Methods and systems for authenticating Automatic Dependent Surveillance-Broadcast (ADS-B) signals

Abstract

A method and system for authenticating Automatic Dependent Surveillance-Broadcast (ADS-B) signals. One method includes: receiving by a computing system a first authentication signal, the first authentication signal (i) identifying a first position of a first aircraft relative to a host aircraft where the computing system is located, and (ii) including a first identifier of the first aircraft; subsequently receiving a second signal, the second signal being an ADS-B signal identifying a second position, speed, and aircraft type, wherein the second signal includes a second identifier; based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, confirming using the first position and aircraft type that it is possible for the first aircraft to subsequently be located at the second position and moving at the said speed; and based on the confirmation that it is possible, providing an indication that the second signal is genuine.

Description

Technical Field

[0001] This disclosure generally relates to systems and methods for signal authentication, and more specifically, to systems and methods for authenticating Automatic Dependent Surveillance-Broadcast (ADS-B) signals. Background Technology

[0002] ADS-B is an aircraft tracking technology in which aircraft periodically broadcast their identification, altitude, speed, and position determined via the Global Positioning System (GPS) protocol. Ground-based air traffic control stations and other aircraft can receive and use the broadcast information to coordinate the flight of many aircraft and help prevent mid-air collisions.

[0003] One drawback of the ADS-B system is that it does not include a protocol for authenticating the received signals. That is, the system presupposes that the aircraft identification and corresponding altitude, position, and speed conveyed by the received signals are accurate. Therefore, there is a degree of uncertainty regarding the content of ADS-B messages. This problem is particularly relevant to unmanned aerial vehicles (UAVs) equipped with ADS-B systems, as there is no pilot on board who can use their own sight or hearing to verify the information included in the received ADS-B signals. Therefore, a system and method for authenticating ADS-B signals are needed. Summary of the Invention

[0004] One aspect of this disclosure is a computing system for evaluating the authenticity of Automatic Dependent Surveillance-Broadcast (ADS-B) signals, the computing system comprising: one or more processors; and a computer-readable medium storing instructions that, when executed by the one or more processors, cause the computing system to perform a function comprising: receiving a first authentication signal, the first authentication signal (i) identifying a first position of a first aircraft relative to a host aircraft where the computing system is located, and (ii) including a first identifier of the first aircraft; subsequently receiving a second signal, the second signal being an ADS-B signal identifying a second position, speed, and aircraft type, wherein the second signal includes a second identifier; based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, using the first position and aircraft type to confirm that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time; and based on confirming that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time, providing an indication that the second signal is authentic.

[0005] Another aspect of this disclosure is a non-transitory computer-readable medium storing instructions that, when executed by a computing system, cause the computing system to perform a function for evaluating the authenticity of an Automatic Dependent Surveillance-Broadcast (ADS-B) signal, the function comprising: receiving a first authentication signal (i) identifying a first position of a first aircraft relative to a host aircraft where the computing system is located, and (ii) including a first identifier of the first aircraft; subsequently receiving a second signal, the second signal being an ADS-B signal identifying a second position, speed, and aircraft type, wherein the second signal includes a second identifier; based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, using the first position and aircraft type to confirm that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time; and based on confirming that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time, providing an indication that the second signal is authentic.

[0006] Another aspect of this disclosure is a method for evaluating the authenticity of an Automatic Dependent Surveillance-Broadcast (ADS-B) signal, the method comprising: receiving by a computing system a first authentication signal, the first authentication signal (i) identifying a first position of a first aircraft relative to a host aircraft where the computing system is located, and (ii) including a first identifier of the first aircraft; receiving, at a subsequent time, a second signal, the second signal being an ADS-B signal identifying a second position, speed, and aircraft type, wherein the second signal includes a second identifier; confirming, based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, using the first position and aircraft type, that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time; and providing an indication that the second signal is authentic based on confirming that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time.

[0007] The terms “about” or “substantially” used with reference to the quantities or measurements described herein mean that the characteristic, parameter, or value does not need to be precisely achieved, but rather that deviations or variations in quantity may occur that do not impede the effect the characteristic is intended to provide, including, for example, tolerances, measurement errors, measurement accuracy limitations, and other factors known to those skilled in the art.

[0008] The features, functions, and advantages discussed can be implemented independently in various examples or combined in other examples, further details of which can be seen in the following description and figures. Attached Figure Description

[0009] The features of the exemplary examples considered to be novel are set forth in the appended claims. However, the exemplary examples, as well as preferred modes of use, further objectives, and their descriptions, will be best understood by referring to the following detailed description of the exemplary examples of this disclosure when read in conjunction with the accompanying drawings.

[0010] Figure 1 This is a schematic diagram of the main aircraft and computing system based on the example.

[0011] Figure 2 This is a schematic diagram illustrating the functions performed by the example aircraft and computing system.

[0012] Figure 3 It is a flowchart based on the example method.

[0013] Figure 4 It is a flowchart based on the example method.

[0014] Figure 5 It is a flowchart based on the example method.

[0015] Figure 6 It is a flowchart based on the example method.

[0016] Figure 7 It is a flowchart based on the example method.

[0017] Figure 8 It is a flowchart based on the example method.

[0018] Figure 9 It is a flowchart based on the example method.

[0019] Figure 10 It is a flowchart based on the example method.

[0020] Figure 11 It is a flowchart based on the example method. Detailed Implementation

[0021] As discussed above, there is a need for systems and methods capable of authenticating ADS-B signals. Therefore, this disclosure includes such systems and methods.

[0022] In this example, the computing system on the host aircraft may receive a first authentication signal at an immediate time. This first authentication signal (i) identifies a first position of the first aircraft relative to the host aircraft and (ii) includes a first identifier of the first aircraft. For example, the first authentication signal may be received via an encrypted communication channel (e.g., other than ADS-B) or may be authenticated by comparing the information conveyed by the first authentication signal with air traffic control information or other verified information. The first authentication signal may include the call sign of the first aircraft (e.g., any alphanumeric identifier), the altitude of the first aircraft, the bearing of the first aircraft relative to the host aircraft, and the distance between the first aircraft and the host aircraft. Any information conveyed by the first authentication signal may be explicit or implicit.

[0023] The computing system may subsequently receive a second signal, which is an ADS-B signal identifying a second position, velocity, and aircraft type. The second signal also includes a second identifier (e.g., any alphanumeric identifier). Any information conveyed by the second signal can be explicit or implicit. The computing system can then match the first and second identifiers to ensure that the second signal corresponds to the first aircraft.

[0024] The computing system can then use the first position indicated by the first authentication signal and the aircraft type indicated by the second signal to confirm that it is possible for the first aircraft to subsequently be at the second position indicated by the second signal and move at the speed indicated by the second signal. For example, the computing system can determine, based on the known performance specifications of the aircraft type (e.g., the specific brand and model of the aircraft), whether it is possible for the first aircraft to be at the first position at the first time it receives the first authentication signal and to subsequently be at the second position and move at the speed indicated by the second signal. In some examples, the computing system can infer the aircraft type of the first aircraft from the first identifier or the second identifier. These performance specifications may include maximum speed, minimum speed, or maximum altitude. The computing system can also determine whether the aforementioned position and speed information is consistent with the known flight plan of the first aircraft. Based on the confirmation that it is possible for the first aircraft to subsequently be at the second position and move at that speed, the computing system can provide (e.g., via a user interface) a true indication of the second signal.

[0025] In some examples, the computing system may additionally receive a third signal, which is an ADS-B signal that explicitly or implicitly identifies a third location, a second velocity, a second aircraft type, and a third identifier. The computing system may identify mismatches between the first and third identifiers, such that the third signal corresponds to a second aircraft (e.g., a new contact). Using the third location, second velocity, and / or second aircraft type, the computing system may confirm that it is possible for the second aircraft to be in the third location and moving at the second velocity at a second time, and provide an indication of this effect (e.g., via a user interface). For example, the computing system may determine that the distance between the primary aircraft and the third location is greater than the standard initial contact distance of the ADS-B signal (e.g., the distance at which the new contact is expected to "appear" via ADS-B tracking).

[0026] The systems and methods disclosed herein may be advantageous because, compared to conventional systems and methods, they can help authenticate ADS-B signals and identify spoofed ADS-B signals.

[0027] Implementations of this disclosure provide technical improvements specific to computer networks and computing systems (e.g., computing systems for authenticating radio transmissions and / or identifying spoofed radio transmissions).

[0028] The technical problems specific to computing systems, such as the management and use of large, complex data streams from multiple sources (e.g., aircraft and air traffic control stations), and the associated inefficiencies, can be fully or partially solved by the implementations of this disclosure. For example, the implementations of this disclosure can reduce the time spent analyzing data to identify genuine and spoofed signals. Therefore, the implementations of this disclosure can reduce the cost and complexity of implementing inefficient methods and systems for diagnosing and resolving these problems. As another example, the implementations of this disclosure increase the accuracy and reliability of diagnostic information.

[0029] The implementation of this disclosure thus introduces new and efficient improvements in how computing systems authenticate radio transmissions, thereby facilitating new and efficient improvements in how associated data is used for diagnosis and problem-solving. The implementation of this disclosure can streamline and perform calculations using large amounts of information that would otherwise be difficult to use for authenticating radio transmissions.

[0030] The disclosed examples will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, of the disclosed examples. In fact, several different examples may be described and should not be construed as limited to the examples set forth herein. Rather, these examples are described so that this disclosure will be thorough and complete and will fully convey the scope of this disclosure to those skilled in the art.

[0031] Figure 1This is a block diagram of the main aircraft 10 including the computing system 100. In some examples, the components of the computing system 100 are distributed across multiple computing systems. However, for illustrative purposes, components are shown and described as part of the computing system 100. The computing system 100 may be or include a mobile device (e.g., a mobile phone), a desktop computer, a laptop computer, a tablet computer, a server, a network of multiple servers, or one or more similar devices that may be configured to perform the functions described herein.

[0032] like Figure 1 As shown, the computing system 100 includes one or more processors 102, a non-transitory computer-readable medium 104, a communication interface 106, a display 108, and a user interface 110. Figure 1 The components of the computing system 100 shown are linked together via a system bus, network, or other connection mechanism 112.

[0033] One or more processors 102 can be any type of processor coupled to non-transitory computer-readable medium 104, such as microprocessors, digital signal processors, multi-core processors, etc.

[0034] The non-transitory computer-readable medium 104 can be any type of memory, such as volatile memory like random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), or non-volatile memory like read-only memory (ROM), flash memory, magnetic disk or optical disk or compact disc read-only memory (CD-ROM), as well as other means for temporarily or permanently storing data or programs.

[0035] Additionally, the non-transitory computer-readable medium 104 may be configured to store instructions 114. Instructions 114 may be executed by one or more processors 102 to cause the computing system 100 to perform any of the functions of the computing system 100 described herein.

[0036] Communication interface 106 may include hardware that allows communication within computing system 100 and / or between computing system 100 and one or more other devices. This hardware may include, for example, a transmitter, a receiver, and an antenna. Communication interface 106 may be configured to facilitate communication with one or more other devices according to one or more wired or wireless communication protocols. For example, communication interface 106 may be configured to facilitate wireless data communication by computing system 100 according to one or more wireless communication standards such as one or more Institute of Electrical and Electronics Engineers (IEEE) 801.11 standards, ZigBee standards, Bluetooth standards, etc. As another example, communication interface 106 may be configured to facilitate wired data communication with one or more other devices.

[0037] Display 108 can be any type of display component configured to display data. As an example, display 108 may include a touchscreen display. As another example, display 108 may include a flat panel display such as a liquid crystal display (LCD) or a light-emitting diode (LED) display.

[0038] User interface 110 may include one or more hardware components for providing data and control signals to computing system 100. For example, user interface 110 may include a mouse or pointing device, a keyboard or keypad, a microphone, a touchpad or touchscreen, and other possible types of user input devices. Typically, user interface 110 enables an operator to interact with a graphical user interface (GUI) provided by computing system 100 (e.g., displayed on display 108).

[0039] Figure 2 Further description of the relationship with Figure 3 Method 300 shown Figure 4 Method 313 shown Figure 5 Method 315 shown Figure 6 Method 317 shown Figure 7 Method 319 shown Figure 8 Method 321 shown Figure 9 Method 327 shown Figure 10 Method 329 shown and Figure 11 The method 331 shown relates to the main aircraft 10, the computing system 100, and the functions.

[0040] like Figure 2 As shown, computing system 100 (e.g., wirelessly from first aircraft 206 at a first time t1) receives a first authentication signal 202, which (i) identifies a first position 204 of first aircraft 206 relative to host aircraft 10 where computing system 100 is located, and (ii) includes a first identifier U1 of first aircraft 206. In other examples, computing system may receive the first authentication signal from air traffic control. The first position 204 is characterized by altitude a1, azimuth θ1 expressed from the host aircraft 10, and distance d1 from the host aircraft 10, but other examples of quantifying the first position are also possible.

[0041] The first authentication signal 202 may be received via an encrypted communication channel (e.g., other than ADS-B), or it may be authenticated by comparing the information conveyed by the first authentication signal 202 with air traffic control information or other verified information. The first identifier U1 may include the call sign of the first aircraft 206 (e.g., any alphanumeric identifier). Any information conveyed by the first authentication signal 202 may be explicit or implicit. In some examples, the first authentication signal 202 is a Traffic Collision Avoidance System (TCAS) signal received from the first aircraft 206. In other examples, the first authentication signal is an Air Traffic Control Voice (ATCV) signal encoded with air traffic control audio, or a Controller Pilot Data Link (CPDL) signal. ATCV and CPDL signals are typically received from air traffic control stations.

[0042] The computing system 100 also receives a second signal 208 at a subsequent time t2 (e.g., wirelessly), which is an ADS-B signal identifying a second position 210, velocity v2, and aircraft type T1. The second signal 208 includes a second identifier U2 (e.g., any alphanumeric identifier). Any information conveyed by the second signal 208 can be explicit or implicit. The second position 210 is characterized by altitude a2, azimuth θ2 from the host aircraft 10, and distance d2 from the host aircraft 10, but other examples of quantifying the second position are also possible. The computing system 100 can then match the first identifier U1 and the second identifier U2 such that the second signal 208 corresponds to the first aircraft 206. That is, the computing system 100 determines that the subsequently received second signal 208 corresponds to the same aircraft as the first authentication signal 202, namely the first aircraft 206.

[0043] Based on matching the first identifier U1 and the second identifier U2 such that the second signal 208 corresponds to the first aircraft 206, the computing system 100 uses the first position 204 and the aircraft type T1 (e.g., the specific brand and model of the aircraft) to confirm that the first aircraft 206 is located at the second position 210 at a speed v2 at a subsequent time t2.

[0044] For example, the computing system 100 can determine, based on the known performance specifications of aircraft type T1, whether it is possible for the first aircraft 206 to be at a first position 204 at a first time t1 after receiving the first authentication signal 202 and then at a second position 210 at a speed v2 indicated by the second signal 208 at a subsequent time t2. In some examples, the computing system 100 can infer the aircraft type T1 of the first aircraft 206 from a first identifier U1 or a second identifier U2 (e.g., via a lookup table). These performance specifications may include maximum speed, minimum speed, or maximum altitude. The computing system 100 can also determine whether the aforementioned position and speed information is consistent with a known flight plan for the first aircraft 206.

[0045] Therefore, in some examples, the first authentication signal is an air traffic control voice (ATCV) signal or a controller pilot data link (CPDL) signal indicating the flight plan of the first aircraft 206 (e.g., received from an air traffic control station). In this case, the computing system 100 can determine that the second position 210 and speed v2 conform to the flight plan (e.g., the second position 210 and speed v2 are within the position and speed limits defined by the flight plan).

[0046] In some examples, the first authentication signal is an ATCV signal. In this case, before determining that the second position 210 and velocity v2 conform to the flight plan, the computing system 100 may perform a speech-to-text conversion of the first authentication signal to determine the flight plan of the first aircraft 206.

[0047] In some examples, it is possible for the calculation system 100 to determine, using a first position 204 and aircraft type T1, that the first aircraft 206 is at a second position 210 at a speed v2 at a subsequent time t2, including determining that the distance 212 between the first position 204 and the second position 210 is less than the maximum distance the first aircraft 206 can travel at the maximum speed of aircraft type T1 between the first time t1 and the subsequent time t2. Before determining that the distance 212 is less than the maximum distance, the calculation system 100 may determine the maximum speed based on aircraft type T1 (e.g., via a lookup table).

[0048] In some examples, it is possible for the calculation system 100 to determine, using the first position 204 and the aircraft type T1, that the first aircraft 206 is at the second position 210 at a speed v2 at a subsequent time t2, including determining that a distance 212 exceeds the minimum distance that the first aircraft 206 can travel at the minimum speed of aircraft type T1 between the first time t1 and the subsequent time t2. Before determining that the distance 212 exceeds the minimum distance, the calculation system 100 may determine the minimum speed based on the aircraft type T1 (e.g., via a lookup table).

[0049] In some examples, it is possible for the calculation system 100 to use the first position 204 and the aircraft type T1 to confirm that the first aircraft 206 is in the second position 210 at a speed v2 at a subsequent time t2, which includes determining that the second position 210 represents a height a2 less than the maximum height of the aircraft type T1. Before determining that the second position 210 represents a height a2 less than the maximum height, the calculation system 100 may determine the maximum height based on the aircraft type T1 (e.g., via a lookup table).

[0050] The computing system 100 may also provide a second signal 208 as an indication that the first aircraft 206 is indeed in the second position 210 at a speed v2 at a subsequent time t2, based on the confirmation that it is possible (e.g., via user interface 110). This is an indication (e.g., displayed text, audio warning, etc.).

[0051] In some examples, the instructions provided by the computing system 100 may be in a less explicit form, such as the computing system 100 controlling or maneuvering the main aircraft 10 based on information included in the second signal 208 (e.g., based on the assumption that the first aircraft 206 is at the second position 210 at a speed v2 at a subsequent time t2). Alternatively or additionally, the instructions provided by the computing system 100 may include a signal sent by the computing system 100 (e.g., to a ground control station) indicating that the second signal 208 is valid. These examples may be particularly relevant when the main aircraft 10 is a UAV.

[0052] In some examples, the computing system 100 may also receive a third signal 214 at a second time t3 after receiving the first authentication signal 202. This third signal 214 is an ADS-B signal identifying a third position 216, a second velocity v3, and a second aircraft type T2. The third signal 214 includes a third identifier U3 (e.g., any alphanumeric value).

[0053] Furthermore, based on the discovery of a mismatch between the first identifier U1 and the third identifier U3, which makes the third signal 214 correspond to a second aircraft 218 different from the first aircraft 206, the computing system 100 can use the third position 216, the second speed v3, or the second aircraft type T2 to confirm that it is possible for the second aircraft 218 to be located at the third position 216 and moving at the second speed v3 at the second time t3. Based on the confirmation that it is possible for the second aircraft 218 to be located at the third position 216 and moving at the second speed v3 at the second time t3, the computing system 100 can also (e.g., via the user interface 110) provide a second indication that the third signal 214 is genuine (e.g., displayed text, audio warning, etc.).

[0054] In some examples, the second instruction provided by the computing system 100 may be in a less explicit form, such as the computing system 100 controlling or manipulating the main aircraft 10 based on information included in the third signal 214 (e.g., based on the assumption that the second aircraft 218 is located at the third position 216 at the second time t3 and moving at the second speed v3). Alternatively or additionally, the second instruction provided by the computing system 100 may include a signal sent by the computing system 100 (e.g., to a ground control station) indicating that the third signal 214 is valid. These examples may be particularly relevant when the main aircraft 10 is a UAV.

[0055] In some examples, it is possible for the calculation system 100 to determine that the second aircraft 218 is at the third position 216 and moving at the second speed v3 at the second time t3 using the third position 216, the second speed v3, or the second aircraft type T2. This includes determining that the third position 216 represents a height a3 less than the maximum height of the second aircraft type T2. Before determining that the third position 216 represents a height a3 less than the maximum height, the calculation system 100 may also determine the maximum height based on the second aircraft type T2 (e.g., via a lookup table).

[0056] In some examples, it is possible for the calculation system 100 to determine, using the third position 216, the second velocity v3, and the second aircraft type T2, that the second aircraft 218 is located at the third position 216 and moving at the second velocity v3 at the second time t3, including determining that the second velocity v3 is less than the maximum velocity of the second aircraft type. Before determining that the second velocity v3 is less than the maximum velocity, the calculation system 100 may determine the maximum velocity based on the second aircraft type T2 (e.g., via a lookup table).

[0057] In some examples, it is possible for the calculation system 100 to determine that the second aircraft 218 is in the third position 216 and moving at the second speed v3 at the second time t3 using the third position 216, the second speed v3, or the second aircraft type T2. This includes determining that the second speed v3 is greater than a minimum speed of the second aircraft type T2. Before determining that the second speed v3 is greater than the minimum speed, the calculation system 100 may determine the minimum speed based on the second aircraft type T2 (e.g., via a lookup table).

[0058] In some examples, confirming that the second aircraft 218 is at the third position 216 and moving at the second speed v3 at the second time t3 using the third position 216, the second speed v3, or the second aircraft type T2 may include: determining that the distance 220 (e.g., d3) between the main aircraft 10 and the third position 216 is greater than the standard initial contact distance of the ADS-B signal. That is, the calculation system 100 determines whether it is reasonable for the first contact received from the second aircraft 218 via the ADS-B system to occur at a distance 220.

[0059] Figures 3 to 11 Flowcharts are shown for methods 300, 313, 315, 317, 319, 321, 327, 329, and 331, implemented according to example methods, for evaluating the authenticity of ADS-B signals. Methods 300, 313, 315, 317, 319, 321, 327, 329, and 331 present methods that can be used with… Figures 1 to 2 An example of a method used with the computing system 100 shown. For example... Figures 3 to 11 As shown, methods 300, 313, 315, 317, 319, 321, 327, 329, and 331 include one or more operations, functions, or actions as shown in blocks 302, 304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326, 328, and 330. Although the blocks are shown sequentially, these blocks may also be executed in parallel and / or in a different order than that described herein. Furthermore, based on desired implementation methods, various blocks may be combined into fewer blocks, divided into additional blocks, and / or removed.

[0060] Reference Figure 3 Block 302 of method 300 includes: receiving a first authentication signal 202 by computing system 100, the first authentication signal 202 (i) identifying a first position 204 of the first aircraft 206 relative to the host aircraft 10 where computing system 100 is located, and (ii) including a first identifier U1 of the first aircraft 206.

[0061] Block 304 of method 300 includes receiving a second signal 208 at a subsequent time t2, the second signal 208 being an ADS-B signal identifying a second position 210, velocity v2, and aircraft type T1. The second signal 208 includes a second identifier U2.

[0062] Block 306 of method 300 includes: based on matching the first identifier U1 and the second identifier U2 such that the second signal 208 corresponds to the first aircraft 206, it is possible to confirm, using the first position 204 and the aircraft type T1, that the first aircraft 206 is located at the second position 210 and moves at a speed v2 at a subsequent time t2.

[0063] Block 308 of method 300 includes: providing a second signal 208 as an indication that it is possible for the first aircraft 206 to move at a speed v2 at a second position 210 at a subsequent time t2 (e.g., via user interface 110).

[0064] Reference Figure 4Block 310 of method 313 includes: performing a speech-to-text conversion of the first authentication signal 202 to determine the flight plan before determining that the second position 210 and velocity v2 conform to the flight plan.

[0065] Block 312 of method 313 includes: determining that the second position 210 and velocity v2 conform to the flight plan.

[0066] Reference Figure 5 Block 314 of method 315 includes: determining the maximum speed based on the aircraft type T1 before determining that the distance 212 is less than the maximum distance.

[0067] Reference Figure 6 Block 316 of method 317 includes: determining a minimum speed based on aircraft type T1 before determining that distance 212 exceeds a minimum distance.

[0068] Reference Figure 7 Block 318 of method 319 includes: determining the maximum altitude based on the aircraft type T1 before determining that the second position 210 represents a height a2 less than the maximum altitude.

[0069] Reference Figure 8 Block 320 of method 321 includes: receiving a third signal 214 at a second time t3 after receiving the first authentication signal 202, the third signal 214 being an ADS-B signal identifying a third position 216, a second velocity v3, and a second aircraft type T2. The third signal 214 includes a third identifier U3.

[0070] Block 322 of method 321 includes: based on the discovery of a mismatch between the first identifier U1 and the third identifier U3, such that the third signal 214 corresponds to the second aircraft 218, confirming that the second aircraft 218 is possible to be in the third position 216 and moving at the second speed v3 at the second time t3 using the third position 216, the second speed v3, or the second aircraft type T2.

[0071] Block 324 of method 321 includes: providing a third signal 214 as a genuine second indication based on the confirmation that the second aircraft 218 is located at the third position 216 at the second time t3 and moving at the second speed v3 (e.g., via user interface 110).

[0072] Reference Figure 9 The block 326 of method 327 includes: determining the maximum altitude based on the second aircraft type T2 before determining that the third position 216 represents a height a3 less than the maximum altitude.

[0073] Reference Figure 10Block 328 of method 329 includes: determining the maximum speed based on the second aircraft type T2 before determining that the second speed v3 is less than the maximum speed.

[0074] Reference Figure 11 Block 330 of method 331 includes: determining the minimum speed based on the second aircraft type T2 before determining that the second speed v3 is greater than the minimum speed.

[0075] It should be understood that, for the same and other processes and methods disclosed herein, the flowcharts illustrate the functionality and operation of one possible implementation of the examples of the invention. Alternative implementations are included within the scope of the examples disclosed herein, wherein functions may not be performed in the order shown or discussed, including, depending on the functions involved, performing substantially simultaneously or in reverse order, as will be understood by those skilled in the art.

[0076] Furthermore, this disclosure includes examples pursuant to the following terms:

[0077] Clause 1. A computing system for evaluating the authenticity of an Automatic Dependent Surveillance-Broadcast (ADS-B) signal, the computing system comprising: one or more processors; and a computer-readable medium storing instructions that, when executed by the one or more processors, cause the computing system to perform a function comprising the steps of: receiving a first authentication signal, the first authentication signal (i) identifying a first position of a first aircraft relative to a host aircraft on which the computing system is located, and (ii) including a first identifier (U1) of the first aircraft; receiving a second signal at a subsequent time (t2), the second signal being an ADS-B signal identifying a second position, a velocity (v2), and an aircraft type (T1), wherein the second signal includes a second identifier (U2); confirming, based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, that it is possible for the first aircraft to be located at the second position and moving at the velocity at the subsequent time; and providing an indication that the second signal is authentic based on confirming that it is possible for the first aircraft to be located at the second position and moving at the velocity at the subsequent time.

[0078] Clause 2. The computing system pursuant to Clause 1, wherein the first authentication signal is a Traffic Collision Avoidance System (TCAS) signal, an Air Traffic Control Voice (ATCV) signal encoded with air traffic control audio, or a Controller Pilot Data Link (CPDL) signal.

[0079] Clause 3. The computing system according to any one of Clauses 1 to 2, wherein the first authentication signal is an air traffic control voice (ATCV) signal or a controller pilot data link (CPDL) signal indicating the flight plan of the first aircraft, and the function further includes: determining that the second position and the speed conform to the flight plan.

[0080] Clause 4. The computing system according to Clause 3, wherein the first authentication signal is an ATCV signal, the function further includes: performing a speech-to-text conversion of the first authentication signal to determine the flight plan before determining that the second position and the speed conform to the flight plan.

[0081] Clause 5. The computing system according to any one of Clauses 1 to 4, wherein receiving a first authentication signal at a first time, and wherein confirming that the first aircraft may be in a second position at the speed at the subsequent time using a first position and an aircraft type comprises: determining that the distance between the first position and the second position is less than the maximum distance that the first aircraft can travel at the maximum speed of the aircraft type between the first time and the subsequent time.

[0082] Clause 6. The calculation system pursuant to Clause 5 further includes the function of determining a maximum speed based on the aircraft type before determining that the distance is less than a maximum distance.

[0083] Clause 7. The computing system according to any one of Clauses 1 to 6, wherein receiving a first authentication signal at a first time, and wherein confirming that it is possible for a first aircraft to be in a second position at the speed at the subsequent time using a first position and an aircraft type, comprises: determining that the distance between the first position and the second position exceeds the minimum distance that the first aircraft can travel at the minimum speed of the aircraft type between the first time and the subsequent time.

[0084] Clause 8. The calculation system pursuant to Clause 7 further includes the function of determining a minimum speed based on the aircraft type before determining that the distance exceeds a minimum distance.

[0085] Clause 9. The calculation system according to any one of Clauses 1 to 8, wherein the step of confirming that it is possible for the first aircraft to be in the second position and moving at the speed at the subsequent time using the first position and aircraft type further includes: determining that the second position represents an altitude less than the maximum altitude of the aircraft type (a2).

[0086] Clause 10. The calculation system pursuant to Clause 9 further includes the function of determining the maximum altitude based on the aircraft type before determining that the second position represents an altitude less than the maximum altitude.

[0087] Clause 11. The computing system according to any one of Clauses 1 to 10, the function further comprising the steps of: receiving a third signal at a second time (t3) after receiving the first authentication signal, the third signal being an ADS-B signal identifying a third position, a second speed (v3), and a second aircraft type (T2), wherein the third signal includes a third identifier; confirming, based on the discovery of a mismatch between the first identifier and the third identifier, such that the third signal corresponds to the second aircraft, that it is possible for the second aircraft to be in the third position and moving at the second speed at the second time; and providing a second indication that the third signal is genuine based on the confirmation that it is possible for the second aircraft to be in the third position and moving at the second speed at the second time.

[0088] Clause 12. The calculation system according to Clause 11, wherein the step of confirming that it is possible for a second aircraft to be in a third position and moving at a second speed at a second time using a third position, a second speed, or a second aircraft type includes: determining that the third position represents an altitude (a3) ​​less than the maximum altitude of the second aircraft type.

[0089] Clause 13. The calculation system pursuant to Clause 12 further includes the function of determining the maximum altitude based on the second aircraft type before determining that the third position represents an altitude less than the maximum altitude.

[0090] Clause 14. The calculation system according to Clause 11, wherein the step of confirming that it is possible for a second aircraft to be in a third position and moving at a second speed at a second time using a third position, a second speed, or a second aircraft type includes: determining that the second speed is less than the maximum speed of the second aircraft type.

[0091] Clause 15. The computing system pursuant to Clause 14 further includes the function of determining the maximum speed based on the second aircraft type before determining that the second speed is less than the maximum speed.

[0092] Clause 16. The calculation system according to Clause 11, wherein the step of confirming that it is possible for a second aircraft to be in a third position and moving at a second speed at a second time using a third position, a second speed, or a second aircraft type includes: determining that the second speed is greater than the minimum speed of the second aircraft type.

[0093] Clause 17. The computing system pursuant to Clause 16 further includes the function of determining a minimum speed based on a second aircraft type before determining that the second speed is greater than the minimum speed.

[0094] Clause 18. The calculation system according to Clause 11, wherein the step of confirming that it is possible for a second aircraft to be in a third position and moving at a second speed at a second time using a third position, a second speed, or a second aircraft type includes: determining that the distance between the primary aircraft and the third position is greater than the standard initial contact distance of the ADS-B signal.

[0095] Clause 19. A non-transitory computer-readable medium storing instructions that, when executed by a computing system, cause the computing system to perform a function for evaluating the authenticity of an Automatic Dependent Surveillance-Broadcast (ADS-B) signal, the function comprising the steps of: receiving a first authentication signal (i) identifying a first position of a first aircraft relative to a host aircraft where the computing system is located, and (ii) including a first identifier (U1) of the first aircraft; receiving a second signal at a subsequent time (t2), the second signal being an ADS-B signal identifying a second position, a velocity (v2), and an aircraft type (T1), wherein the second signal includes a second identifier (U2); confirming, based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, that it is possible for the first aircraft to be located at the second position and moving at the velocity at the subsequent time; and providing an indication that the second signal is authentic based on the confirmation that it is possible for the first aircraft to be located at the second position and moving at the velocity at the subsequent time.

[0096] Clause 20. A method for evaluating the authenticity of an Automatic Dependent Surveillance-Broadcast (ADS-B) signal, the method comprising the steps of: receiving a first authentication signal by a computing system, the first authentication signal (i) identifying a first position of a first aircraft relative to a host aircraft where the computing system is located, and (ii) including a first identifier (U1) of the first aircraft; receiving a second signal at a subsequent time (t2), the second signal being an ADS-B signal identifying a second position, a speed (v2), and an aircraft type (T1), wherein the second signal includes a second identifier (U2); confirming, based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, that it is possible for the first aircraft to be located at the second position and moving at the speed at the subsequent time; and providing an indication that the second signal is authentic based on confirming that it is possible for the first aircraft to be located at the second position and moving at the speed at the subsequent time.

[0097] Various advantageous arrangements have been described for illustrative and descriptive purposes and are not intended to be exhaustive or limited to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different advantageous examples may describe different advantages compared to other advantageous examples. The selected examples have been chosen and described to illustrate the principles of the examples, their practical application, and to enable those skilled in the art to understand the various examples of this disclosure and the various modifications suitable for particular uses that may be conceived.

Claims

1. A computational system (100) for evaluating the authenticity of Automatic Dependent Surveillance-Broadcast (ADS-B) signals, the computational system comprising: One or more processors (102); as well as A computer-readable medium (104) storing instructions (114) that, when executed by the one or more processors, cause the computing system to perform a function comprising the following steps: Receive (302) a first authentication signal (202), which (i) identifies a first position (204) of the first aircraft (206) relative to the host aircraft (10) where the computing system is located, and (ii) includes a first identifier (U1) of the first aircraft; At a subsequent time (t2), a second signal (208) is received (304), which is an ADS-B signal identifying a second position (210), speed (v2) and aircraft type (T1), wherein the second signal includes a second identifier (U2); Based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, it is possible to confirm, using (306) the first position and the aircraft type, that the first aircraft is located at the second position and moving at the said speed at the subsequent time; and Based on the confirmation that it is possible for the first aircraft to be at the second position and moving at the said speed at the subsequent time, (308) the second signal is provided as a true indication. The steps of receiving the first authentication signal at a first time (t1), and of confirming, using (306) the first position and the aircraft type, that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time, include: The function further includes determining (306) that the distance (212) between the first position and the second position is less than the maximum distance that the first aircraft can travel at the maximum speed of the aircraft type between the first time and the subsequent time. Before determining that the distance is less than the maximum distance, the maximum speed is determined (314) based on the type of aircraft.

2. The computing system according to claim 1, wherein, The first authentication signal is a Traffic Collision Avoidance System (TCAS) signal, an Air Traffic Control Voice (ATCV) signal that encodes air traffic control audio, or a Controller Pilot Data Link (CPDL) signal.

3. The computing system according to any one of claims 1 to 2, wherein, The first authentication signal is either an Air Traffic Control Voice (ATCV) signal indicating the flight plan of the first aircraft or a Controller Pilot Data Link (CPDL) signal. The function also includes: Determine (312) that the second position and the speed conform to the flight plan, and Wherein, the first authentication signal is an ATCV signal, and the function further includes: Before determining that the second position and the speed conform to the flight plan, (310) speech-to-text conversion of the first authentication signal is performed to determine the flight plan.

4. The computing system according to any one of claims 1 to 2, wherein, The first authentication signal is received via an encrypted channel.

5. The computing system according to any one of claims 1 to 2, wherein, Receiving the first authentication signal at a first moment, and wherein confirming, using (306) the first position and the aircraft type, that it is possible for the first aircraft to be at the second position and moving at the said speed at the subsequent time, includes the following steps: The function further includes determining (306) that the distance between the first position and the second position exceeds the minimum distance that the first aircraft can travel at the minimum speed of the aircraft type between the first time and the subsequent time. Before determining that the distance exceeds the minimum distance, the minimum speed is determined (316) based on the aircraft type.

6. The computing system according to any one of claims 1 to 2, wherein, The step of confirming, using (306) the first position and the aircraft type, that it is possible for the first aircraft to be at the second position and moving at the speed at the subsequent time further includes: The function further includes determining (306) that the second position represents an altitude (a2) less than the maximum altitude of the aircraft type. Before determining that the second position represents an altitude less than the maximum altitude, the maximum altitude is determined (318) based on the aircraft type.

7. The computing system according to any one of claims 1 to 2, wherein the function further comprises the following steps: At a second time (t3) after receiving the first authentication signal, a third signal (214) is received (320), which is an ADS-B signal identifying a third position (216), a second speed (v3), and a second aircraft type (T2), wherein the third signal includes a third identifier (U3); Based on the discovery of a mismatch between the first identifier and the third identifier, such that the third signal corresponds to the second aircraft (218), it is possible to confirm, using (322) the third position, the second speed, or the second aircraft type, that the second aircraft was moving at the third position and the second speed at the second time; and Based on the confirmation that it is possible for the second aircraft to be located at the third position and moving at the second speed at the second time, the third signal is provided as a genuine second indication.

8. The computing system according to claim 7, wherein, The steps to confirm that it is possible for the second aircraft to be located at the third position and moving at the second speed at the second time using the third position, the second speed, or the second aircraft type (322) include: The function further includes determining (322) that the third position represents an altitude (a3) ​​less than the maximum altitude of the second type of aircraft. Before determining that the third position represents an altitude less than the maximum altitude, the maximum altitude is determined (326) based on the second aircraft type.

9. The computing system according to claim 7, wherein, The steps to confirm that it is possible for the second aircraft to be located at the third position and moving at the second speed at the second time using the third position, the second speed, or the second aircraft type (322) include: The function further includes determining (322) that the second speed is less than the maximum speed of the second type of aircraft. Before determining that the second speed is less than the maximum speed, the maximum speed is determined (328) based on the second aircraft type.

10. The computing system according to claim 7, wherein, The steps to confirm that it is possible for the second aircraft to be located at the third position and moving at the second speed at the second time using the third position, the second speed, or the second aircraft type (322) include: The function further includes determining (322) that the second speed is greater than the minimum speed of the second type of aircraft. Before determining that the second speed is greater than the minimum speed, the minimum speed is determined (330) based on the second aircraft type.

11. The computing system according to claim 7, wherein, The steps to confirm that it is possible for the second aircraft to be located at the third position and moving at the second speed at the second time using the third position, the second speed, or the second aircraft type (322) include: It is determined that the distance (220) between the main aircraft and the third position is greater than the standard initial contact distance of the ADS-B signal.

12. A method (300) for evaluating the authenticity of Automatic Dependent Surveillance-Broadcast (ADS-B) signals, the method comprising the steps of: The computing system (100) receives (302) a first authentication signal (202), which (i) identifies a first position (204) of the first aircraft (206) relative to the host aircraft (10) where the computing system is located, and (ii) includes a first identifier (U1) of the first aircraft; At a subsequent time (t2), a second signal (208) is received (304), which is an ADS-B signal identifying a second position (210), speed (v2) and aircraft type (T1), wherein the second signal includes a second identifier (U2); Based on matching the first identifier and the second identifier such that the second signal corresponds to the first aircraft, it is possible to confirm, using (306) the first position and the aircraft type, that the first aircraft is located at the second position and moving at the said speed at the subsequent time; and Based on the confirmation that it is possible for the first aircraft to be at the second position and moving at the said speed at the subsequent time, (308) the second signal is provided as a true indication. The steps of receiving the first authentication signal at a first time (t1), and of confirming, using (306) the first position and the aircraft type, that it is possible for the first aircraft to be located at the second position and moving at the said speed at the subsequent time, include: The method further includes determining (306) that the distance (212) between the first position and the second position is less than the maximum distance that the first aircraft can travel at the maximum speed of the aircraft type between the first time and the subsequent time. Before determining that the distance is less than the maximum distance, the maximum speed is determined (314) based on the type of aircraft.

13. The method according to claim 12, wherein, The first authentication signal is a Traffic Collision Avoidance System (TCAS) signal, an Air Traffic Control Voice (ATCV) signal that encodes air traffic control audio, or a Controller Pilot Data Link (CPDL) signal.

14. The method according to any one of claims 12 to 13, wherein, The first authentication signal is an air traffic control voice (ATCV) signal indicating the flight plan of the first aircraft or a controller-pilot data link (CPDL) signal, and the method further includes: Determine (312) that the second position and the speed conform to the flight plan, and Wherein, the first authentication signal is an ATCV signal, and the method further includes: Before determining that the second position and the speed conform to the flight plan, (310) speech-to-text conversion of the first authentication signal is performed to determine the flight plan.

15. The method according to any one of claims 12 to 13, wherein, The first authentication signal is received via an encrypted channel.

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