Radar interference and safety communication integrated system based on microwave photons

Abstract

The invention discloses a radar interference and safety communication integrated system based on microwave photons. The radar interference and safety communication integrated system comprises an arbitrary waveform generator module, an integrated signal generation unit and a signal transmission unit, wherein the arbitrary waveform generator module is used for generating an OFDM (Orthogonal Frequency Division Multiplexing) signal and an LFM (Linear Frequency Modulation) signal, integrating the OFDM signal and the LFM signal into an FDM (Frequency Division Multiplexing) signal, and converting the FDM signal into an analog signal; the integrated signal generation unit is used for generating continuous optical carriers and modulating analog signals to the optical carriers to form optical coupling signals; an optical coupling signal has radar interference and safe communication characteristics; and the signal transmission unit is used for converting the optical coupling signal into an electric signal and processing and transmitting the electric signal. According to the technical scheme, active interference to enemy radars and encryption to own wireless communication signals can be simultaneously realized, and the device has the advantages of wide working frequency band, flexibility, adjustability, small influence of electromagnetic interference, low loss and the like, and overcomes the limitation of traditional electronics.

Description

Technical Field

[0001] The present invention relates to the field of optical communications, and in particular to an integrated system of radar jamming and safety communications based on microwave photons. Background Art

[0002] Electronic countermeasures is a very important field in modern warfare. It is based on one's own communications to protect one's own system from enemy interference and attack, and at the same time provides technical solutions for the destruction or interference of enemy systems. Among them, in order to destroy or interfere with the enemy system, it is necessary to implement radar jamming to emit interference signals to confuse the enemy radar; in order to ensure one's own secure communications and prevent the transmission information from being leaked or illegally intercepted, it is necessary to implement communication encryption. Therefore, radar jamming and signal encryption are two indispensable components in the field of electronic countermeasures; in common solutions, radar jamming and signal encryption require their own independent spectrum implementation.

[0003] With the rapid development of the wireless communication industry, spectrum congestion has become increasingly prominent. Therefore, a communication and perception integrated solution is needed to break the situation where radar interference and secure communication develop independently. In the traditional electromagnetic and electronic fields, when implementing the perception integrated solution, there are often limitations such as narrow working bandwidth, large electromagnetic interference, and high cost. Therefore, a technical solution is needed that can realize radar interference and secure communication on the same spectrum at the same time, and overcome the limitations of traditional solutions due to electromagnetic interference and working bandwidth. Summary of the invention

[0004] To achieve the above-mentioned purpose, the present application provides an integrated system of radar jamming and secure communication based on microwave photons, comprising: an arbitrary waveform generator module, an integrated signal generating unit and a signal transmission unit;

[0005] The arbitrary waveform generator module (103) is used to generate an OFDM signal and an LFM signal, integrate the OFDM signal and the LFM signal into an FDM signal, and then convert the FDM signal into an analog signal;

[0006] The integrated signal generation unit is used to generate a continuous optical carrier, modulate the analog signal onto the optical carrier, and form an optically coupled signal; the optically coupled signal has radar interference and safety communication characteristics;

[0007] The signal transmission unit is used to convert the optical coupling signal into an electrical signal, and process and transmit the electrical signal.

[0008] Wherein, before the arbitrary waveform generator module integrates the OFDM signal and the LFM signal into the FDM signal, it obtains the encrypted OFDM signal, and the encrypted OFDM signal is obtained by performing OFDM signal modulation on the encrypted QAM information.

[0009] A multi-volume Jerk chaotic system is used to encrypt the I and Q branches of the QAM signal to generate an encrypted QAM signal.

[0010] The encrypted QAM information is encrypted by a multi-volume Jerk chaotic system, including:

[0011] A set of chaotic sequences {x, y, z} is generated by using a multi-volume Jerk chaotic system; the initial values ​​{x0, y0, z0} are used as a shareable key for generating three chaotic sequences {x, y, z}; the original pseudo-random bit sequence is first subjected to a chaotic XOR operation with the chaotic sequence {z}; and QAM mapping is performed after the chaotic XOR operation;

[0012] The I and Q branches of the QAM signal are encrypted using the chaotic sequences {x} and {y}, which can be expressed as:

[0013] S′=(real[S]+bx)+j(imag[S]+by), where S′ represents the encrypted QAM signal, S represents the original QAM signal, and b represents the multiplication factor;

[0014] Among them, the chaotic system is realized by a set of ordinary differential equations, which can be expressed as:

[0015]

[0016] Further, the integrated signal generating unit includes: a first optical coupling module, an IQ modulation module, an erbium-doped fiber amplifier module, an optical phase modulation subunit and a second optical coupling module;

[0017] The first optical coupling module divides the continuous optical carrier into two paths, namely the IQ modulation module (104) and the optical phase modulation subunit;

[0018] The IQ modulation module modulates the analog signal onto the optical carrier to form an optical signal;

[0019] The erbium-doped fiber amplifier module is used to amplify the optical signal to compensate for the insertion loss of the modulator;

[0020] The optical phase modulation subunit is driven by two identical sawtooth wave signals to perform optical phase modulation on the optical carrier;

[0021] The second optical coupling module is used to couple the optical signals output by the IQ modulation module and the optical phase modulation subunit.

[0022] The optical phase modulation subunit consists of a dual parallel dual-drive Mach-Zehnder modulation module and a waveform generator module;

[0023] The waveform generator module is used to generate two identical sawtooth waves. The dual parallel dual drive Mach-Zehnder modulation module is driven by two identical sawtooth wave signals generated by the waveform generator module, biasing the DC at the maximum transmission point to achieve Serrodyn of the continuous optical carrier. e modulation.

[0024] When the waveform falling time of the sawtooth signal wave is less than 1% of the signal period, the dual parallel dual drive Mach-Zehnder modulation module is used for the optical carrier Serrodyn e The spurious signal suppression ratio of the modulation is greater than 40dB.

[0025] Further, the signal transmission unit includes a photoelectric detection module and a Ka-band horn antenna module;

[0026] The photoelectric detection module is used to convert the optical coupling signal into an electrical signal;

[0027] The Ka-band horn antenna module is used to filter out the part of the electrical signal outside the Ka-band and transmit it to the free space for transmission. According to the present invention, active interference to the enemy radar and encryption of the own wireless communication signal can be achieved at the same time, and it has the advantages of wide working frequency band, flexible adjustment, little influence by electromagnetic interference and low loss, and overcomes the limitations of traditional electronics, and further solves the problem of spectrum congestion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is a schematic diagram of the structure of a microwave photon-based radar jamming and security communication integrated system according to an embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of an OFDM signal encryption process provided by an embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of a spectrum output by an IQ modulation module provided in an optical simulation experiment according to an embodiment of the present invention;

[0031] Figure 4 is a schematic diagram of a spectrum output by a dual-parallel dual-drive Mach-Zehnder modulation module in an optical simulation experiment according to an embodiment of the present invention;

[0032] Figure 5 is a schematic diagram of a spectrum output by a second optical coupling module provided in an optical simulation experiment according to an embodiment of the present invention;

[0033] Figure 6 is a schematic diagram of an electrical spectrum output by a photoelectric detection module provided in an optical simulation experiment according to an embodiment of the present invention;

[0034] Figure numerals: 101-light emitting diode module; 102-optical coupling module OC1; 103-arbitrary waveform generator module; 104-IQ modulation module; 105-erbium-doped fiber amplifier module; 106-dual parallel dual-drive Mach-Zehnder modulation module; 107-waveform generator module; 108--optical coupling module 0C2; 109-photoelectric detection module; 110: horn antenna module. DETAILED DESCRIPTION

[0035] The specific implementation of the present invention is described in detail below with reference to the accompanying drawings.

[0036] The structure of the integrated system of radar jamming and secure communication based on microwave photons proposed by the present invention is as follows: Figure 1 As shown, it is composed of an arbitrary waveform generator module, an integrated signal generating unit and a signal transmission unit.

[0037] Arbitrary waveform generator module is used to generate OFDM signal E s and radar echo LFM signal E r , and integrated into an FDM signal. Among them, the OFDM signal E s The chaotic system has been encrypted to ensure secure communication.

[0038] Specifically, the encrypted OFDM signal is obtained by performing OFDM signal modulation on the encrypted QAM information.

[0039] In the present invention, a multi-volume Jerk chaotic system is firstly used to encrypt the I and Q branches of the QAM signal to generate an encrypted QAM signal; Figure 2 As shown, the encrypted QAM information is realized by a multi-volume Jerk chaotic system encryption method: a set of chaotic sequences {x, y, z} is generated by a multi-volume Jerk chaotic system, and the initial values ​​{x0, y0, z0} are used as a shareable key to generate three chaotic sequences {x, y, z}; the original pseudo-random bit sequence is first subjected to a chaotic XOR operation with the chaotic sequence {z}; QAM mapping is performed after the chaotic XOR operation;

[0040] Subsequently, the chaotic sequences {x} and {y} are used to encrypt the I and Q branches of the QAM signal, which is expressed as: S′=(real[S]+bx)+j(imag[S]+by), where S′ represents the encrypted QAM signal, S represents the original QAM signal, and b represents the multiplication factor.

[0041] Among them, the chaotic system is realized by a set of ordinary differential equations, which can be expressed as:

[0042]

[0043] Specifically, the OFDM signal Es and radar echo LFM signal E r They can be expressed as:

[0044]

[0045]

[0046] Where S BB represents the baseband chaotic encrypted OFDM signal, f RF Represents the OFDM signal E s The RF frequency, V represents the radar echo LFM signal E r The amplitude of f0 represents the radar echo LFM signal E r The initial frequency of the radar echo LFM signal E r The chirp rate.

[0047] The arbitrary waveform generator module further converts the FDM signal into an analog signal for driving the IQ modulation module 104 of the integrated signal generating unit.

[0048] The integrated signal generating unit includes a device such as a photodiode for generating a continuous optical carrier E c , the optical carrier is expressed as:

[0049] Among them, E0 represents the optical carrier E c The amplitude, f c The optical carrier E c frequency;

[0050] The integrated signal generating unit further modulates the analog signal formed by the FDM signal conversion to an optical carrier to form an optically coupled signal; since the source of the FDM signal is the LFM signal and the encrypted OFDM signal, at this time, the optically coupled signal has the characteristics of radar interference and secure communication.

[0051] The integrated signal generating unit specifically further includes: a first optical coupling module, an IQ modulation module, an erbium-doped fiber amplifier module, an optical phase modulation subunit, and a second optical coupling module;

[0052] The first optical coupling module divides the continuous optical carrier into two paths, which are input into the IQ modulation module and the optical phase modulation subunit respectively; Figure 1 As shown in FIG. 1 , the first optical coupling module is a 3dB optical coupling module OC1, which couples the continuous optical carrier E c Divided into upper and lower E c1 、E c2 , respectively transmitted to the IQ modulation module and the optical phase modulation subunit.

[0053] Among them, E c1In the optical path: the IQ modulation module modulates the analog signal onto the optical carrier to form an optical signal. Specifically, in the IQ modulation module, IQ modulation is implemented through MATLAB offline programming to generate and drive OFDM signals and LFM signals, and these two signals are integrated together through frequency division multiplexing (FDM) technology. The IQ modulation module modulates the FDM signal onto the optical carrier and outputs the signal E I / Q It can be expressed as:

[0054]

[0055]

[0056]

[0057] Among them, J n (n=0,1) represents the first kind of n-th order Bessel function, and m0 and m1 are modulation indices.

[0058] IQ modulation module output signal E I / Q The spectrum of Figure 3 shown.

[0059] On the other hand, E c2 In the optical path, the optical phase modulation subunit is driven by two identical sawtooth wave signals to perform optical phase modulation on the optical carrier; the optical phase modulation subunit is composed of a dual-parallel dual-drive Mach-Zehnder modulation module and a waveform generator module; wherein the waveform generator module is used to generate two identical sawtooth waves, and the dual-parallel dual-drive Mach-Zehnder modulation module is driven by two identical sawtooth wave signals generated by the waveform generator, biasing the DC at the maximum transmission point to realize Serrodyne modulation of the continuous optical carrier.

[0060] The waveform generator module generates two sawtooth wave signals S t The dual-parallel dual-drive Mach-Zehnder modulation module at the maximum transmission point is driven to work. At this time, the dual-parallel dual-drive Mach-Zehnder modulation module is equivalent to an optical phase modulator, which can apply frequency shift to the LFM signal to generate radar interference, thereby ensuring the safety of one's own side.

[0061] Specifically, the waveform generator module generates two identical sawtooth wave signals S t , which can be expressed as:

[0062]

[0063] Where A represents the amplitude of the sawtooth wave, t represents the time dimension in the time domain, and T S Represents the period of the sawtooth wave, T F Indicates the fall time of the sawtooth wave.

[0064] Specifically, when the waveform fall time of the sawtooth signal is less than 1% of the signal period, the spurious signal suppression ratio of the dual-parallel dual-drive Mach-Zehnder modulation module to the optical carrier Serrodyne modulation is greater than 40 dB.

[0065] Ideally, the fall time T of the sawtooth signal F Approaching 0: Let the sawtooth wave amplitude A = 2V π , the optical carrier is frequency-shifted to the positive first-order sideband fc+fs by the dual-parallel dual-drive Mach-Zehnder modulation module 106 without power loss, and the output signal E DDMZM It can be expressed as:

[0066]

[0067] Wherein, a1 is the amplitude of the optical signal output by the dual-parallel dual-drive Mach-Zehnder modulation module.

[0068] Mach-Zehnder modulation module output signal E DDMZM The spectrum of Figure 4 shown.

[0069] Furthermore, E c1 The optical path also includes an erbium-doped fiber amplifier module for amplifying the optical signal E I / Q , to compensate for the insertion loss of the modulator;

[0070] The output signal E of the IQ modulation module I / Q After being amplified by the erbium-doped fiber amplifier module, the output signal E I / Q ′, and E c2 The output signal E of the dual parallel dual drive Mach-Zehnder modulation module in the optical path DDMZM The signal I is obtained by coupling through the second optical coupling module c .

[0071] The second optical coupling module is Figure 1 The optical coupling module OC2 in the embodiment couples the optical signals output by the IQ modulation module and the dual parallel dual drive Mach-Zehnder modulation module to form an optical coupling signal I c , whose spectrum is Figure 5 shown.

[0072] The signal transmission unit is used to transmit the optical coupling signal I c Converted into electrical signal I t , and process and transmit electrical signals.

[0073] The signal transmission unit includes a photoelectric detection module and a Ka-band horn antenna module;

[0074] Among them, the photoelectric detection module couples the optical signal I c Converted into electrical signal I t , electrical signal I t The electric spectrum of Figure 6 As shown in the figure, the RF radar interference signal and the chaotic encrypted OFDM signal are respectively at f0-f s and f RF -f s The photoelectric detection module outputs a signal I t It can be expressed as:

[0075]

[0076] Wherein, R represents the sensitivity of the photodetector module.

[0077] The Ka-band horn antenna module is used to filter out the part of the electrical signal outside the Ka-band, and transmit the processed electrical signal to the free space for transmission. At the same time, in order to ensure the quality of wireless transmission of the system's transmitted signal, an electrical amplifier is used to amplify the signal power before the Ka-band horn antenna module wirelessly transmits the signal.

[0078] The present invention proposes an integrated radar jamming and secure communication system based on microwave photons. Through this system, active jamming of enemy radars and encryption of one's own wireless communication signals are simultaneously achieved. The system has the advantages of wide operating frequency band, flexible adjustment, little influence of electromagnetic interference and low loss, etc., overcoming the limitations of traditional electronics. Due to the integration of multiple signals, the problem of spectrum congestion is further solved.

[0079] The above disclosures are only several specific embodiments of the present invention; however, the present invention is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A microwave photon-based radar jamming and security communication integrated system, characterized in that: include: An arbitrary waveform generator module (103), an integrated signal generating unit and a signal transmission unit; The arbitrary waveform generator module (103) is used to generate an OFDM signal and an LFM signal, integrate the OFDM signal and the LFM signal into an FDM signal, and then convert the FDM signal into an analog signal; The integrated signal generating unit is used to generate a continuous optical carrier, modulate the analog signal to the optical carrier, and form an optical coupling signal; the optical coupling signal has radar interference and safety communication characteristics; The signal transmission unit is used to convert the optical coupling signal into an electrical signal, and process and transmit the electrical signal.

2. The integrated system according to claim 1, characterized in that: Before the arbitrary waveform generator module (103) integrates the OFDM signal and the LFM signal into an FDM signal, it obtains an encrypted OFDM signal, wherein the encrypted OFDM signal is obtained by performing OFDM signal modulation on the encrypted QAM information. A multi-volume Jerk chaotic system is used to encrypt the I and Q branches of the QAM signal to generate an encrypted QAM signal.

3. The integrated system according to claim 1, characterized in that: The encrypted QAM information is implemented by encrypting a multi-volume Jerk chaotic system, including: Generate a set of chaotic sequences {x, y, z} using a multi-volume Jerk chaotic system; The initial values ​​{x0, y0, z0} are used as the shareable key to generate three chaotic sequences {x, y, z}; The original pseudo-random bit sequence is first subjected to a chaotic XOR operation with the chaotic sequence {z}; QAM mapping is performed after the chaotic XOR operation; The chaotic sequence {x}, {y} is used to encrypt the I and Q branches of the QAM signal, which is expressed as: S' = (real[S] +bx)+j(imag[S]+by), where S' represents the encrypted QAM signal, S represents the original QAM signal, and b represents the multiplication factor.

4. The integrated system according to claim 3, characterized in that: The chaotic system is realized by a set of ordinary differential equations, which can be expressed as:

5. The integrated system according to claim 1, characterized in that: The integrated signal generating unit comprises: a first optical coupling module, an IQ modulation module (104), an erbium-doped fiber amplifier module (105), an optical phase modulation subunit and a second optical coupling module; The first optical coupling module divides the continuous optical carrier into two paths, which are input into the IQ modulation module (104) and the optical phase modulation subunit respectively; The IQ modulation module (104) modulates the analog signal onto the optical carrier to form an optical signal; The erbium-doped fiber amplifier module (105) is used to amplify the optical signal to compensate for the insertion loss of the modulator; The optical phase modulation subunit is driven by two identical sawtooth wave signals to perform optical phase modulation on the optical carrier; The second optical coupling module is used to couple the optical signals output by the IQ modulation module and the optical phase modulation subunit.

6. The integrated system according to claim 5, characterized in that: The optical phase modulation subunit is composed of a dual parallel dual-drive Mach-Zehnder modulation module and a waveform generator module; The waveform generator module is used to generate two identical sawtooth waves. The dual parallel dual drive Mach-Zehnder modulation module (106) is driven by the two identical sawtooth wave signals generated by the waveform generator module (107), and the direct current is biased at the maximum transmission point to realize Serrodyne modulation of the continuous optical carrier.

7. The integrated system according to claim 6, characterized in that: When the waveform fall time of the sawtooth signal wave is less than 1% of the signal period, the spurious signal suppression ratio of the dual parallel dual drive Mach-Zehnder modulation module (106) to the optical carrier Serrodyne modulation is greater than 40 dB.

8. The integrated system according to claim 1, characterized in that: The signal transmission unit comprises a photoelectric detection module (109) and a Ka-band horn antenna module (110); The photoelectric detection module (109) is used to convert the optical coupling signal into an electrical signal; The Ka-band horn antenna module (110) is used to filter out the portion of the electrical signal outside the Ka-band and transmit it into free space for transmission.

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