CN111537806A - On-spot metering device of ocean ground wave radar electromagnetic signal - Google Patents
On-spot metering device of ocean ground wave radar electromagnetic signal Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention discloses a marine ground wave radar electromagnetic signal field metering device. The device includes: the device comprises a standard signal transmitting unit, a standard gain antenna, a shell, a comprehensive data processing system, a broadband receiving unit, an antenna biasing unit and a rechargeable built-in battery, wherein the comprehensive data processing system, the broadband receiving unit, the antenna biasing unit and the rechargeable built-in battery are arranged in the shell; the standard signal transmitting unit comprises a positioning module, a special DDS chip for generating a standard fixed frequency signal and a transmitting antenna connected with a signal output end of the DDS chip; the ground wave radar antenna receives a signal sent by a transmitting antenna of the standard signal transmitting unit; the standard gain antenna is used for receiving wireless electromagnetic signals transmitted by the ground wave radar; the broadband receiving unit comprises a radio frequency and signal processing circuit for extracting the frequency spectrum characteristics of the input signal; the comprehensive data processing system is connected with the output end of the radio frequency and signal processing circuit. The invention has the characteristic of high integration level and can support long-time continuous measurement and real-time signal processing.
Description
Technical Field
The invention relates to the technical field of ocean monitoring, in particular to an electromagnetic signal field metering device for an ocean ground wave radar.
Background
As a new ocean monitoring technology, the high-frequency ground wave radar has the advantages of over-the-horizon, large range, all weather, low cost and the like, and is considered to be a high-tech means capable of effectively monitoring exclusive economic areas of all countries. The ground wave radar is a novel ocean observation technology for measuring sea surface flow field, wave field, wind field and other elements according to radar backward Bragg scattering signals by utilizing the characteristic that high-frequency electromagnetic waves are small in diffraction propagation attenuation along the surface of seawater. The ground wave radar can provide a refined sea surface flow field for offshore disaster prevention and reduction, offshore oil spill, offshore search and rescue, airway guarantee and the like, and is one of the most favorable observation means for offshore marine environment guarantee at the present stage.
As a remote measuring means of field electromagnetic signals, the field electromagnetic environment acting on the electromagnetic signals can cause field intensity change, antenna directional diagram distortion and the like, the current measuring range and the observation precision of the ground wave radar are directly influenced, meanwhile, the drift of key radio parameters such as observation frequency, power, bandwidth and the like can influence the flow field observation spatial resolution, interference is generated on surrounding radio equipment, and adverse social influence is caused. Therefore, in order to ensure the accuracy of high-frequency ground wave radar current measurement and support the radio management work of the ground wave radar, the measurement, inspection and calibration of key radio parameters of the ground wave radar equipment are required to be carried out regularly.
At present, a discrete universal instrument is generally adopted for field measurement of electromagnetic signals of a ground wave radar, and the system integration level is not high; the electromagnetic environment of the ground wave radar working is greatly different at different time and in different seasons, and needs long-time continuous observation, and because the ground wave radar is usually installed at the sea, the existing instrument can not meet the requirement of long-time observation of the ground wave radar on site; the ground wave radar antenna directional diagram is one of the important factors influencing sea state element measurement, is greatly influenced by the surrounding environment (such as buildings, metal facilities and the like), and has higher difficulty when the existing discrete equipment cannot finish the measurement or measurement of the parameters. The field electromagnetic environment of the ground wave radar is very complex, so that not only the signal of the working frequency of the radar itself exists, but also a plurality of electromagnetic signals of other frequency bands exist, and certain difficulty is brought to the measurement of the field intensity parameter of the electromagnetic signal. At present, the field intensity measurement is completed by adopting a field intensity meter, but the field intensity meter measures all frequency band electromagnetic signals in a measured frequency range and then provides composite field intensity, but not field intensity of a certain specific frequency band or frequency point, so that the method cannot meet the field intensity measurement of important indexes such as useful signals, interference signals, environmental noise and the like in a radar working frequency band, and cannot meet the use requirement under the radar working environment. The existing equipment has no real-time property for processing and analyzing the measured data, cannot process signals by adopting a time-frequency analysis method, and lacks functions of automatic recording and processing of data and the like.
Disclosure of Invention
The invention aims to provide an electromagnetic signal field metering device for an ocean ground wave radar, which has the characteristic of high integration level and can support long-time continuous measurement and real-time signal processing.
In order to achieve the purpose, the invention provides the following scheme:
an ocean ground wave radar electromagnetic signal field metering device, comprising: the device comprises a standard signal transmitting unit, a standard gain antenna, a shell, a comprehensive data processing system, a broadband receiving unit, an antenna biasing unit and a rechargeable built-in battery, wherein the comprehensive data processing system, the broadband receiving unit, the antenna biasing unit and the rechargeable built-in battery are arranged in the shell;
the standard signal transmitting unit comprises a positioning module, a special DDS chip for generating a standard fixed frequency signal and a transmitting antenna connected with the signal output end of the DDS chip; the ground wave radar antenna receives the signal sent by the transmitting antenna of the standard signal transmitting unit;
the standard gain antenna is used for receiving wireless electromagnetic signals transmitted by a ground wave radar, and the shape structure and the polarization mode of the standard gain antenna are consistent with those of a ground wave radar transmitting antenna;
the broadband receiving unit comprises a radio frequency and signal processing circuit, and the radio frequency and signal processing circuit is used for extracting the frequency spectrum characteristics of the input signal;
the comprehensive data processing system is connected with the output end of the radio frequency and signal processing circuit;
when measuring the frequency, the bandwidth, the frequency band to be measured and the field intensity at the frequency point of the signal, connecting the input end of the radio frequency and signal processing circuit with the output end of the standard gain antenna through the antenna biasing unit, and determining the frequency, the bandwidth, the field intensity at the frequency band to be measured and the frequency point of the input signal by the comprehensive data processing system according to the frequency spectrum characteristic signal output by the radio frequency and signal processing circuit; when an antenna directional diagram of the ground wave radar is measured, the input end of the radio frequency and signal processing circuit is connected with the output end of a receiving antenna of the ground wave radar through the antenna biasing unit, and the comprehensive data processing system determines the antenna directional diagram of the ground wave radar according to the frequency spectrum characteristic signal output by the radio frequency and signal processing circuit and the position information provided by the positioning module;
the rechargeable built-in battery is used for supplying power to the broadband receiving unit, the integrated data processing system and the antenna biasing unit.
Optionally, the metering device further includes: the device comprises a bidirectional coupler and an attenuator, wherein when the transmitting power of a ground wave radar transmitter is measured, the bidirectional coupler is installed between the ground wave radar transmitter and a ground wave radar transmitting antenna, the input end of the attenuator is connected with the coupling output end of the bidirectional coupler, and the output end of the attenuator is connected with the input end of the radio frequency and signal processing circuit.
Optionally, the isolation of the bidirectional coupler is not lower than 30 dB.
Optionally, the radio frequency and signal processing circuit includes: the system comprises a radio frequency signal processing subunit, an FPGA-based digital signal processing subunit and a microprocessor, wherein the microprocessor is used for controlling the processing process of the FPGA; and the input signal of the radio frequency and signal processing circuit is output after sequentially passing through the radio frequency signal processing subunit and the digital signal processing subunit.
Optionally, the radio frequency signal processing subunit includes: local oscillator, radio frequency input attenuator, low pass filter, amplifier, mixer, band pass filter and analog-to-digital converter, input signal pass through in proper order the radio frequency input attenuator low pass filter the amplifier gets into the mixer, the local oscillator signal warp that local oscillator sent the amplifier gets into the mixer, the signal of mixing output passes through behind the band pass filter, obtains the difference frequency signal, the difference frequency signal warp the output behind the analog-to-digital converter.
Optionally, the digital signal processing subunit based on the FPGA includes: the digital down-conversion module comprises a multiplier and a direct digital synthesizer, and signals output by the analog-to-digital converter sequentially pass through the digital down-conversion module, the low-pass filtering module, the speed reduction extraction module and the frequency spectrum calculation module and are output.
Optionally, the standard signal transmitting unit further includes: the system comprises a processor, a power supply module, a data transmission radio and an antenna; the processor receives external input parameters through a UART interface, forms control parameters of the DDS chip through analysis and processing, and writes the control parameters into the DDS chip through an SPI; the processor is also used for extracting the position information received by the positioning module and transmitting the position information to the comprehensive data processing system through the data transmission radio station and the antenna; and the power supply module supplies power to the standard signal transmitting unit.
Optionally, the integrated data processing system includes a data transmission module, a data processing and analyzing module and a display and control module, the data transmission module is used for completing data transmission, the data processing and analyzing module is used for completing analysis and storage of the spectrum characteristic signal, and the display and control module is used for displaying the measured data, displaying the human-computer interaction interface and providing input of device parameters, device measurement parameters and instructions.
Optionally, a handle and a travelling wheel are arranged on the shell.
Optionally, a power supply interface of the integrated data processing system, a charging interface of the rechargeable internal battery, and a data transmission interface of the broadband receiving unit are arranged on the top surface of the housing.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects: the device integrates a standard signal transmitting unit, a standard gain antenna, a comprehensive data processing system and a broadband receiving unit, wherein the standard signal transmitting unit can transmit continuous signals with set frequency and longitude and latitude information of the position, and can be matched with the broadband receiving unit and the comprehensive data processing system for use, so that the field measurement of a ground wave radar antenna directional diagram can be completed. The standard gain antenna is used for receiving wireless electromagnetic signals, the radio frequency and signal processing circuit extracts the frequency spectrum characteristics of the ground wave radar electromagnetic signals, and the frequency and bandwidth characteristics of the radar wireless electromagnetic signals can be obtained in real time in cooperation with the analysis and processing of the comprehensive data processing system. The field intensity measurement of the frequency band to be measured and the frequency point can be completed by the matching use of the standard gain antenna, the antenna bias unit, the radio frequency and signal processing circuit and the comprehensive data processing system. The measurement of the transmitting power of the ground wave radar can be completed by the matching use of the radio frequency and signal processing circuit, the bidirectional coupler, the attenuator and the comprehensive data processing system. Therefore, the method and the device realize real-time measurement of the key electrical parameters of the electromagnetic signals of the ocean ground wave radar. Moreover, the metering device provided by the invention is provided with a high-capacity rechargeable built-in battery, and can support long-time continuous measurement.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic diagram of a basic structure of an electromagnetic signal field metering device of an ocean ground wave radar in an embodiment of the invention;
FIG. 2 is a schematic diagram of a radar transmission power measurement in an embodiment of the present invention;
FIG. 3 is a front view of the internal structure of the housing in an embodiment of the present invention;
FIG. 4 is a side view of the internal structure of the housing in an embodiment of the present invention;
FIG. 5 is a schematic diagram of an RF and signal processing circuit according to an embodiment of the present invention;
FIG. 6 is a functional block diagram of a down conversion module in an embodiment of the present invention;
FIG. 7 is a block diagram of a standard signal transmitting unit according to an embodiment of the present invention;
FIG. 8 is a software architecture diagram of an integrated data processing system in an embodiment of the present invention.
1. The bottom layer is fixed with an aluminum plate; 2. a radiator fan fixing support; 3. the middle layer is fixed with an aluminum plate; 4. an aluminum plate is fixed on the upper layer; 5. an antenna biasing unit; 6. installing a slot position of the integrated data processing system; 7. a standard gain antenna; 8. an antenna radio frequency connector; 9. a housing; 10. a high-capacity rechargeable built-in battery; 11. a heat radiation fan; 12. a comprehensive data processing system power supply interface; 13. a built-in battery charging interface; 14. a built-in battery charging state display screen; 15. a key switch; 16. big dipper/GPS location antenna.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
The invention provides a marine ground wave radar electromagnetic signal field metering device, which comprises: the device comprises a standard signal transmitting unit, a standard gain antenna, a shell, a comprehensive data processing system, a broadband receiving unit, an antenna biasing unit and a rechargeable built-in battery, wherein the comprehensive data processing system, the broadband receiving unit, the antenna biasing unit and the rechargeable built-in battery are arranged in the shell;
the standard signal transmitting unit comprises a positioning module, a special DDS chip for generating standard fixed frequency signals and a transmitting antenna connected with the signal output end of the DDS chip, wherein electromagnetic signals sent by the transmitting antenna are received by a ground wave radar antenna;
the standard gain antenna is used for receiving wireless electromagnetic signals transmitted by a ground wave radar, and the shape structure and the polarization mode of the standard gain antenna are consistent with those of a ground wave radar transmitting antenna; the standard gain antenna can adopt a whip antenna which is consistent with the shape structure and the polarization mode of a ground wave radar transmitting antenna, the antenna has a wider frequency band range and a lower standing-wave ratio, and important indexes such as an antenna directional diagram, gain and the like of the antenna are calibrated to ensure the accuracy of the device for measuring the wireless electromagnetic signals;
the broadband receiving unit comprises a radio frequency and signal processing circuit, and the radio frequency and signal processing circuit is used for extracting the frequency spectrum characteristics of the input signal;
as shown in fig. 1, the integrated data processing system is connected to the output of the broadband receiving unit.
When measuring the frequency, the bandwidth, the frequency band to be measured and the field intensity at the frequency point of the signal, the input end of the radio frequency and signal processing circuit is connected with the output end of the standard gain antenna through the antenna biasing unit, and at this time, the comprehensive data processing system determines the frequency, the bandwidth, the frequency band to be measured and the field intensity at the frequency point of the input signal according to the frequency spectrum characteristic signal output by the radio frequency and signal processing circuit. In this embodiment, the radio frequency and signal processing circuit may obtain the power value of each frequency point in the frequency band to be measured by extracting the frequency spectrum characteristic of the wireless electromagnetic signal, and since the standard gain antenna has a constant and known antenna factor in the ground wave radar operating frequency band, the field strength value of the frequency point to be measured may be calculated according to the definition formula of the antenna factor.
When an antenna directional diagram of the ground wave radar is measured, the input end of the radio frequency and signal processing circuit is connected with the output end of the ground wave radar antenna, and the comprehensive data processing system determines the antenna directional diagram of the ground wave radar according to the frequency spectrum characteristic signal output by the radio frequency and signal processing circuit and the position information provided by the standard signal transmitting unit positioning module.
The rechargeable built-in battery is used for supplying power to the broadband receiving unit, the integrated data processing system and the antenna biasing unit.
On the basis of the above embodiment, the metering device in this embodiment further includes: and when the transmitting power of the ground wave radar transmitter is measured, as shown in fig. 2, the two-way coupler is installed between the ground wave radar transmitter and the ground wave radar transmitting antenna, the input end of the attenuator is connected with the coupling output end of the two-way coupler, and the output end of the attenuator is connected with the input end of the radio frequency and signal processing circuit.
As an optional implementation manner, the bidirectional coupler may be a bidirectional coupler with an isolation degree not lower than 30 dB.
The metering device provided by the invention mainly comprises a broadband receiving unit, a standard gain antenna, a comprehensive data processing system and a standard signal transmitting unit, wherein the first three units form the main body part of the metering device, and the standard signal transmitting unit is matched with the main body part of the metering device for use, so that the field metering of an antenna directional diagram can be completed. The broadband receiving unit measures the ground wave radar electromagnetic signals based on a spectrum analysis method, and obtains the frequency and bandwidth characteristics of the radar wireless electromagnetic signals in real time. By using the coupler and the attenuator, the broadband receiving unit can complete the field measurement of the transmitting power of the radar transmitter on site; by using the standard gain antenna, the broadband receiving unit can complete the field intensity measurement of the frequency band to be measured and the frequency point; the standard signal transmitting unit can transmit continuous signals with set frequency and longitude and latitude information of the position, and the measuring device can complete measurement of a radar antenna directional diagram on site by combining with a main body part of the measuring device. The measurement results are processed, displayed, analyzed and stored by the comprehensive data processing system in real time. The main body part of the metering device is internally provided with a large-capacity rechargeable battery, and the metering device is suitable for long-time automatic observation in the field. By using the field measurement data of the metering device to calibrate the ocean ground wave radar, the measurement precision of the radar can be improved, and the effective and real-time management on the working state of the ocean ground wave radar can be realized.
It should be emphasized that, in the above embodiments, when the integrated data processing system determines the frequency, the bandwidth, the field strength, the directional diagram of the signal and the transmitting power of the radar transmitter according to the spectrum characteristic signal output by the radio frequency and signal processing circuit, the specific method or the specific software module adopted is a conventional method or module in the art, and the present invention is not specifically described again, and it does not belong to the claimed content of the present invention.
In the above embodiment, as shown in fig. 3 and 4, the housing 9 may be designed to have a layered structure of 3 layers, the lowest layer may be mounted with the high-capacity rechargeable internal battery 10, and the middle layer may be mounted with the rf and signal processing circuit board and reserves a mounting position for the antenna bias unit 5, so as to facilitate the assembly and disassembly of the unit; the uppermost layer may be provided with an integrated data processing system installation slot 6, such as an installation slot of a notebook computer in which the supporting data processing software is installed. And 2 groups of heat radiation fans 11 can be arranged at the lowest layer. 5 switch keys 15 can be arranged for respectively supplying power to a system starting unit, a broadband receiving unit, an antenna bias unit, a comprehensive data processing system and a cooling fan switch, and the switch form adopts a self-locking switch with indications such as an LED and the like. A power supply interface 12 of the comprehensive data processing system, a charging interface 13 of the built-in battery and a data transmission interface of the circuit board can be arranged on the top panel, so that the data cross-linking and power supply between the system and external equipment are facilitated. The shell body is made of firm, durable and light plastic materials, can be provided with walking wheels and handles, and is convenient to transport in the field environment.
The wideband receiving unit in the above embodiment utilizes the basic idea of spectrum analysis, and adopts a superheterodyne structure to extract the spectrum feature of the electromagnetic signal. The radio frequency and signal processing circuitry may include: the system comprises a radio frequency signal processing subunit, an FPGA-based digital signal processing subunit and a microprocessor, wherein the microprocessor is used for controlling the processing process of the FPGA; and the input signal of the radio frequency and signal processing circuit is output after sequentially passing through the radio frequency signal processing subunit and the digital signal processing subunit. High-frequency ground wave radar electromagnetic signals enter the broadband receiving unit through the ground wave radar antenna or the standard gain antenna, and the upper limit of the frequency in a signal path is limited to 100MHz by using a low-pass filter. The local oscillator signal and the low-pass filtering output signal are amplified by using an amplifier to be in accordance with the signal input range of the frequency mixer, the result after frequency mixing output is filtered out of a sum frequency signal after band-pass filtering, and the difference frequency signal is reserved. And performing analog-to-digital conversion on the digital signal, finishing the processing of the sampled digital signal by the FPGA and the ARM, and transmitting the processed result to the comprehensive data processing system.
As shown in fig. 5, the radio frequency signal processing subunit may include: local oscillator, radio frequency input attenuator, low pass filter, amplifier, mixer, band pass filter and analog-to-digital converter, input signal pass through in proper order the radio frequency input attenuator low pass filter the amplifier gets into the mixer, the local oscillator signal warp that local oscillator sent the amplifier gets into the mixer, the signal of mixing output passes through behind the band pass filter, obtains the difference frequency signal, the difference frequency signal warp the output behind the analog-to-digital converter. The FPGA-based digital signal processing subunit may include: the digital down-conversion module comprises a multiplier and a direct digital synthesizer, and signals output by the analog-to-digital converter sequentially pass through the digital down-conversion module, the low-pass filtering module, the speed reduction extraction module and the frequency spectrum calculation module and are output.
The design of each device in the radio frequency signal processing subunit can be selected as follows:
in order to ensure that the amplitude of the input signal of the mixer meets the input requirement, a chip AD8009 manufactured by ADI corporation can be used as the front-end amplifying circuit of the mixer, and the chip is an ultra-high speed current feedback type amplifier and is suitable for amplifying the local oscillation signal to meet the mixing voltage of the multiplier. Meanwhile, the voltage bias can be carried out on the baseband signal, and the sampling requirement of a rear-stage ADC is facilitated. The input stage is impedance matched when the circuit is designed.
The local oscillator can adopt a DDS special chip AD9958 manufactured by ADI company, which is a DDS device manufactured by analog devices company, which has high performance, excellent dynamic characteristics and double-path output, and each path can independently control the frequency, the phase and the amplitude. The chip can generate two-way signals with the highest frequency of 250 MHz. Inside which a number of control registers for controlling parameters of the output signal are located. When the system finishes measurement in a frequency band of 3-50MHz, a local oscillation signal generated by the AD9958 needs to be controlled. The frequency, phase and amplitude of the local oscillator signals are related to the corresponding control words of the AD 9958. According to the basic principle of superheterodyne, a linear scanning mode is adopted in design. The ARM chip is adopted as a system main control chip, the data content of serial cache can be sent to an AD9958 internal register through the programming of the chip, and a local oscillation signal is output, so that frequency sweeping is realized.
An AD835 chip is used as a mixer, the AD835 chip is an analog multiplier for outputting 250MHz four-quadrant voltage, the product noise is only 50nV/Hz, and the function of outputting W-X-Y + Z signals can be completed. Since the filter with a lower operating frequency is easier to implement, the difference frequency signal of the mixing output is extracted. Impedance matching is performed at the input and output stages during design to avoid voltage reflections. The local oscillation signal and the input signal are respectively connected with X1 and Y1 channels of the mixer, the input impedance and the output impedance are both 50 omega, the input voltage range is-1 to +1V, and the bandwidth is 40 MHz.
The AD sampling adopts an AD9244 chip which is an analog-digital converter with 14 bit sampling digits and the number of sampling points per second can reach 40Msps when the power consumption is 300 mW. In the design, the AD9244 samples the analog input signal by using a sampling rate of 40MHz, and the technical index of the chip meets the design requirement.
The design of each module in the digital signal processing subunit based on the FPGA is selected as follows:
as shown in fig. 6, the digital down-conversion module consists of a multiplier and a direct digital synthesizer. The carrier frequency of the intermediate frequency signal processed by the radio frequency front end is 10MHz, the signal is subjected to down-conversion after being sampled by 40MHz, a Direct Digital Synthesizer (DDS) in an IP core is called in the FPGA to generate a sinusoidal signal with the frequency of 9.8MHz as a local oscillation signal, and the two signals are subjected to frequency mixing to obtain signals with the carrier frequencies of 200kHz and 19.8 MHz.
And the low-pass filtering module filters the signal with the center frequency of 19.8MHz after down-conversion by using a low-pass filter and reserves the signal of 200kHz according to the requirement of a subsequent algorithm. The filter adopts an FIR form, and the cut-off frequency of the passband and the starting frequency of the stopband are determined by combining with measured data on the premise of ensuring that the order of the filter is smaller during design.
The speed-reducing extraction module needs to perform a series of digital signal processing on the signal output by the low-pass filtering, and an excessively high sampling rate affects the performance of subsequent signal processing and occupies excessive resources, so that the speed-reducing processing needs to be performed on the filtered signal. The signal is resampled here with a sampling rate of 400 kHz.
Let the original sampling sequence be x (n), and extract one data (double extraction) every D-1 data to form a new sequence x1(m), namely:
x1(m) ═ x (Dm) (m, D are integers)
The low pass filtered signal is decimated to reduce the data rate from 40MSps to a suitable level. Because the bandwidth of the electromagnetic signal of the ground wave radar is less than 150kHz, in order to improve the real-time performance and reduce the computation amount of subsequent signal processing, based on the Nyquist sampling theorem, the sampling rate of 400kHz is used for speed reduction extraction, namely D in the above formula is 400, and the data rate is reduced to 400 kSps.
The spectrum calculation module utilizes an IP core in the FPGA to complete Fast Fourier Transform (FFT) of a digital signal, the selected FPGA can complete the FFT of 65536 points at one time, and the signal sampling rate is reduced to 400kHz after speed reduction and extraction, so that the processing requirement of the FFT can be met. The signal after FFT is processed by envelope detection and transmitted to the integrated data processing system through the LAN transmission line. The frequency is taken as a horizontal component, the vertical axis displays the signal amplitude, and a spectrogram of an input signal is drawn on a screen of the system.
The broadband receiving unit adopts a radio frequency circuit, a digital circuit and a microprocessor framework inside and has the functions of storage and operation; and a standard interface is configured to be used as an important component of the metering device to complete the measurement of the wireless electromagnetic signal.
In practical applications, the standard signal transmitting unit may further include: the device comprises a processor, a power supply module, a data transmission radio and an antenna. The standard signal transmitting unit can transmit a fixed-frequency continuous signal and current position information, the working frequency is 3-50MHz, the standard signal transmitting unit has a GNSS positioning function and an embedded system. As shown in fig. 7, the positioning module can receive GPS and Beidou signals, the horizontal positioning accuracy is better than 10 meters, and the latitude and longitude information is extracted and processed by the ARM processor and then transmitted by the antenna of the data radio. The processor receives external input parameters through the UART interface, control parameters of the DDS chip are formed through analysis and processing, the control parameters are written into the DDS chip through the SPI, the DDS chip generates standard fixed frequency signals according to the control parameters, the output of the DDS chip is filtered out of band stray signals through the band-pass filter, and the signals are transmitted out through the transmitting antenna after power amplification. The transmitting antenna adopts a high-gain omnidirectional antenna in a frequency band of the ground wave radar, so that the reliable transmission of signals is ensured. And the power supply module supplies power to the standard signal transmitting unit.
As shown in FIG. 8, the integrated data processing system may include a data transmission module, a data processing analysis module, and a display and control module. The data transmission module is responsible for controlling data communication between each measurement unit of the software and the computer and communication between the measurement system and other equipment; the method comprises the steps of packaging and unpacking of measurement data and a control command protocol, inputting data of a radar and signal transmitting unit and the like. In order to ensure the high reliability of the data transmission module and ensure that the measured data is not lost, an independent process mode is adopted and the background operation is carried out. And the data processing and analyzing module is used for finishing the calculation of measurement elements such as field intensity values and the like according to the equipment parameters and the measurement data, automatically analyzing the signal characteristics and storing the measurement results. And finishing the calculation of the antenna directional diagram according to the measurement data, the positioning data, the radar data and the like. The display and control module provides a man-machine interaction interface of the measuring system and provides input of equipment parameters, equipment measuring parameters and instructions; displaying measurement data such as frequency, power, bandwidth, field intensity and the like in real time; the frequency spectrum can be displayed, and a frequency spectrum waterfall graph can be displayed.
The ground wave radar electromagnetic signal field metering device provided by the invention has the following advantages:
1. the built-in high-capacity rechargeable battery can support the device to continuously measure for 24 hours, meet the long-time continuous observation requirement and is suitable for carrying out long-term unattended observation on the ground wave radar and the electromagnetic environment around the ground wave radar at different times and different seasons;
2. the system integration level is high, the measurement indexes are diversified, the system can be remotely set according to the field environment during measurement, and the operation is simple and convenient;
3. the directional diagram of the ground wave radar antenna can be measured on site, and the calibrated ground wave radar can improve the measurement precision of sea state elements;
4. the method can measure the composite field intensity of the working frequency band of the ground wave radar or the field intensity of a certain specific frequency point, so that the measurement of environmental noise and the measurement of the field intensity of radar signals and interference signals are ensured.
5. The real-time measurement and data analysis of the electromagnetic signals of the ground wave radar can be completed on site.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (10)
1. The utility model provides an on-spot metering device of ocean ground wave radar electromagnetic signal which characterized in that includes: the device comprises a standard signal transmitting unit, a standard gain antenna, a shell, a comprehensive data processing system, a broadband receiving unit, an antenna biasing unit and a rechargeable built-in battery, wherein the comprehensive data processing system, the broadband receiving unit, the antenna biasing unit and the rechargeable built-in battery are arranged in the shell;
the standard signal transmitting unit comprises a positioning module, a special DDS chip for generating a standard fixed frequency signal and a transmitting antenna connected with the signal output end of the DDS chip; the ground wave radar antenna receives the signal sent by the transmitting antenna of the standard signal transmitting unit;
the standard gain antenna is used for receiving wireless electromagnetic signals transmitted by a ground wave radar, and the shape structure and the polarization mode of the standard gain antenna are consistent with those of a ground wave radar transmitting antenna;
the broadband receiving unit comprises a radio frequency and signal processing circuit, and the radio frequency and signal processing circuit is used for extracting the frequency spectrum characteristics of the input signal;
the comprehensive data processing system is connected with the output end of the radio frequency and signal processing circuit;
when measuring the frequency, the bandwidth, the frequency band to be measured and the field intensity at the frequency point of the signal, connecting the input end of the radio frequency and signal processing circuit with the output end of the standard gain antenna through the antenna biasing unit, and determining the frequency, the bandwidth, the field intensity at the frequency band to be measured and the frequency point of the input signal by the comprehensive data processing system according to the frequency spectrum characteristic signal output by the radio frequency and signal processing circuit; when an antenna directional diagram of the ground wave radar is measured, the input end of the radio frequency and signal processing circuit is connected with the output end of a receiving antenna of the ground wave radar through the antenna biasing unit, and the comprehensive data processing system determines the antenna directional diagram of the ground wave radar according to the frequency spectrum characteristic signal output by the radio frequency and signal processing circuit and the position information provided by the positioning module;
the rechargeable built-in battery is used for supplying power to the broadband receiving unit, the integrated data processing system and the antenna biasing unit.
2. The marine surface wave radar electromagnetic signal field gauging device according to claim 1, further comprising: the device comprises a bidirectional coupler and an attenuator, wherein when the transmitting power of a ground wave radar transmitter is measured, the bidirectional coupler is installed between the ground wave radar transmitter and a ground wave radar transmitting antenna, the input end of the attenuator is connected with the coupling output end of the bidirectional coupler, and the output end of the attenuator is connected with the input end of the radio frequency and signal processing circuit.
3. The marine ground wave radar electromagnetic signal field metering device of claim 2, wherein the isolation of the two-way coupler is not less than 30 dB.
4. The marine surface wave radar electromagnetic signal field gauging device according to any one of the claims 1-3, wherein said radio frequency and signal processing circuit comprises: the system comprises a radio frequency signal processing subunit, an FPGA-based digital signal processing subunit and a microprocessor, wherein the microprocessor is used for controlling the processing process of the FPGA; and the input signal of the radio frequency and signal processing circuit is output after sequentially passing through the radio frequency signal processing subunit and the digital signal processing subunit.
5. The marine surface wave radar electromagnetic signal field metering device of claim 4, wherein the radio frequency signal processing subunit comprises: local oscillator, radio frequency input attenuator, low pass filter, amplifier, mixer, band pass filter and analog-to-digital converter, input signal pass through in proper order the radio frequency input attenuator low pass filter the amplifier gets into the mixer, the local oscillator signal warp that local oscillator sent the amplifier gets into the mixer, the signal of mixing output passes through behind the band pass filter, obtains the difference frequency signal, the difference frequency signal warp the output behind the analog-to-digital converter.
6. The on-site marine ground wave radar electromagnetic signal metering device of claim 5, wherein the FPGA-based digital signal processing subunit comprises: the digital down-conversion module comprises a multiplier and a direct digital synthesizer, and signals output by the analog-to-digital converter sequentially pass through the digital down-conversion module, the low-pass filtering module, the speed reduction extraction module and the frequency spectrum calculation module and are output.
7. The marine ground wave radar electromagnetic signal field measurement device of claim 1, wherein the standard signal transmitting unit further comprises: the system comprises a processor, a power supply module, a data transmission radio and an antenna; the processor receives external input parameters through a UART interface, forms control parameters of the DDS chip through analysis and processing, and writes the control parameters into the DDS chip through an SPI; the processor is also used for extracting the position information received by the positioning module and transmitting the position information to the comprehensive data processing system through the data transmission radio station and the antenna; and the power supply module supplies power to the standard signal transmitting unit.
8. The on-site marine ground wave radar electromagnetic signal metering device of claim 1, wherein the integrated data processing system comprises a data transmission module, a data processing and analyzing module and a display and control module, the data transmission module is used for completing data transmission, the data processing and analyzing module is used for completing analysis and storage of frequency spectrum characteristic signals, and the display and control module is used for displaying measured data, displaying a human-computer interaction interface and providing input of equipment parameters, equipment measurement parameters and instructions.
9. The on-site marine ground wave radar electromagnetic signal metering device of claim 1, wherein a handle and a road wheel are arranged on the housing.
10. The on-site measuring device for the electromagnetic signals of the ocean ground wave radar as claimed in claim 1, wherein a power supply interface of the comprehensive data processing system, a charging interface of a rechargeable built-in battery, a data transmission interface of the broadband receiving unit, a power display screen of the built-in battery and a starting switch are arranged on the top surface of the shell.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010127087.4A CN111537806A (en) | 2020-02-28 | 2020-02-28 | On-spot metering device of ocean ground wave radar electromagnetic signal |
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| CN202010127087.4A CN111537806A (en) | 2020-02-28 | 2020-02-28 | On-spot metering device of ocean ground wave radar electromagnetic signal |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112730993A (en) * | 2020-12-17 | 2021-04-30 | 北京建筑大学 | Electromagnetic environment monitoring system |
| CN114115436A (en) * | 2021-10-21 | 2022-03-01 | 湖南艾科诺维科技有限公司 | Multi-path parallel DDS bidirectional linear frequency sweeping method, system and medium based on FPGA platform |
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2020
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112730993A (en) * | 2020-12-17 | 2021-04-30 | 北京建筑大学 | Electromagnetic environment monitoring system |
| CN112730993B (en) * | 2020-12-17 | 2023-06-16 | 北京建筑大学 | Electromagnetic environment monitoring system |
| CN114115436A (en) * | 2021-10-21 | 2022-03-01 | 湖南艾科诺维科技有限公司 | Multi-path parallel DDS bidirectional linear frequency sweeping method, system and medium based on FPGA platform |
| CN114115436B (en) * | 2021-10-21 | 2023-06-13 | 湖南艾科诺维科技有限公司 | Multi-path parallel DDS bidirectional linear sweep frequency method, system and medium based on FPGA platform |
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