CN111183741B - Broadband radar target simulation method and system - Google Patents
Broadband radar target simulation method and system Download PDFInfo
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Abstract
The invention relates to a broadband radar target simulation method and a system, which are characterized in that: the received radar radiation signals enter a broadband down converter of an analog system after passing through an attenuator and a low noise amplifier to carry out conversion from radio frequency to intermediate frequency, the down converter outputs intermediate frequency 70MHz band-pass signals, the 70MHz intermediate frequency modulation signals carry out band-pass sampling on the input analog modulation signals after being subjected to low-pass filtering, and the output digital data completes digital down conversion in an FPGA, demodulates digital baseband signals and delays the digital data; and the delayed data is output to an IQ data processing circuit of the FPGA, and finally, the target simulation of the microwave frequency band is completed through the signal output by the DAC to radiate to the radar. The invention adopts space coherent reception, and can completely meet the requirement of radar far field test.
Description
Technical Field
The invention belongs to the technical field of radio frequency simulation, and particularly relates to a broadband radar target simulation method and system for radio frequency radar target simulation, which are mainly used for function test, calibration and debugging of an air defense radar system under an external field environment and a laboratory condition.
Background
The radar target simulator is a product of combining system simulation technology and radar technology, a simulated object is a target and an environment of the radar, and a simulated result is a radio frequency signal containing the target and the environment. The radar target simulator is widely used for testing, calibrating and debugging a radar system. The radar system is functionally tested by utilizing the radar target simulation technology, so that the external field test expenditure can be greatly saved, the radar development and production time is effectively accelerated, and the radar development period is shortened.
Technical reports of 1-18 GHz ultra-wideband radar target simulators are not found in domestic published technical documents, and the main reports of the published technical documents are mainly intermediate-frequency radar target simulators and radar target simulators customized in specific frequency bands, such as:
1. "target distance pulse simulation circuit based on FIFO" (gao shang dong, zhu jia hai) published in "electronic component application". The analog circuit is a digital target analog circuit based on FIFO, and the output signal frequency can only be 30MHz at most due to devices. The range of the target can only be simulated statically, and the amplitude and Doppler frequency of the target cannot be simulated.
2. The 'millimeter wave multi-target signal forming technology research based on FPGA' (Xuman, Su Guangzhou works), published in electronic technology application, adopts DSP and FPGA technology to statically simulate a plurality of targets; the system is applied to the D/A conversion into a video analog signal and then is subjected to quadrature modulation to an intermediate frequency signal, and due to the adoption of a D/A converter technology, the system lacks waveform universality, namely, the system can only aim at a specific radar waveform and does not have the generalization characteristic.
3. The design and implementation of the transmitter of the multi-target simulator of the radiation radar published in the modern radar adopts the DRFM technology to simulate the radar target (Zhao Fei, Zi Hui Ying et al), but the coverage working frequency band is L/S/X, and the transmitter does not have the broadband characteristic.
A1-18 GHz radar target simulation system reported abroad has high instantaneous bandwidth, but is high in manufacturing cost, high in price of millions of dollars, large in size and not suitable for being used in an external environment.
Distance and Doppler simulation are used as important parameters for radar target echo simulation, and the technical difficulty for radar target simulation is that because a simulated target echo signal needs to be synchronous and phase-coherent with a radar transmission signal, and a simulation system is asynchronous with the radar transmission signal, the requirement of the radar on the distance precision of target echo simulation cannot be guaranteed; if the phases are not coherent, the doppler frequency cannot be accurately measured, so that the simulator outputs wrong target speed characteristics, and the doppler calibration of the tested radar cannot be completed.
The existing radar target simulator can be mainly divided into an injection type simulator and a space radiation type simulator, wherein the injection type radar simulator can be divided into a radio frequency injection type simulator, an intermediate frequency injection type simulator and a video injection type simulator, radar radiation signals are not needed when the radar is tested by applying the injection type simulator, echo signals are directly injected into the front end of a receiver, an intermediate frequency processing unit or a video processing unit, the testing method of the mode is simple, but the antenna feeder part of the radar cannot be tested, and meanwhile, the emission and receiving beam direction of the radar cannot be comprehensively tested
The traditional radar target simulation system, no matter the optical fiber delay line method, the surface acoustic wave delay line method and the Digital Radio Frequency Memory (DRFM) delay line method, needs two sets of equipment to respectively complete distance simulation and speed simulation, and the surface acoustic wave delay line method has the defects of large equipment quantity, inflexible delay control, poor precision and the like; although the fiber delay line method has good coherence and high signal transmission quality, it also has disadvantages of large volume, high cost, and inflexible delay control.
In summary, the drawbacks of the prior art are as follows:
①, the existing test equipment cannot complete the search-to-tracking function test;
②, the existing test equipment cannot dynamically simulate the radar target echo characteristics in real time;
the existing test equipment can only test a receiving branch and cannot complete the comprehensive dynamic simulation and test of the whole system of the transmitter → the transmitting antenna → the target → the receiving antenna → the receiver → the signal processing → the data processing → the terminal display control;
the problems of multiple connecting lines, difficult phase-coherent, easy interference on the emission trigger signal and the like exist when the existing test equipment is used for carrying out a target simulation test;
the foreign advanced radar target simulation system has the problems of high price, large volume, poor portability, complex operation and the like, and cannot meet the requirement of domestic radar test.
Disclosure of Invention
In order to avoid the defects of the prior art, the invention provides a broadband radar target simulation method and a broadband radar target simulation system, which are used for solving the technical problems.
A broadband radar target simulation method is characterized by comprising the following steps:
step 1: radar radiation signal V received by antenna of simulatorr＝cos(2πfrt+Φr) Attenuating to make the signal level-10 dBm, and then amplifying with low noise to make the signal level +5 dBm; wherein: f. ofrFor receiving the frequency of the signal, phirInitial phase of the received signal;
step 2: for the signal of step 1, the local oscillator signal V is usedl＝cos(2πfltΦl) Down-converting to convert radio frequency to intermediate frequency to make signalIntermediate frequency signal V with 70MHz levelI＝cos[2π(fr-fl)t+(Φr-Φl)](ii) a Wherein: f. oflIs the local oscillator signal frequency, philIs the initial phase of the local oscillation signal;
and step 3: performing low-pass filtering on the 70MHz intermediate frequency modulation signal and then performing analog-to-digital conversion to obtain a digital signal; the high-frequency cut-off frequency of the low-pass filtering is 80 MHZ;
and 4, step 4: carrying out down-conversion DDC on the digital signal to obtain a demodulated baseband IQ data signal;
and 5: low-pass filtering the IQ data signal; the high-frequency cutoff frequency of the low-pass filtering is 20 MHZ;
step 6: time-delaying the low-pass filtered signal; the time delay time is 3-600 microseconds;
and 7: then, performing digital-to-analog conversion to obtain an analog signal;
and 8: the analog signal is up-converted into a microwave modulation signal V of the broadband radar target by the same local oscillatort＝cos[2π(fr-fl+fl)t+(Φr-Φl+Φl)]＝cos(2πfrt+Φr)。
A system for realizing the broadband radar target simulation method is characterized by comprising a broadband microwave front end, a local oscillator unit and a range Doppler simulation unit, wherein the broadband microwave front end consists of a receiving unit and a transmitting unit; the receiving unit comprises a broadband receiving antenna, a broadband low-noise amplifier, a broadband down converter, a low-pass filter, an intermediate frequency amplifier, a power divider and a radio frequency pulse extraction circuit which are connected in parallel, wherein the broadband low-noise amplifier, the broadband down converter, the low-pass filter and the intermediate frequency amplifier are connected in sequence; the transmitting unit comprises an intermediate frequency amplifier, a numerical control attenuator, a low-pass filter, a broadband up-converter and a band transmitting antenna which are connected in sequence; the distance Doppler analog unit comprises a low-pass filter, an analog-to-digital converter (ADC), a memory, a direct digital frequency synthesizer (DDS) and a trigger synchronous circuit which are connected in sequence, and the field programmable logic device (FPGA) is connected with the control ADC, the memory, the DDS and the trigger synchronous circuit; the local oscillator unit is connected with the broadband down converter and the broadband up converter; the output end of the power divider is connected with the input end of the distance Doppler simulation unit; the output end of the radio frequency pulse extraction circuit is connected with the trigger end of the range Doppler analog unit.
The method and the system for simulating the broadband radar target adopt space coherent reception, realize the modulation of information such as distance, Doppler and the like, and radiate an echo signal to a radar receiver through an antenna. The simulation technology can realize full-function test of the radar system, can simultaneously complete comprehensive test of the radar transmitting branch and the radar receiving branch, and can completely meet the requirement of radar far-field test due to the fact that the space distance is usually required to be opened.
The invention adopts the digital radio frequency storage (DRFM) technology to select the technical scheme to complete the realization of the range delay and the Doppler frequency modulation of the radar. The method adopts the mode of separately arranging the transmitting and receiving antennas in the aspect of processing the transmitting and receiving isolation degree, so that the transmitting signal of the simulator can not enter a receiving channel to form secondary echo, and the quality of signal output of the simulator is influenced.
The invention adopts an ultra wide band design idea to adapt to the test requirements of radars of different systems, and the system working bandwidth is designed to be in a frequency range of 1-18 GHz, so that the radar covers radars of L wave band, S wave band, C wave band, X wave band and Ku wave band, and is mainly used for space radiation type radio frequency semi-physical simulation test under the condition of an external field. In addition, the simulator can meet the semi-physical simulation test of 8mm and 3mm frequency band radar seeker systems by matching with the millimeter wave front end. The radar target simulation system can complete the test of a radar system in a frequency range of 1-18 GHz, the instantaneous bandwidth of the system is 20MHz, the test requirements of most radar systems can be met, the system can complete laboratory-level and external field-level simulation tests, the function test of space radiation type simulation and injection type simulation can be simultaneously realized, and the system has the characteristics of integration, portability and low cost.
By adopting the technical scheme, compared with the prior art, the invention has the following technical characteristics:
1. the broadband radar target simulation system adopts an advanced Digital Radio Frequency Memory (DRFM) technology, so that the simulation system has good universality and flexibility, and a simulation test can be carried out without predicting a radar emission waveform in advance;
2. the technical problem of radar target simulation of high duty ratio (more than 90% duty ratio), large pulse width (pulse width is more than 10ms) quasi-continuous wave and frequency modulation continuous wave system is solved;
3. the distance delay simulation method has the technical characteristics of realizing the distance delay simulation of the large pulse width signal by using a small storage space;
4. the broadband radar target simulation system adopts a set of equipment to simultaneously complete the simulation of distance and Doppler frequency modulation;
5. when a search transition tracking test is carried out, the system adopts a forwarding type simulation technology, namely what waveform is transmitted by a radar, the simulation system forwards the radar waveform signal, the working modes and the waveform synchronism of the simulation system and the radar system are ensured, the correctness of the radar working mode switching function verification is ensured, and the radar system is not required to output the working state, the working time sequence and the working waveform parameters (pulse width, signal bandwidth, waveform type, repetition period and the like) of the system in real time;
6. the problem that the existing test equipment can only test a receiving branch and cannot complete the full-system comprehensive dynamic simulation and test of the transmitter → the transmitting antenna → the target → the receiving antenna → the receiver → the signal processing → the data processing → the terminal display control is solved;
7. the problems that the existing test equipment has many connecting lines, is difficult to be coherent, and easily interferes the emission trigger signal when a target simulation test is carried out are solved, and when a radiation type semi-physical simulation test is carried out, the radar is not required to provide control signals such as a 10MHz reference signal, the emission trigger signal, a radar working mode, a working state and the like, and only the radar is normally started to carry out an echo simulation test on the emission signal of the air radiation radar;
8. the simulation system has the remarkable characteristics of wide frequency coverage range, strong universality, high flexibility, small size, portability, low cost and the like, can realize the function of remote control, and can avoid microwave radiation damage to a user without directly transmitting signals to a radar and can carry out semi-physical simulation test without compiling radar waveforms by the user, thereby greatly simplifying the complexity and the operation flow of the simulation test and being very suitable for being used as radar external field test calibration test equipment.
Drawings
FIG. 1: the invention relates to a broadband radar target simulation system which generally comprises a block diagram;
FIG. 2: the invention relates to a broadband radar target simulation system broadband microwave front end composition block diagram;
FIG. 3: the invention relates to a signal processing schematic block diagram of a range-Doppler simulation unit of a broadband radar target simulation system;
FIG. 4: the invention discloses a schematic block diagram of a verification test of a broadband radar target simulation system.
Detailed Description
The invention will now be further described with reference to the following examples and drawings:
the invention relates to a broadband radar target simulation system, which mainly comprises a broadband microwave front end, a local oscillator unit, a range-Doppler simulation unit, a power supply, a case, a control computer, embedded real-time software, an LCD display screen, a broadband antenna, a point-to-point wireless network bridge and the like, wherein the broadband microwave front end and the local oscillator unit carry out down-conversion on radar transmitting signals from space to 70MHz intermediate frequency signals through a receiving antenna, the 70MHz intermediate frequency signals are subjected to range and Doppler modulation and forwarding in the range-Doppler simulation unit, then the same local oscillator signals of the local oscillator unit are subjected to up-conversion to received microwave frequency, finally the signals are radiated to a radar receiving antenna through the transmitting antenna of the broadband radar target simulation system, and a radar measures echoes and reports target distance, speed, direction and pitching parameters. In consideration of the safety problem of electromagnetic radiation, the broadband radar target simulation system ensures that a user is not irradiated by microwaves for a long time, and is specially provided with a pair of point-to-point wireless bridges for realizing a remote control function, so that an operator does not need to directly face the radiation of a radar transmitting signal, and even can carry out remote control on a console of a radar shelter, thereby facilitating the comparison of simulated target parameters and target parameters actually reported by the radar.
The broadband microwave front end of the broadband radar target simulation system is designed by considering the wide frequency coverage range (1-18 GHz) of the simulation system, and if frequency preselection is adopted on radar signals, the microwave front end part has high cost and complex equipment, and meanwhile, the whole simulator has huge volume and loses the original design purpose of low cost and portability. Based on the above analysis, a one-time frequency conversion scheme is adopted for design. This unit performs the following functions:
●, coherent reception, amplification/filtering and down-conversion of 1-18 GHz radar transmission signals are completed, and 70MHz intermediate frequency band signals are output to an IF in end of a range-Doppler analog unit
● extracting pulse signals emitted by radar, converting into TTL level, and providing to trigger end of range-Doppler analog unit
● amplifying/filtering IF out 70MHz intermediate frequency signal of range-Doppler analog unit and up-converting to 1-18 GHz
Referring to fig. 2, the broadband microwave front end and the local oscillation unit work cooperatively to complete frequency conversion from microwave to intermediate frequency and from intermediate frequency to microwave. The system work flow is as follows: the radar signal enters a receiving channel of a broadband microwave front end after passing through a receiving antenna, and considering that a radar transmitting signal is generally strong, a broadband variable attenuator is firstly accessed to the foremost end of the receiving channel during design so as to ensure that the transmitting signal cannot burn out the front end of the receiving channel of a simulator, and the output signal of the broadband attenuator is subjected to broadband low-noise amplification and enters a down converter unit; the down converter unit mainly converts the microwave signal to an intermediate frequency signal, and is used for the distance Doppler analog unit to perform intermediate frequency processing, copying and forwarding. The specific principle is as follows: microwave signals from a receiving channel and a local oscillator unit of the simulator are subjected to down-conversion through a mixer, output signals enter a low-pass filter to filter out unwanted high-frequency signals, and intermediate-frequency signals output by the filter are divided into two paths: one path directly enters the range-Doppler analog unit, and the other path is provided for the radio frequency pulse detection unit to complete the extraction of pulse signals; the radio frequency pulse detection unit mainly extracts the pulse envelope of the radar emission signal, converts the analog signal into a TTL digital signal through an analog-to-digital conversion circuit and provides a zero-range pulse reference signal for the range-Doppler analog unit, namely, the radio frequency delay of the analog system takes the signal as a reference. If the signal is not available, the signal output by the simulator does not contain distance delay information, and the function test of radar distance simulation cannot be completed. The unit mainly comprises a detection diode, a logarithmic amplification circuit, a comparator and the like, wherein an output signal is a positive pulse signal of TTL (transistor-transistor logic) and is used for driving the triggering synchronization of the range-Doppler unit, namely once the rising edge of a pulse arrives, the range-Doppler simulation unit starts the read-write operation of FIFO (first in first out), the acquisition, storage, range-Doppler information modulation and forwarding of radar emission signals are completed, an intermediate frequency signal output by the range-Doppler simulation unit is moved to the microwave frequency through an up-conversion unit and is output to an antenna through an isolator to radiate towards the radar direction, and the space far-field radiation type simulation is completed. The working principle is as follows: intermediate frequency signals output by the range Doppler unit are subjected to intermediate frequency amplification and numerical control attenuation firstly, output signals enter an IF end of a microwave mixer, local oscillation signals output by a local oscillation unit enter an LO end of the microwave mixer through a broadband power distributor, up-conversion signals are output by an RF end of the microwave mixer and are radiated to space through a transmitting antenna, and a radar detects and tracks simulated target echoes and forms a target track.
Referring to fig. 3, the range-doppler analog unit is a core component of a wideband radar target analog system, and mainly includes an analog-to-digital converter (ADC), an analog-to-digital converter (DAC), a field programmable logic device (FPGA), a trigger synchronization circuit, and embedded control software, where a 70MHz intermediate frequency modulation signal is low-pass filtered and enters the ADC, the ADC samples the input analog modulation signal in real time under the action of a sampling clock, and completes Digital Down Conversion (DDC) in the FPGA, once a rising edge of the trigger signal arrives, data is immediately written into the FIFO for high-speed cache, when a delay time arrives, an FIFO read signal is valid, an FIFO read operation is started, the data is read out to a signal processing circuit of the FPGA, the data interpolation, digital quadrature up conversion, and DDS design are completed, finally, the analog signal output is completed through a built-in 14-bit analog-to-digital converter of the DAC, and the signal output from the DAC is low-pass filtered and then output to an intermediate frequency input end .
The unit fully utilizes a software radio design idea to complete the realization of a Digital Radio Frequency Memory (DRFM) technology, performs intermediate frequency sampling, digital orthogonal down-conversion, data storage and processing and digital orthogonal up-conversion on radar transmitting signals, adds distance delay, Doppler velocity modulation information and the like to the radar transmitting signals, realizes coherent replication, forwarding, distance and velocity modulation on the radar transmitting signals, and controls the frequency of a tunable local oscillator and the power of radio frequency output signals. Because the range-doppler analog unit adopts a Digital Radio Frequency Memory (DRFM) technology, i.e., coherent storage of radar transmission signals, complex radar signals such as simple pulse modulation signals, linear frequency modulation signals, nonlinear frequency modulation signals, phase coding signals and the like can be adaptively processed in signal form.
The analysis of the coherence of the simulated system is as follows:
simulator received signal Vr＝cos(2πfrt+Φr) (1)
frFrequency of received signals, phir-receiving a signal initial phase;
local oscillator signal V of analog systeml＝cos(2πfltΦl) (2)
flLocal oscillator signal frequency, phil-local oscillator signal initial phase;
down-conversion output intermediate frequency signal VI＝cos[2π(fr-fl)t+(Φr-Φl)](3)
The same local oscillator of the local oscillator unit up-converts the output transmitting signal again
Vt＝cos[2π(fr-fl+fl)t+(Φr-Φl+Φl)]＝cos(2πfrt+Φr) (4)
It is easy to deduce that the analog system and the radar system are strictly phase-coherent, mainly because the analog system shares the same local oscillator for transceiving, and the ADC and DAC of the range-doppler analog unit share the same clock reference, even if there is a phase difference, the phase difference is constant with time, so the present invention meets the technical requirements of phase coherence.
Referring to fig. 4, the wideband radar target simulation system performs function verification on a radar, the simulation system is erected at a height of about 8 meters from the ground, the radar is 40 meters away from the simulation system, and the radar is erected on the ground. Description of the test principle: the radar azimuth 360-degree mechanical scanning pitching electric scanning device comprises a radar azimuth 360-degree mechanical scanning pitching electric scanning device, wherein when a radar emission signal sweeps the azimuth and the pitching of a target simulator, the simulator receives the radar signal in real time, completes storage and copying of the radar emission signal, adds the distance and speed modulation information of the target in real time to form real-time simulation of a dynamic target, finally radiates a target echo to the air through a transmitting antenna, and when a radar emission beam leaves the position of the simulator, the simulator does not output the target echo. After receiving a target echo signal radiated by the simulator, the radar detects and searches the target echo signal, forms a target navigation curve after continuously measuring the target, and reports the measurement parameters of the target on a data terminal. The test result shows that the distance in the target distance parameters reported on the radar PPI interface is from 3 kilometers to about 13 kilometers, and the target distance parameters are basically consistent with the flight path set by the simulation system, so that the simulation system works normally, can complete the real-time simulation of the dynamic target, and is used for debugging of a radar master station and semi-physical simulation testing.
The control flow of the target simulation system of the invention is as follows: the simulator receives radar radiation signals from space through an antenna, the radar radiation signals enter a broadband down converter of a simulation system after passing through an attenuator and a low noise amplifier to carry out conversion from radio frequency to intermediate frequency, the down converter outputs intermediate frequency 70MHz band-pass signals, 70MHz intermediate frequency modulation signals enter an ADC after low-pass filtering, the ADC carries out band-pass sampling on input analog modulation signals under the action of a sampling clock, output digital data complete signal processing work such as Digital Down Conversion (DDC) and digital low-pass filtering in an FPGA, digital baseband signals are demodulated, once triggering occurs, the data are written into a high-speed FIFO memory constructed by the FPGA according to a clock cycle sequence to be cached, and FIFO reading signals are waited to be effective,and outputting the delayed data to an IQ data processing circuit of the FPGA to complete data interleaving, digital filtering, digital orthogonal up-conversion and presetting of frequency control words, finally completing the output of analog signals through a DAC, outputting the signals output by the DAC to a medium-frequency input end at the front end of a broadband microwave for frequency conversion after low-pass filtering, finally completing the target simulation of a microwave frequency band, and transmitting the signals to a radar through a simulator to radiate to the radar. The control software part is designed as follows: first a FIFO is designed for caching of data and then FIFO write enable signal WR and read enable signal RD are generated, 2 counters: ADC counter and dacccounter, 1 controlled variable: distance delay-delay, 1 signal: launch trigger-trigger. The ADC collects signals in real time, when the rising edge of the Trigger signal arrives, the WR high level of the write enable signal is effective, the FIFO starts to be allowed to be written, meanwhile, the Trigger carries out zero clearing operation on the ADC counter, 1 count is added until the rising edge of the Trigger signal arrives again, and the ADC counter is set to be 0; when the ADC counter is in an effective condition, the ADC data is subjected to FIFO writing operation according to the sampling clock period, once the FIFO full mark is effective, the WR is changed from a high level to a low level, and the FIFO writing operation is forbidden to be continued; once the ADC counter is greater than the delay value, the high level of the read enable signal RD is effective, the DAC counter is cleared and starts to add 1 for counting, FIFO reading operation is started until all data in the FIFO are read, at the moment, the RD is set to be 0, the data in the FIFO are forbidden to be output to the DAC, and the FPGA outputs the Doppler frequency f calculated by the upper computerdAnd an intermediate frequency carrier frequency f0And converting the signal into a corresponding frequency control word, outputting the frequency control word to a DDS core of the FPGA, outputting an intermediate frequency continuous wave signal with Doppler frequency modulation, performing digital quadrature up-conversion on the signal and a delayed digital baseband IQ modulation signal in the DAC, and outputting the signal to finish the distance delay and Doppler frequency modulation of the radar echo signal. The output intermediate frequency signal is output by a broadband up-converter after filtering, amplifying and numerical control attenuating, the simulation of the amplitude modulation characteristic of the target echo is realized, finally, the generated microwave modulation signal is radiated to a radar through a transmitting antenna, and the space radiation simulation of the radio frequency signal is completed. In addition, the system can also complete an injection type simulation test: feeding the frequency synthesis excitation signal of the radar into the simulationAnd the receiving end of the simulator and the transmitting end of the simulator are directly injected into the input end of the radar receiver.
Meanwhile, the invention also has the technical characteristic of utilizing a smaller FIFO storage space to finish the distance delay simulation of a large pulse width signal, and the delay distance is determined by the depth of a memory, which is different from the traditional Digital Radio Frequency Memory (DRFM) technology, and the invention adopts another special technology when the large time width exceeds the FIFO storage depth, and the method is as follows: by utilizing the characteristic of FIFO memory FIFO, the pipeline design method is adopted, after the FIFO writing operation is started, the FIFO reading operation is started immediately after the delay condition is met, the data in the FIFO is read out in time, thereby ensuring that the data in the FIFO can never be full, ensuring that the signal can be continuously written and continuously delayed, and ensuring that the continuous delay output can be realized even if the pulse width is far greater than the storage depth of the FIFO.
Claims (4)
1. A broadband radar target simulation method is characterized by comprising the following steps:
step 1: radar radiation signal V received by antenna of simulatorr＝cos(2πfrt+Φr) Attenuating to make the signal level-10 dBm, and then amplifying with low noise to make the signal level +5 dBm; wherein: f. ofrFor receiving the frequency of the signal, phirInitial phase of the received signal;
step 2: the local oscillation signal V is used for the signal amplified by the low noise in the step 11＝cos(2πf1t+Φ1) Down-converting the radio frequency to an intermediate frequency to a signal level of a 70MHz intermediate frequency modulated signal VI＝cos[2π(fr-f1)t+(Φr-Φ1)](ii) a Wherein: f. of1Is the local oscillator signal frequency, phi1Is the initial phase of the local oscillation signal;
and step 3: performing low-pass filtering on the 70MHz intermediate frequency modulation signal and then performing analog-to-digital conversion to obtain a digital signal; the high-frequency cut-off frequency of the low-pass filtering is 80 MHz;
and 4, step 4: carrying out down-conversion DDC on the digital signal to obtain a demodulated baseband IQ data signal;
and 5: low-pass filtering the IQ data signal; the high-frequency cut-off frequency of the low-pass filtering is 20 MHz;
step 6: time-delaying the low-pass filtered signal; the time delay time is 3-600 microseconds;
and 7: then, performing digital-to-analog conversion to obtain an analog signal;
and 8: the analog signal is up-converted into a microwave modulation signal V of the broadband radar target by the same local oscillatort＝cos[2π(fr-f1+f1)t+(Φr-Φ1+Φ1)]＝cos(2πfrt+Φr)。
2. A system for implementing the wideband radar target simulation method of claim 1, comprising a wideband microwave front end composed of a receiving unit and a transmitting unit, a local oscillator unit and a range-doppler simulation unit; the receiving unit comprises a broadband receiving antenna, a broadband low-noise amplifier, a broadband down converter, a first low-pass filter, a first intermediate frequency amplifier, a power divider and a radio frequency pulse extraction circuit which are connected in parallel, wherein the broadband low-noise amplifier, the broadband down converter, the first low-pass filter and the first intermediate frequency amplifier are connected in sequence; the transmitting unit comprises a second intermediate frequency amplifier, a numerical control attenuator, a second low-pass filter, a broadband up-converter and a band transmitting antenna which are sequentially connected; the distance Doppler analog unit comprises a third low-pass filter, an analog-to-digital converter (ADC), a memory, a direct digital frequency synthesizer (DDS) and a trigger synchronous circuit which are connected in sequence, and the field programmable logic device (FPGA) is connected with the control ADC, the memory, the DDS and the trigger synchronous circuit; the local oscillator unit is connected with the broadband down converter and the broadband up converter; the output end of the power divider is connected with the input end of the distance Doppler simulation unit; the output end of the radio frequency pulse extraction circuit is connected with the trigger end of the range Doppler analog unit.
3. The system of claim 2, wherein the control process of the broadband microwave front-end is: microwave signals and local oscillator units from a receiving channel are down-converted through a broadband down converter, output signals enter a low-pass filter to filter out unnecessary high-frequency signals, and intermediate-frequency signals output by the low-pass filter are divided into two paths: one path directly enters the range-Doppler analog unit, and the other path is provided for the radio-frequency pulse detection unit to finish the extraction of pulse signals and provide a zero-range pulse reference signal for the range-Doppler analog unit; and meanwhile, an output signal of the range-Doppler simulation unit is received, an intermediate-frequency signal output by the range-Doppler simulation unit is shifted to a microwave frequency through a broadband up-converter, and the intermediate-frequency signal is output to an antenna through an isolator and radiated in the direction of a radar to complete space far-field radiation type simulation.
4. The system according to claim 2, wherein the control procedure of the range-doppler modeling unit is: the method comprises the steps that a 70MHz intermediate frequency modulation signal enters an ADC after low-pass filtering, the ADC samples an input analog modulation signal in real time under the action of a sampling clock, digital down-conversion DDC is completed in an FPGA, once a rising edge of a trigger signal arrives, data are written into an FIFO for high-speed caching, when delay time arrives, FIFO reading signals are effective, FIFO reading operation is started, the data are read to a signal processing circuit of the FPGA, interpolation, digital quadrature up-conversion and DDS of the data are completed, finally, output of the analog signal is completed through a built-in 14bit digital-to-analog converter of the DAC, and the signal output by the DAC is output to an intermediate frequency input end of a broadband micro front end after low-pass filtering to perform frequency conversion.
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Cited By (28)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107907877A (en) * | 2017-10-31 | 2018-04-13 | 天津大学 | A kind of indoor distances alignment system based on Doppler effect |
| CN108919246A (en) * | 2018-07-12 | 2018-11-30 | 中国船舶重工集团公司第七二四研究所 | A kind of design method of ultra wide band single-conversion multi-channel digital receiving unit |
| CN109459733A (en) * | 2018-10-26 | 2019-03-12 | 中电科仪器仪表有限公司 | Anticollision Radar target velocity simulator, system and method based on pm mode |
| CN109471076A (en) * | 2018-10-19 | 2019-03-15 | 芜湖易来达雷达科技有限公司 | A kind of millimetre-wave radar non-contact test method |
| CN109557516A (en) * | 2018-11-28 | 2019-04-02 | 四川九洲电器集团有限责任公司 | The rapid generation of multiple target spacing wave |
| CN109683139A (en) * | 2018-12-24 | 2019-04-26 | 中国电子科技集团公司第二十研究所 | A kind of radio frequency based on double sampled rate directly adopts digital transceiver circuits |
| CN109884603A (en) * | 2019-03-14 | 2019-06-14 | 中国人民解放军海军航空大学青岛校区 | Radar target simulation system and method based on PXI cabinet |
| CN109917342A (en) * | 2019-03-11 | 2019-06-21 | 南京理工大学 | A kind of Radar Simulation Platform of intermediate-freuqncy signal and digital signal double mode |
| CN110287134A (en) * | 2019-07-02 | 2019-09-27 | 南京国睿安泰信科技股份有限公司 | A kind of continuous-flow type digital radiofrequency memory module |
| CN111007469A (en) * | 2019-12-25 | 2020-04-14 | 上海铭剑电子科技有限公司 | Receiver of radar simulator |
| CN111289952A (en) * | 2020-03-27 | 2020-06-16 | 华清瑞达（天津）科技有限公司 | Radar target echo simulation method and device |
| CN111474525A (en) * | 2020-04-16 | 2020-07-31 | 上海交通大学 | Ultra-wideband radar target echo signal simulation method and simulator |
| CN111505594A (en) * | 2020-04-30 | 2020-08-07 | 中国直升机设计研究所 | Portable radar signal simulator |
| CN111505589A (en) * | 2020-04-21 | 2020-08-07 | 湖南赛博诺格电子科技有限公司 | Inter-pulse coherent false target interference method and device and computer equipment |
| CN111562568A (en) * | 2020-04-30 | 2020-08-21 | 北京卫星信息工程研究所 | Radar transmitting end, receiving end, frequency synchronization method and transceiving networking radar |
| CN111664740A (en) * | 2020-05-28 | 2020-09-15 | 中国人民解放军32181部队 | Passive microwave communication adapter and system |
| CN111812592A (en) * | 2020-06-16 | 2020-10-23 | 南京云航信息技术有限公司 | Arbitrary waveform broadband radar intermediate frequency signal source |
| CN111812604A (en) * | 2020-07-21 | 2020-10-23 | 中国人民解放军海军航空大学 | Full-coherent millimeter wave target simulator with composite seeker |
| CN111856419A (en) * | 2020-07-30 | 2020-10-30 | 重庆市计量质量检测研究院 | Indoor positioning simulation method based on ultra-wideband radar |
| CN112485768A (en) * | 2020-11-16 | 2021-03-12 | 西安电子工程研究所 | High-precision continuous wave speed measuring radar echo simulation method based on frequency division and multiplication mode |
| CN112782654A (en) * | 2019-11-08 | 2021-05-11 | 北京振兴计量测试研究所 | Phased array radar target echo signal simulation system |
| CN113219420A (en) * | 2020-01-21 | 2021-08-06 | 安波福技术有限公司 | High-fidelity radar simulator |
| CN113608183A (en) * | 2021-08-03 | 2021-11-05 | 中国人民解放军海军大连舰艇学院 | Hypersonic broadband radio frequency target simulation system |
| CN113777565A (en) * | 2021-09-02 | 2021-12-10 | 上海矽杰微电子有限公司 | Miniaturized millimeter wave radar simulation method |
| CN114859308A (en) * | 2022-07-11 | 2022-08-05 | 陕西昱琛航空设备股份有限公司 | Radar target simulator and calibration method thereof |
| CN115001926A (en) * | 2022-07-05 | 2022-09-02 | 创远信科(上海)技术股份有限公司 | System for realizing multichannel coherent transmitting function based on broadband modulator |
| CN115333567A (en) * | 2022-10-14 | 2022-11-11 | 南京冉思电子科技有限公司 | Unmanned aerial vehicle target simulation ware frequency conversion and fiber module |
| CN116136584A (en) * | 2023-04-14 | 2023-05-19 | 北京中科睿信科技有限公司 | FPGA and DDR 4-based large-bandwidth beyond-view-range radar distance simulation device and method |
-
2012
- 2012-09-06 CN CN201218003961.XA patent/CN111183741B/en not_active Expired - Fee Related
Cited By (38)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107907877A (en) * | 2017-10-31 | 2018-04-13 | 天津大学 | A kind of indoor distances alignment system based on Doppler effect |
| CN108919246A (en) * | 2018-07-12 | 2018-11-30 | 中国船舶重工集团公司第七二四研究所 | A kind of design method of ultra wide band single-conversion multi-channel digital receiving unit |
| CN109471076A (en) * | 2018-10-19 | 2019-03-15 | 芜湖易来达雷达科技有限公司 | A kind of millimetre-wave radar non-contact test method |
| CN109459733A (en) * | 2018-10-26 | 2019-03-12 | 中电科仪器仪表有限公司 | Anticollision Radar target velocity simulator, system and method based on pm mode |
| CN109557516A (en) * | 2018-11-28 | 2019-04-02 | 四川九洲电器集团有限责任公司 | The rapid generation of multiple target spacing wave |
| CN109683139A (en) * | 2018-12-24 | 2019-04-26 | 中国电子科技集团公司第二十研究所 | A kind of radio frequency based on double sampled rate directly adopts digital transceiver circuits |
| CN109683139B (en) * | 2018-12-24 | 2022-08-23 | 中国电子科技集团公司第二十研究所 | Radio frequency direct sampling digital transceiver circuit based on double sampling rates |
| CN109917342A (en) * | 2019-03-11 | 2019-06-21 | 南京理工大学 | A kind of Radar Simulation Platform of intermediate-freuqncy signal and digital signal double mode |
| CN109884603A (en) * | 2019-03-14 | 2019-06-14 | 中国人民解放军海军航空大学青岛校区 | Radar target simulation system and method based on PXI cabinet |
| CN110287134A (en) * | 2019-07-02 | 2019-09-27 | 南京国睿安泰信科技股份有限公司 | A kind of continuous-flow type digital radiofrequency memory module |
| CN112782654A (en) * | 2019-11-08 | 2021-05-11 | 北京振兴计量测试研究所 | Phased array radar target echo signal simulation system |
| CN112782654B (en) * | 2019-11-08 | 2023-11-03 | 北京振兴计量测试研究所 | Phased array radar target echo signal simulation system |
| CN111007469A (en) * | 2019-12-25 | 2020-04-14 | 上海铭剑电子科技有限公司 | Receiver of radar simulator |
| CN113219420A (en) * | 2020-01-21 | 2021-08-06 | 安波福技术有限公司 | High-fidelity radar simulator |
| CN111289952A (en) * | 2020-03-27 | 2020-06-16 | 华清瑞达（天津）科技有限公司 | Radar target echo simulation method and device |
| CN111289952B (en) * | 2020-03-27 | 2023-08-15 | 华清瑞达（天津）科技有限公司 | Radar target echo simulation method and device |
| CN111474525A (en) * | 2020-04-16 | 2020-07-31 | 上海交通大学 | Ultra-wideband radar target echo signal simulation method and simulator |
| CN111505589A (en) * | 2020-04-21 | 2020-08-07 | 湖南赛博诺格电子科技有限公司 | Inter-pulse coherent false target interference method and device and computer equipment |
| CN111505589B (en) * | 2020-04-21 | 2022-03-11 | 湖南赛博诺格电子科技有限公司 | Inter-pulse coherent false target interference method and device and computer equipment |
| CN111562568B (en) * | 2020-04-30 | 2022-05-24 | 北京卫星信息工程研究所 | Radar transmitting end, receiving end, frequency synchronization method and transceiving networking radar |
| CN111562568A (en) * | 2020-04-30 | 2020-08-21 | 北京卫星信息工程研究所 | Radar transmitting end, receiving end, frequency synchronization method and transceiving networking radar |
| CN111505594A (en) * | 2020-04-30 | 2020-08-07 | 中国直升机设计研究所 | Portable radar signal simulator |
| CN111664740A (en) * | 2020-05-28 | 2020-09-15 | 中国人民解放军32181部队 | Passive microwave communication adapter and system |
| CN111812592A (en) * | 2020-06-16 | 2020-10-23 | 南京云航信息技术有限公司 | Arbitrary waveform broadband radar intermediate frequency signal source |
| CN111812592B (en) * | 2020-06-16 | 2024-01-19 | 南京安麦森电子科技有限公司 | Arbitrary waveform broadband radar intermediate frequency signal source |
| CN111812604B (en) * | 2020-07-21 | 2023-04-18 | 中国人民解放军海军航空大学 | Full-coherent millimeter wave target simulator with composite seeker |
| CN111812604A (en) * | 2020-07-21 | 2020-10-23 | 中国人民解放军海军航空大学 | Full-coherent millimeter wave target simulator with composite seeker |
| CN111856419A (en) * | 2020-07-30 | 2020-10-30 | 重庆市计量质量检测研究院 | Indoor positioning simulation method based on ultra-wideband radar |
| CN112485768B (en) * | 2020-11-16 | 2023-07-21 | 西安电子工程研究所 | High-precision continuous wave speed measuring radar echo simulation method based on frequency division and multiplication mode |
| CN112485768A (en) * | 2020-11-16 | 2021-03-12 | 西安电子工程研究所 | High-precision continuous wave speed measuring radar echo simulation method based on frequency division and multiplication mode |
| CN113608183A (en) * | 2021-08-03 | 2021-11-05 | 中国人民解放军海军大连舰艇学院 | Hypersonic broadband radio frequency target simulation system |
| CN113608183B (en) * | 2021-08-03 | 2024-04-26 | 中国人民解放军海军大连舰艇学院 | Hypersonic broadband radio frequency target simulation system |
| CN113777565A (en) * | 2021-09-02 | 2021-12-10 | 上海矽杰微电子有限公司 | Miniaturized millimeter wave radar simulation method |
| CN115001926A (en) * | 2022-07-05 | 2022-09-02 | 创远信科(上海)技术股份有限公司 | System for realizing multichannel coherent transmitting function based on broadband modulator |
| CN114859308A (en) * | 2022-07-11 | 2022-08-05 | 陕西昱琛航空设备股份有限公司 | Radar target simulator and calibration method thereof |
| CN115333567A (en) * | 2022-10-14 | 2022-11-11 | 南京冉思电子科技有限公司 | Unmanned aerial vehicle target simulation ware frequency conversion and fiber module |
| CN115333567B (en) * | 2022-10-14 | 2023-02-28 | 南京冉思电子科技有限公司 | Unmanned aerial vehicle target simulation ware frequency conversion and fiber module |
| CN116136584A (en) * | 2023-04-14 | 2023-05-19 | 北京中科睿信科技有限公司 | FPGA and DDR 4-based large-bandwidth beyond-view-range radar distance simulation device and method |
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