Description:TECHNICAL FIELD
[0001] The present disclosure relates generally to aviation surveillance systems. In particular, the present disclosure relates to a method and a system for tracking targets.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed disclosure, or that any publication specifically or implicitly referenced is prior art.
[0003] Multilateration (MLAT) system is a part of surveillance technology used in aviation systems to determine the location of targets such as aircrafts. MLAT systems work by measuring the time difference between the signals received at multiple ground stations that are transmitted by an aircraft’s transponder. These ground stations then use the time difference of arrival to calculate the aircraft’s location. MLAT systems are used to supplement traditional radar systems and can provide more accurate and reliable aircraft positioning data, especially in areas where radar coverage may be limited or non-existent.
[0004] Since target measurements are received asynchronously, track initiation and maintenance become challenging tasks. Specifically, since target measurements are available at asynchronous times, it is difficult to uniquely associate one set of measurements to a corresponding target or existing record of tracks associated with the target. Further, MLAT systems are inherently designed to make multiple measurements for the same target due to asynchronous update rates of transmitter/receiver devices used by the said MLAT systems. At times, multiple measurements from different receiving stations may be inconsistent and thereby not able to be uniquely associated with a target. In order to ensure a quality position and track for the target, sophisticated algorithms must be used to reconcile these inconsistencies and ensure that the received measurements are correctly associated with the target, which increases computation time and decreases responsivity.
[0005] Tracking multiple target objects further adds to the complexities of tracking aircraft in aviation. In such scenarios, several challenges arise. Firstly, it becomes difficult to associate the measurement with the correct corresponding target. Secondly, it becomes challenging to decide which of the multiple detected measurements to use for correlation. Thirdly, one must determine whether to use only one measurement or to use all the measurements. Finally, if the decision is made to use all measurements, it becomes crucial to determine how to use them effectively.
[0006] Further, additional information on the target such as aircraft identification, velocity and altitude may be needed to accurately track the target. Such data may be obtained by transmitting interrogation signals at periodic and appropriate intervals. However, there do not exist any automated systems that effectively and efficiently track the target using measurements received asynchronously.
[0007] There is, therefore, a need for a method and a system to address the above-mentioned problems.

OBJECTS OF THE INVENTION
[0008] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are listed herein below.
[0009] An object of the present disclosure is to provide a system and method for accurate track initiation and maintenance of targets such as aircrafts.
[0010] Another object of the present disclosure is to provide a system and method for associating asynchronous target measurements to corresponding tracks.
[0011] Another object of the present disclosure is to provide a system and method for effectively handling multiple measurements for the same target.
[0012] Another object of the present disclosure is to provide a system and method for tracking multiple target objects in a geographical area.
[0013] Another object of the present disclosure is to provide a system and method for tracking targets asynchronously while avoiding race conditions.
[0014] The other objects and advantages of the present disclosure will be apparent from the following description when read in conjunction with the accompanying drawings, which are incorporated for illustration of the preferred embodiments of the present disclosure and are not intended to limit the scope thereof.

SUMMARY
[0015] Aspects of the present disclosure relate generally to aviation surveillance. In particular, the present disclosure relates to a method and a system for tracking targets.
[0016] In an aspect, a system for tracking targets may include one or more transreceiver units (TRUs) distributed over one or more sectors associated with a geographical area, the TRUs being configured to broadcast one or more request signals over each of the one or more sectors, and receive one or more response signals from one or more targets in said one or more sectors. The system may also include a data processing unit configured to determine one or more measurement values associated with the one or more targets in the one or more sectors based on the received one or more response signals. The system may further include a target tracking unit configured to store the one or more measurement values in a first data structure, correlate the one or more measurement values with one or more tracks indicative of paths taken by each of the one or more targets, the one or more tracks being retrieved from a track storage unit, and update the one or more tracks based on the correlated one or more measurement values.
[0017] In an embodiment, to store the one or more measurement values, the data processing unit may be configured to create a first data structure having a first data store and a second data store for storing the one or more measurement values, and a second data structure having one or more sets of flags corresponding to the number of sectors. Further, the data processing unit may determine a sector index corresponding to the one or more sectors based on the one or more measurement values from the data processing unit, store the one or more measurement values in either the first data store or the second data store based on the one or more sets of flags from the second data structure corresponding to the determined sector index. The data processing unit may be further configured to update one or more flags from the one or more sets of flags indicating whether the one or more measurement values are to be stored in either the first data store or the second data store, and whether the one or more measurements are to be retrieved from the first data store or second data store for processing such that the one or more measurement are stored and processed in mutual exclusion.
[0018] In an embodiment, to correlate the one or more measurement values with the one or more tracks, the target tracking unit may be configured to select a sector from the one or more sectors for processing, and retrieve the one or more measurement values associated with the selected sector and the one or more sectors neighbouring the selected sector based on the one or more flags associated with the selected sector in the second data structure. The target tracking unit may further correlate the one or more retrieved measurement values with the one or more tracks retrieved from the track storage unit either by comparing the mode code in the retrieved one or more measurement values with the mode codes associated with the one or more tracks.
[0019] In an embodiment, to update the one or more tracks, the target tracking unit may be configured to create one or more new tracks in the track storage unit based on the one or more measurement values if the one or more measurement values are not correlated with the one or more tracks in the track storage unit. The target tracking unit may process the one or more measurement values by any one or more of track smoothening, track maintenance, track position identification and track kinematics calculation, based on the one or more measurement values and update the one or more tracks with the processed one or more measurement values. Further, the target tracking unit may delete one or more existing tracks from the one or more tracks if said one or more existing tracks may be either inactive or associated with targets that may be exiting the geographical surveillance area.
[0020] In an embodiment, the system may include an interrogation scheduler unit configured to store the one or more tracks in a third data structure, the one or more tracks in the third data structure being sorted based on the distance between the one or more targets and a reference location in the geographical area. The interrogation scheduler unit may select a target from the one or more targets that require one or more additional measurement values associated with said selected target. Further, the interrogation unit may cause the one or more TRUs to transmit one or more interrogation signals to the selected targets and receive the one or more response signals having the additional measurement values from the selected target. The interrogation unit may also adjust the frequency at which the one or more interrogation signals may be transmitted by comparing the number of targets to be interrogated by each of the one or more TRUs with predetermined threshold.
[0021] In an embodiment, the system may include a squitter generator unit configured to transmit one or more squitter signals to the one or more TRUs so as to ensure temporal synchronization between each of the one or more TRUs.
[0022] In an aspect, a method for tracking targets may include broadcasting, by one or more transreceiver unit (TRU) distributed over one or more sectors associated with a geographical area, one or more request signals over each of the one or more sectors, receiving, by the one or more TRUs one or more response signals from one or more targets in said one or more sectors. The method may include determining, by a data processing unit, one or more measurement values associated with the one or more targets in the one or more sectors based on the received one or more response signals. The method may further include storing, by a target tracking unit, the one or more measurement values in a first data store or a second data store based on the one or more sets of flags stored in a second first data structure. The method may also include correlating, by the target tracking unit, the one or more measurement values with one or more tracks indicative of paths taken by each of the one or more targets, the one or more tracks being retrieved from a track storage unit, and updating, by the target tracking unit, the one or more tracks based on the correlated one or more measurement values.
[0023] In an embodiment, storing the one or more measurement values may include, creating the first data structure having a first data store and a second data store for storing the one or more measurement values, and a second data structure having one or more sets of flags corresponding to the number of sectors. The method may include determining a sector index corresponding to the one or more sectors based on the one or more measurement values received from the data processing unit. Further, the method may include storing the one or more measurement values in either the first data store or the second data store based on the one or more sets of flags corresponding to the determined sector index, and updating one or more flags from the one or more sets of flags indicating whether the one or more measurement values are to be stored in either the first data store or the second data store, and whether the one or more measurements are to be retrieved from the first data store or second data store for processing such that the one or more measurement are stored and processed in mutual exclusion.
[0024] In an embodiment, correlating the one or more measurement values with the one or more tracks may include, selecting a sector from the one or more sectors for processing. The method may include retrieving the one or more measurement values associated with the selected sector and the one or more sectors neighbouring the selected sector based on the one or more flags associated with the selected sector in the second data structure. The method may further include correlating the one or more retrieved measurement values with the one or more tracks retrieved from the track storage unit either by comparing the mode codes in the retrieved one or more measurement values with the mode codes associated with the target corresponding to the one or more tracks.
[0025] In an embodiment, updating the one or more tracks may include creating, by the target tracking unit, one or more new tracks based on the one or more measurement values if the one or more measurement values may be not correlated with the one or more tracks in the track storage unit. The method may include processing, by the target tracking unit, the one or more measurement values by any one or more of track smoothening, track maintenance, track position identification and calculating track kinematics, based on the one or more measurement values and updating the one or more tracks with the processed one or more measurement values. The method may further include deleting one or more existing tracks from the one or more tracks if said one or more existing tracks may be either inactive or associated with targets that may be exiting the geographical surveillance area.
[0026] In an embodiment, the method may include storing, by an interrogation scheduler unit, the one or more tracks in a third data structure, the one or more tracks in the third data structure being sorted based on the distance between the one or more targets and a reference location in the geographical area. The method may further include selecting, by the interrogation scheduler unit, a target from the one or more targets that require one or more additional measurement values associated with said selected target. The method may also include causing, by the interrogation scheduler unit, the one or more TRUs to transmit one or more interrogation signals to the selected targets and receiving the one or more response signals having the additional measurement values from the selected target. The method may further include adjusting, by the interrogation scheduler unit, the frequency at which the one or more interrogation signals may be transmitted by comparing the number of targets to be interrogated by each of the one or more TRUs with a predetermined threshold.
[0027] In an embodiment, the method may include transmitting, by a squitter generator unit, one or more squitter signals to the one or more TRUs so as to ensure temporal synchronization between each of the one or more TRUs.
[0028] 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
[0029] 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.
[0030] FIG. 1 illustrates an exemplary network architecture for implementing a proposed system, according to embodiments of the present disclosure.
[0031] FIG. 2 illustrates an exemplary block diagram representation of the proposed system, according to embodiments of the present disclosure.
[0032] FIG. 3 illustrates a flow chart depicting a method for tracking targets, according to embodiments of the present disclosure.
[0033] FIG. 4 illustrates a flow chart depicting a method for updating the one or more tracks, according to embodiments of the present disclosure.
[0034] FIG. 5 illustrates a flow chart depicting a method for scheduling interrogation signals, according to embodiments of the present disclosure.
[0035] The foregoing shall be more apparent from the following more detailed description of the invention.

DETAILED DESCRIPTION
[0036] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address all of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.
[0037] The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It should be understood that, various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth.
[0038] Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practised without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.
[0039] Also, it is noted that individual embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in a figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination can correspond to a return of the function to the calling function or the main function.
[0040] The word “exemplary” and/or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and/or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising” as an open transition word without precluding any additional or other elements.
[0041] As used herein, “connect,”“configure,”“couple,” and its cognate terms, such as “connects,”“connected,”“configured,” and “coupled” may include a physical connection (such as a wired/wireless connection), a logical connection (such as through logical gates of semiconducting device), other suitable connections, or a combination of such connections, as may be obvious to a skilled person.
[0042] As used herein, “send,”“transfer,”“transmit,” and their cognate terms like “sending,”“sent,”“transferring,”“transmitting,”“transferred,”“transmitted,” etc. include sending or transporting data or information from one unit or component to another unit or component, wherein the content may or may not be modified before or after sending, transferring, transmitting.
[0043] Reference throughout this specification to “one embodiment” or “an embodiment”, or “an instance” or “one instance” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed products.
[0045] Various embodiments of the present disclosure relate generally to aviation surveillance. In particular, the present disclosure relates to a method and a system for tracking targets.
[0046] In an aspect, a system for tracking targets may include one or more transreceiver units (TRUs) distributed over one or more sectors associated with a geographical area, the TRUs configured to, broadcast one or more request signals over each of the one or more sectors, and receive one or more response signals from one or more targets in said one or more sectors. The system may also include a data processing unit configured to determine one or more measurement values associated with the one or more targets in the geographical area based on the received one or more response signals. The system may further include a target tracking unit configured to, store the one or more measurement values in a first data structure, correlate the one or more measurement values with one or more tracks indicative of paths taken by each of the one or more targets, the one or more tracks being retrieved from a track storage unit, and update the one or more tracks based on the correlated one or more measurement values.
[0047] FIG. 1 illustrates an exemplary network architecture 100 for implementing a proposed system 110, according to embodiments of the present disclosure. The network architecture 100 may include a system 110 having a data processing unit 106, a target tracking unit 107, and interrogation scheduler unit 109, and a track storage 108. The network architecture 100 may also include one or more transreceiver units 102-1 and 102-2 (collectively referred to as TRUs 102). The network architecture 100 may also include one or more receiver units 103-1 and 103-2 (collectively referred to as RUs 103). The network architecture 100 may further include a squitter generator unit 105 The system 110 may be connected to each of the TRUs 102 and the RUs 103 via a communication means 104-1 and 104-2 (collectively referred to as communication means 104) respectively.
[0048] In an embodiment, the system 110 may be configured to ascertain and track positions of one or more targets in a geographical region. In an embodiment, the targets may be air targets including, but not limited to, aircrafts, helicopters, unmanned aerial vehicles, missiles, and the like, or ground targets including, but not limited to, automobiles, trains, ships, and the like. In an embodiment, each of the one or more targets may include a transponder unit configured to transmit one or more response signals on receiving one or more request signals.
[0049] In an embodiment, the one or more TRUs 102 are configured to broadcast and receive signals from a target from the one or more air and ground targets. In an embodiment, the one or more TRUs 102 may be distributed across one or more sectors of the geographical area subject to air traffic surveillance. In an embodiment, the one or more TRUs 102 may broadcast one or more request signals over each of the one or more sectors. In an embodiment, the network architecture 100 may also include the one or more RUs 103 configured to receive signals from the one or more targets. In an embodiment, at least one of the one or more TRUs 102 may be the one or more RUs 103 distributed over the geographical area. In an embodiment, the one or more TRUs 102 may be configured to receive the one or more response signals from the one or more targets in the geographical area. In an embodiment, the TRUs 102 may redirect the signals received from the one or more targets to the data processing unit 106. In an embodiment, the one or more response signals may be in accordance with the one or more standard response codes including, but not limited to, Mode-1, Mode-2, Mode-3A, Mode-C, Mode-S codes.
[0050] In an embodiment, the data processing unit 106 may determine one or more measurement values associated with the one or more targets based on the one or more response signals. In an embodiment, the one or more measurement values determined may include, but not limited to, unique ID, height, location, velocity, altitude, binary data store (BDS) information, azimuth value, range, mode code and the like, associated with the target. In an embodiment, the data processing unit 106 may determine including, but not limited to, the longitude, latitude and altitude of the one or more targets with respect to the geographical area. In an embodiment, the data processing unit 106 may determine the one or more measurement values using multilateration based on the one or more response signals received by the one or more TRUs 102. In an embodiment, the one or more measurement values may be determined by solving the intersection of hyperbolas based on time difference of arrival (TDOA) of the one or more response signals at each of the one or more TRUs 102. In an embodiment, the data processing unit 106 may determine the one or more measurement values asynchronously.
[0051] In an embodiment, the data processing unit 106 may transmit the one or more measurement values to the target tracking unit 107. In an embodiment, the target tracking unit 107 may store the received one or more measurement values in a first data structure. In an embodiment, the first data structure may include a first data store and a second data store for storing the one or more measurement values, and a second data structure may include one or more sets of flags corresponding to number of sectors. In an embodiment, the one or more sets of flags may include a set of storage flags and a set of process flags. In an embodiment, to store the one or more measurement values, the target tracking unit 107 may be configured to determine a sector index corresponding to the one or more sectors based on the one or more measurement values. In an embodiment, the target tracking unit 107 may store the one or more measurement values in either the first data store or the second data store based on the one or more flags associated with the determined sector index. In an embodiment, the target tracking unit 107 may update one or more flags from the one or more sets of flags indicating whether the one or more measurement values are to be stored in either the first data store or the second data store, and whether the one or more measurements are to be retrieved from the first data store or second data store for processing such that the one or more measurement are stored and processed in mutual exclusion.
[0052] In an embodiment, the target tracking unit 107 may correlate the one or more measurement values with one or more tracks indicative of paths taken by each of the one or more targets. In an embodiment, the one or more tracks may be stored in the track storage unit 108. In an embodiment, to correlate the one or more measurement, the target tracking unit 107 may select a sector from the one or more sectors for processing. The target tracking unit 107 may then retrieve the one or more measurement values associated with the selected sector and the one or more sectors neighbouring the selected sector based on the one or more flags in the one or more sets of flags. In an embodiment, the target tracking unit 107 may correlate the one or more retrieved measurement values with the one or more tracks retrieved from the track storage unit 108 either by comparing the mode codes in the retrieved one or more measurement values with the mode codes associated with the target corresponding to the one or more tracks. In an embodiment, the one or more measurement values may be correlated with any one of the one or more tracks using an association algorithm including, but not limited to, global nearest neighbour algorithm.
[0053] In an embodiment, the target tracking unit 107 may be configured to update the one or more tracks based on the one or more measurement values. In an embodiment, one or more new tracks may be created in the track storage unit 108 based on the one or more measurement values if the one or more measurement values are not correlated with the one or more tracks in the track storage unit 108. In an embodiment, the target tracking unit 107 may process the one or more measurement values by any one or more of track smoothening, track maintenance, track position identification and track kinematics calculation, based on the one or more measurement values and update the one or more tracks with the processed one or more measurement values. In other embodiments, the target tracking unit 107 may delete one or more existing tracks from the one or more tracks if said one or more existing tracks are either inactive or associated with targets that are exiting the geographical surveillance area.
[0054] In an embodiment, the track storage unit 108 may store the one or more tracks created and updated by the target tracking unit 107. In an embodiment, the one or more tracks may be stored in a third data structure. In an embodiment, the third data structure may be indicative of a priority list. In an embodiment, the interrogation scheduler unit 109 may be configured to store the one or more tracks in a third data structure, the one or more tracks in the third data structure being sorted based on the distance between the one or more targets and a reference location in the geographical area. In an embodiment, the reference location may be indicative of including, but not limited to taxiways, airports, air traffic controllers, and the like, in the geographical area. In an embodiment, the interrogation scheduler unit 109 may select one or more targets from the third data structure that requires one or more additional measurement values associated with said selected target. In an embodiment, the interrogation scheduler unit 109 may cause the one or more TRUs 102 to transmit one or more interrogation signals to the selected one or more targets. In such embodiments, the one or more TRUs 102 or one or more RUs 103 may receive the one or more response signals having the additional measurement values. In an embodiment, the interrogation scheduler unit 109 may adjust the frequency at which the one or more interrogation signals are transmitted based on traffic or number of target interrogations associated with each of the one or more TRUs 102. In an embodiment, if the traffic associated with any one of the selected TRUs 102 exceeds a predetermined threshold, the interrogation frequency of the selected TRU 102 may be reduced.
[0055] In an embodiment, the squitter generator unit 105 may be configured to transmit one or more squitter signals to the one or more TRUs 102. In an embodiment, the squitter generator unit 105 may ensure that the one or more TRUs 102 have temporal synchronization between each of the said one or more TRUs 102.
[0056] In an embodiment, the communication means 104 may be a wired communication network or a wireless communication network. In an embodiment, wireless communication means may be any wireless communication network capable of transferring data between entities of that network including, but are not limited to, a Bluetooth, a Zigbee, a Near Field Communication (NFC), a Wireless-Fidelity (Wi-Fi) network, a Light Fidelity (Li-FI) network, a carrier network including a circuit-switched network, a packet switched network, a Public Switched Telephone Network (PSTN), a Content Delivery Network (CDN) network, an Internet, intranets, Local Area Networks (LANs), Wide Area Networks (WANs), mobile communication networks including a Second Generation (2G), a Third Generation (3G), a Fourth Generation (4G), a Fifth Generation (5G), a Sixth Generation (6G), a Long-Term Evolution (LTE) network, a New Radio (NR), a Narrow-Band (NB), an Internet of Things (IoT) network, a Global System for Mobile Communications (GSM) network and a Universal Mobile Telecommunications System (UMTS) network, combinations thereof, and the like. In an embodiment, wired communication means may include, but not be limited to, ethernet connection, optical link connection, USB connection, cable connection, fibre connection, or combinations thereof.
[0057] In an embodiment, the system 110 may be implemented by way of a single device or a combination of multiple devices that may be operatively connected or networked together. For example, the system 110 may be implemented by way of a standalone device and may be communicatively coupled to an electronic device. In yet another example, the system 110 may be implemented in/associated with respective one or more computing devices. In an embodiment, the electronic device and/or the computing devices may be at least one of an electrical, an electronic, an electromechanical, and a computing device. The electronic device and/or the computing devices may include, but is not limited to, a mobile device, a smart-phone, a Personal Digital Assistant (PDA), a tablet computer, a phablet computer, a wearable computing device, a Virtual Reality/Augmented Reality (VR/AR) device, a laptop, a desktop, a server, and the like.
[0058] In an embodiment, the system 110 may be implemented in hardware or a suitable combination of hardware and software. The system 110 may be associated with entities (not shown).
[0059] Further, the system 110 may include one or more processors 112, an Input/Output (I/O) interface 114, and a memory 116. In an embodiment, each of the data processing unit 106, the target tracking unit 107 and the interrogation scheduler unit 109 may be associated with the at least one of the one or more processors 112. The I/O interface 114 of the system 110 may be used to receive user inputs from the computing devices 104 associated. Further, the system 110 may also include other units such as a display unit, an input unit, an output unit, and the like, however the same are not shown in FIG. 1, for the purpose of clarity. Also, in FIG. 1, only a few units are shown, however, the system 110 or the network architecture 100 may include multiple such units or the system 110/network architecture 100 may include any such numbers of the units, obvious to a person skilled in the art or as required to implement the features of the present disclosure.
[0060] In an embodiment, the system 110 may be a hardware device including the one or more processors 112 executing machine-readable program instructions to translation models in a computing environment. Execution of the machine-readable program instructions by the one or more processors 112 may enable the proposed system 110 to train translation models. The “hardware” may comprise a combination of discrete components, an integrated circuit, an application-specific integrated circuit, a field programmable gate array, a digital signal processor, or other suitable hardware. The “software” may comprise one or more objects, agents, threads, lines of code, subroutines, separate software applications, two or more lines of code, or other suitable software structures operating in one or more software applications or on one or more processors. The one or more processors 112 may include, for example, but is not limited to, microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and any devices that manipulate data or signals based on operational instructions, and the like. Among other capabilities, the one or more processors 112 may fetch and execute computer-readable instructions in the memory 116 operationally coupled with the system 110 for performing tasks such as data processing, input/output processing, feature extraction, and/or any other functions. Any reference to a task in the present disclosure may refer to an operation being or that may be performed on data.
[0061] In an embodiment, a non-transitory computer-readable medium for tracking targets may include processor-executable instructions that cause one or more processors to perform the steps of the method disclosed herein.
[0062] FIG. 2 illustrates an exemplary block diagram representation of the proposed system 110, according to embodiments of the present disclosure.
[0063] In an embodiment, the processing unit 118 may include the data processing unit 106, the target tracking unit 107, the track storage unit 108, the interrogation scheduler unit 109 and other units 120. In an embodiment, each of the processing units 118 may include one or more modules stored within the memory 116. In an example, the modules, communicatively coupled to the one or more processors 112 configured in the system 110, may also be present outside the memory 116, as shown in FIG. 2, and implemented as hardware. As used herein, the term modules may refer to an Application-Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.
[0064] In an embodiment, the data processing unit 106 may include a receiving module that received the one or more response signals from the one or more targets. Further, the data processing unit 106 may include a determination unit that determined the one or more measurement values from the one or more response signals. In an embodiment, the determination unit may determine including, but not limited to, unique ID, height, location, velocity, altitude, binary data store (BDS) information, and the like, associated with the target.
[0065] In an embodiment, the target tracking unit 107 may include a data storing module to receive measurement values from the data processing unit 106 asynchronously. In an embodiment, the data storing module may store the one or more measurement values in the first data store or the second data store indicative of an array of linked lists based on the one or more flags in the second data structure indicative of an array. In an embodiment, the first data structure may allow the one or more measurement values to be stored and processed in a mutually exclusive manner. In an embodiment, the target tracking unit 107 may include a correlation module for correlating the one or more measurement values to the one or more tracks in the track storage unit 108. In an embodiment, the correlation module may correlate the one or more measurement values with the one or more tracks by comparing the mode code in said one or more measurement values with mode codes associated with the one or more targets corresponding to each of the one or more tracks. In an embodiment, the target tracking unit 107 may also include a processing module for smoothening the track position and determining track kinematics. In an embodiment, the target tracking unit 107 may also include an updation module to update the one or more tracks based on the measurement values processed by the processing modules.
[0066] In an embodiment, the interrogation scheduler module 109 may include a creation module for creating and storing a third data structure indicative of a priority list of targets. In an embodiment, the creation module may sort the one or more targets in the priority list based on the distance said one or more targets from the reference point in the geographical region. In an embodiment, the interrogation scheduler module 109 may include a scheduler module for causing the one or more TRUs 102 to transmit the one or more interrogation signals to the targets for obtaining additional measurement values. In an embodiment, the interrogation scheduler 109 may also include a frequency updation module to update the interrogation frequency of TRUs 102 based on the number of targets to be interrogated by each TRU 102.
[0067] FIG. 3 illustrates a flow chart depicting a method 200 for tracking targets, according to embodiments of the present disclosure.
[0068] In an embodiment, target tracking unit 107 may be configured to receive the one or more measurement values, correlate the received measurement values with the one or more tracks corresponding to the one or more targets, using the method 200.
[0069] At step 202, the method 200 may include creating the second data structure having one or more sets of flags, and a first data structure having first data store and a second data store for storing the one or more measurement values. In an embodiment, the second data structure may be indicative of an array and the first data structure may be indicative of an array of linked lists. In an embodiment, the second data structure may include a set of storage flags of size ‘N’ and a set of process flags of size ‘N’, thereby having a cumulative size ‘2N’. Here, ‘N’ may be indicative of the number of sectors in the geographical area. In an example, the second data structure may include an ODD_EVEN storage flag indicative of the set of storage flags, the ODD_EVEN storage flag being used for determining whether the received one or more measurement values are to be stored in an ODD storage indicative of the first data store or an EVEN storage indicative of the second data store. In such examples, the second data structure may also include an ODD_EVEN process flag indicative of the set of process flags, the ODD_EVEN process flag being used to determine whether the one or more measurement values are to be collected from ODD storage or EVEN storage for processing. In an embodiment, the one or more flags in the one or more sets of flags may be initialized to a default value. In the foregoing example, the ODD_EVEN storage flags may be set to ODD or 0, and the ODD_EVEN process flags may be set to EVEN or 1.
[0070] At step 203, the method 203 may include determining, by the target tracking unit 107, a sector index corresponding to the one or more sectors based on the one or more measurement values received from the data processing unit 106. In an embodiment, the data processing unit 106 may determine the one or more measurement values based on including, but not limited to, the range, azimuth and mode code information from the one or more response signals.
[0071] At step 204, the method 200 may include storing the one or more measurement values in either the first data store or the second data store based on the one or more sets of flags associated with the determined sector index. In the foregoing example, the one or more measurement values may be stored in the [o][n] index of the first data structure, where ‘n’ is indicative of the sector index to which the target belongs, and ‘o’ is the ODD_EVEN storage flag associated with the sector ‘n’. The method 200 may also include updating one or more flags from the one or more sets of flags indicative of whether the one or more measurement values are stored in either the first data store or the second data store. Further, the one or more flags may also indicate whether the one or more measurement values are to be processed from either the second data store or the first data store, whereby the one or more measurement are stored and processed in mutual exclusion. In the foregoing example, the target tracking unit 107 may segregate the one or more measurement values to a corresponding sector represented by the flag in the ODD_EVEN storage flag.
[0072] At step 205, the method 200 may include selecting a sector from the one or more sectors for processing. In an embodiment, the correlation may be timer-based that runs for ‘S’ seconds during which the system 110 receives the one or more measurement values. In an embodiment, the processing time available to cover each of the sectors may be ‘S/N’ seconds, where ‘N’ is the total number of sectors.
[0073] At step 206, the method 200 may include retrieving the one or more measurement values associated with the selected sector and the one or more sectors neighbouring the selected sector based on the one or more flags associated with the selected sector in the second data structure. In an embodiment, the one or more neighbouring sectors may be sectors with indices that are one or more indices away from the index associated with the selected sector. For example, if the index associated with the selected sector is ‘N’, the indices associated with the one or more neighbouring sectors may be N-1, N+1, N-2, N+2, and so on. In the foregoing example, at step 206, considering 64 sectors, when the timer is initiated, the method 200 may include retrieving the one or more measurement values from 1st sector, and while doing so, retrieving the one or more measurement values associated with 63rd, 64th, 2nd and 3rd sectors. In an embodiment, the method 200 may allow for mutual exclusion between storing and processing the one or more measurement values from same sectors. In an embodiment, while processing the one or more measurements stored in the first data store associated with the first sector, the storage flag associated with the first sector is set corresponding to the second data store, and vice versa in other embodiments. In such embodiments, the one or more measurement values may not be stored to and processed from the same data store, thereby allowing the one or more measurement values to be stored and processed in a mutually exclusive manner.
[0074] In the foregoing example, by toggling the ODD_EVEN storage flag and ODD_EVEN process flag for the subsequent 2 sectors, the method 200 avoids any race conditions associated with asynchronously storing and retrieving the one or more measurement values from the first data structure. In an embodiment, the target tracking unit 107 may correlate the one or more retrieved measurement values with the one or more tracks retrieved from the track storage unit 108 either by comparing the mode codes in the retrieved one or more measurement values with the mode codes associated with the target corresponding to the one or more tracks or using any association algorithms.
[0075] At step 207, the method 200 may include correlating, by the target tracking unit 107, the one or more measurement values with one or more tracks indicative of paths taken by each of the one or more targets, the one or more tracks being retrieved from a track storage unit 108. In the foregoing example, the steps 205-206 may be repeated for each of the ‘s’ sectors where while processing the sector ‘s’, the ODD_EVEN Storage and ODD_EVEN Process flag for sector ‘s+2’ is toggled as depicted in step 207.
[0076] In an embodiment, the method 200 may include performing steps 203-204, and steps 205-207 asynchronously and in parallel.
[0077] FIG. 4 illustrates a flow chart depicting a method 300 for updating the one or more tracks, according to embodiments of the present disclosure.
[0078] At step 301, the correlating the one or more retrieved measurement values with the one or more tracks based on one or more measurement values from the first data structure corresponding to one or more flags from the second data structure associated with the selected sector and the neighbouring sectors. In an example, the target tracking unit 107 may use the one or more measurement values associated with the selected sectors and the neighbouring sectors based on status of the ODD_EVEN Process flag and the one or more tracks present in the track storage unit 108 for correlating the one or more measurement values with the target. In the foregoing example, when the processing sector index is ‘N’, the one or more measurement values from sectors N-2, N-1, N, N+1, and N+2 sectors, and also the one or more tracks n, n+1, and n+2 present in the track storage unit 108 may be used for correlation. In an embodiment, the data processing unit 106 may be configured to discard duplicate measurement values associated with the selected target and retain only the latest measurement values.
[0079] In an embodiment, the target tracking unit 107 may correlate the one or more retrieved measurement values with the one or more tracks retrieved from the track storage unit 108 either by comparing the mode codes in the retrieved one or more measurement values with the mode codes associated with the target corresponding to the one or more tracks. In an embodiment, if the matching code is not found, the method 300 includes correlating the one or more measurement values using some association algorithms like but not limited to global nearest neighbour algorithm.
[0080] At step 302, the method 300 includes checking if the one or more measurement values are correlated with the track corresponding to the identified target. At step 303, the method 300 may use the one or more measurement values to update the track and smoothen the track position and track kinematics. At step 305, the method 300 may include storing the track data in track storage unit 108. In an embodiment, if the one or more measurement values are not correlated with any of the one or more tracks, the method 300, at step 304, includes creating a new track 304 and stored in the track storage unit 108.In an embodiment, the one or more tracks that are not correlated with any of the one or more measurement values are coasted until new measurement values are received from the data processing unit 106 at the next time interval. In an embodiment, if the one or more tracks are not correlated within a predetermined expiry time, the non-correlated tracks are deleted and removed from the track storage unit 108.
[0081] FIG. 5 illustrates a flow chart depicting a method 400 for scheduling interrogation signals, according to embodiments of the present disclosure.
[0082] In an embodiment, the interrogation scheduler unit 109 may be configured to adjust the frequency at which the one or more interrogation signals may be transmitted to the one or more targets. In an embodiment, the interrogation scheduler 109 may induce the one or more TRUs 102 to transmit the one or more interrogation signals to the target based on a requirement of additional measurement values.
[0083] At step 402, the method 400 includes initiating the interrogation scheduler unit 109. In an embodiment, the interrogation scheduler unit 109, on initiation, causes the one or more TRUs 102 to transmit the one or more interrogation signals and adjusts the frequency at which the one or more interrogation signals are transmitted asynchronously, or in parallel.
[0084] At step 403, the method 400 may include retrieving, by the interrogation scheduler unit 109 the one or more tracks from the track storage unit 108. At step 404, the method 400 may by comparing a predetermined threshold ‘T’ with the number of targets to be interrogated by each of the one or more TRUs 102. At step 405, if the number of targets to be interrogated by the TRU 102 is greater than ‘T’, the method 400 may include adjusting by decreasing the frequency at which the one or more interrogation signals are transmitted. At step 406, if the number of targets tracked by the TRU 102 is less than or equal to ‘T’, the method 400 may include retaining the frequency at which the one or more interrogation signals are transmitted.
[0085] At step 407, the method 400 may include storing, by an interrogation scheduler unit 109, the one or more tracks in a third data structure, the one or more tracks in the third data structure being sorted based on the distance between the one or more targets and a reference location in the geographical area. In an embodiment, the third data structure may be indicative of a priority list. In an embodiment, the priority list may be dynamically updated. At step 408, the method 400 may include selecting, by the interrogation scheduler unit 109, a target from the one or more targets. At step 409, the method 400 may include determining whether the selected target requires one or more additional measurement values. In an example, the one or more additional measurement values may include, but not be limited to, Mode3A code, Mode-S information (altitude, aircraft id, speed and other Mode-S related information) of the selected target is unavailable. At step 410, if the selected target requires the one or more additional measurement values, the method 400 may include causing the one or more TRUs 102 to transmit the one or more interrogation signals to the selected target. At step 411, if the one or more additional measurement values are available, the method 400 may include skipping the selected target and returning to step 408.
[0086] The order in which the methods 200, 300 and 400 are described is not intended to be construed as a limitation, and any number of the described method blocks may be combined or otherwise performed in any order to implement the methods 200, 300 and 400 or alternate methods. Additionally, individual blocks or steps may be deleted from the methods 200, 300 and 400 without departing from the scope of the present disclosure described herein. Furthermore, the methods 200, 300 and 400 may be implemented in any suitable hardware, software, firmware, or a combination thereof that exists in the related art or that is later developed. The methods 200, 300 and 400 describe, without limitation, the implementation of the system 110. A person of skill in the art will understand that methods 200, 300 and 400 may be modified appropriately for implementation in various manners without departing from the scope of the disclosure.
[0087] The present disclosure, therefore, solves the need for a method and a system for tracking targets.
[0088] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0089] The present disclosure provides a system and method for accurate track initiation and maintenance of targets such as aircrafts.
[0090] The present disclosure provides a system and method for associating asynchronous target measurements to corresponding tracks.
[0091] The present disclosure provides a system and method for effectively handling multiple measurements for the same target.
[0092] The present disclosure provides a system and method for tracking multiple target objects in a geographical area.
[0093] The present disclosure provides a system and method for tracking targets asynchronously while avoiding race conditions.
, Claims:1. A system (110) for tracking targets, the system (110) comprises:
one or more transreceiver units (TRUs) (102) distributed over one or more sectors associated with a geographical area, the one or more TRUs (102) configured to:
broadcast one or more request signals over each of the one or more sectors; and
receive one or more response signals from one or more targets in said one or more sectors;
a data processing unit (106) configured to determine one or more measurement values associated with the one or more targets in the one or more sectors based on the received one or more response signals; and
a target tracking unit (107) configured to:
store the one or more measurement values in a first data structure;
correlate the one or more measurement values with one or more tracks indicative of paths taken by each of the one or more targets, the one or more tracks being retrieved from a track storage unit (108); and
update the one or more tracks based on the correlated one or more measurement values.
2. The system (110) as claimed in claim 1, wherein to store the one or more measurement values, the target tracking unit (107) is configured to:
create the first data structure having a first data store and a second data store for storing the one or more measurement values, and a second data structure having one or more sets of flags corresponding to number of sectors;
determine a sector index corresponding to the one or more sectors based on the one or more measurement values from the data processing unit (106);
store the one or more measurement values in either the first data store or the second data store based on the one or more set of flags associated with the determined sector index; and
update one or more flag from the one or more sets of flags indicating whether the one or more measurement values are to be stored in either the first data store or the second data store, and whether the one or more measurements are to be retrieved from the first data store or second data store for processing such that the one or more measurement are stored and processed in mutual exclusion.
3. The system (110) as claimed in claim 1, wherein to correlate the one or more measurement values with the one or more tracks, the target tracking unit (107) is configured to:
select a sector from the one or more sectors for processing;
retrieve the one or more measurement values associated with the selected sector and the one or more sectors neighbouring the selected sector based on the one or more flags associated with the selected sector in the second data structure; and
correlate the one or more retrieved measurement values with the one or more tracks retrieved from the track storage unit (108) either by comparing the mode code in the retrieved one or more measurement values with the mode codes associated with the one or more tracks.
4. The system (110) as claimed in claim 1, wherein to update the one or more tracks, the target tracking unit (107) is configured to:
create one or more new tracks in the track storage unit(108) based on the one or more measurement values if the one or more measurement values are not correlated with the one or more tracks in the track storage unit (108);
process the one or more measurement values by any one or more of track smoothening, track maintenance, track position identification and track kinematics calculation, based on the one or more measurement values and update the one or more tracks with the processed one or more measurement values; and
delete one or more existing tracks from the one or more tracks if said one or more existing tracks are either inactive or associated with targets that are exiting the geographical surveillance area.
5. The system (110) as claimed in claim 1, wherein the system (110) comprises an interrogation scheduler unit (109) configured to:
store the one or more tracks in a third data structure, the one or more tracks in the third data structure is sorted based on the distance between the one or more targets and a reference location in the geographical area;
select a target from the one or more targets that require one or more additional measurement values associated with said selected target;
cause the one or more TRUs (102) to transmit one or more interrogation signals to the selected targets and receiving the one or more response signals having the additional measurement values from the selected target; and
adjust the frequency at which the one or more interrogation signals are transmitted by comparing the number of targets to be interrogated by each of the one or more TRUs (102) with a predetermined threshold.
6. The system (110) as claimed in claim 1, wherein the system (110) comprises a squitter generator unit (105) configured to transmit one or more squitter signals to the one or more TRUs (102) so as to ensure temporal synchronization between each of the one or more TRUs(102).
7. A method for tracking targets, the method comprising:
broadcasting, by one or more transreceiver unit (TRU) (102) distributed over one or more sectors associated with a geographical area, one or more request signals over each of the one or more sectors;
receiving, by the one or more TRUs (102), one or more response signals from one or more targets in said one or more sectors;
determining, by a data processing unit (106), one or more measurement values associated with the one or more targets in the one or more sectors based on the received one or more response signals;
storing, by a target tracking unit (107), the one or more measurement values in a first data structure;
correlating, by the target tracking unit (107), the one or more measurement values with one or more tracks indicative of paths taken by each of the one or more targets, the one or more tracks being retrieved from a track storage unit (108); and
updating, by the target tracking unit (107), the one or more tracks based on the correlated one or more measurement values.
8. The method as claimed in claim 7, wherein storing the one or more measurement values comprises:
creating the first data structure having a first data store and a second data store for storing the one or more measurement values, and a second data structure having one or more sets of flags corresponding to number of sectors;
determining a sector index corresponding to the one or more sectors based on the one or more measurement values received from the data processing unit (106);
storing the one or more measurement values in either the first data store or the second data store based on the one or more sets of flags associated with the determined sector index; and
updating one or more flags from the one or more sets of flags indicating whether the one or more measurement values are to be stored in either the first data store or the second data store, and whether the one or more measurements are to be retrieved from the first data store or second data store for processing such that the one or more measurement are stored and processed in mutual exclusion.
9. The method as claimed in claim 7, wherein correlating the one or more measurement values with the one or more tracks comprises:
selecting a sector from the one or more sectors for processing;
retrieving the one or more measurement values associated with the selected sector and the one or more sectors neighbouring the selected sector based on the one or more flags associated with the selected sector in the second data structure;
correlating the one or more retrieved measurement values with the one or more tracks retrieved from the track storage unit (108) either by comparing the mode codes in the retrieved one or more measurement values with the mode codes associated with the target corresponding to the one or more tracks.
10. The method as claimed in claim 7, wherein updating the one or more tracks comprises:
creating, by the target tracking unit (107), one or more new tracks based on the one or more measurement values if the one or more measurement values are not correlated with the one or more tracks in the track storage unit (108);
processing, by the target tracking unit (107), the one or more measurement values by any one or more of track smoothening, track maintenance, track position identification and calculating track kinematics, based on the one or more measurement values and updating the one or more tracks with the processed one or more measurement values; and
deleting one or more existing tracks from the one or more tracks if said one or more existing tracks are either inactive or associated with targets that are exiting the geographical surveillance area.
11. The method as claimed in claim 7, wherein the method comprises:
storing, by an interrogation scheduler unit (109), the one or more tracks in a third data structure, the one or more tracks in the third data structure being sorted based on the distance between the one or more targets and a reference location in the geographical area;
selecting, by the interrogation scheduler unit (109), a target from the one or more targets that require one or more additional measurement values associated with said selected target;
causing, by the interrogation scheduler unit (109), the one or more TRUs 102) to transmit one or more interrogation signals to the selected targets and receiving the one or more response signals having the additional measurement values from the selected target; and
adjusting, by the interrogation scheduler unit (109), the frequency at which the one or more interrogation signals are transmitted by comparing the number of targets to be interrogated by each of the one or more TRUs (102) with a predetermined threshold.
12. The method as claimed in claim up, wherein the method comprises: transmitting, by a squitter generator unit (105), one or more squitter signals to the one or more TRUs(102) so as to ensure temporal synchronization between each of the one or more TRUs (102).