Vehicle-mounted GNSS (Global Navigation Satellite System) multi-interference source monitoring and direction finding device and monitoring and direction finding method

Abstract

The invention discloses a vehicle-mounted GNSS (Global Navigation Satellite System) multi-interference source monitoring and direction-finding device and a monitoring and direction-finding method, the device comprises a monitoring and direction-finding antenna and a monitoring and direction-finding host, the monitoring and direction-finding antenna comprises an antenna unit, a switch matrix, an electronic compass and an antenna controller, the antenna unit is electrically connected with the switch matrix, and the switch matrix is electrically connected with the electronic compass. The switch matrix and the electronic compass are electrically connected with the antenna controller respectively; the monitoring direction-finding host comprises a radio frequency receiving module, a signal processing module, a main control module and a power supply module. The monitoring and direction finding device disclosed by the invention is high in maneuverability, and can be carried on a vehicle platform to realize rapid monitoring and troubleshooting of interference sources in a certain area; the monitoring range is wide, satellite navigation interference signals in the vehicle driving range can be monitored in real time, and the detection range is wider than that of traditional handheld interference source monitoring and direction finding equipment.

Description

Technical Field

[0001] The invention belongs to the research field of satellite navigation multi-interference source monitoring and direction finding technology, and particularly relates to a vehicle-mounted GNSS multi-interference source monitoring and direction finding device and a monitoring and direction finding method in this field. Background Art

[0002] The Global Navigation Satellite System (GNSS) is widely used in aerospace, military, autonomous driving, surveying and mapping and other fields, bringing great convenience to human work and life. However, the landing level of satellite navigation signals is low and is easily affected by various interferences. Moreover, a large number of interference factors in the real environment will affect the transmission and reception of navigation signals, posing a huge challenge to the security and reliability of GNSS. Satellite navigation interference monitoring and direction finding technology is a key technology to improve and ensure the availability and reliability of navigation systems, and the development of monitoring and direction finding technology will also improve and perfect anti-interference technology, which is of great significance to my country's national defense and economic construction.

[0003] As the electromagnetic environment becomes increasingly complex, the existence of multiple interferences in space at the same time has become the norm. Traditional interference source monitoring and direction-finding equipment generally monitors and investigates a single interference source, which can no longer meet people's needs for monitoring multiple interference sources. Moreover, with the continuous improvement of interference countermeasure technology, distributed interference equipment that can counter multi-element nulling antennas in space through multiple interferences is becoming more and more popular. Traditional monitoring equipment is completely unable to cope with such interference equipment. Traditional interference source monitoring and direction-finding equipment has many problems such as complex system, difficult operation, limited monitoring range, inflexible deployment, and difficulty in monitoring and direction-finding multiple interference signals in a certain area. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a vehicle-mounted GNSS multi-interference source monitoring and direction-finding device and a monitoring and direction-finding method. By mounting the GNSS multi-interference source monitoring and direction-finding equipment on a vehicle platform, multiple interference source signals within a large range can be quickly and in real time monitored and direction-finded.

[0005] The present invention adopts the following technical solution: A vehicle-mounted GNSS multi-interference source monitoring and direction-finding device, the improvement of which lies in that it comprises a monitoring and direction-finding antenna and a monitoring and direction-finding host, the monitoring and direction-finding antenna comprises an antenna unit, a switch matrix, an electronic compass and an antenna controller, wherein the antenna unit is electrically connected to the switch matrix, and the switch matrix and the electronic compass are electrically connected to the antenna controller respectively; the monitoring and direction-finding host comprises a radio frequency receiving module, a signal processing module, a main control module and a power supply module, wherein the input end of the radio frequency receiving module is connected to communicate with the antenna controller, and the output end is electrically connected to the main control module through the signal processing module, and the power supply module supplies power to the monitoring and direction-finding antenna and the monitoring and direction-finding host.

[0006] Furthermore, the antenna unit adopts a uniformly distributed multi-element antenna array, and the antenna array element adopts a planar printed circuit board broadband dipole antenna.

[0007] Furthermore, the switch matrix includes multi-channel switches and small signal amplifiers.

[0008] Furthermore, the electronic compass is a high-precision three-dimensional digital compass that uses high-precision magnetoresistive sensors and inertial devices.

[0009] Furthermore, the control circuit of the antenna controller adopts FPGA.

[0010] Furthermore, the RF receiving module is an independent shell structure. Inside the RF receiving module, the external input signal is filtered by a segmented filter and then frequency-converted with the local oscillator 1 signal from the local oscillator unit to generate a first intermediate frequency signal. The signal is then filtered and amplified and then mixed with the local oscillator 2 signal. The mixed signal is transmitted to the intermediate frequency unit and the intermediate frequency signal is obtained after multiple stages of "filtering + attenuation + amplification + filtering" processing.

[0011] Furthermore, the signal processing module adopts the form of ADC+FPGA+DSP, and the ADC performs analog-to-digital conversion on the signal to obtain sampling data; the FPGA completes multi-channel combination processing of the sampling data, spectrum FFT processing of monitoring, DDC filtering extraction processing of direction finding, array element direction finding data combination accumulation processing, spectrum parameter estimation, direction finding parameter estimation and comprehensive control processing; the DSP completes direction finding signal sorting, signal format identification, and realizes integrated direction finding of the signal to be measured by comprehensively utilizing the spatial spectrum direction finding algorithm, interferometer direction finding algorithm and multi-beam direction finding algorithm, and completes the reporting of monitoring and direction finding data and the forwarding of comprehensive control commands; at the same time, it has an external clock input to provide a clock for signal processing; it has GPIO to realize peripheral control externally and communicate with an external computer through a 100M network.

[0012] Furthermore, the main control module is composed of a core processing unit, a power monitoring and control unit, a temperature and humidity monitoring unit, an abnormal warning processing unit, a parameter storage unit, a data transmission unit and a power supply unit, and the core processing unit is composed of an ARM processor and peripheral circuits.

[0013] A monitoring direction finding method, using the above-mentioned monitoring direction finding device, has the following improvements: The antenna unit receives electromagnetic waves radiated in 360° space with equal spacing, and transmits them to the back-end multi-channel switch and amplification circuit; the switch matrix controls the selection of channels to output the signals transmitted by the antenna unit to different RF output terminals; the electronic compass measures the antenna attitude in real time and outputs it to the antenna controller in real time; the antenna controller controls the channel selection of the switch matrix according to the instructions, and collects the electronic compass information and transmits it to the monitoring and direction finding host; The RF receiving module is responsible for receiving the interference signal received by the monitoring and direction-finding antenna. The receiving channel is five-channel. After low-noise amplification and pre-selection, superheterodyne mixing is performed and converted into an intermediate frequency signal for output to the signal processing module. The signal processing module receives the intermediate frequency signal output by the RF receiving module, and after analog-to-digital conversion, it processes and calculates to realize the monitoring of abnormal signals in the frequency band, signal analysis, direction finding and weak spread spectrum signal detection; the main control module controls each module to complete function initialization, receiver control, data analysis, data processing, data packaging, auxiliary underlying operations and data storage and transmission; the service performance monitoring algorithm is used to analyze and process the Beidou service performance monitoring results, and the interference monitoring direction-finding algorithm is used to analyze and process the interference monitoring direction-finding results, and the direction-finding results are stored locally; in addition, the main control module can also receive the monitoring mode and storage strategy issued by the upper node, and transmit interference monitoring data and interference direction-finding data to the upper node.

[0014] The beneficial effects of the present invention are: The monitoring and direction-finding device disclosed in the present invention has strong mobility and can be mounted on a vehicle platform to realize rapid monitoring and troubleshooting of interference sources within a certain area; it has a wide monitoring range and can monitor satellite navigation interference signals within the driving range of the vehicle in real time, and has a wider detection range than traditional handheld interference source monitoring and direction-finding equipment; it has a fast scanning speed and can monitor and direction-find multiple co-frequency interference signals that exist simultaneously in extreme cases.

[0015] The monitoring direction finding method disclosed in the present invention solves the shortcomings of the traditional monitoring direction finding method, such as high difficulty in operation, small monitoring range, inflexible deployment and only being able to monitor a single interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the working principle of the monitoring and direction finding device disclosed in the present invention; Figure 2 It is a block diagram of the components of the monitoring direction-finding antenna in the monitoring direction-finding device disclosed in the present invention; Figure 3 It is a block diagram of the components of the monitoring and direction finding host in the monitoring and direction finding device disclosed in the present invention; Figure 4 It is a diagram of direction finding results of multiple interference source monitoring; Figure 5 It is a flow chart of the monitoring and direction finding method disclosed in the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] Embodiment 1: This embodiment discloses a vehicle-mounted GNSS multi-interference source monitoring and direction finding device, such as Figure 1 As shown, it includes a monitoring direction finding antenna and a monitoring direction finding host, such as Figure 2 As shown, the monitoring direction-finding antenna includes an antenna unit, a switch matrix, an electronic compass, an antenna controller and a cable assembly, wherein the antenna unit is electrically connected to the switch matrix, the switch matrix and the electronic compass are electrically connected to the antenna controller respectively, and the cable assembly mainly interconnects the monitoring direction-finding antenna and the monitoring direction-finding host; the monitoring direction-finding antenna is mainly used to monitor the existing interference within the navigation frequency band and measure the direction of the interference signal. Figure 3 As shown, the monitoring and direction-finding host includes a radio frequency receiving module, a signal processing module, a main control module and a power module, wherein the input end of the radio frequency receiving module is connected to the antenna controller for communication, the output end is electrically connected to the main control module through the signal processing module, and the power module supplies power to the monitoring and direction-finding antenna and the monitoring and direction-finding host. The monitoring and direction-finding host is mainly used to process the environmental interference signal received by the monitoring and direction-finding antenna, and determine the direction of the incoming wave by measuring the incoming wave phase and phase difference of the interference signal, and obtain the interference direction-finding result. Functions include: interference signal monitoring, suppression of interference source direction-finding, suppression of interference signal parameter measurement and identification, management control, storage and transmission, etc. Special signals such as TACAN, LINK and 4G / 5G can be identified, and parameters such as frequency, bandwidth, power, signal-to-noise ratio of various signals can be measured. And the device has the function of setting interference database and black and white list. Through the interference database, interference alarm can be effectively carried out, other useful signals in the white list can be efficiently identified, and the monitored interference signals can be put into the black list, which can greatly improve the monitoring efficiency of this device.

[0019] The monitoring direction-finding antenna first receives the control command transmitted by the main control module in the monitoring direction-finding host. After receiving the control command, the antenna is started to monitor the existing interference within the navigation frequency band and measure the direction of the interference signal. The monitoring direction-finding antenna is controlled to monitor the spectrum of the GNSS key frequency band, and a certain reference threshold is set by the monitoring direction-finding host. Once the spectrum of the monitoring signal exceeds this threshold, it is considered that suppression interference is found, and the device issues an interference alarm. The monitoring direction-finding antenna is controlled to monitor the direction of the alarm signal, and the monitoring data is transmitted to the monitoring direction-finding host for signal feature analysis and processing. The monitoring and direction finding host receives the control instructions sent by the interference monitoring and direction finding software and transmits them to the monitoring and direction finding antenna, and then parses and processes the environmental signals received by the monitoring and direction finding antenna, thereby realizing interference direction finding; The interference monitoring and direction finding software is embedded in the main control module of the monitoring and direction finding host, and mainly realizes the functions of real-time display of monitoring results, setting of device working parameters, issuance of control instructions, storage and transmission of monitoring data, reception and analysis of monitoring data, and display of device working conditions. The interference monitoring and direction finding software sends monitoring and direction finding control instructions to the monitoring and direction finding host, and displays the monitoring data sent back by the monitoring and direction finding host in real time.

[0020] In this embodiment, the antenna unit adopts a uniformly distributed multi-element antenna array. The design principle of the antenna array element is to ensure that the horizontal plane radiation pattern of the array element does not have lobes in the frequency band range of 1GHz~3GHz, the low end has the highest possible gain, and adapts to the installation space structure of the multi-element. Therefore, the antenna array element is implemented using a planar printed circuit board broadband dipole antenna.

[0021] The main function of the multi-channel switch matrix is ​​to achieve interconnection or isolation between output channels and antenna channels through electronic switch switching according to the instructions issued by the host, and provide the RF signal received by each antenna for device direction finding. The switch matrix includes multi-channel switches and small signal amplifiers.

[0022] The electronic compass is a high-precision three-dimensional digital compass that uses high-precision magnetoresistive sensors and inertial devices. The electronic compass has the ability to compensate for large inclination angles and 360° continuous roll, and also has a temperature compensation effect to ensure that the accuracy is as little affected by the ambient temperature as possible. It has the characteristics of small size, high precision, and stable operation.

[0023] The control circuit of the antenna controller uses FPGA to complete the analysis of control commands and the control of each switch, and has the characteristics of fast control speed and low packet loss rate.

[0024] The RF receiving module is an independent shell structure, and it has the ability of each channel to work independently and the module self-test. In the RF receiving module, the external input signal is filtered by the segmented filter and then frequency-converted with the local oscillator 1 signal from the local oscillator unit to generate the first intermediate frequency point signal, which is then filtered and amplified before being mixed with the local oscillator 2 signal. The mixed signal is transmitted to the intermediate frequency unit, and the intermediate frequency signal is obtained after multi-stage "filtering + attenuation + amplification + filtering" processing. During the RF processing process, the monitoring and communication unit monitors the working status and parameters of the entire module. While completing the local oscillator frequency configuration and lock monitoring, the temperature and power monitoring parameters are simultaneously uploaded to the interference monitoring and direction finding software through the external communication interface; The signal processing module adopts the form of ADC+FPGA+DSP. The ADC performs analog-to-digital conversion on the signal to obtain sampling data; the FPGA completes multi-channel combination processing of sampling data, spectrum FFT processing of monitoring, DDC filtering extraction processing of direction finding, array element direction finding data combination accumulation processing, spectrum parameter estimation, direction finding parameter estimation and comprehensive control processing; the DSP completes direction finding signal sorting, signal format identification, and realizes integrated direction finding of the signal to be measured by comprehensively utilizing spatial spectrum direction finding algorithm, interferometer direction finding algorithm and multi-beam direction finding algorithm, and completes the reporting of monitoring and direction finding data and the forwarding of comprehensive control commands at the same time; the signal processing module has a 5-channel 16-bit high-speed ADC, FPGA and DSP signal processing resources, and an external clock input to provide a clock for signal processing; it has GPIO to realize the control of peripherals such as radio frequency, and communicates with an external computer through a 100M network.

[0025] The main control module consists of a core processing unit (embedded computer), a power monitoring and control unit, a temperature and humidity monitoring unit, an abnormal warning processing unit, a parameter storage unit, a data transmission unit and a power supply unit. The core processing unit consists of an ARM processor and peripheral circuits. It is mainly used for monitoring and controlling each functional unit, driving the alarm unit, and is responsible for the analysis, processing, packaging and sending of interference monitoring data. It is the computing and processing core of the equipment management unit.

[0026] The power module is the core device that provides energy for the monitoring and direction finding host. The module can convert the external 24VAC AC power supply into a DC 12V power supply and send it to each module through the motherboard branch. The power module mainly provides power for the entire monitoring and direction finding host. It can convert +24V DC power into +12V, +5V, etc. to power the various functional units in the monitoring and direction finding host and the monitoring and direction finding antenna outside the monitoring and direction finding host. The power supply of the monitoring and direction finding antenna mainly adopts the bundled cable feeding method.

[0027] The interference monitoring and direction finding software mainly manages and controls the monitoring terminal, and realizes the functions of receiving and storing monitoring data, analyzing and processing, data forwarding, data visualization, and equipment management. The software is embedded in the main control module of the monitoring and direction finding host, and can display the vehicle-mounted GNSS multi-interference monitoring and direction finding results and equipment working conditions in real time. It can also send control instructions to the monitoring and direction finding host to start the monitoring and direction finding antenna to monitor the receiving interference signal.

[0028] The interference monitoring and direction-finding software mainly includes interference monitoring module, data receiving and parsing module, parameter setting module, data playback and storage module, display control module, etc. Among them, 1) the interference monitoring module is mainly used to display real-time monitoring data, including signal spectrum, characteristic parameters and other monitoring results; 2) the data receiving and parsing module can be used to receive interference monitoring data information, Beidou / GNSS monitoring data information and working condition information collected and processed by the equipment, and parse and process these data according to the protocol, and transmit the information to be displayed to the display control module; 3) the parameter setting module is mainly used to set the local parameters of the monitoring and direction-finding software; 4) the data playback and storage module can query, playback and store the monitoring data under the specified scanning mode and time period.

[0029] The monitoring and direction-finding device was mounted on a vehicle-mounted platform for testing and verification: first, four fixed suppression interference sources were set up 5 meters away from the device at 0°, 30°, 90°, and 270° in the north direction, and the same-frequency interference signals with a frequency of 1268.52 MHz were emitted; then the vehicle-mounted GNSS multi-interference source monitoring and direction-finding device was started to perform spectrum monitoring of the electromagnetic environment around the vehicle; finally, the monitoring and direction-finding results displayed by the interference monitoring and direction-finding software were compared with the actual position and direction. It can be seen from the monitoring results that all four interference signals were monitored, and the direction-finding pointers of the four same-frequency suppression interference sources displayed on the direction-finding software interface were roughly the same as the actual position and direction, the direction-finding error was kept within 3°, and the direction-finding results were relatively stable without any fluctuations. The interference monitoring and direction-finding results of the device are shown in Figure 2. Figure 4 shown.

[0030] like Figure 5 As shown, this embodiment also discloses a monitoring direction finding method, using the above-mentioned monitoring direction finding device: The antenna unit receives electromagnetic waves radiated in 360° space with equal spacing, and transmits them to the back-end multi-channel switch and amplification circuit; the switch matrix controls the selection of channels to output the signals transmitted by the antenna unit to different RF output terminals; the electronic compass measures the antenna attitude in real time and outputs it to the antenna controller in real time; the antenna controller controls the channel selection of the switch matrix according to the instructions, and collects the electronic compass information and transmits it to the monitoring and direction finding host; The RF receiving module is responsible for receiving the interference signal received by the monitoring and direction-finding antenna. The receiving channel is five channels. After low-noise amplification and pre-selection, superheterodyne mixing is performed and converted into an intermediate frequency signal for output to the signal processing module. The signal processing module receives the intermediate frequency signal output by the RF receiving module, and after analog-to-digital conversion, it processes and calculates to realize the monitoring of abnormal signals in the frequency band, signal analysis, direction finding and weak spread spectrum signal detection; the main control module controls each module to complete function initialization, receiver control, data analysis, data processing, data packaging, auxiliary underlying operations and data storage and transmission; the service performance monitoring algorithm is used to analyze and process to obtain the Beidou service performance monitoring results, and the interference monitoring direction-finding algorithm is used to analyze and process to obtain the interference monitoring direction-finding results, and the direction-finding results are stored locally; in addition, the main control module can also receive control instructions such as monitoring mode and storage strategy issued by the upper node, and transmit interference monitoring data and interference direction-finding data to the upper node.

Claims

1. A vehicle-mounted GNSS multi-interference source monitoring and direction finding device, characterized in that: The monitoring direction-finding device comprises a monitoring direction-finding antenna and a monitoring direction-finding host. The monitoring direction-finding antenna comprises an antenna unit, a switch matrix, an electronic compass and an antenna controller, wherein the antenna unit is electrically connected to the switch matrix, and the switch matrix and the electronic compass are electrically connected to the antenna controller respectively; the monitoring direction-finding host comprises a radio frequency receiving module, a signal processing module, a main control module and a power supply module, wherein the input end of the radio frequency receiving module is connected and communicated with the antenna controller, and the output end is electrically connected to the main control module through the signal processing module, and the power supply module supplies power to the monitoring direction-finding antenna and the monitoring direction-finding host.

2. The vehicle-mounted GNSS multi-interference source monitoring and direction finding device according to claim 1 is characterized in that: The antenna unit adopts a uniformly distributed multi-element antenna array, and the antenna array element adopts a planar printed circuit board broadband dipole antenna.

3. The vehicle-mounted GNSS multi-interference source monitoring and direction finding device according to claim 1, characterized in that: The switch matrix includes multi-channel switches and small signal amplifiers.

4. The vehicle-mounted GNSS multi-interference source monitoring and direction finding device according to claim 1, characterized in that: The electronic compass is a high-precision three-dimensional digital compass that uses high-precision magnetoresistive sensors and inertial devices.

5. The vehicle-mounted GNSS multi-interference source monitoring and direction finding device according to claim 1, characterized in that: The control circuit of the antenna controller adopts FPGA.

6. The vehicle-mounted GNSS multi-interference source monitoring and direction finding device according to claim 1, characterized in that: The RF receiving module is an independent shell structure. Inside the RF receiving module, the external input signal is filtered by a segmented filter and then frequency-converted with the local oscillator 1 signal from the local oscillator unit to generate a first intermediate frequency signal. The signal is then filtered and amplified and mixed with the local oscillator 2 signal. The mixed signal is transmitted to the intermediate frequency unit and the intermediate frequency signal is obtained after multi-stage "filtering + attenuation + amplification + filtering" processing.

7. The vehicle-mounted GNSS multi-interference source monitoring and direction finding device according to claim 1, characterized in that: The signal processing module adopts the form of ADC+FPGA+DSP. The ADC performs analog-to-digital conversion on the signal to obtain sampling data; the FPGA completes multi-channel combination processing of sampling data, spectrum FFT processing of monitoring, DDC filtering extraction processing of direction finding, array element direction finding data combination accumulation processing, spectrum parameter estimation, direction finding parameter estimation and comprehensive control processing; the DSP completes direction finding signal sorting, signal format identification, and realizes integrated direction finding of the signal to be measured by comprehensively utilizing spatial spectrum direction finding algorithm, interferometer direction finding algorithm and multi-beam direction finding algorithm, and completes the reporting of monitoring and direction finding data and the forwarding of comprehensive control commands; it also has external clock input to provide clock for signal processing; it has GPIO to realize peripheral control and communicate with external computers through 100M network.

8. The vehicle-mounted GNSS multi-interference source monitoring and direction finding device according to claim 1, characterized in that: The main control module consists of a core processing unit, a power monitoring and control unit, a temperature and humidity monitoring unit, an abnormal warning processing unit, a parameter storage unit, a data transmission unit and a power supply unit. The core processing unit consists of an ARM processor and peripheral circuits.

9. A monitoring direction finding method, using the monitoring direction finding device according to claim 1, characterized in that: The antenna unit receives electromagnetic waves radiated in 360° space with equal spacing, and transmits them to the back-end multi-channel switch and amplification circuit; the switch matrix controls the selection of channels to output the signals transmitted by the antenna unit to different RF output terminals; the electronic compass measures the antenna attitude in real time and outputs it to the antenna controller in real time; the antenna controller controls the channel selection of the switch matrix according to the instructions, and collects the electronic compass information and transmits it to the monitoring and direction finding host; The RF receiving module is responsible for receiving the interference signal received by the monitoring and direction-finding antenna. The receiving channel is five channels. After low-noise amplification and pre-selection, superheterodyne mixing is performed and converted into an intermediate frequency signal to be output to the signal processing module. The signal processing module receives the intermediate frequency signal output by the RF receiving module, and after analog-to-digital conversion, it processes and calculates to realize the monitoring of abnormal signals in the frequency band, signal analysis, direction finding and weak spread spectrum signal detection; the main control module controls each module to complete function initialization, receiver control, data analysis, data processing, data packaging, auxiliary underlying calculation and data storage and transmission; the service performance monitoring algorithm is used to analyze and process to obtain the Beidou service performance monitoring results, and the interference monitoring direction-finding algorithm is used to analyze and process to obtain the interference monitoring direction-finding results, and the direction-finding results are stored locally; In addition, the main control module can also receive the monitoring mode and storage strategy sent by the upper node, and transmit interference monitoring data and interference direction finding data to the upper node.

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