Interference signal type and parameter determination method and system based on microwave photonics technology

Abstract

This invention discloses a method and system for determining the type and parameters of interference signals based on microwave photonics technology. The method utilizes microwave photonics technology to modulate broadband interference signals into the optical domain. By dynamically matching the LCT transform kernel function with the reference signal parameters, the LCT operation is directly performed in the analog domain, focusing the interference signal in the optimal LCT domain. Based on the time-frequency characteristics after focusing, real-time type judgment and parameter estimation of the interference signal are achieved, completely avoiding the digital domain iterative operations of existing electronic methods. The computational complexity is reduced to microseconds, and the parameter estimation delay reaches the microsecond level, without any broadband throughput bottleneck. The parameter tuning delay depends only on the control rate of the reference signal, adapting to the type identification and parameter estimation requirements of various types of broadband interference signals, such as linear frequency modulation, frequency hopping, slice combination, and intermittent sampling and forwarding. The resistance to environmental interference and stability are significantly enhanced.

Description

Technical Field

[0001] This invention relates to the field of interference signal sensing technology, and in particular to a method and system for determining interference signal type and parameters based on microwave photonics technology. Background Technology

[0002] In modern electronic warfare, radar detection, and high-speed communication systems, the widespread application of broadband jamming signals, such as slice combinations and spectral dispersion, based on digital radio frequency memory, poses a severe challenge to the anti-jamming capabilities of equipment. Rapidly and accurately identifying the type of jamming and precisely estimating the core parameters of broadband jamming signals, such as center frequency, bandwidth, frequency modulation, and jamming slice time, are prerequisites for achieving jamming suppression and anti-jamming response.

[0003] Currently, interference signal type identification and parameter estimation are mainly implemented using digital implementation in the electrical domain. However, this technology has significant limitations in broadband interference signal classification and parameter estimation scenarios: the digital implementation scheme has high computational complexity and struggles to balance the real-time performance of broadband signal processing with the accuracy of parameter estimation. (Invention Content)

[0004] This invention provides a method and system for determining the type and parameters of interference signals based on microwave photonics technology, which solves the technical problems of high computational complexity, insufficient real-time performance, and weak broadband adaptability in the prior art.

[0005] This invention provides a method for determining the type and parameters of interference signals based on microwave photonics technology, including:

[0006] The first electro-optic modulator receives the first optical carrier and the radar echo signal carrying interference, respectively, so as to realize the modulation of the first optical carrier by the radar echo signal, and input the modulated optical signal into the optical mixer.

[0007] The second electro-optic modulator receives the second optical carrier and the reference signal respectively, realizes the modulation of the second optical carrier by the reference signal, and inputs the modulated optical signal into the optical mixer;

[0008] The optical mixer enables orthogonal mixing of two modulated optical signals, and the orthogonally mixed optical signal is output to a balanced photodetector to achieve conjugate multiplication of the radar echo signal and the reference signal.

[0009] The balanced photodetector outputs an electrical signal to a spectrum analyzer, which outputs the type and parameters of the interference signal. Specifically, by adjusting the starting frequency and modulation slope of the reference signal to correspond to different transformation kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are the result of a linear canonical transformation.

[0010] Specifically, by adjusting the starting frequency and frequency modulation slope of the reference signal to correspond to different transform kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are linear canonical transform results, including:

[0011] The time-frequency plane of the received signal is rotated by fractional Fourier transform. The type of interference signal is determined by the different projections of the interference signal in the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after Fourier transform, and then the center frequency and bandwidth of each sampling segment are determined.

[0012] Specifically, the step of rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain, and determining the sampling length by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment, includes:

[0013] Perform a fractional Fourier transform on the received signal of the optimal order of the transmitted signal. If the received signal is characterized by a single spike on a semi-circular envelope in the spectrum, then the type of interference signal is determined to be spectral dispersion interference.

[0014] The received signal is subjected to fractional-order transformations of different orders. Different orders of fractional-order transformations are designed to correspond to different integer multiple slopes. The possible integer multiple slopes are traversed. The slope information of the interference signal is obtained by using the fractional-order Fourier order with multiple peaks. The center frequency and bandwidth of the interference signal are consistent with the center frequency and bandwidth of the transmitted signal.

[0015] Specifically, the step of rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain, and determining the sampling length by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment, includes:

[0016] If the received signal is subjected to a fractional Fourier transform of the optimal order of the transmitted signal, and the signal exhibits multiple decreasing peaks in the spectrum, then the interference signal type is determined to be intermittent sampling cyclic forwarding interference.

[0017] The received signal is subjected to Fourier transform, and the number of cyclic forwardings is obtained by using the number of spectral peaks. The number of interruptions in the peak interval is obtained by using the number of cyclic forwardings.

[0018] Divide the duration of the transmitted signal by the number of interruptions in the peak interval to obtain the sampling and forwarding duration.

[0019] Based on the frequency and bandwidth information of the transmitted signal, and combined with the sampling and forwarding time length, the frequency and bandwidth information of the entire intermittent sampling cyclic forwarding interference are obtained.

[0020] Specifically, the step of rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain, and determining the sampling length by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment, includes:

[0021] Perform a Fourier transform on the received signal and obtain the number of samples or slices by the number of times the peak intervals appear in the spectrum;

[0022] The number of forwards after each sampling or slice is obtained by using the ratio of the bandwidth of the signal after removing the peak to the bandwidth of the peak interval.

[0023] The time domain length of a single sampling forwarding is obtained by dividing the entire time domain length by the sum of the number of samplings and the number of forwardings after each sampling; or, the time domain length of a single slice forwarding is obtained by dividing the entire time domain length by the sum of the number of slices and the number of forwardings after each slice.

[0024] Using the obtained time-domain length of a single sampling forwarding or the time-domain length of a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal using the kernel function, thereby rotating the time-frequency plane of the interference signal. If the interference energy projection is discontinuous in time and has only a single peak, then the interference signal type is determined to be intermittent sampling direct forwarding interference.

[0025] Based on the sampling and forwarding length information, the center frequency and bandwidth of the intermittent sampling direct forwarding interference at the forwarding time are equal to the center frequency and bandwidth of the transmitted signal at the sampling time.

[0026] Specifically, the step of rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain, and determining the sampling length by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment, includes:

[0027] Perform a Fourier transform on the received signal and obtain the number of samples or slices by the number of times the peak intervals appear in the spectrum;

[0028] The number of forwards after each sampling or slice is obtained by using the ratio of the bandwidth of the signal after removing the peak to the bandwidth of the peak interval.

[0029] The time domain length of a single sampling forwarding is obtained by dividing the entire time domain length by the sum of the number of samplings and the number of forwardings after each sampling; or, the time domain length of a single slice forwarding is obtained by dividing the entire time domain length by the sum of the number of slices and the number of forwardings after each slice.

[0030] Using the obtained time-domain length of a single sampling forwarding or the time-domain length of a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal using the kernel function, thereby rotating the time-frequency plane of the interference signal. If the interference energy projection is discontinuous in time and has multiple peaks, the interference signal type is determined to be intermittent sampling and repetitive forwarding interference.

[0031] Based on the sampling and forwarding length information, the center frequency and bandwidth of the intermittent sampling and repeated forwarding interference at the forwarding time are equal to the center frequency and bandwidth of the transmitted signal at the sampling time.

[0032] Specifically, the step of rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain, and determining the sampling length by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment, includes:

[0033] Perform a Fourier transform on the received signal and obtain the number of samples or slices by the number of times the peak intervals appear in the spectrum;

[0034] The number of forwards after each sampling or slice is obtained by using the ratio of the bandwidth of the signal after removing the peak to the bandwidth of the peak interval.

[0035] The time domain length of a single sampling forwarding is obtained by dividing the entire time domain length by the sum of the number of samplings and the number of forwardings after each sampling; or, the time domain length of a single slice forwarding is obtained by dividing the entire time domain length by the sum of the number of slices and the number of forwardings after each slice.

[0036] Using the obtained time-domain length of a single sampling forwarding or the time-domain length of a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal using the kernel function, thereby rotating the time-frequency plane of the interference signal. If the interference energy projection is continuous in time and has multiple peaks, the interference signal type is determined to be slice reconstruction interference.

[0037] Based on the length information of the slice forwarding, the center frequency and bandwidth of the slice reconstruction interference at both the forwarding and slicing times are equal to the center frequency and bandwidth of the transmitted signal at the time of slicing.

[0038] This invention also provides a system for determining the type and parameters of interference signals based on microwave photonics technology, comprising: a light source module, an optical power divider, a first electro-optic modulator, a second electro-optic modulator, an optical signal generator, an optical mixer, a photodetector, and a spectrum analyzer; the optical output terminal of the light source module is optically connected to the optical input terminal of the optical power divider, the first optical output terminal of the optical power divider is optically connected to the first optical input terminal of the first electro-optic modulator, and the second optical output terminal of the optical power divider is optically connected to the first optical input terminal of the second electro-optic modulator; the second optical input terminal of the first electro-optic modulator is used to receive radar feedback. The optical signal; the second optical input terminal of the second electro-optic modulator is connected to the optical output terminal of the optical signal generator; the optical output terminals of the first and second electro-optic modulators are respectively connected to the optical input terminal of the optical mixer, the optical output terminal of the optical mixer is connected to the optical input terminal of the photodetector, and the optical output terminal of the photodetector is connected to the optical input terminal of the spectrum analyzer; by adjusting the starting frequency and frequency modulation slope of the reference signal to correspond to different transformation kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are linear canonical transformation results.

[0039] Specifically, it also includes: a low-noise amplifier; the electrical output terminal of the photodetector is communicatively connected to the electrical input terminal of the low-noise amplifier, and the electrical output terminal of the low-noise amplifier is communicatively connected to the electrical input terminal of the spectrum analyzer.

[0040] One or more technical solutions provided in this invention have at least the following technical effects or advantages:

[0041] By utilizing microwave photonics technology to modulate broadband interference signals into the optical domain, and dynamically matching the LCT transform kernel function by adjusting the reference signal parameters, LCT operations are directly performed in the analog domain, allowing the interference signal to be focused in the optimal LCT domain. Based on the time-frequency characteristics after focusing, real-time type determination and parameter estimation of the interference signal are achieved, completely avoiding the digital domain iterative operations of existing electronic methods, and reducing computational complexity from... Down to The parameter estimation delay reaches the microsecond level and there is no broadband throughput bottleneck; the parameter tuning delay depends only on the adjustment rate of the reference signal, which can adapt to the type identification and parameter estimation requirements of various types of broadband interference signals such as linear frequency modulation, frequency hopping, slice combination, and intermittent sampling and forwarding, and significantly enhances the anti-environment interference capability and stability. Attached Figure Description

[0042] Figure 1 A schematic diagram of the method for determining interference signal type and parameters based on microwave photonics technology provided in an embodiment of the present invention;

[0043] Figure 2 The above are the measured results of interference signal type identification and parameter determination in the embodiments of the present invention;

[0044] Figure 3 A schematic diagram of a system for determining interference signal type and parameters based on microwave photonics technology provided in an embodiment of the present invention;

[0045] Figure 4 The effect of the equivalent linear canonical transformation corresponding to the interference signal type and parameter determination system based on microwave photonics technology provided in the embodiments of the present invention;

[0046] Figure 5 The results of Fourier transform and chirped convolution achieved using microwave photonic LCT in this embodiment of the invention;

[0047] Figure 6 This is the result of fractional Fourier transform achieved using microwave photonic LCT in an embodiment of the present invention. Detailed Implementation

[0048] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0049] like Figure 1 As shown, the method for determining the type and parameters of interference signals based on microwave photonics technology provided in this embodiment of the invention includes:

[0050] The first electro-optic modulator receives the first optical carrier and the radar echo signal carrying interference, respectively, so as to realize the modulation of the first optical carrier by the radar echo signal, and input the modulated optical signal into the optical mixer.

[0051] The second optical carrier and the reference signal are received by the second electro-optic modulator, respectively, so that the reference signal modulates the second optical carrier, and the modulated optical signal is input into the optical mixer.

[0052] The two modulated optical signals are orthogonally mixed by an optical mixer, and the orthogonally mixed optical signal is output to a balanced photodetector to realize the conjugate multiplication of the radar echo signal and the reference signal.

[0053] The electrical signal output from the balanced photodetector is sent to the spectrum analyzer, which outputs the type and parameters of the interference signal. Specifically, by adjusting the starting frequency and frequency modulation slope of the reference signal to correspond to different transformation kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are the results of linear canonical transformation.

[0054] More specifically, by adjusting the starting frequency and modulation slope of the reference signal to correspond to different transform kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are the results of a linear canonical transform, including:

[0055] The time-frequency plane of the received signal is rotated by fractional Fourier transform. The type of interference signal is determined by the different projections of the interference signal in the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after Fourier transform, and then the center frequency and bandwidth of each sampling segment are determined.

[0056] Furthermore, such as Figure 2 As shown, the time-frequency plane of the received signal is rotated using a fractional Fourier transform. The type of interference signal is determined by utilizing the different projections of the interference signal onto the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the interference signal's projection onto the frequency domain after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment, including:

[0057] If the received signal is subjected to a fractional Fourier transform of the optimal order of the transmitted signal, and the signal exhibits a single spike on a semi-circular envelope in the spectrum, then the interference signal type is determined to be spectral dispersion interference.

[0058] Since the interference slope is usually an integer multiple of the transmitted signal slope, different orders of fractional-order transforms are performed on the received signal. A signal with a certain slope will only be focused under the fractional-order Fourier transform corresponding to its optimal order. Therefore, fractional-order transforms of different orders are designed to correspond to different integer multiple slopes. By traversing the possible integer multiple slopes, the slope information of the interference signal is obtained by using the fractional-order Fourier transforms that have multiple peaks. The center frequency and bandwidth of the interference signal are consistent with the center frequency and bandwidth of the transmitted signal.

[0059] or,

[0060] If the received signal is subjected to a fractional Fourier transform of the optimal order of the transmitted signal, and the spectrum shows multiple decreasing peaks, then the interference signal type is determined to be intermittent sampling cyclic forwarding interference.

[0061] The received signal undergoes a Fourier transform. After each sampling, the signal is forwarded multiple times. During forwarding, the energy is greater than the normal echo energy, resulting in a spectral spike each time. Therefore, the number of spectral spikes can be used to determine the number of cyclic forwardings. The jammer performs cyclic forwarding after each sampling, without transmitting a signal during the sampling process. Each sampling results in a discontinuity in the peak interval. The number of discontinuities in the peak interval can be obtained by counting the number of cyclic forwardings.

[0062] The sampling and forwarding length of the jammer is obtained by using the number of interruptions in the peak interval. Specifically, the jammer does not transmit a signal during each sampling, and the power of the echo will decrease, which is manifested as an interruption in the peak interval. The number of interruptions in the peak interval corresponds to the number of sampling and forwarding. The number of intermittent sampling and repeated forwarding interference sampling is the same as the number of forwarding. Therefore, the sampling and forwarding time length is obtained by dividing the time width of the transmitted signal by the number of interruptions in the peak interval.

[0063] Taking advantage of the fact that the jammer is a sampled and forwarded target signal, the jammer's transmitted signal is the radar transmitted signal at the time of the previous sampling interval. Since the transmitted signal is known, the frequency and bandwidth information of the entire intermittent sampling and forwarding jamming can be obtained by combining the frequency and bandwidth information of the transmitted signal with the sampling and forwarding time length.

[0064] or,

[0065] Upon receiving the interference signal, a fractional Fourier transform of the optimal order corresponding to the transmitted signal is performed. If the spectrum does not exhibit the aforementioned spectral dispersion interference or intermittent sampling cyclic forwarding interference, a Fourier transform is performed on the received signal. The number of samplings or slices is obtained by using the number of occurrences of peak intervals in the spectrum, i.e., how many times the jammer sampled or sliced ​​the signal. Specifically, the number of samplings corresponds to the number of times the interference is intermittent sampling, and the number of slices corresponds to the number of times the interference is reconstructed.

[0066] After sampling a segment of transmitted signal, the jammer forwards it multiple times. The unsampled moments are used to forward the signal from the sampling moment. The forwarding moments will show the peak value of the spectrum from the sampling moment. Therefore, the bandwidth of the signal after removing the peak value is an integer multiple of the bandwidth of the peak interval. The number of forwards after each sampling or each slice is obtained by using the ratio of the bandwidth after removing the peak value to the bandwidth of the peak interval. That is, how many times it is forwarded after one sampling or how many times it is forwarded after one slice.

[0067] The time domain length of a single sample-forward operation can be obtained by dividing the entire time domain length by the number of samples and the sum of the number of forwards after each sample; or, the time domain length of a single slice-forward operation can be obtained by dividing the entire time domain length by the number of slices and the sum of the number of forwards after each slice. Specifically, the jammer operates by sampling (slicing) a segment of signal and then forwarding that segment of signal one or more times. The duration of each forward is equal to the duration of the sampling (slicing). The sampling (slicing) and forwarding processes constitute the entire time domain interval of the jamming signal. The length of the entire time domain interval of the jamming signal is the same as that of the transmitted signal. Therefore, after obtaining the number of samples (slices) and forwards, the duration of either the sampling (slicing) or a single forward can be obtained by dividing the entire time domain length by the sum of the number of samples (slices) and forwards.

[0068] Using the time-domain length of a single sample forwarding or a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function generated by any signal generator; the kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal to rotate the time-frequency plane of the interference signal. If the interference energy projection is discontinuous in time and has only a single peak, the interference signal type is determined to be intermittent sampling direct forwarding interference.

[0069] After obtaining the length of the interference signal and the number of sampling and forwarding times, since the interference signal is obtained by sampling and forwarding the transmitted signal, the center frequency and bandwidth of the transmitted signal are known. Combining the sampling and forwarding length information, the center frequency and bandwidth of the interference at the time of forwarding during intermittent sampling are equal to the center frequency and bandwidth of the transmitted signal at the time of sampling.

[0070] or,

[0071] Upon receiving the interference signal, a fractional Fourier transform of the optimal order corresponding to the transmitted signal is performed. If the spectrum does not exhibit the aforementioned spectral dispersion interference or intermittent sampling cyclic forwarding interference, a Fourier transform is performed on the received signal. The number of samplings or slices is obtained by using the number of occurrences of peak intervals in the spectrum, i.e., how many times the jammer sampled or sliced ​​the signal. Specifically, the number of samplings corresponds to the number of times the interference is intermittent sampling, and the number of slices corresponds to the number of times the interference is reconstructed.

[0072] After sampling a segment of transmitted signal, the jammer forwards it multiple times. The unsampled moments are used to forward the signal from the sampling moment. The forwarding moments will show the peak value of the spectrum from the sampling moment. Therefore, the bandwidth of the signal after removing the peak value is an integer multiple of the bandwidth of the peak interval. The number of forwards after each sampling or each slice is obtained by using the ratio of the bandwidth after removing the peak value to the bandwidth of the peak interval. That is, how many times it is forwarded after one sampling or how many times it is forwarded after one slice.

[0073] The time domain length of a single sample-forward operation can be obtained by dividing the entire time domain length by the number of samples and the sum of the number of forwards after each sample; or, the time domain length of a single slice-forward operation can be obtained by dividing the entire time domain length by the number of slices and the sum of the number of forwards after each slice. Specifically, the jammer operates by sampling (slicing) a segment of signal and then forwarding that segment of signal one or more times. The duration of each forward is equal to the duration of the sampling (slicing). The sampling (slicing) and forwarding processes constitute the entire time domain interval of the jamming signal. The length of the entire time domain interval of the jamming signal is the same as that of the transmitted signal. Therefore, after obtaining the number of samples (slices) and forwards, the duration of either the sampling (slicing) or a single forward can be obtained by dividing the entire time domain length by the sum of the number of samples (slices) and forwards.

[0074] Using the time-domain length of a single sample forwarding or a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function generated by any signal generator is used. The kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal to rotate the time-frequency plane of the interference signal. Due to its sampling and forwarding characteristics, the signal cannot be forwarded when it is sampled. Therefore, the interference can be eliminated when the above kernel function is used for transformation. Therefore, if the interference energy projection is discontinuous in time and has multiple peaks, the interference signal type is determined to be intermittent sampling and repetitive forwarding interference.

[0075] After obtaining the length of the interference signal and the number of sampling and forwarding times, since the interference signal is obtained by sampling and forwarding the transmitted signal, combined with the length information of sampling and forwarding, the center frequency and bandwidth of the intermittent sampling and repeated forwarding interference at the forwarding time are equal to the center frequency and bandwidth of the transmitted signal at the sampling time.

[0076] or,

[0077] Upon receiving the interference signal, a fractional Fourier transform of the optimal order corresponding to the transmitted signal is performed. If the spectrum does not exhibit the aforementioned spectral dispersion interference or intermittent sampling cyclic forwarding interference, a Fourier transform is performed on the received signal. The number of samplings or slices is obtained by using the number of occurrences of peak intervals in the spectrum, i.e., how many times the jammer sampled or sliced ​​the signal. Specifically, the number of samplings corresponds to the number of times the interference is intermittent sampling, and the number of slices corresponds to the number of times the interference is reconstructed.

[0078] After sampling a segment of transmitted signal, the jammer forwards it multiple times. The unsampled moments are used to forward the signal from the sampling moment. The forwarding moments will show the peak value of the spectrum from the sampling moment. Therefore, the bandwidth of the signal after removing the peak value is an integer multiple of the bandwidth of the peak interval. The number of forwards after each sampling or each slice is obtained by using the ratio of the bandwidth after removing the peak value to the bandwidth of the peak interval. That is, how many times it is forwarded after one sampling or how many times it is forwarded after one slice.

[0079] The time domain length of a single sample-forward operation can be obtained by dividing the entire time domain length by the number of samples and the sum of the number of forwards after each sample; or, the time domain length of a single slice-forward operation can be obtained by dividing the entire time domain length by the number of slices and the sum of the number of forwards after each slice. Specifically, the jammer operates by sampling (slicing) a segment of signal and then forwarding that segment of signal one or more times. The duration of each forward is equal to the duration of the sampling (slicing). The sampling (slicing) and forwarding processes constitute the entire time domain interval of the jamming signal. The length of the entire time domain interval of the jamming signal is the same as that of the transmitted signal. Therefore, after obtaining the number of samples (slices) and forwards, the duration of either the sampling (slicing) or a single forward can be obtained by dividing the entire time domain length by the sum of the number of samples (slices) and forwards.

[0080] Using the time-domain length of a single sample forwarding or a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function generated by any signal generator is used. The kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal to rotate the time-frequency plane of the interference signal. Here, unlike intermittent sampling and repetitive forwarding interference, although a time-discontinuous kernel function is used for transformation, the characteristics of slice reconstruction interference (the interference is forwarded in the next pulse repetition cycle after one slice sampling, so it is continuous in the time domain) determine the continuity of its energy in the time domain. Therefore, if the interference energy projection is continuous in time and has multiple peaks, the interference signal type is determined to be slice reconstruction interference.

[0081] After obtaining the length of the interference signal and the number of slice forwardings, since the interference signal is obtained by slicing and forwarding the transmitted signal, combined with the slice forwarding length information, the center frequency and bandwidth of the slice reconstructed interference at the forwarding time and the slicing time are equal to the center frequency and bandwidth of the transmitted signal at the time of slicing.

[0082] like Figure 3 As shown in the embodiment of the present invention, the interference signal type and parameter determination system based on microwave photonics technology includes: a light source module, an optical power divider, a first electro-optic modulator, a second electro-optic modulator, an optical signal generator, an optical mixer, a photodetector, and a spectrum analyzer; the optical output terminal of the light source module is optically connected to the optical input terminal of the optical power divider, the first optical output terminal of the optical power divider is optically connected to the first optical input terminal of the first electro-optic modulator, and the second optical output terminal of the optical power divider is optically connected to the first optical input terminal of the second electro-optic modulator; the second optical input terminal of the first electro-optic modulator is used for... The system receives radar echo signals; the second optical input of the second electro-optic modulator is connected to the optical output of the optical signal generator; the optical outputs of the first and second electro-optic modulators are connected to the optical input of the optical mixer, the optical output of the optical mixer is connected to the optical input of the photodetector, and the optical output of the photodetector is connected to the optical input of the spectrum analyzer; by adjusting the starting frequency and modulation slope of the reference signal to correspond to different transformation kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are the results of linear canonical transformation.

[0083] Further explanation of the interference signal type and parameter determination system based on microwave photonics technology provided in this embodiment of the invention includes: a low-noise amplifier; the electrical output terminal of the photodetector is communicatively connected to the electrical input terminal of the low-noise amplifier, and the electrical output terminal of the low-noise amplifier is communicatively connected to the electrical input terminal of the spectrum analyzer.

[0084] The working principle of the interference signal type and parameter determination system based on microwave photonics technology provided in this embodiment of the invention will be explained in detail below:

[0085] The optical output terminal of the light source module (single-frequency continuous laser, center wavelength 1550nm, power 16dBm) is connected to the input terminal of a 50:50 optical power divider, splitting a single optical carrier into two equal-power optical signals. The first output terminal of the 50:50 optical power divider is connected to the optical input terminal of a first electro-optic modulator (bandwidth 20GHz, operating in quadrature bias mode). The RF input terminal of the first electro-optic modulator is connected to a low-noise amplifier (frequency range 0.5-20 GHz). The radar echo signal amplified by GHz (gain 25dB) after interference; the second output of the 50:50 optical power divider is connected to the optical input of the second electro-optic modulator (bandwidth 20GHz, operating in quadrature bias state), and the RF input of the second electro-optic modulator is connected to the output of the optical signal generator (AWG, arbitrary signal generator); the optical outputs of the first and second electro-optic modulators are connected to the input of the optical mixer to realize quadrature mixing of the two modulated optical signals, ensuring that the balanced photodetector can accurately extract the "conjugate multiplication component of the test signal and the reference signal" and suppress quadrature component interference; the optical mixer realizes... After optical mixing, the output of the optical mixer is connected to the optical input of a balanced photodetector (BPD, bandwidth 40 GHz) to achieve conjugate multiplication of the radar echo signal and the reference signal. The electrical output of the balanced photodetector is connected to the input of a low-noise amplifier (frequency range 0.5-20 GHz, gain 25dB), and the output of the low-noise amplifier is connected to the signal input of a real-time spectrum analyzer (frequency range 0-40 GHz). The optical signal generator receives external control commands through a programmable interface (SPI) to achieve real-time adjustment of the reference signal's starting frequency and modulation slope, corresponding to different transform kernel functions. The output of the real-time spectrum analyzer is connected to a display terminal.

[0086] Specifically, such as Figure 4 As shown, the reference signal is equivalent to a kernel function that is multiplied by the conjugate of the radar echo signal. Different parameters of the reference signal (slope and frequency) correspond to different kernel functions. The optical mixer and the balanced photodetector are used to realize the conjugate multiplication of the reference signal and the radar echo signal, while the spectrum analyzer is used to directly display the result after its Fourier transform, that is, the result of the linear canonical transform.

[0087] Figure 5 (a) shows the Fourier transform result of the input signal, which is a linear frequency modulated signal with a center frequency of 13.4 GHz and a bandwidth of 1 GHz. According to theoretical analysis, the reference signal does not need to be input at this time, which is equivalent to no modulation signal in the lower branch, with only the optical carrier present. At this time, the Fourier transform result can be obtained directly from the spectrum analyzer. Figure 5(b) shows the result of its chirped convolution. The input radar echo signal is the same as above. When the reference signal is a linear frequency modulated signal with the same slope but a different center frequency, the result of its chirped convolution is the difference between the center frequencies of the two signals. When different single-frequency radar echo signals are input for chirped convolution, the output result is equivalent to a spectral shift of the reference chirped signal. The spectral shift amount is the difference between the radar echo signal and the reference chirped signal. Figure 5 As can be observed in (c), as the center frequency of the input radar echo signal gradually decreases, the spectral shift gradually increases. Utilizing the spectral shift characteristic, when the radar echo signal, after modulation, manifests as a set of optical frequency combs in the optical domain, a result similar to convolving the optical frequency comb set generated by modulating the reference signal and the radar echo signal in the frequency domain can be obtained. Figure 5 (d) shows the result of convolving an optical frequency comb with an input signal of 1 GHz and a linear frequency modulated signal with a center frequency of 8 GHz and a bandwidth of 500 MHz. Due to the nature of convolution, the broadband signal is transferred to each tooth of the optical frequency comb.

[0088] Figure 6 (a) illustrates how the Fourier transform of the input linear frequency modulated signal varies with the slope of the input reference signal, resulting in a constantly changing projection in the fractional Fourier domain. As the slope of the reference signal gradually increases, the bandwidth of the fractional Fourier transform of the output radar echo signal gradually decreases. This is because the projection of the signal in the fractional Fourier domain gradually decreases due to the rotation of the time-frequency plane. When the slope of the input reference signal is 1000 Hz / s, it corresponds to the optimal order of the fractional Fourier transform of the radar echo signal. At this point, the projection of the radar echo signal in the fractional Fourier domain is a single-frequency signal, and the signal energy is focused in the fractional Fourier domain. Then, as the slope of the input reference signal increases, the order of the fractional Fourier transform of the signal changes, and the signal energy is gradually dispersed. From... Figure 6 (b) In the time-frequency analysis results of the output results corresponding to the reference signals with different slopes, the rotation characteristics of the reference signal in the time-frequency space can be observed intuitively. Because the projection of the signal in the fractional Fourier domain is different due to the rotation characteristics, the corresponding output results are different.

[0089] To facilitate public understanding, the technical solution of this invention will be further described in detail below from a theoretical perspective.

[0090] This system achieves equivalent computation of the LCT kernel function and radar echo signal through optical domain modulation and mixing, and directly outputs the results by combining spectrum analysis. The specific process is as follows:

[0091] The laser outputs a continuous optical carrier wave, and its expression is:

[0092]

[0093] in, The peak amplitude of the optical carrier wave. optical carrier frequency The optical carrier is split into two equal-power optical signals by a 50:50 optical splitter. and ,satisfy .

[0094] radar echo signal The first electro-optic modulator is input to its RF port and operates at the quadrature modulation point (bias voltage is...). Through the electro-optic effect Loaded to optical carrier Output modulated optical signal:

[0095]

[0096] in, Given the inherent phase shift of the first electro-optic modulator, ignoring small-signal approximation errors, and after trigonometric function expansion (retaining the first-order sideband components and suppressing higher-order components through subsequent filtering), the core component is:

[0097]

[0098] Arbitrary signal generator outputs LFM signal Its expression is:

[0099]

[0100] in, The reference signal start frequency, This is the frequency modulation slope (a core adjustable parameter). This signal is input to the RF port of the second electro-optic modulator, and similarly outputs a modulated optical signal.

[0101]

[0102] in, This is the inherent phase shift of the second electro-optic modulator.

[0103] Two modulated optical signals and Input 50:50 optical power splitter beam combining, beam combining signal The light then enters the optical mixer. Through optical interference effects, the mixer output contains... The optical signal of the beat frequency component ( for (conjugate of), the optical carrier component and common-mode noise are suppressed by subsequent BPD, and the core beat frequency component is:

[0104]

[0105] Mixed optical signal The input is a balanced photodetector (BPD). The BPD converts optical power into photocurrent through the photoelectric effect, and uses common-mode rejection characteristics to cancel out optical carrier and environmental noise, outputting a current signal.

[0106]

[0107] in, For BPD photoelectric conversion efficiency, This represents the real part. The current signal output by the BPD is amplified by a low-noise amplifier (LNA) and converted into an electrical signal, which is then input to a real-time spectrum analyzer. The spectrum analyzer performs a Fast Fourier Transform (FFT) on it to obtain:

[0108]

[0109] Conjugate the reference signal Substituting, we get:

[0110]

[0111] The definition of linear canonical transform is:

[0112]

[0113] This represents "shaping" or "distorting" the signal, but does not change its essential time-frequency representation; while This refers to the "propagation" or "transformation" of a signal, which changes the time-frequency representation of the signal, producing new frequency components or positions. This is the most common and core case, encompassing the most basic linear regular transformation. This embodiment will only discuss this aspect. In the case of,

[0114]

[0115] Therefore, formula (10) can also be written as

[0116]

[0117] Where ABCD are integers, and D is the index. By comparing formula (9) with formula (10) and making the coefficients of the exponent terms equal, the mapping relationship between the reference signal parameters and the LCT parameter matrix is ​​derived:

[0118] FM slope Starting frequency Matrix parameters .

[0119] nature :

[0120]

[0121] Analogous to formula (13), when both the starting frequency and the frequency modulation slope are 0.

[0122]

[0123] At this point, formula (14) also becomes a form of Fourier transform of the signal, which can beat the signal modulated on the optical carrier with the optical carrier frequency, and the output signal can be directly connected to the spectrum analyzer, so that its frequency domain result can be obtained directly.

[0124] nature :

[0125]

[0126] When a linear frequency modulated signal with a slope equal to negative 1 / 2a is input,

[0127]

[0128] Its Fourier transform form is

[0129]

[0130] in

[0131]

[0132] Therefore, we can obtain

[0133]

[0134] Formula (19) is transformed into the form of convolution of the signal and the chirped signal, with the following properties. Proof obtained.

[0135] nature :

[0136]

[0137]

[0138] When the input signal is an arbitrary chirp signal

[0139]

[0140] Substitute into the following formula

[0141]

[0142] Its integral part is

[0143]

[0144] In this system, the input linear frequency modulation signal

[0145]

[0146] After obtaining the beat frequency

[0147]

[0148] Its Fourier transform is

[0149]

[0150] This integral is related to formula (24) The forms are the same, only the variables are different. Specifically, when hour:

[0151]

[0152] therefore

[0153]

[0154] For the integral part, under the condition that When the unique peak point of the above and below equations is the same, At that time, the peak point was

[0155]

[0156] That is, the target echo is focused in the u-domain as a single-peak sinc function, and the peak position uniquely corresponds to the modulation frequency k. This phase is only related to the LCT domain variable u and is independent of time t. It only changes the overall phase distribution of the LCT output and does not affect the amplitude spectrum. If the amplitude characteristics of the signal are of interest (such as peak detection and interference suppression), it can be directly ignored.

[0157] In other words, through regulation and This allows for the arbitrary fulfillment of the input signal's requirements. The LCT transformation of the spectrum analyzer outputs the spectrum. Amplitude calibration (coefficient) After that, the result is the standard LCT result, which is directly displayed on the terminal.

[0158] In summary, this invention discloses a method and system for determining the type and estimating the parameters of broadband interference signals based on microwave photonics technology. Through a core architecture of "optical domain signal modulation - optical mixing LCT equivalent - time-frequency focusing - parameter extraction," it achieves rapid and high-precision determination of broadband interference signal types and parameters. It utilizes optical mixing and balanced detection to perform analog domain kernel function calculations, and then directly outputs the LCT results through spectral analysis. This invention eliminates the need for complex iterative calculations in the digital domain. By adjusting the reference signal parameters, different LCT parameter matrices can be flexibly matched to achieve various special forms and generalized LCT transformations, such as Fourier transform, chirped convolution, and fractional Fourier transform. It balances low complexity, high real-time performance, and parameter adjustability, thereby enabling the classification and parameter estimation of interference signals for subsequent interference suppression.

[0159] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0160] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0161] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0162] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0163] Any aspects of this invention not described in detail in the embodiments are well-known techniques to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this invention and not to limit it. Although this invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this invention without departing from the spirit and scope of this invention, and all such modifications and substitutions should be covered within the scope of the claims of this invention.

Claims

1. A method for determining the type and parameters of interference signals based on microwave photonics technology, characterized in that, include: The first electro-optic modulator receives the first optical carrier and the radar echo signal carrying interference, respectively, so as to realize the modulation of the first optical carrier by the radar echo signal, and input the modulated optical signal into the optical mixer. The second electro-optic modulator receives the second optical carrier and the reference signal respectively, realizes the modulation of the second optical carrier by the reference signal, and inputs the modulated optical signal into the optical mixer; The optical mixer enables orthogonal mixing of two modulated optical signals, and the orthogonally mixed optical signal is output to a balanced photodetector to achieve conjugate multiplication of the radar echo signal and the reference signal. The balanced photodetector outputs an electrical signal to a spectrum analyzer, which outputs the type and parameters of the interference signal. Specifically, by adjusting the starting frequency and modulation slope of the reference signal to correspond to different transformation kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are the result of a linear canonical transformation.

2. The method for determining the type and parameters of interference signals based on microwave photonics technology as described in claim 1, characterized in that, By adjusting the starting frequency and frequency modulation slope of the reference signal to correspond to different transform kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are linear canonical transform results, including: The time-frequency plane of the received signal is rotated by fractional Fourier transform. The type of interference signal is determined by the different projections of the interference signal in the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projection of the interference signal after Fourier transform, and then the center frequency and bandwidth of each sampling segment are determined.

3. The method for determining the type and parameters of interference signals based on microwave photonics technology as described in claim 2, characterized in that, The process involves rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projections of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment. This includes: Perform a fractional Fourier transform on the received signal of the optimal order of the transmitted signal. If the received signal is characterized by a single spike on a semi-circular envelope in the spectrum, then the type of interference signal is determined to be spectral dispersion interference. The received signal is subjected to fractional-order transformations of different orders. Different orders of fractional-order transformations are designed to correspond to different integer multiple slopes. The possible integer multiple slopes are traversed. The slope information of the interference signal is obtained by using the fractional-order Fourier order with multiple peaks. The center frequency and bandwidth of the interference signal are consistent with the center frequency and bandwidth of the transmitted signal.

4. The method for determining the type and parameters of interference signals based on microwave photonics technology as described in claim 2, characterized in that, The process involves rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projections of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment. This includes: If the received signal is subjected to a fractional Fourier transform of the optimal order of the transmitted signal, and the signal exhibits multiple decreasing peaks in the spectrum, then the interference signal type is determined to be intermittent sampling cyclic forwarding interference. The received signal is subjected to Fourier transform, and the number of cyclic forwardings is obtained by using the number of spectral peaks. The number of interruptions in the peak interval is obtained by using the number of cyclic forwardings. Divide the duration of the transmitted signal by the number of interruptions in the peak interval to obtain the sampling and forwarding duration. Based on the frequency and bandwidth information of the transmitted signal, and combined with the sampling and forwarding time length, the frequency and bandwidth information of the entire intermittent sampling cyclic forwarding interference are obtained.

5. The method for determining the type and parameters of interference signals based on microwave photonics technology as described in claim 2, characterized in that, The process involves rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projections of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment. This includes: Perform a Fourier transform on the received signal and obtain the number of samples or slices by the number of times the peak intervals appear in the spectrum; The number of forwards after each sampling or slice is obtained by using the ratio of the bandwidth of the signal after removing the peak to the bandwidth of the peak interval. The time domain length of a single sampling forwarding is obtained by dividing the entire time domain length by the sum of the number of samplings and the number of forwardings after each sampling; or, the time domain length of a single slice forwarding is obtained by dividing the entire time domain length by the sum of the number of slices and the number of forwardings after each slice. Using the obtained time-domain length of a single sampling forwarding or the time-domain length of a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal using the kernel function, thereby rotating the time-frequency plane of the interference signal. If the interference energy projection is discontinuous in time and has only a single peak, then the interference signal type is determined to be intermittent sampling direct forwarding interference. Based on the sampling and forwarding length information, the center frequency and bandwidth of the intermittent sampling direct forwarding interference at the forwarding time are equal to the center frequency and bandwidth of the transmitted signal at the sampling time.

6. The method for determining the type and parameters of interference signals based on microwave photonics technology as described in claim 2, characterized in that, The process involves rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projections of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment. This includes: Perform a Fourier transform on the received signal and obtain the number of samples or slices by the number of times the peak intervals appear in the spectrum; The number of forwards after each sampling or slice is obtained by using the ratio of the bandwidth of the signal after removing the peak to the bandwidth of the peak interval. The time domain length of a single sampling forwarding is obtained by dividing the entire time domain length by the sum of the number of samplings and the number of forwardings after each sampling; or, the time domain length of a single slice forwarding is obtained by dividing the entire time domain length by the sum of the number of slices and the number of forwardings after each slice. Using the obtained time-domain length of a single sampling forwarding or the time-domain length of a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal using the kernel function, thereby rotating the time-frequency plane of the interference signal. If the interference energy projection is discontinuous in time and has multiple peaks, the interference signal type is determined to be intermittent sampling and repetitive forwarding interference. Based on the sampling and forwarding length information, the center frequency and bandwidth of the intermittent sampling and repeated forwarding interference at the forwarding time are equal to the center frequency and bandwidth of the transmitted signal at the sampling time.

7. The method for determining the type and parameters of interference signals based on microwave photonics technology as described in claim 2, characterized in that, The process involves rotating the time-frequency plane of the received signal using a fractional Fourier transform, and determining the type of interference signal by utilizing the different projections of the interference signal into the fractional domain. The sampling length is determined by the number of discontinuous frequency points and the bandwidth of the frequency point projections of the interference signal after the Fourier transform, thereby determining the center frequency and bandwidth of each sampling segment. This includes: Perform a Fourier transform on the received signal and obtain the number of samples or slices by the number of times the peak intervals appear in the spectrum; The number of forwards after each sampling or slice is obtained by using the ratio of the bandwidth of the signal after removing the peak to the bandwidth of the peak interval. The time domain length of a single sampling forwarding is obtained by dividing the entire time domain length by the sum of the number of samplings and the number of forwardings after each sampling; or, the time domain length of a single slice forwarding is obtained by dividing the entire time domain length by the sum of the number of slices and the number of forwardings after each slice. Using the obtained time-domain length of a single sampling forwarding or the time-domain length of a single slice forwarding as a priori signal, a time-discontinuous fractional Fourier transform kernel function is designed to avoid the interference energy range. The kernel function has the following form: ;in, For the time-domain energy range where interference does not exist, The center frequency of the transmitted signal. The slope of the transmitted signal. The amplitude of the kernel function is used to perform a photon-assisted linear canonical transformation on the interference signal using the kernel function, thereby rotating the time-frequency plane of the interference signal. If the interference energy projection is continuous in time and has multiple peaks, the interference signal type is determined to be slice reconstruction interference. Based on the length information of the slice forwarding, the center frequency and bandwidth of the slice reconstruction interference at both the forwarding and slicing times are equal to the center frequency and bandwidth of the transmitted signal at the time of slicing.

8. A system for determining the type and parameters of interference signals based on microwave photonics technology, characterized in that, include: The system comprises a light source module, an optical power divider, a first electro-optic modulator, a second electro-optic modulator, an optical signal generator, an optical mixer, a photodetector, and a spectrum analyzer. The optical output terminal of the light source module is connected to the optical input terminal of the optical power divider. The first optical output terminal of the optical power divider is connected to the first optical input terminal of the first electro-optic modulator, and the second optical output terminal of the optical power divider is connected to the first optical input terminal of the second electro-optic modulator. The second optical input terminal of the first electro-optic modulator is used to receive radar echo signals. The second optical input terminal of the second electro-optic modulator is connected to the optical output terminal of the optical signal generator. The optical output terminals of the first and second electro-optic modulators are respectively connected to the optical input terminal of the optical mixer. The optical output terminal of the optical mixer is connected to the optical input terminal of the photodetector, and the optical output terminal of the photodetector is connected to the optical input terminal of the spectrum analyzer. By adjusting the starting frequency and modulation slope of the reference signal to correspond to different transformation kernel functions, the type and parameters of the interference signal output by the spectrum analyzer are linear canonical transformation results.

9. The interference signal type and parameter determination system based on microwave photonics technology as described in claim 8, characterized in that, Also includes: Low-noise amplifier; The electrical output terminal of the photodetector is communicatively connected to the electrical input terminal of the low-noise amplifier, and the electrical output terminal of the low-noise amplifier is communicatively connected to the electrical input terminal of the spectrum analyzer.

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