Microwave photon ultra-wideband imaging device and method

Abstract

The present invention discloses a microwave photon ultra-wideband imaging device and method, which belongs to the field of microwave photon signal processing technology. The device generates ultra-wideband imaging signals through optical frequency doubling technology, and adopts an adaptive de-skewing receiving and processing method of a distance-guided high-precision adjustable optical delay line, assisted by an inverse synthetic aperture imaging algorithm to achieve ultra-wideband long-distance high-precision imaging of small targets. By using optical frequency doubling technology, the bandwidth of narrow-band intermediate frequency-driven imaging signals of the MHz order is increased to the GHz order; by using a high-precision electrically controlled adjustable optical delay line, adaptive optical delay matching is achieved; by using photon mixing technology, ultra-wideband optical de-skewing reception is achieved; by using an inverse synthetic aperture imaging processing algorithm of pulse accumulation, long-distance, high-precision, and high-resolution imaging processing of small target signals is achieved. The present invention can be applied to the generation and reception processing of various complex signals in the fields of radar, communication, and electronic warfare, and has the advantages of broadband, long distance, and high precision.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave photon signal processing, and in particular relates to a microwave photon ultra-wideband imaging device and method. Background Art

[0002] Traditional radar imaging systems based on electronics face rate and bandwidth bottlenecks, making it difficult to generate stable ultra-wideband signals, which in turn restricts radar imaging accuracy. Although radar imaging technology has made some progress in high-resolution radar target detection, there are still problems such as limited signal bandwidth, short imaging distance of continuous wave systems, and mismatched reception delay of long-distance pulse detection radar signals. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a microwave photon ultra-wideband imaging device and method, which combines photon technology with microwave technology, utilizes the advantages of optics such as broadband, high speed, and parallelism, and can generate ultra-wideband waveform signals of several GHz to achieve centimeter-level ultra-high resolution radar images, thereby providing more information details about the target and achieving the recognition and detection accuracy of small targets.

[0004] The object of the present invention is achieved through the following technical solutions:

[0005] A microwave photon ultra-wideband imaging device, comprising:

[0006] A narrowband imaging signal generating unit, wherein the narrowband imaging signal generating unit generates an original signal, wherein the original signal is a MHz-level intermediate frequency narrowband driving imaging signal;

[0007] An optical frequency doubling unit, wherein the optical frequency doubling unit includes multiple frequency doubling stages, each frequency doubling stage includes a modulator and a detector, the first frequency doubling stage undergoes electro-optical modulation of the original signal, and the modulator is controlled to work in a carrier suppression state, the electro-optically modulated signal is photoelectrically converted by the detector, and a frequency doubling linear frequency modulation signal is generated, and the frequency doubling linear frequency modulation signal is electro-optically modulated on the next frequency doubling stage, the optically-carried microwave signal formed by the electro-optical modulation in the last frequency doubling stage is input into the adaptive optical delay matching unit as a reference optical signal, and the frequency doubling linear frequency modulation signal generated in the last frequency doubling stage is used as a transmission signal;

[0008] An adaptive optical delay matching unit, which detects the object to be detected and performs delay matching on the echo signal and the reference light signal;

[0009] An ultra-wideband optical de-skew receiving unit, wherein the ultra-wideband optical de-skew receiving unit electro-optically modulates the reference optical signal after delay matching with the echo signal of the transmission signal, and generates a pulse de-skew signal through broadband optical de-skew;

[0010] A high-precision imaging signal processing unit converts the pulse de-skew signal into a digital signal, and then collects and stores the pulse accumulation signal to achieve target two-dimensional imaging.

[0011] Furthermore, the narrowband imaging signal generating unit includes a DDS processing unit.

[0012] Furthermore, the optical frequency doubling unit is a combination of cascaded electro-optical modulators, and the modulators are all biased at a carrier suppression operating point.

[0013] Furthermore, the output end of the detector also includes an electrical signal amplifier and an electrical filtering module.

[0014] Furthermore, the adaptive optical delay matching unit includes a single-frequency pulse transceiver module and an adjustable optical delay component. The single-frequency pulse transceiver module detects the object to be detected to obtain the distance information of the target, and the adjustable optical delay component realizes the delay matching of the echo signal and the reference optical signal.

[0015] Furthermore, the high-precision imaging signal processing unit uses an inverse aperture imaging processing algorithm to achieve two-dimensional imaging of the target.

[0016] Furthermore, the optical frequency doubling unit includes three levels of frequency doubling.

[0017] Furthermore, the adjustable optical delay component includes an electrically controlled adjustable optical delay line or a multi-bit adjustable optical delay loop.

[0018] On the other hand, the present invention further provides a microwave photon ultra-wideband imaging method, which is implemented based on any of the above-mentioned microwave photon ultra-wideband imaging devices, and the method comprises:

[0019] A narrow-band imaging signal generating unit is used to generate a MHz-level intermediate frequency narrow-band driving imaging signal, and then the driving imaging signal is generated into a GHz-level ultra-wideband imaging signal as a transmitting signal through an optical frequency doubling unit, and a reference optical signal is output;

[0020] Using an adaptive optical delay matching unit to obtain distance information of the target and complete delay matching between the echo signal of the transmission signal and the reference optical signal;

[0021] The echo signal is modulated onto light using an ultra-wideband optical de-skew receiving unit, and coupled and beat with the delayed reference optical signal to achieve ultra-wideband optical de-skew reception and obtain a pulse de-skewed receiving signal with time delay matching.

[0022] A high-precision imaging signal processing unit is used to convert the delay-matched pulse de-skew signal into a digital signal, and the pulse accumulation signal is collected and stored, and the target two-dimensional imaging is achieved based on the stored pulse accumulation signal.

[0023] The beneficial effects of the present invention are:

[0024] The present invention combines optical frequency doubling technology, photon mixing technology and pulse accumulation inverse aperture imaging processing, and uses a high-precision electrically controlled adjustable optical delay line to achieve adaptive delay matching based on the pulse system for long-distance and high-resolution imaging detection of tiny targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural block diagram of a microwave photon ultra-wideband imaging device according to an embodiment of the present invention;

[0026] Figure 2 It is a principle block diagram of the microwave photon ultra-wideband imaging method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0028] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0029] Traditional radar imaging systems based on electronics face rate and bandwidth bottlenecks, making it difficult to generate stable ultra-wideband signals, which in turn restricts radar imaging accuracy. Although radar imaging technology has made some progress in high-resolution radar target detection, there are still problems such as limited signal bandwidth, short imaging distance of continuous wave systems, and mismatched reception delay of long-distance pulse detection radar signals.

[0030] In order to solve the above technical problems, the following embodiments of the microwave photon ultra-wideband imaging device and method of the present invention are proposed.

[0031] Example 1

[0032] Reference Figure 1 ,like Figure 1The figure shows a structural block diagram of the microwave photon ultra-wideband imaging device of this embodiment, which includes a narrowband imaging signal generating unit, an optical frequency doubling unit, an adaptive optical delay matching unit, an ultra-wideband optical de-skew receiving unit and a high-precision imaging signal processing unit.

[0033] Specifically, the narrowband imaging signal generating unit generates an original signal, which is a MHz-level intermediate frequency narrowband driving imaging signal.

[0034] In this embodiment, the DDS generates an original signal and enters the optical frequency doubling unit. In this embodiment, the frequency of the original signal is a 1.5-2.25 GHz linear frequency modulation signal.

[0035] The optical frequency doubling unit includes multiple frequency doubling stages, each of which includes a modulator and a detector. The first frequency doubling stage undergoes electro-optical modulation of the original signal, and the modulator is controlled to work in a carrier suppression state. After the electro-optically modulated signal is photoelectrically converted by the detector, a frequency doubling linear frequency modulation signal is generated, and the frequency doubling linear frequency modulation signal is used to electro-optically modulate the next frequency doubling stage. The optical microwave signal formed by the electro-optical modulation in the last frequency doubling stage is input into the adaptive optical delay matching unit as a reference optical signal, and the frequency doubling linear frequency modulation signal generated in the last frequency doubling stage is used as a transmission signal. The optical frequency doubling unit is a combination of cascaded electro-optical modulators, and the modulators are all biased at the carrier suppression operating point.

[0036] In this embodiment, the original signal electro-optically modulates the optical carrier emitted by the laser, controls the modulator to work in a carrier suppression state, and generates a 3-4.5 GHz linear frequency modulation signal after photoelectric conversion by the detector, completing the first level of frequency doubling. Similarly, after the second and third levels of frequency doubling, 6-9 GHz and 12-18 GHz linear frequency modulation signals are generated respectively, 12-18 GHz is the transmission signal, and in the third level of frequency doubling, the optically-carried microwave signal formed by the electro-optical modulation is input into the adaptive optical delay matching unit as a reference optical signal.

[0037] The adaptive optical delay matching unit detects the object to be measured and performs delay matching on the echo signal and the reference optical signal. The adaptive optical delay matching unit is a combination of a single-frequency pulse transceiver module and an adjustable optical delay component. The adjustable optical delay component can be an electrically controlled adjustable optical delay line or a multi-bit adjustable optical delay loop.

[0038] In this embodiment, the single-frequency pulse transceiver module detects the object to be detected, uses the single-frequency pulse signal autocorrelation technology to obtain the distance information of the target, and uses the electrically controlled adjustable optical delay line to achieve delay matching between the echo signal and the reference optical signal.

[0039] The ultra-wideband optical de-skew receiving unit includes a single-wavelength laser, an electro-optical modulator, an optical coupler and a photodetector. The echo signal of the transmitted signal is used to electro-optically modulate the reference optical signal after delay matching, and a pulse de-skew signal is generated after broadband optical de-skew.

[0040] In this embodiment, the 12-18 GHz echo signal electro-optically modulates the delay-matched reference optical signal, filters out one of the sidebands through an optical filter, and performs broadband optical de-skew after photoelectric detection to generate a pulse de-skew signal.

[0041] The high-precision imaging signal processing unit converts the pulse de-skew signal into a digital signal, and then collects and stores the pulse accumulation signal to achieve target two-dimensional imaging.

[0042] In this embodiment, the analog pulse de-skew signal output by the photodetector is converted into a digital signal by a high-speed processor, and then the pulse accumulation signal of the millisecond level is collected and stored. Finally, the inverse aperture imaging processing algorithm is used to achieve long-distance, high-precision and high-resolution two-dimensional imaging of small targets.

[0043] Example 2

[0044] This embodiment is based on the microwave photon ultra-wideband imaging device provided in the above embodiment and proposes a microwave photon ultra-wideband imaging method. Figure 2 ,like Figure 2 The figure is a principle block diagram of the microwave photon ultra-wideband imaging method of this embodiment, which mainly includes ultra-wideband imaging signal generation, adaptive optical delay matching, ultra-wideband optical de-skew reception and high-precision imaging signal processing.

[0045] Among them, ultra-wideband imaging signal generation: represents the signal to be transmitted, an adjustable narrowband imaging signal can be generated by electrical equipment, and an ultra-wideband imaging signal can be generated by optical frequency doubling means.

[0046] Adaptive optical delay matching: Use the target distance information to generate a matching optical path delay.

[0047] Ultra-wideband optical de-skewed reception: The echo signal is modulated onto light, coupled and beat with the reference light signal after optical path delay to obtain a pulse de-skewed signal.

[0048] High-precision imaging signal processing: The delayed-matched pulse de-skewed signal is collected through the digital signal processing module, and the long pulse accumulation signal of the millisecond level is stored. Finally, the inverse aperture imaging processing algorithm of pulse accumulation is used to achieve long-distance, high-precision and high-resolution two-dimensional imaging of tiny targets.

[0049] Therefore, the microwave photon ultra-wideband imaging method of this embodiment specifically includes the following steps:

[0050] Step 1: Use the narrowband imaging signal generating unit to generate a MHz-level intermediate frequency narrowband driving imaging signal, then use the optical frequency doubling unit to generate the driving imaging signal into a GHz-level ultra-wideband imaging signal as a transmitting signal, and output a reference optical signal.

[0051] Step 2: Use the adaptive optical delay matching unit to obtain the distance information of the target and complete the delay matching between the echo signal of the transmitted signal and the reference light signal.

[0052] Step 3: Use an ultra-wideband optical de-skew receiving unit to modulate the echo signal onto light, couple and beat the delayed reference optical signal to achieve ultra-wideband optical de-skew reception, and obtain a delay-matched pulse de-skew receiving signal.

[0053] Step 4: Use a high-precision imaging signal processing unit to convert the delay-matched pulse de-skew signal into a digital signal, collect and store the pulse accumulation signal, and achieve target two-dimensional imaging based on the stored pulse accumulation signal.

[0054] This embodiment combines optical frequency doubling technology, photon mixing technology and pulse accumulation inverse aperture imaging processing, and uses a high-precision electrically controlled adjustable optical delay line to achieve adaptive delay matching based on the pulse system for long-distance and high-resolution imaging detection of tiny targets.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microwave photon ultra-wideband imaging device, characterized in that: The device comprises: A narrowband imaging signal generating unit, wherein the narrowband imaging signal generating unit generates an original signal, wherein the original signal is a MHz-level intermediate frequency narrowband driving imaging signal; An optical frequency doubling unit, wherein the optical frequency doubling unit includes multiple frequency doubling stages, each frequency doubling stage includes a modulator and a detector, the first frequency doubling stage electro-optically modulates the light-carrying microwave signal through the modulator via the original signal, and controls the modulator to work in a carrier suppression state, and the signal after electro-optical modulation is photoelectrically converted by the detector to generate a frequency-doubled linear frequency modulation signal, and the frequency-doubled linear frequency modulation signal is used to electro-optically modulate the light-carrying microwave signal of the next frequency doubling stage through the modulator, and the light-carrying microwave signal formed by the electro-optical modulation in the last frequency doubling stage is input into the adaptive optical delay matching unit as a reference optical signal, and the frequency-doubled linear frequency modulation signal generated in the last frequency doubling stage is used as a transmission signal; An adaptive optical delay matching unit, wherein the adaptive optical delay matching unit detects the object to be measured and performs delay matching on the echo signal and the reference optical signal. The adaptive optical delay matching unit comprises a single-frequency pulse transceiver module and an adjustable optical delay component. The single-frequency pulse transceiver module detects the object to be measured and obtains distance information of the target. Based on the distance information, the adjustable optical delay component realizes delay matching between the echo signal and the reference optical signal. The adjustable optical delay component includes an electrically controlled adjustable optical delay line or a multi-bit adjustable optical delay loop; An ultra-wideband optical de-skew receiving unit, which modulates the echo signal onto the reference optical signal after delay matching, and generates a pulse de-skew signal through broadband optical de-skew; A high-precision imaging signal processing unit converts the pulse de-skew signal into a digital signal, and then collects and stores the pulse accumulation signal to achieve target two-dimensional imaging.

2. The microwave photon ultra-wideband imaging device according to claim 1, characterized in that: The narrowband imaging signal generating unit includes a DDS processing unit.

3. The microwave photon ultra-wideband imaging device according to claim 1, characterized in that: The optical frequency doubling unit is a combination of cascaded electro-optical modulators, and the modulators are all biased at a carrier suppression working point.

4. The microwave photon ultra-wideband imaging device according to claim 1, characterized in that: The output end of the detector also includes an electric signal amplifier and an electric filter module.

5. The microwave photon ultra-wideband imaging device according to claim 1, characterized in that: The high-precision imaging signal processing unit uses an inverse aperture imaging processing algorithm to achieve two-dimensional imaging of the target.

6. The microwave photon ultra-wideband imaging device according to claim 1, characterized in that: The optical frequency doubling unit includes three levels of frequency doubling.

7. A microwave photon ultra-wideband imaging method, characterized in that: The method is implemented based on the microwave photon ultra-wideband imaging device according to any one of claims 1 to 6, and the method comprises: A narrow-band imaging signal generating unit is used to generate a MHz-level intermediate frequency narrow-band driving imaging signal, and then the driving imaging signal is generated into a GHz-level ultra-wideband imaging signal as a transmitting signal through an optical frequency doubling unit, and a reference optical signal is output; Using an adaptive optical delay matching unit to obtain distance information of the target and complete delay matching between the echo signal of the transmission signal and the reference light signal; The echo signal is modulated onto light using an ultra-wideband optical de-skew receiving unit, and coupled and beat with the delayed reference optical signal to achieve ultra-wideband optical de-skew reception and obtain a pulse de-skewed receiving signal with time delay matching. A high-precision imaging signal processing unit is used to convert the delay-matched pulse de-skew signal into a digital signal, and the pulse accumulation signal is collected and stored, and the target two-dimensional imaging is achieved based on the stored pulse accumulation signal.

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