A method for detecting a communication jamming source based on multi-array direction finding of an unmanned aerial vehicle communication anti-radiation device

Abstract

This invention discloses a UAV communication anti-radiation device and a method for detecting communication interference sources based on multi-element direction finding. The device includes a direction-finding antenna array for receiving electromagnetic signals in space and capturing the azimuth characteristics, amplitude, and phase information of these signals; a multi-channel synchronous receiver for synchronous transmission of electromagnetic signals; an integrated signal processing module for synchronous sampling of multi-channel signals, digital signal processing, interference detection, direction finding calculation, and result fusion; a time-slot synchronous data link module for outputting timing reference signals for device operation scheduling; a comprehensive telemetry and control terminal for parameter configuration, status monitoring, visualization display, and self-test control; and a flight control interface for outputting interference source information to the UAV flight control system, providing guidance for UAV countermeasures. This invention achieves high-precision positioning of multiple co-frequency interference sources in complex electromagnetic environments through multi-module collaborative design, while also possessing system anti-interference capabilities, convenient platform integration, and full-scenario adaptability.

Description

Technical Field

[0001] This invention relates to the field of monitoring and direction finding technology, and in particular to a UAV communication anti-radiation device and a method for detecting communication interference sources based on multi-element direction finding. Background Technology

[0002] Unmanned aerial vehicles (UAVs), with their advantages of maneuverability, flexibility, and convenient deployment, have been widely used in various fields such as reconnaissance and mapping, logistics transportation, and emergency rescue. The reliability of their missions highly depends on the wireless link to realize core functions such as remote control command transmission, telemetry data feedback, real-time image transmission, and satellite navigation and positioning. Currently, the commonly used communication and navigation frequency bands for UAVs are mainly concentrated in the 2.4GHz and 5.8GHz open frequency bands and GNSS L1 / L2 navigation frequency bands. These frequency bands are widely used due to their strong openness and good compatibility, but they also face serious electromagnetic interference problems. Whether it is unintentional interference from devices on the same frequency or intentional blocking by malicious interference sources, it may cause control failure, data transmission interruption, navigation deviation, or even crashes of UAVs, seriously threatening mission safety and equipment and property safety.

[0003] To address the aforementioned interference issues, various anti-radiation or anti-interference devices have emerged in the industry. However, several shortcomings remain in practical applications: First, insufficient direction-finding accuracy and resolution. Existing devices often employ traditional direction-finding algorithms and simple antenna arrays, making it difficult to accurately locate interference sources and providing reliable guidance for UAVs. Second, weak multi-signal resolution capabilities. In complex electromagnetic environments, when multiple co-frequency interference sources exist simultaneously, existing devices are prone to signal confusion, tracking loss, and poor anti-interference stability. Third, a lack of adaptive and collaborative capabilities. The devices operate in a single, fixed mode, unable to dynamically adjust operating parameters based on UAV communication link status and mission phase. This can easily lead to mutual interference with the UAV's own communication signals or difficulty in quickly adapting to changes in interference scenarios. Fourth, poor system integration and scalability. Existing devices are mostly closed designs with inconsistent hardware interfaces and low modularity of software algorithms, making it difficult to flexibly adapt to the flight control systems and mission payloads of different UAV models. Subsequent functional upgrades and platform migrations are costly.

[0004] Therefore, developing an airborne communication anti-radiation device with high-precision positioning, strong multi-source resolution, dynamic coordination with UAVs, and easy integration and expansion has become a key requirement for solving the current electromagnetic interference problem of UAVs and improving their mission reliability in complex environments, and has important engineering application value.

[0005] The disclosure of the above background technical content is only for the purpose of assisting in understanding the concept and technical solution of this application, and does not necessarily provide technical instruction. Summary of the Invention

[0006] The purpose of this invention is to provide a UAV communication anti-radiation device and communication interference source detection method based on multi-element direction finding. Through multi-module collaborative design, it can achieve high-precision positioning of multiple co-frequency interference sources in complex electromagnetic environments, and has the advantages of system anti-interference capability, convenient platform integration and full-scenario adaptability.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A UAV communication anti-radiation device based on multi-element direction finding includes a direction finding antenna array, a multi-channel synchronous receiver, an integrated signal processing module, a time-slot synchronous data link module, an integrated telemetry and control terminal, and a flight control interaction interface. The direction-finding antenna array is a multi-element array used to receive electromagnetic signals in space and capture the azimuth characteristics, amplitude, and phase information of the electromagnetic signals. The multi-channel synchronous receiver is used to preprocess and synchronously transmit the electromagnetic signals received by the direction-finding antenna array in the L / S band, 2.4 GHz, 5.8 GHz and GNSS L1 / L2 band. The integrated signal processing module integrates a high-speed analog-to-digital converter, a programmable logic unit, and a processor unit, and is used for multi-channel signal synchronous sampling, digital signal processing, interference detection, direction finding calculation, and result fusion. The time slot synchronization data link module is used to output a timing reference signal that is synchronized with the UAV's communication time slot and to schedule the working cycle of the anti-radiation equipment to avoid mutual interference within the system. The integrated measurement and control terminal is connected to the integrated signal processing module and is used for parameter configuration, status monitoring, visualization display and self-test control. The flight control interface is used to output interference source information to the UAV flight control system through a standardized communication interface, providing guidance for the UAV's countermeasure actions.

[0008] Furthermore, based on any or a combination of the aforementioned technical solutions, the 6-element non-uniform linear array can adapt to different fixed-wing aircraft models, maximizing its conformity with the aircraft. The beam coverage of the direction-finding antenna array is 180° horizontal azimuth. The pitch angle is -50 degrees. ~5 The array element is a broadband antenna with a voltage standing wave ratio ≤1.6 and a gain ≥1.8dBi. The spacing between the array elements is half the center wavelength of the corresponding operating frequency band.

[0009] Furthermore, based on any one or a combination of the aforementioned technical solutions, the multi-channel synchronous receiver includes a limiting protection unit, an adjustable attenuation unit, a switchable frequency band filtering unit, a signal amplification unit, and an anti-aliasing filtering unit.

[0010] Furthermore, based on any or a combination of the aforementioned technical solutions, the high-speed analog-to-digital conversion unit of the integrated signal processing module is a high-speed analog-to-digital converter; The programmable logic processing unit is a programmable logic device used to perform digital downconversion, point sampling, FFT transformation and spatial smoothing. The processor unit is responsible for interference detection, model order estimation, direction finding calculation, confidence assessment, and result fusion.

[0011] Furthermore, following any or a combination of the aforementioned technical solutions, the integrated signal processing module further includes a periodic self-calibration unit, used to automatically trigger channel amplitude and phase calibration according to a preset time interval or temperature change threshold, generate and store correction coefficients, and compensate for amplitude and phase errors in real-time sampled data.

[0012] Furthermore, based on any or a combination of the aforementioned technical solutions, the interference source information includes the interference source location, timestamp, confidence level, and tag information; The standardized communication interface is RS485, Ethernet or CAN interface, which supports real-time data transmission and heartbeat interaction. The integrated measurement and control terminal provides spectrum visualization, operation log recording, and calibration information storage functions.

[0013] According to another aspect of the present invention, the present invention provides a method for detecting communication interference sources on unmanned aerial vehicles (UAVs), applied to the UAV communication anti-radiation equipment as described in any of the preceding claims, characterized in that it includes the following steps: S1: The device is powered on and initialized, completing receiver channel self-test, clock calibration and time slot synchronization. The direction-finding antenna array receives spatial electromagnetic signals and transmits them to the multi-channel synchronous receiver. S2: After the multi-channel synchronous receiver preprocesses the signal, it is transmitted to the integrated signal processing module for synchronous digital sampling; S3: The integrated signal processing module initiates a self-calibration process, generates channel amplitude and phase correction coefficients, and performs error compensation on the real-time sampled data; S4: Based on energy threshold and constant false alarm rate detection, combined with signal spectrum characteristics and time slot relationships, interference signals are screened to eliminate non-target signals, including data transmission radiation. S5: The number of interference sources is determined by the model order estimation criterion. After preprocessing the coherent or multipath signal, the location of the interference source is calculated and the confidence level of the direction finding result is evaluated. S6: Perform peak selection and time series filtering on the direction finding results, and output high-confidence interference source information to the flight control system through the flight control interaction interface. The integrated measurement and control terminal synchronously displays relevant data and equipment status.

[0014] Furthermore, following any one or a combination of the aforementioned technical solutions, in step S3, the self-calibration process specifically involves: the integrated signal processing module internally synthesizing a stable reference signal, injecting it into each receiving channel via a power divider network, acquiring the output signal of each channel, calculating and storing the inter-channel amplitude and phase error compensation coefficients, and applying the compensation coefficients in real time to correct the sampled data.

[0015] Furthermore, following any one or a combination of the aforementioned technical solutions, in step S5, the model order estimation criterion is the MDL criterion or the AIC criterion; The calculation of the azimuth of the interference source is based on the spectrum estimation direction finding algorithm, which is the MUSIC algorithm and supports the azimuth estimation of no less than 4 co-frequency interference sources. The preprocessing includes spatial smoothing, which is used to improve the resolution of coherent signals.

[0016] Furthermore, following any one or a combination of the aforementioned technical solutions, the method also includes a working mode switching step: the equipment can switch between mission mode, ground joint testing mode, and test mode; In mission mode, remote control interference and satellite interference are detected separately based on the UAV communication time slot. Remote control interference is detected outside the transmission time slot, and satellite interference is detected during the transmission time slot. In the ground-based joint test mode, the anti-radiation equipment outputs spectrum data, raw data, and real-time direction finding results via network for test analysis; In test mode, the anti-radiation device performs fixed-frequency or sweep-frequency tests, can operate independently of the drone, and complete full-function self-test.

[0017] The beneficial effects of the technical solution provided by this invention are as follows: a. High direction finding accuracy and strong multi-source resolution capability: It adopts a six-element conformal antenna array with MUSIC high-resolution direction finding algorithm, combined with periodic channel amplitude and phase self-calibration mechanism. Under the condition of SNR≥10dB, the root mean square error of azimuth is better than 1°. It can stably distinguish no less than 4 co-frequency interference sources and accurately cope with complex electromagnetic environment. b. Good adaptive coordination and reliable anti-interference: Timing scheduling is achieved through data link time slot synchronization pulses, and sampling and direction finding are completed within the data transmission window, effectively avoiding mutual interference within the system; It supports periodic detection of remote control and satellite interference, adapts to different mission states of UAVs, and improves detection sensitivity and stability in complex scenarios; c. Convenient integration and expansion with full lifecycle adaptability: It adopts standardized hardware interfaces and modular software design, and the algorithm can be customized and upgraded, making it easy to integrate with flight control systems of different platforms; it covers multiple modes such as in-flight missions, ground joint testing, and single-aircraft testing, covering the entire process from R&D verification to field deployment, and is highly practical. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the structure of an unmanned aerial vehicle (UAV) communication anti-radiation device based on multi-element direction finding, provided as an exemplary embodiment of the present invention; Figure 2 A schematic diagram of the workflow of an anti-radiation device for unmanned aerial vehicle (UAV) communication is provided as an exemplary embodiment of the present invention. Figure 3 A schematic diagram illustrating the working principle of an anti-radiation device provided as an exemplary embodiment of the present invention; Figure 4 An installation diagram provided for an exemplary embodiment of the present invention; Figure 5 A device host diagram provided for an exemplary embodiment of the present invention; Figure 6 A schematic diagram of the interference detection cycle provided for an exemplary embodiment of the present invention; Figure 7 A schematic diagram of a UAV-based communication interference source detection method provided as an exemplary embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the 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 a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0022] In one embodiment of the present invention, such as Figure 1 As shown, a UAV communication anti-radiation device based on multi-element direction finding is provided, including a direction-finding antenna array, a multi-channel synchronous receiver, an integrated signal processing module, a time-slot synchronous data link module, a comprehensive telemetry and control terminal, and a flight control interface. The direction-finding antenna array is a multi-element array used to receive electromagnetic signals in space and capture the azimuth characteristics, amplitude, and phase information of the electromagnetic signals. The multi-channel synchronous receiver is used to perform precise preprocessing and synchronous transmission of the electromagnetic signals received by the direction-finding antenna array. The integrated signal processing module integrates a high-speed analog-to-digital converter and a programmable logic unit. The system includes a processor unit for multi-channel signal synchronous sampling, digital signal processing, interference detection, direction finding calculation, and result fusion; a time-slot synchronization data link module for outputting a timing reference signal synchronized with the UAV's communication time slot and scheduling the equipment's operating cycle to avoid mutual interference within the system; a comprehensive telemetry and control terminal connected to the integrated signal processing module via a wired or wireless network for parameter configuration, status monitoring, visualization display, and self-test control; and a flight control interaction interface for outputting interference source information to the UAV flight control system through a standardized communication interface, providing guidance for UAV countermeasures.

[0023] This invention, through the collaborative design of core structures such as a direction-finding antenna array, a multi-channel synchronous receiver, and an integrated signal processing module, possesses significant advantages: The multi-element conformal antenna array, combined with wide-beam coverage and the signal preprocessing and high-precision synchronous transmission capabilities of the multi-channel synchronous receiver, can capture electromagnetic signals in all frequency bands related to UAV communication and navigation, effectively supporting multi-signal resolution; the periodic self-calibration function of the integrated signal processing module is deeply integrated with the spectrum estimation direction-finding algorithm, and coupled with the timing scheduling mechanism of the time-slot synchronous data link module, it achieves 1°-level high-precision positioning against at least four co-frequency interference sources in complex electromagnetic environments, while avoiding internal system interference and improving detection reliability; the standardized flight control interface and multi-working-mode design not only make the equipment easy to integrate and expand with different UAV platforms, but also cover the entire process of mission execution, ground joint testing, and single-unit testing, significantly improving engineering practicality and scenario adaptability.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and practical application scenarios, to ensure that those skilled in the art can implement device deployment and functional applications based on the following content. See the attached drawings. Figure 1-5 : Exemplary Example 1: Anti-radiation device embodiment Device hardware configuration The anti-radiation device in this embodiment is compatible with quadcopter drones and is fixed to the drone using a custom carbon fiber bracket. The wing bracket adopts a quick-release structure, which does not affect the drone's endurance or aerodynamic performance. The specific configuration of each module is as follows: Six-element direction-finding antenna array: Utilizing a linear array layout, the array elements are Vivaldi antennas, operating in the 1GHz–4GHz frequency band (L / S band), with a voltage standing wave ratio (VSWR) ≤1.6 and a gain ≥1.8dBi. The antenna array is conformal to the UAV's wing, with beam coverage of -90° to +90° horizontally and -50° to 5° vertically. Each element is equipped with a waterproof and dustproof housing, adapting to complex outdoor environments.

[0025] Six-channel synchronous receiver: Features a modular design, integrated within an aluminum alloy chassis; operating temperature range: -45°C to +55°C. Six-channel synchronous receiver (RF front end): 140*55*38.

[0026] The six independent RF channels are structured as follows: PIN diode limiter (maximum power handling 20dBm), digital attenuator (adjustable from 0 to 31.5dB, in 0.5dB steps), dual-band filter bank (L / S band switching), low-noise amplifier (noise figure ≤1.0dB, gain ≥22dB), programmable gain amplifier (-10 to 30dB adjustable), and 8th-order anti-aliasing filter (cutoff frequency L band 2.1GHz, S band 4.1GHz).

[0027] Integrated signal receiving and processing board: Non-domestic seven-channel 5000M acquisition dual-channel 9800M playback Z9 (RFSOC) CNC board, with one Zybq UltraScale+RDSoCs (XCZU47DR-2FFVE1156I) processing chip, which is equipped with two 2GbFLASH chips, three 2GB DDR chips (one for PS end and two for PL end), one 128GB EMMC, and an Hmc7044 clock chip.

[0028] The ZU47DR has eight acquisition and processing channels, six of which are used to achieve five-channel synchronous data acquisition and DDC.

[0029] The sampling rate is 4096 MSPS. The first Nyquist interval is 0-2048MHz, covering the first key frequency band of 1150-1620MHz, with a 428MHz margin for filter transition. The second Nyquist interval is 2048MHz-4096MHz, covering the second key frequency band, with a 302MHz margin for filter transition.

[0030] For example:

[0031] Power input range: 19V~31V; Typical power consumption: ≤60W; Communication methods: Ethernet port, RS422, RS232; Operating temperature: -45℃~+55℃; It has a total of 9 SMP RF interfaces, namely 6 AD input interfaces, 1 calibration signal output, and 1 clock interface; The board has two external control interfaces: one J30JZ-51 interface and one QSH interface. The J30JZ-51 interface can be used for power supply, RS232, RS422, JTAG, etc., while the QSH interface can be used for power supply and I / O ports.

[0032] Data Link Module: The selected UAV data link is a wireless broadband link product specifically developed for industrial-grade UAVs, integrating image, data transmission, and remote control. It features a variety of interfaces, long transmission distance, fast communication link establishment / recovery, and excellent electromagnetic compatibility. This product operates in the S-band and can establish / recover communication connections within 10ms, providing a two-way communication channel with a maximum communication distance of up to 50 kilometers (under line-of-sight conditions).

[0033] Utilizing advanced wireless digital communication technology, it boasts robust anti-interference capabilities, optimized communication protocol design, and high communication security. Specifically tailored to the needs of industrial-grade drones, it has undergone extensive optimization and improvement in areas such as electromagnetic compatibility, anti-interference, interface types, reliability, and environmental adaptability, providing a comprehensive solution for wireless communication between industrial-grade drones and the ground. It can simultaneously meet communication requirements such as high-definition image downlink and bidirectional transmission of remote control and telemetry data, achieving IP-based and integrated drone communication links. This solves the mutual interference problem caused by the use of multiple wireless devices in current industrial-grade drones, reducing the complexity of onboard communication equipment. Furthermore, while meeting current functional requirements, it provides better support for the diversification and standardization of drone payloads.

[0034] Features: Supports integrated transmission of images, data, and remote control information; It has radio ranging capabilities; The ground provides a directional antenna single-axis automatic tracking turntable. The turntable has manual, digital, and tracking functions, and supports listening to the aircraft's position information from flight control telemetry data and guiding the tracking turntable. It has link status display function; Airborne single antenna; The ground terminal has serial port server functionality. Performance metrics: Operating frequency band: S-band, 2360-2540MHz; Channel bandwidth: 20MHz; see the table above for channel number and center frequency. RF power: 2W; Transmission distance: up to 50 kilometers (under line-of-sight radio conditions); It also supports 1-2 channels of network image stream downlink, 4 channels of bidirectional data, and 2 channels of remote control uplink; Image channel bandwidth: 6.1Mbps; Airborne image interface: Ethernet port; Ground-side image interface: Ethernet port.

[0035] Integrated Measurement and Control Terminal: It adopts a 10-inch industrial panel PC, pre-installed with measurement and control software, and supports WiFi (2.4GHz) and wired Ethernet connections. It can realize functions such as parameter configuration, spectrum display, direction finding result visualization, and log recording. The software interface supports real-time updates of information such as interference source location, confidence level, and signal strength.

[0036] Flight controller interface: adopts RS485 standard interface, supports Modbus-RTU protocol, baud rate default 115200bps, data frame output to flight controller includes interference source azimuth (accuracy 0.1°), timestamp (accuracy 1ms), confidence level (0~100), tag information, data frame length 16 bytes, interface has built-in overvoltage and overcurrent protection circuit.

[0037] Equipment Workflow Signal reception and correction switching mechanism The spatial electromagnetic signals received by the six-element antenna unit are first input to the receiver's built-in correction source / switching switch module. This module includes a correction signal power divider and an RF switching switch, which can switch the signal path according to the current operating mode of the equipment. In operating mode: the switch is switched to the antenna signal path, and the electromagnetic signal received by the antenna directly enters the six-channel synchronous receiver for preprocessing; In calibration mode: the switch is switched to the correction signal path, and the stable reference signal synthesized inside the integrated signal processing module is divided equally by the six power divider units and synchronously injected into the six receiving channels for the calculation of the amplitude and phase error coefficients of the subsequent channels.

[0038] After powering on, the device automatically initializes, completing receiver channel self-test, clock calibration, and data link time slot synchronization. The initialization time is ≤25s. After initialization, it sends a ready signal to the telemetry and control terminal.

[0039] The data link module extracts the UAV's data transmission time slot information, generates a synchronization pulse, and controls the receiver to sample during the data transmission transmission window: the non-transmission time slot switches to the 2.4GHz remote control frequency band, and the transmission time slot switches to the 1575.42MHz GNSS L1 / L2 frequency band.

[0040] The processing board preprocesses the acquired IQ data (which is the quadrature component data of the signal, where the I component is the in-phase component of the signal and the Q component is the quadrature component of the signal, obtained by quadrature down-conversion and analog-to-digital conversion of the radio frequency signal, which can completely preserve the amplitude, phase and frequency characteristics of the original electromagnetic signal, and is the core data carrier for subsequent interference detection and direction finding calculation) by adding Hanning window, FFT transformation and power spectrum calculation. It identifies interference signals by constant false alarm rate (CFAR) detection algorithm and eliminates the data transmission signal itself by combining spectrum characteristics and time slot relationship.

[0041] It should be noted that the FPGA logic unit (PL) of the integrated signal processing module determines the current detection period (remote control interference detection period or satellite interference detection period) based on the timing reference signal output by the time slot synchronization data link module, and configures the receiver's operating frequency accordingly. Then, it starts the high-speed ADC for synchronous sampling and completes digital down-conversion processing through the built-in DDC module.

[0042] A system-on-a-chip integrating a high-speed analog-to-digital converter, programmable logic, and processor is employed. The programmable logic performs real-time processing such as six-channel synchronous sampling, digital down-conversion, decimation, and FFT. The processor system handles interference detection, model order estimation, direction finding calculation, result fusion, and external communication. Sampling and clock distribution utilize a common-reference high-stability source, with inter-channel sampling skew preferably not exceeding 100 ps and sampling jitter preferably not exceeding 300 fs rms (root mean square value of sampling clock jitter).

[0043] Each channel synchronously buffers N samples of broadband IQ data to form a data frame, which is then transmitted to the FPGA for preprocessing. The preprocessing process includes two steps: FFT Transformation and Correction Coefficient Extraction: After applying a Hanning window to the IQ data, an FFT transformation is performed to obtain complex spectrum data; the amplitude and phase differences between each channel are extracted from the complex spectrum as the basis for calculating the correction coefficients; at the same time, the power spectrum is calculated from the complex spectrum to provide data support for subsequent interference detection; Channel amplitude and phase error correction: The IQ data of each channel is multiplied by a pre-stored correction coefficient matrix to subtract the amplitude and phase errors between channels, so that the output IQ data truly reflects the amplitude and phase relationship of the antenna received signal.

[0044] The number of interference sources is estimated using the MDL criterion, the coherent signal is spatially smoothed, the azimuth is calculated using the MUSIC algorithm, the confidence level is evaluated (≥60 is a valid result), and the result is output through the flight control interface after Kalman filtering.

[0045] The flight controller generates avoidance or approach commands based on the interference source information, drives the UAV to move, and feeds back the status to the telemetry and control terminal. Operators can modify parameters such as detection threshold and calibration cycle in real time.

[0046] The flight control interface software has a built-in result filtering module that performs two-step optimization processing on the direction finding results output by the integrated signal processing module: Results filtering: Invalid direction finding results with a confidence level below 60 were removed, and only high-confidence interference source azimuth data were retained; Tracking filtering: The Kalman filter algorithm is used to perform time series smoothing on high-confidence azimuth data of multiple consecutive frames to reduce random errors and improve the stability of azimuth information.

[0047] The flight control module integrates the filtered interference source location information, the UAV's current position and attitude data, and the mission target area information, and generates control commands for avoidance or approach after comprehensive calculation, and sends them to the UAV flight control system.

[0048] If the device is connected to the integrated telemetry and control terminal, the flight control interface software will simultaneously send the UAV flight status information, interference source location information, UAV position and attitude information, and flight control commands to the terminal, realizing the visualization and storage of data.

[0049] Exemplary Example 2: Anti-radiation device embodiment Device hardware configuration This embodiment is adapted for lightweight fixed-wing UAVs, weighing 3.2kg and consuming ≤60W. It is fixed via an embedded mounting slot on the top of the fuselage, conforming to the fuselage design and not disrupting the aerodynamic layout. The core configuration differences are as follows: Six-element direction-finding antenna array: a non-uniform linear array. The horizontal spacing between the first and second antenna groups is 60mm, and the antenna aperture spacing is 56mm. The horizontal spacing between the second and third antenna groups is 110mm, and the antenna aperture spacing is 65mm. It is encapsulated in rigid foam, with a wind resistance rating ≥12m / s, an element gain ≥2.0dBi, a voltage standing wave ratio ≤1.5, and a beam coverage range consistent with Example 1.

[0050] Six-channel synchronous receiver: Optimized heat dissipation design, adopting passive heat dissipation + heat sink fin structure, operating temperature range -45℃~55℃; low noise amplifier uses GaN process chip (noise figure ≤0.8dB, gain ≥25dB), with stronger anti-interference capability, supporting fast switching attenuation in strong interference scenarios (switching time ≤15ns).

[0051] Integrated Signal Receiver and Processing Board: Utilizing the XCZU47DR-2FFVE1156I (RFSOC), this board integrates a high-performance RF signal chain, ARM processor, and FPGA logic onto a single chip. It supports direct RF sampling up to 6GHz, with an RF ADC sampling rate up to 5GSPS and 14-bit precision. It features a processing system consisting of a quad-core ARM Cortex-A53 and a dual-core Cortex-R5F, along with programmable logic containing 930k logic units and 4272 DSP units, supporting high-speed serial transceivers up to 28.21Gb / s. It can perform complex digital signal processing and system control.

[0052] Data link module: Communication distance extended to 20km, supports frequency hopping anti-interference technology, bit error rate ≤10 -6 (SNR≥8dB), suitable for long-distance flight requirements of fixed-wing UAVs.

[0053] Equipment core advantages Adapted to high-speed flight scenarios of fixed-wing UAVs, the device's stability is improved through optimized antenna packaging and heat dissipation design; the performance of the upgraded signal processing board ensures that it can still achieve 1°-level direction finding accuracy during high-speed flight, and can stably distinguish 4 co-frequency interference sources, meeting the anti-interference requirements of long-range reconnaissance missions.

[0054] Exemplary Example 3: Implementation of a detection method based on this device, see Appendix Figure 7 : This embodiment uses a multi-rotor UAV performing an outdoor reconnaissance mission as an example to explain in detail the method for detecting interference sources. The specific steps are as follows: Equipment deployment and parameter configuration: The anti-radiation device of Exemplary Example 1 is fixed to the belly of the quadcopter UAV using a quick-release bracket, and the power supply and flight control interface are connected; the operator sets the parameters through the telemetry and control terminal: detection threshold coefficient k=5, calibration cycle 1h, remote control interference detection frequency band 2.4GHz, satellite interference detection frequency band 1575.42MHz GNSS L1 / L2 band.

[0055] UAV takeoff and equipment startup: The UAV takes off to a preset altitude of 300m and flies at a speed of 25m~50m / s. The operator starts the equipment mission mode on the telemetry and control terminal, and the equipment automatically synchronizes the time slot with the UAV data transmission link.

[0056] Interference signal acquisition and calibration: The six-element antenna receives spatial signals, which are preprocessed by the receiver and then transmitted to the processing board. The equipment automatically starts channel amplitude and phase self-calibration at a 1-hour cycle. The processing board synthesizes reference signals and injects them into the six channels, calculates and stores correction coefficients, and compensates for channel errors in real time.

[0057] Interference detection and feature recognition: The processing board performs FFT transformation and power spectrum calculation on the collected IQ data, detects interference signals based on the CFAR algorithm, and eliminates the data transmission's own radiated signals by combining the signal bandwidth, spectrum shape and time slot relationship, and confirms 3 effective interference sources.

[0058] Interference source localization and result output: The number of targets is estimated to be 3 using the MDL criterion. The coherent signal is spatially smoothed (smoothing window size 3). The azimuths of the interference sources are calculated to be 25°, 140°, and 270° using the MUSIC algorithm, with confidence levels of 88, 92, and 75, respectively. After Kalman filtering, high-confidence results are output through the flight control interface.

[0059] Execution of UAV countermeasures: The flight control system combines the UAV's current position (latitude and longitude: 30.5°N, 120.3°E) and attitude to generate avoidance commands, controlling the UAV to turn 180° away from the dense area of ​​interference sources. During the turn, the equipment continuously monitors the status of the interference sources and updates the azimuth information in real time.

[0060] It should be noted that the result filtering module in the flight control interface software filters and tracks the results, outputting the current target bearing information. The flight control module, based on the aircraft position, target area, and target bearing information, performs comprehensive calculations and sends control commands to the flight controller. If connected to a telemetry and control terminal, the aircraft status information, target bearing information, aircraft position and attitude information, and flight control commands are sent to the telemetry and control terminal.

[0061] Data recording and task completion: The telemetry and control terminal records data such as the location of the interference source, confidence level, and signal spectrum in real time. After the task is completed, a detection report is automatically generated, and the data can be exported to Excel format for easy subsequent analysis.

[0062] It should be noted that the device can operate in three modes: mission mode, ground mission mode, and test mode.

[0063] Mission Mode: During time slots when no signal is transmitted from the airborne data transmission terminal, remote control interference is detected in the remote control operating frequency band. During time slots when the data transmission terminal transmits signals, GNSS L1 / L2 satellite frequency band interference is detected. Direction finding is performed on the interference signals to guide the UAV towards the target. The telemetry and control terminal can establish a connection with the equipment via the data transmission to receive the UAV's flight status, detection results, target azimuth information, and flight guidance information. Operating parameters can also be modified during the mission.

[0064] Ground mission mode: When the UAV is on the ground, the telemetry and control software also connects to the equipment via a wired network. After the mission mode is activated, the equipment will output more information for testing through the wired network. The additional information includes spectrum data, IQ data, and real-time direction finding results.

[0065] Test mode: The equipment is on a ground platform, which may or may not be on a drone. The ground control software is directly connected to the equipment via a network cable, and can perform fixed frequency and frequency sweeping operations to conduct full-function tests on the equipment.

[0066]

[0067] Interference detection cycle like Figure 6 As shown, because the receiving antenna and the airborne data transmission antenna are very close, the receiving link will saturate if the receiver is set to the data transmission frequency during data transmission. Therefore, based on the characteristics of the data transmission frame signal, the detection is divided into two periods: a satellite interference detection period and a remote control interference detection period. Remote control interference detection and direction finding are performed during the non-airborne transmission period, while satellite interference detection and direction finding are performed during the airborne transmission period.

[0068] Working mode / calibration mode The spectral estimation direction-finding algorithm requires phase consistency in the output signal of the receiving channel. Since a phase difference always exists in the physical receiving channel, channel calibration is necessary. In calibration mode, the calibration signal is sent to six receiving processing channels after being divided by an in-phase power divider. The amplitude and phase difference (represented by a complex number) of the output data is collected and measured, and this difference is used as the calibration coefficient. In operating mode, this calibration coefficient is applied to correct the real-time received data. The calibration coefficient is collected once upon device startup and then every time interval T thereafter.

[0069] This detection method achieves accurate detection and location of interference sources in complex electromagnetic environments through the collaborative work of equipment and UAVs. The direction finding accuracy is better than 1°, and it can stably distinguish multiple interference sources with the same frequency, providing a reliable guarantee for the safety of UAV missions.

[0070] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0071] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A UAV communication anti-radiation device based on multi-element direction finding, characterized in that, It includes a direction-finding antenna array, a multi-channel synchronous receiver, an integrated signal processing module, a time-slot synchronous data link module, an integrated telemetry and control terminal, and a flight control interaction interface; The direction-finding antenna array is a multi-element array used to receive electromagnetic signals in space and capture the azimuth characteristics, amplitude, and phase information of the electromagnetic signals. The multi-channel synchronous receiver is used to preprocess and synchronously transmit the electromagnetic signals received by the direction-finding antenna array. The integrated signal processing module integrates a high-speed analog-to-digital converter, a programmable logic unit, and a processor unit, and is used to perform synchronous sampling, digital signal processing, interference detection, direction finding calculation, and result fusion on multiple parallel signals transmitted through the multi-channel synchronous receiver. The time slot synchronization data link module is used to output a timing reference signal that is synchronized with the UAV's communication time slot and to schedule the working cycle of the anti-radiation equipment to avoid mutual interference within the system. The integrated measurement and control terminal is connected to the integrated signal processing module and is used for parameter configuration, status monitoring, visualization display and self-test control. The flight control interface is used to output interference source information to the UAV flight control system through a standardized communication interface, providing guidance for the UAV's countermeasure actions.

2. The UAV communication anti-radiation device based on multi-element direction finding according to claim 1, characterized in that, The direction-finding antenna array is a 4-8 element linear array or circular array, and the beam coverage horizontal azimuth angle of the direction-finding antenna array is... The pitch angle is - ~ The array element is a broadband antenna with a voltage standing wave ratio ≤1.6 and a gain ≥1.8dBi.

3. The UAV communication anti-radiation device based on multi-element direction finding according to claim 1, characterized in that, The multi-channel synchronous receiver includes an amplitude limiting protection unit, an adjustable attenuation unit, a switchable frequency band filtering unit, a signal amplification unit, and an anti-aliasing filtering unit.

4. The UAV communication anti-radiation device based on multi-element direction finding according to any one of claims 1-3, characterized in that, The high-speed analog-to-digital conversion unit of the integrated signal processing module is a high-speed analog-to-digital converter; The programmable logic processing unit is a programmable logic device used to perform digital downconversion, point sampling, FFT transformation and spatial smoothing. The processor unit is responsible for interference detection, model order estimation, direction finding calculation, confidence assessment, and result fusion.

5. The anti-radiation device for UAV communication based on multi-element direction finding according to claim 1, characterized in that, The integrated signal processing module also includes a periodic self-calibration unit, which is used to automatically trigger the calibration of amplitude gain and phase delay deviation of each radio frequency channel of the multi-channel synchronous receiver according to a preset time interval threshold or temperature change threshold, generate and store correction coefficients, and perform amplitude and phase error compensation on real-time sampled data.

6. The UAV communication anti-radiation device based on multi-element direction finding according to claim 1, characterized in that, The interference source information includes the interference source location, timestamp, confidence level, and tag information; The standardized communication interface is RS485, Ethernet or CAN interface, which supports real-time data transmission and heartbeat interaction. The integrated measurement and control terminal also provides spectrum visualization display, operation log recording, and calibration information storage functions.

7. A method for detecting communication interference sources on a UAV, applied to the UAV communication anti-radiation device according to any one of claims 1-6, characterized in that, Includes the following steps: S1: The device is powered on and initialized, and the multi-channel synchronous receiver completes channel self-test, clock calibration and time slot synchronization. The direction-finding antenna array receives spatial electromagnetic signals and transmits them to the multi-channel synchronous receiver. S2: After the multi-channel synchronous receiver preprocesses the signal, it is transmitted to the integrated signal processing module for synchronous digital sampling; S3: The integrated signal processing module initiates a self-calibration process, generates channel amplitude and phase correction coefficients, and performs error compensation on the real-time sampled data; S4: Based on energy threshold and constant false alarm rate detection, combined with signal spectrum characteristics and time slot relationships, interference signals are screened to eliminate non-target signals, including data transmission radiation. S5: Determine the number of interference sources, preprocess the coherent or multipath signals, calculate the azimuth of the interference sources, and evaluate the confidence level of the direction finding results; S6: Perform peak selection and time series filtering on the direction finding results, and output high-confidence interference source information to the UAV flight control system through the flight control interaction interface. The integrated measurement and control terminal simultaneously displays relevant data and equipment status.

8. The method for detecting communication interference sources based on unmanned aerial vehicles according to claim 7, characterized in that, In step S3, the self-calibration process is as follows: the integrated signal processing module synthesizes a stable reference signal, which is injected into the multiple independent radio frequency channels of the multi-channel synchronous receiver through the power divider network. The preprocessed signals output by the multiple independent radio frequency channels are used to calculate and store the inter-channel amplitude and phase error compensation coefficients, and the compensation coefficients are applied in real time to correct the sampling data.

9. The method for detecting communication interference sources based on unmanned aerial vehicles according to claim 7 or 8, characterized in that, In step S5, the number of interference sources is determined using the model order estimation criterion; The model order estimation criterion is either the MDL criterion or the AIC criterion; The calculation of the azimuth of the interference source is based on the spectrum estimation direction finding algorithm, which is the MUSIC algorithm and supports the azimuth estimation of at least 4 co-frequency interference sources. The preprocessing includes spatial smoothing, which is used to improve the resolution of coherent signals.

10. The method for detecting communication interference sources based on unmanned aerial vehicles according to claim 7, characterized in that, It also includes a working mode switching step: the device can switch between mission mode, ground joint test mode and test mode; In mission mode, remote control interference and satellite interference are detected separately based on the UAV communication time slot. Remote control interference is detected outside the transmission time slot, and satellite interference is detected during the transmission time slot. In the ground-based joint test mode, the anti-radiation equipment outputs spectrum data, raw data, and real-time direction finding results via network for test analysis; In test mode, the anti-radiation device performs fixed-frequency or sweep-frequency tests, can operate independently of the drone, and complete full-function self-test.

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