Multi-output signal transmitting device, MIMO chaotic lidar and detection and identification device

Abstract

This invention relates to a multi-output signal transmitting device, a MIMO chaotic lidar, and a detection and identification device. The multi-output signal transmitting device of this invention combines chaotic lidar with frequency division multiplexing (FDM) technology and applies it to MIMO lidar technology. It utilizes the large bandwidth and noise-like waveform characteristics of chaotic lidar to improve anti-interference capability and stealth. This invention employs FDM technology, allowing arbitrary selection of frequency bands. A certain degree of overlap is permitted between the channel frequency bands, while maintaining very low cross-correlation. Furthermore, the components in each channel are identical, differing only in the passband setting of the bandpass filter. Therefore, each channel can be configured as a modular device, simplifying operations when increasing or decreasing the number of channels.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, and in particular to a multi-output signal transmitting device, a MIMO chaotic lidar, and a detection and identification device. Background Technology

[0002] With the advancement of radar technology, radar functions have long since evolved from initial target detection, ranging, angle measurement, and velocity measurement to two-dimensional or three-dimensional target imaging. Radar images can help people obtain useful information about the spatial structure and attribute characteristics of targets. Since the 1950s, radar imaging technology has been widely used in many fields such as agricultural and forestry production, environmental protection, disaster reporting, marine monitoring, geographic mapping, resource exploration, non-destructive testing, biomedicine, archaeology, and military applications.

[0003] Patent 201510301702.8 integrates optical ultra-wideband, MIMO radar imaging, and wavelength division multiplexing (WDM) technologies, solving the current problem of the lack of a MIMO radar capable of directly generating multiple, quasi-orthogonal chaotic ultra-wideband signals in the optical domain. In this patent, the transmitted signal, after transmission through optical fiber, is decomposed into chaotic optical signals of different wavelengths by a waveguide grating. During transmission, these signals are converted into microwave signals by a photodetector. However, this technology suffers from low anti-interference capability and poor stealth of the microwave signals. Furthermore, WDM relies on the performance of multi-wavelength semiconductor lasers, which are perturbed by multi-wavelength optical injection combined with optical feedback. The number of usable longitudinal modes is limited, and the wavelengths are fixed, thus limiting the number of MIMO radar channels generated. In WDM, because the waveguide grating characteristics are fixed, the generated chaotic signals and multiple longitudinal modes are also fixed, resulting in fixed MIMO channels that cannot be arbitrarily added or removed, leading to low coordination. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the limitations of the prior art.

[0005] To address the aforementioned technical problems, this invention provides a multi-output signal transmitting device, a MIMO chaotic lidar, and a detection and identification device.

[0006] A multi-output signal transmitting device, comprising:

[0007] A broadband chaotic signal source that generates a continuous chaotic optical signal with large bandwidth, flat spectrum, and suppressed delay characteristics;

[0008] A beam splitter that distributes the broadband chaotic light source according to power, forming multiple branches;

[0009] The optical processing module employs a frequency division multiplexing method and has multiple built-in optical processing units. These multiple optical processing units respectively perform pulse modulation on the broadband chaotic light in the multiple branches to generate pulse orthogonal chaotic signals, which are the transmitted signals.

[0010] A first arbitrary waveform generator is connected to the optical processing module to provide a square wave signal for the pulse modulation of the optical processing module.

[0011] The signal transmitting module includes multiple first collimating lenses, with one first collimating lens in each branch. The first collimating lens is used to collimate and transmit the signal.

[0012] Each branch corresponds to one channel of a multi-output signal transmitting device.

[0013] Preferably, the broadband chaotic signal source includes:

[0014] The main laser outputs a continuous optical signal with a wavelength of 1550nm;

[0015] A first optical coupler splits the laser emitted from the main laser into a first beam and a second beam.

[0016] The slave laser operates freely and is frequency detuned from the master laser by +20 GHz;

[0017] A reflector that injects the first beam into the main laser to generate a time-delay-suppressed broadband chaotic signal;

[0018] A first optical isolator is used to suppress back-reflected optical signals from broadband chaotic optical signals emitted from a laser.

[0019] Preferably, the light processing unit includes:

[0020] A bandpass filter is used to filter out the spectral components corresponding to the chaotic laser signals in each branch of the beam splitter.

[0021] A boost optical amplifier receives the square wave signal and uses the square wave signal to pulse modulate the orthogonal chaotic signal to generate a pulsed orthogonal chaotic signal; wherein, the pulse modulation specifically involves adjusting the duty cycle to control the pulse duration.

[0022] A second optical isolator is used to control interference from back-reflected stray light;

[0023] The first erbium-doped fiber amplifier is used to increase the optical power of the transmitted signal;

[0024] In this process, after passing through the bandpass filter, the chaotic laser signals in each branch correspond to different spectral component ranges, thus achieving frequency division multiplexing.

[0025] A MIMO chaotic lidar includes:

[0026] The multi-output signal transmitting device and detection device described above, wherein the detection device includes:

[0027] The receiving module receives the echo signal reflected by the test object from the transmitted signal and converts the echo signal into a radio frequency signal;

[0028] The ranging and imaging module receives a reference signal derived from the transmitted signal and the echo signal, calculates the target distance by performing cross-correlation calculations using the time delay between the reference signal and the echo signal, analyzes and images based on the intensity information of the echo signal and the calculated distance information, and outputs a digital signal carrying the target information.

[0029] Preferably, the receiving module includes:

[0030] A receiving antenna, which is a second collimating lens, is used to receive the echo signal reflected by the test object from the transmitted signal;

[0031] A second erbium-doped fiber amplifier amplifies the power of the echo signal;

[0032] A first photodetector converts the echo signal into a radio frequency signal.

[0033] Preferably, the ranging imaging module includes:

[0034] An optical fiber coupler is disposed between the optical processing module and the signal transmitting module, and is used to separate a low-power signal from the transmitted signal as a reference signal;

[0035] A second photodetector is used to convert the reference signal into a radio frequency signal;

[0036] The processing module receives the echo signal and the reference signal, outputs the time delay Δτ between the echo signal and the reference signal, performs cross-correlation calculation on the echo signal and the reference signal, and obtains the target distance d as d = cΔτ / 2, where c is the speed of light in vacuum.

[0037] A detection and identification device, comprising:

[0038] The MIMO chaotic lidar and reservoir system described above, wherein the reservoir system includes:

[0039] The target input module receives the digital signal output by the ranging imaging module and extracts the feature values ​​of the target object from the digital signal.

[0040] The drive response module provides the optical carrier signal of the reservoir system and modulates the feature value information of the target object onto the optical carrier to obtain an optical signal carrying the feature value of the target object; and performs nonlinear mapping processing on the system under the injection of the optical signal through a feedback loop.

[0041] The recognition output module converts the processed optical signal into a digital signal, obtains the response state through the digital signal, samples virtual nodes, and multiplies the virtual nodes with the corresponding output weights to obtain the target recognition output result.

[0042] Preferably, the target input module includes:

[0043] A first digital signal processor processes a digital signal carrying target information and extracts the feature values ​​of the target object.

[0044] A second arbitrary waveform generator generates a pre-processed input signal for the reservoir system.

[0045] Preferably, the drive response module includes:

[0046] A driving laser that outputs a continuous optical signal with a wavelength of 1550nm;

[0047] An intensity modulator receives the input signal from the pre-processed reservoir system at its high-speed radio frequency input terminal and outputs an optical signal carrying the characteristic value of the target object.

[0048] The optical signal is injected into the optical laser and passes through the optical feedback loop to generate a rich dynamic response, thereby performing nonlinear mapping processing on the input signal.

[0049] Preferably, the identification output module includes:

[0050] The third photodetector converts the optical signal into an electrical signal;

[0051] An analog-to-digital converter (ADC) that converts electrical signals into digital signals;

[0052] The second signal processor reads the output of the response laser to obtain the response state and samples virtual nodes. The virtual nodes are multiplied by the corresponding output weights to obtain the target recognition output result.

[0053] The technical solution of the present invention has the following advantages compared with the prior art:

[0054] 1. This invention combines chaotic lidar with frequency division multiplexing (FDM) technology and applies it to MIMO radar technology. Leveraging the large bandwidth and noise-like waveform characteristics of chaotic lidar, it enhances anti-interference capabilities and concealment. The FDM technology allows for arbitrary selection of frequency bands, permitting some overlap between channels while maintaining very low cross-correlation. Increasing the number of channels effectively improves detection efficiency.

[0055] 2. The components in each channel of this invention are identical, except for the passband setting of the bandpass filter. Therefore, each channel can be configured as a modular device, simplifying the operation when the number of channels needs to be increased or decreased.

[0056] 3. This invention uses pulse modulation technology, which can reduce energy consumption. The duration of the transmitted pulse can be adjusted by adjusting the duty cycle. Because cross-correlation technology is used for ranging, different pulse durations can be set according to the range of the required ranging to save power consumption.

[0057] 4. This invention utilizes the high-speed, high-capacity computing of photonic neural networks to rapidly and autonomously process large amounts of radar data: After the echo signal of the MIMO chaotic lidar is acquired and preprocessed, feature values ​​are extracted. The resulting feature value sequence is then masked and injected into the delay base reserve pool for training, ultimately achieving target recognition and classification, which can greatly reduce training time and cost. Attached Figure Description

[0058] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0059] Figure 1 This is a simplified diagram of the multi-output signal transmitting device of the present invention.

[0060] Figure 2 This is a schematic diagram of the multi-output signal transmitting device of the present invention.

[0061] Figure 3 This is a simplified diagram of the MIMO chaotic lidar of the present invention.

[0062] Figure 4 This is a schematic diagram of the MIMO chaotic lidar of the present invention.

[0063] Figure 5This is a simplified diagram of the detection and identification device of the present invention.

[0064] Figure 6 This is a schematic diagram of the detection and identification device of the present invention.

[0065] Explanation of reference numerals in the accompanying drawings: 1. Broadband chaotic signal source; 11. Main laser; 12. First optical coupler; 13. Mirror; 14. Slave laser; 15. First optical isolator; 2. Beam splitter; 3. Optical processing module; 31. Optical processing unit; 301. Bandpass filter; 302. Boost optical amplifier; 303. Second optical isolator; 304. First erbium-doped fiber amplifier; 4. First arbitrary waveform generator; 5. Signal transmitting module; 51. First collimating lens; 6. Receiving module; 61. Receiving antenna ; 62. Second erbium-doped fiber amplifier; 63. First photodetector; 7. Ranging and imaging module; 71. Fiber coupler; 72. Second photodetector; 73. Processing module; 8. Target input module; 81. First digital signal processor; 82. Second arbitrary waveform generator; 9. Drive response module; 91. Drive laser; 92. Intensity modulator; 93. Response laser; 10. Identification output module; 101. Third photodetector; 102. Analog-to-digital converter; 103. Second signal processor. Detailed Implementation

[0066] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0067] like Figure 1-2 As shown, this invention discloses a multi-output signal transmitting device, comprising:

[0068] Broadband chaotic signal source 1 generates a continuous chaotic optical signal with large bandwidth, flat spectrum, and suppressed delay characteristics;

[0069] The beam splitter 2 distributes the broadband chaotic light source according to power to form multiple branches; each branch corresponds to a channel of the multi-output signal transmitting device.

[0070] The optical processing module 3 employs a frequency division multiplexing method and contains multiple optical processing units 31. Each of the multiple optical processing units 31 performs pulse modulation on the broadband chaotic light in the multiple branches to generate pulsed orthogonal chaotic signals, which are transmitted signals. Specifically, the pulse modulation involves adjusting the duty cycle to control the pulse duration.

[0071] A first arbitrary waveform generator 4 is connected to the optical processing module 3 and provides a square wave signal for the pulse modulation of the optical processing module 3.

[0072] The signal transmitting module 5 includes multiple first collimating lenses 51, with one first collimating lens 51 disposed in each branch. These first collimating lenses 51 are used to collimate the transmitted signal, which helps to reduce the divergence angle and increase the strength of the received signal. In a specific embodiment, the first collimating lens 51 is a collimating lens coated with a high-transmittance film, effectively reducing the power loss of the chaotic light signal passing through, thereby improving the detection probability.

[0073] In an optional embodiment, the broadband chaotic signal source 1 includes: a master laser 11, a first optical coupler 12, a reflector 13, a slave laser 14, and a first optical isolator 15. The master laser 11 outputs a continuous optical signal with a wavelength of 1550 nm. The slave laser 14 operates freely, and its frequency detuning from that of the master laser 11 is +20 GHz. The first optical coupler 12 splits the laser emitted from the master laser 11 into a first beam and a second beam. The reflector 13 injects the first beam into the master laser 11, generating a time-delay-suppressed broadband chaotic signal. The first optical isolator 15 is used to suppress the back-reflected optical signal from the slave laser 14 from being injected into the broadband chaotic light source system and affecting the signal source, thereby ensuring the stability and reliability of the broadband chaotic light source structure.

[0074] In an optional embodiment, the optical processing unit 31 includes a bandpass filter 301 and a boost optical amplifier 302. The bandpass filter 301 is used to filter out the spectral components corresponding to the chaotic laser signals in each branch of the beam splitter 2. The passbands of the bandpass filters 301 in each branch of the beam splitter 2 are different. This arrangement allows the range of spectral components corresponding to the chaotic laser signals output by each optical processing unit 31 to be different, resulting in orthogonal chaotic signals, thereby avoiding interference caused by cross-correlation between the branches. In an optional embodiment, the selection of the passband interval of the bandpass filter 301 follows the principle that the lowest passband frequency of adjacent filters increases sequentially, and the passband frequency of the previous filter overlaps slightly with the passband frequency of the next filter. Preferably, the selection of the passband interval of the bandpass filter 301 follows the principle that the lowest passband frequency increases sequentially and the filter bandwidth is the same, and the difference between the lowest passband frequencies of adjacent filters is a fixed value Δf. The boost optical amplifier 302 receives the square wave signal and uses it to modulate the orthogonal chaotic signal to generate a pulsed orthogonal chaotic signal, which is the transmitted signal. The boost optical amplifier 302 also increases the optical power of the split orthogonal chaotic signal, thus preventing the orthogonal chaotic signal from being overwhelmed by noise.

[0075] In one specific embodiment, the optical processing unit 31 further includes a second optical isolator 303 and a first erbium-doped fiber amplifier 304. The second optical isolator 303 is used to control interference from back-reflected stray light. The erbium-doped fiber amplifier is used to increase the power of the transmitted signal optical light, thus reducing the impact of losses during optical signal transmission and reflection in the air.

[0076] like Figure 3-4 As shown, the present invention also discloses a MIMO chaotic lidar, comprising a multi-output signal transmitting device and a detection device as described above, wherein the detection device includes:

[0077] Receiver module 6 receives the echo signal reflected by the test object from the transmitted signal and converts the echo signal into a radio frequency signal;

[0078] The ranging and imaging module 7 receives a reference signal derived from the transmitted signal and the echo signal, calculates the target distance by performing cross-correlation calculations using the delay time between the reference signal and the echo signal, analyzes and images based on the intensity information of the echo signal and the calculated distance information, and outputs a digital signal carrying the target information.

[0079] In an optional embodiment, the receiving module 6 includes a receiving antenna 61, a second erbium-doped fiber amplifier 62, and a first photodetector 63. The receiving antenna 61 is a second collimating lens used to receive the echo signal reflected from the test object by the transmitted signal. This configuration helps to reduce the divergence angle and increase the strength of the received signal. In a specific embodiment, the first collimating lens 61 is a collimating lens coated with a high-transmittance film, effectively reducing the power loss of the transmitted chaotic light signal to improve the detection probability. The second erbium-doped fiber amplifier 62 amplifies the power of the echo signal. The first photodetector 63 converts the echo signal into a radio frequency signal.

[0080] In an optional embodiment, the ranging imaging module 7 includes: an optical fiber coupler 71, a second photodetector 72, and a processing module 73. The optical fiber coupler 71 is disposed between the optical processing module 73 and the signal transmitting module 5, and is used to separate a low-power signal from the transmitted signal as a reference signal. In a specific embodiment, the power division ratio of the optical fiber coupler 71 is set to 1:9. The second photodetector 72 is used to convert the reference signal into a radio frequency signal. The processing module 73 receives the echo signal and the reference signal, outputs the time delay Δτ between the echo signal and the reference signal, performs cross-correlation calculation on the echo signal and the reference signal, and obtains the target distance d as d = cΔτ / 2, where c is the speed of light in vacuum.

[0081] like Figure 5-6 As shown, the present invention also discloses a detection and identification device, including the MIMO chaotic lidar and the reservoir system described above, wherein the reservoir system includes:

[0082] The target input module 8 receives the digital signal output by the ranging imaging module 7 and extracts the feature value of the target object from the digital signal.

[0083] The drive response module 9 provides the optical carrier signal of the reservoir system and modulates the feature value information of the target object onto the optical carrier to obtain an optical signal carrying the feature value of the target object; and performs nonlinear mapping processing on the system under the injection of the optical signal through a feedback loop.

[0084] The recognition output module 10 converts the processed optical signal into a digital signal, obtains the response state through the digital signal, samples and obtains virtual nodes, and multiplies the virtual nodes by the corresponding output weights to obtain the target recognition output result.

[0085] In an optional embodiment, the target input module 8 includes: a first digital signal processor 81 and a second arbitrary waveform generator 82. The first digital signal processor 81 processes the digital signal carrying target information and extracts the feature values ​​of the target object. The second arbitrary waveform generator 82 generates a pre-processed reservoir system input signal.

[0086] In an optional embodiment, the drive response module 9 includes a drive laser 91, an intensity modulator 92, and a response laser 93. The drive laser 91 outputs a continuous optical signal with a wavelength of 1550 nm. The high-speed radio frequency input terminal of the intensity modulator 92 receives the input signal from the pre-processed reservoir system and outputs an optical signal carrying the target object's characteristic values. The response laser 93 has an external cavity feedback loop. After the optical signal is injected into the response laser 93 and passes through the optical feedback loop, it generates a rich dynamic response, thereby performing nonlinear mapping processing on the input signal.

[0087] In an optional embodiment, the identification output module 10 includes: a third photodetector 101, an analog-to-digital converter 102, and a second signal processor 103. The third photodetector 101 converts optical signals into electrical signals. The analog-to-digital converter 102 converts electrical signals into digital signals. The second digital signal processor reads the output of the response laser 93 to obtain the response state and samples it to obtain virtual nodes. The virtual nodes are multiplied by their corresponding output weights to obtain the target identification output result.

[0088] In an optional embodiment, the center wavelengths of the master laser 11, the slave laser 14, the driver laser 91, and the response laser 93 are all around 1550 nm.

[0089] In an optional embodiment, the wavelength of the main laser 11 is matched with the operating band of the boost optical amplifier 302 to obtain optimal gain.

[0090] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A multi-output signal transmitting apparatus, characterized by comprising: include: A broadband chaotic signal source that generates a continuous chaotic optical signal with large bandwidth, flat spectrum, and suppressed delay characteristics; A beam splitter that distributes the chaotic optical signal according to power to form multiple branches; The optical processing module employs a frequency division multiplexing method and has multiple built-in optical processing units. These multiple optical processing units respectively perform pulse modulation on the broadband chaotic light in the multiple branches to generate pulse orthogonal chaotic signals, which are the transmitted signals. A first arbitrary waveform generator is connected to the optical processing module to provide a square wave signal for the pulse modulation of the optical processing module. The signal transmitting module includes multiple first collimating lenses, with one first collimating lens in each branch. The first collimating lens is used to collimate and transmit the signal. Each branch corresponds to one channel of a multi-output signal transmitting device.

2. The multiple output signal launching device of claim 1, wherein, The broadband chaotic signal source includes: The main laser outputs a continuous optical signal with a wavelength of 1550nm; A first optical coupler splits the laser emitted from the main laser into a first beam and a second beam. The slave laser operates freely and is frequency detuned from the master laser by +20 GHz; A reflector that injects the first beam into the main laser to generate a time-delay-suppressed broadband chaotic signal; A first optical isolator is used to suppress back-reflected optical signals from broadband chaotic optical signals emitted from a laser.

3. The multiple output signal launching device of claim 1, wherein, The light processing unit includes: A bandpass filter is used to filter out the spectral components corresponding to the chaotic laser signals in each branch of the beam splitter. A boost optical amplifier receives the square wave signal and uses the square wave signal to pulse modulate the orthogonal chaotic signal to generate a pulsed orthogonal chaotic signal; wherein, the pulse modulation specifically involves adjusting the duty cycle to control the pulse duration. A second optical isolator is used to control interference from back-reflected stray light; The first erbium-doped fiber amplifier is used to increase the optical power of the transmitted signal; In this process, after passing through the bandpass filter, the chaotic laser signals in each branch correspond to different spectral component ranges, thus achieving frequency division multiplexing.

4. A MIMO chaotic lidar, characterized in that, include: The multi-output signal transmitting device and detection device as described in any one of claims 1-3, wherein the detection device comprises: The receiving module receives the echo signal reflected by the test object from the transmitted signal and converts the echo signal into a radio frequency signal; The ranging and imaging module receives a reference signal derived from the transmitted signal and the echo signal, calculates the target distance by performing cross-correlation calculations using the time delay between the reference signal and the echo signal, analyzes and images based on the intensity information of the echo signal and the calculated distance information, and outputs a digital signal carrying the target information.

5. The MIMO chaotic lidar of claim 4, wherein, The receiving module includes: A receiving antenna, which is a second collimating lens, is used to receive the echo signal reflected by the test object from the transmitted signal; A second erbium-doped fiber amplifier amplifies the power of the echo signal; A first photodetector converts the echo signal into a radio frequency signal.

6. The MIMO chaotic lidar according to claim 4, characterized in that, The ranging imaging module includes: An optical fiber coupler is disposed between the optical processing module and the signal transmitting module, and is used to separate a low-power signal from the transmitted signal as a reference signal; A second photodetector is used to convert the reference signal into a radio frequency signal; The processing module receives the echo signal and the reference signal, and outputs the time delay D between the echo signal and the reference signal. t The target distance d is obtained by performing cross-correlation calculation on the echo signal and the reference signal, which is d = cD. t / 2, where c is the speed of light in a vacuum.

7. A detection identification device, characterized in that include: The MIMO chaotic lidar and reservoir system according to any one of claims 4-6, wherein the reservoir system comprises: The target input module receives the digital signal output by the ranging imaging module and extracts the feature values ​​of the target object from the digital signal. The drive response module provides the optical carrier signal of the reservoir system and modulates the feature value information of the target object onto the optical carrier to obtain an optical signal carrying the feature value of the target object; and performs nonlinear mapping processing on the system under the injection of the optical signal through a feedback loop. The recognition output module converts the processed optical signal into a digital signal, obtains the response state through the digital signal, samples virtual nodes, and multiplies the virtual nodes with the corresponding output weights to obtain the target recognition output result.

8. The probe identification device of claim 7, wherein, The target input module includes: A first digital signal processor processes a digital signal carrying target information and extracts the feature values ​​of the target object. A second arbitrary waveform generator generates a pre-processed input signal for the reservoir system.

9. The probe identification device of claim 8, wherein, The drive response module includes: A driving laser that outputs a continuous optical signal with a wavelength of 1550nm; An intensity modulator receives the input signal from the pre-processed reservoir system at its high-speed radio frequency input terminal and outputs an optical signal carrying the characteristic value of the target object. The optical signal is injected into the optical laser and passes through the optical feedback loop to generate a rich dynamic response, thereby performing nonlinear mapping processing on the input signal.

10. The probe identification device of claim 7, wherein, The identification output module includes: The third photodetector converts the optical signal into an electrical signal; An analog-to-digital converter (ADC) that converts electrical signals into digital signals; The second signal processor reads the output of the response laser to obtain the response state and samples virtual nodes. The virtual nodes are multiplied by the corresponding output weights to obtain the target recognition output result.

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