Microwave photon digital sum-difference beam forming device and method

Abstract

The invention discloses a microwave photon receiver digital sum-difference beam forming device and method, and the method comprises the steps: employing the approximation of an optical delay beam multi-beam forming method and a fast Fourier transform multi-beam forming method, and setting a specific optical beam forming network delay value consistent with the delay of the fast Fourier transform multi-beam forming method; a beam value is converted into a digital channel signal by using inverse Fourier transform, a sum-difference beam is formed by using a multiply-accumulate method, and the system comprises an active area array, an optical beam forming network, a photoelectric conversion module, a channel data recovery module and a digital sum-difference beam forming module. According to the method, additional hardware equipment is not needed, the digital sum and difference beams are calculated by utilizing the generated multi-beam reduction channel digital signals covering all directions, and the method has the characteristics of easiness in implementation, flexibility, reliability and the like.

Description

Technical Field

[0001] The invention belongs to the field of microwave photon technology and radar phased array technology, and specifically relates to a microwave photon digital sum and difference beamforming device and method. Background Art

[0002] In recent years, microwave photonic technology has been widely used in radar and communication systems. By compensating the aperture transit time by real-time delay in the optical domain, wide-bandwidth angular scanning of phased array radar can be achieved. At the same time, optical true time-delay transmission has inherent advantages such as low loss, wide bandwidth, and anti-electromagnetic interference. Therefore, optical true time-delay transmission has become an important direction for the development of phased array radar.

[0003] Arbitrary pointing and difference beams are usually used in application scenarios such as radiation source positioning. Most microwave photon radars use optical true delay methods for beam forming. Since it is difficult to achieve negative value adjustment in true delay systems, difference beam forming is a key factor restricting the application of microwave photon radars. Summary of the invention

[0004] The purpose of the present application is to provide a microwave photon digital sum and difference beam forming device to solve the technical problem that microwave photon radar difference beam is difficult to realize in the prior art.

[0005] The technical solution to achieve the purpose of the present invention is: a microwave photon receiver digital sum and difference beamforming device, including an active array, an optical beamforming network, an optoelectronic conversion module, a channel data recovery module, and a digital sum and difference beamforming module; wherein,

[0006] The active array is used to receive spatial radiation signals and modulate the radio frequency signals onto optical carriers of different wavelengths after amplification and filtering. The optical carriers of different wavelengths are synthesized and output to an optical beam forming network.

[0007] The optical beam forming network is used to optically process the optical carrier containing the radio frequency information and form an optical beam signal;

[0008] The photoelectric conversion module is used to convert the optical beam signal into a digital beam signal;

[0009] The channel data recovery module is used to convert the beam signal into channel data through inverse Fourier transform;

[0010] The digital sum-difference beamforming module is used to convert channel data into digital sum-difference beams using a multiplication-accumulation method, and adjust a digital phase shift value to change a beam pointing angle.

[0011] Preferably, the active array includes an antenna unit, a radio frequency receiving component, an electro-optical modulator and a first wavelength division multiplexer, the antenna unit is used to receive a spatial radiation signal, the radio frequency receiving component is used to amplify and filter the spatial radiation signal received by the antenna unit, the electro-optical modulator is used to modulate the radio frequency signal onto an optical carrier, and the first wavelength division multiplexer is used to synthesize optical carriers of different wavelengths into one.

[0012] Preferably, the number of optical carriers is the same as the number of active area array channels.

[0013] Preferably, the optical beam forming network includes a second wavelength division multiplexer and N optical delay networks, the second wavelength division multiplexer is used to de-wavelength division multiplex one optical carrier to form N optical carriers with different wavelengths, and each optical delay network is used to delay and add the optical carrier containing radio frequency information to form an optical beam signal.

[0014] The present invention also proposes a microwave photon digital sum and difference beamforming method, comprising:

[0015] After receiving the spatial radiation signal and amplifying and filtering it, the RF signal is modulated onto optical carriers of different wavelengths. The optical carriers of different wavelengths are synthesized and output to the optical beam forming network.

[0016] Optically processing the optical carrier containing the radio frequency information and forming an optical beam signal;

[0017] Converting an optical beam signal into a digital beam signal;

[0018] The beam signal is converted into channel data by inverse Fourier transform;

[0019] The channel data is converted into a digital sum-difference beam using the multiplication-accumulation method, and the digital phase shift value is adjusted to change the beam pointing angle.

[0020] Compared with the prior art, the present invention has the following significant advantages:

[0021] The present invention does not require additional hardware equipment. It uses the generated signal to cover all directions while restoring the channel digital signal with multiple beams to further calculate the digital sum and difference beams. It has the characteristics of being easy to implement, flexible and reliable, and provides a technical approach for forming sum and difference beams in true delay arrays such as microwave photonic radars. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the microwave photon digital sum and difference beamforming device in the present invention.

[0023] Figure 2 It is a signal flow chart of the microwave photon digital sum and difference beamforming device and method in the present invention. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 , 2 As shown, in order to meet the requirements of the full azimuth interception function, multiple beams covering all angles are usually formed in azimuth; microwave photon radar usually uses an optical delay network to form beams, and multiple beams covering all angles can be generated through multiple parallel optical delay networks; digital beamforming radar usually uses a simultaneous multi-beam method based on fast Fourier transform to generate multiple digital beams covering all angles.

[0026] A microwave photon receiver digital sum and difference beamforming method, using the approximation of an optical delay beam multi-beamforming method and a fast Fourier transform multi-beamforming method, by setting a specific optical beamforming network delay value consistent with the delay of the fast Fourier transform multi-beamforming method, using inverse Fourier transform to convert the beam value into a digital channel signal, and then using a multiplication-accumulation method to form a sum and difference beam, comprising an active array, an optical beamforming network, an optoelectronic conversion module, a channel data recovery module, and a digital sum and difference beamforming module; wherein,

[0027] The active array includes an antenna unit, a radio frequency receiving component, an electro-optical modulator and a wavelength division multiplexer. The antenna unit receives the spatial radiation signal, the radio frequency receiving component performs amplification and filtering, the electro-optical modulator modulates the radio frequency signal onto an optical carrier, and the wavelength division multiplexer synthesizes optical carriers of different wavelengths into one channel.

[0028] The optical beam forming network includes a wavelength division multiplexer and an optical delay network, and has the function of synthesizing multiple optical carriers into multiple optical beam signals, performing optical processing such as wavelength division demultiplexing, delay, and addition on the optical carriers containing radio frequency information to form an optical beam signal identical to the radio frequency channel;

[0029] The photoelectric conversion module includes a photoelectric conversion module and an analog-to-digital conversion module, and has the function of converting the optical beam signal into a digital signal. The photoelectric conversion module converts the optical beam signal into an electric beam signal, and the analog-to-digital conversion module converts the analog electric beam signal into a digital beam signal.

[0030] The channel data recovery module has the function of converting the beam signal into channel data by inverse Fourier transform.

[0031] The digital sum-difference beamforming module has the ability to convert channel data into sum-difference beams, uses the multiplication-accumulation method to convert channel data into digital sum-difference beams, and adjusts the digital phase shift value to change the beam pointing angle.

[0032] In a further embodiment, the optical delay network adopts a uniform step delay, and the delay step is

[0033]

[0034] In a further embodiment, the original channel digitized data is realized by using the inverse Fourier transform of the beam data, and the inverse transform formula is:

[0035]

[0036] Where r(k) is the kth original channel signal, and b(n) is the nth beam signal.

[0037] In a further embodiment, the digital sum-difference beamforming is implemented using a multiplication-accumulation method, and the sum-difference beamforming formula is as follows:

[0038]

[0039] A microwave photon digital sum-difference beamforming method, comprising:

[0040] After receiving the spatial radiation signal and amplifying and filtering it, the RF signal is modulated onto optical carriers of different wavelengths. The optical carriers of different wavelengths are synthesized and output to the optical beam forming network.

[0041] Optically processing the optical carrier containing the radio frequency information and forming an optical beam signal;

[0042] Converting an optical beam signal into a digital beam signal;

[0043] The beam signal is converted into channel data by inverse Fourier transform;

[0044] The channel data is converted into a digital sum-difference beam using the multiplication-accumulation method, and the digital phase shift value is adjusted to change the beam pointing angle.

[0045] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages:

[0046] The present invention is based on the similarity of the principle of the optical delay beamforming method and the phase shift digital beamforming method. By setting the optical delay value corresponding to the FFT simultaneous multi-beam phase shift value, multiple digital beams pointing the same as the FFT simultaneous multi-beam are obtained, and then the digital signal of the original channel is obtained by IFFT transformation, and then the digital beam is formed by the multiplication and accumulation method. The method does not require additional hardware equipment, and uses the generated multi-beam digital signal to restore the channel to calculate the digital sum and difference beams. It has the characteristics of easy implementation, flexibility and reliability, and provides a technical approach for the formation of sum and difference beams by true delay arrays such as microwave photon radars.

Claims

1. A digital sum and difference beamforming device for a microwave photon receiver, characterized in that: It includes an active array, an optical beamforming network, an optoelectronic conversion module, a channel data recovery module, and a digital sum and difference beamforming module; wherein, The active array is used to receive spatial radiation signals and modulate the radio frequency signals onto optical carriers of different wavelengths after amplification and filtering. The optical carriers of different wavelengths are synthesized and output to an optical beam forming network. The optical beam forming network is used to optically process the optical carrier containing the radio frequency signal and form an optical beam signal; The photoelectric conversion module is used to convert the optical beam signal into a digital beam signal; The channel data recovery module is used to convert the digital beam signal into channel data through inverse Fourier transform; The digital sum-difference beamforming module is used to convert channel data into digital sum-difference beams using a multiplication-accumulation method, and adjust a digital phase shift value to change a beam pointing angle.

2. The digital sum and difference beamforming device for a microwave photon receiver according to claim 1, characterized in that: The active array includes an antenna unit, a radio frequency receiving component, an electro-optical modulator and a first wavelength division multiplexer. The antenna unit is used to receive a spatial radiation signal. The radio frequency receiving component is used to amplify and filter the spatial radiation signal received by the antenna unit. The electro-optical modulator is used to modulate the radio frequency signal onto an optical carrier. The first wavelength division multiplexer is used to synthesize optical carriers of different wavelengths into one.

3. The digital sum and difference beamforming device for a microwave photon receiver according to claim 1, characterized in that: The number of optical carriers is the same as the number of active array channels.

4. The digital sum and difference beamforming device for a microwave photon receiver according to claim 1, characterized in that: The optical beam forming network includes a second wavelength division multiplexer and N optical delay networks. The second wavelength division multiplexer is used to de-wavelength-division multiplex one optical carrier to form N optical carriers with different wavelengths. Each optical delay network is used to delay and add the optical carrier containing radio frequency information to form an optical beam signal.

5. The digital sum and difference beamforming device for a microwave photon receiver according to claim 4, characterized in that: The number of optical delay networks is the same as the number of active array channels.

6. The digital sum and difference beamforming device for a microwave photon receiver according to claim 4, characterized in that: The optical delay network adopts uniform step delay, and the delay step is: Where Δd is the delay step, N is the number of optical delay networks, k is the beam number, and λ is the wavelength of the signal to be measured.

7. The digital sum and difference beamforming device for a microwave photon receiver according to claim 1, characterized in that: The specific formula of the channel data recovery module converting the beam signal into channel data through inverse Fourier transform is: Among them, r(n) is the nth original channel signal, b(k) is the beam signal output by the kth photoelectric conversion module, and N is the number of active array channels.

8. The digital sum and difference beamforming device for a microwave photon receiver according to claim 1, characterized in that: The numbers and beamforming formulas are as follows: θ is the sum beam pointing, r(n) is the nth original channel signal, λ is the wavelength of the signal to be measured, and N is the number of active array channels.

9. The digital sum and difference beamforming device for a microwave photon receiver according to claim 1, characterized in that: The difference beamforming formula is as follows: θ is the sum beam pointing, r(n) is the nth original channel signal, λ is the wavelength of the signal to be measured, and N is the number of active array channels.

10. A microwave photon receiver digital sum and difference beamforming method based on the device of any one of claims 1 to 9, characterized in that: include: After receiving the spatial radiation signal and amplifying and filtering it, the RF signal is modulated onto optical carriers of different wavelengths. The optical carriers of different wavelengths are synthesized and output to the optical beam forming network. Optically processing the optical carrier containing the radio frequency information and forming an optical beam signal; Converting an optical beam signal into a digital beam signal; The beam signal is converted into channel data by inverse Fourier transform; The channel data is converted into a digital sum-difference beam using the multiplication-accumulation method, and the digital phase shift value is adjusted to change the beam pointing angle.

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