Echo signal detection method, device, medium and laser radar

Abstract

The present disclosure relates to an echo signal detection method, device, medium and laser radar, and the echo signal detection method includes: obtaining an initial echo signal; the initial echo signal is an electrical signal generated by a photodetector in response to an echo light; attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal; based on the first target echo signal and the second target echo signal, determining the recognition time of the secondary echo signal. Thus, the attenuated first target echo signal can be used to ensure that the echo signal corresponding to the nearby object to be measured can be identified, thereby improving the nearby blind spot; at the same time, the amplified second target echo signal can be used to ensure that the distant object to be measured can be identified, thereby improving the measurement distance, and by synchronously attenuating and amplifying the initial echo signal, and selecting an appropriate signal for timing and ranging, it is beneficial to achieve the advantages of both small blind spot and long-distance measurement.

Description

Technical Field

[0001] The present disclosure relates to the field of laser detection technology, and in particular to an echo signal detection method, device, medium and laser radar. Background Art

[0002] LiDAR is an active sensor that uses laser signals of a specific wavelength (such as ranging light pulses) to scan the surface of an object to obtain relevant characteristic information of the object's surface. Compared with ordinary microwave radar, LiDAR has the advantages of high resolution, good concealment, strong anti-interference ability, small size and light weight.

[0003] At present, most laser radars use a pulsed laser as the transmitter to measure distance using the Time of Flight (TOF) method; correspondingly, the receiver uses the received echo pulse timing to achieve distance measurement. Existing laser radars cannot take into account both the distance measurement and the improvement of blind spots. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides an echo signal detection method, device, medium and laser radar.

[0005] The present disclosure provides an echo signal detection method, comprising:

[0006] Acquire an initial echo signal; the initial echo signal is an electrical signal generated by the photodetector in response to the echo light;

[0007] Attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal;

[0008] Based on the first target echo signal and the second target echo signal, a recognition time of a secondary echo signal is determined.

[0009] Optionally, determining the recognition time of the secondary echo signal based on the first target echo signal and the second target echo signal includes:

[0010] Based on the first target echo signal, identifying a first candidate identification time of the secondary echo signal;

[0011] Based on the second target echo signal, identifying a second candidate identification time of the secondary echo signal;

[0012] When at least the second candidate identification time is successfully identified, the second candidate identification time is determined as the identification time.

[0013] Optionally, the method further comprises:

[0014] When the first candidate identification time is successfully identified but the second candidate identification time is not successfully identified, the first candidate identification time is determined as the identification time.

[0015] Optionally, the method further comprises:

[0016] Acquiring a transmission time of a detection signal corresponding to the echo signal;

[0017] A target detection distance is determined based on the emission time and the recognition time.

[0018] Optionally, attenuating the initial echo signal by a first preset multiple includes: attenuating the initial echo signal by the first preset multiple using an attenuation circuit;

[0019] and / or,

[0020] Amplifying the initial echo signal by a second preset multiple includes: amplifying the initial echo signal by the second preset multiple using an amplifying circuit.

[0021] The present disclosure also provides an echo signal detection device, comprising:

[0022] An acquisition module, used for acquiring an initial echo signal;

[0023] A conversion module, configured to attenuate the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplify the initial echo signal by a second preset multiple to obtain a second target echo signal;

[0024] The identification module is used to determine the identification time of the secondary echo signal based on the first target echo signal and the second target echo signal.

[0025] The present disclosure also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a program or instruction, wherein the program or instruction enables a computer to execute the steps of any of the above methods.

[0026] The present disclosure also provides a laser radar, comprising:

[0027] a photodetector, configured to receive the echo light and generate an initial echo signal in response to the echo light;

[0028] an attenuation circuit, used for attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal;

[0029] an amplifying circuit, used for amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal;

[0030] A timing module is used to determine the recognition time of the secondary echo signal based on the first target echo signal and the second target echo signal.

[0031] Optionally, the timing module is specifically used to:

[0032] Based on the first target echo signal, identifying a first candidate identification time of the secondary echo signal;

[0033] Based on the second target echo signal, identifying a second candidate identification time of the secondary echo signal;

[0034] When at least the second candidate time is successfully identified, determining the second candidate identification time as the identification time; or,

[0035] When the first candidate identification time is successfully identified but the second candidate identification time is not successfully identified, the first candidate identification time is determined as the identification time.

[0036] Optionally, the laser radar further includes:

[0037] A transmitting system for sending out a detection signal;

[0038] The calculation module is used to calculate the target detection distance based on the emission time of the detection signal and the recognition time.

[0039] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0040] The echo signal detection method provided by the present disclosure includes obtaining an initial echo signal; the initial echo signal is an electrical signal generated by a photodetector in response to an echo light; attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal; based on the first target echo signal and the second target echo signal, determining the recognition time of the secondary echo signal. Thus, the attenuated first target echo signal can be used to ensure that the echo signal corresponding to the nearby object under test can be identified, thereby improving the nearby blind spot; at the same time, the amplified second target echo signal can be used to ensure that the distant object under test can be identified, thereby increasing the measurement distance. Thus, by synchronously attenuating and amplifying the initial echo signal, and selecting the appropriate signal therein for subsequent timing and ranging, the laser radar is advantageous in having the advantages of small blind spot and long-distance measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0043] Figure 1 A schematic diagram of the ranging principle of a laser radar according to an embodiment of the present disclosure;

[0044] Figure 2 A schematic diagram of a time variation trend of an echo signal according to an embodiment of the present disclosure;

[0045] Figure 3 Another schematic diagram of the time variation trend of an echo signal according to an embodiment of the present disclosure;

[0046] Figure 4 It is a schematic diagram of another echo signal changing over time according to an embodiment of the present disclosure;

[0047] Figure 5 A schematic diagram of a flow chart of an echo signal detection method according to an embodiment of the present disclosure;

[0048] Figure 6 This is a schematic diagram of echo signal attenuation comparison according to an embodiment of the present disclosure;

[0049] Figure 7 A schematic diagram of echo signal amplification comparison according to an embodiment of the present disclosure;

[0050] Figure 8 It is a structural schematic diagram of an echo signal detection device according to an embodiment of the present disclosure;

[0051] Fig. 9 The figure is a schematic diagram of the structure of a laser radar according to an embodiment of the present disclosure.

[0052] Fig.10 It is a schematic diagram of the structure of another laser radar according to an embodiment of the present disclosure.

[0053] Among them, 10, laser radar; 11, transmitting end; 12, receiving end; 13, timing chip; 01, target to be measured, also called "measured object" or "measured object"; X, horizontal axis, time, the physical unit can be ns; Y1 and Y2, vertical axis, Y1 represents output current (unit: A) or output voltage (unit: V), Y2 represents relative peak power (unit: 1); L01, L02, L11 and L21 correspond to the signals detected by APD respectively, L12 corresponds to the signal after attenuation of L11, L22, the signal covered by L21; 410, acquisition module; 420, conversion module; 430, identification module; 510, photodetector; 520, attenuation circuit; 530, amplification circuit; 540, timing module; 550, transmitting system; 560, calculation module. DETAILED DESCRIPTION

[0054] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0055] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0056] First, combine Figure 1 The TOF ranging principle of the laser radar provided in the embodiment of the present disclosure is exemplified. Specifically, when the pulse laser radar is used for ranging, a TOF ranging solution based on pulsed laser is usually adopted, that is: the transmitting end 11 of the laser radar 10 emits a ranging light pulse, and at the same time triggers the timing chip 13 as a START signal, and the time of this triggering moment is recorded as t0; after the light pulse is diffusely reflected by the measured target 01, the echo pulse is detected and received by the receiving end 12 of the laser radar 10, and after photoelectric conversion, it is used as a STOP signal to trigger the timing chip 13, and the time of this triggering moment is recorded as t1; in this way, the timing corresponding to one ranging is completed.

[0057] The flight time of the light pulse is: △t = t1-t0; combined with the speed of light to perform "time-distance conversion", the final distance measurement result can be obtained, that is, the detection distance is: l = △t × c / 2. Among them, c represents the speed of light in the current medium.

[0058] For the receiving end of the above-mentioned laser radar, at least one photodetector that meets the laser radar's requirements for the number of detection units is required. The photodetector can be a single-point detector, a linear array detector, or a planar array detector, such as a planar array avalanche photodiode (APD) detector, etc., and a corresponding signal processing circuit or program is designed to realize the processing of pulse signals. Among them, the advantages of APD include: insensitivity to magnetic fields, low power consumption, small size, large operating spectrum range, low operating voltage, etc.

[0059] In the application of laser radar for ranging, there will be a problem of radar blind spots. The specific manifestation of blind spots is that the laser radar cannot obtain effective ranging points at a relatively close measurement distance. Among them, the blind spots caused by different laser radar system designs are different, which will not be elaborated here. The main reasons for the "radar blind spot" are explained as follows:

[0060] First, a blind spot is created due to the response time of the APD.

[0061] Specifically, APD is a photosensitive element used in laser communication and is a specific implementation structure of a photodetector. APD is essentially a PN junction. Its principle is: after a reverse bias is applied to the PN junction of a photodiode made of silicon or germanium, the incident light is absorbed by the PN junction to form a photocurrent, that is, the APD generates an electrical signal in response to the echo light.

[0062] For example, when the receiving end receives the measured returned light signal, a current signal is generated. The stronger the returned light is, the longer the current signal lasts (e.g. Figure 2 As shown in L01, the stronger current signal lasted for nearly 90ns), and the weaker the returned light, the shorter the duration of the current information (as shown in Figure 2 As shown in L02, the weaker current signal lasted for 10ns).

[0063] When the phase difference between the secondary return optical signal (corresponding to the secondary echo signal) and the primary return optical signal (corresponding to the primary echo signal) received by the receiving end is less than the response time of the APD, the current signal of the secondary echo signal and the current signal of the primary echo signal are superimposed, resulting in the start time of the secondary echo signal being masked by the primary echo signal, so that the timing time of the secondary echo signal cannot be accurately identified, and further, the flight time of the optical pulse cannot be determined, and the corresponding distance cannot be determined, resulting in the generation of a blind spot. For example, if Figure 3 As shown in L11 in FIG. 1 , the secondary echo signal is superimposed on the primary echo signal, which makes it impossible to identify the starting point of the secondary echo signal and to time it, resulting in an inability to determine the corresponding distance, thus causing a blind spot.

[0064] In combination with the laser radar provided in the embodiment of the present disclosure, for the pulsed laser radar, its front panel will reflect back a very small part (for example 1%) of the detection signal (i.e., the emitted measurement light); but since the front panel is almost a mirror reflection and the front panel is close to the receiving end, a larger echo signal will be formed in the APD. The echo signal caused by the front panel will cover the echo signal corresponding to the measured object near the laser radar. Since the echo signal of the measured object near the laser radar is masked, a radar blind spot is caused.

[0065] In view of this, in the embodiment of the present disclosure, signal attenuation is applied to proportionally attenuate the echo signal formed by the APD, so that the time corresponding to the starting point of the secondary echo signal can be detected. Figure 3 As shown in L12, for example, the recognition time of the secondary echo signal can be detected based on the voltage threshold corresponding to the time, so as to determine the timing end time, and then the detection distance can be calculated, thereby improving the blind spot problem caused by the APD response time limitation.

[0066] Second, due to the amplifier settings, the measurement time cannot be identified, resulting in a blind spot.

[0067] Specifically, there is loss in the transmission of the measurement light in the air. As the measurement distance increases, the returned light signal gradually weakens. In order to ensure the ranging performance of the radar and improve the ranging distance of the radar, the current signal output by the APD is amplified with a fixed gain. When the current signal of the secondary echo and the current signal of the primary echo are superimposed, the secondary echo will be completely masked by the fixed gain amplification, such as Figure 4 As shown, L21 represents a large pulse width clutter signal, for example, it can be a signal obtained by amplifying the echo signal reflected by the front panel; L22 represents a signal obtained by amplifying the echo signal of a nearby measured object. L21 completely covers L22, resulting in a further increase in the radar blind area.

[0068] In view of this, the embodiment of the present disclosure combines signal attenuation. After the echo signal is attenuated, L21 has a chance to appear, so that the time corresponding to the starting point of the echo signal of the measured object can be detected, thereby determining the timing end time, and then realizing the calculation of the detection distance, improving the blind spot problem caused by the amplifier setting.

[0069] The echo signal detection method provided by the embodiment of the present disclosure is mainly used at the receiving end of a pulsed laser radar, for example, it is set in its receiving unit, and can be implemented by a hardware circuit or a software program built into a processor. Specifically, amplification and attenuation synchronization processing is set to achieve dual-path synchronous detection of the initial echo signal, thereby improving the ranging range of the laser radar; signal amplification is used to ensure that the ranging distance of the radar is large; and signal attenuation is used at the same time to improve the blind spot problem caused by the APD response time, as well as the blind spot problem caused by fixed gain amplification.

[0070] The echo signal detection method, device, medium and laser radar provided in the embodiments of the present disclosure are exemplarily described below in conjunction with the accompanying drawings.

[0071] For example, Figure 5 FIG. 1 is a flow chart of an echo signal detection method according to an embodiment of the present disclosure. Figure 5 , the method comprises the following steps:

[0072] S210: Acquire an initial echo signal.

[0073] The initial echo signal is an electrical signal generated by the photodetector in response to the echo light.

[0074] Exemplarily, at the receiving end of the laser radar, the APD receives the echo light and generates a photoelectric response to generate a corresponding electrical signal, that is, an initial echo signal; the initial echo signal is transmitted to the echo signal detection device, and correspondingly, the echo signal detection device obtains the initial echo signal; or the initial echo signal is transmitted to a subsequent processing circuit, such as an attenuation circuit or an amplification circuit, and correspondingly, the attenuation circuit and the amplification circuit obtain the initial echo signal to prepare for subsequent processing of the initial echo signal.

[0075] S220, attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal.

[0076] Among them, the initial echo signal is synchronously amplified and attenuated, such as Figure 6 and Figure 7 As shown, which will be explained in detail later, it prepares for the subsequent identification of the secondary echo signal and the determination of the identification time of the secondary echo signal.

[0077] Exemplarily, the first preset multiple may be 3 times, 5 times or other multiples, the second preset multiple may be 3 times, 5 times or other multiples, the first preset multiple and the second preset multiple may be the same or different, and may be set according to the requirements of the echo signal detection method, and is not limited here.

[0078] S230: Determine a recognition time of a secondary echo signal based on the first target echo signal and the second target echo signal.

[0079] Among them, the first target echo signal is a signal obtained by attenuating the initial echo signal by a first preset multiple, and the second target echo signal is a signal obtained by amplifying the initial echo signal by a second preset multiple. The secondary echo signal is identified based on the first target echo signal and the second target echo signal. When the secondary echo signal is identified based only on the first target echo signal, the identification time of the secondary echo signal is determined accordingly, thereby improving the influence of the front panel of the laser radar on the detection of nearby objects and improving the nearby blind spot problem of the laser radar; when the secondary echo signal can be identified based on the second target echo signal, regardless of whether the secondary echo signal can be identified based on the first target echo signal, the identification time of the secondary echo signal is determined by the second target echo signal, thereby ensuring that the laser radar can achieve a longer detection distance and ensure high detection accuracy.

[0080] The echo signal detection method provided by the embodiment of the present disclosure includes obtaining an initial echo signal; the initial echo signal is an electrical signal generated by a photodetector in response to an echo light; attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal; based on the first target echo signal and the second target echo signal, determining the recognition time of the secondary echo signal. Thus, the attenuated first target echo signal can be used to ensure that the echo signal corresponding to the nearby object under test can be identified, thereby improving the nearby blind spot; at the same time, the amplified second target echo signal can be used to ensure that the distant object under test can be identified, thereby increasing the measurement distance. Thus, by synchronously attenuating and amplifying the initial echo signal, and selecting the appropriate signal therein for subsequent timing and ranging, the laser radar is advantageous in having the advantages of small blind spot and long-distance measurement.

[0081] In some embodiments, Figure 5 Based on the S230, the S230 specifically includes:

[0082] Based on the first target echo signal, identifying a first candidate identification time of the secondary echo signal;

[0083] Based on the second target echo signal, identifying a second candidate identification time of the secondary echo signal;

[0084] When at least the second candidate time is successfully identified, the second candidate identification time is determined as the identification time.

[0085] Specifically, based on the synchronously attenuated and amplified signals, the secondary echo signals are identified respectively, and as long as the secondary echo signal can be identified based on the second target echo signal, the second alternative identification time corresponding to the secondary echo signal is used as the identification time of the secondary echo signal. Thus, the secondary echo signal is identified based on the amplified signal with high accuracy, which facilitates ensuring higher detection accuracy. At the same time, since the initial echo signal is amplified, the signal strength is higher, which can ensure detection at a longer distance.

[0086] In some embodiments, the method may further include:

[0087] When the first candidate recognition time is successfully recognized but the second candidate recognition time is not successfully recognized, the first candidate recognition time is determined as the recognition time.

[0088] Specifically, based on the synchronously attenuated and amplified signals, the secondary echo signals are identified respectively for the objects being measured near the laser radar; since the amplified signal may mask the signal of the object being measured by the front panel signal, the second alternative identification time cannot be successfully identified at this time; however, in the attenuated signal, since the falling edge of the signal on the front panel can quickly fall below the detection threshold, the first alternative identification time can be successfully identified based on the first target echo signal obtained after attenuation, and the identified first alternative identification time is used as the identification time of the secondary echo signal, thereby enabling detection of nearby objects being measured and improving the blind spot problem.

[0089] In some embodiments, the method further comprises:

[0090] Acquiring a transmission time of a detection signal corresponding to the echo signal;

[0091] Based on the launch time and recognition time, the target detection range is determined.

[0092] Specifically, in order to determine the flight time of the light pulse, it is also necessary to obtain the emission time of the detection signal. In the embodiment of the present disclosure, by obtaining the emission time of the detection signal, combined with the recognition time, and using the distance calculation formula in the above text, the target detection distance can be calculated.

[0093] In some embodiments, attenuating the initial echo signal by a first preset multiple includes: using an attenuation circuit to attenuate the initial echo signal by the first preset multiple; and / or amplifying the initial echo signal by a second preset multiple includes: using an amplification circuit to amplify the initial echo signal by the second preset multiple.

[0094] Specifically, the synchronous amplification and attenuation of the initial echo signal may be implemented by using corresponding hardware circuits.

[0095] In other implementations, a software processing program may also be used to achieve synchronous amplification and attenuation of the initial echo signal, which is not limited here.

[0096] It can be understood that the amplification and attenuation in the embodiment of the present disclosure are both performed before determining the identification time of the secondary echo signal, which means that the two are synchronized.

[0097] Based on the same inventive concept, an embodiment of the present disclosure further provides an echo signal detection device, which is used to execute the steps of any echo signal detection method provided in the above-mentioned embodiments to achieve corresponding effects.

[0098] For example, Figure 8 FIG. 1 is a schematic diagram of the structure of an echo signal detection device according to an embodiment of the present disclosure. Figure 8 The echo signal detection device includes: an acquisition module 410, used to acquire an initial echo signal; a conversion module 420, used to attenuate the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplify the initial echo signal by a second preset multiple to obtain a second target echo signal; an identification module 430, used to determine the identification time of the secondary echo signal based on the first target echo signal and the second target echo signal.

[0099] The echo signal detection device provided by the embodiment of the present disclosure can utilize the attenuated first target echo signal to ensure that the echo signal corresponding to the nearby object to be measured can be identified, thereby improving the nearby blind spot, through the synergistic effect of the above-mentioned modules; at the same time, it can utilize the amplified second target echo signal to ensure that the distant object to be measured can be identified, thereby improving the measurement distance. Therefore, by synchronously attenuating and amplifying the initial echo signal, and selecting the appropriate signal therein for subsequent timing and ranging, the laser radar is beneficial to having the advantages of small blind spot and long-distance measurement.

[0100] It is understandable that Figure 8 The echo signal detection device shown can implement any one of the echo signal detection methods in the above-mentioned embodiments and achieve corresponding effects.

[0101] Based on the above implementation, the embodiment of the present disclosure further provides a computer-readable storage medium, which stores programs or instructions. The programs or instructions enable a computer to execute the steps of any method provided in the above implementation to achieve corresponding effects.

[0102] On the basis of the above-mentioned implementation manner, the embodiment of the present disclosure further provides a laser radar, which can realize the above-mentioned detection and identification of echo signals based on a hardware circuit structure.

[0103] In the laser radar provided by the embodiment of the present disclosure, by setting the attenuation circuit and the amplification circuit to be connected to the photodetector (such as APD), dual-circuit synchronous detection of the initial echo signal output by the photodetector can be achieved, thereby improving the radar ranging range. Specifically, the attenuation circuit is used to attenuate the initial echo signal output by the APD, reduce the radar blind area distance caused by the APD response time, improve the radar blind area problem caused by the APD response time, use a fixed gain amplification circuit to ensure the ranging distance of the radar, and use dual-circuit synchronous detection to eliminate the radar blind area problem caused by the fixed gain amplification circuit.

[0104] For example, Fig. 9 FIG. 1 is a schematic diagram of the structure of a laser radar according to an embodiment of the present disclosure, showing the structure of the receiving end of the laser radar. Fig. 9 The laser radar includes: a photodetector 510, used to receive echo light and generate an initial echo signal in response to the echo light; an attenuation circuit 520, used to attenuate the initial echo signal by a first preset multiple to obtain a first target echo signal; an amplification circuit 530, used to amplify the initial echo signal by a second preset multiple to obtain a second target echo signal; a timing module 540, used to determine the recognition time of the secondary echo signal based on the first target echo signal and the second target echo signal.

[0105] Among them, the photodetector 510 may include an APD, the attenuation circuit 520 is a hardware circuit implementation form of the signal attenuation function in the conversion module 420, the amplification circuit 530 is a hardware circuit implementation form of the signal amplification function in the conversion module 420; the timing module 540 may include a timing chip.

[0106] In the disclosed embodiment, the attenuation circuit 520 attenuates the initial echo signal output by the photodetector 510, and the amplification circuit 530 amplifies the initial echo signal output by the photodetector 510. Thus, a dual-circuit synchronous detection scheme is adopted to synchronously attenuate and amplify the initial echo signal output by the photodetector 510, and the recognition time of the secondary echo signal is determined based on the attenuated and amplified signal, thereby reducing the radar blind area and improving the ranging distance of the radar.

[0107] For example, in combination Figure 6, which shows the principle of identifying the secondary echo signal in combination with the attenuated signal, wherein the dotted line represents the signal corresponding to the front panel, and the solid line represents the signal corresponding to the object being measured. Specifically, the attenuation circuit is mainly used to reduce the radar blind area. When measuring a closer object, the primary echo signal generated by the front panel of the laser radar and the secondary echo signal corresponding to the actual object being measured are superimposed; after the superimposed signal is attenuated by the attenuation circuit, the secondary echo signal and the primary echo signal can be made smaller in proportion, thereby ensuring that the falling edge of the echo signal is lower than the detection threshold as soon as possible, and then facilitating the identification of the starting time of the secondary echo signal, thereby reducing the influence of the primary echo signal on the secondary echo signal, playing a role in improving the radar blind area.

[0108] For example, in combination Figure 7 , which shows the principle of identifying the secondary echo signal in combination with the amplified signal, where the dotted line represents the signal corresponding to the front panel and the solid line represents the signal corresponding to the object to be measured. The amplifier circuit is mainly used to improve the radar ranging capability. As the transmission distance becomes longer, the intensity of the light propagating in the air is attenuated, and the intensity of the echo signal will become weaker and weaker; the initial echo signal is amplified by the amplifier circuit to ensure that the echo signal can reach the detection threshold when measuring objects at a longer distance, thereby ensuring a longer detection distance. However, the primary echo signal generated by the front panel will also be amplified, and the secondary echo signal of the nearby object (i.e., the near-end object to be measured) will be completely covered. While the radar ranging capability is improved, the radar blind area will also become larger. In view of this, when the secondary echo signal is covered in the amplified signal, the attenuated signal is used to identify the secondary echo signal, and the starting time of the identifiable secondary echo signal is used for timing, thereby improving the blind area problem caused by this.

[0109] The laser radar provided by the embodiment of the present disclosure can realize synchronous signal detection by using the attenuation circuit and the amplification circuit, so that the laser radar has the advantages of small blind area and long-distance detection. Specifically: the echo signals output by the attenuation circuit and the amplification circuit can be detected synchronously. When the object to be measured is at the response time of the APD and the blind area position introduced by setting the amplification circuit, the signal output by the attenuation circuit can detect the secondary echo signal within a fixed time, and the signal output by the attenuation circuit is used to calculate the measurement distance; when the object to be measured is greater than the blind area position introduced by the amplification circuit, only one echo signal is detected within a fixed time based on the signal output by the attenuation circuit, and the secondary echo signal can be detected within a fixed time based on the signal output by the amplification circuit. At this time, the measurement distance is calculated based on the signal output by the amplification circuit, and the full-range measurement of the laser radar is realized in summary.

[0110] In some embodiments, the timing module 540 is specifically used to:

[0111] Based on the first target echo signal, identifying a first candidate identification time of the secondary echo signal;

[0112] Based on the second target echo signal, identifying a second candidate identification time of the secondary echo signal;

[0113] When at least the second candidate time is successfully identified, determining the second candidate identification time as the identification time; or,

[0114] When the first candidate recognition time is successfully recognized but the second candidate recognition time is not successfully recognized, the first candidate recognition time is determined as the recognition time.

[0115] For example, in combination Figure 6 and Figure 7 For the near-end object to be measured, by using the attenuation circuit to attenuate the initial echo signal, a first target echo signal with a lower signal strength can be obtained, thereby exposing the starting time of the secondary echo signal corresponding to the near-end object to be measured, realizing the detection of the near-end object to be measured and improving the nearby blind spot; for the far-end object to be measured, by using the amplification circuit to amplify the initial echo signal, a second target echo signal with a stronger signal strength can be obtained, so that the rising edge of the secondary echo signal corresponding to the far-end object to be measured can reach the detection threshold, realizing the detection of the far-end object to be measured, thereby ensuring a longer detection distance.

[0116] The following describes the change of the echo signal and the distance calculation method in combination with the change process of the measured object from near to far relative to the laser radar.

[0117] When the object under test is close to the front panel of the laser radar, there is a situation where only one echo signal can be detected based on the first target echo signal and the second target echo signal. At this time, the secondary echo signal cannot be detected and the detection distance cannot be determined, indicating that the object under test is in the blind area of ​​the laser radar and the distance data is not calculated;

[0118] When the object being measured gradually moves away from the laser radar and approaches the APD response blind area, the secondary echo signal can be detected based on the first target echo signal, and only the first echo signal can be detected based on the second target echo signal. At this time, the recognition time of the secondary echo signal is detected using the first target echo signal, and the detection distance is calculated based on this;

[0119] When the object under test continues to move away from the laser radar and approaches the blind spot introduced by the amplification circuit, the secondary echo signal can be detected based on the first target echo signal, and only the first echo signal can be detected based on the second target echo signal. At this time, the recognition time of the secondary echo signal is detected by using the first target echo signal, and the detection distance is calculated based on this;

[0120] When the object under test continues to move away from the laser radar and begins to be larger than the blind area introduced by the amplification circuit, a secondary echo signal can be detected based on both the first target echo signal and the second target echo signal. At this time, the recognition time of the secondary echo signal is detected using the second target echo signal and the detection distance is calculated based on this.

[0121] When the object under test continues to move away from the laser radar and is much larger than the blind spot introduced by the amplification circuit, a secondary echo signal can be detected based on the second target echo signal, and only a single echo signal can be detected based on the first target echo signal. At this time, the recognition time of the secondary echo signal is detected using the second target echo signal, and the detection distance is calculated based on this.

[0122] When the object to be measured continues to move away from the laser radar and exceeds the ranging capability of the laser radar, only one echo signal can be detected based on the first target echo signal and the second target echo signal. At this time, the secondary echo signal cannot be detected, the detection distance cannot be determined, and the distance data is not calculated.

[0123] In some embodiments, Fig.10 FIG. 1 is a schematic diagram of the structure of another laser radar according to an embodiment of the present disclosure. Fig. 9 Based on Fig.10 The laser radar also includes: a transmitting system 550 for transmitting a detection signal; and a computing module 560 for calculating a target detection distance based on the transmitting time and the recognition time of the detection signal.

[0124] Specifically, the transmitting system 550 can emit a detection signal, which is reflected by the target to be measured to generate echo light, and the echo light is received by the APD to generate an initial echo signal accordingly; the initial echo signal is synchronously attenuated and amplified to determine the recognition time of the secondary echo signal, and further, combined with the emission time of the detection signal, the time difference is calculated using the calculation module 560 to obtain the flight time of the light pulse, and further, combined with the propagation speed of light in the current medium, the target detection distance can be calculated.

[0125] The laser radar provided in the embodiment of the present disclosure proposes a synchronous circuit detection structure for reducing blind spots, wherein the radar ranging capability is improved by a fixed gain amplifier circuit, and the radar blind spot is reduced by a signal attenuation circuit. The attenuation circuit can compensate for the blind spot introduced by the amplifier circuit and improve the blind spot introduced by the APD's own response time. The full range of the radar can be measured by a synchronous detection method, thereby improving the radar measurement range.

[0126] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0127] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting an echo signal, characterized in that: include: Acquire initial echo signal; The initial echo signal is an electrical signal generated by the photodetector in response to the echo light; Attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal; determining a recognition time of a secondary echo signal based on the first target echo signal and the second target echo signal; Wherein, the identification of the secondary echo signal based on the first target echo signal and the second target echo signal includes: when the secondary echo signal is identified based only on the first target echo signal, determining the identification time of the secondary echo signal based on the first target echo signal; when the secondary echo signal can be identified based on the second target echo signal, regardless of whether the secondary echo signal can be identified based on the first target echo signal, determining the identification time of the secondary echo signal based on the second target echo signal; The photoelectric detector is also provided with a signal amplification circuit and a signal attenuation circuit to realize dual-path synchronous detection of the initial echo signal.

2. The method according to claim 1, characterized in that The determining the recognition time of the secondary echo signal based on the first target echo signal and the second target echo signal comprises: Based on the first target echo signal, identifying a first candidate identification time of the secondary echo signal; Based on the second target echo signal, identifying a second candidate identification time of the secondary echo signal; When at least the second candidate identification time is successfully identified, the second candidate identification time is determined as the identification time.

3. The method according to claim 2, characterized in that Also includes: When the first candidate identification time is successfully identified but the second candidate identification time is not successfully identified, the first candidate identification time is determined as the identification time.

4. The method according to any one of claims 1 to 3, characterized in that: Also includes: Acquiring a transmission time of a detection signal corresponding to the echo signal; A target detection distance is determined based on the emission time and the recognition time.

5. The method according to any one of claims 1 to 3, characterized in that: Attenuating the initial echo signal by a first preset multiple, comprising: attenuating the initial echo signal by the first preset multiple using an attenuation circuit; and / or, Amplifying the initial echo signal by a second preset multiple includes: amplifying the initial echo signal by the second preset multiple using an amplifying circuit.

6. An echo signal detection device, characterized in that: include: An acquisition module, used for acquiring an initial echo signal; The initial echo signal is an electrical signal generated by the photodetector in response to the echo light; A conversion module, configured to attenuate the initial echo signal by a first preset multiple to obtain a first target echo signal; and amplify the initial echo signal by a second preset multiple to obtain a second target echo signal; an identification module, configured to determine an identification time of a secondary echo signal based on the first target echo signal and the second target echo signal; Wherein, the secondary echo signal is identified based on the first target echo signal and the second target echo signal: when the secondary echo signal is identified based only on the first target echo signal, the identification time of the secondary echo signal is determined based on the first target echo signal; when the secondary echo signal can be identified based on the second target echo signal, regardless of whether the secondary echo signal can be identified based on the first target echo signal, the identification time of the secondary echo signal is determined based on the second target echo signal; The photoelectric detector is also provided with a signal amplification circuit and a signal attenuation circuit to realize dual-path synchronous detection of the initial echo signal.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program or instruction, and the program or instruction enables a computer to execute the steps of the method according to any one of claims 1 to 4.

8. A laser radar, characterized in that: include: a photodetector, configured to receive the echo light and generate an initial echo signal in response to the echo light; an attenuation circuit, used for attenuating the initial echo signal by a first preset multiple to obtain a first target echo signal; an amplifying circuit, used for amplifying the initial echo signal by a second preset multiple to obtain a second target echo signal; a timing module, configured to determine a recognition time of a secondary echo signal based on the first target echo signal and the second target echo signal; Wherein, the secondary echo signal is identified based on the first target echo signal and the second target echo signal: when the secondary echo signal is identified based only on the first target echo signal, the identification time of the secondary echo signal is determined based on the first target echo signal; when the secondary echo signal can be identified based on the second target echo signal, regardless of whether the secondary echo signal can be identified based on the first target echo signal, the identification time of the secondary echo signal is determined based on the second target echo signal; The photoelectric detector is also provided with a signal amplification circuit and a signal attenuation circuit to realize dual-path synchronous detection of the initial echo signal.

9. The laser radar according to claim 8, characterized in that: The timing module is specifically used for: Based on the first target echo signal, identifying a first candidate identification time of the secondary echo signal; Based on the second target echo signal, identifying a second candidate identification time of the secondary echo signal; When at least the second candidate time is successfully identified, determining the second candidate identification time as the identification time; or, When the first candidate identification time is successfully identified but the second candidate identification time is not successfully identified, the first candidate identification time is determined as the identification time.

10. The laser radar according to claim 8 or 9, characterized in that: Also includes: A transmitting system for sending out a detection signal; The calculation module is used to calculate the target detection distance based on the emission time of the detection signal and the recognition time.

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