A countermeasure method and system for blackfly unmanned aerial vehicles

Abstract

The application provides a countermeasure method and system for a black flying unmanned aerial vehicle. The method comprises the following steps: detecting remote control link signals of all black flying unmanned aerial vehicles in the vicinity in real time, extracting signal characteristics of each remote control link signal, and constructing a time-frequency countermeasure interval corresponding to each remote control link signal. Since the signal characteristics include a time-frequency range corresponding to the remote control link signal, each time-frequency countermeasure interval strictly matches the time-frequency range of the corresponding remote control link signal and only covers the target remote control link signal area, without expanding the interference range outwardly and generating additional incidental interference, thereby greatly improving the pertinence of the radio frequency interference signal in attacking the remote control link of the black flying unmanned aerial vehicle and effectively suppressing the interference of the radio frequency interference signal on the surrounding legal equipment. Meanwhile, attacking the remote control link of the black flying unmanned aerial vehicle not only greatly improves the countermeasure efficiency on the black flying unmanned aerial vehicle, but also further reduces the interference on the surrounding legal equipment.

Description

Technical Field

[0001] This invention relates to the field of drone countermeasures, and more particularly to a method and system for countering unauthorized drone flights. Background Technology

[0002] Drone countermeasures refer to a comprehensive defense system that uses technological means to detect, identify, track, and neutralize illegal or threatening drones in order to protect airspace security. The core objective of drone countermeasures is to block drone threats while minimizing collateral damage.

[0003] However, existing drone countermeasures typically suffer from one or more of the following problems: low countermeasure accuracy, poor countermeasure efficiency, and easy interference with nearby legitimate wireless devices. Summary of the Invention

[0004] The technical problem solved by this invention is how to achieve efficient and precise countermeasures against unauthorized drones while suppressing interference with surrounding wireless devices.

[0005] To address the aforementioned technical problems, the present invention provides a method for countering unauthorized drone flights, the method comprising: Real-time detection of remote control link signals of all nearby unauthorized drones, and extraction of signal characteristics of each remote control link signal, including the time and frequency range of the corresponding remote control link signal; Based on the signal characteristics of each remote control link signal, a time-frequency countermeasure interval corresponding to each remote control link signal is constructed. Each time-frequency countermeasure interval strictly fits the time-frequency range of the corresponding remote control link signal, covers only the target remote control link signal area, does not expand the interference range outward, and does not generate additional incidental interference. Based on the aforementioned time-frequency countermeasure interval, an interference codebook sequence is formed; The interference codebook sequence is converted into a corresponding radio frequency interference signal; Within the time-frequency countermeasure interval, the radio frequency interference signal is directionally transmitted to the corresponding remote control link signal to counteract the unauthorized drone flight.

[0006] Optionally, before constructing the time-frequency countermeasure intervals corresponding to each remote control link signal, the following steps are also included: Detect the frequency and location of the remote control link signals of all nearby unauthorized drones to determine the physical frequency range; The bandwidth of the baseband interference signal is shifted to the physical frequency range, and the bandwidth of the baseband interference signal is divided into several consecutive equidistant subcarriers according to a fixed frequency interval. Define a total time span, which is divided into several consecutive sub-slots of equal length according to a fixed time interval; A discrete two-dimensional time-frequency network is established based on several consecutive subcarriers and several consecutive subtime slots.

[0007] Optionally, the time-frequency range of the remote control link signal includes the start time and end time of the remote control link signal, as well as the start frequency and end frequency. The method for constructing the time-frequency countermeasure interval corresponding to each remote control link signal based on the signal characteristics of each remote control link signal specifically includes: In a discrete two-dimensional time-frequency network, based on the start time and end time, as well as the start frequency and end frequency of each remote control link signal, the remote control link signal is discretely analyzed to obtain the discrete index of each remote control link signal in the discrete two-dimensional time-frequency network. The discrete index includes the sub-slot index range and the subcarrier index range. Based on the discrete index of each remote control link signal, the time-frequency countermeasure interval of each remote control link signal is obtained.

[0008] Optionally, the method for forming an interference codebook sequence based on the time-frequency countermeasure interval specifically includes: Within the time-frequency countermeasure interval, analyze the frequency distribution type of each sub-time slot; Based on the frequency distribution type of each sub-slot, an interference codebook for the corresponding sub-slot is formed; The interference codebooks corresponding to all sub-slots are integrated to form the interference codebook sequence.

[0009] Optionally, the method for forming the interference codebook for each sub-slot based on the frequency distribution type of each sub-slot specifically includes: If the frequency distribution type of a single sub-slot is a single frequency distribution or a single group of adjacent frequency distributions, then based on the frequency distribution type of a single sub-slot, an interference codebook with a corresponding low peak-to-average power ratio is selected from the pre-stored codebook library. If the frequency distribution type of a single sub-slot is a distribution of multiple adjacent frequency points or multiple non-adjacent frequency points, then based on the frequency distribution type of a single sub-slot, an traversal search optimization is adopted to adjust the phase of each frequency point in a single sub-slot in real time to generate an interference codebook with a corresponding low peak-to-average power ratio.

[0010] Optionally, the time-frequency countermeasure interval is a rectangular area enclosed by the minimum sub-slot index to the maximum sub-slot index and the minimum subcarrier index to the maximum subcarrier index corresponding to the remote control link signal in a discrete two-dimensional time-frequency grid.

[0011] Optionally, the bandwidth of the baseband interference signal satisfies a quantization relationship: Bw = K * Δf, where Bw is the bandwidth of the baseband interference signal, K is the total number of subcarriers, and Δf is the subcarrier spacing; The total time span satisfies the quantitative relationship: Ttotal = M * Ts, where Ttotal is the total time span, M is the total number of sub-slots, and Ts is the duration of a single sub-slot.

[0012] Optionally, the method for converting the interference codebook sequence into a corresponding radio frequency interference signal specifically includes: sequentially performing digital-to-analog conversion, up-conversion modulation, and power amplification on the interference codebook sequence to form the radio frequency interference signal.

[0013] Optionally, when there are multiple unauthorized drones, an independent time-frequency countermeasure interval is constructed for the remote control link signal of each unauthorized drone, and corresponding interference codebook sequences and radio frequency interference signals are generated in parallel based on each time-frequency countermeasure interval to achieve simultaneous countermeasure against multiple unauthorized drones.

[0014] The technical solution of the present invention also provides a countermeasure system for unauthorized drone flights, comprising: The black-flying drone detection equipment is used to detect the remote control link signals of all nearby black-flying drones in real time and extract the signal characteristics of each remote control link signal, including the time and frequency range of the corresponding remote control link signal. Drone countermeasure equipment is used for: Based on the signal characteristics of each remote control link signal, a time-frequency countermeasure interval corresponding to each remote control link signal is constructed, and each time-frequency countermeasure interval only covers the time-frequency range of the corresponding remote control link signal. Based on the aforementioned time-frequency countermeasure interval, an interference codebook sequence is formed; The interference codebook sequence is converted into a corresponding radio frequency interference signal; Within the time-frequency countermeasure interval, the radio frequency interference signal is directionally transmitted to the corresponding remote control link signal to counteract the unauthorized drone flight.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: In the countermeasures method for unauthorized drone flights provided by this invention, the remote control link signals of all nearby unauthorized drone flights are first detected in real time, and the signal characteristics of each remote control link signal are extracted to construct the time-frequency countermeasure interval corresponding to each remote control link signal. Since the signal characteristics include the start and end times, as well as the start and end frequencies of the corresponding remote control link signal, each time-frequency countermeasure interval strictly matches the time-frequency range of the corresponding remote control link signal, covers only the target remote control link signal area, does not expand the interference range outward, and does not generate additional incidental interference. This greatly improves the targeting of radio frequency interference signals against the remote control links of unauthorized drone flights and effectively suppresses the interference of radio frequency interference signals on surrounding legitimate equipment. Furthermore, targeting the remote control links of unauthorized drone flights not only greatly improves the efficiency of countermeasures against unauthorized drone flights but also further reduces interference to surrounding legitimate equipment.

[0016] Furthermore, a discrete two-dimensional time-frequency network is established based on several consecutive subcarriers and several consecutive sub-time slots. Based on the start and end times, as well as the start and end frequencies of each remote control link signal, the signals are discretely analyzed to obtain their discrete indices within the network. This allows for the determination of the time-frequency countermeasure interval for each remote control link signal. Within the time slot and carrier range of the countermeasure interval, the frequency distribution type of each sub-time slot is analyzed, and a corresponding interference codebook is formed based on this type. This significantly suppresses the interference signals obtained from the interference codebooks corresponding to all sub-time slots from affecting wireless devices outside the countermeasure interval. Simultaneously, when the frequency distribution type of a single sub-time slot is a single frequency distribution or a single set of adjacent frequency distributions, it indicates that there is only one unauthorized UAV flying within the controlled area. Therefore, the corresponding interference codebook can be directly selected from the pre-stored codebook library, greatly improving the countermeasure efficiency against unauthorized UAV remote control links. When the frequency distribution of a single sub-time slot is a combination of multiple adjacent frequency points or multiple non-adjacent frequency points, an ergonomic search optimization is employed to adjust the phase of each frequency point within the single sub-time slot in real time, thereby generating the corresponding interference codebook. Since both the interference codebook selected from the pre-stored codebook library and the interference codebook generated through ergonomic search optimization have a low peak-to-average power ratio, signal distortion in the subsequent power amplification stage is avoided, thus greatly improving the stability of the interference signal in countering unauthorized UAVs. Attached Figure Description

[0017] Figure 1 This is the flowchart of the countermeasure method against unauthorized drones provided in this embodiment. Figure 1 ; Figure 2 This is a discrete time-frequency distribution diagram of the q-th remote control link signal in the discrete two-dimensional time-frequency network constructed in this embodiment; Figure 3This is the discrete time-frequency distribution diagram of the time-frequency countermeasure interval of the qth segment of the remote control link signal in the discrete two-dimensional time-frequency network constructed in this embodiment; Figure 4 This is the flowchart of the countermeasure method against unauthorized drones provided in this embodiment. Figure 2 . Detailed Implementation

[0018] As described in the background section, existing drone countermeasures typically suffer from one or more of the following problems: low countermeasure accuracy, poor countermeasure efficiency, and easy interference with nearby legitimate wireless devices.

[0019] The following analysis of existing drone countermeasures will illustrate the problems with these solutions: Currently, common drone countermeasures technologies can be mainly divided into four categories: interference and blocking, deception and control, physical interception and capture, and strike and destruction.

[0020] Interference blocking technology uses high-intensity radio frequency noise to cover the 2.4GHz / 5.8GHz communication bands or GPS or BeiDou navigation bands, thereby achieving electromagnetic suppression and blocking the remote control and navigation links. Due to its low cost and fast response, it is widely used in large-scale security scenarios. However, this technology employs a broad-spectrum interference mode, which can easily damage nearby legitimate wireless devices such as Bluetooth, home WiFi, and civilian communications, and can significantly disrupt the surrounding electromagnetic environment.

[0021] Deceptive control technology induces drones by spoofing GPS coordinates or cracking communication protocols. Although it is highly covert and causes no collateral damage, and can achieve forced landing of drones and intelligence gathering, it has an extremely high technical threshold, relies heavily on vulnerabilities in the target drone's communication protocol, and is costly to develop and use. It is also completely ineffective against drones that use visual or inertial navigation.

[0022] Physical interception and capture methods have a short effective range and a low capture rate for high-speed moving drones, making them difficult to adapt to complex airspace management needs.

[0023] In summary, existing drone countermeasure technologies generally suffer from insufficient accuracy or significant collateral interference, making it difficult to effectively counter unauthorized drones while ensuring the normal operation of legitimate communication equipment in the vicinity. This fails to meet the current practical needs for refined and low-damage airspace security.

[0024] In view of this, the technical solution of the present invention provides a method for countering unauthorized drone flights. First, the remote control link signals of all nearby unauthorized drone flights are detected in real time, and the signal characteristics of each remote control link signal are extracted to construct a time-frequency countermeasure interval corresponding to each remote control link signal. Since the signal characteristics include the start and end times, as well as the start and end frequencies of the corresponding remote control link signal, each time-frequency countermeasure interval strictly matches the time-frequency range of the corresponding remote control link signal, covers only the target remote control link signal area, does not expand the interference range outward, and does not generate additional incidental interference. This greatly improves the targeting effectiveness of radio frequency interference signals against the remote control links of unauthorized drone flights and effectively suppresses interference from radio frequency interference signals to surrounding legitimate equipment. At the same time, targeting the remote control links of unauthorized drone flights not only greatly improves the efficiency of countering unauthorized drone flights but also further reduces interference to surrounding legitimate equipment.

[0025] To make the above-mentioned objectives, features, and beneficial effects of the present invention more apparent and understandable, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a sequence of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. Additionally, directional terms such as above, below, up, down, upward, downward, left, right, etc., are used relative to exemplary embodiments as they are shown in the figures, with upward or upper directions pointing towards the top of the corresponding figure and downward or lower directions pointing towards the bottom of the corresponding figure.

[0027] Please refer to Figure 1 This embodiment provides a method for countering unauthorized drone flights, which includes the following specific steps.

[0028] Step S100: Real-time detection of remote control link signals of all nearby unauthorized drones, and extraction of signal characteristics of each remote control link signal, including the time-frequency range of the corresponding remote control link signal.

[0029] The countermeasure method for unauthorized drone flights proposed in this application innovatively selects to precisely counter the remote control link signal of the unauthorized drone, rather than using traditional image transmission signal interference. This selection has significant technical advantages: First, the remote control link, as the control nerve center of the UAV, usually has a much narrower signal bandwidth than the image transmission link. Furthermore, by performing time-frequency discretization processing on the remote control link signal, the amount of interference calculation can be greatly simplified and the response speed can be improved.

[0030] Secondly, precise strikes to the remote control link can achieve a "one-hit kill". Once the remote control command link is cut off, the drone will trigger the loss of control protection mechanism and directly make an emergency landing or return to home.

[0031] In this embodiment, the time-frequency range of the remote control link signal includes the start time and end time of the remote control link signal, as well as the start frequency and end frequency of the remote control link signal.

[0032] Step S200: Based on the signal characteristics of each remote control link signal, construct the time-frequency countermeasure interval corresponding to each remote control link signal.

[0033] The following will describe in detail the specific steps for constructing the time-frequency countermeasure interval of the remote control link signal in this embodiment: Step S201: Detect the frequency location of the remote control link signals of all surrounding unauthorized drones to determine the physical frequency range.

[0034] The preferred physical frequency range for the remote control link of civilian consumer-grade unauthorized drones is 2.400GHz to 2.4835GHz, as this band is a globally universal ISM open band that can cover the remote control signals of most consumer-grade drones on the market. For high-end long-range drones, the physical frequency range can be extended to 5.725GHz to 5.850GHz. Both bands can be used independently or simultaneously to meet the countermeasures needs of all types of unauthorized drones. Therefore, in this embodiment, the physical frequency range can be set to 2.400GHz to 2.4835GHz. Of course, 5.725GHz to 5.850GHz can also be selected as needed; this is not limited here.

[0035] Step S202: The bandwidth of the baseband interference signal is shifted to the physical frequency range, and the bandwidth of the baseband interference signal is divided into several consecutive equidistant subcarriers according to a fixed frequency interval.

[0036] In this embodiment, the bandwidth of the baseband interference signal specifically refers to the signal protocol bandwidth of the remote control link signal of the unauthorized UAV. Shifting the bandwidth of the baseband interference signal to the physical frequency range ensures that the bandwidth of the baseband interference signal does not exceed the physical frequency range.

[0037] In this embodiment, the bandwidth of the baseband interference signal satisfies the quantization relationship: Bw = K * Δf, where Bw is the bandwidth of the baseband interference signal, K is the total number of subcarriers, and Δf is the subcarrier spacing.

[0038] Step S203: Define the total time span, which is divided into several consecutive sub-slots of equal length according to a fixed time interval.

[0039] In this embodiment, the total time span satisfies a quantification relationship: Ttotal = M * Ts, where Ttotal is the total time span, M is the total number of sub-slots, and Ts is the duration of a single sub-slot.

[0040] Step S204: Establish a discrete two-dimensional time-frequency network based on several consecutive subcarriers and several consecutive subtime slots.

[0041] In this embodiment, This represents the sub-time-frequency grid cell in the (k+1)th row and (m+1)th column of a discrete two-dimensional time-frequency network. The corresponding time center is Tm, and the frequency center is Xk. The formulas for Tm and Xk are as follows: Where k represents the index of each subcarrier, 0≤k≤K-1; m represents the index of each subslot, 0≤m≤M-1.

[0042] Step S205: In the discrete two-dimensional time-frequency network, based on the start time and end time, as well as the start frequency and end frequency of each remote control link signal, the remote control link signal is discretely analyzed to obtain the discrete index of each remote control link signal in the discrete two-dimensional time-frequency network.

[0043] In this embodiment, the discrete index includes a sub-slot index range and a subcarrier index range. The sub-slot index range includes the start sub-slot and end sub-slot of the remote control link signal, and the subcarrier index range includes the start subcarrier and end subcarrier of the remote control link signal.

[0044] Step S206: Based on the discrete index of each remote control link signal, obtain the time-frequency countermeasure interval of each remote control link signal.

[0045] Suppose there exists a Q-segment remote control link signal for a black-flying UAV in a discrete two-dimensional time-frequency network. Taking the q-th segment of the remote control link signal as an example, where 1≤q≤Q.

[0046] Please refer to Figure 2 and Figure 3 It should be noted that, in practical applications, the start and end times of the q-th remote control link signal in the discrete two-dimensional time-frequency network will not be exactly at the intersection of the two subcarriers, and the start and end frequencies of the q-th remote control link signal will not be exactly at the intersection of the two sub-time slots.

[0047] Therefore, after obtaining the discrete index of the q-th remote control link signal, the sub-slot index range of the q-th remote control link signal in the discrete two-dimensional time-frequency network is dynamically adjusted to ensure that the countermeasure interval completely covers the start and end sub-slots of the q-th remote control link signal. Similarly, the subcarrier index range of the q-th remote control link signal in the discrete two-dimensional time-frequency network is dynamically adjusted to ensure that the countermeasure interval completely covers the start and end subcarriers of the q-th remote control link signal. For example, when the start time of the q-th remote control link signal is a random time within the first sub-slot, the start slot index of the time-frequency countermeasure interval of the q-th remote control link signal is adjusted to the start time of the first sub-slot. When the start frequency of the q-th remote control link signal is a random frequency within the third subcarrier, the start carrier index of the time-frequency countermeasure interval of the q-th remote control link signal is adjusted to the start frequency of the third subcarrier. Of course, the adjustment method for the cutoff time slot index and cutoff carrier index of the time-frequency countermeasure interval of the q-th remote control link signal is the same as above, so that the time-frequency countermeasure interval of the q-th remote control link signal completely covers the start time and cutoff time of the q-th remote control link signal, as well as the start frequency and cutoff frequency of the q-th remote control link signal.

[0048] In this embodiment, the discrete index of the time-frequency countermeasure interval of the q-th segment of the remote control link signal is as follows: in, The starting time slot index used to characterize the q-th segment of the remote control link signal; The cutoff time slot index used to characterize the q-th segment of the remote control link signal; The starting carrier index used to characterize the q-th segment of the remote control link signal; The cutoff carrier index used to characterize the q-th segment of the remote control link signal; Used to characterize the start time of the q-th segment of the remote control link signal; Used to characterize the cutoff time of the q-th segment of the remote control link signal; Used to characterize the starting frequency of the q-th segment of the remote control link signal; Used to characterize the cutoff frequency of the q-th segment of the remote control link signal.

[0049] The construction of the time-frequency countermeasure interval for the remaining remote control link signals is similar to that of the q-th segment of the remote control link signal, and will not be described in detail here.

[0050] Because each time-frequency countermeasure interval strictly matches the time-frequency range of the corresponding remote control link signal, it achieves extremely low collateral interference effect, and only transmits interference within a micro-hour space-time range where the target remote control link signal exists, which not only ensures the countermeasure effect, but also protects the surrounding electromagnetic environment to the greatest extent.

[0051] Step S300: Based on the time-frequency countermeasure interval, form an interference codebook sequence.

[0052] Please refer to Figure 4 In this embodiment, forming the interference codebook sequence based on the time-frequency countermeasure interval specifically includes the following steps: Step S301: Within the time-frequency countermeasure interval, analyze the frequency distribution type of each sub-time slot.

[0053] Step S302: Determine whether the frequency distribution type of a single sub-time slot is a single frequency distribution or a single group of adjacent frequency distributions. If the frequency distribution type of a single sub-time slot is a single frequency distribution or a single group of adjacent frequency distributions, proceed to step S303. If the frequency distribution type of a single sub-time slot is not a single frequency distribution or a single group of adjacent frequency distributions, proceed to step S304.

[0054] Step S303: Based on the frequency distribution type of a single sub-slot, select an interference codebook with a corresponding low peak-to-average power ratio from the pre-stored codebook library.

[0055] Because the remote control link signal bandwidth of civilian unauthorized drones is rigidly defined by the communication protocol and cannot be arbitrarily changed (e.g., WiFi 802.11b / g / n or DJI OcuSync), the frequency pattern of a single drone's remote control link signal in a single sub-time slot typically includes only a single frequency point or a single group of adjacent frequency points. Furthermore, since the number of combinations of single frequency points or single group of adjacent frequency points is limited, a corresponding pre-stored codebook library can be pre-built. When it is determined that the frequency distribution of a single sub-time slot matches a pre-stored codebook in the library, the corresponding pre-stored codebook can be directly retrieved. This eliminates the computational computation stage, compressing the countermeasure response time to the millisecond level and preventing unauthorized drones from escaping control due to computational delays.

[0056] Furthermore, when constructing the pre-stored codebook library, peak-to-average power ratio (PAPR) and power optimization can be performed on each pre-stored codebook within the library. Therefore, during actual countermeasures, there is no need to perform phase adjustment and PAPR optimization again, allowing the direct generation of interference codebooks with low PAPR and meeting power requirements. This avoids overload and distortion issues in the subsequent power amplifiers caused by codebook parameter fluctuations due to real-time calculations, thereby improving the stability of the UAV countermeasure equipment in the system.

[0057] In this embodiment, the method for establishing the pre-stored codebook library includes the following steps: Step 1: Determine the coverage of the pre-stored codebook and match it with the drone protocol specification.

[0058] Specifically, this includes: determining the frequency structure types that the pre-stored codebook needs to cover, based on the mainstream bandwidth of the civilian drone remote control link.

[0059] Frequency point structure types can include: single frequency point – corresponding to one subcarrier, two consecutive subcarriers, three consecutive subcarriers, four consecutive subcarriers, and five consecutive subcarriers. This can adapt to the remote control signal bandwidth of all consumer drones on the market, without unlimited expansion, reducing storage resource consumption.

[0060] Step 2: Generate the fundamental frequency signal offline based on the parameters of the discrete two-dimensional time-frequency network.

[0061] Specifically, this includes: using the parameters of the discrete two-dimensional time-frequency network in this embodiment as a reference, generating a corresponding subcarrier index frequency domain signal for each frequency point structure type set in step 1.

[0062] For example, for "3 consecutive subcarriers", the generated subcarrier index frequency domain signals are k, k+1 and k+2 arranged in sequence to correspond to the 3 consecutive subcarriers, and k depends on the subcarrier index of the first subcarrier among the 3 consecutive subcarriers.

[0063] Step 3: Optimize the peak-to-average power ratio of the subcarrier index frequency domain signal offline and generate the optimal codebook.

[0064] Specifically, this includes: for each type of frequency point structure subcarrier index frequency domain signal, by iterating and adjusting the phase of each frequency point signal, calculating the peak-to-average power ratio of the synthesized signal under different phase combinations, selecting the phase combination with the smallest peak-to-average power ratio and an average power greater than or equal to the countermeasure threshold, and assigning this phase combination to the corresponding subcarrier index frequency domain signal, thereby generating the corresponding digital baseband codebook sequence, i.e. the corresponding interference codebook.

[0065] Step 4: Classify, number, and mark the features of the interference codebooks to establish retrieval rules.

[0066] Specifically, this includes: classifying and storing the optimized interference codebook according to frequency point structure type, and assigning a unique retrieval identifier to each type of frequency point structure, for example, single frequency point = 001, two consecutive subcarriers = 002, three consecutive subcarriers = 003, and marking core features such as the number of matching subcarriers, the low peak-to-average power ratio, and the minimum countermeasure power in the codebook, so as to establish a fast matching rule of "frequency point structure type → retrieval identifier → corresponding codebook", ensuring that in actual countermeasures, the system can directly retrieve the codebook through the retrieval identifier after identifying the frequency point structure.

[0067] Step 5: Verify and update the codebase to ensure compatibility.

[0068] Specifically, this includes: conducting full-scenario offline verification of the pre-stored codebook library, converting various codebooks into radio frequency signals, simulating the suppression effect on the remote control links of different drone models, and verifying the suppression effectiveness and low peak-to-average power ratio optimization characteristics of the codebooks. Simultaneously, an online update interface for the codebook library is reserved. If new protocols for drones emerge later (new bandwidth / new number of subcarriers), new codebooks can be generated offline and then remotely updated to the pre-stored codebook library, ensuring the long-term adaptability of the codebook library.

[0069] Step S304: Based on the frequency distribution type of a single sub-slot, an ergonomic search optimization is used to generate an interference codebook with a corresponding low peak-to-average power ratio.

[0070] Since the frequency distribution of a single sub-time slot is either a combination of multiple adjacent frequency points or multiple non-adjacent frequency points, it indicates that multiple unauthorized drones are flying simultaneously. In this scenario, there is not only an infinite number of frequency combinations for a single sub-time slot, but also the risk of peak-to-average power ratio running out of control due to the superposition of multiple frequency points. In order to balance the storage resources, computing power allocation, and countermeasure accuracy of the countermeasure system, it is necessary to use traversal search optimization to generate the interference codebook corresponding to a single sub-time slot in real time.

[0071] The method for traversing and searching to optimize the generation of interference codebooks includes the following specific steps: Step 1: Locate the target frequency set and define the phase adjustment boundary.

[0072] Based on the subcarrier index set (such as k1~k2, k4~k5) parsed from the time-frequency countermeasure interval, the target frequency range for this traversal search is determined. Phase adjustment is only performed on the frequency points within the countermeasure interval, without involving any subcarriers outside the interval. At the same time, the basic parameters of each target frequency point are extracted: frequency point power (preset according to the countermeasure threshold, fixed at P0) and frequency point interval (consistent with the subcarrier interval Δf) to ensure that the adjusted frequency points still match the time-frequency grid rules.

[0073] Step 2: Set the phase adjustment rules and traversal step size.

[0074] 1. Adjustable phase range: limited to 0°~360° (0~2π), covering the full phase range of sinusoidal signals, ensuring the integrity of phase adjustment.

[0075] 2. Phase traversal step size: preferably 15°, 30° or 45° (can be dynamically adjusted according to the computing power of the device). The smaller the step size, the higher the search accuracy, but the computing time will increase slightly. Conversely, the accuracy will decrease slightly and the time will be greatly reduced (30° is preferred for civilian countermeasures equipment, which balances accuracy and real-time performance, and the number of traversal combinations is controllable).

[0076] 3. Adjustment independence: The phase of each target frequency point can be adjusted independently without interference. The phase value of each frequency point can be taken in steps within the range of 0°~360°.

[0077] Step 3: Define the objective function and constraints of the traversal search.

[0078] To avoid meaningless searches, ensure the effectiveness of the generated codebook in countermeasures, and leverage the low peak-to-average power ratio, a clear mathematical objective function and hard constraints are defined. All traversal results must satisfy the constraints before the optimal solution is selected according to the objective function.

[0079] Step 4: Perform a full phase traversal and calculate the peak-to-average power ratio for each combination.

[0080] Based on the target frequency point in step 1 and the phase rule in step 2, all possible phase combinations are generated through exhaustive search. For each phase combination, the following operations are performed: 1. Assign corresponding phase values ​​to each target frequency point to generate a single-frequency digital baseband signal Sk(t)=A·cos(2πfkt+φk) (A is the signal amplitude, fk is the physical frequency of the frequency point, and φk is the traversal phase value).

[0081] 2. By superimposing all single-frequency signals in the time domain, the target set of the synthetic interference signal corresponding to the phase combination is obtained.

[0082] 3. Calculate the peak value and mean value of the synthesized signal, and then obtain the peak-to-average power value of the combination.

[0083] 4. Repeat the above operation for all phase combinations to form a three-dimensional dataset of phase combination - peak-average power value - average power, while removing combinations whose average power does not meet the constraints.

[0084] Step 5: Select the optimal phase combination and generate the basic interference codebook.

[0085] From the effective dataset, the phase combinations with the smallest peak-to-average power ratio are sorted in ascending order and selected as the optimal phase configuration. This configuration is then assigned to each target frequency point to generate the corresponding digital baseband signal sequence, which is the jamming codebook. The frequency distribution and power of this jamming codebook are completely matched with the target countermeasure interval.

[0086] Step 6: Codebook adaptation and verification, output the final executable codebook.

[0087] Time-frequency grid adaptation verification is performed on the basic codebook: ① Time dimension: The duration of the codebook is completely consistent with the duration Ts of a single sub-slot, ensuring transmission within the corresponding sub-slot; ② Frequency dimension: The frequency index of the codebook is without deviation from the subcarrier index of the countermeasure interval; ③ Hardware adaptation: The amplitude range of the verification codebook matches the input range of the digital-to-analog converter module to avoid signal clipping distortion; After the verification is passed, the final low peak-to-average power value is output to interfere with the codebook for subsequent RF signal conversion.

[0088] It should be noted that when the frequency distribution of a single sub-slot is a combination of multiple adjacent frequency distributions or multiple non-adjacent frequency distributions, in addition to using traversal search optimization, some countermeasure frequencies can be pre-assumed, and corresponding codebook sequences can be trained based on these assumptions to meet actual countermeasure requirements. Specific training methods can be found in the section on establishing the pre-stored codebook library, and will not be elaborated upon here.

[0089] Step S305: Integrate the interference codebooks corresponding to all sub-slots to form the interference codebook sequence.

[0090] It should be noted that when there are multiple unauthorized drones, an independent time-frequency countermeasure interval is constructed for the remote control link signal of each unauthorized drone, and corresponding interference codebook sequences and radio frequency interference signals are generated in parallel based on each time-frequency countermeasure interval to achieve simultaneous countermeasure against multiple unauthorized drones.

[0091] The above is the complete content of step S300. The remaining steps of the countermeasures against unauthorized drone flights are explained below: Step S400: Convert the interference codebook sequence into a corresponding radio frequency interference signal. In this embodiment, the method for converting the interference codebook sequence into a corresponding radio frequency interference signal specifically includes: performing digital-to-analog conversion, up-conversion modulation, and power amplification on the interference codebook sequence in sequence to form a high-power radio frequency interference signal.

[0092] Step S500: Within the time-frequency countermeasure interval, the radio frequency interference signal is directionally transmitted to the corresponding remote control link signal to counter the unauthorized drone.

[0093] Since the radio frequency interference signal is only within the time-frequency countermeasure interval corresponding to the illegal drone, and the time-frequency countermeasure interval perfectly covers the time-frequency range of the remote control link signal of the illegal drone, it can accurately suppress the illegal drone without affecting the surrounding communication equipment.

[0094] This embodiment also provides a countermeasure system for unauthorized drone flights, including unauthorized drone detection equipment and drone countermeasure equipment.

[0095] The black-flying drone detection equipment is used to detect the remote control link signals of all nearby black-flying drones in real time and extract the signal characteristics of each remote control link signal, including the time and frequency range of the corresponding remote control link signal.

[0096] Specifically, the time-frequency range of the remote control link signal includes the start time and end time of the remote control link signal, as well as the start frequency and end frequency.

[0097] The UAV countermeasure device constructs a time-frequency countermeasure interval corresponding to each remote control link signal based on the signal characteristics of each remote control link signal. Each time-frequency countermeasure interval only covers the time-frequency range of the corresponding remote control link signal.

[0098] The drone countermeasure device also forms an interference codebook sequence based on the time-frequency countermeasure interval.

[0099] The drone countermeasure device also converts the jamming codebook sequence into a corresponding radio frequency jamming signal.

[0100] The drone countermeasure device also directionally transmits the radio frequency interference signal to the corresponding remote control link signal within the time-frequency countermeasure interval in order to counter the unauthorized drone flight.

[0101] Since the specific implementation methods and corresponding beneficial effects of the above-mentioned functions of the anti-drone device have been described in detail in the anti-black flying drone method provided in this embodiment, they will not be repeated here.

[0102] In summary, the countermeasure method and system for illegal drones provided in this embodiment not only greatly improves the targeting of radio frequency interference signals against the remote control links of illegal drones and effectively suppresses the interference of radio frequency interference signals on surrounding legitimate devices, but also targets the remote control links of illegal drones, greatly improving the countermeasure efficiency against illegal drones and further reducing interference to surrounding legitimate devices.

[0103] Furthermore, by judging the frequency distribution type of a single sub-time slot and adopting the corresponding interference codebook generation strategy based on the judgment result, and the generated interference codebooks are all low peak-to-average power ratio, it can not only improve the countermeasure efficiency of the remote control link of the black-flying drone, but also avoid signal distortion in the subsequent power amplification stage, thereby greatly improving the stability of the interference signal countermeasure against the black-flying drone.

[0104] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for countering unauthorized drone flights, characterized in that, The method includes: Real-time detection of remote control link signals of all nearby unauthorized drones, and extraction of signal characteristics of each remote control link signal, including the time and frequency range of the corresponding remote control link signal; Based on the signal characteristics of each remote control link signal, a time-frequency countermeasure interval corresponding to each remote control link signal is constructed. Each time-frequency countermeasure interval strictly fits the time-frequency range of the corresponding remote control link signal, covers only the target remote control link signal area, does not expand the interference range outward, and does not generate additional incidental interference. Based on the aforementioned time-frequency countermeasure interval, an interference codebook sequence is formed; The interference codebook sequence is converted into a corresponding radio frequency interference signal; Within the time-frequency countermeasure interval, the radio frequency interference signal is directionally transmitted to the corresponding remote control link signal to counteract the unauthorized drone flight.

2. The method for countering unauthorized drone flights according to claim 1, characterized in that, Before constructing the time-frequency countermeasure intervals corresponding to each remote control link signal, the following steps are also included: Detect the frequency and location of the remote control link signals of all nearby unauthorized drones to determine the physical frequency range; The bandwidth of the baseband interference signal is shifted to the physical frequency range, and the bandwidth of the baseband interference signal is divided into several consecutive equidistant subcarriers according to a fixed frequency interval. Define a total time span, which is divided into several consecutive sub-slots of equal length according to a fixed time interval; A discrete two-dimensional time-frequency network is established based on several consecutive subcarriers and several consecutive subtime slots.

3. The method for countering unauthorized drone flights according to claim 2, characterized in that, The time-frequency range of the remote control link signal includes the start time and end time of the remote control link signal, as well as the start frequency and end frequency. The method for constructing the time-frequency countermeasure interval corresponding to each remote control link signal based on the signal characteristics of each remote control link signal specifically includes: In a discrete two-dimensional time-frequency network, based on the start time and end time, as well as the start frequency and end frequency of each remote control link signal, the remote control link signal is discretely analyzed to obtain the discrete index of each remote control link signal in the discrete two-dimensional time-frequency network. The discrete index includes the sub-slot index range and the subcarrier index range. Based on the discrete index of each remote control link signal, the time-frequency countermeasure interval of each remote control link signal is obtained.

4. The method for countering unauthorized drone flights according to claim 3, characterized in that, The method for forming an interference codebook sequence based on the aforementioned time-frequency countermeasure interval specifically includes: Within the time-frequency countermeasure interval, analyze the frequency distribution type of each sub-time slot; Based on the frequency distribution type of each sub-slot, an interference codebook for the corresponding sub-slot is formed; The interference codebooks corresponding to all sub-slots are integrated to form the interference codebook sequence.

5. The method for countering unauthorized drone flights according to claim 4, characterized in that, The method for forming the interference codebook for each sub-slot based on the frequency distribution type of each sub-slot specifically includes: If the frequency distribution type of a single sub-slot is a single frequency distribution or a single group of adjacent frequency distributions, then based on the frequency distribution type of a single sub-slot, an interference codebook with a corresponding low peak-to-average power ratio is selected from the pre-stored codebook library. If the frequency distribution type of a single sub-slot is a distribution of multiple adjacent frequency points or multiple non-adjacent frequency points, then based on the frequency distribution type of a single sub-slot, an traversal search optimization is adopted to adjust the phase of each frequency point in a single sub-slot in real time to generate an interference codebook with a corresponding low peak-to-average power ratio.

6. The method for countering unauthorized drone flights according to claim 3, characterized in that, The time-frequency countermeasure interval is a rectangular area enclosed by the minimum sub-time slot index to the maximum sub-time slot index and the minimum subcarrier index to the maximum subcarrier index corresponding to the remote control link signal in a discrete two-dimensional time-frequency grid.

7. The method for countering unauthorized drone flights according to claim 2, characterized in that, The bandwidth of the baseband interference signal satisfies the quantization relationship: Bw = K * Δf, where Bw is the bandwidth of the baseband interference signal, K is the total number of subcarriers, and Δf is the subcarrier spacing; The total time span satisfies the quantitative relationship: Ttotal = M * Ts, where Ttotal is the total time span, M is the total number of sub-slots, and Ts is the duration of a single sub-slot.

8. The method for countering unauthorized drone flights according to claim 1, characterized in that, The method for converting the interference codebook sequence into a corresponding radio frequency interference signal specifically includes: performing digital-to-analog conversion, up-conversion modulation, and power amplification on the interference codebook sequence in sequence to form the radio frequency interference signal.

9. The method for countering unauthorized drone flights according to claim 1, characterized in that, When multiple unauthorized drones are present, an independent time-frequency countermeasure interval is constructed for the remote control link signal of each unauthorized drone, and corresponding interference codebook sequences and radio frequency interference signals are generated in parallel based on each time-frequency countermeasure interval to achieve simultaneous countermeasure against multiple unauthorized drones.

10. A countermeasure system for unauthorized unmanned aerial vehicles (UAVs) flying illegally, characterized in that: include: The black-flying drone detection equipment is used to detect the remote control link signals of all nearby black-flying drones in real time and extract the signal characteristics of each remote control link signal, including the time and frequency range of the corresponding remote control link signal. Drone countermeasure equipment is used for: Based on the signal characteristics of each remote control link signal, a time-frequency countermeasure interval corresponding to each remote control link signal is constructed, and each time-frequency countermeasure interval only covers the time-frequency range of the corresponding remote control link signal. Based on the aforementioned time-frequency countermeasure interval, an interference codebook sequence is formed; The interference codebook sequence is converted into a corresponding radio frequency interference signal; Within the time-frequency countermeasure interval, the radio frequency interference signal is directionally transmitted to the corresponding remote control link signal to counteract the unauthorized drone flight.

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