for aircraft take-off.
11. A method according to any preceding claim wherein the location signal is a Global Navigation Satellite System (GNSS) signal.
12. A method according to any preceding claim wherein the coordinates of the waypoint location are based on a GNSS resolution and are suitable for use with a GNSS system.
13. A method according to any preceding claim wherein the first unique time to pass the waypoint is specified to an accuracy of the nearest second.
14. An apparatus for a ground based station for implementing a method of air traffic control for landing aircraft comprising: -an antenna for receiving request messages from a first aircraft within a control zone including information determined from a location signal; -a memory for storing coordinates of a common predetermined waypoint location to be passed through prior to landing; -a landing order analyzer system for comparing the location information of the first aircraft with location information from a plurality of aircraft and determining a position of the first aircraft in a landing order for the plurality of aircraft and specifying a unique time for the first aircraft to pass through the waypoint to implement the landing order; -a transmitter for sending a reply message to specific aircraft containing the coordinates of the waypoint and the unique time to pass through the waypoint.
15. An apparatus according to claim 14 wherein the landing order analyzer is coupled to a route monitor that monitors the routes of aircraft in the control zone and the progress of aircraft along the routes, the landing order analyzer using information provided by the route monitor to determine the position of the first aircraft in the landing order for the plurality of aircraft.
16. An apparatus according to claim 14 or 15 wherein the landing order analyzer system is configured such that the difference between the unique time specified for the first aircraft to pass through the waypoint and the subsequent specified unique time for a second aircraft immediately behind the first aircraft in the landing order is determined so as to allow sufficient time for the first aircraft to land without the second aircraft using a holding pattern or route detour.
17. An apparatus according to claim 14, 15 or 16 wherein the apparatus further comprises a departing order analyzer system that uses information provided and updated by ground controllers to determine anticipated take-off times of aircraft and provides this information to the landing order analyzer system; the landing order analyzer system being further configured to determine the time specified for the first plane to pass through the waypoint based on the information received from the departing order analyzer.
18. An apparatus according to claim 17 further comprising a taxi monitor system, for receiving and storing details of aircraft taxiing on the runway or in the vicinity thereof, the departing order analyzer system being coupled to the landing order analyzer system to provide information thereto.
19. An apparatus for an aircraft for implementing a method of air traffic control for landing aircraft comprising: -a receiver for receiving location signals; -a flight route manager system for inputting data derived from the locationsignals into the data fields of a request message;-a transmitter for sending a request message when the aircraft is within a control zone, the request including information determined from a location signal; -a receiver for receiving a message from a ground based station containing the coordinates of a common predetermined waypoint to be passed through prior to landing and a unique time at which to pass through the waypoint to implement a landing order; -the flight route manager system further being configured to send the received coordinates and unique time to a flight controller to adjust the aircraft bearing and speed to reach the waypoint at the specified time.
20. An apparatus according to claim 19 wherein the flight controller is an autopilot system.
21. An apparatus according to claim 20 wherein the autopilot system is configured to automatically engage upon receiving the waypoint coordinates and unique time at which to pass through the waypoint.
22. An apparatus according to any of claims 19 to 20 wherein the flight route manager system is arranged to monitor GNSS signals received by the GNSS receiver to determine when the aircraft enters the control zone and, when the aircraft enters the control zone, to set up a data link to communicate with a ground based control system.
23. An apparatus according to claim 19 wherein the flight controller is a pilot and the flight route manager is configured to send the received coordinates and unique time to the cockpit display.
24. An apparatus according to any of claims 19 to 23 wherein the receiver is a GNSS receiver for receiving GNSS signals.
25. A computer programme for carrying out the method of any of claims 1 to 13.* * AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWSCLAIMS1. A method of air traffic control for landing aircraft comprising the steps of: -establishing a data communication link between a first aircraft and a control station when the first aircraft reaches the perimeter of a control zone of a landing airport; -receiving a request message from the first aircraft, the request including information determined from a location signal; -determining a position of the first aircraft in a landing order for a plurality of aircraft by comparing the location information of the first aircraft with location information from the plurality of aircraft and by calculating the arrival time of the first aircraft and each of the plurality of aircraft at a common predetermined waypoint location and assigning the landing order by arrival time; -sending a reply message to the first aircraft containing the coordinates of the waypoint location to be passed through prior to landing, and a first unique time at which to pass through the waypoint to implement the calculated landing order.2. A method according to claim I wherein the information determined from the location signal includes a speed and bearing of the first aircraft.3. A method according to claim 1 or 2 wherein the reply message also contains a speed at which to pass through the waypoint location.4. A method according to any preceding claim wherein the waypoint location is colinear with a runway.5. A method according to any preceding claim wherein the reply message includes instructions to an auto-pilot system indicating the bearing and speed necessary to reach the waypoint at the specified unique time.6. A method according to claim 5 wherein the reply message causes the auto-pilot system of the first aircraft to be automatically activated.7. A method according to any preceding claim wherein, after passing the waypoint, a landing guidance system is automatically activated on the first aircraft.8. A method according to any preceding claim wherein the difference between the first specified unique time and a subsequent specified unique time for a second aircraft, being the aircraft immediately behind the first aircraft in the landing order, is determined so as to allow sufficient time for the first aircraft to land without the second aircraft using a holding pattern or route detour.9. A method according to claim 8 wherein the difference between the first specified unique time and the subsequent specified unique time is dependent upon whether a target runway is also being used for aircraft take-off.10. A method according to any preceding claim wherein the location signal is a Global Navigation Satellite System (GNSS) signal.11. A method according to any preceding claim wherein the coordinates of the waypoint location are based on a GNSS resolution and are suitable for use with a GNSS system.12. A method according to any preceding claim wherein the first unique time to pass the waypoint is specified to an accuracy of the nearest second.13. An apparatus for a ground based station for implementing a method of air traffic control for landing aircraft comprising: -an antenna for receiving request messages from a first aircraft within a control zone including information determined from a location signal; -a memory for storing coordinates of a common predetermined waypoint location to be passed through prior to landing; -a landing order analyzer system for comparing the location information of the first aircraft with location information from a plurality of aircraft and determining a position of the first aircraft in a landing order for the plurality of aircraft by calculating the arrival time of the first aircraft and each of the plurality of aircraft at the waypoint location and specifying a unique time for the first aircraft to pass through the waypoint to implement the landing order; -a transmitter for sending a reply message to specific aircraft containing the coordinates of the waypoint and the unique time to pass through the waypoint.14. An apparatus according to claim 13 wherein the landing order analyzer is coupled to a route monitor that monitors the routes of aircraft in the control zone and the progress of aircraft along the routes, the landing order analyzer using information provided by the route monitor to determine the position of the first aircraft in the landing order for the plurality of aircraft.15. An apparatus according to claim 13 or 14 wherein the landing order analyzer system is configured such that the difference between the unique time specified for the first aircraft to pass through the waypoint and the subsequent specified unique time for a second aircraft immediately behind the first aircraft in the landing order is determined so as to allow sufficient time for the first aircraft to land without the second aircraft using a holding pattern or route detour.16. An apparatus according to claim 13, 14 or 15 wherein the apparatus further comprises a departing order analyzer system that uses information provided and updated by ground controllers to determine anticipated take-off times of aircraft and provides this information to the landing order analyzer system; the landing order analyzer system being further configured to determine the time specified for the first plane to pass through the waypoint based on the information received from the departing order analyzer.17. An apparatus according to claim 16 further comprising a taxi monitor system, for receiving and storing details of aircraft taxiing on the runway or in the vicinity thereof, the departing order analyzer system being coupled to the landing order analyzer system to provide information thereto.18. An apparatus for an aircraft arranged to implement a method according to any of claims 1 to 12 comprising: -a receiver for receiving location signals; -a flight route manager system for inputting data derived from the locationsignals into the data fields of a request message;-a transmitter for sending a request message when the aircraft is within a control zone, the request including information determined from a location signal; -a receiver for receiving a message from a ground based station containing the coordinates of a common predetermined waypoint to be passed through prior to landing and a unique time at which to pass through the waypoint to implement a landing order; -the flight route manager system further being configured to send the received coordinates and unique time to a flight controller to adjust the aircraft bearing and speed to reach the waypoint at the specified time.19. An apparatus according to claim 18 wherein the flight controller is an autopilot system.20. An apparatus according to claim 18 wherein the autopilot system is configured to automatically engage upon receiving the waypoint coordinates and unique time at which to pass through the waypoint.21. An apparatus according to any of claims l8to 19 wherein the flight route manager system is arranged to monitor GNSS signals received by the GNSS receiver to determine when the aircraft enters the control zone and, when the aircraft enters the control zone, to set up a data link to communicate with a ground based control system.22. An apparatus according to claim 18 wherein the flight controller is a pilot and the flight route manager is configured to send the received coordinates and unique time to the cockpit display.23. An apparatus according to any of claims 18 to 22 wherein the receiver is a GNSS receiver for receiving GNSS signals.24. A computer programme for carrying out the method of any of claims 1 to 12.