EP3091525A1

EP3091525A1 - Method for an aircraft for handling potential collisions in air traffic

Info

Publication number: EP3091525A1
Application number: EP15001337.3A
Authority: EP
Inventors: Jörg Meyer; Winfried Lohmiller; Joy Jonatan Bousquet; Peter Feil; Dietmar Klarer
Original assignee: Airbus Defence and Space GmbH
Current assignee: Airbus Defence and Space GmbH
Priority date: 2015-05-06
Filing date: 2015-05-06
Publication date: 2016-11-09

Abstract

The invention relates to a method for an aircraft for handling potential collisions in air traffic, comprising the following steps:
a) providing first data of a cooperative first sensor of a cooperative collision avoidance systems CCAS configured to detect a position of one or more cooperative intruders, wherein the CCAS is configured to provide a vertical or horizontal resolution advisory to avoid a collision with these intruders;
b) providing second data of a non-cooperative second sensor configured to detect the position of one or more intruders irrespective of whether these are cooperative or non-cooperative intruders; and
c) based on first and second data, generating a collision avoid maneuver according to the following principles:
- if second data of the non-cooperative second sensor indicates one or more intruders and a vertical or horizontal resolution advisory is provided by CCAS, an avoid maneuver under the constraints of the vertical resolution or horizontal advisory will be performed in order to avoid collision with these intruders;
- if second data of the non-cooperative second sensor indicates one or more intruders and no vertical or horizontal resolution advisory is provided by CCAS an avoid maneuver will be performed in order to avoid collision with these intruders; and
- if a vertical or horizontal resolution advisory is provided by CCAS and second data of the non-cooperative second sensor indicates no intruders the vertical or horizontal resolution advisory will be followed.

A device for an aircraft for handling potential collisions in air traffic is another aspect of the invention.

Description

FIELD OF THE INVENTION

The invention relates to methods for an aircraft for handling potential collisions in air traffic, devices for an aircraft for handling potential collisions in air traffic and an aircraft comprising such device.

BACKGROUND OF THE INVENTION

EP 1 798 572 A discloses a traffic alert and collision avoidance system (TCAS) system on a host aircraft that includes a processor, a transmitter, and a receiver. The transmitter generates an interrogation signal based upon surveillance alerts, such as approaching aircraft and threat potentials, produced by surveillance radar. The surveillance radar transmits TCAS transmitter interrogation signals and receives replies at a receiving device. A target aircraft includes a surveillance system that receives the interrogation signal at a transmitter receiving device and, when interrogated, generates a standard transponder reply signal via a transmitter.
The second generation of the TCAS system (the so-called TCAS II system), which is used in the majority of commercial aviation aircraft offers the pilot direct, vocalized instructions to avoid danger, known as a resolution advisory. TCAS II systems coordinate their resolution advisories before issuing commands to the pilots of the aircrafts involved. Such resolution advisories consist either of the command to keep level or of vertical avoid maneuvers, so that e.g. if one aircraft is instructed to descend, the other will typically be told to climb - maximizing the separation between the two aircraft.
In the following description, the term "cooperative collision avoid system" (hereinafter abbreviated as CCAS for easy reference though this is not a generally recognized term in the relevant technical field) designates any collision avoid system, which is equipped with a cooperative sensor suitable to detect a position of a cooperative intruder and to provide vertical resolution advisories to avoid a collision with the cooperative intruder. This definition includes in particular the TCAS II system as the most widespread example of such CCAS.
Cooperative sensors are sensors that acquire data only through cooperation with dedicated other sensors. They are usually transponder-based (TCAS, TCAS II, in particular with a Mode S or a Mode C transponder) but may alternatively use other emissions and squitter messages like ADS-B.
Cooperative intruder means an intruder able to cooperate with the cooperative sensor of the own aircraft. They are equipped e.g. with a TCAS (TCAS II or earlier generation), in particular with a Mode S or a Mode C transponder, ADS-B, or alternatively using other emissions and squitter messages like ADS-B.
On the other hand, non-cooperative intruder means an intruder that does not cooperate with a cooperative sensor of the own aircraft (e.g. having no - or faulty, or only inactivated - transponder, TCAS, ADS-B, etc).
The term "intruder" may be understood as unmanned or manned aircraft, drone, object or the like.
Non-cooperative sensors are autonomous in terms of data acquisition and for this purpose do not rely on a cooperation with dedicated other sensors or services. Non-cooperative sensors may be active or passive sensors, e.g. active or passive radio detection and ranging (RADAR) sensors, weather radar sensors, electro-optical sensors, laser range finder, laser detection and ranging (LADAR) sensors, acoustic sensors or infrared sensors.
The known CCAS systems can, however, be further improved in view of avoiding collisions with both cooperative as well as non-cooperative intruders with high reliability.

SUMMARY OF THE INVENTION

Hence, there may be a need to provide an improved method for an aircraft for handling potential collisions in air traffic, which is in particular improved in view of avoiding collisions with cooperative as well as non-cooperative intruders.
The problem of the present invention is solved by the subject-matters of the independent claims. Further advantageous embodiments of the invention are included in the dependent claims. It should be noted that the aspects of the invention described in the following apply both to the methods for an aircraft for handling potential collisions in air traffic and to devices for an aircraft for handling potential collisions in air traffic.
According to the present invention a method for an aircraft for handling potential collisions in air traffic is presented. The method comprises the following steps, not necessarily in this order:

a) providing first data of a cooperative first sensor of a cooperative collision avoidance systems CCAS configured to detect a position of one or more cooperative intruders, wherein the CCAS is configured to provide a vertical or horizontal resolution advisory to avoid a collision with these intruders;
b) providing second data of a non-cooperative second sensor configured to detect the position of one or more intruders irrespective of whether these are cooperative or non-cooperative intruders; and
c) based on first and second data, generating a collision avoid maneuver according to the following principles:
- if second data of the non-cooperative second sensor indicates one or more intruders and a vertical or horizontal resolution advisory is provided by CCAS, an avoid maneuver under the constraints of the vertical or horizontal resolution advisory will be performed in order to avoid collision with these intruders;
- if second data of the non-cooperative second sensor indicates one or more intruders and no vertical or horizontal resolution advisory is provided by CCAS an avoid maneuver will be performed in order to avoid collision with these intruders; and
- if a vertical or horizontal resolution advisory is provided by CCAS and second data of the non-cooperative second sensor indicates no intruders the vertical or horizontal resolution advisory will be followed.

As a result, an improved method for an aircraft for handling potential collisions in air traffic is provided, which is in particular improved in view of avoiding collisions with a non-cooperative intruder. This is achieved as the second data of the second sensor is acquired independently of the existence of any activated cooperative sensor, squitter messages or service on board of the intruder. In other words, the second sensor is able to detect intruders that are not equipped with a transponder, TCAS, ADS-B etc. Further, the generated avoid maneuver is very flexible with respect to the direction of the avoid maneuvers, however any provided resolution advisory of a CCAS is considered in generating the avoidance maneuvers.
Further, the method for handling potential collisions is also suitable for avoiding collisions with e.g. an obstacle on ground (including take-off, landing, taxi) or during formation flight.
In the following, the above is explained in more detail:

The cooperative first sensor of step a) is part of the CCAS. This sensor can be any kind of transponder based cooperative sensor and further any kind of baro-altimeter based cooperative sensor including sensors which are based on ADS-B.
The CCAS may be preferably a transponder based TCAS II system (hereinafter referred to as "TCAS") as explained above. According to a further embodiment the CCAS may be a ADS-B based system, e.g. an ACAS, an ACAS-X or an ACAX-Xu based system.

Exemplarily, TCAS monitors the airspace around an aircraft for other aircrafts equipped with cooperative sensors, e.g. active transponders and warns the pilot of the presence of other transponder-equipped aircrafts which may present a threat of mid-air collision. TCAS may be based on secondary surveillance radar transponder signals and may operate independently of ground-based equipment to provide advice to the pilot on potential conflicting aircrafts. TCAS may involve communication between all aircrafts equipped with appropriate transponders, provided the transponders are enabled and set up properly. Each TCAS-equipped aircraft may interrogate all other aircrafts in a determined range about their position and all other aircrafts may reply to other interrogations. This interrogation-and-response cycle may occur several times per second. TCAS builds a three dimensional map of aircrafts in the airspace, comprising e.g. their range from interrogation and response round trip time, altitude as reported by the interrogated aircraft, and bearing by a directional antenna from the response. By extrapolating current range and altitude differences to anticipated future values, TCAS may determine if a potential collision threat exists. Then, after identifying potential collisions, a vertical avoidance maneuver restricted to changes in altitude and modification of climb/sink rates between the two (or more) conflicting aircrafts may be automatically negotiated.
The CCAS within the meaning of the invention could also be a so-called ACAS which means Aircraft Collision Avoidance System and is a type of ground collision avoidance technology based on ADS-B messages.
The non-cooperative (autonomous) second sensor of step b) is able to detect cooperative as well as non-cooperative intruders. In an example, the second sensor is an active sensor, a passive sensor, an active or passive radio detection and ranging (RADAR) sensor, a weather radar sensor, an electro-optical sensor, a laser range finder, a laser detection and ranging (LADAR) sensor, an acoustic sensor, an ultra-sound sensor or an infrared sensor. In an example, the second data are configured to be used to detect an incorrect position of the obstacle in the first data and/or to detect an incorrect resolution advisory based on the first data.
Exemplarily, the non-cooperative second sensor is a forward looking Sense & Avoid radar sensor, which observes a forward flight sector (e.g. ±110° Azimuth, ±15° Elevation) and provides radar tracks of detected objects. The Sense & Avoid radar may detect aircrafts as well as bigger birds/swarms and also objects on the ground. The Sense & Avoid radar can also provide intruder tracks in bad weather conditions, where visibility would be insufficient for a human pilot.
In the following examples of the functioning of the method according to the invention based on typical intruder situations will be explained. These examples include both single and multi-intruder scenarios involving cooperative and/or non-cooperative intruders.

1. CCAS detects a (cooperative) intruder and generates a resolution advisory. The non-cooperative sensor (preferably a Sense & Avoid radar) detects an intruder as well and the track information of the two sensors are consistent with each other. In this case a avoid maneuver under the constraint of the resolution advisory will be performed.
2. CCAS detects an (cooperative) intruder and generates a resolution advisory. The non-cooperative sensor detects an intruder as well. Track information of the two sensors is inconsistent with each other. In this case the intruders detected by the two sensors will be interpreted as two different intruders. In this case an avoid maneuver under the constraint of the resolution advisory will be performed. An avoid maneuver with respect to the intruder detected by the radar and consistent with the data of the cooperative sensor is performed. Therefore, the resolution advisory of the CCAS (vertical or horizontal avoid) will be performed by all means in order to avoid the cooperative intruder.
3. CCAS detects an (cooperative) intruder and issues a resolution advisory. The non-cooperative sensor does not detect an intruder at all. In this case the resolution advisory of the CCAS dealing with the cooperative intruder is performed.
4. Non-cooperative sensor and cooperative sensor consistently detect an intruder. CCAS does not issue a resolution advisory because CCAS assumes that there is no collision risk with respect to this intruder. As a consequence, no avoid maneuver will be performed (and of course there is no resolution advisory to be performed).
5. Non-cooperative sensor detects an intruder. CCAS does not issue a resolution advisory. Non-cooperative and cooperative sensor data are inconsistent. In this case a avoid maneuver with respect to the intruder detected by the radar is performed.
6. CCAS does not issue a resolution advisory. Non-cooperative sensor does not detect an intruder. No avoid maneuver will be performed.
7. CCAS issues a resolution advisory relating to a cooperative intruder detected by the cooperative sensor. Track data of the cooperative sensor relating to this intruder is confirmed by the sensor data of the non-cooperative sensor. In addition, non-cooperative sensor data indicates the presence of a second intruder not detected by the cooperative sensor (most likely, this second intruder is a non-cooperative intruder). As a consequence, the own aircraft will perform the avoid maneuver with regard to the second intruder under the constraint of the resolution advisory of the CCAS (i.e. a vertical or horizontal avoid maneuver taking into account only the cooperative intruder).
8. Non-cooperative sensor detects two intruders and at the same time cooperative sensor detects only one intruder (which is a cooperative intruder). CCAS does not issue a resolution advisory (i.e. CCAS assumes that there is no collision risk with respect to cooperative intruder). Sensor data of cooperative and non-cooperative sensors with respect to one of the two intruders (the cooperative intruder) are consistent. Then the own aircraft will be commanded to perform an avoid maneuver taking into account the intruder detected by the non-cooperative sensor.
9. Non-cooperative sensor detects two or more intruders whereas cooperative sensor does not detect any of these intruders (most likely the detected intruders are non-cooperative intruders). Based on the various intruder tracks an avoid maneuver will be generated that avoids these two intruders.
10. Non-cooperative sensor and cooperative sensor consistently detect two or more (cooperative) intruders. In this case an avoid maneuver will be performed under the constraints of the vertical resolution advisory from CCAS that will be applied in order to avoid all detected cooperative intruders.

The advantages of the approach according to the invention by applying direction flexible avoid maneuvers with respect to non-cooperative intruders (i.e. intruders not dealt with by the CCAS) are the following:

In controlled airspace air traffic control separates aircraft by assigning either small differences in altitude or large horizontal distances. Aircraft flying from radio beacon to radio beacon in opposite direction typically fly on the same horizontal line and neighbouring flight levels, so that pure vertical avoid manoeuvers under certain circumstances may systematically lead to higher collision risk as compared to horizontal maneuvers, if not performed under the constraints of the resolution advisory.
In mixed scenarios (cooperative intruder(s) handled by CCAS plus non-cooperative intruder(s) not handled by CCAS) an avoid manoeuvre related to an intruder not handled by CCAS assures minimal interference on the handling of (cooperative) intruders by CCAS, if the avoid maneuver is performed under the constraints of any resolution advisory.

The method according to the invention can be used in both piloted and unmanned aircraft. One example for an unmanned aircraft is a so-called RPA (remotely piloted aircraft) where a human controller in a ground station that is connected via data-link controls the aircraft.
For a remotely piloted aircraft and the case where the data-link connection is not available: the human controller can (during the time when the data-link connection is still available) select whether he enables or disables automatic maneuvres during loss of link phases. First and second data from the cooperative and non-cooperative sensors as well as the CCAS data are brought to the attention of a human controller (the pilot of a manned aircraft or the human controller in the ground station of a remotely controlled aircraft) who might manually override the execution of the generated collision avoid maneuver. Specifically, the human controller may stop or inhibit an execution of the resolution advisory provided by the CCAS or the avoid maneuver. As a result, the human operator always has the final authority over the execution of an avoid command.
The warning function may further bring the vertical or horizontal resolution advisory from the cooperative collision avoidance system and the avoid maneuver to the attention of a human controller who might manually override the execution of the fused avoid maneuvers in order to follow the vertical or horizontal resolution advisory or the avoid maneuvers.
In order to increase the situational awareness of the human controller, data acquired by at least another sensor, for example a video camera, or co-operative sensors like an ADS-B system, a FLARM system (an electronic device to selectively alert pilots to potential collisions between aircraft that is optimized for the specific needs of small aircraft such as gliders and/or else) may be provided. In addition this additional information can be fused with the first and second data and thus can be taken into account for the automatic generation of the avoid maneuver.
In order to increase situational awareness basic support functions are provided to assist the human controller in monitoring CCAS and the sensor data of cooperative and non-cooperative sensors:

Display of cooperative data (e.g TCAS, transponder, ADS-B) data on a display.
Display of data from sensors detecting non-cooperative intruders on a display
Overlay of such two data on the same display.

Additional support functions may be available onboard or in the ground station to assist the pilot in monitoring the automatic avoid function and to confirm or dismiss the suggested measures for conflict resolution:

Display of fused intruder tracks (based on sensor data of first and second sensors),
Display of automatic avoid commands.

Preferably, further consistency check support functions may be provided to the pilot:

Software function, checking consistency of CCAS data and data from sensor(s) detecting non-cooperative intruders,
Display of data from sensor(s) detecting non-cooperative intruders with symbols (colors) indicating degree of (in)consistency with CCAS data,
Optional aural alert in case of inconsistency.

However, any resolution advisory or avoid maneuver may be performed automatically, in case of unmanned aircraft or in case a control channel to the aircraft is temporarily not available.
According to the present invention, also a device for an aircraft for handling potential collisions in air traffic is presented. The device comprises:

a cooperative collision avoidance systems CCAS configured to provide a vertical or horizontal resolution advisory to avoid a collision with cooperative intruders, wherein the CCAS is provided with a cooperative first sensor configured to detect the position of cooperative intruders;
a non-cooperative second sensor configured to detect the position of intruders irrespective of whether these are cooperative or non-cooperative intruders;
an avoid unit for generating avoid maneuvers based on intruder tracks of the non-cooperative second sensor and/or under the constraint of the vertical or horizontal resolution advisory provided by the cooperative first sensor; and
an auto pilot or flight control computer for executing the fused avoid maneuvers provided by the avoid-fusion unit.

According to a preferred embodiment the device may further comprise additional sensors. The additional sensors may be FLARM or ADS-B based sensors. According to a further embodiment the device may comprise means for feeding the data acquired by these sensors into the avoid unit.
According to a preferred embodiment the device may further comprise a warning function in order to alert the human controller in case of any inconsistencies between the sensor data of cooperative and non-cooperative sensors.
According to a preferred embodiment the warning function further may bring the vertical or horizontal resolution advisory from the cooperative collision avoidance system and the avoid maneuver generated by the avoid unit to the attention of a human controller who might manually override the execution of the fused avoid maneuvers in order to follow the vertical or horizontal resolution advisory or the avoid maneuvers
These and other aspects of the present invention will become apparent from and be elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will be described in the following with reference to the accompanying drawings:

Fig 1: shows a schematic drawing of an example of an aircraft comprising a device for handling potential collisions in air traffic.
Fig. 2: shows schematically and exemplarily an embodiment of a device for handling potential collisions.
Fig. 3: shows exemplarily a more concrete embodiment of a device for handling potential collisions.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 shows schematically and exemplarily an embodiment of an aircraft 1 comprising a device 2 for handling potential collisions in air traffic. The device 2 may comprise a aforementioned avoid unit.
In this example the aircraft 1 is a piloted aircraft. However the method according to the invention can also be applied for unmanned aircraft that are connected via a data link to a ground station.
The device 2 for handling potential collisions comprises a cooperative collision avoidance systems CCAS (shown in Fig. 2) with a, e.g. transponder-based, cooperative first sensor and a non-cooperative second sensor, the latter being configured to detect the position both cooperative and non-cooperative obstacles. Both sensors will be explained in further detail with reference to Fig. 2.
The aircraft 1 comprises a camera, here a forward looking camera 3, which observes a forward flight sector and provides a video stream to a pilot (or to a RPA operator in the ground control station in case of an unmanned aircraft). The aircraft 1 further comprises an output unit 4 to output one of the options provided by the device for handling potential collisions. The output unit 4 is here a display unit configured to overlay the first and second data. The aircraft 1 further comprises a drive unit 5, for example a flight control computer or an auto-pilot to execute one of the options provided by the device for handling potential collisions.
Figure 2 shows schematically and exemplarily an embodiment of the device 10 for handling potential collisions. The device 2 for handling potential collisions comprises a CCAS 20, e.g. a TCAS II. The CCAS 20 is provided with a cooperative first sensor 21 to detect a position of a cooperative obstacle (e.g. having a transponder, ADS-B or TCAS on board). The CCAS 20 provides a resolution advisory to avoid a collision with the obstacle.
The first sensor may be a transponder based sensor or be based on ADS-B.
The CCAS 20 may comprise a computer unit, antennas and a cockpit presentation (not shown). The computer unit may perform airspace surveillance, intruder tracking, its own aircraft altitude tracking, threat detection, resolution advisory maneuver determination and selection, generation of advisories and/or the like. The computer unit may use pressure altitude, radar altitude and discrete aircraft status inputs from its own aircraft to control collision avoidance logic parameters that determine a protection volume around the aircraft 1. The antennas may comprise a directional antenna mounted on top of the aircraft 1 and either an omnidirectional or another directional antenna mounted on the bottom of the aircraft 1. The cockpit presentation may be an interface with the pilot provided by one or more traffic and resolution advisory displays.
The device 2 for handling potential collisions further comprises a non-cooperative second sensor 22 configured to detect the position of cooperative as well as non-cooperative obstacles.
The second sensor 22 may be an active sensor, a passive sensor, an active or passive radio detection and ranging (RADAR) sensor, a weather radar sensor, an electro-optical sensor, a laser range finder, a laser detection and ranging (LADAR) sensor, an acoustic sensor, an infrared sensor and/or the like. In other words, the first sensor 21 is transponder or ADS-B based, the second sensor 22 is not.
The device 2 for handling potential collisions may further comprise at least one other sensor 23, as e.g. a video camera, a pilot's monitoring, an ADS-B based system, a FLARM based system and/or else.
The device further comprises a suggestion unit 24 configured to provide options for handling potential collisions in air traffic. The suggestion unit is connected with the CCAS 20, the first, second and (optionally) other sensors.
Figure 3 shows a detailed example for a device for handling potential collisions, in this example on board of a RPA which is controlled by a pilot in a ground station. It comprises a CCAS, in this embodiment a so-called TCAS 11 system or an ACAS-X or an ACAS-Xubased CCAS provides its resolution advisory to an auto pilot or flight control computer of the aircraft. As part of the CCAS a transponder-based or ADS-B based first sensor provides its intruder tracks to an avoid-fusion unit. The second sensor of this embodiment is a Sense&Avoid radar sensor. The sensor data of the second non-cooperative sensor are provided to a avoid unit. Optionally, sensor data of additional sensors like ADS-B or FLARM are provided to the avoid unit. In the avoid unit a avoid maneuver is generated based on the sensor data of the non-cooperative intruders and/or the vertical resolution advisory based on co-operative intruders. Based on the generated avoid maneuver the avoid unit generates automatic avoid commands (in order to perform avoid maneuvers) that are routed to the auto pilot or flight control computer. In a so-called D&A safety monitor a consistency check between CCAS sensor data and radar data of the second sensor can be automatically performed. This is of particular importance if the link to the ground station is not available. The D&A safety monitor may inhibit the resolution advisory provided by CCAS if sensor data are inconsistent.
The different options provided by the CCAS, the avoid unit and the D&S safety monitor to the auto pilot/flight control computer may only be executed after they had been made aware to and confirmed by the human controller of the RPA in the ground station, or when the data link to the ground station of RPA is lost. For this purpose various support functions in order to monitor CCAS and the automatic avoid function are provided for the human controller in the ground station. In the example of Fig. 3 the situational awareness of the human controller is increased by the following support functions:

radar situation display providing the radar intruder tracks of the Sense & Avoid radar sensor;
TCAS-II situation display showing TCAS data (TCAS sensor data as well as any resolution advisory);
fused situation display showing fused intruder tracks as well as the suggested automatic avoid commands,
radar and TCAS-II situation display showing radar intruder tracks indicating (e.g. by different colors) degree of (in)consistency with CCAS sensor data. The information shown is established by a software function checking consistency of CCAS sensor data and data from the Sense&Avoid radar.

Assisted by such support functions (and optionally other sensors like a video stream from a forward looking camera) the human controller is able to dismiss any suggested resolution advisory or avoid maneuver by inhibiting a resolution advisory of the CCAS or by inhibiting an automatic avoid command of the avoid unit and in addition may provide any manual avoid commands.
In the example shown the aircraft is a remotely piloted aircraft. However, the method according to the invention can also be applied to manned aircraft where the support functions explained above are provided directly on board of the aircraft.
However, any resolution advisory or avoid maneuver may be performed automatically, in case of unmanned aircraft or in case a control channel to an unmanned aircraft is temporarily not available.
It has to be noted that embodiments of the invention are described with reference to different subject matters. In particular, some embodiments are described with reference to method type claims whereas other embodiments are described with reference to the device type claims. However, a person skilled in the art will gather from the above and the following description that, unless otherwise notified, in addition to any combination of features belonging to one type of subject matter also any combination between features relating to different subject matters is considered to be disclosed with this application. However, all features can be combined providing synergetic effects that are more than the simple summation of the features.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing a claimed invention, from a study of the drawings, the disclosure, and the dependent claims.
In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfil the functions of several items re-cited in the claims. The mere fact that certain measures are re-cited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

A method for an aircraft for handling potential collisions in air traffic, comprising the following steps:
d) providing first data of a cooperative first sensor of a cooperative collision avoidance systems CCAS configured to detect a position of one or more cooperative intruders, wherein the CCAS is configured to provide a vertical or horizontal resolution advisory to avoid a collision with these intruders;

e) providing second data of a non-cooperative second sensor configured to detect the position of one or more intruders irrespective of whether these are cooperative or non-cooperative intruders; and

f) based on first and second data, generating a collision avoid maneuver according to the following principles:
- if second data of the non-cooperative second sensor indicates one or more intruders and a vertical or horizontal resolution advisory is provided by CCAS, an avoid maneuver under the constraints of the vertical or horizontal resolution advisory will be performed in order to avoid collision with these intruders;

- if second data of the non-cooperative second sensor indicates one or more intruders and no vertical or horizontal resolution advisory is provided by CCAS an avoid maneuver will be performed in order to avoid collision with these intruders; and

- if a vertical or horizontal resolution advisory is provided by CCAS and second data of the non-cooperative second sensor indicates no intruders the vertical or horizontal resolution advisory will be followed.
Method according to claim 1, wherein the non-cooperative second sensor is an active sensor, a passive sensor, an active or passive radio detection and ranging (RADAR) sensor, a weather radar sensor, an electro-optical sensor, a laser range finder, a laser detection and ranging (LADAR) sensor, an acoustic sensor, an ultra-sound sensor or an infrared sensor.
Method according to one of the preceding claims, wherein the cooperative first sensor is based on a transponder or on ADS-B.
Method according to one of the preceding claims, wherein the CCAS is a TCAS II,an ACAS,an ACAS-X or an ACAS-Xu.
Method according to one of the preceding claims, wherein the aircraft is either a piloted aircraft or a remotely piloted aircraft.
Method according to one of the preceding claims, wherein data from first and second sensors and CCAS are brought to the attention of a human controller who might manually override the execution of the generated collision avoid maneuver.
Method according to claim 6, wherein data from additional on-board sensors like a forward looking camera, a FLARM system or ADS-B are brought to the attention of the human controller.
A device for an aircraft for handling potential collisions in air traffic, comprising
- a cooperative collision avoidance systems CCAS configured to provide a vertical or horizontal resolution advisory to avoid a collision with cooperative intruders, wherein the CCAS is provided with a cooperative first sensor configured to detect the position of cooperative intruders;

- a non-cooperative second sensor configured to detect the position of intruders irrespective of whether these are cooperative or non-cooperative intruders;

- an avoid unit for generating avoid maneuvers based on intruder tracks of the non-cooperative second sensor and/or under the constraint of the vertical or horizontal resolution advisory provided by the cooperative first sensor; and

- an auto pilot or flight control computer for executing the fused avoid maneuvers provided by the avoid unit.
Device according to claim 8, further comprising additional sensors, like FLARM or ADS-B, and means for feeding the data acquired by these sensors into the data-fusion unit.
Device according to one of the claims 8 or 9, further comprising a warning function in order to alert the human controller in case of any inconsistencies between the sensor data of cooperative and non-cooperative sensors.
Device according to claim 10, wherein the warning function further brings the vertical or horizontal resolution advisory from the cooperative collision avoidance system and the avoid maneuver generated by the avoid unit to the attention of a human controller who might manually override the execution of the generated avoid maneuvers in order to follow the vertical or horizontal resolution advisory or the avoid maneuvers.