Laser radar receiving system and laser radar signal receiving method, laser radar

Abstract

The present invention relates to the field of laser radar technology, and provides a laser radar receiving system, a laser radar signal receiving method, and a laser radar. The laser radar receiving system includes a photoelectric conversion device, a first signal adjustment device, a first delay device, a switch device, a signal amplifier device, an analog-to-digital conversion device, and a control module. The photoelectric conversion device is used to receive laser pulse signals and convert them into at least two electrical signals. The output end of the photoelectric conversion device is electrically connected to the input end of the first signal adjustment device and the switch device respectively. The output end of the first signal adjustment device is electrically connected to the input end of the switch device. The switch device, the signal amplifier device, and the analog-to-digital conversion device are electrically connected in sequence. Among them, the analog-to-digital conversion device converts into a digital signal, and the control module selects a digital signal that is less than a reference non-saturation signal threshold from the digital signals at different times as an effective feedback signal, thereby improving the ranging accuracy of the laser radar and being able to adapt to different ranging scenarios.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a laser radar receiving system, a laser radar signal receiving method, and a laser radar. Background Art

[0002] Autonomous driving is gaining increasing application in the automotive sector, and the number of LiDAR systems installed in vehicles is also increasing significantly. The reliability and safety of autonomous vehicles are crucial to human safety. Consequently, LiDAR systems are required to deliver high performance, long range, and high accuracy. LiDAR utilizes the principle of laser ranging, emitting a high-power pulsed laser beam that strikes the object being measured. The time difference between the emission and reception times is used to calculate the distance.

[0003] LiDAR typically consists of a transmitter and a receiver. To improve ranging distance, the transmitter typically maintains a fixed high peak power. As peak power increases, the received signal tends to oversaturate when measuring close-range or highly reflective objects, causing signal distortion. Summary of the Invention

[0004] The purpose of the present invention is to provide a laser radar receiving system, a laser radar signal receiving method, and a laser radar, aiming to solve the technical problem that the signals received by the existing laser radar are distorted.

[0005] In a first aspect, the present application provides a laser radar receiving system, the laser radar receiving system including a photoelectric conversion device, a first signal conditioning device, a first delay device, a switch device, a signal amplifier device, an analog-to-digital converter device, and a control module, wherein the photoelectric conversion device is used to receive a laser pulse signal and convert it into at least two electrical signals, the output end of the photoelectric conversion device is electrically connected to the input end of the first signal conditioning device and the switch device, respectively, the first signal conditioning device is used to perform gain or attenuation adjustment on the electrical signal, the output end of the first signal conditioning device is electrically connected to the input end of the switch device, the switch device, the signal amplifier device, and the analog-to-digital converter device are electrically connected in sequence, and the control module is electrically connected to the signal amplifier device and the analog-to-digital converter device, respectively;

[0006] Among them, the first signal and the second signal of the at least two electrical signals are sent to the switching device and the first signal conditioning device respectively, the first delay device is used to delay the first signal or the second signal, so that the first signal and the second signal arrive at the switching device at different times, the control module is used to control the amplification factor of the signal amplifier device, and the control module is also used to compare the reference non-saturation signal threshold and the digital signals collected by the analog-to-digital converter device at different times to determine the effective feedback signal.

[0007] In one embodiment, the electrical signal output by the photoelectric conversion device is a current signal, and the laser radar receiving system further includes a first transimpedance amplifier and a second transimpedance amplifier, wherein the first transimpedance amplifier is used to convert the first electrical signal into a first voltage signal; and the second transimpedance amplifier is used to convert the second electrical signal into a second voltage signal.

[0008] In one embodiment, the first signal conditioning device is a current limiting circuit, and the current limiting circuit is connected in series between the photoelectric conversion device and the second transimpedance amplifier.

[0009] In one embodiment, the first signal conditioning device is a voltage limiting circuit, and the voltage limiting circuit is connected in series between the second transimpedance amplifier and the switching device.

[0010] In one embodiment, the first delay device is connected in series between the second transimpedance amplifier and the switch device.

[0011] In one embodiment, the control module is electrically connected to the switching device, and the control module is used to control the switching device to be in an enabled state or a disabled state at different times. When the switching device is in the disabled state, the current electrical signal is attenuated and output.

[0012] In one embodiment, the photoelectric conversion device is a photomultiplier tube or a photodiode.

[0013] In one embodiment, the signal amplifier device is used to filter, amplify, attenuate and shape the electrical signal.

[0014] In one embodiment, the laser radar receiving system includes a second signal conditioning device and a second delay device arranged in series, and there are at least three electrical signals. The third signal of the at least three electrical signals reaches the switching device through the second signal conditioning device and the second delay device.

[0015] In a second aspect, the present application provides a method for receiving a laser radar signal, the method comprising the following steps:

[0016] A photoelectric conversion device is used to receive the laser pulse signal and convert it into at least two electrical signals, wherein the at least two electrical signals include a first signal and a second signal;

[0017] Using a first signal conditioning device to perform gain or attenuation adjustment on the first signal or the second signal;

[0018] controlling the first signal and the second signal to reach the switching device at different times;

[0019] A signal amplifier is used to amplify the output signal of the switching device;

[0020] Using an analog-to-digital converter to convert the electrical signals outputted at different times by the signal amplifier into digital signals at different times;

[0021] If the digital signal at different moments is smaller than the reference non-saturation signal threshold, the digital signal at that moment is a valid feedback signal.

[0022] In one embodiment, if the digital signals at different moments are all greater than or equal to the reference non-saturation signal threshold, the amplification factor of the signal amplifier is adjusted until the digital signal at any moment is less than the reference non-saturation signal threshold.

[0023] In one embodiment, if the digital signals at different times are all smaller than the reference non-saturation signal threshold, the digital signal corresponding to the electrical signal that has not been processed by the first signal conditioning device is selected as the effective feedback signal.

[0024] In one embodiment, the switching device is controlled to be in an enabled state or a disabled state at different times. When the switching device is in the enabled state, the electrical signal at the current moment is output without attenuation. When the switching device is in the disabled state, the electrical signal at the current moment is output with attenuation.

[0025] In a third aspect, the present application provides a laser radar, which includes a laser radar transmitting system and a laser radar receiving system as described in any one of claims 1 to 7, wherein the laser radar transmitting system is used to transmit a laser pulse signal to the detected object, and the photoelectric conversion device of the laser radar receiving system is used to receive the laser pulse signal reflected back by the detected object.

[0026] The laser radar receiving system, laser radar signal receiving method, and laser radar provided by the present invention have the following beneficial effects: a photoelectric conversion device receives a laser pulse signal and converts it into at least two electrical signals, two of the at least two electrical signals are a first signal and a second signal, a first signal regulator processes one of the first signal and the second signal so that the amplitudes of the two are different, a first delay device processes one of the first signal and the second signal so that the times when the two arrive at the switching device are different, the first signal and the second signal are then amplified in turn by a signal amplifier device, and converted into digital signals by an analog-to-digital converter device, a control module selects a digital signal that is less than a reference non-saturated signal threshold from the digital signals at different times as an effective feedback signal, the effective feedback signal does not have signal saturation distortion, thereby improving the ranging accuracy of the laser radar and being able to adapt to different ranging scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic structural diagram of the laser radar receiving system provided in Example 1;

[0029] Figure 2 Schematic diagram of threshold comparison of the laser radar receiving system in the first scenario in Example 2;

[0030] Figure 3 Schematic diagram of threshold comparison of the laser radar receiving system in the second scenario in Example 2;

[0031] Figure 4 Schematic diagram of threshold comparison of the laser radar receiving system in the third scenario in Example 2;

[0032] Figure 5 Schematic diagram of threshold comparison of the laser radar receiving system in the first scenario in Example 3;

[0033] Figure 6 Schematic diagram of threshold comparison of the laser radar receiving system in the second scenario in Example 3;

[0034] Figure 7 Schematic diagram of threshold comparison of the laser radar receiving system in the third scenario in Example 3;

[0035] Figure 8 Schematic diagram of threshold comparison of the laser radar receiving system in the first scenario in the fourth embodiment;

[0036] Figure 9 Schematic diagram of threshold comparison of the laser radar receiving system in the second scenario in Example 4;

[0037] Figure 10 Schematic diagram of threshold comparison of the laser radar receiving system in the third scenario in the fourth embodiment;

[0038] Figure 11 Schematic diagram of threshold comparison of the laser radar receiving system in Example 5;

[0039] Figure 12 A schematic structural diagram of a laser radar receiving system provided in Example 6;

[0040] Figure 13A schematic structural diagram of a laser radar receiving system provided in Example 7;

[0041] Figure 14 A schematic structural diagram of a laser radar receiving system provided in Example 8;

[0042] Figure 15 A schematic structural diagram of a laser radar receiving system provided in Example 9;

[0043] Figure 16 A flow chart of the laser radar signal receiving method provided in this application.

[0044] Among them, the reference numerals in the figures are:

[0045] 10. Photoelectric conversion device; 21. First signal conditioning device; 22. Second signal conditioning device; 31. First delay device; 32. Second delay device; 41. First transimpedance amplifier; 42. Second transimpedance amplifier; 50. Switch device; 60. Signal amplification device; 70. Analog-to-digital conversion device; 80. Control module. DETAILED DESCRIPTION

[0046] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0047] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment" or "in some embodiments" appear in various places throughout this specification, not all references are to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0048] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0050] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0051] In order to meet the ranging distance, traditional lidar requires a high-peak power transmitter. When measuring close-range objects or strongly reflective objects, the received signal is easily oversaturated, causing signal distortion and affecting timing accuracy.

[0052] Example 1

[0053] Figure 1 The laser radar receiving system provided in Example 1. Figure 1 The laser radar receiving system includes a photoelectric conversion device 10, a first signal adjustment device 21, a first delay device 31, a switch device 50, a signal amplifier device 60, an analog-to-digital conversion device 70 and a control module 80.

[0054] The photoelectric conversion device 10 is used to receive the laser pulse signal and convert it into at least two electrical signals. Two of the at least two electrical signals are a first signal and a second signal. In other words, the photoelectric conversion device 10 is used to obtain the laser radar's return signal and convert it into an electrical signal for transmission and analysis. The photoelectric conversion device 10 can be a photomultiplier tube or a photodiode. For example, the photoelectric conversion device 10 is a PIN photodetector unit or an avalanche photodiode, capable of obtaining the signal returned by the laser beam, i.e., the return signal.

[0055] Among them, the electrical signal can be a current signal or a voltage signal. For example, a resistor is added to the photoelectric conversion device 10, which can convert the current signal into a voltage signal. Specifically, the electrical signal output by the photoelectric conversion device 10 is a current signal. The laser radar receiving system includes a first transimpedance amplifier 41 and a second transimpedance amplifier 42. The transimpedance amplifier is used to convert the current signal into a voltage signal, that is, the first transimpedance amplifier 41 is used to convert the first electrical signal into a first voltage signal. The second transimpedance amplifier 42 is used to convert the second electrical signal into a second voltage signal. In Figure 1In the illustrated embodiment, the first transimpedance amplifier 41 and the second transimpedance amplifier 42 can further amplify the first voltage signal and the second voltage signal, respectively, to facilitate subsequent signal transmission and processing.

[0056] The output of the photoelectric conversion device 10 is electrically connected to the inputs of the first signal conditioning device 21 and the switch device 50, respectively. The first signal conditioning device 21 is used to adjust the gain or attenuation of the electrical signal, and the output of the first signal conditioning device 21 is electrically connected to the input of the switch device 50. That is, the first and second signals of the at least two electrical signals are sent to the switch device 50 and the first signal conditioning device 21, respectively. In other words, one of the two electrical signals is amplified or attenuated by the first signal conditioning device 21 before reaching the switch device 50, while the other signal does not pass through the first signal conditioning device 21, resulting in different amplitudes for the two electrical signals.

[0057] exist Figure 1 In the illustrated embodiment, the first signal and the second signal are simultaneously output from the optoelectronic conversion device 10 and transmitted to the switching device 50. The first signal and the second signal are connected in parallel to each other. The first signal conditioning device 21 is arranged in series on the connection line of the second signal, that is, the first signal conditioning device 21 is connected in series between an output port of the optoelectronic conversion device 10 and an input port of the switching device 50. The first signal does not pass through the first signal conditioning device 21, and the second signal reaches the switching device 50 after passing through the first signal conditioning device 21.

[0058] The first delay device 31 is used to delay the first signal or the second signal so that the first signal and the second signal arrive at the switch device 50 at different times, thereby separating the two electrical signals in time. This facilitates separation and comparison with a non-saturated signal threshold, and selection of the appropriate electrical signal as the effective feedback signal. The first delay device 31 can be a first delay circuit.

[0059] exist Figure 1 In the illustrated embodiment, the first delay device 31 is connected in series to the transmission line of the second signal. The first delay device 31 is specifically connected in series between the second transimpedance amplifier 42 and the switch device 50. That is, the second signal is first converted into a voltage signal by the second transimpedance amplifier 42 and then delayed.

[0060] It will be appreciated that in some embodiments, the electrical signal output by the photoelectric conversion device 10 is a voltage signal, and the first delay device 31 can be connected in series between the photoelectric conversion device 10 and the first signal conditioning device 21. In other embodiments, the first delay device 31 is used to delay the first signal. For example, the first delay device 31 is connected in series between the switch device 50 and the first transimpedance amplifier 41.

[0061] The switch device 50, signal amplifier device 60, and analog-to-digital converter device 70 are electrically connected in sequence. The control module 80 is electrically connected to the signal amplifier device 60 and the analog-to-digital converter device 70, respectively. The signal amplifier device 60 can be a VGA amplifier module, a Darlington transistor, or a signal amplifier chip. The signal amplifier device 60 is used to receive the electrical signal output by the switch device 50 and amplify it for output. Specifically, the signal amplifier device 60 is also used to filter, attenuate, and shape the electrical signal.

[0062] The analog-to-digital converter 70 is used to receive the electrical signal output by the signal amplifier 60 and convert it into a digital signal to facilitate waveform acquisition and signal comparison processing. When the amplitude of the collected echo signal is greater than or equal to the reference non-saturation signal threshold, it indicates that the echo signal is oversaturated and distorted, and the measured distance determined based on the echo signal is inaccurate, that is, the ranging accuracy is low. When the amplitude of the collected echo signal is less than the reference non-saturation signal threshold, the echo signal is not oversaturated and distorted, which can improve the ranging accuracy. Therefore, the control module 80 is also used to compare the reference non-saturation signal threshold with the digital signals collected by the analog-to-digital converter 70 at different times to determine a valid feedback signal.

[0063] The laser radar receiving system provided in this application can provide digital signals at different times, and the amplitudes of the digital signals are different. The control module 80 selects digital signals that are less than the reference non-saturated signal threshold from the digital signals at different times as effective feedback signals, which is beneficial to improving the ranging accuracy of the laser radar and can adapt to different ranging scenarios.

[0064] The reference non-saturation signal threshold is pre-stored in the control module 80. The reference non-saturation signal threshold can be modified by personnel through programming or communication. The control module 80 performs distance calculations based on the frequency of the echo signal without requiring knowledge of the amplitude of the echo signal. The control module 80 is used to control the amplification factor of the signal amplifier 60.

[0065] In some embodiments, the gain or attenuation of the signal by the first signal conditioning device 21 is fixed and cannot be adjusted. In this case, the control module 80 may not need to be electrically connected to the first signal conditioning device 21 .

[0066] In some embodiments, the first signal conditioning device 21 is an attenuation device for attenuating the electrical signal.

[0067] In one embodiment, the combination Figure 1 The first signal conditioning device 21 is a current limiting circuit, which is connected in series between the photoelectric conversion device 10 and the second transimpedance amplifier 42. The current limiting circuit is used to attenuate the current signal to reduce the amplitude of the current signal.

[0068] In another embodiment, the first signal conditioning device 21 is a voltage limiting circuit, which is connected in series between the second transimpedance amplifier 42 and the switch device 50. In this embodiment, the current signal is first converted into a voltage signal by the second transimpedance amplifier 42 and then attenuated by the voltage limiting circuit.

[0069] If the digital signals at different times are all less than the reference non-saturated signal threshold, in some embodiments, the control module 80 adjusts the amplification factor of the signal amplifier until the digital signal at a certain time is less than the reference non-saturated signal threshold. In some embodiments, if the digital signals at two or more times are less than the reference non-saturated signal threshold, generally, the digital signal with the greater signal strength is selected for the ranging calculation, which will result in a more stable and reliable ranging result. In some embodiments, the control module 80 is electrically connected to the switching device 50, and the control module 80 is configured to control the switching device 50 to be in an enabled state or a disabled state at different times. When the switching device 50 is in the disabled state, the current electrical signal is attenuated and output until the digital signal at a certain time is less than the reference non-saturated signal threshold.

[0070] Specifically, the control module 80 sends an enable signal to the switch device 50 at a certain moment, thereby controlling the switch device 50 to be in an enabled state at that moment.

[0071] Specifically, the control module 80 sends a disable signal to the switch device 50 at a certain moment, thereby controlling the switch device 50 to be in a disabled state at that moment. Alternatively, if the switch device 50 does not receive an enable signal from the control module 80 at a certain moment, the switch device 50 is in a disabled state by default.

[0072] Example 2

[0073] Combine Figure 1 The laser radar receiving system provided in Example 2 has the same structure as any one of the laser radar receiving systems in Example 1.

[0074] In the second embodiment, the first signal reaches the switch device 50 at the first time t1, and the second signal reaches the switch device 50 at the second time t2 after passing through the first delay device 31. The second time t2 is later than the first time t1. It is understood that in other embodiments, the first time t1 is later than the second time t2.

[0075] The control module 80 is electrically connected to the switch device 50 and is configured to control the switch device 50 to be in an enabled state at both the first time t1 and the second time t2. The first and second signals are time-shared and sent to the signal amplifier 60. After amplification by the signal amplifier 60, the analog-to-digital converter 70 collects echo signals at two different times within this ranging window. The control module 80 compares the two echo signals with a reference non-saturation signal threshold to determine whether they are valid feedback signals.

[0076] Combine Figure 2 Generally, in a far-end signal ranging scenario, when the echo signal at both time t1 and time t2 is below the reference non-saturation signal threshold, the echo signal at time t1 is considered the valid feedback signal. It is understood that in other embodiments, the echo signal at time t2 is considered the valid feedback signal. In particular, in a far-end signal ranging scenario, if an object with strong reflectivity is encountered, the echo signal may become oversaturated, exceeding or equal to the reference non-saturation signal threshold.

[0077] Combine Figure 3 Generally, in mid-range ranging scenarios, if the echo signal at time t1 is greater than the reference non-saturation signal threshold and the echo signal at time t2 is less than the reference non-saturation signal threshold, the echo signal at time t2 is considered the valid feedback signal. Specifically, in mid-range ranging scenarios, if a highly reflective object is encountered, the echo signal at time t2 may also become oversaturated, exceeding or equal to the reference non-saturation signal threshold.

[0078] Combine Figure 4 In a near-end distance measurement scenario, or in a scenario encountering a strong reflectivity object (which can be a far-end, mid-end, or near-end distance measurement scenario), when the echo amplitudes at the first moment t1 and the second moment t2 are both greater than the reference non-saturation signal threshold, the control module 80 feeds back to the signal amplifier device 60 for adjustable gain attenuation until the echo signal at a certain moment is less than the reference non-saturation signal threshold; or, the control module 80 feeds back to the switch device 50, causing the switch device 50 to be in a disabled state at a certain moment, thereby attenuating the echo signal at that time, so that the echo signal at that moment is less than the reference non-saturation signal threshold.

[0079] Example 3

[0080] Combine Figure 1 The laser radar receiving system provided in Example 3 has the same structure as any one of the laser radar receiving systems in Example 1.

[0081] In the third embodiment, the first signal reaches the switch device 50 at the first time t1, and the second signal reaches the switch device 50 at the second time t2 after passing through the first delay device 31. The second time t2 is later than the first time t1. It is understood that in other embodiments, the first time t1 is later than the second time t2.

[0082] The control module 80 is electrically connected to the switch device 50 and is configured to control the switch device 50 to be enabled at a first time t1 and disabled at a second time t2. The first and second signals are time-shared and sent to the signal amplifier 60. After amplification by the signal amplifier 60, the analog-to-digital converter 70 collects echo signals at two different times within this ranging window. The control module 80 compares the two echo signals with a reference non-saturation signal threshold to determine whether they are valid feedback signals.

[0083] Combine Figure 5 Generally, in a far-end signal ranging scenario, when the echo signals at both time t1 and time t2 are below the reference non-saturation signal threshold, the echo signal at time t1 is considered a valid feedback signal. It is understood that in other embodiments, the echo signal at time t2 is considered a valid feedback signal.

[0084] Combine Figure 6 Generally, in the mid-range ranging scenario, when the echo signal at the first moment t1 is greater than the reference non-saturated signal threshold and the echo signal at the second moment t2 is less than the reference non-saturated signal threshold, the echo signal at the second moment t2 is used as the valid feedback signal.

[0085] Combine Figure 7 In a near-end distance measurement scenario, or in a scenario encountering a strong reflectivity object (which can be a far-end, mid-end, or near-end distance measurement scenario), when the echo amplitudes at the first moment t1 and the second moment t2 are both greater than the reference non-saturation signal threshold, the control module 80 feeds back to the signal amplifier device 60 for adjustable gain attenuation until the echo signal at a certain moment is less than the reference non-saturation signal threshold.

[0086] Example 4

[0087] Combine Figure 1 The laser radar receiving system provided in Example 4 has the same structure as any one of the laser radar receiving systems in Example 1.

[0088] In the fourth embodiment, the first signal reaches the switch device 50 at the first time t1, and the second signal reaches the switch device 50 at the second time t2 after passing through the first delay device 31. The second time t2 is later than the first time t1. It is understood that in other embodiments, the first time t1 is later than the second time t2.

[0089] The control module 80 is electrically connected to the switch device 50 and is configured to control the switch device 50 to be in a disabled state at a first time t1 and in an enabled state at a second time t2. The first and second signals are time-shared and enter the signal amplifier 60. After amplification by the signal amplifier 60, the analog-to-digital converter 70 collects echo signals at two different times within this ranging window. The control module 80 compares the two echo signals with a reference non-saturation signal threshold to determine whether they are valid feedback signals.

[0090] Combine Figure 8 Generally, in a far-end signal ranging scenario, when the echo signals at both time t1 and time t2 are below the reference non-saturation signal threshold, the echo signal at time t1 is considered a valid feedback signal. It is understood that in other embodiments, the echo signal at time t2 is considered a valid feedback signal.

[0091] Combine Figure 9 Generally, in the mid-range ranging scenario, when the echo signal at the first moment t1 is less than the reference non-saturated signal threshold and the echo signal at the second moment t2 is greater than the reference non-saturated signal threshold, the echo signal at the first moment t1 is used as the valid feedback signal.

[0092] Combine Figure 10 In a near-end distance measurement scenario, or in a scenario encountering a strong reflectivity object (which can be a far-end, mid-end, or near-end distance measurement scenario), when the echo amplitudes at the first moment t1 and the second moment t2 are both greater than the reference non-saturation signal threshold, the control module 80 feeds back to the signal amplifier device 60 for adjustable gain attenuation until the echo signal at a certain moment is less than the reference non-saturation signal threshold.

[0093] Example 5

[0094] Combine Figure 1 The laser radar receiving system provided in Example 5 has the same structure as any one of the laser radar receiving systems in Example 1.

[0095] In the fifth embodiment, the first signal reaches the switch device 50 at the first time t1, and the second signal reaches the switch device 50 at the second time t2 after passing through the first delay device 31. The second time t2 is later than the first time t1. It is understood that in other embodiments, the first time t1 is later than the second time t2.

[0096] The control module 80 is electrically connected to the switch device 50 and is configured to control the switch device 50 to be in a disabled state at a first time t1 and a second time t2. The first and second signals are time-shared and sent to the signal amplifier 60. After amplification by the signal amplifier 60, the analog-to-digital converter 70 collects echo signals at two different times within this ranging window. The control module 80 compares the two echo signals with a reference non-saturation signal threshold to determine whether they are valid feedback signals.

[0097] Combine Figure 11 In a near-end signal ranging scenario, or in a scenario involving a highly reflective object (which can be a far-end, mid-end, or near-end ranging scenario), when the echo signals at both the first time t1 and the second time t2 are below the reference non-saturation signal threshold, the echo signal at the first time t1 is used as the valid feedback signal. It will be appreciated that in some embodiments, the echo signal at the second time t2 is used as the valid feedback signal. In other embodiments, when both the echo signals at the first time t1 and the second time t2 are greater than or equal to the reference non-saturation signal threshold, the amplification factor of the signal amplifier 60 is adjusted until one of the echo signals at the first time t1 and the second time t2 is below the reference non-saturation signal threshold.

[0098] Of course, in the far-end signal ranging scenario and the mid-end signal ranging scenario, the echo signals at the first moment t1 and the second moment t2 are both lower than the reference non-saturated signal threshold. At this time, the echo signals at the first moment t1 and the second moment t2 are selected as valid feedback signals.

[0099] Example 6

[0100] Combine Figure 12 Compared with the laser radar receiving system in the first embodiment, the laser radar receiving system provided in the sixth embodiment eliminates the first transimpedance amplifier 41 and the second transimpedance amplifier 42. The electrical signal output by the photoelectric conversion device 10 can be a current signal or a voltage signal. When the electrical signal is a voltage signal, it does not need to be converted into a voltage signal by a transimpedance amplifier. The two electrical signals have different amplitudes and arrive at the switching device 50 and the signal amplifier device 60 at different times. After being amplified by the signal amplifier device 60, the analog-to-digital converter device 70 collects echo signals at two different times in this ranging window. The control module 80 compares the two echo signals with the reference non-saturation signal threshold to determine the effective feedback signal.

[0101] Specifically, the control module 80 is electrically connected to the switch device 50 , and the control module 80 is used to control the switch device 50 to be in an enabled state or a disabled state at different times. For details, please refer to the relevant descriptions in the second to fifth embodiments.

[0102] It can be understood that the laser radar receiving system provided in Example 6 is the same as the laser radar receiving system in Example 1 in other structures, and will not be repeated here.

[0103] Example 7

[0104] Combine Figure 13 Compared with the laser radar receiving system in Example 6, the laser radar receiving system provided in Example 7 has a different series connection order of the first delay device 31 and the first signal adjustment signal.

[0105] Specifically, in the seventh embodiment, the electrical signal output by the photoelectric conversion device 10 is a voltage signal, and the second signal first passes through the first delay device 31 and then the first signal conditioning device 21 before reaching the switch device 50 .

[0106] It can be understood that the laser radar receiving system provided in Example 7 is the same as the laser radar receiving system in Example 6 in other structures, and will not be repeated here.

[0107] Example 8

[0108] Combine Figure 14 The laser radar receiving system provided in the eighth embodiment differs from the laser radar receiving system in the seventh embodiment in that the first delay device 31 and the first signal adjustment device 21 are arranged in parallel.

[0109] Specifically, in the eighth embodiment, the first delay device 31 is used to delay the first signal, and the first signal conditioning device 21 is used to gain or attenuate the second signal. The two electrical signals, with different amplitudes, arrive at the switch device 50 and the signal amplifier device 60 at different times. After amplification by the signal amplifier device 60, the analog-to-digital converter 70 collects echo signals at two different times within the ranging window. The control module 80 compares the two echo signals with a reference non-saturation signal threshold to determine a valid feedback signal.

[0110] It can be understood that the laser radar receiving system provided in Example 8 is the same as the laser radar receiving system in Example 7 in other structures, and will not be repeated here.

[0111] Example 9

[0112] Combine Figure 15 The laser radar receiving system provided in the ninth embodiment differs from the laser radar receiving system in the first embodiment in that it has a second signal conditioning device 22 and a second delay device 32 .

[0113] Specifically, in the ninth embodiment, the lidar receiving system includes a second signal conditioning device 22 and a second delay device 32 arranged in series. There are at least three electrical signals, and the third of the at least three electrical signals reaches the switch device 50 via the second signal conditioning device 22 and the second delay device 32. Thus, the three electrical signals, with different amplitudes and time-sharing, reach the switch device 50 and the signal amplifier device 60. After amplification by the signal amplifier device 60, the analog-to-digital converter device 70 collects echo signals at three different times within this ranging window. The control module 80 compares the three echo signals with a reference non-saturation signal threshold to determine a valid feedback signal.

[0114] Specifically, the third signal may first pass through the second signal conditioning device 22 and then pass through the second delay device 32 , or may first pass through the second delay device 32 and then pass through the second signal conditioning device 22 .

[0115] Specifically, the electrical signal output by the photoelectric conversion device 10 is a voltage signal, and the second signal conditioning device 22 is a voltage limiting circuit.

[0116] It can be understood that the laser radar receiving system provided in Example 9 is the same as the laser radar receiving system in Example 1 in other structures, and will not be repeated here.

[0117] Example 10

[0118] Combine Figure 14 and Figure 16 , the present application provides a laser radar signal receiving method, comprising the following steps:

[0119] S100: Using a photoelectric conversion device 10 to receive a laser pulse signal and convert it into at least two electrical signals, the at least two electrical signals including a first signal and a second signal. Specifically, the electrical signals are current signals or voltage signals. Photoelectric conversion device 10 can be a photomultiplier tube or a photodiode. For example, photoelectric conversion device 10 can be a PIN photodetector unit or an avalanche photodiode. Photoelectric conversion device 10 is capable of splitting the echo signal into two or more paths.

[0120] S200: Using a first signal conditioning device 21, gain or attenuation is performed on the first signal or the second signal. In the illustrated embodiment, the first signal conditioning device 21 is an attenuation device, such as a current limiting circuit or a voltage limiting circuit. The first signal conditioning device 21 causes the amplitudes of the first signal and the second signal to differ.

[0121] S300: Control the first signal and the second signal to reach the switch device 50 at different times. Specifically, use the first delay device 31 to perform delay processing on the first signal or the second signal.

[0122] S400: Amplify the output signal of the switch device 50 using a signal amplifier 60. The signal amplifier 60 can be a VGA amplifier module, a Darlington transistor, or a signal amplifier chip. The signal amplifier 60 receives the electrical signal output by the switch device 50 and amplifies it for output. In some embodiments, the signal amplifier 60 also filters, attenuates, and shapes the electrical signal.

[0123] S500: using the analog-to-digital converter 70 to convert the electrical signals outputted at different times by the signal amplifier 60 into digital signals at different times.

[0124] S600: If the digital signal at different times is smaller than the reference non-saturation signal threshold, the digital signal at the time is a valid feedback signal.

[0125] When the amplitude of the collected echo signal is greater than or equal to the reference non-saturation signal threshold, it indicates that the echo signal is oversaturated and distorted, and the measured distance determined based on the echo signal is inaccurate, that is, the ranging accuracy is low. When the amplitude of the collected echo signal is less than the reference non-saturation signal threshold, the echo signal is not oversaturated and distorted, and the ranging accuracy can be improved. The above method compares the reference non-saturation signal threshold with the digital signals collected by the analog-to-digital converter 70 at different times to determine a valid feedback signal.

[0126] The method provided in this application can provide digital signals at different times, and the amplitudes of the digital signals are different, and select digital signals that are less than the reference non-saturated signal threshold from the digital signals at different times as effective feedback signals, which is beneficial to improving the ranging accuracy of the lidar and can adapt to different ranging scenarios.

[0127] In some embodiments, the above method is controlled and executed by a control module 80. The control module 80 is electrically connected to the signal amplifier 60 and the analog-to-digital converter 70. The control module 80 is configured to compare a reference non-saturation signal threshold with digital signals collected at different times by the analog-to-digital converter 70 to determine a valid feedback signal.

[0128] Specifically, the gain multiple or attenuation multiple of the signal by the first signal conditioning device 21 is fixed and cannot be adjusted. In this case, the control module 80 may not need to be electrically connected to the first signal conditioning device 21 .

[0129] Specifically, the reference non-saturation signal threshold is pre-stored in the control module 80. The reference non-saturation signal threshold can be modified by personnel through programming or communication. Based on the gain or attenuation factor of the signal applied by the first signal conditioning device 21 and the gain factor of the signal amplifier 60, the control module 80 can obtain the parameters of the original echo signal and accurately perform ranging calculations. The control module 80 is used to control the amplification factor of the signal amplifier 60.

[0130] In one embodiment, if the digital signals at different times are all greater than or equal to the reference non-saturation signal threshold, the amplification factor of the signal amplifier device 60 is adjusted until the digital signal at any time is less than the reference non-saturation signal threshold, thereby obtaining a valid feedback signal.

[0131] In one embodiment, if the digital signals at different times are all less than the reference non-saturation signal threshold, the digital signal corresponding to the electrical signal that has not been processed by the first signal conditioning device 21 is selected as the effective feedback signal. Generally, the greater the digital signal strength, the more stable and reliable the calculation result.

[0132] Specifically, combined Figure 2 The first signal, without passing through the first signal conditioning device 21, reaches the switch device 50 at a first time t1. The second signal, without passing through the first signal conditioning device 21, reaches the switch device 50 at a second time t2. In this embodiment, the first delay device 31 is used to delay the second signal, so the second time t2 is later than the first time t1. It will be appreciated that in other embodiments, the first time t1 is later than the second time t2. When the echo signals at both the first and second times t1 are below the reference non-saturation signal threshold, the echo signal at the first time t1 is considered the valid feedback signal.

[0133] In one embodiment, the control switch device 50 is in an enabled state or a disabled state at different times. When the switch device 50 is in the enabled state, the electrical signal at the current moment is output without attenuation. When the switch device 50 is in the disabled state, the electrical signal at the current moment is output with attenuation.

[0134] For example, see Example 2 and the attached Figures 2 to 4 , the switch device 50 is in the enabled state at both the first moment t1 and the second moment t2.

[0135] For example, see Example 3 and the attached Figures 5 to 7 , the switch device 50 is in an enabled state at the first moment t1 and in a disabled state at the second moment t2.

[0136] For example, see Example 4 and the attached Figures 8 to 10 , the switch device 50 is in a disabled state at the first moment t1 and in an enabled state at the second moment t2.

[0137] For example, see Example 5 and the attached Figure 11 , the switch device 50 is in a disabled state at the first moment t1 and the second moment t2.

[0138] In addition, the laser radar signal receiving method provided in Example 10 includes the structure of any one of the laser radar receiving systems in Examples 1 to 9, which will not be repeated here.

[0139] Example 11

[0140] The present application also provides a laser radar. The laser radar includes a laser radar transmitting system and a laser radar receiving system. The laser radar transmitting system is used to transmit laser pulse signals toward the detected object. The laser radar receiving system can be the structure of any of the laser radar receiving systems in Examples 1 to 9, and will not be described in detail here. In the laser radar receiving system, the photoelectric conversion device 10 is used to receive the laser pulse signal reflected from the detected object and convert it into at least two electrical signals. For example, it includes a first signal and a second signal. One of the two electrical signals is amplified or attenuated by a first signal conditioning device 21 before reaching a switching device 50. The other signal does not pass through the first signal conditioning device 21, resulting in different amplitudes of the two electrical signals. A first delay device 31 is used to delay the first signal or the second signal so that the first signal and the second signal arrive at the switching device 50 at different times. The control module 80 selects a digital signal less than a reference non-saturation signal threshold from the digital signals at different times as a valid feedback signal, which helps improve the ranging accuracy of the laser radar and adapts to different ranging scenarios.

[0141] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A laser radar receiving system, characterized in that: The laser radar receiving system includes a photoelectric conversion device, a first signal conditioning device, a first delay device, a switch device, a signal amplifier device, an analog-to-digital conversion device and a control module, wherein the photoelectric conversion device is used to receive a laser pulse signal and convert it into at least two electrical signals, the output end of the photoelectric conversion device is electrically connected to the input end of the first signal conditioning device and the switch device respectively, the first signal conditioning device is used to perform gain or attenuation adjustment on the electrical signal, the output end of the first signal conditioning device is electrically connected to the input end of the switch device, the switch device, the signal amplifier device and the analog-to-digital conversion device are electrically connected in sequence, and the control module is electrically connected to the signal amplifier device and the analog-to-digital conversion device respectively; Among them, the first signal and the second signal of the at least two electrical signals are sent to the switching device and the first signal conditioning device respectively, the first delay device is used to delay the first signal or the second signal, so that the first signal and the second signal arrive at the switching device at different times, the control module is used to control the amplification factor of the signal amplifier device, and the control module is also used to compare the reference non-saturation signal threshold and the digital signals collected by the analog-to-digital converter device at different times to determine the effective feedback signal.

2. The laser radar receiving system according to claim 1, wherein: The electrical signal output by the photoelectric conversion device is a current signal. The laser radar receiving system also includes a first transimpedance amplifier and a second transimpedance amplifier. The first transimpedance amplifier is used to convert the first signal into a first voltage signal; the second transimpedance amplifier is used to convert the second signal into a second voltage signal.

3. The laser radar receiving system according to claim 2, wherein: The first signal conditioning device is a current limiting circuit, and the current limiting circuit is connected in series between the photoelectric conversion device and the second transimpedance amplifier; And / or, the first signal conditioning device is a voltage limiting circuit, and the voltage limiting circuit is connected in series between the second transimpedance amplifier and the switching device.

4. The laser radar receiving system according to claim 2, wherein: The first delay device is connected in series between the second transimpedance amplifier and the switch device.

5. The laser radar receiving system according to claim 1, wherein: The control module is electrically connected to the switch device, and is used to control the switch device to be in an enabled state or a disabled state at different times. When the switch device is in the disabled state, the current electrical signal is attenuated and output.

6. The laser radar receiving system according to claim 1, wherein: The photoelectric conversion device is a photomultiplier tube or a photodiode; the signal amplifier device is used to filter, amplify, attenuate and shape the electrical signal.

7. The laser radar receiving system according to any one of claims 1 to 6, characterized in that: The laser radar receiving system includes a second signal regulating device and a second delay device arranged in series. There are at least three electrical signals, and the third signal of the at least three electrical signals reaches the switching device through the second signal regulating device and the second delay device.

8. A laser radar signal receiving method, characterized in that: The laser radar signal receiving method comprises the following steps: A photoelectric conversion device is used to receive the laser pulse signal and convert it into at least two electrical signals, wherein the at least two electrical signals include a first signal and a second signal; Using a first signal conditioning device to perform gain or attenuation adjustment on the first signal or the second signal; controlling the first signal and the second signal to reach the switching device at different times; A signal amplifier is used to amplify the output signal of the switching device; Using an analog-to-digital converter to convert the electrical signals outputted at different times by the signal amplifier into digital signals at different times; If the digital signal at different moments is smaller than the reference non-saturation signal threshold, the digital signal at that moment is a valid feedback signal.

9. The laser radar signal receiving method according to claim 8, wherein: If the digital signals at different moments are all greater than or equal to the reference non-saturation signal threshold, the amplification factor of the signal amplifying device is adjusted until the digital signal at any moment is less than the reference non-saturation signal threshold.

10. The laser radar signal receiving method according to claim 8, wherein: If the digital signals at different times are all smaller than the reference non-saturation signal threshold, the digital signal corresponding to the electrical signal that has not been conditioned by the first signal conditioning device is selected as the effective feedback signal.

11. The laser radar signal receiving method according to any one of claims 8 to 10, characterized in that: The switch device is controlled to be in an enabled state or a disabled state at different moments, wherein the switch device outputs the electrical signal at the current moment without attenuation when the switch device is in the enabled state, and outputs the electrical signal at the current moment with attenuation when the switch device is in the disabled state.

12. A laser radar, characterized in that: The laser radar includes a laser radar transmitting system and a laser radar receiving system according to any one of claims 1 to 7, wherein the laser radar transmitting system is used to transmit a laser pulse signal to the detection object, and the photoelectric conversion device of the laser radar receiving system is used to receive the laser pulse signal reflected back by the detection object.

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