A laser radar system with optical communication function

Abstract

The application relates to a laser radar system with an optical communication function, and belongs to the technical field of laser radars and wireless optical communication. The application realizes the integration of laser three-dimensional imaging and wireless optical communication functions; the optical communication mode greatly reduces the optical alignment requirement, compared with common wireless optical communication modes, and does not need a complex automatic capture tracking device; three-dimensional imaging and wireless optical communication both adopt the same hardware circuit and the same optical structure, compared with traditional devices for realizing the two functions, which need two independent systems, the system design is simplified; the wireless optical communication realized by the application has a bidirectional communication function, supports maintaining communication between the same device and multiple devices, can realize optical communication networking, optical communication relaying and other purposes, adopts invisible light sources, has strong directivity, is not easy to intercept and destroy, and can be applied to complex electromagnetic environments.

Description

Technical Field

[0001] This invention belongs to the field of lidar and wireless optical communication technology, and relates to a lidar system with optical communication function. Background Technology

[0002] LiDAR plays a crucial role in civilian applications such as robotics, autonomous driving, and smart cities. Solid-state LiDAR, with its lack of moving parts, offers higher reliability and thus boasts greater application prospects. In obstacle avoidance navigation for ground-based unmanned platforms, collision avoidance reconnaissance for drones, and collaborative applications between drone swarms and ground platforms, LiDAR will become a vital sensor.

[0003] Wireless optical communication technology has the advantage of good confidentiality and is an indispensable means of information exchange in complex electromagnetic environments. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The technical problem to be solved by this invention is: how to design a system based on an array detector that can acquire three-dimensional images of the illuminated scene and also realize optical communication between lidars within a certain distance range.

[0006] (II) Technical Solution

[0007] To address the aforementioned technical problems, this invention provides a lidar system with optical communication capabilities, comprising a laser emitting component, an array detection component, a control and processing component, and an optical component.

[0008] The laser emitting component consists of an electrically addressed vertical cavity surface emitting laser (VCSEL) array and a multi-channel narrow pulse driving circuit; the array detection component consists of a single-photon detector array and a signal extraction and readout circuit; the control and processing component consists of a system control module and a signal processing module; and the optical component consists of a transmitting and receiving optical antenna.

[0009] The VCSEL electrically controlled addressing array includes multiple laser emitting units;

[0010] The laser emitting component is used to output pulsed laser, wherein the pulsed laser includes multiple different pulse sequences; the laser emitting unit is a single-junction or multi-junction cascaded VCSEL laser, the laser emitting unit in the VCSEL electrically controlled addressing array is selected by electrical signal control, the selected laser emitting unit is driven by a multi-channel narrow pulse driving circuit to generate narrow pulse laser, and is emitted through the transmitting optical antenna in the optical component;

[0011] The array detection component is used to detect incident laser light waves or background light waves received by the receiving optical antenna in the optical component. The single-photon detector array includes multiple single-photon-responsive avalanche photodiodes for converting incident photons into electrical signals.

[0012] The signal extraction and readout circuit is used to extract the output signal of the single-photon detector array and transform the output signal into a corresponding form according to the system control requirements for system control readout or direct output. The signal extraction and readout circuit includes a signal extraction module and a readout circuit. The signal extraction module is used to convert the weak photocurrent signal of the single-photon detector array into a digital logic pulse signal of a certain level. The readout circuit is used to control the working mode of the array detection component. In the corresponding working mode, the digital logic pulse signal is processed according to the system control requirements to generate new information. In the signal readout stage, the new information is transmitted to the control and processing component through the data interface.

[0013] The array detection component has three operating modes: photon counting mode, time interval measurement mode, and pulse output mode.

[0014] In photon counting mode, the readout circuit accumulates the number of digital logic pulse signals inside the time-selection gate, that is, the count value is incremented by one for each pulse signal until the time-selection gate ends; in photon counting mode, the corresponding VCSEL array light-emitting unit does not emit laser light.

[0015] In time interval measurement mode, the readout circuit inputs the digital logic pulse signal into a time interval measurement unit (TDC). The TDC is cleared at a uniform start signal. When the rising edge of the digital logic pulse signal is detected, the TDC outputs the time interval corresponding to the time interval from the start signal to the rising edge of the digital logic pulse signal. For each pulse, the TDC outputs a corresponding time interval measurement value. The readout circuit temporarily stores the time interval in a first-in-first-out readout queue. The received time interval measurement values ​​are treated as encoded pulse sequences according to the time interval values. Correlation operations are performed with the encoded sequence of emitted laser pulses. If the correlation operation result exceeds a set threshold, the delay time and correlation result value are recorded.

[0016] In pulse output mode, the readout circuit directly connects the digital logic pulse signal corresponding to the selected detection unit to a dedicated output channel and sends it to the control and processing components.

[0017] The control and processing components are used to control the laser emitting components and array detection components to enter the corresponding working states and control the transmission and reception timing and signal readout timing, and to process the readout signals to obtain the corresponding information; wherein, the system control module controls the laser emitting units in the VCSEL electronically controlled addressable array to select at the same time, controls the working state of the entire or partial area of ​​the array detection components in real time through signal lines, controls the laser emitting units in the VCSEL electronically controlled addressable array to generate the emission timing according to the laser pulse coding sequence, and controls the receiving timing and signal readout timing of the array detection components;

[0018] The signal processing module receives the detector digital signal input from the array detection component. When the current array detection component or the area of ​​the array detection component is in photon counting mode, the signal processing module processes the received count value of each unit into a grayscale image.

[0019] When the current array detection component or array detection area is in time interval measurement mode, the signal processing module will correct the received delay time and related result values ​​into distance information according to the flight time.

[0020] When the current array detection component or array detection area is in pulse output mode, the signal processing module will determine its signal processing method according to the current working mode of the device; when the device is in lidar working mode, the signal processing module will compare the digital logic pulse sequence with the set communication request sequence, and decide whether to enter the communication mode according to the comparison result and the corresponding workflow; when the device is in laser communication mode, the signal processing module will output its encoded information "0" or "1" according to a certain rule based on the number of high and low levels in the same time period of several adjacent output digital logic pulse sequences.

[0021] Preferably, the number of addressable cells in the VCSEL electronically controlled addressable array is the same as the number of channels in the multi-channel narrow pulse drive circuit, that is, one addressable cell corresponds to one channel of narrow pulse drive circuit; or, the number of addressable cells in the VCSEL electronically controlled addressable array is a multiple of the number of channels in the multi-channel narrow pulse drive circuit, that is, multiple addressable cells correspond to one channel of narrow pulse drive circuit; by selecting different addressable cells in different time periods, multiple addressable cells can share one channel of narrow pulse drive circuit.

[0022] Preferably, a microlens array is mounted on the front end of the single-photon detector array.

[0023] Preferably, the entire array detection component is in one of three operating modes at the same time; or, the entire array detection component is divided into multiple regions, each region may be in a different operating mode at the same time, and correspondingly, each region may have its own independent data interface for interacting with the control and communication components.

[0024] Preferably, the photon counting mode count value is related to the background light intensity and the dark count.

[0025] Preferably, in pulse output mode, when the system is in lidar working mode, the laser pulse coding sequence is a pseudo-random pulse code stream or other pulse code stream with a certain length set by the system.

[0026] Preferably, in pulse output mode, when the system is in laser communication mode, the laser pulse encoding sequence is arranged according to the system communication content or communication protocol.

[0027] Preferably, the signal processing module infers the background light intensity within the received field of view based on the count value, and adjusts the detection threshold when the lidar is in operation mode accordingly, or determines whether there is a possible laser communication request based on adjacent count values ​​and their correlation.

[0028] Preferably, when the device is in laser communication mode, the signal processing module also decodes the output sequence according to the communication protocol and extracts its effective information for use by the upper layer application.

[0029] Preferably, each device's communication mode includes both transmitting and receiving directions, and multiple devices establish a relay or network state through bidirectional communication.

[0030] (III) Beneficial Effects

[0031] Compared with existing technologies, the beneficial effects of this invention are as follows: it integrates laser 3D imaging and wireless optical communication functions; the optical communication method adopted greatly reduces the requirements for optical alignment, and compared with common wireless optical communication methods, it eliminates the need for complex automatic acquisition and tracking devices; both 3D imaging and wireless optical communication use the same hardware circuitry and the same optical structure, simplifying system design compared to traditional devices that require two independent systems to achieve these two functions; the wireless optical communication implemented by this invention has bidirectional communication capabilities and supports communication between the same device and multiple devices, enabling optical communication networking, optical communication relay, and other purposes; it uses an invisible light source, has strong directionality, is not easily intercepted or damaged, and is suitable for complex electromagnetic environments; this invention uses a high-sensitivity single-photon detector array as the receiving device for laser 3D imaging and optical communication, which greatly reduces the requirements for laser emission power; this invention has no mechanical moving parts, which helps improve system reliability. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a lidar with optical communication function according to the present invention;

[0033] Figure 2 This is a schematic diagram showing the regional operating mode settings of the detection component;

[0034] Figure 3 This is a schematic diagram illustrating the related operations between the received pulse train and the transmitted pulse train;

[0035] Figure 4 This is a flowchart illustrating the regional operation mode of lidar.

[0036] Figure 5 This is a flowchart illustrating the workflow of the communication initiator switching communication modes;

[0037] Figure 6 This is a flowchart illustrating the workflow of the communication receiver switching communication modes.

[0038] Figure 7 This is a schematic diagram of the detection component in communication mode;

[0039] Figure 8 This is a configuration diagram for bidirectional communication;

[0040] Figure 9 This is a configuration diagram of three-way communication. Detailed Implementation

[0041] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0042] In existing devices, lidar and wireless optical communication typically require separate devices to perform their respective functions. The purpose of this invention is to provide a lidar system capable of integrating laser 3D imaging and wireless optical communication functions within a single device; that is, the device can operate in both lidar and laser communication modes.

[0043] The present invention provides a lidar system (solid-state lidar) with optical communication function, comprising a laser emitting component, an array detection component, a control and processing component, and an optical component;

[0044] The laser emitting component consists of an electrically addressed vertical cavity surface emitting laser (VCSEL) array and a multi-channel narrow pulse driving circuit; the array detection component consists of a single-photon detector (SPAD) array and a signal extraction and readout circuit; the control and processing component consists of a system control module and a signal processing module; and the optical component consists of a transceiver optical antenna.

[0045] The VCSEL electrically controlled addressable array includes multiple laser light-emitting units.

[0046] The laser emitting component is used to output pulsed laser, wherein the pulsed laser includes multiple different pulse sequences; the laser emitting unit is a single-junction or multi-junction cascaded VCSEL laser, and the laser emitting unit in the VCSEL electrically controlled addressing array is selected by electrical signal control, and the selected laser emitting unit is driven by a multi-channel narrow pulse driving circuit to generate narrow pulse laser.

[0047] Optionally, the number of addressable cells in the VCSEL electronically controlled addressable array is the same as the number of channels in the multi-channel narrow pulse drive circuit, meaning one addressable cell (VCSEL cell) corresponds to one channel of narrow pulse drive circuit; or, the number of addressable cells in the VCSEL electronically controlled addressable array is a multiple of the number of channels in the multi-channel narrow pulse drive circuit, meaning multiple addressable cells correspond to one channel of narrow pulse drive circuit. In this case, by selecting different addressable cells at different time periods, multiple addressable cells can share a single channel of narrow pulse drive circuit.

[0048] The array detection component is used to detect incident laser light waves or background light waves. The single-photon detector array includes multiple single-photon-responsive avalanche photodiodes, which are used to convert incident photons into electrical signals.

[0049] The optional single-photon detector array can be fitted with a microlens array at the front end, corresponding one-to-one with the detection unit, to improve the duty cycle.

[0050] The signal extraction and readout circuit is used to extract the output signal of the single-photon detector array and transform the output signal into a corresponding form according to system control requirements, for system control readout or direct output. The signal extraction and readout circuit includes a signal extraction module and a readout circuit. The signal extraction module converts the weak photocurrent signal of the single-photon detector array into a digital logic pulse signal of a certain level. The readout circuit controls the operating mode of the array detection components. In the corresponding operating mode, it processes the digital logic pulse signal according to system control requirements, generating new information. During the signal readout stage, the new information is transmitted to the control and processing components through a data interface.

[0051] Among them, the optional array detection component operating modes include photon counting mode, time interval measurement mode, and pulse output mode.

[0052] Optionally, the entire array detection component may be in one of three operating modes at the same time; or, the entire array detection component may be divided into multiple regions, each of which may be in a different operating mode at the same time. Accordingly, each region may have its own independent data interface for interacting with the control and communication components.

[0053] In photon counting mode, the readout circuit accumulates the number of digital logic pulse signals from the detector unit within the time-gated gate; that is, the count value increments by one for each incoming pulse signal until the time-gated gate closes. It should be noted that, typically in photon counting mode, the VCSEL array light-emitting unit corresponding to the detector unit does not emit laser light; that is, the photon counting value is related to the background light intensity and the dark count.

[0054] In time interval measurement mode, the readout circuit connects the digital logic pulse signal to a time interval measurement unit (TDC). The TDC is cleared at a uniform start signal. When the rising edge of the digital logic pulse signal is detected, the TDC outputs the time interval corresponding to the time interval from the start signal to the rising edge of the digital logic pulse signal. For each pulse, the TDC outputs a corresponding time interval measurement value. The readout circuit temporarily stores the time interval in a first-in-first-out readout queue. The received time interval measurement values ​​are treated as coded pulse sequences according to the time interval values. Correlation operations are performed with the emitted laser pulse coded sequence. If the correlation operation result exceeds a set threshold, the delay time and correlation result value are recorded.

[0055] In pulse output mode, the readout circuit directly connects the digital logic pulse signal corresponding to the selected detection unit to a dedicated output channel and sends it to the control and processing components.

[0056] The control and processing components are used to control the laser emitting components and array detection components to enter the corresponding working states and control the transmission and reception timing, signal readout timing, and process the readout signals to obtain the corresponding information. Specifically, the system control module simultaneously selects the laser emitting units in the VCSEL electrically controlled addressable array, controls the working state of the entire array detection component or a portion thereof in real time through signal lines, controls the laser emitting units in the VCSEL electrically controlled addressable array to generate emission timing according to the laser pulse coding sequence, and controls the receiving timing and signal readout timing of the array detection components.

[0057] Optionally, when the system is in lidar operating mode, the laser pulse coding sequence can be a pseudo-random pulse code stream set by the system or other pulse code streams with a certain length.

[0058] When the system is in laser communication mode, the laser pulse coding sequence is arranged according to the system communication content or communication protocol.

[0059] The signal processing module receives the detector digital signal input from the array detection component. When the current array detection component or the area of ​​the array detection component is in photon counting mode, the signal processing module processes the received count value of each unit into a grayscale image.

[0060] Optionally, the background light intensity within the received field of view can be inferred based on the count value of each unit, and the detection threshold in the lidar's operating mode can be adjusted accordingly to reduce the false alarm rate of single-photon detection. Alternatively, the possibility of a laser communication request can be determined based on the count values ​​and correlation of several adjacent units.

[0061] When the current array detection component or array detection area is in time interval measurement mode, the signal processing module corrects the received delay time and related result values ​​into distance information according to the flight time.

[0062] When the current array detection component or array detection area is in pulse output mode, the signal processing module will determine its signal processing method according to the current operating mode of the device. When the device is in lidar operating mode, the signal processing module compares the digital logic pulse sequence with the set communication request sequence, and decides whether to enter communication mode based on the comparison result and the corresponding workflow. When the device is in laser communication mode, the signal processing module outputs the encoded information "0" or "1" of the output digital logic pulse sequences of several adjacent units according to certain rules based on the number of high and low levels in the same time period. Optionally, the output sequence is decoded according to the communication protocol to extract its valid information for use by the upper layer application.

[0063] Each device's communication mode includes both sending and receiving directions, and multiple devices can establish a relay or network status through bidirectional communication.

[0064] like Figure 1 The diagram shown is a schematic of a lidar system (solid-state lidar) with optical communication function according to the present invention. The laser emitting component consists of an electrically controlled addressed VCSEL array light-emitting chip and a multi-channel narrow pulse driving circuit. The array detection component consists of a single-photon detection array and a signal extraction and readout circuit. The control and processing component consists of system control and signal processing. The optical component consists of transceiver optical antennas. The receiving optical antenna is used to collect echo signals within the receiving field of view. To reduce the influence of background light, the receiving optical design should include narrowband optical filtering. The emitting optics completes VCSEL beam shaping, and the emitted laser covers the target scene.

[0065] In this embodiment, the VCSEL array light-emitting chip operates around 850nm, with selectable wavelengths including 905nm or 940nm. The invention itself does not limit the choice of wavelength, but changes in the laser wavelength require the detector's operating band to match. For example, if a 1550nm VCSEL array is used, it needs to be replaced with an InGaAs compound matrix detector assembly.

[0066] For the detection components of an 850nm VCSEL array, silicon-based detectors can be used. Silicon single-photon avalanche diode arrays can reach scales of hundreds of thousands or even millions of units, with unit pixel sizes maintained on the order of 10 micrometers. Each unit has a quenching circuit, and the detector dead time can be in the nanosecond range, thus the count rate can exceed one hundred megaseconds, while the unit dark count rate can be as low as the kHz range. The photon detection efficiency exceeds 20%, and the time jitter is on the order of hundreds of picoseconds. Therefore, silicon-based SPAD arrays are very suitable for near-infrared single-photon active and passive detection, and there are mature commercial devices available, such as Sony's IMX479 detector component.

[0067] To facilitate the explanation of the relevant content of this invention, the pixel size of the detection component array in this embodiment is set to 600×200, corresponding to a detection field of view of 60°×20° in the lidar working mode. The illumination field of view of the VCSEL array is adapted accordingly. It can directly cover the entire field of view through the VCSEL array, or it can cover the detection field of view through a suitable beam deflection method (optical-mechanical deflection or electronically controlled deflection). This embodiment does not limit this. For ease of description, the following description takes the method of directly covering the entire field of view with the VCSEL array as an example.

[0068] In lidar operation mode, the device can acquire grayscale and depth images of the corresponding illumination field of view. If a flash operation mode is used, the VCSEL array needs to illuminate the entire field of view simultaneously, requiring the driving circuit to drive all VCSEL units concurrently, resulting in a complex and difficult-to-implement circuit. Using an addressable VCSEL array and time-division multiplexing of multi-channel driving circuitry reduces the electrical design complexity of the transmitting components. The detection components working in conjunction with the addressable VCSEL array are divided into multiple regions, such as... Figure 2 As shown, the detection array in this embodiment is divided into four regions, and the corresponding VCSEL array also has four regions. At time 1, detection component regions 1 and 3 operate in photon counting mode, detection component regions 2 and 4 operate in time interval measurement mode, and the VCSEL array regions 1 and 3, which correspond one-to-one with their fields of view, are not operating. VCSEL array regions 2 and 4 are connected to the multi-channel drive circuit via addressing and emit corresponding laser pulses. At time 2, the operating modes of the regions are reversed compared to time 1. In actual operation, the emitting components alternate between operating and non-operating states, and the operating modes of the detection components alternate. Each region of the detection components has an independent data and control connection interface with the control and processing components. This operating method also speeds up signal readout and processing. It should be noted that dividing the array into four regions in this example is only for illustrative purposes; any actual region division that meets design requirements is reasonable.

[0069] When the VCSEL array is operating, the driving circuit drives the VCSEL units to emit narrow-pulse laser trains, each with a width ranging from sub-nanosecond to nanosecond. To reduce the influence of external interference, the laser trains are encoded using pseudo-random pulse position coding or other orthogonal coding schemes with good autocorrelation. The encoded laser train is transmitted simultaneously to the readout circuit of the detection component according to a predetermined protocol. The coding interval and laser pulse train length are pre-designed based on information such as echo photon intensity, background intensity, and required detection probability. In this embodiment, the designed average coding interval is 10 ns, and the pulse train length is 20 pulses.

[0070] In photon counting mode, the readout circuit counting logic array in the detection component is connected to the corresponding area. The set photon counting time is on the order of tens to hundreds of microseconds. During this time period, the detection unit is triggered by background photon or dark counts. Each trigger increments the counting logic value by one until the counting time ends and the counting stops and is temporarily stored. Then, according to the array processing method, the counting information is read out by the readout circuit and sent to the signal processing for further processing to obtain the background light count.

[0071] In time interval measurement mode, the readout circuit TDC logic array in the detection component is connected to the corresponding area. The working time length is set according to the device's working distance measurement range and the duration of the emitted pulse train. Assuming a working distance of 600m, the time interval working length is less than 5µs. Assuming a TDC time resolution of 200ps, the TDC timing length requires 15 bits. During this time period, the detection unit is triggered by laser echo photons, background photons, and dark counts. Each trigger outputs a TDC timestamp, which is stored in a first-in-first-out (FIFO) queue. In this embodiment, the FIFO length is 42. A corresponding time interval measurement value is output, and the readout circuit temporarily stores this time interval in the FIFO readout queue. The received time interval measurement values ​​are treated sequentially as encoded pulse sequences according to the time interval values, and correlated with a pre-set currently emitted laser pulse encoding sequence. The calculation process is illustrated below. Figure 3As shown, in the received sequence, the dashed lines represent non-laser echo triggering. Each time new data enters the first-in-first-out queue, the transmitted and received sequences are processed in real-time by hardware. Even with imperfect matching, the received pulse sequence and the transmitted sequence still exhibit good correlation. The correlation calculation result can filter out noise, and sufficient detection probability can be maintained through the cumulative detection of multiple pulses. If the correlation calculation result exceeds a set threshold, the delay time and correlation result value are recorded and output to the output queue. Each pixel's output queue is designed to record four results, resulting in four echoes. If more than four echoes are recorded, hardware design ensures the recording of the first three and the last echoes. When the working time ends, according to the array processing method, the delay time information and correlation result value information in the output queue are read out by the readout circuit and sent to the signal processing unit for ranging signal processing to obtain distance information.

[0072] Therefore, when the device is in lidar working mode, the workflow diagram for using a zoned working method is as follows: Figure 4 As shown, multiple regions operate in parallel under two different modes: photon counting and time interval measurement. The decision to terminate the current frame processing is made by determining whether all regions have been traversed. Specifically, if abnormally high-count pixel clusters are detected in the array grayscale image during background light signal processing, possibly due to illumination from the communication initiator, and the system allows entry into communication mode, then the communication docking judgment process begins. Furthermore, based on the current changes in background light count, changes in background light intensity can be inferred. According to a pre-calibrated false alarm rate and the correspondence between background light intensity and the counting threshold, the counting threshold is adjusted to keep false alarms within a controllable range during the detection process.

[0073] Because the detector's dead time is less than 10ns, the maximum acceptable trigger frequency can exceed 100MHz, thus the upper limit of single-channel communication rate exceeds 100Mbps. When the device needs to communicate, the communication initiator's workflow is as follows: Figure 5 As shown, the initiator will stop sending the laser pulse sequence used for ranging in the direction where a communication receiver might exist, drive the corresponding VCSEL unit to emit the agreed communication request sequence, and set the detection array in the corresponding direction to communication mode. The laser beam dispersion emitted for communication needs to be set appropriately to ensure that it can cover a certain number of pixel units on the detection array of the possible communication receiver. In this embodiment, the laser beam dispersion is set to be no less than 1°. When a response is received within a specified time, the communication mode is entered. Otherwise, if the number of no responses exceeds a set threshold, it is assumed that there is no communication receiver in that direction, and the search for a communication receiver is switched to the next direction.

[0074] The corresponding communication receiver's workflow is as follows: Figure 6As shown, during the communication docking judgment phase, it is repeatedly confirmed that the issue is not due to noise or accidental factors before setting the corresponding receiving area to communication decoding mode. In communication decoding and communication mode, the triggering of the corresponding detection unit is directly connected to signal processing, then the communication request sequence is judged, a response sequence is sent, and the communication mode is entered. When there is no activity on the communication link for a certain period of time, the communication receiver will automatically exit the communication mode.

[0075] In communication mode, the light spot of the communication initiator will cover a certain number of pixels on the receiver's detection array. In this embodiment, a 1° light spot will cover approximately 80 pixels on the receiver's detection array. Figure 7 As shown. For ease of explanation, assume the light spot covers at least 16 SPAD units, and the trigger logic pulses for the corresponding SPAD units are directly output to the signal processing. Based on the premise that the laser signals arrive simultaneously and noise arrives randomly, the signal processing confirms the presence of a laser pulse by detecting whether the number of SPAD units triggered simultaneously at the same time exceeds a threshold. Figure 7 In this process, the number of triggering units when the laser arrives is much greater than the number of triggering units when the non-laser arrives.

[0076] Because the beam divergence of laser emission exceeds 1°, corresponding to a communication distance of over 1km, and the spot size exceeds 17m, the receiver can easily be covered by the emitter's beam. Figure 8 As shown, two identical devices can provide bidirectional communication. To avoid signal loss during large angle changes, multiple VCSELs can be driven simultaneously to expand the laser irradiation angle range.

[0077] like Figure 9 As shown, three-way communication can be achieved through relaying between devices. Figure 9 In this example, devices 2 and 3 communicate indirectly through device 1. Similarly, multiple devices can form a communication network to exchange information among themselves.

[0078] As can be seen, in this invention, the laser emitting component consists of an electrically addressed VCSEL array light-emitting chip and a multi-channel narrow pulse driving circuit; the array detection component consists of a single-photon detection array (SPAD detection array) and a signal extraction and readout circuit; the control and processing component consists of system control and signal processing; and the optical component consists of transceiver optical antennas. In lidar operating mode, the multi-channel driving circuit drives the electrically addressed VCSEL array to emit a large field-of-view pulse train sequence, the SPAD detection array completes photoelectric conversion, and signal processing acquires the depth and grayscale image of the illuminated scene. In laser communication mode, the corresponding unit of the VCSEL array in the communication transmission path emits corresponding laser coded pulses according to the input communication code stream, and the incident beam in the communication receiving path covers a certain number of pixels of the SPAD detection array. Signal processing decodes the output communication code stream by comparing a threshold with the number of simultaneously triggered pixels. This invention is suitable for three-dimensional environmental perception and information exchange with a certain degree of confidentiality between multiple platforms and equipment in applications such as vehicle-mounted, low-altitude reconnaissance and mapping, and UAV-ground platform collaboration.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A lidar system with optical communication function, characterized in that, Includes laser emitting components, array detection components, control and processing components, and optical components; The laser emitting component consists of an electrically addressed vertical cavity surface emitting laser (VCSEL) array and a multi-channel narrow pulse driving circuit; the array detection component consists of a single-photon detector array and a signal extraction and readout circuit; the control and processing component consists of a system control module and a signal processing module; and the optical component consists of a transmitting and receiving optical antenna. The VCSEL electrically controlled addressing array includes multiple laser emitting units; The laser emitting component is used to output pulsed laser, wherein the pulsed laser includes multiple different pulse sequences; the laser emitting unit is a single-junction or multi-junction cascaded VCSEL laser, the laser emitting unit in the VCSEL electrically controlled addressing array is selected by electrical signal control, the selected laser emitting unit is driven by a multi-channel narrow pulse driving circuit to generate narrow pulse laser, and is emitted through the transmitting optical antenna in the optical component; The array detection component is used to detect incident laser light waves or background light waves received by the receiving optical antenna in the optical component. The single-photon detector array includes multiple single-photon-responsive avalanche photodiodes for converting incident photons into electrical signals. The signal extraction and readout circuit is used to extract the output signal of the single-photon detector array and transform the output signal into a corresponding form according to the system control requirements for system control readout or direct output. The signal extraction and readout circuit includes a signal extraction module and a readout circuit. The signal extraction module is used to convert the weak photocurrent signal of the single-photon detector array into a digital logic pulse signal of a certain level. The readout circuit is used to control the working mode of the array detection component. In the corresponding working mode, the digital logic pulse signal is processed according to the system control requirements to generate new information. In the signal readout stage, the new information is transmitted to the control and processing component through the data interface. The array detection component has three operating modes: photon counting mode, time interval measurement mode, and pulse output mode. In photon counting mode, the readout circuit accumulates the number of digital logic pulse signals inside the time-selection gate, that is, the count value is incremented by one for each pulse signal until the time-selection gate ends; in photon counting mode, the corresponding VCSEL array light-emitting unit does not emit laser light. In time interval measurement mode, the readout circuit inputs the digital logic pulse signal into a time interval measurement unit (TDC). The TDC is cleared at a uniform start signal. When the rising edge of the digital logic pulse signal is detected, the TDC outputs the time interval corresponding to the time interval from the start signal to the rising edge of the digital logic pulse signal. For each pulse, the TDC outputs a corresponding time interval measurement value. The readout circuit temporarily stores the time interval in a first-in-first-out readout queue. The received time interval measurement values ​​are treated as encoded pulse sequences according to the time interval values. Correlation operations are performed with the encoded sequence of emitted laser pulses. If the correlation operation result exceeds a set threshold, the delay time and correlation result value are recorded. In pulse output mode, the readout circuit directly connects the digital logic pulse signal corresponding to the selected detection unit to a dedicated output channel and sends it to the control and processing components. The control and processing components are used to control the laser emitting components and array detection components to enter the corresponding working states and control the transmission and reception timing and signal readout timing, and to process the readout signals to obtain the corresponding information; wherein, the system control module controls the laser emitting units in the VCSEL electronically controlled addressable array to select at the same time, controls the working state of the entire or partial area of ​​the array detection components in real time through signal lines, controls the laser emitting units in the VCSEL electronically controlled addressable array to generate the emission timing according to the laser pulse coding sequence, and controls the receiving timing and signal readout timing of the array detection components; The signal processing module receives the detector digital signal input from the array detection component. When the current array detection component or the area of ​​the array detection component is in photon counting mode, the signal processing module processes the received count value of each unit into a grayscale image. When the current array detection component or array detection area is in time interval measurement mode, the signal processing module will correct the received delay time and related result values ​​into distance information according to the flight time. When the current array detection component or array detection area is in pulse output mode, the signal processing module will determine its signal processing method according to the current working mode of the device; when the device is in lidar working mode, the signal processing module will compare the digital logic pulse sequence with the set communication request sequence, and decide whether to enter the communication mode according to the comparison result and the corresponding workflow; when the device is in laser communication mode, the signal processing module will output its encoded information "0" or "1" according to a certain rule based on the number of high and low levels in the same time period of several adjacent output digital logic pulse sequences.

2. The system as described in claim 1, characterized in that, The number of addressable cells in the VCSEL electronically controlled addressable array is the same as the number of channels in the multi-channel narrow pulse drive circuit, that is, one addressable cell corresponds to one channel of narrow pulse drive circuit. Alternatively, the number of addressable cells in the VCSEL electronically controlled addressable array is a multiple of the number of channels in the multi-channel narrow pulse drive circuit, that is, multiple addressable cells correspond to one channel of narrow pulse drive circuit; by selecting different addressable cells at different time periods, multiple addressable cells can share one channel of narrow pulse drive circuit.

3. The system as described in claim 1, characterized in that, A microlens array is mounted on the front end of a single-photon detector array.

4. The system as described in claim 1, characterized in that, The entire array detection component can operate in one of three modes simultaneously; or, the entire array detection component can be divided into multiple regions, each of which may operate in a different mode at the same time. Accordingly, each region can have its own independent data interface for interacting with the control and communication components.

5. The system as described in claim 1, characterized in that, The photon counting mode count value is related to the background light intensity and the dark count.

6. The system as described in claim 1, characterized in that, In pulse output mode, when the system is in lidar working mode, the laser pulse coding sequence is a pseudo-random pulse code stream or other pulse code streams with a certain length set by the system.

7. The system as described in claim 1, characterized in that, In pulse output mode, when the system is in laser communication mode, the laser pulse encoding sequence is arranged according to the system communication content or communication protocol.

8. The system as described in claim 1, characterized in that, The signal processing module infers the background light intensity within the receiving field of view based on the count value, and adjusts the detection threshold when the lidar is in operation mode accordingly, or determines whether there is a possible laser communication request based on adjacent count values ​​and their correlation.

9. The system as described in claim 1, characterized in that, When the device is in laser communication mode, the signal processing module also decodes the output sequence according to the communication protocol and extracts its valid information for use by the upper layer application.

10. The system as described in any one of claims 1 to 9, characterized in that, Each device's communication mode includes both sending and receiving directions, and multiple devices can establish a relay or network status through bidirectional communication.

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