Speed measurement method and device, and laser radar system

Abstract

A speed measurement method and device, and a laser radar system. The laser radar system comprises a laser transmitting module, a laser receiving module, and a data processing module. The laser transmitting module is used for transmitting a frame signal comprising multiple detection optical signals, and the laser receiving module is used for receiving echo signals of the multiple detection optical signals. In the frame signal transmission process, if a target to be measured moves in the radial direction, the time-of-flight difference between the multiple detection optical signals can be caused. Therefore, the data processing module is used for determining the time-of-flight difference between any two detection optical signals among the multiple detection optical signals, determining, on the basis of the transmission time interval between the two detection optical signals, the radial distance of said target moving in the time-of-flight difference, and then determining the radial speed of said target on the basis of the radial distance and the time-of-flight difference. The speed measurement method and device, and the laser radar system can be applied to a detection or sensing system of a new energy vehicle or an intelligent vehicle, so that the measurement efficiency and accuracy of the speed of objects can be improved.

Description

Speed ​​measurement method, device and laser radar system

[0001] This application claims priority to Russian patent application No. 2024104189 filed with the Russian Federal Intellectual Property Office on February 20, 2024, entitled “Method, device and lidar system for speed measurement”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of detection technology, and more specifically, to a speed measurement method, device and laser radar system. Background Art

[0003] With the advancement of automation technology, the demand for precise target velocity detection in fields such as intelligent driving is increasing. Among various detection sensors, lidar (LiDAR) is widely used in various detection devices due to its ability to acquire high-resolution three-dimensional spatial information, high ranging accuracy, and independence from external lighting conditions. LiDAR ranging technology encompasses various principles, among which direct time of flight (DTOF) is the most commonly used.

[0004] There are two common LiDAR DTOF velocity measurement schemes. The first uses multi-frame laser point cloud data and ego vehicle positioning information to determine the radial velocity between the detected target and the ego vehicle. The second determines the radial velocity between the detected target and the ego vehicle based on a single frame of laser point cloud data. However, both schemes have drawbacks when applied to the detected target's velocity measurement, resulting in an inability to accurately and timely determine the radial velocity of the detected target.

[0005] In view of this, how to accurately and quickly determine the radial velocity of the detected target based on the DTOF technology principle has become an urgent problem to be solved. Summary of the Invention

[0006] This application provides a velocity measurement method, device, and laser radar system capable of determining the radial velocity of a target using a single-frame laser signal. This method eliminates the need for the accumulation of multiple frames of laser point cloud data, thereby improving velocity measurement efficiency. Furthermore, the velocity measurement results are unaffected by the laser radar system's own positioning information, helping to ensure accuracy. Furthermore, this application utilizes the relatively mature DTOF technology to achieve velocity measurement, facilitating cost-effective speed measurement.

[0007] In a first aspect, a speed measurement method is provided, the method comprising: obtaining sampling information of each echo signal of at least two echo signals, and a transmission time interval of detection light signals corresponding to the at least two echo signals, the detection light signals corresponding to the at least two echo signals belonging to the same frame; determining a flight time corresponding to each echo signal based on the sampling information of each echo signal; determining a flight time difference based on the flight time corresponding to each echo signal; and determining a radial velocity of the target based on the transmission time interval and the flight time difference.

[0008] With the advancement of lidar technology, the number of parallel detection channels has increased. This means that at the same frame rate, the detection light signal emitted by the lidar stays at a certain location for a longer time. In other words, the frame length of each detection light signal has increased, reaching 1 millisecond or even longer. Therefore, if a target undergoes radial displacement during the transmission of a frame of detection light signal, the radial displacement and radial velocity of the target can be determined by the time-of-flight difference between at least two echo signals corresponding to that frame of detection light signal.

[0009] It should be noted that before obtaining the sampling information of each echo signal in at least two echo signals, the laser radar transmits at least two detection light signals to the same target in the same frame. The at least two detection light signals are reflected by the target to obtain echo signals. The echo signals of the at least two detection light signals include at least two echo signals.

[0010] Exemplarily, the sampling information for each echo signal is obtained by sampling the level signal output by a detector array detecting the echo signal. The detector array includes multiple array elements, each of which can independently respond to photons in the echo signal. Therefore, the sampling information for each echo signal can indicate the relationship between the time when multiple photons in the echo signal enter the detector array and the light intensity of the echo signal. Exemplarily, the time of incidence of the echo signal corresponding to the peak light intensity of the echo signal can be determined based on the sampling information. Furthermore, the time of flight of the echo signal can be determined based on the emission time of the detection light signal corresponding to the echo signal and the time of incidence of the echo signal corresponding to the peak light intensity of the echo signal. Therefore, the time of flight of each echo signal can be determined based on the sampling information of each echo signal.

[0011] In some implementations, determining the radial velocity of the target based on the transmission time interval and the flight time difference can be understood as determining the radial velocity of the target based on the flight time difference and the transmission time interval corresponding to the flight time difference. More specifically, determining the radial velocity of the target based on the transmission time interval and the flight time difference includes: determining the displacement of the target within the transmission time interval based on the transmission time interval corresponding to the flight time difference; and determining the radial velocity based on the displacement of the target and the flight time difference.

[0012] Exemplarily, the time-of-flight difference may be: the time-of-flight difference between the probe light signals corresponding to any two echo signals from the at least two echo signals, and the emission time interval corresponding to the time-of-flight difference is: the emission time interval between the probe light signals corresponding to the at least two echo signals. Alternatively, the time-of-flight difference may be: the average of the time-of-flight differences between two probe light signals separated by a fixed emission interval from the at least two echo signals, and the emission time interval corresponding to the time-of-flight difference is: the fixed emission interval. Exemplarily, if the emission time interval between two adjacent probe light signals is Δt, the fixed emission interval may be Δt, i.e., two probe light signals separated by a fixed emission interval are considered adjacent probe light signals; alternatively, the fixed emission interval may be nΔt, where n may be an integer greater than 1 and less than N-1, and N is the number of probe light signal shots in a frame (slot).

[0013] In this technical solution, a single-frame laser signal, including multiple detection light signals, can be used to determine the radial velocity of a target. This eliminates the need for overlaying multiple frames of point cloud data, improving the efficiency of determining target velocity. Furthermore, the velocity measurement results are unaffected by the LiDAR system's own positioning information, ensuring accuracy. Furthermore, this technical solution utilizes the relatively mature DTOF technology to achieve velocity measurement, enabling low-cost speed measurement.

[0014] In some implementations, the method further includes: obtaining sampling information for each of the at least two echo signals and a time interval between transmissions of the probe light signals corresponding to the at least two echo signals, where the probe light signals corresponding to the at least two echo signals belong to the same frame; determining a time-of-flight difference between a first echo signal and a second echo signal in the at least two echo signals based on the sampling information for each echo signal; and determining a radial velocity of the target based on the time interval and the time-of-flight difference between the probe light signals corresponding to the first echo signal and the second echo signal, respectively.

[0015] The first echo signal and the second echo signal may be any two echo signals among the at least two echo signals.

[0016] In combination with the first aspect, in certain implementations of the first aspect, the sampling information includes superimposed information output by multiple sampling points.

[0017] Exemplarily, each sampling point among the multiple sampling points is used to sample a detection result of an array element in the detector array (ie, a level signal output by an array element).

[0018] In the above technical solution, the information output by multiple sampling points is superimposed to obtain sampling information, which helps to increase the statistical sample and suppress random noise, thereby improving the accuracy of the moment when the echo signal is detected, thereby improving the accuracy of the flight time corresponding to the determined echo signal, and further improving the accuracy of the detected target radial velocity.

[0019] In combination with the first aspect, in certain implementations of the first aspect, a sum of a setup time and a hold time of a sampling circuit of each of the multiple sampling points is greater than or equal to one sampling period.

[0020] The sampling circuit is used to generate a sampling signal, which may be a clock signal.

[0021] In the above technical solution, the setup time and / or hold time of the sampling circuit are adjusted so that the sum of the two is greater than or equal to one sampling period. In this way, when the rising edge of the level signal corresponding to the echo signal arrives after the rising edge of the sampling signal, the sampling signal also has a certain probability of identifying the level signal, so that the sampling signal responds more sensitively to the jump moment of the level signal corresponding to the echo signal, which helps to improve the measurement accuracy of the moment when the echo signal enters the detector array, thereby improving the measurement accuracy of the flight time difference, and further improving the accuracy of the detected target radial velocity.

[0022] In combination with the first aspect, in certain implementations of the first aspect, the setup time and / or the hold time are adjusted according to environmental information.

[0023] In the above technical solution, the setup time and / or hold time of the sampling circuit are adjustable, which helps to improve the breadth and flexibility of application scenarios of the speed measurement method, thereby adapting to different hardware performances.

[0024] In combination with the first aspect, in certain implementations of the first aspect, the sampling information of one echo signal among at least two echo signals is obtained by sampling the level signal corresponding to the echo signal. The method also includes: before sampling the level signal, filtering the level signal, and the filtering process is used to slow down the transition edge slope of the level signal.

[0025] In the above technical solution, after the slope of the transition edge of the level signal slows down, the time between the intensity of the level signal reaching a certain signal intensity and the flipping of its transition edge increases, thereby increasing the probability that the transition edge of the level signal is recognized by the sampling signal. In this way, the sampling signal responds more sensitively to the transition moment of the level signal corresponding to the echo signal, which helps to improve the measurement accuracy of the moment when the echo signal enters the detector array, thereby improving the measurement accuracy of the flight time difference, and further improving the accuracy of the detected target radial velocity.

[0026] In combination with the first aspect, in certain implementations of the first aspect, the method is executed by a lidar system, and the method also includes: determining the emission time of the detection light signal corresponding to at least two echo signals based on the distance between the target and the lidar system.

[0027] In the above technical solution, the emission time of the detection light signals corresponding to at least two echo signals is determined based on the distance between the target and the lidar system, so that the rising edges of the level signals associated with the first few echo signals in the at least two echo signals fall within the metastable interval of a certain sampling period. In this way, if the target undergoes radial displacement during the emission of the detection light signals corresponding to the at least two echo signals, the radial velocity of the target can be measured from a single frame of laser signals by ensuring that the rising edges of the echo level signals associated with some of the at least two echo signals fall outside the metastable interval of the sampling period, thereby improving the efficiency of target velocity detection.

[0028] In a second aspect, a speed measuring device is provided, which includes an acquisition unit and a processing unit, wherein the acquisition unit is used to: acquire sampling information of each echo signal in at least two echo signals, and the emission time interval of the detection light signals corresponding to the at least two echo signals, and the detection light signals corresponding to the at least two echo signals belong to the same frame; the processing unit is used to: determine the flight time corresponding to each echo signal according to the sampling information of each echo signal; determine the flight time difference according to the flight time corresponding to each echo signal; and determine the radial velocity of the target according to the emission time interval and the flight time difference.

[0029] In combination with the second aspect, in some implementations of the second aspect, the processing unit is used to: determine the displacement of the target corresponding to the flight time difference based on the emission time interval; and determine the radial velocity based on the displacement and the flight time difference.

[0030] In combination with the second aspect, in certain implementations of the second aspect, the sampling information includes superimposed information output by multiple sampling points.

[0031] In combination with the second aspect, in certain implementations of the second aspect, a sum of a setup time and a hold time of a sampling signal of each sampling point among the multiple sampling points is greater than or equal to one sampling period.

[0032] In combination with the second aspect, in certain implementations of the second aspect, the setup time and / or the hold time are adjusted according to environmental information.

[0033] In combination with the second aspect, in certain implementations of the second aspect, the sampling information of one echo signal among at least two echo signals is obtained by sampling the level signal corresponding to the echo signal, and the processing unit is also used to: filter the level signal before sampling the level signal, and the filtering process is used to slow down the transition edge slope of the level signal.

[0034] In combination with the second aspect, in certain implementations of the second aspect, the device is arranged in a laser radar system, and the emission time of the detection light signal corresponding to at least two echo signals is determined according to the distance between the target and the laser radar system.

[0035] In a third aspect, a speed measuring device is provided, which includes: a memory for storing a computer program; and a processor for executing the computer program stored in the memory, so that the device performs the method in any possible implementation of the first aspect.

[0036] In a fourth aspect, a laser radar system is provided, which includes a laser transmitting module, a laser receiving module, and a device as in any possible implementation of the second aspect or the third aspect; wherein the laser transmitting module is used to transmit a detection light signal corresponding to at least two echo signals, and the laser receiving module is used to receive at least two echo signals.

[0037] In a fifth aspect, an intelligent driving device is provided, which includes an apparatus as in any possible implementation of the second aspect or the third aspect; or, the intelligent driving device includes a laser radar system as in any possible implementation of the fourth aspect.

[0038] In combination with the fifth aspect, in some implementations of the fifth aspect, the intelligent driving device is a vehicle.

[0039] In a sixth aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in any one of the possible implementations of the first aspect.

[0040] It should be noted that the above-mentioned computer program code may be stored in whole or in part on a first storage medium, wherein the first storage medium may be packaged together with the processor, or may be packaged separately from the processor.

[0041] In a seventh aspect, a computer-readable medium is provided, wherein the computer-readable medium stores instructions. When the instructions are executed by a processor, the processor implements the method in any possible implementation of the first aspect.

[0042] In an eighth aspect, a chip is provided, which includes a circuit for executing the method in any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic diagram showing the results of sampling different laser pulse echo signals by a single detector.

[0044] FIG2 is a schematic diagram showing the result of sampling the laser pulse echo signal by the detector array.

[0045] FIG3 is a schematic diagram of the sampling results of the detection signal of the detector array.

[0046] FIG4 is a schematic diagram of a speed measurement system provided in an embodiment of the present application.

[0047] FIG5 is a schematic flow chart of a speed measurement method provided in an embodiment of the present application.

[0048] FIG6 is another schematic diagram of the speed measurement system provided in an embodiment of the present application.

[0049] FIG7 is a schematic diagram of a trigger.

[0050] FIG8 is a diagram showing the relationship between setup-hold time and detection error probability.

[0051] FIG9 is a schematic diagram showing the effect of setup-and-hold time on sampling results.

[0052] FIG10 is another schematic diagram of the speed measurement system provided in an embodiment of the present application.

[0053] FIG11 is a schematic diagram showing a comparison of a level signal before and after filtering according to an embodiment of the present application.

[0054] FIG12 is a schematic diagram showing the effect of level signal filtering on sampling results provided by an embodiment of the present application.

[0055] FIG13 is a schematic diagram showing the influence of the laser pulse sending time determined according to the distance between the target and the laser radar on the sampling result.

[0056] FIG14 is a schematic block diagram of a speed measurement device provided in an embodiment of the present application.

[0057] FIG15 is another schematic block diagram of the speed measuring device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The technical solution in this application will be described below with reference to the accompanying drawings.

[0059] To facilitate understanding of the technical solution of this application, before introducing the technical solution, the technical concepts involved in this application are first introduced:

[0060] 1. DTOF: This refers to a technology that directly measures the time of flight of a detection light signal and determines the distance between the lidar and the detected target based on the time of flight. Specifically, the detection light signal emitted by the lidar illuminates the detected target and, after reflection from the target, produces an echo signal (or scattered light signal). The lidar then receives the echo signal. The time difference between the lidar transmitting the detection light signal and receiving the echo signal is the detection light signal's time of flight.

[0061] 2. Single-frame (slot or frame) laser signal: The detection light signal emitted by the lidar at a single angle (or within a single field of view). The following example uses a laser pulse as the detection light signal.

[0062] 3. Single laser pulse: A single shot of a detection light signal emitted by a laser radar. A single frame of laser signal may include multiple shots of detection light signals, i.e., a single frame of laser signal may include multiple laser pulses.

[0063] 4. Single photon avalanche diodes (SPAD) detectors: A Geiger-mode diode is cascaded with an active quenching circuit to obtain a SPAD detector. When more than one photon is incident on the photosensitive surface of the SPAD detector, once the photon is captured, a Geiger-mode saturated avalanche will be formed. After detecting the saturated output, the active quenching circuit uses a gate circuit to cut off the current conduction link of the diode, so that the SPAD detector has the ability to detect the next photon incident event. A single SPAD detector can only respond 0-1 to the presence or absence of a photon, and cannot detect the light intensity of a multi-photon signal. A SPAD detector array can be obtained by closely arranging several SPAD detectors. At this time, each array element in the SPAD detector array can independently respond to the photons that irradiate its photosensitive surface, so that the detection of light intensity can be achieved.

[0064] 5. Radial velocity: Also known as line-of-sight velocity, this refers to the velocity component of the target's motion in the LiDAR's line of sight (or observation direction). Correspondingly, the component of the target's displacement in the LiDAR's line of sight is called radial displacement.

[0065] As mentioned above, there are two types of commonly used lidar DTOF detection schemes. The first type uses multi-frame laser signals and self-vehicle positioning information to determine the radial velocity of the detected target. However, the above scheme requires obtaining continuous multi-frame point cloud data and completing target clustering, segmentation and inter-frame matching of the point cloud data before determining the target's speed. Among them, the processing of multi-frame point clouds leads to slow response time, and the post-processing of point cloud data is complex and has large errors, resulting in insufficient time to detect objects that suddenly appear at close range and in a short period of time, and the accuracy of the detection results also depends on high-precision self-vehicle positioning. The second type is to detect the speed of the target relative to the self-vehicle based on single-frame point cloud data. However, when the radial movement speed of the target is limited, due to the extremely short contact time between a single pulse and the target (about nanoseconds), the target can be considered to be stationary during the reflection process within a single frame, and the target's speed information cannot be accurately reflected.

[0066] For example, as shown in Figure 1(a), the laser radar's dwell time at the same angle is 1 millisecond (ms), meaning that the frame length corresponding to one frame of laser signal is 1ms. When using a single detector to detect the echo signals of two laser pulses within a single frame of laser signal, due to the limited resolution of clock sampling, the result of sampling the output value of a single detector may not reflect the difference in flight time between the two laser pulses caused by the motion of the target object. Figure 1(b) shows the detection and sampling results of two laser pulse echo signals, where laser pulse 1 and laser pulse 2 are two laser pulses in the same frame of laser signal. Furthermore, if we want to measure a target with a radial velocity of 10 m / s, and the maximum displacement Δd of the target object within the duration of a single laser signal frame is: Δd = 10 m / s * 1 ms = 10 mm, the corresponding change in the flight time of the laser pulse is: 66.7 picoseconds (ps). For example, if laser pulse 1 and laser pulse 2 are the first and last laser pulses in a laser signal frame with a frame length of 1 ms, the flight time difference between laser pulse 1 and laser pulse 2 should be 66.7 ps. If the sampling signal frequency is 1 gigahertz (GHz), that is, the sampling period is 1 nanosecond (ns), since 66.7 ps is much smaller than 1 ns, the flight time difference between the two laser pulses may not be distinguishable from the sampling results corresponding to the echo signals of the two laser pulses. To analyze the flight time difference between the two laser pulses, it is necessary to align the time axis starting points of the two detections based on the emission time of the two laser pulses and then analyze the position of the rising edge of the echo signal on the time axis. The detection and sampling results of the two laser pulse echo signals after the time axis start points are aligned (Figure 1(b)) show that the rising edges of the level signals corresponding to the two laser pulse echo signals are different, but the sampling results corresponding to Laser Pulse 1 and Laser Pulse 2 are the same. In other words, a single detector alone cannot accurately distinguish the flight time differences between the different laser pulse echo signals caused by the motion of the target object.

[0067] By closely arranging several detectors, a detector array can be formed. In this case, each element in the detector array can independently respond to photons striking its photosensitive surface. This allows the detector array to detect optical signal intensity, providing information about the relationship between the moment of detection and the intensity of the optical signal. As shown in Figure 2, taking a sampling signal frequency of 1 GHz and a detector array comprising detectors 1, 2, and N as an example, for the echo signal of a laser pulse, the level signals detected by detectors 1, 2, and N can be sampled and accumulated through a logic circuit to obtain digitized histogram information. Thus, when the time-of-flight difference between the echo signals of two laser pulses is less than one clock cycle (e.g., 1 ns), although this time-of-flight difference cannot be distinguished by a single detector, the histograms corresponding to the two laser pulses will statistically exhibit a characteristic value difference. This characteristic value difference can be used to determine the time-of-flight difference between the two laser pulses, as shown in Figure 3. In other words, the radial displacement of a target within a single frame can be determined from the laser signal. Furthermore, the radial velocity of the target can be determined from the signal.

[0068] Based on the above principles, the embodiments of the present application provide a velocity measurement method, device, and laser radar system. The laser radar can emit multiple laser pulses (or detection light signals) in a single frame. After the laser pulses are reflected by the detected target, a laser pulse echo signal (or scattered light signal) is generated. The detector array of the laser radar sequentially collects the laser pulse echo signals corresponding to the multiple laser pulses, and processes each laser pulse echo signal to obtain its sampling information. Based on the sampling information of each laser pulse echo signal, the flight time difference between any two laser pulses can be determined, thereby determining the radial velocity of the detected target based on the flight time difference between the above two laser pulses and the emission time interval. In other words, the radial velocity of the detected target can be determined by a single frame of laser signal, which helps to quickly and accurately obtain the radial velocity of the detected target.

[0069] The technical solution provided by the embodiment of the present application is described in detail below with reference to Figures 4 to 13.

[0070] Figure 4 shows a schematic block diagram of a speed measurement system provided in an embodiment of the present application. As shown in Figure 4, the speed measurement system includes a laser emitting module, a laser receiving module and a data processing module, wherein the laser emitting module includes an emitting optical system, a sequence control module and a laser (not shown in the figure); the laser receiving module includes a receiving optical system and a detection module; the data processing module includes a sampling module, a micro-displacement solution module and a speed calculation module.

[0071] Specifically, the sequence control module drives the laser to emit laser pulses. The sequence control module controls the interval between multiple laser pulses, the direction in which the laser pulses are sent, and the number of laser pulses. The laser pulses generated by the laser are transmitted to the target through the transmitting optical system. Each laser pulse is reflected by the target and generates a laser pulse echo signal. The detection module receives the laser pulse echo signal through the receiving optical system and converts it into a level signal, which is input into the sampling module.

[0072] It should be noted that the detection module may include multiple SPAD detectors, each of which outputs a level signal based on the laser pulse echo signal, and multiple SPAD detectors output multiple level signals based on the same laser pulse echo signal. The sampling module samples the multiple level signals separately to obtain sampling results. The sampling result of each level signal in the multiple level signals is input into the micro-displacement solution module. The micro-displacement solution module can determine the sampling information of the laser pulse echo signal based on the sampling results of the multiple level signals associated with the same laser pulse echo. The sampling information indicates the relationship between the flight time of the optical signal and the intensity of the optical signal, and can indicate the statistical distribution of the flight time of the laser pulse. It can be understood that sampling the results of multiple SPAD detectors detecting a laser pulse echo signal obtains the relationship between the incident time of the optical signal and the intensity of the optical signal. However, based on the emission time and the incident time of the optical signal, the flight time of the optical signal can be determined, and then based on the relationship between the incident time of the optical signal and the intensity of the optical signal, the relationship between the flight time of the optical signal and the intensity of the optical signal can be obtained.

[0073] The sequence control module can drive the laser to send a sequence of laser pulses at a certain angle (or field of view), that is, a single-frame laser signal includes multiple laser pulses. In this way, the micro-displacement solution module can determine the sampling information of the multiple laser pulse echo signals corresponding to the single-frame laser signal. For example, the sampling information can be represented by a histogram, where the abscissa of the histogram is the flight time of the photon, and the ordinate of the histogram is the number of SPAD detectors that detect photons in each sampling period. This number can indicate the optical signal intensity of the laser pulse echo. If the detected target experiences radial displacement during the process of the laser emitting two laser pulses, the flight time of the echo signals corresponding to the two laser pulses will be slightly offset. This slight offset will be reflected in the histogram and will cause the characteristic values ​​of the histograms corresponding to the two laser pulse echo signals to differ, such as causing the peak value, center of gravity, and half-peak value of the histogram to shift. Furthermore, the micro-displacement solution module can determine the flight time difference between the two laser pulses based on the difference in the characteristic values ​​between the two histograms, and input the flight time difference into the velocity calculation module. For example, the micro-displacement solution module can use the peak value offset as the flight time difference. Furthermore, the velocity calculation module determines the velocity of the detected target based on the time interval of the laser pulses input by the sequence control module and the flight time difference input by the micro-displacement solution module. Taking the transmission interval of any two laser pulses in the multiple laser pulses as T as an example, if the peak offset between the histograms corresponding to the two laser pulses is Δt, the radial velocity v of the detected target can be determined according to the following formula (1):

[0074] v = Δt * c / (2*T), (1)

[0075] Where c is the speed of light and “*” represents multiplication.

[0076] In some implementations, the speed measurement system may employ a rolling shutter exposure mode, a solid-state flash exposure mode, or other exposure modes. Furthermore, the method by which the micro-displacement solving module determines the time-of-flight difference between two laser pulses based on the histogram may include a super-resolution feature recognition algorithm such as a matched filter method, a centroid method, a differential method, or a singular value decomposition (SVD).

[0077] It should be understood that the architecture of the speed measurement system shown in FIG4 is only for illustrative purposes, and the embodiments of the present application do not limit the specific structure of the speed measurement system. For example, the laser emitting module in FIG4 can be coupled with the laser receiving module, or the laser emitting module can be coaxially arranged with the laser receiving module. For another example, the sampling module in the data processing module can also be arranged in the laser receiving module. In actual applications, the modules in the above system may be added or deleted according to actual needs. For example, the system architecture shown in FIG4 can also include a scanning module, and the scanning module includes optical components for controlling the scanning direction and angle of the laser beam, such as the scanning module can include a galvanometer, a swing mirror, a rotating mirror, etc.

[0078] Based on the system shown in Figure 4, the present embodiment provides a speed measurement method. Figure 5 shows a schematic flow chart of the speed measurement method provided in the present embodiment. The method 500 can be executed by the data processing module shown in Figure 4, and includes S501 to S504.

[0079] S501 : Acquire sampling information of each of at least two echo signals and a transmission time interval of a detection light signal corresponding to the at least two echo signals, wherein the detection light signals corresponding to the at least two echo signals belong to the same frame.

[0080] Exemplarily, the sampling information may include the sampling information in the above embodiment, and the sampling information may be acquired from a sampling module.

[0081] Exemplarily, the emission time interval of the detection light signals corresponding to the at least two echo signals may be acquired from the sequence control module.

[0082] S502: Determine the flight time corresponding to each echo signal according to sampling information of each echo signal.

[0083] In some implementations, the detector detects the level signal output by each echo signal in real time, and the sampling result obtained based on the real-time level signal is also real time. That is, the sampling information of each echo signal is the relationship between the incident time of the optical signal and the intensity of the optical signal. Determining the flight time corresponding to each echo signal based on the sampling information of each echo signal may include: determining the flight time corresponding to each echo signal based on the emission time of the detection light signal corresponding to each echo signal and the time when the echo signal entered the detector as indicated by the sampling information of each echo signal. Taking the sampling information of the echo signal as a histogram indicating the relationship between the time when a photon entered the detector and the intensity of the optical signal as an example, determining the flight time corresponding to each echo signal based on the sampling information of each echo signal may include: obtaining a histogram representing the relationship between the flight time of the optical signal and the intensity of the optical signal based on the emission time of the detection light signal corresponding to each echo signal and a histogram representing the incident time of the optical signal and the intensity of the optical signal.

[0084] In some further implementations, the detector detects the level signal output by each echo signal in real time. Based on the emission time of the detection light signals corresponding to the at least two echo signals, the time axis starting points of the level signals corresponding to the at least two echo signals are aligned, i.e., the time axis starting points of the at least two detections are aligned. The level signal with the aligned time axis starting points is then sampled to obtain a sampling result. The sampling result is the position of the rising edge of the level signal on the time axis, which can indicate the flight time of a photon corresponding to the level signal. The sampling results of multiple level signals corresponding to the same echo signal are superimposed to obtain sampling information for the echo signal. In this case, the sampling information for the echo signal is the relationship between the flight time of the light signal and the intensity of the light signal.

[0085] S503: Determine the flight time difference according to the flight time corresponding to each echo signal.

[0086] Exemplarily, the flight time difference may be the flight time difference between any two echo signals of the at least two echo signals; or, the flight time difference may also be the average flight time difference. For example, if the detection light signals corresponding to the at least two echo signals include detection light signals 1 to detection light signals N, then the average flight time difference may be Δt 1，m , △t 2，m+1 , △t 3，m+2 ...and △t m-1，N Alternatively, the average flight time difference can be △t 1，2 , △t 2，3 , △t 3，4 ...and △t N-1，N The average value. Where m = N / 2, N is a positive integer, △t a，bRepresents the flight time difference between the detection light signal a and the detection light signal b.

[0087] For example, taking the sampling information as represented by a histogram indicating the relationship between the photon flight time and the light signal intensity, the histograms corresponding to any two echo signals can be processed by a super-resolution feature recognition algorithm to obtain the flight time difference between the two echo signals.

[0088] In some implementations, the method of determining the flight time difference corresponding to any two echo signals according to the sampling information of the two echo signals can be described in the above embodiments and will not be repeated here.

[0089] S504: Determine the radial velocity of the target according to the emission time interval and the flight time difference.

[0090] For example, the radial velocity of the target is determined based on the flight time difference and the emission time interval corresponding to the flight time difference. The emission time interval corresponding to the flight time difference can be understood as: the emission time interval between the detection light signals of two echo signals associated with the flight time difference. For example, if the flight time difference is the flight time difference associated with any two echo signals, then the emission time interval is the emission time interval between the detection light signals corresponding to the above two echo signals. For another example, when the flight time difference is the average flight time difference, if the average flight time difference is Δt 1，m , △t 2，m+1 , △t 3，m+2 ...and △t m-1，N The average value of , the transmission time interval is the transmission time interval between the detection light signal 1 and the detection light signal m.

[0091] In some implementations, determining the radial velocity of the target based on the emission time interval and the flight time difference includes: determining the displacement of the target corresponding to the flight time difference based on the emission time interval; and determining the radial velocity based on the displacement and the flight time difference.

[0092] The displacement of the target corresponding to the flight time difference can be understood as the radial distance moved by the target within the flight time difference.

[0093] For example, the displacement of the target is obtained by multiplying the emission time interval by the speed of light, and the radial velocity of the target is obtained by the ratio of the displacement to the flight time difference. For example, the radial velocity of the target can be determined according to the above formula (1).

[0094] The speed measurement method provided in the embodiment of the present application can determine the radial velocity of the target through a single-frame laser signal, which helps to improve the speed measurement efficiency and accuracy, and in particular, can improve the measurement capability of low-speed targets.

[0095] During current sampling, when the rising edges of the level signals associated with the two laser pulse echo signals both fall within a sampling period, the sampling circuit in the sampling module may not be able to distinguish the time difference between the rising edges of the two level signals. For example, as shown in (b) in FIG1 , the rising edge of the level signal associated with the echo signal of laser pulse 1 (hereinafter referred to as level signal 1) and the rising edge of the level signal associated with the echo signal of laser pulse 2 (hereinafter referred to as level signal 2) both arrive after the rising edge of the first sampling signal. However, the sampling mechanism of the trigger enables the sampling module to identify the rising edges of level signal 1 and level signal 2 only when the rising edge of the second sampling signal arrives, ultimately resulting in the inability to distinguish the time difference between the rising edges of level signal 1 and level signal 2 from the sampling results. It should be understood that the above-mentioned time difference indicates the flight time difference between the two laser pulses.

[0096] It should be noted that the level signal associated with the laser pulse echo signal refers to the level signal output by the detector when detecting the laser pulse echo signal.

[0097] In some implementations, in order to improve the sampling module's ability to identify tiny flight time differences between two laser pulses, an embodiment of the present application adds a setup and hold adjustment module (as shown in FIG6 ) to the system shown in FIG1 , and the setup and hold adjustment module is used to adjust the setup time and / or hold time of the sampling signal.

[0098] Exemplarily, the bottom layer of the sampling module is a trigger, for example, a D-type trigger as shown in Figure 7. The D terminal is connected to the input level signal, the Q terminal is the sampled output, and the entire sampling process is controlled by an external clock clk.

[0099] When clk is low, transmission gates T1 and T4 are turned on, while transmission gates T2 and T3 are turned off. The voltage level signal at terminal D is transmitted to the input of T3, and the portion from the output of T3 to the Q terminal forms a latch, keeping the output of terminal Q unchanged. When clk is high, transmission gates T1 and T4 are turned off, while T2 and T3 are turned on. A latch is formed between the output of T1 and T3, keeping the voltage level unchanged. The signal at the input of T3 is transmitted to the output of T3, and because T4 is turned off, the voltage level signal is transmitted to the Q terminal. In other words, before clk jumps from low to high, sufficient time must be left for the voltage level signal to pass from terminal D to the input of T3. During this period, the voltage level signal at terminal D must remain stable, which is called the setup time. After clk jumps to high, it takes a certain amount of time for the transmission gate to shut down, and during this period, the voltage level signal at terminal D must continue to remain stable, which is called the hold time.

[0100] Both setup time and hold time are time ranges constrained forward or backward based on the rising edge of the sampling signal (or clock transition edge). During this period, the voltage level is not fully established, which can be called a metastable period. If the voltage level of the D-terminal input changes during this period, metastable sampling may occur. That is, if sampling is performed during this period, there is a certain probability that the sampling result will be inconsistent with the actual input signal. Furthermore, the closer the point of change in the voltage level of the D-terminal input is to the clock transition edge, the greater the probability of sampling error. As shown in Figure 8, the probability of sampling error near the clock transition edge is close to 100%, and the probability of sampling error gradually decreases as it moves away from the clock transition edge.

[0101] When the level signal associated with the laser pulse echo signal falls into the metastable interval of a certain sampling period, there is a certain probability that the rising edge of the level signal will be recognized by the sampling module in the sampling period, but there is a certain probability of sampling error. Therefore, under the current technical background, in order to ensure the accuracy of the sampling result, metastable sampling is generally avoided during actual sampling. Therefore, the setup time and hold time are set to be relatively small, reducing the probability that the rising edge of the level signal associated with the laser pulse echo signal falls into the metastable sampling interval. In this way, when the rising edges of the level signals associated with the two laser pulse echo signals both fall into a sampling period, and when the two rising edges of the level signals are both far away from the metastable interval, the sampling circuit cannot distinguish the time difference between the two level signals, as shown in (a) in Figure 9.

[0102] In order to improve the discrimination of the time difference between the rising edges of the two level signals associated with the laser pulse echo signal in the final sampling result, the embodiment of the present application increases the setup time and / or hold time of the sampling circuit so that the sum of the setup time and hold time is greater than or equal to one sampling period. For example, as shown in (b) in Figure 9, the rising edge of level signal 1 falls into the metastable interval of the first sampling period and has a probability of being identified in the first sampling period, while the rising edge of level signal 2 falls into the metastable interval of the second sampling period, so that level signal 2 can be identified in the second sampling period. In this way, the sampling result can show the difference between the rising edge of level signal 1 and the rising edge of level signal 2.

[0103] It can be understood that since the echo signal of each laser pulse contains multiple photons, a probabilistic statistical effect can be achieved. Therefore, increasing the setup time and / or hold time can improve the sampling module's ability to identify the rising edge of the level signal associated with the laser pulse echo signal, thereby more accurately distinguishing the slight time difference between the rising edges of the level signals associated with two laser pulse echo signals.

[0104] In a specific implementation, the setup / hold time can be adjusted by changing the length of the gate-level circuit delay chain in the trigger, for example, by increasing the length of the gate-level circuit delay chain to increase the setup time and / or hold time, or by changing the gate-level circuit power supply voltage to adjust the setup / hold time, or by other methods.

[0105] In some implementations, in order to improve the sampling module's ability to identify the small flight time difference between two laser pulses, the embodiment of the present application adds a signal edge adjustment module (as shown in Figure 10) to the system shown in Figure 1. The signal edge adjustment module is arranged between the detection module and the sampling module, and is used to filter the level signal output by the detection module to slow down the transition edge slope of the level signal output by the detection module, as shown in Figure 11. It can be understood that after slowing down the transition edge slope of the level signal, the time between the intensity of the level signal being greater than the low level threshold and less than the high level threshold becomes longer, wherein, when the intensity of the level signal is less than or equal to the low level threshold, the sampling module will not identify the level signal as a high level; when the intensity of the level signal is greater than or equal to the high level threshold, the sampling module can accurately identify the level signal as a high level; when the intensity of the level signal is greater than the low level threshold and less than the high level threshold, the sampling module has a certain probability of identifying the level signal as a high level. Therefore, slowing down the transition edge slope of the level signal can be equivalent to increasing the setup / hold time. For example, as shown in (a) of FIG12 , before filtering the level signal output by the detection module, the rising edge of level signal 1 and the rising edge of level signal 2 both arrive after the rising edge of the first sampling signal, so that the sampling circuit can only identify the rising edge of level signal 1 and the rising edge of level signal 2 when the rising edge of the second sampling signal arrives, ultimately resulting in the inability to distinguish the time difference between the rising edge of level signal 1 and the rising edge of level signal 2 from the sampling result. After slowing down the slope of the level signal transition edge, when the first clock rising edge arrives, level signal 1 has reached a certain signal strength, making it possible for level signal 1 to be identified in the first clock cycle. In this way, the sampling result can present the difference between the rising edge of level signal 1 and the rising edge of level signal 2.

[0106] In some implementations, a signal edge adjustment module and a setup and hold adjustment module may be added to the system shown in FIG1 to improve the sampling module's ability to identify small flight time differences between laser pulses.

[0107] In some implementations, before transmitting the detection light signals corresponding to the at least two echo signals, the method further includes: determining, based on the distance between the target and the laser radar system, the transmission time of the detection light signals corresponding to the at least two echo signals. Exemplarily, the transmission time of the first laser signal is determined so that the rising edges of the level signals associated with the first few echo signals of the at least two echo signals fall within a metastable interval of a certain sampling cycle. If the target undergoes displacement changes during the transmission of the detection light signals associated with the at least two echo signals, the rising edges of the level signals associated with some of the at least two echo signals may fall outside the metastable interval of the sampling cycle. For example, as shown in FIG13 , the transmission time of the detection light signals corresponding to the at least two echo signals is determined so that the rising edge of level signal 1 falls within the metastable interval of the first sampling cycle. If the target moves between the transmission time intervals of laser signal 1 and laser signal 2, the position of the rising edge of level signal 2 within the metastable interval will change, and may even cause the rising edge of level signal 2 to fall outside the metastable interval of the first clock cycle. In this way, the sampling result can present the difference between the rising edge of the level signal 1 and the rising edge of the level signal 2.

[0108] Exemplarily, the distance between a target and a lidar system can be determined based on the flight times of other probe light signals belonging to the same frame as the probe light signals corresponding to at least two echo signals. These other probe light signals can be the first several probe light signals in a frame of probe light signals, and the probe light signals corresponding to the at least two echo signals are emitted after these first several probe light signals. More specifically, the distance is determined based on the flight times of the first several probe light signals in a group of probe light signals for the same target. The emission times of subsequent probe light signals in the group are then adjusted based on the distance so that the rising edges of the level signals associated with the echo signals of the first several probe light signals in the subsequent several probe light signals fall within a metastable interval.

[0109] It should be noted that the laser pulse 1 and the laser pulse 2 shown in Figures 9, 12 and 13 can be any two detection light signals of the detection light signals associated with at least two echo signals, and the level signal 1 associated with the echo signal of the laser pulse 1 and the level signal 2 associated with the echo signal of the laser pulse 2 shown in Figures 9, 12 and 13 have been normalized in the time dimension, that is, the laser pulse 1 and the laser pulse 2 have been regarded as laser pulses sent at the same time.

[0110] It should also be noted that in actual implementation, the detection module can also be implemented by combining a time-to-digital converter (TDC) with a silicon photomultiplier (SiPM), an analog digital converter (ADC), or a SPAD detector. The TDC can accurately measure the exact moment of the input signal through a circuit delay chain, with an accuracy of up to 10 ps. Furthermore, with the advancement of semiconductor technology, the accuracy of TDC-based measurements can continue to improve. Therefore, based on the TDC, it is possible to accurately measure the return time of each laser pulse in multiple laser pulses, and to distinguish the time-of-flight difference between any two laser pulses within a single-frame laser signal.

[0111] The method provided in the embodiments of the present application is described in detail above with reference to Figures 2 to 13. The apparatus provided in the embodiments of the present application will be described in detail below with reference to Figures 14 and 15. The description of the apparatus embodiment corresponds to the description of the method embodiment. Therefore, any content not described in detail can be referred to the method embodiment above.

[0112] For example, FIG14 shows a schematic block diagram of a speed measurement device provided in an embodiment of the present application. The device 1000 may include a control unit 1010 and a processing unit 1020. For example, the device 1000 may be a laser radar, or may be a chip or processor in the laser radar, or may be a terminal (such as a computing platform) in an intelligent driving device for signal processing or control of the laser radar, or a chip or processor in the terminal, or may be a chip or processor in a control device corresponding to the laser radar, etc.

[0113] The apparatus 1000 may include a unit for executing the above method 500 , and each unit in the apparatus 1000 may be used to execute a corresponding process in the above method 500 .

[0114] When the device 1000 is used to execute the method 500 , the acquiring unit 1010 may be used to execute S501 in the method 500 , and the processing unit 1020 may be used to execute steps S502 to S504 in the method 500 .

[0115] Specifically, the acquisition unit 1010 is configured to obtain sampling information for each of at least two echo signals and a transmission time interval of the probe light signals corresponding to the at least two echo signals, wherein the probe light signals corresponding to the at least two echo signals belong to the same frame. The processing unit 1020 is configured to determine the flight time corresponding to each echo signal based on the sampling information of each echo signal; determine the flight time difference based on the flight time corresponding to each echo signal; and determine the radial velocity of the target based on the transmission time interval and the flight time difference.

[0116] In some implementations, the processing unit 1020 is configured to: determine a displacement of the target corresponding to the flight time difference based on the transmission time interval; and determine a radial velocity based on the displacement and the flight time difference.

[0117] In some implementations, the sampling information includes superposition information output by multiple sampling points.

[0118] In some implementations, a sum of a setup time and a hold time of a sampling circuit at each of the plurality of sampling points is greater than or equal to one sampling period.

[0119] In some implementations, the setup time and / or the hold time are adjusted based on environmental information.

[0120] In some implementations, the sampling information of one echo signal among at least two echo signals is obtained by sampling the level signal corresponding to the echo signal, and the processing unit 1020 is further used to: filter the level signal before sampling the level signal, and the filtering process is used to slow down the transition edge slope of the level signal.

[0121] In some implementations, the device is disposed in a laser radar system, and the emission time of the detection light signal corresponding to at least two echo signals is determined based on the distance between the target and the laser radar system.

[0122] The division of the various units in the above devices is merely a division of logical functions. In actual implementation, they may be fully or partially integrated into a single physical entity, or physically separated. All units in the above devices may be implemented entirely through a processor calling software, entirely through hardware circuits, or partially through a processor calling software, with the remainder implemented through hardware circuits.

[0123] In a specific implementation, the acquisition unit 1010 may be implemented by at least one transceiver or transceiver-related circuits, and the processing unit 1020 may be implemented by at least one processor or processor-related circuits. For example, in a specific implementation, the apparatus 1000 may be a data processing module in the speed measurement system shown in FIG. 4 , FIG. 6 , or FIG. 10 . Alternatively, the apparatus 1000 may be a chip or processor disposed in the speed measurement system shown in FIG. 4 , FIG. 6 , or FIG. 10 .

[0124] For example, Figure 15 is another schematic block diagram of a speed measurement device provided in an embodiment of the present application. The device 2000 may include a processor 2010, a transceiver 2020, and a memory 2030. The processor 2010, transceiver 2020, and memory 2030 are connected via an internal connection path. The memory 2030 is used to store instructions, and the processor 2010 is used to execute the instructions stored in the memory 2030, receiving and transmitting certain parameters through the transceiver 2020. Optionally, the memory 2030 may be coupled to the processor 2010 via an interface or may be integrated with the processor 2010.

[0125] It should be noted that the transceiver 2020 may include, but is not limited to, a transceiver device such as an input / output interface to enable communication between the device 2000 and other devices or communication networks. For example, communication may be performed between the transceiver 2020 and a laser emitting module and / or a laser receiving module.

[0126] An embodiment of the present application also provides a laser radar system, which includes a laser transmitting module, a laser receiving module, and the above-mentioned device 1000 or device 2000.

[0127] An embodiment of the present application further provides an intelligent driving device, which includes the speed measuring device 1000 or the speed measuring device 2000 in the above embodiment; or, the intelligent driving device includes the laser radar system in the above embodiment.

[0128] The intelligent driving device involved in the embodiments of the present application can be a vehicle in a broad sense, which can be a means of transportation (such as commercial vehicles, passenger cars, motorcycles, flying cars, trains, etc.), industrial vehicles (such as forklifts, trailers, tractors, etc.), engineering vehicles (such as excavators, bulldozers, cranes, etc.), agricultural equipment (such as mowers, harvesters, etc.), amusement equipment, toy vehicles, etc. The embodiments of the present application do not specifically limit the type of vehicle.

[0129] An embodiment of the present application further provides a computer program product, which includes: computer program code, which, when executed on a computer, enables the computer to execute the method in the above embodiment and any possible implementation thereof.

[0130] An embodiment of the present application also provides a computer-readable storage medium, which stores program code or instructions. When the computer program code or instructions are executed by a computer processor, the processor implements the method in the above embodiment and any possible implementation method thereof.

[0131] An embodiment of the present application also provides a chip, including a circuit, for executing the method in the above embodiment and any possible implementation thereof.

[0132] In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is a kind of association relationship that describes associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In this application, "at least one" refers to one or more, and "more than one" refers to two or more. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0133] In the embodiments of this application, prefixes such as "first" and "second" are used only to distinguish different description objects and have no limiting effect on the position, order, priority, quantity, or content of the described objects. The use of prefixes such as ordinal numbers in the embodiments of this application to distinguish description objects does not constitute a limitation on the described objects. For a statement of the described objects, please refer to the description in the context of the claims or embodiments, and the use of such prefixes should not constitute an unnecessary limitation.

[0134] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0135] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes and beneficial effects of the above-described systems, devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0136] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0137] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0138] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0139] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0140] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A speed measurement method, characterized in that: include: Acquiring sampling information of each of at least two echo signals and a transmission time interval of a detection light signal corresponding to the at least two echo signals, wherein the detection light signals corresponding to the at least two echo signals belong to the same frame; Determining the flight time corresponding to each echo signal according to the sampling information of each echo signal; Determine the flight time difference according to the flight time corresponding to each echo signal; The radial velocity of the target is determined according to the emission time interval and the flight time difference.

2. The method according to claim 1, characterized in that Determining the radial velocity of the target according to the emission time interval and the flight time difference includes: determining, based on the emission time interval, a displacement of the target corresponding to the flight time difference; The radial velocity is determined based on the displacement and the time-of-flight difference.

3. The method according to claim 1 or 2, characterized in that The sampling information includes superposition information output by multiple sampling points.

4. The method according to claim 3, characterized in that The sum of the setup time and the hold time of the sampling circuit of each sampling point among the multiple sampling points is greater than or equal to one sampling period.

5. The method according to claim 4, characterized in that The establishment time and / or the holding time are adjusted according to environmental information.

6. The method according to any one of claims 1 to 5, characterized in that The sampling information of one echo signal among the at least two echo signals is obtained by sampling a level signal corresponding to the echo signal, and the method further includes: Before sampling the level signal, filtering is performed on the level signal, and the filtering is used to slow down the transition edge slope of the level signal.

7. The method according to any one of claims 1 to 6, characterized in that The method is executed by a laser radar system, and further comprises: determining, based on the distance between the target and the laser radar system, the emission time of the detection light signal corresponding to at least two echo signals.

8. A speed measuring device, characterized in that: It includes an acquisition unit and a processing unit, wherein: The acquisition unit is used to: acquire sampling information of each echo signal of at least two echo signals and a transmission time interval of the detection light signals corresponding to the at least two echo signals, wherein the detection light signals corresponding to the at least two echo signals belong to the same frame; The processing unit is configured to: Determining the flight time corresponding to each echo signal according to the sampling information of each echo signal; Determining a flight time difference according to the flight time corresponding to each echo signal; and The radial velocity of the target is determined according to the emission time interval and the flight time difference.

9. The device according to claim 8, characterized in that The processing unit is used for: determining, based on the emission time interval, a displacement of the target corresponding to the flight time difference; The radial velocity is determined based on the displacement and the time-of-flight difference.

10. The device according to claim 8 or 9, characterized in that The sampling information includes superposition information output by multiple sampling points.

11. The device according to claim 10, characterized in that The sum of the setup time and the hold time of the sampling circuit of each sampling point among the multiple sampling points is greater than or equal to one sampling period.

12. The device according to claim 11, characterized in that The establishment time and / or the holding time are adjusted according to environmental information.

13. The device according to any one of claims 8 to 12, characterized in that The sampling information of one echo signal among the at least two echo signals is obtained by sampling a level signal corresponding to the echo signal, and the processing unit is further configured to: Before sampling the level signal, filtering is performed on the level signal, and the filtering is used to slow down the transition edge slope of the level signal.

14. The device according to any one of claims 8 to 13, characterized in that The device is arranged in a laser radar system, and the emission time of the detection light signal corresponding to the at least two echo signals is determined according to the distance between the target and the laser radar system.

15. A speed measuring device, characterized in that: include: Memory for storing computer programs; A processor, configured to execute the computer program stored in the memory, so that the apparatus performs the method according to any one of claims 1 to 7.

16. A laser radar system, characterized in that: The system includes a laser emitting module, a laser receiving module, and a device according to any one of claims 8 to 15; wherein the laser emitting module is used to emit a detection light signal corresponding to the at least two echo signals, and the laser receiving module is used to receive the at least two echo signals.

17. An intelligent driving device, characterized in that: Comprising the apparatus according to any one of claims 8 to 15, or the system according to claim 16.

18. A computer-readable storage medium, characterized in that Instructions are stored thereon, and when the instructions are executed by a processor, the processor is caused to implement the method according to any one of claims 1 to 7.

19. A computer program product, characterized in that The computer program product comprises: a computer program code, and when the computer program code is executed, the method according to any one of claims 1 to 7 is implemented.

20. A chip, characterized in that: The chip comprises a circuit for executing the method according to any one of claims 1 to 7.

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