Patent Description:
Any mention and/or discussion of prior art throughout the specification should not be considered, in any way, as an admission that this prior art is well known or forms part of common general knowledge in the field.

Commercial aircraft taxiing or being towed by tractors at airports may collide with obstacles, such as other aircraft or structures such as buildings/light towers. This is a long term, major and costly problem for the global airline industry, and it is growing in frequency due to larger aircraft being introduced, and growing numbers of aircraft in service leading to greater congestion at airports, and thus higher potential for collisions. Most collisions are due to a lack of situational awareness on the part of aircrews, or tow tractor crews in the case of aircraft under tow, regarding the proximity of their aircraft to obstacles.

<CIT> describes a system, which combines the present and estimated future positions of the ownship with that of approaching aircraft and/or airfield structure data, and creates an alert to the crew if a threat of a ground incursion is detected. However, the ownship position is determined from an integration with the ownship on-board navigation system, which has been recognized by the inventors to be technically complex and typically requiring a supplemental type certificate (STC) to operate such a system on an aircraft, increasing costs of installation. A stand-alone system is also described in which the ownship position is determined based on a separate GPS module incorporated in the stand-alone system. However, it has been recognized by the inventors that the operation of a separate GPS module in a cockpit environment may provide unreliable data due to shielding/interference from other aircraft systems and structures.

Some airports are equipped with the A-SMGCS (Advanced Surface Movement Guidance & Control System), which is a system "providing routing, guidance and surveillance for the control of aircraft and vehicles in order to maintain the declared surface movement rate under all weather conditions within the aerodrome visibility operational level (AVOL) while maintaining the required level of safety. " (ICAO definition). However, A-SMGCS does not provide collision warning for individual aircraft; traditionally, it is the individual aircrews' responsibility to maintain safe separation of their own aircraft from obstacles.

<CIT> describes a ground obstacle detection system of an aircraft configured to generate and display a graphical user interface (GUI) that includes a graphical representation of a detected obstacle with which the aircraft may collide during a ground operation and an indication of an area of unknown associated with the detected obstacle.

Embodiments of the present invention seek to address at least one of the above problems.

In accordance with a first aspect of the present invention, there is provided an airport ground collision alerting system as defined in claim <NUM>.

In accordance with a second aspect of the present invention, there is provided a method of operating an airport ground collision alerting system, as defined in claim <NUM>.

Embodiments of the present invention aim to provide aircrews and ground crews with situational awareness, by displaying the position of their own aircraft relative to surrounding obstacles, and providing visual/aural warnings when their aircraft is about to hit these obstacles, in order for the crews to take appropriate avoiding action.

In other words, the airport ground collision alerting system (AGCAS) according to example embodiments is a predictive warning system intended to provide visual/aural alerts to aircrews and ground crews when their aircraft is in proximity to obstacles (other aircraft, airport fixed structures) and at risk of hitting them, in order for the crews to take appropriate avoiding action.

<FIG> shows a schematic block diagram of an AGCAS <NUM> according to an example embodiment. The AGCAS <NUM> comprises:
An ADS-B receiver <NUM>. Automatic Dependent Surveillance-Broadcast (ADS-B) is an international surveillance system now standard on all commercial aircraft. The ADS-B system reports an aircraft's identity, type, location, altitude, velocity and heading to air traffic control and other aircraft. It has been recognized by the inventors that ADS-B receiver <NUM>, in addition to providing information on other aircraft in the vicinity of the ownship, can advantageously be used to also determine information about the ownship itself, which is reported by the ownship under the ADS-B standard. Accordingly, no integration with the ownship's on-board navigation system is required, which greatly reduces the technical complexity of using the AGCAS <NUM> on an aircraft and does not require STC to operate. The inventors have also recognized that the ADS-B information has superior reliability compared to determining the ownship information such as location, altitude, velocity from a dedicated GPS module in a cockpit environment, due to shielding/interference from other aircraft systems and structures.

The data received by the ADS-B receiver <NUM> is provided to an aircraft database <NUM> of the AGCAS <NUM>. The aircraft database <NUM> stores/updates the information about the ownship and other aircraft, such as e.g. ID, position, type and heading. The aircraft database <NUM> enables the look up of the aircraft ID code into the aircraft type, dimensions and other aircraft specific information, which will be used by the collision detection algorithm, as will be described in more detail below.

The AGCAS <NUM> optionally also comprises a GPS receiver <NUM> housed into the AGCAS <NUM>. This can provide back-up or redundant determination for the ownship location, for example if there is a failure of the on-board ADS-B transmitter system (not shown) and/or the ADS-B receiver <NUM>.

The AGCAS <NUM> optionally also comprises an inertial measurement unit (IMU) <NUM>, housed into the AGCAS <NUM>. The IMU <NUM> can provide back-up or redundant determination of the orientation of the aircraft and can advantageously also be used for smoothing the output from the GPS receiver <NUM> based on the aircraft movement.

The AGCAS <NUM> also comprises an airport and obstacle database <NUM> for storing digital airport maps, which contain all fixed obstacles in the airport that pose a collision risk to aircraft, e.g. buildings, light towers, jet blast deflector etc. Preferably, the airport and obstacles database <NUM> will contain maps of all major international airports. The maps can be developed from satellite imagery and aerodrome charts, as will be appreciated by a person skilled in the art.

The AGCS <NUM> also comprises a processor/computing unit <NUM> with a software application installed thereon, running a collision detection algorithm. The algorithm continuously compares its own aircraft location against other aircraft locations and airport obstacles and generates warnings when there is a potential collision. In <FIG>, two main functions performed by the algorithm have been indicated by boxes <NUM> and <NUM>, namely ownship location and safety bubble calculation (box <NUM>), and collision prediction (box <NUM>).

The AGCAS <NUM> may comprise a built-in battery (not shown) and/or may be configured for powering from power outlets that may be available on-board in the cockpit.

An electronic display device <NUM> is coupled to the AGCAS <NUM>, which may be a tablet or a laptop, to display the relevant airport map and system advisories. The electronic display device <NUM> is coupled wirelessly to the AGCAS <NUM> in this embodiment, but may be coupled via wire in different embodiments. It is noted that the electronic display device <NUM> is preferably provided by the user/customer and hence not part of the AGCAS <NUM>, as cockpit tablet and/or laptops are now widely used by most airlines. However, the electronic display device <NUM> may be provided as part of the AGCAS <NUM> in different embodiments, either physically integrated with, or separate from, the AGCAS <NUM> housing.

The AGCAS <NUM> according to an example embodiments provides a system and/or method for avoiding airport ground collisions.

The AGCAS <NUM> can be installed in the aircraft cockpit. The ADS-B receiver <NUM> collects various information regarding the ownship as well as other aircraft, the information including, for example, aircraft ID code, callsign, location, velocity, heading, altitude etc..

The aircraft database <NUM> enables the look up of the obtained aircraft ID code(s) into the aircraft type, dimensions and other aircraft specific information for the ownship and other aircraft, which will be used by the collision detection algorithm and is provided to the processor/computing unit <NUM> by the aircraft database <NUM>.

The collision detection algorithm running on the processor/computing unit <NUM> continuously compares the ownship location and a calculated safety bubble around the ownship (compare box <NUM>) against other aircraft locations and airport obstacles provided to the processor/computing unit <NUM> by the airport and obstacle database <NUM>, to perform collision prediction (compare box <NUM>). The collision detection algorithm running on the processor/computing unit <NUM> generates warnings, which are sent to the electronic display device <NUM> when there is a potential collision.

The electronic display device <NUM> used by the pilots is loaded with a proprietary software and/or algorithms including a map engine <NUM> for the display of the ownship's current position, indicated by a symbol such as a schematic image of an aircraft, dynamically within the relevant airport map, and for the drawing and displaying of a safety bubble around the ownship's location as a visual aid, according to the size and dimensions of the aircraft. The proprietary software and/or algorithm also includes a graphical user interface (GUI) application <NUM>, configured to enable visual and/or aural warnings to a user via the electronic display device <NUM>. The map information from the airport and obstacles database <NUM> may be provided to the electronic display device <NUM> via an electronic display interface/application programming interface (API) <NUM>. Alternatively or additionally, the electronic display device may be loaded with its own airport and obstacles database <NUM>.

With reference to <FIG> and <FIG>, the safety bubble 200a, 200b is drawn to envelope the aircraft, represented by symbol <NUM>, and may change in colour in order to provide visual warning to the user in case of an impending collision. Preferably, the safety bubble 200a, 200b and/or the symbol <NUM> will move and rotate according to the aircraft orientation. Advantageously, the safety bubble 200a, 200b also grows longitudinally in proportion to the aircraft's direction of travel and velocity on the map 204a, 204b. For example, in a forward movement scenario, the safety bubble 200a, 200b will be elongated in a forward direction away from the cockpit to account for aircrew reaction/aircraft braking time in trying to avoid a potential collision. The amount of the elongation will be proportional to the current speed of the aircraft.

The safety bubble 200a, 220b and symbol <NUM> are overlaid on the digital map 204a, 204b of the airport, with the map 204a, 204b containing information about stationery obstacles such as buildings e.g. <NUM> and the safety bubbles e.g. <NUM> of other aircraft calculated and displayed in the same fashion as for the ownship. Moving aircraft (not shown) in the vicinity of the ownship will be displayed with a corresponding moving safety bubble, which may also grow longitudinally in proportion to the aircraft's direction of travel and velocity on the map 204a, 204b.

The map 204a, 204b of the airport advantageously also contains airport features to give the pilots a better situational awareness, including buildings e.g. <NUM>, runways, taxiways e.g. 210a, 210b, parking bays e.g. 212a, 212b and markings e.g. 214a, 214b on the tarmac.

The electronic display device <NUM> (see <FIG>) will receive collision warnings from the AGCAS <NUM> (see <FIG>), specifically from an electronic display interface/application programming interface (API) <NUM> (see <FIG>) and will visually and audibly alert the pilots if there is potential danger of collision. This can take the form of an aural voice message and/or visual warnings such as change in the safety bubble 200a, 200b display color and/or a flashing visual warning on the electronic display device <NUM> (see <FIG>).

Optionally, the GPS receiver104 (see <FIG>) collects back-up or redundant information about the ownship position, while the IMU <NUM> (see <FIG>) is optionally used to provide the orientation of the aircraft and to smoothen the output from the GPS receiver <NUM> (see <FIG>).

Optional additional functionalities according to example embodiments.

Swept wing aircraft experience a phenomenon known as "wing growth" when they turn. A swept wing is a wing that angles backward (most common, but occasionally forward) from its root at the aircraft's fuselage. Because the main wheels of the aircraft are typically located at or close to the root of the wings at the fuselage, when the aircraft is turning the tip of the wing facing away from the centre of the turn moves on a trajectory that goes beyond the wingspan-based distance from the fuselage prior to turning. For example, as the aircraft turns left, the tip of the right wing will move rightwards relative to its original position during the initial stages of the turn. Accordingly, the safety bubble (compare 200a, 200b in <FIG>) is expanded at the relevant tip area of the swept wing when a turn is detected. Specifically, the wing growth advisory function of an AGCAS according to an example embodiment advantageously provides a warning when it is detected that the aircraft is turning by detecting heading changes based on the ADS-B data (or the GPS data in back-up/redundant mode) and will expand the safety bubble laterally in size to depict the relative wing growth of the outboard wing span, to visualize the longest distance from the apex of the turn. The AGCAS according to such an embodiment will issue a warning when there is an imminent collision with an obstacle by the expanded safety bubble and this will be indicated on the display.

In one embodiment, the software application installed on the processor/computing unit (compare <NUM> in <FIG>) advantageously provides a de-clutter mode to disregard ADS-B signals of aircraft that are not near (as compared to a threshold distance, which may be preinstalled and/or user selectable), and do not pose a collision risk to the ownship. These aircraft will be suppressed from display on the electronic display (compare <NUM> in <FIG>), making it easier for the crew to focus on the more relevant information displayed.

The AGCAS according to example embodiments relies on aircraft transmitting their presence and location via ADS-B in order to be detectable, or fixed airport obstacles to be recorded in the airport map. Once an aircraft has parked and powers down, the ADS-B signal will be lost and the aircraft is no longer detectable.

To address this problem, a non-transmitting aircraft functionality feature can be provided in the AGCAS according to an example embodiment, in the form of a temporary aircraft database. Prior to an aircraft shutting down, its associated AGCAS according to such an example embodiment will record and remember the last position of the aircraft. It is noted that the temporary aircraft database is not resident in the AGCAS located on board the aircraft. Instead, the temporary aircraft database is remotely located, e.g. in a cloud server (compare <NUM> in <FIG>). Whenever any aircraft (whether AGCAS equipped according to example embodiments or not) shuts down, the ADS-B signal is lost, and the system records that loss of signal as the last position of the aircraft, so no user input is needed. As long as there are several AGCAS-equipped aircraft operating at an airport, their processors will record the loss of ADS-B signal, and communicate this update to the server via internet connection. This information is sent to the temporary aircraft database, for example in the form of the cloud server (compare <NUM> in <FIG>), which also collates such reports from other AGCAS associated with other aircraft.

When a user starts up their AGCAS according to such an example embodiment and loads the map for an airport, the AGCAS will connect to the temporary aircraft database, e.g. the cloud server (compare <NUM> in <FIG>), and retrieve the last recorded position of non-transmitting aircraft that are located at the relevant airport, and thus will advantageously be able to indicate the location of a parked aircraft, even though the aircraft is shut down and not transmitting its position.

It is noted that parked aircraft may be relocated from one position to another for various reasons, and the temporary aircraft database preferably keeps track of these movements, in order to remain current and not lose its relevance. This update can for example be achieved in two ways according to example embodiments:.

As the on-board AGCAS according to example embodiments has a priori knowledge of the aircraft type it is being used on, the digital airport map engine (compare <NUM> in <FIG>) can be programmed with logic to display airport information pertinent only to a particular aircraft type in an example embodiment.

For example, aircraft that are classified as ICAO Code F aircraft (wingspan exceeding <NUM>, but less than <NUM>), may encounter some areas in an airport which cannot accommodate their large wingspan. In this case, for an aircraft equipped with an AGCAS according to such an embodiment, the airport map engine (compare <NUM> in <FIG>) will cause the display to indicate an visual sign such as an 'X' on the relevant area of the map display, warning the crew not to enter this area/taxiway. For smaller aircraft, this restriction will not be displayed.

The AGCAS according to an example embodiment can comprise a software for monitoring relevant NOTAMs (Notice to Airmen) information and mines out the relevant information related to airfield conditions and updates them on the map. The software can be installed and run on the processor/computing unit (compare <NUM> in <FIG>). It is noted that the AGCAS according to example embodiments may not itself "receive" the NOTAM, but it "learns" about the NOTAMs by uploading updated maps (compare airport database <NUM> in <FIG>) that have incorporated NOTAM advisories. The update to the map is performed offline with respect to the AGCAS according to such example embodiments, by a server that houses all the airport maps.

Specifically, Airport Authorities publish short-term changes to an airport via means of NOTAMs, or Notice to Airmen. There are several categories of NOTAMs, including one specific to airport surface operations.

As NOTAMs are published in a standard format, the AGCAS according to such embodiments runs a computer algorithm to intelligently mine NOTAMs online, filter out all non-applicable NOTAMs, i.e. identifying only those affecting the relevant airport surface operations, and further identifying which of those NOTAMs affect runway/taxiway/apron operations.

The digital airport map engine (compare <NUM> in <FIG>) preferably enables layered control/display of the digital airport maps. Hence, because the digital maps consists of layers in such example embodiments, it is possible to have a layer to display current airport status information, such as closure of a particular taxiway. For example, when the AGCAS according to such example embodiments loads and displays an airport map, it will also indicate that a particular runway is closed to aircraft traffic, as per the mined NOTAMs.

An AGCAS master display version according to an example embodiment can be provided for an airport's ATC tower for enhanced ground control, displaying all ground aircraft movements. This AGCAS master display version according to such an embodiments works in a similar manner to the AGCAS <NUM> (see <FIG>) used on-board an aircraft or on a towing tractor, in that it will also predict collisions for individual aircraft, even if these aircraft themselves are not equipped with an AGCAS according to example embodiments. The AGCAS master display version according to such an example embodiment can have a fixed display of the airport and showing the entirety of the airport and all ground aircraft traffic.

Advantageously, the AGCAS master display version according to such an example embodiment allows ATC controllers to have additional situational awareness, and enabling them to warn aircrews of impending collisions. Practically, this will likely entail a policy/procedural change for ATC, as it means ground controllers would be assuming responsibility for collision avoidance, when it is traditionally the aircrews' responsibility as previously mentioned.

<FIG> shows a flowchart <NUM> illustrating a method of operating an airport ground collision alerting system according to the invention.

The various functions or processes of the example embodiments disclosed herein may be described as data and/or instructions embodied in various computer-readable media, in terms of their behavioral, register transfer, logic component, transistor, layout geometries, and/or other characteristics. Computer-readable media in which such formatted data and/or instructions may be embodied include, but are not limited to, non-volatile storage media in various forms (e.g., optical, magnetic or semiconductor storage media) and carrier waves that may be used to transfer such formatted data and/or instructions through wireless, optical, or wired signaling media or any combination thereof. Examples of transfers of such formatted data and/or instructions by carrier waves include, but are not limited to, transfers (uploads, downloads, e-mail, etc.) over the internet and/or other computer networks via one or more data transfer protocols (e.g., HTTP, FTP, SMTP, etc.). When received within a computer system via one or more computer-readable media, such data and/or instruction-based expressions of components and/or processes under the system described may be processed by a processing entity (e.g., one or more processors) within the computer system in conjunction with execution of one or more other computer programs.

Aspects of the systems and methods according to example embodiments described herein may be implemented as functionality programmed into any of a variety of circuitry, including programmable logic devices (PLDs), such as field programmable gate arrays (FPGAs), programmable array logic (PAL) devices, electrically programmable logic and memory devices and standard cell-based devices, as well as application specific integrated circuits (ASICs). Some other possibilities for implementing aspects of the system include: microcontrollers with memory (such as electronically erasable programmable read only memory (EEPROM)), embedded microprocessors, firmware, software, etc. Furthermore, aspects of the system may be embodied in microprocessors having software-based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neural) logic, quantum devices, and hybrids of any of the above device types. Of course the underlying device technologies may be provided in a variety of component types, e.g., metal-oxide semiconductor field-effect transistor (MOSFET) technologies like complementary metal-oxide semiconductor (CMOS), bipolar technologies like emitter-coupled logic (ECL), polymer technologies (e.g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, etc..

Claim 1:
An on-board airport ground collision alerting system (<NUM>) for use on-board an aircraft, the airport ground collision alerting system (<NUM>) comprising:
an automatic dependent surveillance-broadcast, ADS-B (<NUM>), receiver;
a first database (<NUM>) coupled to the ADS-B (<NUM>) receiver and configured for look-up of aircraft type data based on aircraft ID data received via the ADS-B (<NUM>) receiver and for storing aircraft position and heading data received via the ADS-B (<NUM>) receiver;
a second database (<NUM>) configured to store digital map data for one or more airports;
a processor unit (<NUM>) coupled to the first and second databases (<NUM>, <NUM>) and configured to:
determine a position and heading of the aircraft on-board of which the airport ground collision alerting system is being used based on the position and heading data of the aircraft stored in the first database (<NUM>) as received from an on-board ADS-B (<NUM>) transmitter of said aircraft via the ADS-B (<NUM>) receiver in an ADS-B transmission, the on-board ADS-B (<NUM>) transmitter being external to the on-board airport ground collision alerting system;
determine respective positions and headings of one or more other aircraft at a current airport based on the position and heading data received from the first database (<NUM>);
determine respective locations of one or more obstacles at the current airport based on the digital map data received from the second database (<NUM>); and
predicting whether a ground collision will occur between the aircraft and one or more of a group consisting of the one or more other aircraft and the one or more obstacles;
the airport ground collision alerting system (<NUM>) further comprising an application programming interface, API (<NUM>), configured to:
couple the airport ground collision alerting system to a display device (<NUM>);
cause the display device (<NUM>) to display a symbol representative of the aircraft overlaid on at least a portion of a digital map of the current airport based on the position and heading of the aircraft determined by the processor unit (<NUM>); and
cause a warning to be generated via the display device (<NUM>) if the ground collision is predicted to occur by the processor unit (<NUM>).