WO2021259011A1 - 基于光子分数傅立叶变换器的雷达信号处理方法、系统及装置 - Google Patents

基于光子分数傅立叶变换器的雷达信号处理方法、系统及装置 Download PDF

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WO2021259011A1
WO2021259011A1 PCT/CN2021/097466 CN2021097466W WO2021259011A1 WO 2021259011 A1 WO2021259011 A1 WO 2021259011A1 CN 2021097466 W CN2021097466 W CN 2021097466W WO 2021259011 A1 WO2021259011 A1 WO 2021259011A1
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signal
target
modulator
fractional fourier
electro
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PCT/CN2021/097466
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French (fr)
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郑小平
韩冠宇
李尚远
薛晓晓
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清华大学
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/26—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
    • G01S13/28—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses
    • G01S13/284—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses using coded pulses
    • G01S13/288—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses using coded pulses phase modulated
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/35—Details of non-pulse systems
    • G01S7/352—Receivers
    • G01S7/356—Receivers involving particularities of FFT processing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G01S13/343—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using sawtooth modulation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/285—Receivers
    • G01S7/292—Extracting wanted echo-signals
    • G01S7/2923—Extracting wanted echo-signals based on data belonging to a number of consecutive radar periods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/35—Details of non-pulse systems
    • G01S7/352—Receivers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/35—Details of non-pulse systems
    • G01S7/352—Receivers
    • G01S7/358—Receivers using I/Q processing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • This application relates to the technical field of signal processing, and in particular to a radar signal processing method, system and device based on a photon fractional Fourier transformer.
  • Fractional Fourier transform is one of the important means of signal processing. This method can convert a wideband non-stationary signal into a narrowband stationary signal in the fractional domain by rotating the time-frequency plane, so it is widely used in the fields of radar, communication, and sonar signal processing.
  • the traditional fractional Fourier transform based on electrical sampling and digital signal processing has problems such as limited bandwidth of electronic sampling equipment, severe electromagnetic interference, and huge amount of data for digital signal processing, and it has been difficult to meet the increasing demand for fast signal processing. Due to the characteristics of microwave photonics technology in high frequency, broadband and anti-electromagnetic interference, the signal processing method based on photonics has the advantages of large bandwidth and high center frequency.
  • targets are usually non-cooperative, and their number and location are unknown. Therefore, in the scenario of multiple non-cooperative targets, the interaction between multiple echoes due to the nonlinear effect of the modulator and photodetector causes the appearance of false target components in the fractional domain spectrum, and the amplitude and position of the false target are different from each other. The real target is close and difficult to distinguish.
  • This application aims to solve one of the technical problems in the related technology at least to a certain extent.
  • the first purpose of this application is to propose a radar signal processing method based on the photon fractional Fourier transformer, which can convert high-frequency broadband radar signals into low-frequency narrowband fractional domain signals and eliminate false target component pairs. Interference from radar detection results.
  • the second purpose of this application is to propose a radar signal processing system based on the photon fractional Fourier transformer.
  • the third purpose of this application is to propose a radar signal processing device based on the photon fractional Fourier transformer.
  • an embodiment of the present application proposes a radar signal processing method based on a photon fractional Fourier transformer, which includes:
  • Transmit a chirp signal to the target to be measured receive an echo signal of the target to be measured, and load the chirp signal and the echo signal on a single-frequency light wave through an electro-optical modulator;
  • the Fourier transform of the photocurrent is performed to obtain a fractional Fourier spectrum, and the distance information of the target to be measured is obtained according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the radar signal processing method based on the photon fractional Fourier transformer of the embodiment of the present application transmits a chirp signal to the target to be measured and receives the echo signal of the target to be measured, and loads the chirp signal and the echo signal through the electro-optical modulator On the single-frequency light wave; bias the sub-modulator and the mother modulator of the electro-optic modulator at different bias points, and modulate the single-frequency light wave through the electro-optic modulator, and output the modulated optical signal; through photodetection
  • the device converts the optical signal to obtain the photocurrent; performs Fourier transform on the photocurrent to obtain the fractional Fourier spectrum, and obtains the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the high-frequency broadband radar signal is converted into a low-frequency narrowband fractional domain signal, and the interference of false target components on the radar detection result is eliminated.
  • the chirp signal is:
  • f 0 is the initial frequency of the chirp signal used
  • k is the chirp rate of the chirp wave used
  • the echo signal is:
  • r i is the amplitude of the echo from the i-th target
  • ⁇ i is the delay of the echo from the i-th target
  • n is the number of targets.
  • separately biasing the electro-optic modulators at different bias points further includes:
  • the two sub-modulators and the mother modulator of the dual-parallel electro-optical modulator are respectively biased at the quadrature bias point, the suppressed carrier point and the maximum transmission point.
  • the object to be measured obtained based on the peak position of the respective pulse signals fractional Fourier spectrum distance information L i is:
  • Li is the distance between the i-th target and the chirp signal emission point
  • f i ' is the peak position of the i-th target in the fractional Fourier spectrum
  • c is the speed of light
  • ⁇ i is the distance from the i-th target
  • the delay of the echo, k is the chirp rate of the chirp used.
  • the embodiment of the second aspect of the present application proposes a radar signal processing system based on a photon fractional Fourier transformer, which includes: a radar transmitter, a radar receiver, a single frequency light source, an electro-optic modulator, and a bias point control Module, photodetector, digital signal processing module;
  • the radar transmitter is used to transmit a chirp signal to the target to be measured
  • the radar receiver is used to receive the echo signal of the target to be measured
  • the single-frequency light source is used to generate a single-frequency light wave and input it to the electro-optic modulator;
  • the bias point control module is used to bias the sub-modulator and the mother modulator of the electro-optic modulator at different bias points;
  • the input end of the electro-optical modulator inputs the single-frequency light wave, the chirp signal, and the echo signal, and the output end is connected to the input end of the photodetector, and is used to input the single frequency light wave, the chirp signal, and the echo signal according to the chirp signal and the echo signal.
  • the echo signal modulates the single-frequency light wave, and sends the modulated light signal to the photodetector;
  • the output terminal of the photodetector is connected to the input terminal of the digital signal processing module, and is used to convert the optical signal into a photocurrent, and send the photocurrent to the digital signal processing module;
  • the digital signal processing module is configured to perform Fourier transform on the photocurrent to obtain a fractional Fourier spectrum, and obtain distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the electro-optical modulator includes: a single-channel dual-parallel modulator and a dual-polarization dual-parallel Mach-Zehnder modulator.
  • a chirp signal is transmitted to the target to be measured through the radar transmitter, the echo signal of the target to be measured is received through the radar receiver, and the signal is generated by a single frequency light source.
  • Single-frequency light waves, and the sub-modulator and the mother modulator of the electro-optical modulator are respectively biased at different bias points through the bias point control module; then, the electro-optical modulator adjusts the single-frequency light waves according to the chirp signal and echo signal It modulates and sends the modulated optical signal to the photodetector.
  • the photodetector converts the optical signal to obtain the photocurrent; finally, the digital signal processing module performs Fourier transform on the photocurrent to obtain the fractional Fourier spectrum, according to The peak position of each pulse signal in the fractional Fourier spectrum obtains the distance information of the target to be measured.
  • high-frequency broadband radar signals can be converted into low-frequency narrowband fractional domain signals, and the interference of false target components on radar detection results can be eliminated.
  • a small number of radio frequency electrical and optical devices are used, the system structure is simple and compact, the modulator bias point is fixed, and it is not affected by the number and characteristics of targets, and can be applied to complex detection scenarios of multiple non-cooperative targets.
  • an embodiment of the third aspect of the present application proposes a radar signal processing device based on a photon fractional Fourier transformer, including:
  • the input module is used to transmit a chirp signal to the target under test and receive the echo signal of the target under test, and load the chirp signal and the echo signal on a single frequency light wave through an electro-optical modulator;
  • the modulation module is used to bias the sub-modulator and the mother modulator of the electro-optic modulator at different bias points respectively, and modulate the single-frequency light wave through the electro-optic modulator, and output the modulated light Signal;
  • the conversion module is used to convert the optical signal through a photodetector to obtain a photocurrent
  • the processing module is configured to perform Fourier transform on the photocurrent to obtain a fractional Fourier spectrum, and obtain the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the chirp signal is:
  • f 0 is the initial frequency of the chirp signal used
  • k is the chirp rate of the chirp wave used
  • the echo signal is:
  • r i is the amplitude of the echo from the i-th target
  • ⁇ i is the delay of the echo from the i-th target
  • n is the number of targets.
  • separately biasing the electro-optic modulators at different bias points further includes:
  • the two sub-modulators and the mother modulator of the dual-parallel electro-optical modulator are respectively biased at the quadrature bias point, the suppressed carrier point and the maximum transmission point.
  • the object to be measured obtained based on the peak position of the respective pulse signals fractional Fourier spectrum distance information L i is:
  • Li is the distance between the i-th target and the chirp signal emission point
  • f i ' is the peak position of the i-th target in the fractional Fourier spectrum
  • c is the speed of light
  • ⁇ i is the distance from the i-th target
  • the delay of the echo, k is the chirp rate of the chirp used.
  • the radar signal processing device based on the photon fractional Fourier transformer of the embodiment of the present application transmits a chirp signal to the target to be measured and receives the echo signal of the target to be measured, and loads the chirp signal and the echo signal through the electro-optical modulator On the single-frequency light wave; bias the sub-modulator and the mother modulator of the electro-optic modulator at different bias points, and modulate the single-frequency light wave through the electro-optic modulator, and output the modulated optical signal; through photodetection
  • the device converts the optical signal to obtain the photocurrent; performs Fourier transform on the photocurrent to obtain the fractional Fourier spectrum, and obtains the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the high-frequency broadband radar signal is converted into a low-frequency narrowband fractional domain signal, and the interference of false target components on the radar detection result is eliminated.
  • a small number of radio frequency electrical and optical devices are used, the system structure is simple and compact, the modulator bias point is fixed, and it is not affected by the number and characteristics of targets, and can be applied to complex detection scenarios of multiple non-cooperative targets.
  • Fig. 1 is a flowchart of a radar signal processing method based on a photon fractional Fourier transformer according to an embodiment of the application;
  • Fig. 2 is a structural diagram of a photon fractional Fourier transformer according to an embodiment of the application
  • Fig. 3 is a physical diagram of a dual-target detection experiment according to an application embodiment
  • FIG. 4 is a schematic diagram of detection results in which two sub-modulators of the dual-parallel modulator are biased at the suppressed carrier point according to an embodiment of the application;
  • FIG. 5 is a schematic diagram of detection results of two sub-modulators of the dual-parallel modulator respectively offset at a quadrature bias point and a suppressed carrier point according to an embodiment of the application;
  • FIG. 6 is a schematic structural diagram of a radar signal processing system based on a photon fractional Fourier transformer according to an embodiment of the application;
  • FIG. 7 is a working principle diagram of a photon fractional Fourier transformer for radar non-false target detection according to an embodiment of the application.
  • FIG. 8 is a schematic structural diagram of a photon fractional Fourier transformer based on a dual-parallel Mach-Zehnder modulator according to an embodiment of the application;
  • FIG. 9 is a schematic structural diagram of an I/Q photon fractional Fourier transformer based on a dual-polarization dual-parallel Mach-Zehnder modulator according to an embodiment of the application;
  • Fig. 10 is a schematic structural diagram of a radar signal processing device based on a photon fractional Fourier transformer according to an embodiment of the application.
  • Fig. 1 is a flowchart of a radar signal processing method based on a photon fractional Fourier transformer according to an embodiment of the application.
  • the radar signal processing method based on the photon fractional Fourier transformer includes the following steps:
  • Step S1 Transmit a chirp signal to the target to be measured and receive the echo signal of the target to be measured, and load the chirp signal and the echo signal on the single-frequency light wave through the electro-optic modulator.
  • a radar transmitter can be used to transmit a chirp signal to the target to be measured within the detection range, and the chirp signal will generate an echo signal when it hits the target to be measured, which is then received by the radar receiver.
  • the transmitted chirp signal is:
  • f 0 is the initial frequency of the chirp signal used
  • k is the chirp rate of the chirp wave used
  • the received echo signal is:
  • r i is the amplitude of the echo from the i-th target
  • ⁇ i is the delay of the echo from the i-th target
  • n is the number of targets.
  • the single-frequency light wave in the embodiment of the present application is generated by a single-frequency light source, the single-frequency light wave is input into the electro-optic modulator, and the chirp signal and the echo signal are simultaneously input into the electro-optic modulator.
  • Step S2 bias the sub-modulator and the mother modulator of the electro-optical modulator at different bias points respectively, modulate the single-frequency light wave by the electro-optical modulator, and output the modulated optical signal.
  • the electro-optical modulator is a double-parallel modulator
  • the two sub-modulators and the mother modulator of the double-parallel modulator are respectively biased at the quadrature bias point, the suppressed carrier point and the maximum transmission point.
  • the corresponding phase offset is:
  • step S3 the optical signal is converted by the photodetector to obtain the photocurrent.
  • the optical signal can be output through the modulation of the electro-optical modulator, and the optical signal is input into the photodetector to convert the optical signal into a photocurrent.
  • Step S4 Perform Fourier transform on the photocurrent to obtain a fractional Fourier spectrum, and obtain the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the obtained photocurrent is subjected to Fourier transform to obtain the fractional Fourier spectrum without false targets.
  • the distance information of the target can be obtained according to the following formula:
  • Li is the distance between the i-th target and the chirp signal emission point
  • f i ' is the peak position of the i-th target in the fractional Fourier spectrum
  • c is the speed of light
  • ⁇ i is the echo from the i-th target
  • K is the chirp rate of the chirp used.
  • the radar transmitter and radar receiver used in the embodiments of the present application can be integrated in the same device, and the obtained target position information can be regarded as the distance from the chirp signal transmitting point, or the distance from the receiving echo signal. distance.
  • the radar signal used in the experiment is X-band (8-12GHz), which is generated by an arbitrary waveform generator.
  • the generated signal is divided into two channels, one channel is electrically amplified and filtered and then enters the transmitting antenna for target detection, and the other channel is input into one of the microwave input ports of the dual-parallel modulator.
  • the echo of the target is received by the receiving antenna, amplified by the low-noise amplifier, and then input into the other microwave input port of the bi-parallel modulator.
  • the bias point control circuit controls the three bias points of the dual parallel modulator.
  • the output light signal of the double-parallel modulator is detected by the photodetector to generate a photocurrent. After sampling and digital signal processing by a digital oscilloscope, the target distance information within the detection range can be obtained.
  • the physical map of the dual-target detection experiment is shown in Figure 3. The two targets are placed at a distance of 90cm and 175cm from the antenna.
  • Figure 4 shows the detection results of the two sub-modulators of the dual-parallel modulator biased at the suppressed carrier point. Without spectral processing, it can be found that there are false targets at 85cm.
  • Figure 5 shows the detection results of the dual-parallel modulator with MZM1 bias at the quadrature bias point and MZM2 bias at the suppressed carrier point. After spectral processing, it can be found that the false target can be eliminated while the real target is retained.
  • the chirp signal is transmitted to the target to be measured, and the echo signal of the target to be measured is received, and the chirp signal and the echo are combined through the electro-optical modulator.
  • the signal is loaded on the single-frequency light wave; the sub-modulator and the mother modulator of the electro-optic modulator are respectively biased at different bias points, and the single-frequency light wave is modulated by the electro-optic modulator, and the modulated optical signal is output;
  • the photodetector converts the optical signal to obtain the photocurrent; performs Fourier transform on the photocurrent to obtain the fractional Fourier spectrum, and obtains the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the high-frequency broadband radar signal is converted into a low-frequency narrowband fractional domain signal, and the interference of false target components on the radar detection result is eliminated.
  • Fig. 6 is a schematic structural diagram of a radar signal processing system based on a photon fractional Fourier transformer according to an embodiment of the application.
  • the radar signal processing system based on the photon fractional Fourier transformer includes: radar transmitter, radar receiver, single-frequency light source, electro-optic modulator, bias point control module, photodetector, digital signal processing module .
  • the radar transmitter is used to transmit a chirp signal to the target to be measured
  • the radar receiver is used to receive the echo signal of the target to be measured
  • the single-frequency light source is used to generate a single-frequency light wave and input it to the electro-optic modulator;
  • the bias point control module is used to bias the sub-modulator and the mother modulator of the electro-optic modulator at different bias points;
  • the input end of the electro-optic modulator inputs single-frequency light waves, chirp signals and echo signals, and the output end is connected to the input end of the photodetector, which is used to modulate the single-frequency light waves according to the chirp signals and echo signals, and modulate The obtained optical signal is sent to the photodetector;
  • the output terminal of the photodetector is connected with the input terminal of the digital signal processing module, and is used to convert the optical signal into a photocurrent, and send the photocurrent to the digital signal processing module;
  • the digital signal processing module is used to perform Fourier transform on the photocurrent to obtain the fractional Fourier spectrum, and obtain the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the other devices can be integrated in one device, and the system structure is simple and compact.
  • the signal processing module can be realized by a computer.
  • Figure 7 it is the working principle of the photon fractional Fourier transformer for radar detection without false targets.
  • Figure 8 is a single Channel structure, one of the dual-parallel modulators
  • Figure 9 shows the I/Q photon fractional Fourier transformer structure based on the dual-polarization dual-parallel Mach-Zehnder modulator, which is the extended structure of Figure 8, which can realize I/Q reception, including A 50:50 electrical power splitter, a 90° bridge, a dual-polarization dual-parallel modulator, a polarization beam splitter, and 2 photodetectors.
  • the transmitted signal and the received signal of the I/Q structure in Figure 9 are divided into two channels after passing through a 90° bridge and a power splitter respectively, and are respectively input into the two sub-parallel modulators of the dual-polarization dual-parallel modulator, the dual-polarization dual-parallel
  • the output of the modulator is connected to the input of the polarization beam splitter, and the two output ports of the polarization beam splitter are each connected to a photodetector.
  • the modulation rate of the electro-optic modulator is greater than the maximum frequency of the radar signal; the maximum frequency of the electrical power divider should be greater than the maximum frequency of the radar signal; the maximum frequency of the 90° electric bridge should be greater than the maximum frequency of the radar signal ; The response rate of the photodetector is greater than the bandwidth of the radar signal.
  • the high frequency broadband radar signal can be converted into a low frequency narrowband fractional domain signal, and the interference of false target components on the radar detection result can be eliminated.
  • a small number of radio frequency electrical and optical devices are used, the system structure is simple and compact, the modulator bias point is fixed, and it is not affected by the number and characteristics of targets, and can be applied to complex detection scenarios of multiple non-cooperative targets.
  • Fig. 10 is a schematic structural diagram of a radar signal processing device based on a photon fractional Fourier transformer according to an embodiment of the application.
  • the radar signal processing device based on the photon fractional Fourier transformer includes: an input module 100, a modulation module 200, a conversion module 300, and a processing module 400.
  • the input module 100 is used to transmit a chirp signal to the target to be measured and receive the echo signal of the target to be measured, and load the chirp signal and the echo signal on the single-frequency light wave through the electro-optical modulator.
  • the modulation module 200 is used to bias the sub-modulator and the mother modulator of the electro-optical modulator at different bias points respectively, modulate the single-frequency light wave through the electro-optical modulator, and output the modulated optical signal.
  • the conversion module 300 is used for converting the optical signal through the photodetector to obtain the photocurrent.
  • the processing module 400 is configured to perform Fourier transform on the photocurrent to obtain a fractional Fourier spectrum, and obtain the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the chirp signal is:
  • f 0 is the initial frequency of the chirp signal used
  • k is the chirp rate of the chirp wave used
  • the echo signal is:
  • r i is the amplitude of the echo from the i-th target
  • ⁇ i is the delay of the echo from the i-th target
  • n is the number of targets.
  • separately biasing the electro-optic modulators at different bias points further includes:
  • the two sub-modulators and the mother modulator of the dual-parallel electro-optic modulator are respectively biased at the quadrature bias point, the suppressed carrier point and the maximum transmission point.
  • the distance information L i of the target to be measured obtained according to the peak position of each pulse signal in the fractional Fourier spectrum is:
  • Li is the distance between the i-th target and the chirp signal emission point
  • f i ' is the peak position of the i-th target in the fractional Fourier spectrum
  • c is the speed of light
  • ⁇ i is the echo from the i-th target
  • K is the chirp rate of the chirp used.
  • the chirp signal is transmitted to the target to be measured, and the echo signal of the target to be measured is received, and the chirp signal and the echo are combined through the electro-optic modulator.
  • the signal is loaded on the single-frequency light wave; the sub-modulator and the mother modulator of the electro-optic modulator are respectively biased at different bias points, and the single-frequency light wave is modulated by the electro-optic modulator, and the modulated optical signal is output;
  • the photodetector converts the optical signal to obtain the photocurrent; performs Fourier transform on the photocurrent to obtain the fractional Fourier spectrum, and obtains the distance information of the target to be measured according to the peak position of each pulse signal in the fractional Fourier spectrum.
  • the high-frequency broadband radar signal is converted into a low-frequency narrowband fractional domain signal, and the interference of false target components on the radar detection result is eliminated.
  • first and second are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with “first” and “second” may explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality of” means at least two, such as two, three, etc., unless specifically defined otherwise.

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Abstract

一种基于光子分数傅立叶变换器的雷达信号处理方法、系统及装置，其中，雷达信号处理方法包括：向待测目标发射线性调频信号，并接收待测目标的回波信号，通过电光调制器将线性调频信号和回波信号加载在单频光波上（S1）；将电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过电光调制器对单频光波进行调制，并输出调制后的光信号（S2）；通过光电探测器将光信号进行转换得到光电流（S3）；对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息（S4）。实现了将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。

Description

基于光子分数傅立叶变换器的雷达信号处理方法、系统及装置 技术领域
本申请涉及信号处理技术领域，特别涉及一种基于光子分数傅立叶变换器的雷达信号处理方法、系统及装置。
背景技术
分数傅立叶变换是信号处理的重要手段之一。该方法通过时频平面旋转的方法可将宽带非平稳信号转换为分数域的窄带平稳信号，因此被广泛应用于雷达、通信、声纳信号处理领域。随着高精度高分辨雷达探测、高速率大容量无线通信等需求的发展，各个系统对于发射信号的带宽和中心频点的要求日益升高。传统基于电采样及数字信号处理的分数傅立叶变换由于存在着电子采样设备带宽受限、受电磁干扰严重，以及数字信号处理数据量巨大的问题，已难以满足日益增长的信号快速处理的需求。由于微波光子技术高频宽带、抗电磁干扰的特性，基于光子学的信号处理方法具有大带宽、高中心频点的优势。
在实际雷达探测场景中，目标通常是非合作的，其数目及位置是未知的。因此在多非合作目标场景下，由于调制器及光电探测器的非线性效应使得多个回波之间的相互作用，造成分数域频谱中假目标分量的出现，且假目标的幅度和位置与真实目标接近，难以区分。
发明内容
本申请旨在至少在一定程度上解决相关技术中的技术问题之一。
为此，本申请的第一个目的在于提出一种基于光子分数傅立叶变换器的雷达信号处理方法，该方法可将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。
本申请的第二个目的在于提出一种基于光子分数傅立叶变换器的雷达信号处理系统。
本申请的第三个目的在于提出一种基于光子分数傅立叶变换器的雷达信号处理装置。
为达到上述目的，本申请一方面实施例提出了一种基于光子分数傅立叶变换器的雷达信号处理方法，包括：
向待测目标发射线性调频信号，并接收所述待测目标的回波信号，通过电光调制器将所述线性调频信号和所述回波信号加载在单频光波上；
将所述电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过所述电光调 制器对所述单频光波进行调制，并输出调制后的光信号；
通过光电探测器将所述光信号进行转换得到光电流；
对所述光电流进行傅里叶变换得到分数傅里叶频谱，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到所述待测目标的距离信息。
本申请实施例的基于光子分数傅立叶变换器的雷达信号处理方法，通过向待测目标发射线性调频信号，并接收待测目标的回波信号，通过电光调制器将线性调频信号和回波信号加载在单频光波上；将电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过电光调制器对单频光波进行调制，并输出调制后的光信号；通过光电探测器将光信号进行转换得到光电流；对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。由此，将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。
可选地，在本申请的一个实施例中，所述线性调频信号为：
s 0(t)＝expj(2πf 0t+πkt 2)
其中，f 0为所用的线性调频信号的初始频率，k为所用的线性调频波的啁啾率；
所述回波信号为：
Figure PCTCN2021097466-appb-000001
其中，r i为来自第i个目标回波的幅度，τ i为来自第i个目标回波的延时，n为目标个数。
可选地，在本申请的一个实施例中，将所述电光调制器分别偏置在不同的偏置点进一步包括：
将所述双平行电光调制器的两个子调制器与母调制器分别偏置在正交偏置点、抑制载波点及最大传输点。
可选地，在本申请的一个实施例中，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息L i为：
L i＝τ ic/2＝|f i′c/2k|
其中，L i为第i个目标距离所述线性调频信号发射点的距离，f i'为第i个目标在分数傅里叶频谱的峰值位置，c为光速，τ i为来自第i个目标回波的延时，k为所用的线性调频波的啁啾率。
为达到上述目的，本申请第二方面实施例提出了一种基于光子分数傅立叶变换器的雷达信号处理系统，包括：雷达发射机、雷达接收机、单频光源、电光调制器、偏置点控制模块、光电探测器、数字信号处理模块；
所述雷达发射机用于向所述待测目标发射线性调频信号；
所述雷达接收机用于接收所述待测目标的回波信号；
所述单频光源用于生成单频光波并输入至所述电光调制器；
所述偏置点控制模块用于将所述电光调制器的子调制器与母调制器分别偏置在不同的偏置点；
所述电光调制器的输入端输入所述单频光波、所述线性调频信号和所述回波信号，输出端与所述光电探测器的输入端连接，用于根据所述线性调频信号和所述回波信号对所述单频光波进行调制，并将调制得到的光信号发送至所述光电探测器；
所述光电探测器的输出端与所述数字信号处理模块的输入端连接，用于将所述光信号转换为光电流，并将所述光电流发送至所述数字信号处理模块；
所述数字信号处理模块用于对所述光电流进行傅里叶变换得到分数傅里叶频谱，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。
可选地，在本申请的一个实施例中，所述电光调制器包括：单通道双平行调制器和双偏振双平行马赫曾德尔调制器。
本申请实施例的基于光子分数傅立叶变换器的雷达信号处理系统，首先，通过雷达发射机向待测目标发射线性调频信号，通过雷达接收机接收待测目标的回波信号，通过单频光源生成单频光波，和通过偏置点控制模块将电光调制器的子调制器与母调制器分别偏置在不同的偏置点；然后，电光调制器根据线性调频信号和回波信号对单频光波进行调制，并将调制得到的光信号发送至光电探测器，光电探测器将光信号进行转换得到光电流；最后，数字信号处理模块对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。由此，可将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。此外使用了少量的射频电器件及光器件，系统结构简单紧凑，调制器偏置点固定，不受目标数目及特性的影响，可应用于多非合作目标的复杂探测场景。
为达到上述目的，本申请第三方面实施例提出了一种基于光子分数傅立叶变换器的雷达信号处理装置，包括：
输入模块，用于向待测目标发射线性调频信号，并接收所述待测目标的回波信号，通过电光调制器将所述线性调频信号和所述回波信号加载在单频光波上；
调制模块，用于将所述电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过所述电光调制器对所述单频光波进行调制，并输出调制后的光信号；
转换模块，用于通过光电探测器将所述光信号进行转换得到光电流；
处理模块，用于对所述光电流进行傅里叶变换得到分数傅里叶频谱，根据所述分数傅 里叶频谱中各个脉冲信号的峰值位置得到所述待测目标的距离信息。
可选地，在本申请的一个实施例中，所述线性调频信号为：
s 0(t)＝expj(2πf 0t+πkt 2)
其中，f 0为所用的线性调频信号的初始频率，k为所用的线性调频波的啁啾率；
所述回波信号为：
Figure PCTCN2021097466-appb-000002
其中，r i为来自第i个目标回波的幅度，τ i为来自第i个目标回波的延时，n为目标个数。
可选地，在本申请的一个实施例中，将所述电光调制器分别偏置在不同的偏置点进一步包括：
将所述双平行电光调制器的两个子调制器与母调制器分别偏置在正交偏置点、抑制载波点及最大传输点。
可选地，在本申请的一个实施例中，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息L i为：
L i＝τ ic/2＝|f i′c/2k|
其中，L i为第i个目标距离所述线性调频信号发射点的距离，f i'为第i个目标在分数傅里叶频谱的峰值位置，c为光速，τ i为来自第i个目标回波的延时，k为所用的线性调频波的啁啾率。
本申请实施例的基于光子分数傅立叶变换器的雷达信号处理装置，通过向待测目标发射线性调频信号，并接收待测目标的回波信号，通过电光调制器将线性调频信号和回波信号加载在单频光波上；将电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过电光调制器对单频光波进行调制，并输出调制后的光信号；通过光电探测器将光信号进行转换得到光电流；对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。由此，将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。此外使用了少量的射频电器件及光器件，系统结构简单紧凑，调制器偏置点固定，不受目标数目及特性的影响，可应用于多非合作目标的复杂探测场景。
本申请附加的方面和优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本申请的实践了解到。
附图说明
本申请上述的和/或附加的方面和优点从下面结合附图对实施例的描述中将变得明显和容易理解，其中：
图1为根据申请实施例的基于光子分数傅立叶变换器的雷达信号处理方法流程图；
图2为根据申请实施例的光子分数傅立叶变换器的结构图；
图3为根据申请实施例的双目标探测实验的实物图；
图4为根据申请实施例的双平行调制器的两个子调制器均偏置在抑制载波点的探测结果示意图；
图5为根据申请实施例的双平行调制器的两个子调制器分别偏置在正交偏置点和抑制载波点的探测结果示意图；
图6为根据申请实施例的基于光子分数傅立叶变换器的雷达信号处理系统结构示意图；
图7为根据申请实施例的雷达无虚假目标探测的光子分数傅里叶变换器的工作原理图；
图8为根据申请实施例的基于双平行马赫曾德尔调制器的光子分数傅立叶变换器结构示意图；
图9为根据申请实施例的基于双偏振双平行马赫曾德尔调制器的I/Q光子分数傅立叶变换器结构示意图；
图10为根据申请实施例的基于光子分数傅立叶变换器的雷达信号处理装置结构示意图。
具体实施方式
下面详细描述本申请的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，旨在用于解释本申请，而不能理解为对本申请的限制。
下面参照附图描述根据本申请实施例提出的基于光子分数傅立叶变换器的雷达信号处理方法、系统及装置。
首先将参照附图描述根据本申请实施例提出的基于光子分数傅立叶变换器的雷达信号处理方法。
图1为根据申请实施例的基于光子分数傅立叶变换器的雷达信号处理方法流程图。
如图1所示，该基于光子分数傅立叶变换器的雷达信号处理方法包括以下步骤：
步骤S1，向待测目标发射线性调频信号，并接收待测目标的回波信号，通过电光调制器将线性调频信号和回波信号加载在单频光波上。
具体地，可以通过雷达发射机向探测范围内的待测目标发射线性调频信号，线性调频信号碰到待测目标后产生回波信号，再被雷达接收机接收。
在本申请实施例中，发射的线性调频信号为：
s 0(t)＝expj(2πf 0t+πkt 2)
其中，f 0为所用的线性调频信号的初始频率，k为所用的线性调频波的啁啾率；
接收到的回波信号为：
Figure PCTCN2021097466-appb-000003
其中，r i为来自第i个目标回波的幅度，τ i为来自第i个目标回波的延时，n为目标个数。
本申请实施例中的单频光波通过单频光源产生，将单频光波输入到电光调制器中，同时将线性调频信号和回波信号一同输入到电光调制器中。
步骤S2，将电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过电光调制器对单频光波进行调制，并输出调制后的光信号。
可以理解的是，通过控制电光调制器的偏置点进行光谱处理从而对分数域频谱进行操控，实现两个假目标分量来源的对消。
具体地，电光调制器为双平行调制器时，将双平行调制器的两个子调制器与母调制器分别偏置在：正交偏置点，抑制载波点及最大传输点。对应相位偏置为：
φ 1＝π/4,φ 2＝π/2,φ 3＝0
步骤S3，通过光电探测器将光信号进行转换得到光电流。
将电光调制器进行偏置后，通过电光调制器的调制可以输出光信号，将光信号输入到光电探测器中，将光信号转换为光电流。
步骤S4，对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。
具体地，将得到的光电流做傅里叶变换，即可得到无假目标的分数傅里叶频谱，根据分数傅里叶频谱中各脉冲信号的峰值位置按照下式得出目标的距离信息：
L i＝τ ic/2＝|f i′c/2k|
其中，L i为第i个目标距离线性调频信号发射点的距离，f i'为第i个目标在分数傅里叶频谱的峰值位置，c为光速，τ i为来自第i个目标回波的延时，k为所用的线性调频波的啁啾率。
具体地，本申请实施例中使用的雷达发射机和雷达接收机可以集成在同一装置中，得到的目标位置信息可以看作距离线性调频信号发射点的距离，也可以为距离接收回波信号的距离。
使用基于双平行调制器的光子分数傅立叶变换器，进行双目标探测实验，如图2所示， 在实验中所使用的雷达信号为X波段(8-12GHz)，由任意波形发生器产生。产生后信号分为两路，一路经电放大滤波后进入发射天线进行目标探测，一路输入双平行调制器其中的一个微波输入口。目标的回波经接收天线接收后经低噪声放大器放大后输入双平行调制器的另一个微波输入口。偏置点控制电路控制双平行调制器的三个偏置点。双平行调制器输出光信号经光电探测器探测后产生光电流，经数字示波器采样及数字信号处理后即可得到探测范围内的目标距离信息。双目标探测实验的实物图如图3所示，两个目标分别放置在距离天线90cm和175cm处。图4展示了双平行调制器的两个子调制器均偏置在抑制载波点的探测结果，未经过光谱处理，可以发现，在85cm处有假目标的出现。图5展示了双平行调制器的MZM1偏置在正交偏置点，MZM2偏置在抑制载波点的探测结果，在经过光谱处理后，可以发现假目标可以被消除，而真实目标得以保留。
根据本申请实施例提出的基于光子分数傅立叶变换器的雷达信号处理方法，通过向待测目标发射线性调频信号，并接收待测目标的回波信号，通过电光调制器将线性调频信号和回波信号加载在单频光波上；将电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过电光调制器对单频光波进行调制，并输出调制后的光信号；通过光电探测器将光信号进行转换得到光电流；对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。由此，将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。
其次参照附图描述根据本申请实施例提出的基于光子分数傅立叶变换器的雷达信号处理系统。
图6为根据申请实施例的基于光子分数傅立叶变换器的雷达信号处理系统结构示意图。
如图6所示，该基于光子分数傅立叶变换器的雷达信号处理系统包括：雷达发射机、雷达接收机、单频光源、电光调制器、偏置点控制模块、光电探测器、数字信号处理模块。
雷达发射机用于向待测目标发射线性调频信号；
雷达接收机用于接收待测目标的回波信号；
单频光源用于生成单频光波并输入至电光调制器；
偏置点控制模块用于将电光调制器的子调制器与母调制器分别偏置在不同的偏置点；
电光调制器的输入端输入单频光波、线性调频信号和回波信号，输出端与光电探测器的输入端连接，用于根据线性调频信号和回波信号对单频光波进行调制，并将调制得到的光信号发送至光电探测器；
光电探测器的输出端与数字信号处理模块的输入端连接，用于将光信号转换为光电流，并将光电流发送至数字信号处理模块；
数字信号处理模块用于对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里 叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。
可以理解的是，除信号处理模块外，其余器件可以集成在一个装置中，系统结构简单紧凑。信号处理模块可以通过计算机实现。
如图7所示，为雷达无虚假目标探测的光子分数傅里叶变换器的工作原理，其中，两种光子分数傅立叶变换器实现结构分别如图8和图9所示，其中图8为单通道结构，其中一个双平行调制器；图9展示了基于双偏振双平行马赫曾德尔调制器的I/Q光子分数傅立叶变换器结构，为图8的扩展结构，可实现I/Q接收，包括一个50：50电功分器，一个90°电桥，一个双偏振双平行调制器，一个偏振分束器，2个光电探测器。图8中的单通道结构发射信号与接收信号分别接入双平行调制器的两个射频输入接口，双平行调制器输出直接与光电探测器的输入相连。图9中的I/Q结构发射信号和接收信号分别经90°电桥和功分器后分为两路，分别输入双偏振双平行调制器的两个子双平行调制器中，双偏振双平行调制器的输出与偏振分束器的输入相连，偏振分束器的两个输出口各与一个光电探测器相连。
在本申请的实施例中，电光调制器的调制速率大于雷达信号的最大频率；电功分器的最大频率应大于雷达信号的最大频率；90°电桥的最大频率应大于雷达信号的最大频率；光电探测器的响应速率大于雷达信号带宽。
需要说明的是，前述对方法实施例的解释说明也适用于该实施例的系统，此处不再赘述。
根据本申请实施例提出的基于光子分数傅立叶变换器的雷达信号处理系统，可将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。此外使用了少量的射频电器件及光器件，系统结构简单紧凑，调制器偏置点固定，不受目标数目及特性的影响，可应用于多非合作目标的复杂探测场景。
其次参照附图描述根据本申请实施例提出的基于光子分数傅立叶变换器的雷达信号处理装置。
图10为根据申请实施例的基于光子分数傅立叶变换器的雷达信号处理装置结构示意图。
如图10所示，该基于光子分数傅立叶变换器的雷达信号处理装置包括：输入模块100、调制模块200、转换模块300和处理模块400。
输入模块100，用于向待测目标发射线性调频信号，并接收待测目标的回波信号，通过电光调制器将线性调频信号和回波信号加载在单频光波上。
调制模块200，用于将电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过电光调制器对单频光波进行调制，并输出调制后的光信号。
转换模块300，用于通过光电探测器将光信号进行转换得到光电流。
处理模块400，用于对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频 谱中各个脉冲信号的峰值位置得到待测目标的距离信息。
进一步地，在本申请实施例中，线性调频信号为：
s 0(t)＝expj(2πf 0t+πkt 2)
其中，f 0为所用的线性调频信号的初始频率，k为所用的线性调频波的啁啾率；
回波信号为：
Figure PCTCN2021097466-appb-000004
其中，r i为来自第i个目标回波的幅度，τ i为来自第i个目标回波的延时，n为目标个数。
进一步地，在本申请实施例中，将电光调制器分别偏置在不同的偏置点进一步包括：
将双平行电光调制器的两个子调制器与母调制器分别偏置在正交偏置点、抑制载波点及最大传输点。
进一步地，在本申请实施例中，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息L i为：
L i＝τ ic/2＝|f i′c/2k|
其中，L i为第i个目标距离线性调频信号发射点的距离，f i'为第i个目标在分数傅里叶频谱的峰值位置，c为光速，τ i为来自第i个目标回波的延时，k为所用的线性调频波的啁啾率。
需要说明的是，前述对方法、系统实施例的解释说明也适用于该实施例的装置，此处不再赘述。
根据本申请实施例提出的基于光子分数傅立叶变换器的雷达信号处理装置，通过向待测目标发射线性调频信号，并接收待测目标的回波信号，通过电光调制器将线性调频信号和回波信号加载在单频光波上；将电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过电光调制器对单频光波进行调制，并输出调制后的光信号；通过光电探测器将光信号进行转换得到光电流；对光电流进行傅里叶变换得到分数傅里叶频谱，根据分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。由此，将高频宽带雷达信号转化为低频窄带的分数域信号，并消除假目标分量对雷达探测结果的干扰。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本申请的描述中，“多个”的含义是至少两个，例如两个，三个等，除非另有明确具体的限定。
在本说明书的描述中，参考术语“一个实施例”、“一些实施例”、“示例”、“具体示例”、 或“一些示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本申请的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。此外，在不相互矛盾的情况下，本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。
尽管上面已经示出和描述了本申请的实施例，可以理解的是，上述实施例是示例性的，不能理解为对本申请的限制，本领域的普通技术人员在本申请的范围内可以对上述实施例进行变化、修改、替换和变型。

Claims (10)

  1. 一种基于光子分数傅立叶变换器的雷达信号处理方法，其特征在于，包括以下步骤：
    向待测目标发射线性调频信号，并接收所述待测目标的回波信号，通过电光调制器将所述线性调频信号和所述回波信号加载在单频光波上；
    将所述电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过所述电光调制器对所述单频光波进行调制，并输出调制后的光信号；
    通过光电探测器将所述光信号进行转换得到光电流；
    对所述光电流进行傅里叶变换得到分数傅里叶频谱，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到所述待测目标的距离信息。
  2. 根据权利要求1所述的基于光子分数傅立叶变换器的雷达信号处理方法，其特征在于，所述线性调频信号为：
    s 0(t)＝expj(2πf 0t+πkt 2)
    其中，f 0为所用的线性调频信号的初始频率，k为所用的线性调频波的啁啾率；
    所述回波信号为：
    Figure PCTCN2021097466-appb-100001
    其中，r i为来自第i个目标回波的幅度，τ i为来自第i个目标回波的延时，n为目标个数。
  3. 根据权利要求1所述的基于光子分数傅立叶变换器的雷达信号处理方法，其特征在于，将所述电光调制器分别偏置在不同的偏置点进一步包括：
    将所述双平行电光调制器的两个子调制器与母调制器分别偏置在正交偏置点、抑制载波点及最大传输点。
  4. 根据权利要求1所述的基于光子分数傅立叶变换器的雷达信号处理方法，其特征在于，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息L i为：
    L i＝τ ic/2＝|f i′c/2k|
    其中，L i为第i个目标距离所述线性调频信号发射点的距离，f i'为第i个目标在分数傅里叶频谱的峰值位置，c为光速，τ i为来自第i个目标回波的延时，k为所用的线性调频波的啁啾率。
  5. 一种基于光子分数傅立叶变换器的雷达信号处理系统，其特征在于，包括：雷达发射机、雷达接收机、单频光源、电光调制器、偏置点控制模块、光电探测器、数字信号处理模块；
    所述雷达发射机用于向所述待测目标发射线性调频信号；
    所述雷达接收机用于接收所述待测目标的回波信号；
    所述单频光源用于生成单频光波并输入至所述电光调制器；
    所述偏置点控制模块用于将所述电光调制器的子调制器与母调制器分别偏置在不同的偏置点；
    所述电光调制器的输入端输入所述单频光波、所述线性调频信号和所述回波信号，输出端与所述光电探测器的输入端连接，用于根据所述线性调频信号和所述回波信号对所述单频光波进行调制，并将调制得到的光信号发送至所述光电探测器；
    所述光电探测器的输出端与所述数字信号处理模块的输入端连接，用于将所述光信号转换为光电流，并将所述光电流发送至所述数字信号处理模块；
    所述数字信号处理模块用于对所述光电流进行傅里叶变换得到分数傅里叶频谱，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息。
  6. 根据权利要求5所述的基于光子分数傅立叶变换器的雷达信号处理系统，其特征在于，所述电光调制器包括：单通道双平行调制器和双偏振双平行马赫曾德尔调制器。
  7. 一种基于光子分数傅立叶变换器的雷达信号处理装置，其特征在于，包括：
    输入模块，用于向待测目标发射线性调频信号，并接收所述待测目标的回波信号，通过电光调制器将所述线性调频信号和所述回波信号加载在单频光波上；
    调制模块，用于将所述电光调制器的子调制器与母调制器分别偏置在不同的偏置点，通过所述电光调制器对所述单频光波进行调制，并输出调制后的光信号；
    转换模块，用于通过光电探测器将所述光信号进行转换得到光电流；
    处理模块，用于对所述光电流进行傅里叶变换得到分数傅里叶频谱，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到所述待测目标的距离信息。
  8. 根据权利要求7所述的基于光子分数傅立叶变换器的雷达信号处理装置，其特征在于，所述线性调频信号为：
    s 0(t)＝expj(2πf 0t+πkt 2)
    其中，f 0为所用的线性调频信号的初始频率，k为所用的线性调频波的啁啾率；
    所述回波信号为：
    Figure PCTCN2021097466-appb-100002
    其中，r i为来自第i个目标回波的幅度，τ i为来自第i个目标回波的延时，n为目标个数。
  9. 根据权利要求7所述的基于光子分数傅立叶变换器的雷达信号处理装置，其特征在于，将所述电光调制器分别偏置在不同的偏置点进一步包括：
    将所述双平行电光调制器的两个子调制器与母调制器分别偏置在正交偏置点、抑制载波点及最大传输点。
  10. 根据权利要求7所述的基于光子分数傅立叶变换器的雷达信号处理装置，其特征在于，根据所述分数傅里叶频谱中各个脉冲信号的峰值位置得到待测目标的距离信息L i为：
    L i＝τ ic/2＝|f i′c/2k|
    其中，L i为第i个目标距离所述线性调频信号发射点的距离，f i'为第i个目标在分数傅里叶频谱的峰值位置，c为光速，τ i为来自第i个目标回波的延时，k为所用的线性调频波的啁啾率。
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