Radar, communication and spectrum sensing integrated device and method based on photon technology

Abstract

The invention discloses a radar, communication and spectrum sensing integrated device and method based on the photon technology. Radio frequency amplitude keying signals and linear frequency modulation signals are modulated to the two sides of an optical carrier through double parallel Mach-Zehnder modulators respectively; a positive first-order optical sideband of the amplitude keying signal and a negative first-order optical sideband of the chirp signal are generated. The linear frequency modulation optical sideband is modulated by a to-be-measured signal and then acts on a narrow-band optical filter provided by stimulated Brillouin scattering gain, and frequency information is mapped into time domain pulses, so that spectrum sensing is realized. The amplitude keying light sideband and the linear frequency modulation light sideband are subjected to beat frequency detection through a photoelectric detector to generate an amplitude keying linear frequency modulation electric signal, and then radar detection and communication are achieved through dechirp processing and envelope detection respectively. Radar, communication and spectrum sensing functions are integrated on the basis of the photon technology, high-speed wireless communication, rapid high-precision target sensing and spectrum sensing can be achieved at the same time, and the method has good practical application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of communication and perception technology, and specifically relates to a radar, communication, and spectrum perception integrated device and method based on photonic technology. Background Art

[0002] Integrating various sensing functions and artificial intelligence into 6G networks, enabling interconnection between humans, machines, and objects through 6G, will provide a solid digital infrastructure for new applications. A recommended solution for incorporating diverse sensing and communication functions into 6G is to integrate radar, wireless communications, and spectrum sensing into a unified system. In this system, radar technology is used to detect targets, while spectrum sensing analyzes the electromagnetic spectrum of the surrounding environment. This integrated system, known as a radar, communication, and spectrum sensing system, has been studied in the electrical domain. However, due to the poor tunability and reconfigurability of electrical domain systems, traditional electrical domain solutions have encountered bottlenecks in generating complex, broadband, high-frequency waveforms, making them difficult to meet the demands of high data rates and high resolution applications. Microwave photonics, due to its many advantages, including wide bandwidth, high frequency, low loss, excellent tunability, and resistance to electromagnetic interference, has attracted considerable attention in academic research. Over the past few decades, microwave photonics has been widely used in advanced radar, communication, and spectrum sensing systems.

[0003] Microwave photonics technology is mainly used in the field of communications to generate, process and transmit high-frequency and high-speed wireless communication signals in 5G or 6G systems. In addition, microwave photonics technology is also used to improve radar system performance and increase spectrum sensing bandwidth and speed. Based on the research on single-function radar, wireless communication and spectrum sensing systems based on microwave photonics technology, multifunctional systems based on microwave photonics technology have also been further studied, such as radar communication integrated systems and radar spectrum sensing integrated systems. In photon-assisted radar communication integrated systems, radar communication integrated waveform generation is crucial. In radar communication integrated systems, radar signals and communication signals can be generated separately and multiplexed together through frequency division and time division. In order to achieve a truly integrated signal waveform, orthogonal phase shift keying signals and spectrum spread spectrum phase coding signals are used as radar communication integrated signals. In related research, a ranging resolution of 3.5 cm and a data transmission rate of 1 Gb / s can be achieved (IEEE Trans. Microw. Theory Techn., 70(9): 1552, 2022). However, the receivers of these two methods require a higher sampling rate. In order to reduce the receiver sampling rate, amplitude keying linear frequency modulation signals and orthogonal phase shift keying linear frequency modulation signals can be used in radar communication integrated systems and combined with de-chirping for processing (Optics & Laser Techn., 165: 109638, 2023). In photon-assisted radar spectrum sensing integrated systems, linear frequency modulation signals are usually used for radar detection and spectrum sensing. Radar functions are realized by de-chirping linear frequency modulation signals, and spectrum sensing functions are realized by combining linear frequency modulation signals with frequency-to-time mapping. Broadband linear frequency modulation signals can be obtained through methods such as photon doubling, photon quadrupling, and optical injection. In these radar spectrum sensing integrated systems, the minimum frequency measurement error is ±15MHz, and the best achievable distance resolution is 2.6cm (Opt. Lett., 44(8): 1948, 2019).

[0004] However, a system that can simultaneously integrate radar, communication, and spectrum sensing has not yet been studied. Therefore, it is necessary to design a high-speed and high-precision integrated radar, communication, and spectrum sensing system to simultaneously meet the application requirements of high-speed wireless communication, fast and high-precision target perception, and spectrum sensing. Summary of the Invention

[0005] The purpose of the present invention is to provide an integrated radar, communication, and spectrum sensing device and method based on photonic technology, meeting the requirements for the integration of multiple sensing functions and communications in 6G, thereby enabling interconnection between people, machines, and objects through 6G. In this invention, a dual-parallel Mach-Zehnder modulator modulates a radio frequency amplitude keying (RFAK) signal and a linear frequency modulation (LFM) signal onto either side of an optical carrier, generating positive first-order optical sidebands of the AAM signal and negative first-order optical sidebands of the LFM signal. The LFM optical sidebands, modulated by the signal to be measured, interact with a narrowband optical filter provided by the stimulated Brillouin scattering gain to map the frequency information into time-domain pulses, enabling spectrum sensing. The AAM optical sidebands and LFM optical sidebands are then detected by a photodetector to generate an AAM linear frequency modulation (LFM) electrical signal. De-skewing and envelope detection are then used to achieve radar detection and communication, respectively. This invention, based on photonic technology, integrates radar, communication, and spectrum sensing functions, enabling high-speed wireless communication, rapid and high-precision target sensing, and spectrum sensing. The invention has promising practical application prospects.

[0006] The specific technical solutions for implementing the present invention are as follows:

[0007] A radar, communication, and spectrum sensing integrated device based on photonic technology is characterized in that the device includes a continuous wave laser, a first optical power splitter, an amplitude keying signal source, a first 90-degree bridge, a linear frequency modulation signal source, a second 90-degree bridge, a first electrical coupler, a second electrical coupler, a first dual-parallel Mach-Zehnder modulator, a first erbium-doped fiber amplifier, a second optical power splitter, a Mach-Zehnder modulator, a first receiving antenna, a first electrical amplifier, an optical isolator, a nonlinear medium, an optical circulator, a single-tone radio frequency signal source, a third 90-degree bridge, a second dual-parallel Mach-Zehnder modulator, a second erbium-doped fiber amplifier, a first photodetector, a first analog-to-digital converter, a second photodetector, a second electrical amplifier, an electrical power splitter, a transmitting antenna, a second receiving antenna, a third electrical amplifier, an electrical mixer, a second analog-to-digital converter, a third receiving antenna, a fourth electrical amplifier, an envelope detector, and a third analog-to-digital converter.

[0008] The output port of the continuous wave laser is connected to the input port of the first optical power splitter, one output port of the first optical power splitter is connected to the optical input port of the first dual parallel Mach-Zehnder modulator, the output port of the amplitude keying signal source is connected to the input port of the first 90-degree bridge, and the output port of the linear frequency modulation signal source is connected to the input port of the second 90-degree bridge; the 0-degree output port of the first 90-degree bridge and the 90-degree output port of the second 90-degree bridge are respectively connected to the two input ports of the first electrical coupler, and the 90-degree output port of the first 90-degree bridge and the 90-degree output port of the second 90-degree bridge are respectively connected to the two input ports of the first electrical coupler. The 0-degree output port of the 0-degree bridge is respectively connected to the two input ports of the second electrical coupler, the output ports of the first electrical coupler and the second electrical coupler are respectively connected to the two RF input ports of the first dual-parallel Mach-Zehnder modulator, the optical output port of the first dual-parallel Mach-Zehnder modulator is connected to the input port of the first erbium-doped fiber amplifier, the output port of the first erbium-doped fiber amplifier is connected to the input port of the second optical power splitter; one output port of the second optical power splitter is connected to the optical input port of the Mach-Zehnder modulator, and the first receiving antenna receiving the signal to be measured is connected to the optical input port of the Mach-Zehnder modulator. The output port of the optical power divider is connected to the input port of the first electrical amplifier, the output port of the first electrical amplifier is connected to the radio frequency input port of the Mach-Zehnder modulator, the optical output port of the Mach-Zehnder modulator is connected to the input port of the optical isolator, the output port of the optical isolator is connected to the input port of the nonlinear medium, the output port of the nonlinear medium is connected to the optical circulator port II, the output port of the single-tone radio frequency signal source is connected to the input port of the third 90-degree bridge, the output port of the third 90-degree bridge is connected to the radio frequency input port of the second dual-parallel Mach-Zehnder modulator, another output port of the first optical power splitter is connected to the optical input port of the second dual-parallel Mach-Zehnder modulator, the optical output port of the second dual-parallel Mach-Zehnder modulator is connected to the input port of the second erbium-doped fiber amplifier, the output port of the second erbium-doped fiber amplifier is connected to the optical circulator port I, the optical circulator port III is connected to the input port of the first photodetector, the output port of the first photodetector is connected to the input port of the first analog-to-digital converter, and the frequency or time-frequency information of the signal to be measured is obtained by processing the frequency information and mapping it into pulses in the time domain;Another output port of the second optical power splitter is connected to the input port of a second photodetector, the output port of the second photodetector is connected to the input port of a second electrical amplifier, the output port of the second electrical amplifier is connected to the input port of the electrical power splitter, one output port of the electrical power splitter is connected to the input port of a transmitting antenna, the echo signal reflected by the detection target is received by the second receiving antenna and injected into the input port of a third electrical amplifier, the output port of the third electrical amplifier is connected to the radio frequency port of an electrical mixer, another output port of the electrical power splitter is connected to the local oscillator port of the electrical mixer, the intermediate frequency port of the electrical mixer is connected to the input port of a second analog-to-digital converter, and imaging and distance information of the detection target are obtained by processing the de-skewed signal waveform; the communication signal is received by the third receiving antenna and injected into the input port of a fourth electrical amplifier, the output port of the fourth electrical amplifier is connected to the input port of an envelope detector, and the output port of the envelope detector is connected to the input port of the third analog-to-digital converter, and communication information can be directly obtained from the collected waveform.

[0009] In this device, a radio frequency amplitude keying (RFAK) signal and a linear frequency modulation (LFM) signal are modulated onto both ends of an optical carrier using suppressed carrier single sideband (SSB), generating the positive first-order optical sideband of the AAM signal and the negative first-order optical sideband of the LFM signal. The bandwidth of the AAM signal determines the communication rate, while the bandwidth of the LFM signal determines the radar resolution and instantaneous bandwidth of spectrum sensing.

[0010] In the device, the negative first-order optical sideband of the linear frequency modulation signal is used as a swept-frequency optical signal. After being modulated by the single-sideband carrier of the signal to be measured, it interacts with the narrowband optical filter provided by the stimulated Brillouin scattering gain to map the frequency information of the signal to be measured into time-domain pulses, thereby realizing the spectrum sensing function.

[0011] In the device, the positive first-order optical sideband of the amplitude keying signal and the negative first-order optical sideband of the linear frequency modulation signal are detected by the photoelectric detector to obtain an integrated amplitude keying linear frequency modulation signal for communication and radar detection.

[0012] In the device, the integrated amplitude keying linear frequency modulation signal is de-skewed and further processed to realize ranging and imaging functions, and the communication information is extracted through envelope detection.

[0013] A radar, communication, and spectrum sensing integrated method using the above device comprises the following steps:

[0014] 1) The center frequency of the continuous wave laser output is f cThe continuous light wave is divided into two equal parts by the first optical power divider, one part of which is input to the first dual-parallel Mach-Zehnder modulator. The first dual-parallel Mach-Zehnder modulator, the first 90-degree bridge, the second 90-degree bridge, the first electrical coupler and the second electrical coupler are used to suppress the carrier single sideband method to change the center frequency of the RF amplitude keying signal source output to f RF The frequency range of the amplitude keying signal and linear frequency modulation signal source output is f a ~f b The linear frequency modulation signal is modulated to both sides of the optical carrier to generate a center frequency of f c +f RF The positive first-order optical sideband and frequency range of the amplitude-shifted keying signal are f c –f b ~f c –f a The negative first-order optical sideband of the linear frequency modulation signal.

[0015] 2) The optical signal output by the first dual-parallel Mach-Zehnder modulator is amplified by the first erbium-doped fiber amplifier and then divided into two equal parts by the second optical power splitter. One part of the optical signal is input to the Mach-Zehnder modulator, and then the optical signal is modulated in a suppressed carrier double-sideband manner by the signal to be measured received by the first receiving antenna and amplified by the first electrical amplifier. Since the optical signal output by the second optical power splitter contains a linear frequency modulated optical signal with a frequency of f SUT The signal to be measured is also converted into a swept frequency optical signal corresponding to the signal to be measured after modulation, wherein the negative first-order swept frequency optical sideband frequency band corresponding to the signal to be measured is f c –f b –f SUT ~f c –f a –f SUT ,Then these swept frequency optical signals are injected into the nonlinear medium after passing through the optical isolator.

[0016] 3) Another part of the optical signal output by the first optical power splitter is input to the second dual parallel Mach-Zehnder modulator, and the optical signal is output by the single-tone RF signal source with a frequency of f x The single-tone signal is modulated in a suppressed carrier single sideband manner to obtain a frequency of f c –f x Then, the optical signal output by the second dual-parallel Mach-Zehnder modulator is amplified by the second erbium-doped fiber amplifier, and then injected into the nonlinear medium through the port I and port II of the optical circulator in turn, generating a center frequency of f c –f x –f SBS The stimulated Brillouin scattering gain is used as a narrowband optical filter.

[0017] 4) The negative first-order swept optical sideband corresponding to the signal to be tested at different frequencies passes through the center frequency f c –f x –f SBS The narrowband optical filter is filtered out at a specific moment to obtain the corresponding optical pulse signal, thereby mapping the frequency information into a time domain pulse. The center frequency of the narrowband optical filter can be adjusted by f x The optical pulse signal passes through ports II and III of the optical circulator and is then injected into the first photodetector, which converts it into an electrical pulse signal. The electrical pulse signal is collected by the first analog-to-digital converter. The frequency information of the signal under test is obtained based on the time of occurrence of the obtained electrical pulse signal. Furthermore, by segmenting and rearranging multiple cycles of the electrical pulse signal, two-dimensional time-frequency information of the signal under test can be obtained.

[0018] 5) Another part of the optical signal output by the second optical power splitter is injected into the second photodetector to generate a center frequency of f RF +f a / 2+f b Amplitude-shifted linear frequency modulation (AFM) signal with a frequency of 1 / 2 is used for communication and radar detection. After being amplified by a second electrical amplifier, the AFM signal is split into two equal parts by an electrical power divider. One portion of the electrical signal output by the power divider is input to the local oscillator port of the electrical mixer, while the other portion of the signal output by the power divider is radiated into the surrounding space via the transmitting antenna. The echo signal reflected by the detected target is received by the second receiving antenna, amplified by a third electrical amplifier, and then input to the RF port of the electrical mixer. Mixing by the electrical mixer generates a de-skewed signal, which is then acquired by a second analog-to-digital converter. Processing of the acquired signal waveform yields the range and imaging results of the detected target.

[0019] 6) The amplitude-shifted linear frequency modulation signal received by the third receiving antenna is amplified by the fourth electrical amplifier, and the envelope waveform of the amplitude-shifted linear frequency modulation signal is obtained by the envelope detector. After the envelope waveform is collected by the third analog-to-digital converter, the bit information of the communication transmission can be restored after judgment.

[0020] The present invention proposes an integrated device and method for radar, communication, and spectrum sensing based on photonic technology. A radio frequency amplitude keying (RFAK) signal and a linear frequency modulation (LFM) signal are modulated onto either side of an optical carrier using a first dual-parallel Mach-Zehnder modulator, generating positive first-order optical sidebands of the RFAK signal and negative first-order optical sidebands of the LFM signal, thereby generating an integrated optical signal for radar, communication, and spectrum sensing. The negative first-order optical sidebands of the LFM signal and a narrowband optical filter provided by the stimulated Brillouin scattering effect are used to map the frequency of the signal to be measured into a time-domain pulse, thereby achieving spectrum sensing. The optical signal output by the first dual-parallel Mach-Zehnder modulator is then subjected to beat frequency detection by a photodetector to obtain an integrated amplitude keying (AK) linear frequency modulation (LFM) electrical signal for radar and communication. The AK linear frequency modulation (LFM) electrical signal is used for radar and communication. The echo signal reflected by the target is further processed by de-skewing to achieve target detection. Communication information extraction is achieved using an envelope detector. The present invention integrates radar, communication, and spectrum sensing functions based on photonic technology, while achieving high-speed wireless communication, rapid and high-precision target perception, and spectrum perception, providing an implementation method for the seamless integration of 6G's multi-dimensional perception and wireless communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the device of the present invention;

[0022] Figure 2 The result diagram of time-frequency analysis using the present invention is shown in FIG.

[0023] Figure 3 This is the result of inverse synthetic aperture radar imaging using the present invention.

[0024] Figure 4 The distance measurement result of two stationary objects using the present invention is shown in FIG.

[0025] Figure 5 The result diagram of communication using the present invention DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings and embodiments. The embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following embodiments.

[0027] See also Figure 1The device of the present invention comprises: a continuous wave laser 1, a first optical power splitter 2, an amplitude keying signal source 3, a first 90-degree bridge 4, a linear frequency modulation signal source 5, a second 90-degree bridge 6, a first electrical coupler 7, a second electrical coupler 8, a first dual parallel Mach-Zehnder modulator 9, a first erbium-doped fiber amplifier 10, a second optical power splitter 11, a Mach-Zehnder modulator 12, a first receiving antenna 13, a first electrical amplifier 14, an optical isolator 15, a nonlinear medium 16, an optical circulator 17, a single-tone transmitter Frequency signal source 18, third 90-degree bridge 19, second dual parallel Mach-Zehnder modulator 20, second erbium-doped fiber amplifier 21, first photodetector 22, first analog-to-digital converter 23, second photodetector 24, second electrical amplifier 25, electrical power divider 26, transmitting antenna 27, second receiving antenna 28, third electrical amplifier 29, electrical mixer 30, second analog-to-digital converter 31, third receiving antenna 32, fourth electrical amplifier 33, envelope detector 34, third analog-to-digital converter 35.

[0028] The output port of the continuous wave laser 1 is connected to the input port of the first optical power splitter 2, one output port of the first optical power splitter 2 is connected to the optical input port of the first dual parallel Mach-Zehnder modulator 9, the output port of the amplitude keying signal source 3 is connected to the input port of the first 90-degree bridge 4, the output port of the linear frequency modulation signal source 5 is connected to the input port of the second 90-degree bridge 6, the 0-degree output port of the first 90-degree bridge 4 and the 90-degree output port of the second 90-degree bridge 6 are connected to the two input ports of the first electrical coupler 7, the 90-degree output port of the first 90-degree bridge 4 and the 90-degree output port of the second 90-degree bridge 6 are connected to the The 0-degree output port is connected to the two input ports of the second electrical coupler 8, the output ports of the first electrical coupler 7 and the second electrical coupler 8 are respectively connected to the two RF input ports of the first dual-parallel Mach-Zehnder modulator 9, the optical output port of the first dual-parallel Mach-Zehnder modulator 9 is connected to the input port of the first erbium-doped fiber amplifier 10, the output port of the first erbium-doped fiber amplifier 10 is connected to the input port of the second optical power splitter 11; one output port of the second optical power splitter 11 is connected to the optical input port of the Mach-Zehnder modulator 12, and the output port of the first receiving antenna 13 that receives the signal to be measured is connected to the first receiving antenna 13 that receives the signal to be measured. The input port of the first electric amplifier 14 is connected to the radio frequency input port of the Mach-Zehnder modulator 12, the optical output port of the Mach-Zehnder modulator 12 is connected to the input port of the optical isolator 15, the output port of the optical isolator 15 is connected to the input port of the nonlinear medium 16, the output port of the nonlinear medium 16 is connected to the port II of the optical circulator 17, the output port of the single-tone radio frequency signal source 18 is connected to the input port of the third 90-degree bridge 19, the output port of the third 90-degree bridge 19 is connected to the radio frequency input port of the second dual parallel Mach-Zehnder modulator 20 The optical power splitter 2 is connected to the optical input port of the second dual-parallel Mach-Zehnder modulator 20, the optical output port of the second dual-parallel Mach-Zehnder modulator 20 is connected to the input port of the second erbium-doped fiber amplifier 21, the output port of the second erbium-doped fiber amplifier 21 is connected to the port I of the optical circulator 17, the port III of the optical circulator 17 is connected to the input port of the first photodetector 22, the output port of the first photodetector 22 is connected to the input port of the first analog-to-digital converter 23, and the frequency or time-frequency information of the signal to be measured is obtained by processing the collected waveform;Another output port of the second optical power splitter 11 is connected to the input port of the second photodetector 24, the output port of the second photodetector 24 is connected to the input port of the second electrical amplifier 25, the output port of the second electrical amplifier 25 is connected to the input port of the electrical power splitter 26, one output port of the electrical power splitter 26 is connected to the input port of the transmitting antenna 27, the echo signal reflected by the detection target is received by the second receiving antenna 28 and then injected into the input port of the third electrical amplifier 29, the output port of the third electrical amplifier 29 is connected to the radio frequency port of the electrical mixer 30, The other output port of the electrical power divider 26 is connected to the local oscillator port of an electrical mixer 30, and the intermediate frequency port of the electrical mixer 30 is connected to the input port of a second analog-to-digital converter 31. By processing the collected waveform, imaging and range information of the detected target are obtained. The communication signal is received by a third receiving antenna 32 and connected to the input port of a fourth electrical amplifier 33. The output port of the fourth electrical amplifier 33 is connected to the input port of an envelope detector 34. The output port of the envelope detector 34 is connected to the input port of a third analog-to-digital converter 35. Communication information can be directly obtained from the collected waveform.

[0029] The present invention simultaneously realizes high-speed communication, target detection and spectrum sensing, and the specific steps are as follows:

[0030] Step 1: The center frequency of the continuous wave laser output is f c The continuous light wave is divided into two equal parts by the first optical power divider, one part of which is input to the first dual-parallel Mach-Zehnder modulator. The first dual-parallel Mach-Zehnder modulator, the first 90-degree bridge, the second 90-degree bridge, the first electrical coupler and the second electrical coupler are used to suppress the carrier single sideband method to change the center frequency of the RF amplitude keying signal source output to f RF The frequency range of the amplitude keying signal and linear frequency modulation signal source output is f a ~f b The linear frequency modulation signal is modulated to both sides of the optical carrier to generate a center frequency of f c +f RF The positive first-order optical sideband and frequency range of the amplitude-shifted keying signal are f c –f b ~f c –f a The negative first-order optical sideband of the linear frequency modulation signal.

[0031] Step 2: The optical signal output by the first dual parallel Mach-Zehnder modulator is amplified by the first erbium-doped fiber amplifier and then divided into two equal parts by the second optical power splitter. One part of the optical signal is input to the Mach-Zehnder modulator, and then the optical signal is modulated in a suppressed carrier double-sideband manner by the signal to be measured received by the first receiving antenna and amplified by the first electrical amplifier. Since the optical signal output by the second optical power splitter contains a linear frequency modulated optical signal with a frequency of f SUT The signal to be measured is also converted into a swept frequency optical signal corresponding to the signal to be measured after modulation, wherein the negative first-order swept frequency optical sideband frequency band corresponding to the signal to be measured is f c –f b –f SUT ~f c –f a –f SUT ,Then these swept frequency optical signals are injected into the nonlinear medium after passing through the optical isolator.

[0032] Step 3: Another part of the optical signal output by the first optical power splitter is input to the second dual parallel Mach-Zehnder modulator. The optical signal is output by the single-tone RF signal source with a frequency of f x The single-tone signal is modulated in a suppressed carrier single sideband manner to obtain a frequency of f c –f x Then, the optical signal output by the second dual-parallel Mach-Zehnder modulator is amplified by the second erbium-doped fiber amplifier, and then injected into the nonlinear medium through the port I and port II of the optical circulator in turn, generating a center frequency of f c –f x –f SBS The stimulated Brillouin gain is used as a narrowband optical filter.

[0033] Step 4: The negative first-order swept optical sideband corresponding to the signal to be tested at different frequencies passes through the center frequency f c –f x –f SBS The narrowband optical filter is filtered out at a specific moment to obtain the corresponding optical pulse signal, thereby mapping the frequency information into a time domain pulse. The center frequency of the narrowband optical filter can be adjusted by f x The optical pulse signal passes through ports II and III of the optical circulator and is then injected into the first photodetector, which converts it into an electrical pulse signal. The electrical pulse signal is collected by the first analog-to-digital converter. The frequency information of the signal under test is obtained based on the time of occurrence of the electrical pulse signal. By segmenting and rearranging the electrical pulse signal over multiple cycles, two-dimensional time-frequency information of the signal under test can be obtained.

[0034] Step 5: Another part of the optical signal output by the second optical power splitter is injected into the second photodetector to generate a center frequency of f RF +f a / 2+f b Amplitude-keyed linear frequency modulation (AFM) signal with a frequency of / 2 is used for communication and radar detection. After being amplified by a second electrical amplifier, the AFM signal is split into two equal parts by an electrical power divider. One portion of the electrical signal output by the power divider is input to the local oscillator port of the electrical mixer, while the other portion of the signal output by the power divider is radiated into the surrounding space via the transmitting antenna. The echo signal reflected by the detected target is amplified by the second receiving antenna and amplified by a third electrical amplifier before being input to the RF port of the electrical mixer. Mixing by the electrical mixer generates a de-skewed signal, which is then acquired by a second analog-to-digital converter. Processing of the acquired signal waveform yields the range and imaging results of the detected target.

[0035] Step 6: After the amplitude-shifted keyed linear frequency modulation signal received by the third receiving antenna is amplified by the fourth electrical amplifier, an envelope detector is used to obtain the envelope waveform of the amplitude-shifted keyed linear frequency modulation signal. After the envelope waveform is collected by the third analog-to-digital converter, the bit information of the communication transmission can be restored after judgment.

[0036] Example

[0037] See also Figure 1 The specific implementation process of this embodiment is as follows:

[0038] Step 1: A continuous wave laser outputs a continuous optical carrier with a central wavelength of 1553.096 nm and a power of 16 dBm. This continuous optical carrier is divided equally into two parts by a first optical power splitter, one of which is input into a first dual-parallel Mach-Zehnder modulator. An amplitude keying (AMK) signal and a linear frequency modulation (LFM) signal are generated by an arbitrary waveform generator. The center frequency and baud rate of the AM signal are 3 GHz and 2 Gbaud, respectively, while the frequency range and period of the LFM signal are 4.8 to 10.8 GHz and 4 μs, respectively. The AM signal and LFM signal are input into a first 90-degree bridge and a second 90-degree bridge, respectively. The signals output from the 0-degree output port of the first 90-degree bridge and the 90-degree output port of the second 90-degree bridge are coupled via a first electrical coupler and then input into one RF port of the first dual-parallel Mach-Zehnder modulator. The signals output from the 90-degree output port of the first 90-degree bridge and the 0-degree output port of the second 90-degree bridge are coupled via a second electrical coupler and then input into the other RF port of the first dual-parallel Mach-Zehnder modulator. The two sub-modulators of the first dual-parallel Mach-Zehnder modulator are biased at the minimum transmission point, and the main modulator is biased at the orthogonal transmission point, realizing a modulation mode of suppressed carrier single sideband, generating a positive first-order optical sideband of an amplitude keying signal and a negative first-order optical sideband of a linear frequency modulation signal.

[0039] Step 2: The optical signal output by the first dual parallel Mach-Zehnder modulator is amplified by the first erbium-doped fiber amplifier and then divided into two equal parts by the second optical power splitter. One part of the optical signal is input to the Mach-Zehnder modulator and then modulated by the signal to be tested in a suppressed carrier double-sideband manner. The signal to be tested is generated by an arbitrary waveform transmitter and simulates the actual situation. Since the optical signal output by the second optical power splitter contains a linear frequency modulated optical signal with a frequency of f SUT The measured signal is modulated and converted into a swept-frequency optical signal corresponding to the measured signal, and then these swept-frequency optical signals are injected into the nonlinear medium after passing through the optical isolator.

[0040] Step 3: The single-tone RF signal source does not output a signal, and the second dual-parallel Mach-Zehnder modulator does not suppress the carrier, which is equivalent to f x = 0. Then, the optical signal output by the second dual-parallel Mach-Zehnder modulator is amplified by the second erbium-doped fiber amplifier and then injected into the nonlinear medium through ports I and II of the optical circulator in sequence, generating stimulated Brillouin scattering gain, which is used as a narrowband optical filter.

[0041] Step 4: In f x =0, the frequency band of spectrum sensing is 0-6 GHz. The negative first-order swept optical sidebands corresponding to the different frequency signals to be measured are filtered out at a specific time through a narrowband optical filter, obtaining the corresponding optical pulse signal, thereby mapping the frequency information into a time domain pulse. The optical pulse signal passes through ports II and III of the optical circulator in sequence, and is then injected into the first photodetector, converting the optical pulse signal into an electrical pulse signal. After the electrical pulse signal is collected by the first analog-to-digital converter, the frequency information of the signal to be measured can be obtained based on the occurrence time of the obtained electrical pulse signal. After the electrical pulse signal is divided and rearranged, the time-frequency two-dimensional information of the signal to be measured can be obtained. Figure 2 The time-frequency analysis diagram of different signals to be tested is shown. Figure 2 (a)–(e) are the time-frequency analysis results of a positive chirp linear FM signal with a signal period of 500 μs, a negative chirp linear FM signal, a triangular chirp linear FM signal, a nonlinear FM signal, and a signal with a “sine” time-frequency characteristic. Figure 2 (f) is the time-frequency analysis result of the stepped frequency signal with a signal period of 600μs.

[0042] Step 5. Another part of the optical signal output by the second optical power splitter is injected into the second photodetector to generate an amplitude-shifted linear frequency modulation signal with a center frequency of 7.8 GHz, which is used for communication and radar detection. After being amplified by the second electrical amplifier, the amplitude-shifted linear frequency modulation signal is divided into two equal parts by the electrical power splitter. One part of the electrical signal output by the electrical power splitter is input to the local oscillator port of the electrical mixer, and the other part of the electrical signal output by the electrical power splitter is radiated to the surrounding space through the transmitting antenna. The echo signal reflected by the detected target is received by the second receiving antenna and then amplified by the third electrical amplifier, and then input to the radio frequency port of the electrical mixer. Then, the electrical mixer outputs the de-skewed signal, which is then collected by the second analog-to-digital converter. The collected signal waveform is processed to obtain the ranging and imaging results of the detected target. Figure 3 The image clearly shows the inverse synthetic aperture imaging results of two cylinders and a cuboid, with the dimensions of the cuboid being 10 cm (length) × 8 cm (width) × 18 cm (height). Cylinder 1 has a diameter and height of 6.5 cm and 12 cm, respectively, while cylinder 2 has a diameter and height of 8 cm and 10 cm, respectively. Figure 4 The figure shows the distance measurement results when the two cylinders are used as two stationary targets. Based on the frequency interval of the two strongest frequency components in the figure, the distance between the two targets can be obtained. The maximum error between the measurement result and the actual value does not exceed 0.7 cm.

[0043] Step 6: After the amplitude-shifted keyed linear frequency modulation signal received by the third receiving antenna is amplified by the fourth electrical amplifier, an envelope detector is used to obtain the envelope waveform of the amplitude-shifted keyed linear frequency modulation signal. After the envelope waveform is collected by the third analog-to-digital converter, the bit information of the communication transmission can be restored after judgment. Figure 5 Communication measurement results are shown. Figure 5 (a) is the envelope waveform collected for 4 μs. Figure 5 (b) is the eye diagram corresponding to 5(a). Figure 5 (c) and (d) show the Figure 5 (a) shows the waveforms of the segments 0 to 0.05 μs and 3.95 to 4 μs. It can be seen that the envelope waveform can well represent the original bit information, and the communication function of the system is verified.

[0044] In conclusion, the above-described embodiment is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It should be noted that a person skilled in the art can make several equivalent variations and substitutions based on the content disclosed in the present invention. For example, the bandwidth and frequency band of the amplitude keying signal, the frequency band range of the linear frequency modulation signal, the f xThe value of can further change the bandwidth and frequency band of spectrum sensing, the frequency band of radar communication integrated signal, the resolution of radar detection and the communication rate; a broadband 90-degree bridge is used to replace the first 90-degree bridge, the second 90-degree bridge, the first electric coupler and the second electric coupler; these equivalent deformations, replacements and adjustments should also be considered as the scope of protection of the present invention.

Claims

1. A radar, communication, and spectrum sensing integrated device based on photonic technology, characterized in that: The device includes a continuous wave laser, a first optical power splitter, an amplitude keying signal source, a first 90-degree bridge, a linear frequency modulation signal source, a second 90-degree bridge, a first electrical coupler, a second electrical coupler, a first dual-parallel Mach-Zehnder modulator, a first erbium-doped fiber amplifier, a second optical power splitter, a Mach-Zehnder modulator, a first receiving antenna, a first electrical amplifier, an optical isolator, a nonlinear medium, an optical circulator, a single-tone radio frequency signal source, a third 90-degree bridge, a second dual-parallel Mach-Zehnder modulator, a second erbium-doped fiber amplifier, a first photodetector, a first analog-to-digital converter, a second photodetector, a second electrical amplifier, an electrical power splitter, a transmitting antenna, a second receiving antenna, a third electrical amplifier, an electrical mixer, a second analog-to-digital converter, a third receiving antenna, a fourth electrical amplifier, an envelope detector, and a third analog-to-digital converter. The output port of the continuous wave laser is connected to the input port of the first optical power splitter, one output port of the first optical power splitter is connected to the optical input port of the first dual parallel Mach-Zehnder modulator, the output port of the amplitude keying signal source is connected to the input port of the first 90-degree bridge, and the output port of the linear frequency modulation signal source is connected to the input port of the second 90-degree bridge; the 0-degree output port of the first 90-degree bridge and the 90-degree output port of the second 90-degree bridge are respectively connected to the two input ports of the first electrical coupler, and the 90-degree output port of the first 90-degree bridge and the 0-degree output port of the second 90-degree bridge are respectively connected to the two input ports of the second electrical coupler The output ports of the first electrical coupler and the second electrical coupler are respectively connected to the two RF input ports of the first dual-parallel Mach-Zehnder modulator, the optical output port of the first dual-parallel Mach-Zehnder modulator is connected to the input port of the first erbium-doped fiber amplifier, the output port of the first erbium-doped fiber amplifier is connected to the input port of the second optical power splitter; one output port of the second optical power splitter is connected to the optical input port of the Mach-Zehnder modulator, the output port of the first receiving antenna receiving the signal to be measured is connected to the input port of the first electrical amplifier, the output port of the first electrical amplifier is connected to the RF input port of the Mach-Zehnder modulator, the Mach- The optical output port of the Zehnder modulator is connected to the input port of the optical isolator, the output port of the optical isolator is connected to the input port of the nonlinear medium, the output port of the nonlinear medium is connected to port II of the optical circulator, the output port of the single-tone RF signal source is connected to the input port of the third 90-degree bridge, the output port of the third 90-degree bridge is connected to the RF input port of the second dual-parallel Mach-Zehnder modulator, the other output port of the first optical power splitter is connected to the optical input port of the second dual-parallel Mach-Zehnder modulator, the optical output port of the second dual-parallel Mach-Zehnder modulator is connected to the input port of the second erbium-doped fiber amplifier, and the second The output port of the erbium-doped fiber amplifier is connected to port I of the optical circulator, port III of the optical circulator is connected to the input port of the first photodetector, the output port of the first photodetector is connected to the input port of the first analog-to-digital converter, and the frequency or time-frequency information of the signal to be measured is obtained by processing the frequency information and mapping it into a time-domain pulse; another output port of the second optical power splitter is connected to the input port of the second photodetector, the output port of the second photodetector is connected to the input port of the second electrical amplifier, the output port of the second electrical amplifier is connected to the input port of the electrical power splitter, and one output port of the electrical power splitter is connected to the input port of the transmitting antenna;The echo signal reflected by the detection target is received by the second receiving antenna and injected into the input port of the third electrical amplifier. The output port of the third electrical amplifier is connected to the radio frequency port of the electrical mixer. Another output port of the electrical power splitter is connected to the local oscillator port of the electrical mixer. The intermediate frequency port of the electrical mixer is connected to the input port of the second analog-to-digital converter. The imaging and distance information of the detection target are obtained by processing the de-skewed signal waveform. The communication signal is received by the third receiving antenna and injected into the input port of the fourth electrical amplifier. The output port of the fourth electrical amplifier is connected to the input port of the envelope detector. The output port of the envelope detector is connected to the input port of the third analog-to-digital converter. The communication information can be directly obtained through the collected waveform.

2. The integrated radar, communication, and spectrum sensing device based on photonic technology according to claim 1, characterized in that: The RF amplitude-shifted keying (AMK) signal and the linear frequency modulation (LFM) signal are modulated onto both ends of the optical carrier using suppressed carrier single-sideband (SSB) technology, generating the positive first-order optical sideband of the AMK signal and the negative first-order optical sideband of the LFM signal. The AMK signal bandwidth determines the communication rate, while the LFM signal bandwidth determines the radar resolution and instantaneous bandwidth of spectrum sensing.

3. The integrated radar, communication, and spectrum sensing device based on photonic technology according to claim 1, characterized in that: The negative first-order optical sideband of the linear frequency modulation signal is used as a swept-frequency optical signal. After being suppressed by the carrier single-sideband modulation of the signal to be measured, it interacts with the narrowband optical filter provided by the stimulated Brillouin scattering gain to map the frequency information of the signal to be measured into time-domain pulses. The frequency of the signal to be measured is obtained based on the time when the time-domain pulses appear, realizing the spectrum sensing function.

4. The integrated radar, communication, and spectrum sensing device based on photonic technology according to claim 1, characterized in that: The positive first-order optical sideband of the amplitude keying signal and the negative first-order optical sideband of the linear frequency modulation signal are detected by the photoelectric detector to generate an integrated amplitude keying linear frequency modulation signal for communication and radar detection.

5. The integrated radar, communication, and spectrum sensing device based on photonic technology according to claim 1, characterized in that: The integrated amplitude-keyed linear frequency modulation signal is de-skewed and further processed to achieve ranging and imaging functions, and the communication information is extracted through envelope detection.

6. A radar, communication, and spectrum sensing integrated method using the device of claim 1, characterized in that: The method comprises the following steps: 1) The center frequency of the continuous wave laser output is f c The continuous light wave is divided into two equal parts by the first optical power divider, one part of which is input to the first dual-parallel Mach-Zehnder modulator. The first dual-parallel Mach-Zehnder modulator, the first 90-degree bridge, the second 90-degree bridge, the first electrical coupler and the second electrical coupler are used to suppress the carrier single sideband method to change the center frequency of the RF amplitude keying signal source output to f RF The frequency range of the amplitude keying signal and linear frequency modulation signal source output is f a ~f b The linear frequency modulation signal is modulated to both sides of the optical carrier to generate a center frequency of f c +f RF The positive first-order optical sideband and frequency range of the amplitude-shifted keying signal are f c –f b ~f c –f a The negative first-order optical sideband of the linear frequency modulation signal. 2) The optical signal output by the first dual-parallel Mach-Zehnder modulator is amplified by the first erbium-doped fiber amplifier and then divided into two equal parts by the second optical power splitter. One part of the optical signal is input to the Mach-Zehnder modulator, and then the optical signal is modulated in a suppressed carrier double-sideband manner by the signal to be measured received by the first receiving antenna and amplified by the first electrical amplifier. Since the optical signal output by the second optical power splitter contains a linear frequency modulated optical signal with a frequency of f SUT The signal to be measured is also converted into a swept frequency optical signal corresponding to the signal to be measured after modulation, wherein the negative first-order swept frequency optical sideband frequency band corresponding to the signal to be measured is f c –f b –f SUT ~f c –f a –f SUT ,Then these swept frequency optical signals are injected into the nonlinear medium after passing through the optical isolator. 3) Another part of the optical signal output by the first optical power splitter is input to the second dual parallel Mach-Zehnder modulator, and the optical signal is output by the single-tone RF signal source with a frequency of f x The single-tone signal is modulated in a suppressed carrier single sideband manner to generate a frequency of f c –f x Then, the optical signal output by the second dual-parallel Mach-Zehnder modulator is amplified by the second erbium-doped fiber amplifier, and then injected into the nonlinear medium through the port I and port II of the optical circulator in turn, generating a center frequency of f c –f x –f SBS The stimulated Brillouin scattering gain is used as a narrowband optical filter. 4) The negative first-order swept optical sideband corresponding to the signal to be tested at different frequencies passes through the center frequency f c –f x –f SBS The narrowband optical filter is filtered out at a specific moment to obtain the corresponding optical pulse signal, thereby mapping the frequency information into a time domain pulse. The center frequency of the narrowband optical filter can be adjusted by f x The optical pulse signal passes through ports II and III of the optical circulator and is then injected into the first photodetector, which converts it into an electrical pulse signal. The electrical pulse signal is collected by the first analog-to-digital converter. The frequency information of the signal under test is obtained based on the time of occurrence of the obtained electrical pulse signal. Furthermore, by segmenting and rearranging multiple cycles of the electrical pulse signal, two-dimensional time-frequency information of the signal under test can be obtained. 5) Another part of the optical signal output by the second optical power splitter is injected into the second photodetector to generate a center frequency of f RF +f a / 2+f b Amplitude-keyed linear frequency modulation (AFM) signal with a frequency of 1 / 2 is used for communication and radar detection. After being amplified by a second electrical amplifier, the AFM signal is split into two equal parts by an electrical power divider. One portion of the electrical signal output by the power divider is input to the local oscillator port of the electrical mixer, while the other portion of the signal output by the power divider is radiated into the surrounding space via the transmitting antenna. The echo signal reflected from the target is received by the second receiving antenna, amplified by a third electrical amplifier, and then input to the RF port of the electrical mixer. Mixing by the electrical mixer generates a de-skewed signal, which is then acquired by a second analog-to-digital converter. Processing of the acquired signal waveform yields the target's ranging and imaging results. 6) The amplitude-shifted linear frequency modulation signal received by the third receiving antenna is amplified by the fourth electrical amplifier, and the envelope waveform of the amplitude-shifted linear frequency modulation signal is obtained by the envelope detector. After the envelope waveform is collected by the third analog-to-digital converter, the bit information of the communication transmission can be restored after judgment.

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