A method and system for implementing a wavelength conversion based solid state radar

Abstract

The application discloses a wavelength conversion-based solid-state radar implementation method and system, which comprises the following steps: modulating and encoding a first-wavelength laser light source to generate a local signal, and splitting the local signal to generate multiple laser beams; wavelength converting the multiple laser beams to obtain second-wavelength detection laser beams, and obtaining echo signals of different wavelengths according to detection results of the detection laser beams; calibrating the echo signals of different wavelengths to obtain measured echo signals; and obtaining measured distances under each channel according to comparison and analysis results of the measured echo signals and the local signal. The application can improve the maximum measurement distance of the current solid-state laser radar, and reduce the difficulty of system integration and the requirement for a large-area detector.

Description

Technical Field

[0001] This invention relates to the field of laser three-dimensional imaging radar technology, and in particular to a method and system for implementing solid-state radar based on wavelength conversion. Background Technology

[0002] With the development of autonomous driving and intelligent robotics, the requirements for imaging and ranging lidar will gradually increase. Improving the integration stability and imaging quality of lidar will be a major problem that practitioners need to solve. In pursuit of lidar stability, mechanical scanning lidar, semi-solid-state micro-mirror scanning lidar, and all-solid-state phased array scanning lidar and all-solid-state flash lidar have emerged successively. Because all-solid-state flash lidar acquires single-frame pixel data simultaneously, it can produce distortion-free imaging compared to scanning imaging lidar, making it an ideal lidar imaging solution.

[0003] However, due to technological limitations, flash radar with a surface light source emission and surface array reception still faces two obstacles. At the light source emission end: signal crosstalk occurs between the point light sources in the integrated chip light source due to diffraction sidelobes; the surface array emission method significantly weakens the power distributed among individual points, severely limiting the radar's detection range; furthermore, flash radar has the smallest field of view among all types of radar. At the focal plane receiver end: the number of point clouds in a single frame image is limited by the area of ​​the current APD detector array. Using a large-area APD detector would greatly increase the radar cost, and large-area detectors are currently subject to strict international regulations.

[0004] Therefore, how to adopt new technological concepts and integration methods to increase the detection range of laser flash radar, expand the field of view, suppress signal crosstalk, and remove the limitations of large-area APD detectors has become a key issue for future laser flash radar. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] To address this, this invention proposes a method for implementing solid-state radar based on wavelength conversion, enabling simultaneous acquisition of multi-line measurements. Simultaneously, this invention also extends the detection range of flash radar by eliminating crosstalk between channels and reducing the requirements for echo detectors through independent channel distribution and reception.

[0007] Another objective of this invention is to propose a system for implementing a solid-state radar based on wavelength conversion.

[0008] To achieve the above objectives, the present invention proposes a method for implementing a solid-state radar based on wavelength conversion, comprising:

[0009] The laser source of the first wavelength is modulated and encoded to generate a local oscillator signal, and the local oscillator signal is split to generate multiple laser beams;

[0010] The multi-channel laser is wavelength-converted to obtain a second wavelength detection laser, and echo signals of different wavelengths are obtained based on the detection results of the detection laser.

[0011] The measured echo signals are obtained by calibrating the echo signals of different wavelengths.

[0012] The measured distance for each channel is obtained based on the comparative analysis results of the measured echo signal and the local oscillator signal.

[0013] In addition, the implementation method of the wavelength conversion-based solid-state radar according to the above embodiments of the present invention may also have the following additional technical features:

[0014] Furthermore, in one embodiment of the present invention, the step of wavelength conversion of the multiple lasers to obtain a second wavelength detection laser includes:

[0015] The multiple channels of the wavelength converter are used to convert the injected first wavelength multi-channel laser into a second wavelength probe laser.

[0016] Furthermore, in one embodiment of the present invention, obtaining echo signals of different wavelengths based on the detection result of the probe laser includes:

[0017] A second-wavelength detection laser is emitted into the detection area using a signal transmitter at a preset emission angle to detect obstacles and obtain the detection results.

[0018] Echo signals of different wavelengths are generated based on the detection results of the obstacles.

[0019] Furthermore, in one embodiment of the present invention, obtaining the measured echo signal by calibrating the echo signals of different wavelengths includes:

[0020] The echo signals of different wavelengths are calibrated by a wavelength identifier, so that the echo signals of different wavelengths are separated from each other at different angles to obtain the separated and measured echo signals.

[0021] Furthermore, in one embodiment of the present invention, obtaining the measured distance value of each channel based on the comparative analysis results of the measured echo signal and the local oscillator signal includes:

[0022] The local oscillator signal and the measured echo signal are acquired using a signal processor.

[0023] By comparing the signal delays of the local oscillator signal and the measured echo signal, the distances measured for each channel are calculated based on the delay comparison results.

[0024] The final measured distance value is obtained by compensating and correcting the distance measured by each path based on the initial optical path generated by the optical path.

[0025] To achieve the above objectives, another aspect of the present invention proposes a system for implementing a wavelength-converting solid-state radar, comprising: an initial light source, a signal modulator, an amplifier, a beam splitter, a wavelength converter, a signal transmitter, a wavelength identifier, a detector, and a data processor; wherein,

[0026] The initial light source is used to generate a continuous laser light source of the first wavelength;

[0027] The signal modulator is used to modulate the laser source into a local oscillator signal;

[0028] The amplifier is used to amplify the power of the local oscillator signal;

[0029] The beam splitter is used to divide the amplified local oscillator signal into multiple local oscillator signals;

[0030] The wavelength converter is used to convert the multi-channel local oscillator signal of the first wavelength into the multi-channel local oscillator signal of the second wavelength;

[0031] The signal transmitter is used to transmit a multi-channel local oscillator signal of the second wavelength to the detection area at a preset transmission angle to generate echo signals of different wavelengths.

[0032] The wavelength identifier is used to identify echo signals of different wavelengths;

[0033] The detector is used to convert the identified echo signal into an electrical signal;

[0034] The data processor is used to convert the electrical signal into a measured distance value and obtain point cloud coordinates based on the initial azimuth angles of each path.

[0035] The implementation method and system of solid-state radar based on wavelength conversion in this invention achieves simultaneous transmission of multiple channels through initial signal modulation and amplification, signal beam splitting, and wavelength conversion. Each channel's local oscillator signal generates an echo signal upon encountering an obstacle. The echo signals of different wavelengths are identified, calibrated, and coupled to independent photoelectric detection units to generate photoelectric signals. The photoelectric signals from each channel are analyzed by a data processor to obtain the detection results for each channel. This method can improve the maximum measurement distance of current solid-state lidar and reduce the difficulty of system integration and the requirements for large-area array detectors.

[0036] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0038] Figure 1 A flowchart illustrating the implementation method of a wavelength-conversion-based solid-state radar provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram illustrating the implementation method of a wavelength conversion-based solid-state radar provided in an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of a detection signal transmission system provided in an embodiment of the present invention;

[0041] Figure 4 This is a specific integrated schematic diagram of the detection signal transmission system provided in an embodiment of the present invention;

[0042] Figure 5 This is a specific integrated schematic diagram of an echo signal receiving system provided in an embodiment of the present invention;

[0043] Figure 6 This is a structural diagram of a solid-state radar implementation system based on wavelength conversion provided in an embodiment of the present invention. Detailed Implementation

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0046] The implementation method and system of a wavelength conversion-based solid-state radar according to embodiments of the present invention are described below with reference to the accompanying drawings.

[0047] Figure 1 This is a flowchart of the implementation method of a wavelength conversion-based solid-state radar according to an embodiment of the present invention.

[0048] like Figure 1 As shown, the method includes, but is not limited to, the following steps:

[0049] S1, modulate and encode the laser source of the first wavelength to generate the local oscillator signal, and split the local oscillator signal to generate multiple laser beams;

[0050] S2, perform wavelength conversion on the multi-channel laser to obtain the second wavelength detection laser, and obtain echo signals of different wavelengths based on the detection results of the detection laser;

[0051] S3, the measured echo signal is obtained by calibrating the echo signals of different wavelengths;

[0052] S4. The measured distance for each channel is obtained based on the comparative analysis results of the measured echo signal and the local oscillator signal.

[0053] Specifically, such as Figure 2 As shown in the diagram, this invention provides a schematic diagram of an implementation method for a solid-state radar based on wavelength conversion, which specifically includes the following steps:

[0054] S101. A single-wavelength λ0 continuous laser is used as the initial light source;

[0055] S102. The initial light source is modulated and encoded using a modulator to generate a local oscillator signal;

[0056] S103. The modulated signal can be amplified;

[0057] S104. Split the amplified signal to generate n laser beams;

[0058] S105. The wavelength of the multi-channel laser injection is converted, and the wavelengths of the n-channel signals are changed from the initial λ0 to λ1, λ2, λ3, ... λ n ;

[0059] S106. Multiple probe beams of different wavelengths are emitted to the detection area through the transmitter, and an echo signal is generated when they encounter the target object.

[0060] S107. The echo signals are distinguished by a wavelength identifier, and the echo signals at different wavelengths are coupled to the corresponding detectors.

[0061] S108. The measured echo signal is compared and analyzed with the initial local oscillator signal using a signal processor to obtain the distance r measured in each channel. i .

[0062] Furthermore, wavelength conversion is achieved using a wavelength converter fabricated from novel laser materials. The wavelength converter can be structured as a fiber array or a waveguide array. The i-th channel of the converter converts the injected laser light with wavelength λ0 into light with wavelength λ. i The detection laser is coupled to the transmitter. This novel material is a laser material based on phonon-assisted transitions, achieving signal conversion to a specific wavelength through component doping control and feedback design. For a wavelength of λ... i The laser channel, at which point the laser conversion material possesses a laser-to-silicon laser (λ) wavelength. i The passband centered on λ0, and by absorbing the original signal λ0, the output λ i .

[0063] Furthermore, the wavelength identifier can be a dispersive element or a bandpass element: the dispersive element separates echo signals of different wavelengths at different angles; while the bandpass element allows echo signals of a specified wavelength window to pass through; ultimately, the echo signals of different wavelengths are separated and coupled to the corresponding detection unit. The dispersive element can be a grating or prism, and the bandpass element can be a bandpass filter, a thin film, or a photonic bandgap fiber with bandpass functionality.

[0064] Furthermore, the wavelength is λ i The detection laser has a fixed emission angle [α] at the transmitter. i ,β i Different emission angles can be set using a clustered fiber optic transmitter or an integrated optical waveguide transmitter; the transmitter sends guided probe lasers toward the detection area; the probe lasers generate echo signals of different wavelengths when they encounter obstacles.

[0065] Furthermore, the modulator generates an initial local oscillator signal and transmits this initial signal to the signal processor for storage; the echo signal is transmitted to the processor; the time delay or frequency delay of the two types of signals is compared and analyzed, and finally the distance measured by each channel is calculated; based on the initial optical path generated by the system's own optical path, the distance measured by each channel is physically calibrated and compensated to obtain an accurate distance value r. i .

[0066] Preferably, in step S101 above, the single-wavelength continuous laser used in this invention can be a conventional semiconductor laser, as long as it has stable output power.

[0067] Preferably, in step S102 above, the modulated local oscillator signal is an intensity-modulated pulse signal or a frequency-modulated continuous wave signal.

[0068] Preferably, in step S103 above, in order to extend the maximum measurable distance of the radar, the laser needs to be amplified in power. The amplifier can be a fiber optic amplifier or a semiconductor optical amplifier.

[0069] Preferably, in step S104 above, the amplified local oscillator signal is split into beams, and the beam splitter is an optical fiber beam splitter or a waveguide device.

[0070] Preferably, in step S105 above, the split local oscillator laser beams are injected into the wavelength conversion material. The wavelength conversion material is a laser material based on phonon-assisted transitions, and signal conversion to a specific wavelength is achieved through component doping control and feedback design. For a wavelength of λ... i The laser channel, at which point the laser conversion material possesses a laser-to-silicon laser (λ) wavelength. i The passband centered on λ0, and by absorbing the original signal λ0, the output λ i This wavelength conversion material can be fabricated into fiber optic structures or adapted to three-dimensional waveguide devices and beam splitters in S104. For example, when S104 is based on a fiber optic beam splitter to achieve beam splitting, the wavelength conversion material can be fabricated into a fiber optic structure and directly fused to the output fiber of the beam splitter.

[0071] Preferably, in step S106 above, the emission of laser signals from different channels is achieved by a cluster emitter. Figure 3 A schematic diagram of a laser emitter provided in an embodiment of the present invention, as shown below. Figure 3 As shown, multiple optical fibers are bundled and constrained inside the transmitter. The optical fiber output heads are distributed on the inner wall of the transmitter at a set azimuth angle through a fixing component. A collimating lens array is distributed on the outer wall of the transmitter to collimate the beams emitted by each optical fiber. Figure 3 The left image is a cross-sectional view of the transmitter; Figure 3 The middle figure shows the wavelength λ. i The fiber optic channel and the corresponding transmission angle [α] i ,β i Furthermore, it demonstrates the field of view angle φ that the system can detect; Figure 3 The image on the right is a 3D model diagram.

[0072] Preferably, in step S107 above, the reception and classification of echo signals can be implemented in various ways. Figure 4 and Figure 5 This is a schematic diagram of two receivers provided in embodiments of the present invention. Figure 4 As shown, the echo signal is focused into a diffraction grating by a large-aperture focusing mirror. Echo beams of different wavelengths, after passing through the grating, will produce different diffraction angles for separation. These angles are then monitored by a photodetector. Figure 5As shown, the echo signal is focused onto the main fiber end of the fiber optic beam splitter by a large-aperture focusing lens. Bandpass filters (BP) are integrated on each branch fiber to separate the echo signal. This separation can be achieved by directly etching a grating onto the fiber or depositing a filter film on the fiber end face, ensuring that only λ-pass fibers in the i-th fiber are allowed to pass through. i The echo signal passes through. The detector can be a typical photodetector: APD avalanche diode, SPAD single-photon avalanche diode, and SiPM silicon photomultiplier tube; or it can be a more mature and inexpensive thermal detector.

[0073] Preferably, in step S108 above, the measured echo signal is compared and analyzed with the initial local oscillator signal by a signal processor to obtain the distance r measured in each channel. i The initial local oscillator signal can be an intensity-modulated pulse signal or a frequency-modulated continuous wave signal. The corresponding signal analysis object is the time delay between the local oscillator signal and the echo signal pulses, or the frequency shift between the local oscillator signal and the echo signal. Based on the initial optical path generated by the system's own optical path, the distances measured in each path are compensated and corrected to obtain an accurate distance value r. i .

[0074] According to the implementation method of solid-state radar based on wavelength conversion according to embodiments of the present invention, a single light source and a single modulator are used to achieve simultaneous transmission of multi-line radar through wavelength conversion distribution. Each laser signal is transmitted through an independent optical fiber channel, greatly increasing the upper limit of single-channel laser power, thereby solving the current problem of long-range detection in solid-state radar. At the signal transmitting end, a clustered transmitter is used to achieve omnidirectional coverage. In addition, at the detection end, a wavelength identifier is used to separate the echo signals of each channel, thereby enabling the use of separate individual photodetectors to independently measure a single channel, effectively reducing the pixel requirements of large-area array detectors at the detection end.

[0075] To achieve the above embodiments, such as Figure 6 As shown, this embodiment also provides a system 10 for implementing a solid-state radar based on wavelength conversion. This system 10 includes: an initial light source 100, a signal modulator 200, an amplifier 300, a beam splitter 400, a wavelength converter 500, a signal transmitter 600, a wavelength identifier 700, a detector 800, and a data processor 900; wherein,

[0076] The initial light source 100 is used to generate a continuous laser light source of the first wavelength;

[0077] The signal modulator 200 is used to modulate the laser source into a local oscillator signal;

[0078] The amplifier 300 is used to amplify the power of the local oscillator signal;

[0079] The beam splitter 400 is used to divide the amplified local oscillator signal into multiple local oscillator signals;

[0080] The wavelength converter 500 is used to convert the multi-channel local oscillator signal of the first wavelength into the multi-channel local oscillator signal of the second wavelength.

[0081] The signal transmitter 600 is used to transmit a multi-channel local oscillator signal of the second wavelength to the detection area at a preset transmission angle to generate echo signals of different wavelengths.

[0082] The wavelength identifier 700 is used to identify echo signals of different wavelengths;

[0083] The detector 800 is used to convert the identified echo signal into an electrical signal;

[0084] The data processor 900 is used to convert the electrical signal into a measured distance value and obtain point cloud coordinates based on the initial azimuth angles of each path.

[0085] Furthermore, the aforementioned wavelength converter 500 includes one of an optical fiber array and a waveguide array.

[0086] Furthermore, the wavelength identifier 700 mentioned above includes one of a dispersive element and a bandpass element; wherein the dispersive element includes one of a grating and a prism, and the bandpass element includes one of a bandpass filter, a thin film, and a photonic bandgap fiber.

[0087] Furthermore, the transmission angle is set using a clustered fiber optic transmitter or an integrated optical waveguide transmitter.

[0088] Furthermore, the aforementioned detector 800 is also used to couple the identified echo signals to eliminate crosstalk between different channels.

[0089] The solid-state radar system based on wavelength conversion according to embodiments of the present invention achieves simultaneous transmission of multiple radar lines using a single light source and a single modulator, distributed through wavelength conversion. Each laser signal is transmitted through an independent fiber optic channel, significantly increasing the upper limit of single-channel laser power, thereby solving the current challenge of long-range detection in solid-state radar. At the signal transmitting end, a clustered transmitter is used to achieve omnidirectional coverage. Furthermore, at the detection end, a wavelength identifier separates the echo signals from each channel, enabling independent measurement of a single channel using separate individual photodetectors, effectively reducing the pixel count requirement of large-area detectors at the detection end.

[0090] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0091] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for implementing a solid-state radar based on wavelength conversion, characterized in that, Includes the following steps: The laser source of the first wavelength is modulated and encoded to generate a local oscillator signal, and the local oscillator signal is split to generate multiple laser beams; The wavelength converter uses multiple channels to convert the wavelengths of multiple lasers from a first wavelength to their respective second wavelengths in order to obtain multiple probe lasers. The wavelength converter is an optical fiber array or waveguide array made of laser material based on phonon-assisted transition. The multi-path detection laser is emitted at a preset emission angle into the detection area to detect obstacles, and echo signals of different wavelengths are received based on the detection results; The echo signals of different wavelengths are calibrated by a wavelength identifier, so that the echo signals of different wavelengths are separated from each other at different angles, and the calibrated echo signals are obtained. Based on the comparative analysis results of the calibrated echo signal and the local oscillator signal, the measurement distance under each channel is obtained.

2. The method according to claim 1, characterized in that, The determination of the measurement distance for each channel is obtained based on the comparison and analysis results of the calibrated echo signal and the local oscillator signal, including: The signal processor is used to acquire the local oscillator signal and the calibrated echo signal; By comparing the signal delays of the local oscillator signal and the calibrated echo signal, the initial measurement distance for each channel is calculated based on the delay comparison results. The final measurement distance for each channel is obtained by compensating and correcting the initial optical path generated by the optical path.

3. A system for implementing the method of a wavelength-conversion-based solid-state radar as described in any one of claims 1-2, characterized in that, The radar system includes: an initial light source, a signal modulator, an amplifier, a beam splitter, a wavelength converter, a signal transmitter, a wavelength identifier, a detector, and a data processor; wherein, The initial light source is used to generate a continuous laser light source of the first wavelength; The signal modulator is used to modulate the laser source into a local oscillator signal; The amplifier is used to amplify the power of the local oscillator signal; The beam splitter is used to divide the amplified local oscillator signal into multiple local oscillator signals; The wavelength converter is used to convert the multiple local oscillator signals of the first wavelength into multiple local oscillator signals of their respective second wavelengths; the wavelength converter is an optical fiber array or waveguide array made of laser material based on phonon-assisted transition; The signal transmitter is used to transmit multiple local oscillator signals of the second wavelength to the detection area at a preset transmission angle to generate echo signals of different wavelengths; the signal transmitter is a bundled fiber transmitter or an integrated optical waveguide transmitter, and each detection laser is distributed in the signal transmitter at a set azimuth angle; The wavelength identifier is used to identify echo signals of different wavelengths, so that echo signals of different wavelengths are separated from each other at different angles. The detector is used to independently couple the echo signals of each wavelength after separation to the corresponding photoelectric detection unit and convert them into electrical signals, so as to eliminate crosstalk between different channels. The data processor is used to convert the electrical signal into a measured distance value and obtain point cloud coordinates based on the initial azimuth angles of each path.

4. The system according to claim 3, characterized in that, The wavelength identifier includes one of a dispersive element and a bandpass element; wherein the dispersive element includes one of a grating and a prism, and the bandpass element includes one of a bandpass filter, a thin film, and a photonic bandgap fiber.

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