CN113608183A - Hypersonic broadband radio frequency target simulation system - Google Patents

Abstract

The invention discloses a hypersonic broadband radio frequency target simulation system, which comprises: the device comprises a radar signal receiving frequency conversion module, a target time delay digital frequency storage module, a Doppler signal generation module, an instantaneous frequency measurement module, a signal amplitude and broadband power amplification module, a broadband local oscillator module and a control module. By adopting the technical scheme of the invention, the hypersonic radio frequency simulation target can be generated by accurately controlling the distance change, Doppler frequency shift and amplitude change characteristics of the radio frequency simulation target, so that the hypersonic radio frequency simulation target is consistent with a real hypersonic moving target.

Description

A Hypersonic Broadband Radio Frequency Target Simulation System

technical field

The invention belongs to the technical field of radar target simulation, and in particular relates to a hypersonic broadband radio frequency target simulation system, in particular to a shipborne radar hypersonic broadband radio frequency target simulation generation device, which can solve the problem that the shipborne radar lacks hypersonic speed in training. target matching problem.

Background technique

At present, with the development of hypersonic weapons, military powers such as the United States and Russia have successively announced development plans for hypersonic missiles and hypersonic UAVs, and the target flight speed can reach Mach 6 or more. The high-speed movement of the target will cause the change rate of the radial distance of the target to change to a higher power, which makes it difficult for the radar to record and track the target, and the defense is extremely difficult. At present, many radar target simulation devices have been developed. The functions of these devices are mainly to simulate the generation of conventional target signals, mainly for the simulation of conventional ordinary moving speed targets, and there is no method and equipment for generating hypersonic target signals.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a hypersonic broadband radio frequency target simulation system, which can provide the radar with a radio frequency simulation target with a maximum speed of Mach 13, which is used for the detection performance inspection and efficiency evaluation of the hypersonic target by the radar.

For achieving the above object, the present invention adopts the following technical scheme:

A hypersonic broadband radio frequency target simulation system, comprising: a radar signal receiving frequency conversion module, a target delay digital frequency storage module, a Doppler signal generation module, an instantaneous frequency measurement module, a signal amplitude and broadband power amplifier module, and a broadband local oscillator module , control module; among them,

The received radar signal is filtered and linearly amplified with low noise by the radar signal receiving and frequency conversion module, and then mixed with the local oscillator signal generated by the broadband local oscillator module to obtain an intermediate frequency signal, which is output to the target delay digital frequency storage module. The time delay value is read in the control module to simulate the distance change of the hypersonic moving target; then the Doppler frequency shift modulation information is added through the Doppler signal generation module, and the Doppler frequency shift value is also read from the control module Finally, the control module calculates the attenuation value at the current distance of the target in real time, and realizes the accurate simulation of the target signal amplitude through the signal amplitude and broadband power amplifier module; the instantaneous frequency measurement module accurately measures the radar signal in real time The control module provides the target delay digital frequency storage module and the Doppler signal generation module with the precise radar radiation signal frequency under test, and realizes the correlation between the simulated hypersonic radio frequency target signal and the radar signal under test.

Preferably, the radar signal receiving frequency conversion module is used to receive the radar radiation signal, perform amplitude adjustment and low-noise amplification on the received radar radiation signal, and mix frequency with the local oscillator signal of the broadband local oscillator module to the digital frequency storage station. The desired frequency band is output to the target delay digital frequency storage module.

Preferably, the target delay digital frequency storage module is used to delay the distance of the target, and is used to simulate the appearance distance of the moving target under different antenna scanning periods of the radar; The time delay value of the tested radar transmit pulse; under the synchronization of the tested radar transmit signal detection pulse, the control module reads the corresponding intermediate frequency pulse signal stored in the digital radio frequency memory according to the time delay value, and simulates the return of each target corresponding to different distances. Wave.

Preferably, the Doppler signal generation module is used to perform Doppler modulation on the target echo information; the control module calculates the required Doppler signal frequency according to the target speed and the tested radar signal carrier frequency, and controls the direct digital The frequency synthesizer generates two-way Doppler signals in quadrature; the distance-modulated IF digital signal output by the target delay digital frequency storage module is formed into a quadrature signal by the I/Q quadrature decimator; the I/Q two-way intermediate frequency The digital signal and the orthogonal two-way Doppler signals generated by the direct digital frequency synthesizer are orthogonally mixed, and the final output is the echo intermediate frequency signal after the Doppler frequency modulation.

Preferably, the instantaneous frequency measurement module is used to accurately measure the frequency of the signal output by the radar signal receiving and receiving frequency conversion module; the control module calculates the current radar radiation signal under test according to the frequency of the broadband local oscillator module and the output of the instantaneous frequency measurement module frequency to calculate the Doppler frequency of the simulated target.

Preferably, the signal amplitude and broadband power amplifier module is used to realize the modulation of the target signal amplitude, restore the analog target intermediate frequency signal output by the range delay and Doppler modulation to the original signal frequency of the radar under test, and then The simulated target signal is amplified to the required power level and transmitted to generate a hypersonic radio frequency target signal, which is received by the radar. The programmable attenuator is controlled to achieve accurate simulation of the target signal amplitude.

Preferably, the broadband local oscillator module is used to generate the frequency mixing local oscillator signal required by the receiving down-conversion circuit and the transmitting up-conversion circuit according to the operating frequency of the radar signal under test.

Preferably, the control module, according to the parameters of the tested radar and the simulated target, generates the current time delay value of the simulated target in real time and transmits it to the target delay digital frequency storage module to realize the distance modulation of the simulated target; The output of the frequency measurement module calculates the frequency of the radar signal under test, and generates the Doppler frequency shift of the simulated target in real time and transmits it to the Doppler signal generation module to realize the Doppler modulation of the simulated target signal; generate the control of signal amplitude modulation The parameters are transmitted to the signal amplitude and broadband power amplifier modules to achieve accurate simulation of the target signal amplitude; and the corresponding modules are controlled in real time.

Preferably, the signal amplitude and broadband power amplifier module is implemented by a high-speed radio frequency program-controlled attenuator to modulate the target signal amplitude.

Preferably, the Doppler modulation is controlled by the signal processing circuit, and the Doppler frequency modulation signal output by the signal processing circuit is up-converted to a center frequency of 1.5 GHz as the signal amplitude and the local oscillator signal of the broadband power amplifier module.

The hypersonic radio frequency analog target signal generated by the invention has obvious characteristics and is easy to be received and measured by radar; it adopts a wide-band system design to achieve a frequency coverage range of 2-18 GHz; it can simulate a target whose maximum relative radial velocity reaches Mach 13, and can be used The detection performance and effectiveness evaluation of radar for hypersonic targets.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic structural diagram of a hypersonic target radio frequency simulation system of the present invention;

Figure 2 is a schematic diagram of a simulated target delay;

Fig. 3 is a schematic diagram of the realization of digital Doppler modulation technology;

FIG. 4 is a schematic diagram of Doppler frequency shift synthesis.

Detailed ways

The following embodiments will describe the present invention in detail with reference to the accompanying drawings. In the drawings or descriptions, similar or identical parts use the same reference numerals, and in practical applications, the shape, thickness or height of each component can be enlarged or reduced. The embodiments listed in the present invention are only used to illustrate the present invention, but not to limit the scope of the present invention. Any obvious modifications or changes made to the present invention do not depart from the spirit and scope of the present invention.

As shown in Figure 1, the present invention provides a hypersonic broadband radio frequency target simulation system, including: a radar signal receiving frequency conversion module, a target delay digital frequency storage module, a Doppler signal generation module, an instantaneous frequency measurement module, a signal amplitude module And broadband power amplifier module, broadband local oscillator module, control module. The invention can precisely control the distance variation, Doppler frequency shift and amplitude variation characteristics of the radio frequency simulation target to generate the hypersonic radio frequency simulation target, which is consistent with the real hypersonic moving target. The implementation functions of each module are as follows:

The radar signal receiving frequency conversion module is used to receive the radar radiation signal, adjust the amplitude of the received radar radiation signal, amplify the low noise, and mix the local oscillator signal of the broadband local oscillator module to the frequency band required by the digital storage frequency. , output to the target delay digital frequency storage module.

The target delay digital frequency storage module is used to delay the distance of the target. The purpose of the delay is to simulate the appearance distance of the moving target under different antenna scanning periods of the radar. The control module calculates the next appearance distance of the simulated target according to the movement speed and time difference of the target, and converts it into a delay time. In the system of the present invention, the appearance distance of the simulated radio frequency target echo on the radar screen must be strictly controlled so that it can be recorded and tracked by the radar. To do this, a high-precision range delay must be applied to the range of the simulated target. In order to realize the time delay (distance) simulation of the analog echo signal of the broadband frequency agile radar, the broadband digital frequency storage circuit is used to realize it. According to the position of the simulated target, the control module calculates the time delay value of the echo signal of the simulated target relative to the radar transmission pulse under test; under the synchronization of the detection pulse of the radar transmission signal under test, the control module reads the data stored in the digital radio frequency memory according to the time delay value. The corresponding intermediate frequency pulse signal accurately simulates each target echo corresponding to different distances (delay values), as shown in Figure 2.

The Doppler signal generation module is used to perform Doppler modulation on the target echo information. The Doppler signal generation module uses digital algorithms to realize the frequency modulation of the radar signal, instead of the traditional use of microwave devices such as mixers and filters to realize the frequency modulation of the analog signal. The specific implementation method is shown in Figure 3: The control module calculates the required Doppler signal frequency according to the target speed and the carrier frequency of the radar signal under test, and controls the direct digital frequency synthesizer to generate two orthogonal Doppler signals. ; The distance modulated intermediate frequency digital signal output by the target delay digital frequency storage module is formed into a quadrature signal by the I/Q quadrature decimator; the I/Q two-way intermediate frequency digital signal and the quadrature generated by the direct digital frequency synthesizer are The two channels of Doppler signals obtained are subjected to quadrature mixing, and the final output is the echo intermediate frequency signal after Doppler frequency modulation.

The simulation accuracy of the Doppler frequency depends on the selection accuracy of the radar signal frequency. In order to realize the hypersonic target simulation of the frequency agile radar, an instantaneous frequency measurement module is added in the present invention to accurately measure the frequency of the signal output by the radar signal receiving and receiving frequency conversion module. The control module calculates the frequency of the current radar radiation signal under test according to the frequency of the broadband local oscillator module and the output of the instantaneous frequency measurement module, and accordingly can accurately calculate the Doppler frequency of the simulated target.

The instantaneous frequency measurement module is used to accurately measure the output signal (intermediate frequency signal) of the radar signal receiving frequency conversion module, and can accurately measure the frequency and phase information of the signal and transmit it to the control module.

Signal amplitude and broadband power amplifier module, the high-speed RF program-controlled attenuator with broadband and large dynamic range realizes the modulation of the target signal amplitude, and restores the analog target intermediate frequency signal output by range delay and Doppler modulation to the original target of the tested radar. At the signal frequency, the analog target signal is amplified to the required power level and transmitted to generate a hypersonic radio frequency target signal, which is received by the radar. The control module calculates the attenuation value at the current distance of the target in real time according to the initial distance and initial attenuation of the simulated target, and controls the programmable attenuator to achieve accurate simulation of the target signal amplitude.

The broadband local oscillator module is used to generate the mixing local oscillator signal required by the receiving down-conversion circuit and the transmitting up-conversion circuit according to the operating frequency of the radar signal under test.

The control module, according to the parameters of the tested radar and the simulated target, generates the current delay value of the simulated target in real time and transmits it to the target delay digital frequency storage module to realize the distance modulation of the simulated target; according to the frequency of the broadband local oscillator module and the instantaneous frequency measurement module The frequency of the radar signal under test is calculated from the output, and the Doppler frequency shift of the simulated target is generated in real time and transmitted to the Doppler signal generation module to realize the Doppler modulation of the simulated target signal; the control parameters for generating the signal amplitude modulation are transmitted to the Signal amplitude and broadband power amplifier module to achieve accurate simulation of target signal amplitude; and real-time control of corresponding modules.

In the hypersonic broadband radio frequency target simulation system of the present invention, the received radar signal is filtered and linearly amplified with low noise through the radar signal receiving frequency conversion module, and then mixed with the local oscillator signal generated by the broadband local oscillator module to obtain the intermediate frequency signal, It is output to the target delay digital frequency storage module, and the time delay value of the target is read in the control module to realize the simulation of the distance change of the hypersonic moving target; then the Doppler frequency shift modulation information is added through the Doppler signal generation module, The Doppler frequency shift value is also read from the control module to realize the speed simulation of the hypersonic radio frequency target; finally, the control module calculates the attenuation value at the current distance of the target in real time, and realizes the accurate signal amplitude of the target through the signal amplitude and broadband power amplifier module. Simulation; the instantaneous frequency measurement module accurately measures the frequency of the radar signal in real time, and provides the accurate radar radiation signal frequency for the target delay digital frequency storage module and the Doppler signal generation module through the control module, so as to realize the simulated hypersonic radio frequency target. The correlation of the signal with the radar signal under test.

The key of the present invention to simulate and generate a hypersonic radio frequency analog target signal lies in precisely controlling the three aspects of delay distance variation, Doppler frequency shift and signal amplitude variation characteristics of the radio frequency analog target signal. The purpose of the change of the delay distance is to simulate the change of the displacement of the moving target, and the purpose of adding the Doppler frequency shift (change in phase and frequency) to the simulated RF signal is to simulate the Doppler effect of the real high-speed moving target. The purpose of the amplitude change is to simulate the change of the signal energy received by the radar when the target is at different distances.

(1) Target distance simulation

In the system of the present invention, the appearance distance of the simulated radar echo on the radar screen must be strictly controlled in order to provide the radar with true value data. For this reason, it is necessary to carry out high-precision distance delay for the distance of the target, and the delay of distance can be equivalent to the delay of time in this system. The realization method is as follows: the purpose of the radar signal receiving frequency conversion module is to output an intermediate frequency signal (which is an analog signal), and the purpose of mixing the tested radar signal and reducing it to an intermediate frequency signal is to facilitate subsequent processing. The target delay digital frequency storage module digitally samples the intermediate frequency signal and converts it into a digital signal (the purpose of converting to a digital signal is to accurately control the delay time). After the analog signal is converted to a digital signal, the digital signal is sent to the time delay. The circuit extracts the envelope of the radar pulse signal, and uses the rising edge signal as the reference pulse of the detection pulse. Under the synchronization of the detection pulse of the radar transmission signal under test, the target delay digital frequency storage module calculates the analog target according to the control module. Delay value τn, read the intermediate frequency transmission pulse stored in the digital radio frequency memory, and accurately simulate the target echo corresponding to different delay values. The control module calculates the next appearance distance of the simulated target according to the movement speed and time difference of the simulated target, and converts it into a delay time τn.

(2) Simulation of target Doppler frequency shift

In addition to the range delay of the target, it is also necessary to perform Doppler modulation on the target echo information, and to add Doppler frequency shift at high speed in real time, in order to achieve hypersonic speed simulation. The realization method is: the output signal of the target delay digital frequency storage module is an intermediate frequency digital signal with a delay value (distance modulation) added, and the Doppler signal generation module first performs I/Q quadrature extraction on this intermediate frequency digital signal to form I intermediate frequency digital signal and Q intermediate frequency digital signal; as shown in Figure 3, the control module calculates the required Doppler signal frequency according to the set analog target speed and the carrier frequency of the radar signal under test, generates a frequency control word, and controls the direct digital frequency The synthesizer generates quadrature I-Doppler and Q-Doppler signals; the Doppler signal generation module then quadratures the I-IF digital signal and Q-IF digital signal with the I-Doppler and Q-Doppler signals Mixing, the final output is the echo intermediate frequency signal after Doppler frequency modulation.

The Doppler modulation circuit is controlled by the signal processing circuit, and up-converts the Doppler frequency modulation signal output by the signal processing circuit to the center frequency of 1.5GHz, which is used as the signal amplitude and the local oscillator signal of the broadband power amplifier module. The Doppler frequency shift range is -0.5MHz to 0.5MHz, which corresponds to a moving target with a relative radial velocity of Mach 13 that can be simulated when the radar operating frequency is 18GHz. The principle block diagram is shown in Figure 4. In the double frequency conversion process of the Doppler modulation circuit, a filter circuit design is added after the two frequency conversions to ensure that the spurious is less than -50dBc.

(3) Simulation of target intensity

In order to simulate the strength of the target echo signal, according to the technical parameters of the tested radar, the radar cross-sectional area of the simulated target, the distance from the target to the radar, the fluctuation characteristics of the target amplitude and other factors that affect the signal strength of the simulated RF target, the target echo is calculated. According to the intensity of the output signal of the radio frequency channel and the maximum effective radiated power of the system, calculate the attenuation value required to control the amplitude of the output signal, and control the attenuator in the radio frequency channel to make the echo reaching the radar receiving antenna under test. The signal strength is equal to the calculated value. This RF target signal simulation method can realistically simulate coherent and non-coherent target echo signals including pulse compression, frequency agility and pulse Doppler radar.

The analog target intermediate frequency signal output by the Doppler signal generation module has been subjected to range modulation and Doppler modulation. The signal amplitude and broadband power amplifier module mix the intermediate frequency signal with the local oscillator signal of the broadband local oscillator module to obtain a The same frequency as the radar signal, and then the signal is power amplified and transmitted to generate a hypersonic radio frequency target signal, which is received by the radar. The control module calculates the attenuation value at the current distance of the target in real time according to the initial distance and initial attenuation of the simulated target, and controls the signal amplitude and the programmable attenuator of the broadband power amplifier module to achieve accurate simulation of the target signal amplitude.

In addition, it should be understood that although this specification is described in terms of embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims (10)

1. a hypersonic broadband radio frequency target simulation system is characterized in that, comprising: radar signal receiving frequency conversion module, target delay digital frequency storage module, Doppler signal generation module, instantaneous frequency measurement module, signal amplitude and wideband power amplifier module, broadband local oscillator module, and control module; among them, The received radar signal is filtered and linearly amplified with low noise by the radar signal receiving and frequency conversion module, and then mixed with the local oscillator signal generated by the broadband local oscillator module to obtain an intermediate frequency signal, which is output to the target delay digital frequency storage module. The time delay value is read in the control module to simulate the distance change of the hypersonic moving target; then the Doppler frequency shift modulation information is added through the Doppler signal generation module, and the Doppler frequency shift value is also read from the control module Finally, the control module calculates the attenuation value at the current distance of the target in real time, and realizes the accurate simulation of the target signal amplitude through the signal amplitude and broadband power amplifier module; the instantaneous frequency measurement module accurately measures the radar signal in real time The control module provides the target delay digital frequency storage module and the Doppler signal generation module with the precise radar radiation signal frequency under test, and realizes the correlation between the simulated hypersonic radio frequency target signal and the radar signal under test. 2. The hypersonic broadband radio frequency target simulation system according to claim 1, wherein the radar signal receiving frequency conversion module is used for receiving the radiation signal of the radar, and performing amplitude adjustment and low noise on the received radar radiation signal. Amplify, mix with the local oscillator signal of the broadband local oscillator module to the frequency band required by the digital frequency storage, and output to the target delay digital storage frequency module. 3. hypersonic broadband radio frequency target simulation system as claimed in claim 1, is characterized in that, target delay digital frequency storage module, is used to carry out distance delay to target, is used for simulating moving target under different antenna scanning cycles of radar According to the position of the simulated target, the control module calculates the delay value of the echo signal of the simulated target relative to the radar transmission pulse under test; under the synchronization of the detection pulse of the radar transmission signal under test, the control module reads the digital signal according to the delay value. The corresponding intermediate frequency pulse signal stored in the radio frequency memory simulates each target echo corresponding to different distances. 4. The hypersonic broadband radio frequency target simulation system according to claim 1, wherein the Doppler signal generation module is used to perform Doppler modulation on the target echo information; The radar signal carrier frequency calculates the required Doppler signal frequency, and controls the direct digital frequency synthesizer to generate two orthogonal Doppler signals; the range-modulated intermediate frequency digital signal output by the target delay digital frequency storage module is processed by The I/Q quadrature decimator forms a quadrature signal; the I/Q two-way IF digital signal and the two-way Doppler signal in quadrature generated by the direct digital frequency synthesizer are subjected to quadrature mixing, and the final output is a multi-channel The echo IF signal after Peller frequency modulation. 5. The hypersonic broadband radio frequency target simulation system of claim 1, wherein the instantaneous frequency measurement module is used to accurately measure the signal frequency output by the radar signal receiving and receiving frequency conversion module; the control module is based on the broadband local oscillator. The frequency of the module and the output of the instantaneous frequency measurement module are used to calculate the frequency of the current radar radiation signal under test to calculate the Doppler frequency of the simulated target. 6. hypersonic broadband radio frequency target simulation system as claimed in claim 1, is characterized in that, signal amplitude and wideband power amplifier module, for realizing the modulation to target signal amplitude, will be output through distance delay and Doppler modulation The IF signal of the simulated target is restored to the original signal frequency of the tested radar, and then the simulated target signal is amplified to the required power level and transmitted to generate a hypersonic radio frequency target signal, which is received by the radar; Initial distance and initial attenuation, calculate the attenuation value at the current distance of the target in real time, and control the program-controlled attenuator to achieve accurate simulation of the target signal amplitude. 7. The hypersonic broadband radio frequency target simulation system according to claim 1, wherein the broadband local oscillator module is used to generate the required down-conversion circuit for receiving and transmitting the up-conversion circuit according to the operating frequency of the tested radar signal. The mixed local oscillator signal. 8. The hypersonic broadband radio frequency target simulation system according to claim 1, wherein the control module, according to the tested radar and the simulated target parameters, generates the current delay value of the simulated target in real time and transmits it to the target delay digital storage. The frequency module is used to realize the distance modulation of the simulated target; the frequency of the radar signal under test is calculated according to the frequency of the broadband local oscillator module and the output of the instantaneous frequency measurement module, and the Doppler frequency shift of the simulated target is generated in real time and transmitted to the Doppler signal generation. The module realizes the Doppler modulation of the analog target signal; the control parameters that generate the signal amplitude modulation are transmitted to the signal amplitude and broadband power amplifier module to realize the accurate simulation of the target signal amplitude; and the corresponding modules are controlled in real time. 9 . The hypersonic broadband radio frequency target simulation system according to claim 1 , wherein the signal amplitude and the broadband power amplifier module are modulated to the target signal amplitude by a high-speed radio frequency program-controlled attenuator. 10 . 10. The hypersonic broadband radio frequency target simulation system according to claim 3, wherein the Doppler modulation is controlled by the signal processing circuit, and the Doppler frequency modulation signal output by the signal processing circuit is up-converted to 1.5GHz The center frequency is used as the signal amplitude and the local oscillator signal of the broadband power amplifier module.

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