Radio detection method and system for low, slow and small unmanned aerial vehicles

Abstract

The application discloses a radio detection method and system for low, slow and small unmanned aerial vehicles, and relates to the technical field of unmanned aerial vehicles.The technical solution points are as follows: a signal processing board controls the working of corresponding antenna units in an antenna array by controlling a switch matrix of a corresponding channel during detection; a down-conversion channel and an analog-to-digital conversion module of a radio frequency transceiver process the data of a suspicious target to obtain a digital signal; the signal processing board performs amplitude comparison direction finding, single-pulse angle measurement and spectrum recognition processing on the digital signal to obtain the horizontal direction, frequency, amplitude and modulation mode information of the suspicious target; a two-dimensional turntable performs pitching rotation according to the horizontal direction and judges the pitching angle of the unmanned aerial vehicle according to the signal power amplitude; and the signal processing board reports all data of the suspicious target to a command control center for graphic display.The application detects the horizontal angle, pitching angle, approximate distance, spectrum information and other information of the unmanned aerial vehicle within a certain range by using a single terminal.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and more specifically, to a radio detection method and system for low-speed, small UAVs. Background Technology

[0002] With the development of low-altitude air traffic, the number of low-altitude aircraft is increasing, and the air situation at low altitudes is becoming more complex. This makes it increasingly difficult to monitor, control, command, and manage low-altitude airspace, as well as to ensure low-altitude air defense. Relying on only one or two methods is insufficient to solve the problem of controlling and monitoring low-altitude airspace. Therefore, researching and utilizing multi-mode target tracking technology to achieve accurate orientation of UAV aircraft and spectrum data identification and analysis is particularly important.

[0003] Most existing radio detection methods for unmanned aerial vehicles (UAVs) can only detect the horizontal azimuth angle of the UAV, but cannot detect the pitch angle. Solutions that can detect both azimuth and pitch angles simultaneously are either multi-terminal joint detection or a combination of large functional units. Currently, there is no technology that can achieve dual-angle detection and spectrum data identification with a single terminal, while also having low power consumption, small size, and easy setup.

[0004] Therefore, how to research and design a radio detection method and system for low, slow, and small unmanned aerial vehicles that can overcome the above-mentioned defects is an urgent problem that we need to solve. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a radio detection method and system for low-speed, small unmanned aerial vehicles (UAVs). This system can detect information such as the horizontal angle, pitch angle, approximate distance, and spectrum information of UAVs within a certain range using a single terminal. The background software supports functions such as graphic display, alarm reminders, blacklist / whitelist settings, trajectory playback, and storage export. At the same time, power consumption, size, and weight are controlled, and the system is easy to set up.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] The first aspect provides a radio detection method for low-speed, small unmanned aerial vehicles (UAVs), including the following steps:

[0008] After the device completes its power-on self-test, it enters detection mode to detect spatial radio waves within a 360° omnidirectional coverage area around the device in real time.

[0009] During detection, the signal processing board controls the corresponding antenna elements in the antenna array by controlling the switching matrix of the corresponding channel;

[0010] The downconversion path and analog-to-digital conversion module of the radio frequency transceiver process the data of the suspected target to obtain a digital signal;

[0011] The signal processing board performs amplitude comparison, direction finding, single-pulse angle finding, and spectrum identification on the digital signal to obtain information on the horizontal direction, frequency, amplitude, and modulation mode of the suspicious target.

[0012] The two-dimensional turntable rotates in the horizontal direction and determines the pitch angle of the UAV based on the signal power amplitude.

[0013] The signal processing board reports all data of the suspected target to the command and control center for graphical display.

[0014] Furthermore, the process of obtaining the horizontal direction of the suspected target is as follows:

[0015] The preliminary horizontal angle range of the suspected target was determined using an amplitude comparison direction finding algorithm;

[0016] A single-pulse angle measurement algorithm is used to calculate the precise horizontal angle of the suspicious target within the initial direction range, so as to locate the horizontal direction of the suspicious target.

[0017] Furthermore, the process of determining the preliminary horizontal angle range is as follows:

[0018] The preliminary horizontal angle of the suspected target was calculated using the amplitude comparison direction finding algorithm;

[0019] The initial horizontal angle is adjusted by adjusting the fluctuation based on the equipment error value to obtain the initial horizontal angle range.

[0020] Furthermore, the specific formula for calculating the preliminary horizontal angle is as follows:

[0021]

[0022] in, θ represents the initial horizontal angle characterized by the angle of the incident signal. r θ represents the half-power beamwidth of the pattern function. s The angle between adjacent antennas is represented by R; R represents the logarithmic voltage ratio, measured in decibels.

[0023] Furthermore, the calculation process for the precise horizontal angle is as follows:

[0024] Establish a monotonically changing angle measurement curve;

[0025] The difference and ratio between the two channels are calculated using a single-pulse angle measurement algorithm;

[0026] The deflection angle of the target object is selected from the angle measurement curve based on the difference and ratio as the precise horizontal angle.

[0027] Furthermore, the specific formula for calculating the difference and ratio between the two channels is as follows:

[0028]

[0029] E Σ =b1+b2

[0030] E Δ =b1-b2

[0031] Where S(θ) represents the precise horizontal angle characterized by the deflection angle value; imag represents taking the imaginary part; E Δ Indicates the difference channel data; E Σ b1 represents the sum of the received data of the array elements belonging to the first channel; b2 represents the sum of the received data of the array elements belonging to the second channel.

[0032] Furthermore, the process of obtaining the pitch angle is as follows:

[0033] The signal amplitude variation curve over time is obtained by fitting the signal power amplitude.

[0034] The pitch angle variation curve over time was obtained by fitting the pitch angle variation of the two-dimensional turntable.

[0035] The pitch angle of the suspected target is determined based on the pitch angle corresponding to the maximum pitch value.

[0036] Furthermore, the antenna array is configured with two parallel first channels and second channels;

[0037] The signal frequency of the first channel is 300MHz-4GHz;

[0038] The signal frequency of the second channel is 4GHz-6GHz.

[0039] In the second aspect, a radio detection system for low-speed small unmanned aerial vehicles (UAVs) is provided. This system is used to implement the radio detection method for low-speed small UAVs as described in any one of the first aspects, including an antenna array, a switch matrix, a radio frequency receiver, an analog-to-digital converter module, a two-dimensional turntable, and a signal processing board.

[0040] Furthermore, the antenna array is divided into two loop antennas, which correspond one-to-one with the first channel and the second channel;

[0041] The loop antenna consists of an antenna array of 8-12 sub-antennas arranged in a loop, with the first channel corresponding to 12 sub-antennas and the second channel corresponding to 8 sub-antennas;

[0042] The loop antenna corresponding to the first channel is located below the loop antenna corresponding to the second channel, and the diameter of the loop antenna corresponding to the first channel is larger than the diameter of the loop antenna corresponding to the second channel.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The radio detection method for low-speed and small UAVs provided by the present invention adopts antenna array detection combined with a two-dimensional turntable. The signal processing board switches the matrix and calculates the horizontal direction angle of the UAV through amplitude comparison direction finding and single pulse angle measuring algorithms. The pitch angle of the UAV is calculated by judging the signal amplitude of the UAV by controlling the pitch angle rotation of the two-dimensional turntable, thereby obtaining the angles of the UAV in two directions.

[0045] 2. This invention obtains a rough horizontal direction by amplitude comparison and then calculates the precise horizontal angle of the UAV by single-pulse angle measurement based on the obtained parameters, thereby obtaining a more accurate horizontal angle of the suspected UAV.

[0046] 3. The pitch angle measurement technology in this invention is a power amplitude detection method. It uses a slowly rotating turntable combined with power sampling of the UAV signal to obtain a power amplitude curve, and fits the pitch angle of the turntable to obtain the pitch angle of the suspected UAV. Attached Figure Description

[0047] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0048] Figure 1 This is an overall flowchart of an embodiment of the present invention;

[0049] Figure 2 This is a schematic diagram of the angle measurement curve in an embodiment of the present invention;

[0050] Figure 3 This is a system block diagram in an embodiment of the present invention;

[0051] Figure 4 This is a schematic diagram of the antenna array structure in an embodiment of the present invention;

[0052] Figure 5 This is a schematic diagram of the antenna array installation structure in an embodiment of the present invention;

[0053] Figure 6 This is a diagram illustrating the configuration of the host computer software module in an embodiment of the present invention. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0055] Example 1: Radio detection method for low-speed, small unmanned aerial vehicles, such as Figure 1 As shown, it includes the following steps:

[0056] S1: After the device completes its power-on self-test, it enters the detection mode to detect spatial radio waves within a 360° omnidirectional coverage area around the device in real time.

[0057] S2: During detection, the signal processing board controls the corresponding antenna elements in the antenna array by controlling the switching matrix of the corresponding channel;

[0058] S3: The downconversion path and analog-to-digital conversion module of the radio frequency transceiver process the data of the suspicious target to obtain a digital signal;

[0059] S4: The signal processing board performs amplitude comparison, direction finding, single-pulse angle finding, and spectrum identification processing on the digital signal to obtain information on the horizontal direction, frequency, amplitude, and modulation mode of the suspicious target;

[0060] S5: The two-dimensional turntable rotates in the horizontal direction and determines the pitch angle of the UAV based on the signal power amplitude.

[0061] S6: The signal processing board reports all data of the suspected target to the command and control center for graphic display.

[0062] It should be noted that the spectrum processing algorithm mainly processes the frequency, bandwidth, amplitude, and modulation method of the identified suspicious signals. The signal processing methods used include down-conversion, sampling, AD conversion, clutter filtering, etc., which will not be elaborated here.

[0063] Specifically, the two-dimensional turntable is set to 0 pitch angle by default. When a target is detected, the signal processing board controls the antenna array and other units to calculate the horizontal direction angle of the UAV. Then, the signal processing board controls the two-dimensional turntable to rotate horizontally to that angle and rotates from 0 to 90 degrees to calculate the pitch angle. When the position of the flying target changes, the two-dimensional turntable is reset to 0 pitch angle to continue subsequent steps such as horizontal angle measurement.

[0064] This invention can detect information such as the horizontal angle, pitch angle, approximate distance, and spectrum information (partially revealing the aircraft model) of a drone within a certain range using a single terminal. The background software supports functions such as graphic display, alarm reminders, blacklist / whitelist settings, trajectory playback, and storage export. At the same time, power consumption, size, and weight are controlled, and it is easy to set up.

[0065] In this embodiment, the process of obtaining the horizontal direction of the suspicious target is as follows: the amplitude comparison direction finding algorithm is used to determine the preliminary horizontal angle range of the suspicious target; the single pulse angle finding algorithm is used to calculate the precise horizontal angle of the suspicious target within the preliminary direction range value, so as to locate the horizontal direction of the suspicious target.

[0066] The process of determining the preliminary horizontal angle range is as follows: The preliminary horizontal angle of the suspected target is calculated using an amplitude-comparison direction-finding algorithm; the preliminary horizontal angle is then adjusted for fluctuations based on the equipment error value to obtain the preliminary horizontal angle range. For example, if the preliminary horizontal angle is A and the equipment error value is B, then the preliminary horizontal angle range is [AB, A+B]. Furthermore, the preliminary horizontal angle range can also be obtained by adjusting a lower limit setting C and an upper limit setting D, such as a preliminary horizontal angle range of [AC, A+D].

[0067] The specific formula for calculating the preliminary horizontal angle is as follows:

[0068]

[0069] in, θ represents the initial horizontal angle characterized by the angle of the incident signal. r θ represents the half-power beamwidth of the pattern function. s The angle between adjacent antennas is represented by R; R represents the logarithmic voltage ratio, measured in decibels.

[0070] In this embodiment, the calculation process for the precise horizontal angle specifically involves: establishing a monotonically changing angle measurement curve, such as... Figure 2 As shown, its vertical coordinate value corresponds one-to-one with the deflection angle; the difference and ratio between the two channels are calculated using a single-pulse angle measurement algorithm; based on the difference and ratio, the deflection angle value of the target being measured is selected from the angle measurement curve as the precise horizontal angle.

[0071] The specific formula for calculating the difference and ratio between the two channels is as follows:

[0072]

[0073] E Σ =b1+b2

[0074] E Δ =b1-b2

[0075] Where S(θ) represents the precise horizontal angle characterized by the deflection angle value; imag represents taking the imaginary part; E Δ Indicates the difference channel data; E Σ b1 represents the sum of the received data of the array elements belonging to the first channel; b2 represents the sum of the received data of the array elements belonging to the second channel.

[0076] The process of obtaining the pitch angle is as follows: the signal amplitude variation curve over time is obtained by fitting the signal power amplitude; the pitch angle variation curve over time is obtained by fitting the pitch angle variation of the two-dimensional turntable; and the pitch angle of the suspected target is determined based on the pitch angle corresponding to the maximum amplitude.

[0077] In this embodiment, the antenna array is configured with two parallel first channels and second channels; the signal frequency of the first channel is 300MHz-4GHz; and the signal frequency of the second channel is 4GHz-6GHz.

[0078] Example 2: A radio detection system for low-speed, small unmanned aerial vehicles (UAVs), which implements the radio detection method for low-speed, small UAVs described in Example 1, such as... Figure 3 As shown, it includes an antenna array, a switch matrix, an RF receiver, an analog-to-digital converter module, a two-dimensional turntable, and a signal processing board.

[0079] like Figures 3-5 As shown, the antenna array consists of two loop antennas, each corresponding to a first channel and a second channel. Each loop antenna comprises 8-12 sub-antennas arranged in a ring, with 12 sub-antennas corresponding to the first channel and 8 sub-antennas corresponding to the second channel. The loop antenna corresponding to the first channel is located below the loop antenna corresponding to the second channel, and the diameter of the loop antenna corresponding to the first channel is larger than the diameter of the loop antenna corresponding to the second channel. The first and second channels can operate independently or simultaneously.

[0080] Specifically, the antenna array is a 360° loop antenna array capable of receiving wireless signals in all directions from 0° to 360°. The switch matrix connects 20 antenna ports and controls the switching of antenna element channels. The RF receiver processes the received spatial signals through down-conversion and outputs an intermediate frequency (IF) signal, which is then processed by the analog-to-digital converter (ADC). The ADC receives the IF signal processed by the receiver, performs calculations, and outputs a digital signal for processing by the main signal processing control board. The 2D turntable can rotate in pitch angle, receives control commands from the signal processing board, and reports the real-time angle. The signal processing board processes the digital signals received by this channel in real time, calculates data such as direction, frequency, amplitude, and turntable angle based on the background algorithm, and reports this data to the command and control center for graphical display. It also coordinates the control of the switch matrices for each channel and monitors the operational status of each module, reporting the results to the command and control center.

[0081] It should be noted that the entire system consists of detection equipment and host computer software, with the equipment installed in a rack-mounted manner. The system software includes embedded software on the equipment's signal processing board and display and control software running on the host computer. The embedded software mainly identifies and processes information such as the direction and spectrum of suspicious detection targets, and controls and interacts with other hardware modules. The display and control software mainly visualizes the data reported by the equipment and issues control commands.

[0082] like Figure 6 As shown in this embodiment, the host computer software operates based on network communication, adopting a client / server architecture with four layers. It primarily enables data interaction between devices, data visualization processing, and data storage. During data interaction, the network communication status needs to be monitored in real time, providing feedback on the current communication status. Visualization processing displays information about detected suspicious targets in text and graphics, and supports data playback and export, as well as audible and visual alarms. It also supports user permission management, blacklist / whitelist modification, storage, and logging functions.

[0083] In this embodiment, the equipment structural components are made of ABS engineering plastic with a powder-coated outer surface. It consists of two parts: the main unit and the two-dimensional turntable, which are connected for data and power via connecting cables. Various module units are installed inside the main unit. The antenna array and switch matrix are integrated into the upper part of the equipment, while the RF receiver, analog-to-digital converter module, signal processing board, power module, etc., are arranged in a separate row, close to the bottom of the equipment. The bottom uses a plate-type heat sink for heat dissipation, ensuring safety during long-term operation.

[0084] Working Principle: This invention employs an antenna array detection system combined with a two-dimensional turntable. A signal processing board switches a matrix of switches, using amplitude comparison direction finding and single-pulse angle measurement algorithms to calculate the drone's horizontal direction angle. The drone's pitch angle is calculated by controlling the rotation of the two-dimensional turntable to assess the drone's signal amplitude, thus obtaining the drone's angles in two directions. Furthermore, after obtaining a rough horizontal direction through amplitude comparison direction finding, single-pulse angle measurement is used to further calculate the drone's precise horizontal angle based on the obtained parameters, thus obtaining a more accurate horizontal angle for suspected drones. Additionally, the pitch angle measurement technology is a power amplitude detection method. It utilizes a slowly rotating turntable combined with power sampling of the drone's signal to obtain a power amplitude curve, which is then fitted to the turntable's pitch angle to obtain the pitch angle of the suspected drone.

[0085] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0086] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0087] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0088] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0089] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A radio detection method for low-altitude, slow-moving, and small unmanned aerial vehicles (UAVs), characterized by: Includes the following steps: After the device completes its power-on self-test, it enters detection mode to detect spatial radio waves within a 360° omnidirectional coverage area around the device in real time. During detection, the signal processing board controls the corresponding antenna elements in the antenna array by controlling the switching matrix of the corresponding channel; The downconversion path and analog-to-digital conversion module of the radio frequency transceiver process the data of the suspected target to obtain a digital signal; The signal processing board performs amplitude comparison, direction finding, single-pulse angle finding, and spectrum identification on the digital signal to obtain information on the horizontal direction, frequency, amplitude, and modulation mode of the suspicious target. The two-dimensional turntable rotates in the horizontal direction and determines the pitch angle of the UAV based on the signal power amplitude. The signal processing board reports all data of the suspected target to the command and control center for graphic display; The process of obtaining the horizontal direction of the suspicious target is as follows: The preliminary horizontal angle range of the suspected target was determined using an amplitude comparison direction finding algorithm; The precise horizontal angle of the suspicious target is calculated within the initial direction range using a single-pulse angle measurement algorithm, so as to locate the horizontal direction of the suspicious target; The calculation process for the precise horizontal angle is as follows: Establish a monotonically changing angle measurement curve; The difference and ratio between the two channels are calculated using a single-pulse angle measurement algorithm; The deflection angle of the target object is selected from the angle measurement curve based on the difference and ratio as the precise horizontal angle.

2. The radio detection method for low-speed, small unmanned aerial vehicles according to claim 1, characterized in that, The process of determining the preliminary horizontal angle range is as follows: The preliminary horizontal angle of the suspected target was calculated using the amplitude comparison direction finding algorithm; The initial horizontal angle is adjusted by adjusting the fluctuation based on the equipment error value to obtain the initial horizontal angle range.

3. The radio detection method for low-speed, small unmanned aerial vehicles according to claim 2, characterized in that, The specific formula for calculating the preliminary horizontal angle is as follows: in, θ represents the initial horizontal angle characterized by the angle of the incident signal. r θ represents the half-power beamwidth of the pattern function. s The angle between adjacent antennas is represented by R; R represents the logarithmic voltage ratio, measured in decibels.

4. The radio detection method for low-speed, small unmanned aerial vehicles according to claim 3, characterized in that, The specific formula for calculating the difference and ratio between the two channels is as follows: E Σ =b1+b2 E Δ =b1-b2 Where S(θ) represents the precise horizontal angle characterized by the deflection angle value; imag represents taking the imaginary part; E Δ Indicates the difference channel data; E Σ b1 represents the sum of the received data of the array elements belonging to the first channel; b2 represents the sum of the received data of the array elements belonging to the second channel.

5. The radio detection method for low-speed, small unmanned aerial vehicles according to claim 1, characterized in that, The process of obtaining the pitch angle is as follows: The signal amplitude variation curve over time is obtained by fitting the signal power amplitude. The pitch angle variation curve over time was obtained by fitting the pitch angle variation of the two-dimensional turntable. The pitch angle of the suspected target is determined based on the pitch angle corresponding to the maximum pitch value.

6. The radio detection method for low-speed, small unmanned aerial vehicles according to claim 1, characterized in that, The antenna array is configured with two parallel first channels and second channels; The signal frequency of the first channel is 300MHz-4GHz; The signal frequency of the second channel is 4GHz-6GHz.

7. A radio detection system for low-altitude, slow-moving, and small unmanned aerial vehicles (UAVs), characterized by: The system is used to implement the radio detection method for low-speed small unmanned aerial vehicles as described in any one of claims 1-6, including an antenna array, a switch matrix, a radio frequency receiver, an analog-to-digital converter module, a two-dimensional turntable, and a signal processing board.

8. The radio detection system for low-speed, small unmanned aerial vehicles according to claim 7, characterized in that, The antenna array is divided into two ring antennas, which correspond one-to-one with the first channel and the second channel. The loop antenna consists of an antenna array of 8-12 sub-antennas arranged in a loop, with the first channel corresponding to 12 sub-antennas and the second channel corresponding to 8 sub-antennas; The loop antenna corresponding to the first channel is located below the loop antenna corresponding to the second channel, and the diameter of the loop antenna corresponding to the first channel is larger than the diameter of the loop antenna corresponding to the second channel.

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