Integrated microwave photon radar system integrating target detection and frequency measurement

Abstract

The present invention discloses an integrated microwave photon radar system integrating target detection and frequency measurement, which comprises a frequency measurement receiving unit, a signal generating and processing unit, a radar transmitting unit, a radar receiving unit, a first photoelectric detector and a signal acquisition and processing unit; the signal generating and processing unit is used to generate a radar transmitting signal based on a single-frequency optical carrier signal and to modulate and filter the frequency signal to be measured, and the signal acquisition and processing unit is used to process the frequency signal to be measured to obtain the frequency information of the signal and to obtain the target parameters through the target callback signal. The present invention constructs an integrated microwave photon radar system integrating target detection and frequency measurement; the present invention also utilizes a polarization multiplexing method to greatly simplify the complexity of the system while ensuring the system performance, and easily realizes the reconfiguration of the output waveform by changing the parameters of the external injection signal.

Description

Technical Field

[0001] The invention relates to the field of optoelectronic technology, and in particular to an integrated microwave photon radar system integrating target detection and frequency measurement. Background Art

[0002] With the diversification and miniaturization of space targets, higher requirements are placed on the radar operating frequency band and bandwidth. However, the performance of existing analog-to-digital converters and digital-to-analog converters cannot be improved rapidly. Therefore, due to the bottleneck of electronic technology, traditional microwave radars can no longer meet the needs of radar for target detection, identification and imaging. With the development of microwave photonics, the advantages of optoelectronic technology and devices in high-frequency, large-bandwidth microwave signal generation and processing can easily break through the limitations of traditional microwave radars in this regard, greatly improve the detection and identification capabilities of radars, and point out the direction for the development of radars.

[0003] Research on microwave photon radar systems began in 2014. After Italian researchers first reported the all-optical radar system, domestic researchers have conducted in-depth research on microwave photon radar systems. The Institute of Electronics of the Chinese Academy of Sciences, Nanjing University of Aeronautics and Astronautics, Tsinghua University and other institutions have reported radar systems based on microwave photon technology, realizing ultra-wideband imaging radar systems, distributed radar systems and other systems that can be used in different application scenarios. In addition, frequency measurement technology based on microwave photon technology has also developed rapidly, not only realizing frequency measurement within the ultra-wideband range, but also improving the measurement accuracy through optoelectronic combination.

[0004] The measurement of the received signal frequency is particularly important in electronic warfare. Although the traditional frequency measurement method has high detection accuracy, it is also unable to achieve wideband measurement. On the other hand, the integrated radar and frequency measurement solution based on microwave photonic technology has also been reported recently, but it is still in its infancy, and its ability to simultaneously achieve high-performance radar target detection and wideband high-precision frequency measurement is still limited. Therefore, studying an integrated system that can meet the current radar requirements for target detection and frequency measurement has become a current research hotspot. Summary of the invention

[0005] The purpose of the present invention is to provide an integrated microwave photon radar system integrating target detection and frequency measurement, so as to solve the problem that the current microwave photon radar has relatively single functions.

[0006] In order to achieve the purpose, the technical solution provided by the present invention is:

[0007] The present invention relates to an integrated microwave photon radar system integrating target detection and frequency measurement, which comprises:

[0008] A frequency measurement receiving unit, used for receiving and transmitting a frequency signal to be measured to a signal generating and processing unit;

[0009] A signal generation and processing unit, used to generate a radar transmission signal and an optical local oscillator signal based on a single-frequency optical carrier signal, and to perform modulation and filtering processing on the frequency signal to be measured;

[0010] A radar transmitting unit, used for receiving a radar transmitting signal generated by the signal generating and processing unit and transmitting the radar transmitting signal to a target;

[0011] A radar receiving unit, used for receiving a target reflected echo signal;

[0012] A modulator, used to receive the target reflected echo signal from the radar receiving unit and the optical local oscillator signal generated by the signal generation and processing unit, and modulate the target reflected echo signal and the optical local oscillator signal;

[0013] The first photoelectric detector is used for mixing and receiving the modulated target reflected echo signal and the optical local oscillator signal;

[0014] The signal acquisition and processing unit is used to process the frequency signal to be measured to obtain the frequency information of the signal, and obtain the target parameters based on the signal mixed and received by the photoelectric detector.

[0015] Preferably, the signal generation and processing unit also realizes reconstruction of the radar transmission signal waveform by injecting an external electrical signal source.

[0016] Preferably, the signal generation processing unit comprises:

[0017] A laser for generating a single-frequency optical carrier signal;

[0018] An electro-optical modulator is used to modulate the microwave signal to be measured onto an optical carrier and perform electro-optical conversion on the feedback signal;

[0019] A polarization beam splitter is used to split two beams of light with orthogonal polarization directions, where the two beams of light are respectively the light in two polarization directions after the laser is modulated by an electro-optic modulator;

[0020] The second photoelectric detector is used to convert the optical signal obtained by modulating the frequency signal to be measured by the electro-optical modulator into an electrical signal again, and transmit the electrical signal to the signal acquisition and processing unit;

[0021] A first delay optical fiber, used for delaying the single-frequency optical carrier signal;

[0022] An optical coupler is used to split the single-frequency optical carrier signal, wherein one beam is transmitted toward the radar transmitting unit, and the other beam is transmitted toward the modulator as an optical local oscillator signal;

[0023] A second delay optical fiber, used for delaying the optical local oscillator signal;

[0024] a third photoelectric detector, for converting the light beam transmitted to the radar transmitting unit and forming an electrical signal;

[0025] A first electric power beam splitter, used for beam splitting the electric signal, transmitting one of the electric signals to the radar transmitting unit, and feeding the other electric signal back to the electro-optical modulator;

[0026] An electrical signal source is used to generate a microwave signal and inject the microwave signal into the electro-optic modulator.

[0027] Preferably, the electrical signal source is connected to the electro-optical modulator via a second electrical power beam splitter, and the electrical signal fed back to the electro-optical modulator by the first electrical power beam splitter is also connected to the electro-optical modulator via the second electrical power beam splitter.

[0028] Preferably, an optical filter is further provided between the polarization beam splitter and the second photodetector, and the optical filter is used to filter the optical signal obtained by converting the frequency signal to be measured by the electro-optical modulator.

[0029] Preferably, an electrical amplifier is provided between the third photodetector and the first electrical power beam splitter for amplifying the electrical signal converted by the third photodetector.

[0030] Preferably, an optical fiber amplifier is provided between the second delay optical fiber and the modulator, and the optical fiber amplifier is used to amplify the optical local oscillator signal.

[0031] Preferably, the frequency measurement receiving unit comprises:

[0032] A frequency signal receiving antenna to be measured, used for receiving the frequency signal to be measured;

[0033] The measured frequency signal electric amplifier is used to amplify the measured frequency signal;

[0034] The frequency signal bandpass filter to be measured is used to filter the frequency signal to be measured.

[0035] Preferably, the radar transmitting unit comprises:

[0036] Radar transmission signal bandpass filter, used for filtering radar transmission signal;

[0037] A radar transmission signal electric amplifier, used to amplify the radar transmission signal;

[0038] Radar transmitting antenna, used to transmit radar transmission signal to the target.

[0039] Preferably, the radar receiving unit comprises:

[0040] Radar signal receiving antenna, used to receive target reflected echo signal;

[0041] Radar receiving signal electric amplifier, used to amplify the target reflected echo signal;

[0042] The radar receiving signal bandpass filter is used to filter the target reflected echo signal.

[0043] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0044] 1. The integrated microwave photon radar system for target detection and frequency measurement of the present invention comprises a signal generation processing unit and a signal acquisition processing unit. The signal generation processing unit is used to generate a radar transmission signal based on a single-frequency optical carrier signal and to modulate and filter the frequency signal to be measured. The signal acquisition processing unit is used to process the frequency signal to be measured to obtain the frequency information of the signal and to obtain the target parameters through the target callback signal, thereby constructing a microwave photon radar system for target detection and frequency measurement.

[0045] 2. The signal generation and processing unit in the integrated microwave photon radar system for target detection and frequency measurement of the present invention comprises a laser for generating a single-frequency optical carrier signal, an electro-optical modulator for modulating a microwave signal to be measured onto an optical carrier and performing electro-optical conversion on a feedback signal, a second photoelectric detector for splitting two light beams with orthogonal polarization directions and placing them into a polarization beam splitter, for reconverting the optical signal obtained by modulating the frequency signal to be measured by the electro-optical modulator into an electrical signal and transmitting the electrical signal to the signal acquisition and processing unit, a first delay optical fiber for delaying the single-frequency optical carrier signal, an optical coupler for performing beam splitting processing on the single-frequency optical carrier signal, a second delay optical fiber for delaying the optical local oscillator signal, a third photoelectric detector for converting the light beam transmitted to the radar transmitting unit and forming an electrical signal, and a first electric power beam splitter for splitting the electrical signal. Based on the above structure, the polarization multiplexing method can be used to greatly simplify the complexity of the system while ensuring the system performance.

[0046] 3. The integrated microwave photon radar system for target detection and frequency measurement involved in the present invention also has an electrical signal source arranged in the signal generation and processing unit. The electrical signal source is used to generate microwave signals and inject the microwave signals into the electro-optical modulator. The output waveform can be easily reconfigured by changing the parameters of the external injection signal. The system has the advantages of simple adjustment method, fast response, and the ability to achieve high-precision detection and frequency measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1This is a schematic diagram of the principle of an integrated microwave photon radar system that combines target detection and frequency measurement;

[0048] Figure 2 Detailed structural diagram of an integrated microwave photon radar system that combines target detection and frequency measurement.

[0049] Illustration: 1-frequency measurement receiving unit, 11-receiving antenna for the frequency signal to be measured, 12-electric amplifier for the frequency signal to be measured, 13-bandpass filter for the frequency signal to be measured, 2-signal generation and processing unit, 20-electric signal source, 21-laser, 22-electro-optic modulator, 23-polarization beam splitter, 231-optical filter, 24-second photoelectric detector, 25-first delay optical fiber, 26-optical coupler, 27-second delay optical fiber, 271-optical fiber amplifier, 28-third photoelectric detector, 281-electric amplifier, 29-first electric power beam splitter, 291-second electric power beam splitter, 3-radar transmitting unit, 31-radar transmitting signal bandpass filter, 32-radar transmitting signal electric amplifier, 33-radar transmitting antenna, 4-radar receiving unit, 41-radar signal receiving antenna, 42-radar receiving signal electric amplifier, 43-radar receiving signal bandpass filter, 5-modulator, 6-first photoelectric detector, 7-signal acquisition and processing unit. DETAILED DESCRIPTION

[0050] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with examples. The following examples are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0051] Refer to the attached Figure 1 As shown, the present invention relates to an integrated microwave photon radar system integrating target detection and frequency measurement, comprising a frequency measurement receiving unit 1, a signal generation processing unit 2, a radar transmitting unit 3, a radar receiving unit 4, a modulator 5, a first photodetector 6 and a signal acquisition processing unit 7. The signal generation processing unit 2 is connected to the output port of the frequency measurement receiving unit 1, the optical input port of the signal acquisition processing unit 7, the radar transmitting unit 3 and the radar receiving unit 4 respectively, the output port of the radar receiving unit 4 is connected to the radio frequency input port of the modulator 5, the optical output port of the modulator 5 is connected to the input port of the first photodetector 6, and the output port of the first photodetector 6 is connected to the signal acquisition processing unit 7.

[0052] The frequency measurement receiving unit 1 is used to receive and transmit the frequency signal to be measured to the signal generating and processing unit; the signal generating and processing unit 2 is used to generate a radar transmitting signal and an optical local oscillator signal based on a single-frequency optical carrier signal, modulate and filter the frequency signal to be measured, and reconstruct the radar transmitting signal waveform by injecting an external electrical signal source; the radar transmitting unit 3 is used to receive the radar transmitting signal generated by the signal generating and processing unit and transmit the radar transmitting signal to the target; the radar receiving unit 4 is used to receive the target reflected echo signal; the modulator 5 is used to receive the target reflected echo signal from the radar receiving unit and the optical local oscillator signal generated by the signal generating and processing unit, and modulate the target reflected echo signal and the optical local oscillator signal; the first photodetector 6 is used to mix and receive the modulated target reflected echo signal and the optical local oscillator signal; the signal acquisition processing unit 7 is used to process the frequency signal to be measured to obtain the frequency information of the signal, and obtain the target parameters based on the signal mixed and received by the photodetector.

[0053] Specifically, the signal generation and processing unit 2 is mainly composed of an optoelectronic oscillator, and the signal generation and processing unit 2 includes a laser 21, an electro-optical modulator 22 (dual-polarization dual-parallel Mach-Zehnder modulator), a polarization beam splitter 23, an optical filter 231, a second photodetector 24, a first delay optical fiber 25, an optical coupler 26, an optical fiber amplifier 271 (erbium-doped fiber amplifier), a third photodetector 28, an electrical amplifier 281, a first electrical power beam splitter 29, a second electrical power beam splitter 291 and an electrical signal source 20. Among them, the output of the laser 21 is connected to the input of the electro-optical modulator 22, the optical output port of the electro-optical modulator 22 is connected to the input port of the polarization beam splitter 23, a part of the output port of the polarization beam splitter 23 is connected to the optical filter 231, the output end of the optical filter 231 is connected to the optical input section of the second photodetector 24, and the electrical output end of the second photodetector 24 is connected to the input end of the signal acquisition processing unit 7; another part of the polarization beam splitter 23 is connected to the first delay optical fiber 25, the output port of the first delay optical fiber 25 is connected to the input port of the optical coupler 26, and the output port of the optical coupler 26 is connected to the input port of the third photodetector 28 and the second The delay optical fiber 27 is connected, the output optical port of the third photodetector 28 is connected to the input port of the electric amplifier 281, the output port of the electric amplifier 281 is connected to the input port of the first electric power beam splitter 29, the first electric power beam splitter 29 is an electric coupler, the output port of the first electric power beam splitter 29 is respectively connected to the radar transmitting unit 3 and the input port of the second electric power beam splitter 291, the second electric power beam splitter 291 is also an electric coupler, the output port of the second electric power beam splitter 291 is connected to a radio frequency input port of the electro-optical modulator 22, and the other input port of the second electric power beam splitter 291 is connected to the input port of the electric signal source 20.

[0054] The above-mentioned laser 21 is used to generate a single-frequency optical carrier signal; the electro-optical modulator 22 is used to modulate the microwave signal to be measured onto the optical carrier and perform electro-optical conversion on the feedback signal; the polarization beam splitter 23 is used to split two beams of light with orthogonal polarization directions, and the two beams of light are respectively the light in two polarization directions after the laser is modulated by the electro-optical modulator; the optical filter 231 is used to filter the optical signal obtained by converting the frequency signal to be measured by the electro-optical modulator; the second photodetector 24 is used to reconvert the optical signal obtained by modulating the frequency signal to be measured by the electro-optical modulator into an electrical signal, and transmit the electrical signal to the signal acquisition and processing unit 7; the first delay optical fiber 25 is used to delay the single-frequency optical carrier signal; the optical coupler 26 is used to filter the single-frequency optical carrier signal The optical fiber 27 is used to delay the optical local oscillator signal; the optical fiber amplifier 271 is used to amplify the optical local oscillator signal; the third photodetector 28 is used to convert the light beam transmitted to the radar transmitting unit and form an electrical signal; the electrical amplifier 281 is used to amplify the electrical signal converted by the third photodetector; the first electric power beam splitter 29 is used to split the electrical signal, transmit one of the electrical signals to the radar transmitting unit, and feed the other electrical signal back to the electro-optical modulator; the electrical signal source 20 is used to generate a microwave signal and inject the microwave signal into the electro-optical modulator.

[0055] The above-mentioned first delay optical fiber 25 and second delay optical fiber 27 can adopt single-mode optical fiber with a length of 1m-10000m; the optical fiber amplifier 271 can adopt an erbium-doped fiber amplifier or a semiconductor optical amplifier; the first light detector 6, the second light detector 24, and the third light detector 28 can be photodetectors with a bandwidth of 1-100GHz or other types of photodetectors that can achieve the same effect as a 1-100GHz photodetector; the bandwidth of the electric amplifier 281 is 10kHz-100GHz; the working bandwidth of the first electric power splitter 29 and the second electric power splitter 291 is 0.1-100GHz, and other electric power splitters with a working bandwidth of 0.1-100GHz and the same effect can also be used.

[0056] Refer to the attached Figure 1As shown, the frequency measurement receiving unit 1 includes: a frequency signal receiving antenna 11 to be measured, for receiving the frequency signal to be measured; a frequency signal electric amplifier 12 to be measured, for amplifying the frequency signal to be measured; and a frequency signal bandpass filter 13 to be measured, for filtering the frequency signal to be measured. The radar transmitting unit 3 includes: a radar transmitting signal bandpass filter 31 to filter the radar transmitting signal; a radar transmitting signal electric amplifier 32 to amplify the radar transmitting signal; and a radar transmitting antenna 33 to transmit the radar transmitting signal to the target. The radar receiving unit 41 includes: a radar signal receiving antenna 41 to receive the target reflected echo signal; a radar receiving signal electric amplifier 42 to amplify the target reflected echo signal; and a radar receiving signal bandpass filter 43 to filter the target reflected echo signal.

[0057] The working principle of the integrated microwave photon radar system integrating target detection and frequency measurement according to the present invention is as follows: Figure 2 As shown in the figure, the light emitted by the laser 21 is modulated by the electro-optic modulator 22, split by the polarization beam splitter 23, and then delayed by the first delay optical fiber 25. A part of the light is sent to the electric amplifier 281 for amplification after being photoelectrically converted by the photoelectric detector 28. A part of the amplified signal is sent to the radar transmitting unit 3, and the other part is sent back to the electro-optic modulator 22 to form a closed loop to constitute an optoelectronic oscillator structure, wherein the signal generated by the electric signal source 20 is coupled into the oscillation loop through the second electric power beam splitter 291, thereby realizing injection locking. When the system works in the radar detection mode, the frequency measurement receiving unit 1 stops working, and the target reflected echo signal received by the radar receiving unit 4 is modulated onto the modulator 5. The optical signal transmitted in the modulator 5 is the coupled signal of the optoelectronic oscillator optical path part, which is delayed and amplified by the second delay optical fiber 27. The optical signal is used as the optical local oscillator signal of the radar receiving branch. Finally, the radar receiving branch signal is mixed and received on the first photoelectric detector 6 and sent to the signal acquisition processing unit 7 for processing to obtain the target parameters such as distance, azimuth and other information. By changing the parameters such as the carrier frequency, bandwidth, period and power of the injected electrical signal, the radar transmission waveform can be flexibly reconstructed. On the other hand, when the system works in the frequency measurement mode, the radar receiving unit 4 stops working, and the signal to be measured received by the frequency measurement receiving unit 1 is modulated by the electro-optical modulator 22, and then output to the optical filter 231 through the upper branch of the polarization beam splitter 23 for filtering, and finally sent to the signal acquisition processing unit 7 after photoelectric conversion in the second photodetector 24, and the microwave signal to be measured is processed to obtain the frequency information of the signal.

[0058] The present invention is described in detail above in conjunction with the embodiments, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. An integrated microwave photon radar system integrating target detection and frequency measurement, characterized in that: It includes: A frequency measurement receiving unit, used for receiving and transmitting a frequency signal to be measured to a signal generating and processing unit; A signal generation and processing unit, used to generate a radar transmission signal and an optical local oscillator signal based on a single-frequency optical carrier signal, and to perform modulation and filtering processing on the frequency signal to be measured; The signal generation processing unit comprises: A laser for generating a single-frequency optical carrier signal; An electro-optical modulator is used to modulate the microwave signal to be measured onto an optical carrier and perform electro-optical conversion on the feedback signal; A polarization beam splitter is used to split two beams of light with orthogonal polarization directions, where the two beams of light are respectively the light in two polarization directions after the laser is modulated by an electro-optic modulator; The second photoelectric detector is used to convert the optical signal obtained by modulating the frequency signal to be measured by the electro-optical modulator into an electrical signal again, and transmit the electrical signal to the signal acquisition and processing unit; A first delay optical fiber, used for delaying the single-frequency optical carrier signal; An optical coupler is used to split the single-frequency optical carrier signal, wherein one beam is transmitted toward the radar transmitting unit, and the other beam is transmitted toward the modulator as an optical local oscillator signal; A second delay optical fiber, used for delaying the optical local oscillator signal; a third photoelectric detector, for converting the light beam transmitted to the radar transmitting unit and forming an electrical signal; A first electric power beam splitter, used for beam splitting the electric signal, transmitting one of the electric signals to the radar transmitting unit, and feeding the other electric signal back to the electro-optical modulator; an electrical signal source, used for generating a microwave signal and injecting the microwave signal into the electro-optical modulator; A radar transmitting unit, used for receiving a radar transmitting signal generated by the signal generating and processing unit and transmitting the radar transmitting signal to a target; A radar receiving unit, used for receiving a target reflected echo signal; A modulator, used to receive the target reflected echo signal from the radar receiving unit and the optical local oscillator signal generated by the signal generation and processing unit, and modulate the target reflected echo signal and the optical local oscillator signal; The first photoelectric detector is used for mixing and receiving the modulated target reflected echo signal and the optical local oscillator signal; The signal acquisition and processing unit is used to process the frequency signal to be measured to obtain the frequency information of the signal, and obtain the target parameters based on the signal mixed and received by the photoelectric detector.

2. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1 is characterized in that: The signal generation and processing unit also realizes reconstruction of the radar transmission signal waveform by injecting an external electrical signal source.

3. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1 is characterized in that: The electric signal source is connected to the electro-optic modulator via a second electric power beam splitter, and the electric signal fed back to the electro-optic modulator by the first electric power beam splitter is also connected to the electro-optic modulator via the second electric power beam splitter.

4. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1, characterized in that: An optical filter is also provided between the polarization beam splitter and the second photoelectric detector, and the optical filter is used to filter the optical signal obtained by converting the frequency signal to be measured by the electro-optical modulator.

5. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1 is characterized in that: An electrical amplifier is also provided between the third photoelectric detector and the first electrical power beam splitter, for amplifying the electrical signal converted by the third photoelectric detector.

6. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1, characterized in that: An optical fiber amplifier is also provided between the second delay optical fiber and the modulator, and the optical fiber amplifier is used to amplify the optical local oscillator signal.

7. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1, characterized in that: The frequency measurement receiving unit comprises: A frequency signal receiving antenna to be measured, used for receiving the frequency signal to be measured; The measured frequency signal electric amplifier is used to amplify the measured frequency signal; The frequency signal bandpass filter to be measured is used to filter the frequency signal to be measured.

8. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1, characterized in that: The radar transmitting unit comprises: Radar transmission signal bandpass filter, used for filtering radar transmission signal; A radar transmission signal electric amplifier, used to amplify the radar transmission signal; Radar transmitting antenna, used to transmit radar transmission signal to the target.

9. The integrated microwave photon radar system for target detection and frequency measurement according to claim 1, characterized in that: The radar receiving unit comprises: Radar signal receiving antenna, used to receive target reflected echo signal; Radar receiving signal electric amplifier, used to amplify the target reflected echo signal; The radar receiving signal bandpass filter is used to filter the target reflected echo signal.

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