FIELD OF INVENTION
The present invention generally relates to the field of air traffic control (ATC) system. More particularly, the present invention relates to a method for real time object label overlap avoidance for air traffic control system.
BACKGROUND
The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Air Traffic Management System (ATMS) has been conceptualized as one of the most advanced automated air traffic control systems which meet international standards and recommended practices in air traffic management.
The Air Traffic Control (ATC) system is a complex system that monitors, controls and assists all aircraft to safely transit the skies from take-off to landing. The purpose of air- traffic control is to assure safe separation between en-route aircraft and the safe and efficient handling of aircraft operations at airports. The system is based on information integration, which integrates all kinds of fundamental information such as Airport Surveillance Radar (ASR) with Mono-pulse Secondary Surveillance Radar (MSSR), flight plans, voice communication and weather information into a comprehensive information platform.
The Controller Working Position (CWP) is the front-end of the ATC System providing single point interface to the Air Traffic Controllers. These Working Positions facilitate the ATC operations at different locations in the airport, which varies with type of Radar and its usage. CWP is comprised of multiple presentation utilities such as Menu Bar, Title Bar, Textual Information Area, Picture-in-Picture (PIP) Window and the Air Situation Picture (ASP).
The ASP displays synthetic aircraft symbols with information such as Aircraft Data Descriptor (ADD) along with Surveillance areas, Radar control sectors, Weather information, Radar raw video and many more. ADD displays the basic identification

information of the aircraft such as Call-sign, Unique track number, IFF code along with kinematic parameters such as speed, course and height.
[0007] The contents of the ADD can be configured as per operator’s discretion. A
connector line is displayed that connects aircraft symbol to its corresponding ADD. With the movement of aircraft, the ADD position is also updated in order to keep them associated. Each individual ADD can be manually repositioned by the operator as desired for convenience of operation.
[0008] When there is huge traffic in the air or multiple aircrafts are in close
proximity, these ADD may overlap with each other or ADD may overlap with aircraft symbol. This results in hiding of the important data (i.e. other aircraft's information or the aircraft itself or alert information or the movements of other aircraft) on ASP. Along with this, there might occur a situation when the critical data of aircraft such as Short Term Conflict Alert (STCA: prediction and violation of separation between aircraft in standard airspaces), Minimum Safe Altitude Warning (MSAW: prediction and violation of altitude separation between aircraft and terrain) alerts are missed by the controller due to overlaps leading to a catastrophic situation. All these things make it troublesome for the controller to clearly see the ASP for better air route controlling.
[0009] Based on the above, two scenarios that may occur due to overlap of the ADD:
(i) Scenario 1: - ADD is positioned over the aircraft symbol and speed vector of another aircraft. In this scenario, the controller might no longer be immediately aware of changes in the location and heading of the obscured aircraft; (ii) Scenario 2: - Two ADDs are overlapping with each other, making one or both unreadable and when the zoom-in operation is performed the ADD of nearby aircrafts overlap. In current scenario to overcome these problems the controller has to arrange the ADD by repositioning them manually as described above. This increases the load on the controller and moreover, it is a time-consuming process especially when there is high traffic and condition is critical.
[0010] A few techniques have been proposed for the cluttering problem. “Cluster
Based” technique is considered effective compared to the other ones. “Cluster Based” techniques work by dividing the area surrounding the aircraft into clusters. Following solutions makes use of this technique to give their respective algorithms: Solution 1: -Duverger proposed “Mathematical Weighted Function (MWF) de cluttering algorithm”. According to this algorithm, the aircraft's surrounding is divided into grids. Each grid is defined with eight cells and size of each cell is per pixel. Each grid cell is assigned a cost. The cost of each cell is calculated based on following parameters: (i) Overlap; (ii) angle of

leader line; (iii) distance from current position; (iv) time since last movement; and (v) length of leader line. Based on the cost, cells are divided into three categories with three different colour codes. Dark grey being the most overlapped cell, medium grey being average and light grey the most suitable cell to avoid overlaps. The cost for each cell is calculated and the search algorithm is applied to find out the best suitable location for the label. The problem in this algorithm is that a finite search scope is not defined. This makes it less feasible to use in practical situations. Complexity of this algorithm is O(n2) where n is: n = No. of Aircraft/Labels. Solution 2: - Azuma proposed a technique based on “Probabilistic Roadmap (PRM)”. According to this technique, the area around the aircraft is divided into cluster. The labels are moved in random directions inside the cluster. The cost matrix is generated for each state. After moving the labels, the current cost matrix is compared with previous one. The process is repeated until the most feasible clutter free state is achieved.
[0011] The problem with his technique is that it is a very time-consuming process. No
proper criteria are defined for this random movement of labels. Complexity of this algorithm is O(tk2(n2+log(k)+t)); where t, k and n are: n = No. of Aircraft; t = No. of time Steps; and k = No. of States generated per time Step. Unlike Duverger’s algorithm which fails to define the finite search scope, the proposed method defines a proper search scope based on experimental results. Azuma’s approach on the other hand is a time-consuming process which makes it less feasible to use in practical situations. To overcome this, the proposed method defines accurate search criteria to reduce the time consumption and also gives efficient and effective results in real time scenarios.
[0012] There is thus a need of certain technique which provides solution to get rid of
this cluttering situation. This brings the requirement of developing a method to reduce the workload of the controller and to solve the overlapping problem efficiently. Therefore, ‘Method for Real Time Object Label Overlap Avoidance for Air Traffic Control System’ has been designed and developed.
OBJECTS OF THE PRESENT DISCLOSURE
[0013] Some of the objects of the present disclosure, which at least one embodiment
herein satisfies are as listed herein below:
[0014] It is an object of the present invention to develop a method to reduce the
workload of the controller and to solve the overlapping problem efficiently.
[0015] Another object of the present invention is to provide a method to design and
develop Real Time Object Label Overlap Avoidance for Air Traffic Control System.

[0016] Yet another object of the present invention is to provide accurate search
criteria to reduce the time consumption and also gives efficient and effective results in real time scenarios.
SUMMARY
[0017] The present disclosure relates to a method for real time object label overlap
avoidance for air traffic control system which provides a clear overlap free picture of ASP to controller. This method makes use of the angle that ADD makes with aircraft and the radius of ADD from aircraft to find feasible position of ADD in order to avoid overlaps. ATMS System is designed with state-of-art algorithm and design methodologies for providing 24x7 Operations, High-Availability, Fail-Safe system comprising of Data Processing systems, Controller Display systems, Surveillance & Monitoring systems, Simulator system, Recording and Playback systems. The Controller Working Position (CWP) is one of the most critical and important system which provides a single point interface to the ATC operator for controlling and monitoring purpose.
[0018] This summary is provided to introduce simplified concepts of a system for
time bound availability check of an entity, which are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended for use in determining/limiting the scope of the claimed subject matter.
[0019] An aspect of the present disclosure pertains to an air traffic control system.
The system includes a declutter tool and a display unit. The declutter tool is configured to determine whether a display overlap exists for a target aircraft data descriptor (ADD) associated with a target aircraft on the display unit with at least one of a plurality of ADD. The plurality of ADD is associated with aircrafts other than the target ADD. The declutter tool is also configured to position, if the display overlap exists, the target ADD on the display unit away from an overlapping ADD from the plurality of ADD such that the target ADD is in a clutter-free position on the display unit.
[0020] In an aspect, when determining whether the display overlap exists, the
declutter tool is further configured to consider the plurality of ADD in a sequential manner.
[0021] In an aspect, when positioning the target ADD, the declutter tool is further
configured to rotate the target ADD in a clockwise direction so as to achieve the clutter-free position on the display unit.

[0022] In an aspect, the target ADD is rotated about an angle of intersection between
the target ADD and the at least one of the plurality of ADD.
[0023] In an aspect, the plurality of ADD includes one thousand ADDs.
[0024] Another aspect of the present disclosure pertains to a method which includes
determining, at a declutter tool, whether a display overlap exists for a target aircraft data
descriptor (ADD) on a display unit with at least one of a plurality of ADD, the plurality of
ADD being associated with aircrafts other than the target ADD; and positioning, at the
display unit, if the display overlap exists, the target ADD on the display unit away from an
overlapping ADD from the plurality of ADD such that the target ADD is in a clutter-free
position on the display unit.
[0025] In an aspect, when determining whether the display overlap exists, the
declutter tool is further configured to consider the plurality of ADD in a sequential manner.
[0026] In an aspect, when positioning the target ADD, the declutter tool is further
configured to rotate the target ADD in a clockwise direction so as to achieve the clutter-free
position on the display unit.
[0027] In an aspect, the target ADD is rotated about an angle of intersection between
the target ADD and the at least one of the plurality of ADD.
[0028] In an aspect, the plurality of ADD includes one thousand ADDs
[0029] Various objects, features, aspects and advantages of the inventive subject
matter will become more apparent from the following detailed description of preferred
embodiments, along with the accompanying drawing figures in which like numerals represent
like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The accompanying drawings are included to provide a further understanding
of the present disclosure and are incorporated in and constitute a part of this specification.
The drawings illustrate exemplary embodiments of the present disclosure and, together with
the description, serve to explain the principles of the present disclosure.
[0031] In the figures, similar components and/or features may have the same
reference label. Further, various components of the same type may be distinguished by
following the reference label with a second label that distinguishes among the similar
components. If only the first reference label is used in the specification, the description is
applicable to any one of the similar components having the same first reference label
irrespective of the second reference label.

[0032] FIG. 1 represents the scenario 1 as mentioned in section 2 where the
overlapping results in hiding the information of another aircraft, in accordance with an
embodiment of the present disclosure.
[0033] FIG. 2 represents the scenario 2 as mentioned in section 2 where the ADDs
overlap when the ASP is zoomed in, in accordance with an embodiment of the present
disclosure.
[0034] FIG. 3 illustrates Flowchart of the Declutter Tool, in accordance with an
embodiment of the present disclosure.
[0035] FIG. 4 shows the pictorial representation of method, in which the angle
increment of connecting line by a factor of Ѳ is represented, in accordance with an
embodiment of the present disclosure.
[0036] FIG. 5 shows the pictorial representation of method, in which the radius
increments of connecting line by a factor of overlapping width w is represented, in
accordance with an embodiment of the present disclosure.
[0037] FIGs. 6 and 7 represents the ASP with multiple aircrafts and their associated
ADDs, in accordance with an embodiment of the present disclosure.
[0038] FIGs. 8 and 9 represents the results of real time implementation of the method
proposed corresponding to Fig 6 and Fig 7 respectively as an input, in accordance with an
embodiment of the present disclosure.
[0039] FIG. 10 shows information related to calculation of intersection label angle
and intersection width, in accordance with an embodiment of the present disclosure.
[0040] FIG. 11 represents the hardware system which comprises of Declutter Tool,
Display Unit, Communication Port, Processor and an External Device which contains Track
Data Module and Database Module, in accordance with an embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0041] In the following description, numerous specific details are set forth in order to
provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0042] FIG. 1 represents the scenario 1 as mentioned in section 2 where the
overlapping results in hiding the information of another aircraft while FIG. 2 represents the scenario 2 as mentioned in section 2 where the ADDs overlap when the ASP is zoomed in, in

accordance with an embodiment of the present disclosure. These figures can be indicative of
the problem being solved by the present disclosure. As can be appreciated further, a system
and a method associated with the solution for the same has been presented herein.
[0043] Referring now to FIG. 11 which represents a hardware system which can
include a declutter tool, a display unit, a communication port, a processor, and an external
device which contains Track Data Module and Database Module, in accordance with an
embodiment of the present disclosure. While the declutter tool and the display unit can be
indicative of the system disclosed herein, the other mentioned aspects or components can be
part of the system or the method as can be appreciated by those skilled in the art. The present
disclosure and the solution offered herein is particularly directed to an air traffic control
system which can include the aforementioned declutter tool, and the display unit.
[0044] The linkage between the method, the system, and the hardware system can
also be said to be represented by Fig 11 which shows the hardware system. The hardware system can include the declutter tool, Display Unit, Communication Port, Processor and an External Device which contains Track Data Module and Database Module. These systems can communicate with each other via Local Area Network (LAN). The database and Track data are operatively coupled to the Declutter Tool such that the information is available bi-directionally to the Declutter tool and external systems. The track related data for ADD is received from real time track data and the other data such as weather data, surveillance area, controller sector, raw video etc. are received from database. The processed data from Declutter Tool is forwarded to the Display Unit. The corresponding data is hence displayed at Display Unit.
[0045] Development of framework/module: Steps used in the method for these
requirements are: (I) For each ADD, check whether there is an overlap with any other ADDs: a) If there is no overlap, then proceed to next ADD in sequence; and b) Otherwise, rotate the ADD by an angle of intersection of overlap area of ADD in the clockwise direction. (II) With each rotation check the overlap again. Repeat this until the non-overlapping position for the ADD is found. (III) When the angle reaches 3600 and there still is an overlap area: (a) Reset the value of the ADD angle to 00; (b) Increase the radius by the width of intersection of overlap area of ADD (i.e. increase the length of line connecting ADD and aircraft). (IV) With the increased radius rotate the ADD and check for overlap area again; (V) Repeat this process for around 100 iterations to get the clutter free display having approximate 1000 aircraft and corresponding 1000 ADD associated with them.

[0046] In an embodiment, the declutter tool as shown in FIG. 11 is configured to
perform the above-mentioned steps. The system can include a declutter tool and a display
unit at a minimum but can include other aspects and components in other embodiments.
[0047] In an embodiment, the declutter tool is directed to a target ADD (i.e. an ADD
at issue which can be concerned with one particular aircraft for example, or that which a user wishes to interact with at any given time) and performs the above-mentioned steps with respect to that target ADD. The display unit can be any unit known in the art including, but not limited to, a simple display system associated with an aircraft system (with regards to the target ADD for example, and without deviating from the spirit and scope of the current disclosure), an auditory medium, or a tactile medium, or other medium that can serve a similar purpose.
[0048] In an embodiment, the overlap mentioned is directed to a display overlap
associated with the display unit. The “display” in the display overlap can refer to the ADD mentioned above with respect to an aircraft or other like item, and therefore can include the ADD of the aircraft i.e. the target ADD. This may be represented by FIGs. 6 and 7 represents the ASP with multiple aircrafts and their associated ADDs, in addition to FIGs. 8 and 9 represents the results of real time implementation of the method proposed corresponding to Fig 6 and Fig 7 respectively as an input.
[0049] In an embodiment, the present disclosure pertains to an air traffic control
system. The system can include a declutter tool and a display unit, as mentioned herein. The declutter tool can be configured, by appropriate means known in the art, to determine whether a display overlap exists for a target aircraft data descriptor (ADD) associated with a target aircraft on the display unit with at least one of a plurality of ADD. The display overlap can refer to the overlap of an ADD of another aircraft with the target ADD and thus can refer to the overlap of an area of the target ADD with respect to the ADD of the aforementioned other aircraft. The display overlap can exist on a display unit. As mentioned, the plurality of ADD is associated with aircrafts other than the target ADD.
[0050] In an embodiment, the declutter tool is also configured to position, if the
display overlap exists, the target ADD on the display unit away from an overlapping ADD from the plurality of ADD such that the target ADD is in a clutter-free position on the display unit. The mentioned clutter-free position can refer to the target ADD being clearly visible on the display unit. In other words, the target ADD can exist on the display unit with the plurality of the ADD being present towards or at the sides. In some embodiments, the plurality of ADD can be proximate but not overlapping with respect to the target ADD.

[0051] In an embodiment, when determining whether the display overlap exists, the
declutter tool is further configured to consider the plurality of ADD in a sequential manner.
The sequential manner can include the consideration of the declutter tool with respect to the
plurality of ADD one after the other, as can be appreciated by those skilled in the art. In some
embodiments, this aspect can be performed simultaneously. In other words, the declutter tool
can consider two or more of the plurality of the ADD at any given time.
[0052] In an embodiment, when positioning the target ADD, the declutter tool is
further configured to rotate the target ADD in a clockwise direction so as to achieve the
clutter-free position on the display unit. In some embodiments, the declutter tool can perform
this aspect in other directions including anti-clockwise direction.
[0053] In an embodiment, the target ADD is rotated about an angle of intersection
between the target ADD and the at least one of the plurality of ADD. This can occur between
two or more of the plurality of ADD when the declutter tool can be configured to compute an
angle of intersection and rotate precisely, the target ADD on the display unit so as to achieve
the clutter-free position.
[0054] In an aspect, the plurality of ADD can include one thousand ADDs. In
particular, the number of ADDs can depend upon the number of air traffic that may be
present at a respective airport, or an aerodrome, or the like.
[0055] Another embodiment of the present disclosure pertains to a method as shown
in FIG. 3 which illustrates a flowchart of the declutter tool which can be a solution to the
instant problem. The method can include determining, at the declutter tool, whether the
display overlap (see also FIG. 11 for the system architecture) exists for a target aircraft data
descriptor (ADD) on the display unit with at least one of a plurality of ADD, the plurality of
ADD being associated with aircrafts other than the target ADD; and positioning, at the
display unit, if the display overlap exists, the target ADD on the display unit away from an
overlapping ADD from the plurality of ADD such that the target ADD is in a clutter-free
position on the display unit.
[0056] In an embodiment, when determining whether the display overlap exists, the
declutter tool is further configured to consider the plurality of ADD in a sequential manner.
[0057] In an embodiment, when positioning the target ADD, the declutter tool is
further configured to rotate the target ADD in a clockwise direction so as to achieve the
clutter-free position on the display unit.
[0058] In an embodiment, the target ADD is rotated about an angle of intersection
between the target ADD and the at least one of the plurality of ADD.

[0059] FIG. 4 shows the pictorial representation of method, in which the angle
increment of connecting line by a factor of Ѳ is represented, in accordance with an embodiment of the present disclosure. FIG. 5 shows the pictorial representation of method, in which the radius increments of connecting line by a factor of overlapping width w is represented, in accordance with an embodiment of the present disclosure. FIG. 10 shows information related to calculation of intersection label angle and intersection width, in accordance with an embodiment of the present disclosure.
[0060] In Air Traffic Control System, the ASP contains the aircraft symbols and the
Aircraft Data Descriptor (ADD) associated with these symbols. ADD displays the basic
identification information of the aircraft such as Call-sign, Unique track number, IFF code
along with kinematic parameters such as speed, course and height. Each ADD is connected
with its corresponding aircraft symbol through a connector line. The default values of length
and angle of connector line with respect to aircraft symbol is provided by the system. The
length and angle of connector line with respect to aircraft symbol can be updated manually by
the operator by repositioning the ADD on the ASP through mouse. The position of ADD is
continuously updated with the movement of aircraft and is always positioned at configured
length and angle from the aircraft symbol. These updates of ADD sometimes results in
overlapping of ADD with each other or with other aircraft present in close proximity.
[0061] The major functional requirement in this is to avoid overlapping as much as
possible to prevent obscuring of data. This requires automatic repositioning of the ADD and automatic configuration of length and angle of connector line to remove any cluttering that exists due to large number of ADDs in scope or due to multiple aircrafts in close proximity. Unlike the previous solutions available, this method provides a finite search scope and an efficient solution in comparatively less time. This approach provides efficient solution for approximately 1000 aircraft and there corresponding 1000 ADDs.
[0062] The key requirements for the better Air Situation Picture are that the ADD
shall not overlap with each other i.e. no ADD shall hide the information displayed on another ADD; and that the ADD shall not overlap another aircraft. [0063]
[0064] Hence, Air Traffic Management System (ATMS) has been conceptualized as
one of the most advanced automated air traffic control systems which meet international standards and recommended practices in air traffic management. This ATMS System is designed with state-of-art algorithm and design methodologies for providing 24x7 Operations, High- Availability, Fail-Safe system comprising of Data Processing systems,

Controller Display systems, Surveillance & Monitoring systems, Simulator system, Recording & Playback systems.
[0065] The Controller Working Position (CWP) is one of the most critical and
important system which provides a single point interface to the ATC operator for controlling and monitoring purpose. The Air Situation Picture (ASP) displayed on CWP is composed of synthetic symbol of aircraft, surveillance zones, local flying areas and controller sectors provides synthetic augmentation to controller’s vision and aids in effective and efficient controlling of en-route aircraft.
[0066] ADD displays the basic identification information of the aircraft such as call-
sign, unique track Number, IFF code along with kinematic parameters such as speed, course and height. The location of ADD is associated with the current position of the aircraft. The continuous change in the position of the aircraft may lead to overlapping of ADD with other ADDs or with other aircrafts and may obscure important information from the operator. Negligence in any data in ASP might lead to catastrophic situations. To mitigate any such scenario, there arises a requirement to develop a mechanism that avoids this overlapping and hiding of important information. Hence, “Method for Real Time Object Label Overlap Avoidance for Air Traffic Control System” has been developed which provides a clear overlap free picture of ASP to controller. This method makes use of the angle that ADD makes with aircraft and the radius of ADD from aircraft to find feasible position of ADD in order to avoid overlaps.
[0067] The present disclosure thus provides a method for real time object label
overlap avoidance for air traffic control system which provides a clear overlap free picture of ASP to controller. This method makes use of the angle that ADD makes with aircraft and the radius of ADD from aircraft to find feasible position of ADD in order to avoid overlaps. ATMS System is designed with state-of-art algorithm and design methodologies for providing 24x7 Operations, High-Availability, Fail-Safe system comprising of Data Processing systems, Controller Display systems, Surveillance & Monitoring systems, Simulator system, Recording and Playback systems. The Controller Working Position (CWP) is one of the most critical and important system which provides a single point interface to the ATC operator for controlling and monitoring purpose.
[0068] The present disclosure provides an experimentally tested method which
ensures the avoidance of object label overlaps in real time scenarios for Air Traffic Control System with the efficient and practically feasible approach.

[0069] The method disclosed in the present invention reduces the search scope for the
next available position of ADD. This has been practically tested and the results have shown that 100 iterations can remove up to 85% of overlapping.
[0070] The method is practically implemented on 1000 aircrafts and their 1000
corresponding ADDs. The solution is generated in approximate 1000 msec. The complexity of method is O (n2).
[0071] The method gives a generalized approach which makes it convenient to use in
other display applications as well.
[0072] The design of method is easy to implement.
[0073] This is a generalized Declutter Tool solution to ADD overlapping problem.
Hence can be used in any application.
[0074] This design is experimentally tested and reduces the search scope for the next
available position of ADD to a large extent. Experimental results have shown that in 100 iterations about 85% of overlapping is removed. The complexity of this method is O (n × (n-1) × (k×t)) and the results are quite efficient to use in practical situations where n, k and t are: n = No. of Aircraft; k = overlap checking complexity; t = No. of iterations; and k and t are constants so the complexity of method becomes O(n2).
ADVANTAGES OF THE PRESENT DISCLOSURE
[0075] The present disclosure provides an experimentally tested method which
ensures the avoidance of object label overlaps in real time scenarios for Air Traffic Control
System with the efficient and practically feasible approach.
[0076] The method disclosed in the present invention reduces the search scope for the
next available position of ADD. This has been practically tested and the results have shown
that 100 iterations can remove up to 85% of overlapping.
[0077] The method is practically implemented on 1000 aircrafts and their 1000
corresponding ADDs. The solution is generated in approximate 1000 msec. The complexity
of method is O (n2).
[0078] The method gives a generalized approach which makes it convenient to use in
other display applications as well.
[0079] The design of method is easy to implement.
[0080] This is a generalized Declutter Tool solution to ADD overlapping problem.
Hence can be used in any application.

[0081] This design is experimentally tested and reduces the search scope for the next
available position of ADD to a large extent. Experimental results have shown that in 100 iterations about 85% of overlapping is removed. The complexity of this method is O (n × (n-1) × (k×t)) and the results are quite efficient to use in practical situations where n, k and t are: n = No. of Aircraft; k = overlap checking complexity; t = No. of iterations; and k and t are constants so the complexity of method becomes O(n2).

We Claim:
1. An air traffic control system comprising:
a declutter tool configured to:
determine whether a display overlap exists for a target aircraft data descriptor (ADD) associated with a target aircraft on a display unit with at least one of a plurality of ADD, the plurality of ADD being associated with aircrafts other than the target ADD; and
position, if the display overlap exists, the target ADD on the display unit away from an overlapping ADD from the plurality of ADD such that the target ADD is in a clutter-free position on the display unit.
2. The air traffic control system as claimed in claim 1, wherein, when determining whether the display overlap exists, the declutter tool is further configured to consider the plurality of ADD in a sequential manner.
3. The air traffic control system as claimed in claim 1, wherein, when positioning the target ADD, the declutter tool is further configured to rotate the target ADD in a clockwise direction so as to achieve the clutter-free position on the display unit.
4. The air traffic control system as claimed in claim 3, wherein the target ADD is rotated about an angle of intersection between the target ADD and the at least one of the plurality of ADD.
5. The air traffic control system as claimed in claim 4, wherein the plurality of ADD includes one thousand ADDs.
6. A method comprising:
determining, at a declutter tool, whether a display overlap exists for a target aircraft data descriptor (ADD) associated with a target aircraft on a display unit with at least one of a plurality of ADD, the plurality of ADD being associated with aircrafts other than the target ADD; and
positioning, at the display unit, if the display overlap exists, the target ADD on the display unit away from an overlapping ADD from the plurality of ADD such that the target ADD is in a clutter-free position on the display unit.
7. The method as claimed in claim 6, wherein, when determining whether the display
overlap exists, the declutter tool is further configured to consider the plurality of ADD in a
sequential manner.

8. The method as claimed in claim 6, wherein, when positioning the target ADD, the declutter tool is further configured to rotate the target ADD in a clockwise direction so as to achieve the clutter-free position on the display unit.
9. The method as claimed in claim 8, wherein the target ADD is rotated about an angle of intersection between the target ADD and the at least one of the plurality of ADD.
10. The method as claimed in claim 9, wherein the plurality of ADD includes one thousand ADDs.