CN114428239A - Laser radar, method for acquiring flight time of laser radar, method for measuring distance of laser radar, and storage medium - Google Patents

Laser radar, method for acquiring flight time of laser radar, method for measuring distance of laser radar, and storage medium Download PDF

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Publication number
CN114428239A
CN114428239A CN202111674545.7A CN202111674545A CN114428239A CN 114428239 A CN114428239 A CN 114428239A CN 202111674545 A CN202111674545 A CN 202111674545A CN 114428239 A CN114428239 A CN 114428239A
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pulse signal
ranging
light pulse
time
signal
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Chinese (zh)
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任建峰
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O Net Technologies Shenzhen Group Co Ltd
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O Net Communications Shenzhen Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/487—Extracting wanted echo signals, e.g. pulse detection

Abstract

The invention discloses a laser radar, a flight time obtaining method, a distance measuring method and a storage medium thereof, wherein the laser radar comprises the following components: the control unit is used for generating an optical pulse trigger signal; the laser is connected with the control unit and is used for triggering by a light pulse trigger signal to emit a first ranging light pulse signal and a second ranging light pulse signal, wherein the second ranging light pulse signal is amplified in the laser through an amplifying light path and has internal delay; the photoelectric detector is connected with the control unit and used for receiving the first ranging light pulse signal and carrying out photoelectric conversion on the first ranging light pulse signal so that the control unit can obtain the transmitting moment of the first ranging light pulse signal; and the optical receiver is used for receiving an echo signal returned by the second ranging optical pulse signal irradiating the object to be measured and carrying out photoelectric conversion on the echo signal so as to enable the control unit to acquire the receiving moment of the echo signal. An additional photoelectric detection circuit is omitted, and the system cost is reduced.

Description

Laser radar, method for acquiring flight time of laser radar, method for measuring distance of laser radar, and storage medium
Technical Field
The invention relates to the technical field of laser measurement, in particular to a laser radar, a flight time obtaining method, a distance measuring method and a storage medium thereof.
Background
Along with the development of novel intelligent products such as mobile robot, laser ranging technique wide application is unmanned, and unmanned aerial vehicle keeps away the barrier planning automatically, and the while has proposed new requirement to laser ranging technique range finding performance, range finding precision, consumption, volume, stability, reliability. The pulse laser radar has the advantages of large measurement range, low requirement on light source coherence and the like, and is widely applied to the fields of military exploration, aerospace, robots and the like, so that the improvement of the pulse laser ranging precision is one of the future key development directions of the laser ranging technology.
The current common laser detection is a pulse direct detection mode. The system emits one or more laser pulse signals in the working process, when the emitted pulses irradiate a target object, a part of energy is correspondingly reflected and received by the detection system, and the detection system acquires the flight time of the laser pulses by measuring the time difference between the emitting time and the receiving time to measure the target distance D, Delta T, c/2 according to the speed of light in the air.
The method for calculating and acquiring the flight time of the received laser pulse is divided into two methods. One method is to use the laser emission time as the starting time, perform photoelectric conversion on the received laser pulse signal, obtain the time of laser pulse return by a comparator, and then obtain the laser pulse flight time delta T by a TDC (time-digital conversion) chip. The other method is that the laser emission time is used as the starting time, after the received laser pulse signal is subjected to photoelectric conversion, the waveform information of the echo signal is acquired by an ADC (analog-digital conversion) chip, and the time information returned by the laser pulse is obtained by a digital signal processing method, so that the laser pulse flight time delta T is obtained according to ADC sampling clock information. In the two methods, to accurately obtain the laser pulse flight time Δ T, the accurate laser pulse emitting time T0 and the target reflected laser pulse receiving time T1 need to be known. There are several ways in which the transmission time T0 can be obtained.
The first is to use the trigger pulse of the control circuit, and this scheme has the disadvantage that the time delay from the circuit trigger time to the laser emission time is introduced when calculating the laser pulse flight time, and this part of the time delay also has time delay jitter due to factors such as the drive circuit parameters and the laser response, thereby introducing extra errors in the flight time measurement.
The second method is to use the light emitting pulse of the laser and then obtain the real pulse of the laser emitting time through the photoelectric conversion circuit, thus eliminating the extra error in the former method. However, the method has the problems that the determined laser emission time information has high dependence on the laser pulse power, and when the laser radar needs to adjust the light emitting power to detect targets at different distances, the T0 time information introduced by different light emitting powers changes, so that the ranging precision of the system is influenced; the intensity tracking compensation will lead to a complex system. In practice, in order to measure a short-distance target, a separate photodetector is often needed to detect the light-emitting time T0, so that the light-emitting time T0 is separated from the detection circuit of the target echo signal time T1, and more photoelectric circuits are introduced.
Disclosure of Invention
The invention provides a laser radar, a flight time obtaining method, a distance measuring method and a storage medium thereof, and aims to solve the problem that in order to measure a short-distance target, a light-emitting time T0 is often required to be detected by a separate photoelectric detector so as to be separated from a detection circuit of a target echo signal time T1 and more photoelectric circuits are introduced.
In a first aspect, the present invention provides a lidar comprising: the control unit is used for generating an optical pulse trigger signal; the laser is connected with the control unit and is used for being triggered by the optical pulse trigger signal to emit a first ranging optical pulse signal and a second ranging optical pulse signal, wherein the second ranging optical pulse signal is amplified in the laser through an amplifying optical path and has internal delay; the photoelectric detector is connected with the control unit and used for receiving the first ranging light pulse signal and performing photoelectric conversion on the first ranging light pulse signal so that the control unit can acquire the transmitting time of the first ranging light pulse signal; and the receiving time is used for receiving the echo signal returned by the second ranging light pulse signal irradiating the object to be measured and carrying out photoelectric conversion on the echo signal so that the control unit can obtain the echo signal.
Further, the laser comprises a seed light source, a beam splitter and an amplifying optical path, wherein the seed light source is triggered by the optical pulse trigger signal to emit a seed optical pulse signal; the optical splitter is used for splitting the seed optical pulse signal to obtain a first ranging optical pulse signal and a second ranging optical pulse signal; the amplifying optical path is connected with the control unit, and the amplifying optical path is driven by the control unit to amplify the second ranging optical pulse signal.
Further, the amplifying optical path includes a pump driver, a pump, and an optical amplifier, the control unit, the pump driver, and the pump are sequentially connected, the control unit is configured to control the pump driver to drive the pump to provide pump light, and the optical amplifier is configured to receive the second ranging light pulse signal and amplify the second ranging light pulse signal by using the pump light.
Further, the optical amplifier is any one of an optical fiber amplifier, a raman optical amplifier, and a semiconductor optical amplifier.
Further, the laser radar further comprises a transceiver module and a scanning system, wherein the transceiver module is used for transmitting the second ranging optical pulse signal to the scanning system, and receiving an echo signal corresponding to the second ranging optical pulse signal and transmitting the echo signal to the photodetector; the scanning system is used for scanning an object to be detected by using the second ranging light pulse signal and receiving a returned echo signal to send the echo signal to the light receiving and sending module.
Furthermore, the laser radar further comprises a time acquisition unit, the time acquisition unit comprises a signal amplification circuit and a conversion chip, and the control unit, the conversion chip, the signal amplification circuit and the photoelectric detector are sequentially connected.
Further, the photodetector is a photodiode or an avalanche photodiode.
In a second aspect, the present invention further provides a method for acquiring a time of flight of a laser radar, which is applied to the laser radar according to the first aspect, and the method for acquiring a time of flight includes: transmitting a first ranging light pulse signal and a second ranging light pulse signal; acquiring the transmitting time of the first ranging light pulse signal; acquiring the receiving time of an echo signal corresponding to the second ranging optical pulse signal; and determining the flight time according to the transmitting time and the receiving time.
In a third aspect, the present invention further provides a ranging method for a laser radar, which is applied to the laser radar according to the first aspect, and the ranging method includes: transmitting a first ranging light pulse signal and a second ranging light pulse signal; acquiring the transmitting time of the first ranging light pulse signal; acquiring the receiving time of an echo signal corresponding to the second ranging optical pulse signal; determining flight time according to the transmitting time and the receiving time; and measuring the distance of the object to be measured according to the flight time and the internal delay.
In a fourth aspect, the present invention also provides a storage medium storing a computer program comprising program instructions which, when executed by a processor, implement the steps of the method according to the second aspect, or implement the steps of the method according to the third aspect.
Compared with the prior art, the invention has the beneficial effects that: triggering the laser to transmit a first ranging light pulse signal and a second ranging light pulse signal through the control unit, acquiring the transmitting time of the first ranging light pulse signal through the photoelectric detector by the control unit, and amplifying the second ranging light pulse signal through an amplifying light path in the laser to cause internal delay, so that the control unit can acquire the receiving time of an echo signal corresponding to the second ranging light pulse signal through the same photoelectric detector, and does not need to separately set the photoelectric detector to detect the transmitting time, thereby avoiding introducing more photoelectric light paths, simplifying the system structure, reducing the complexity of signal processing and simultaneously ensuring the measurement precision.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 shows a schematic diagram of a lidar in accordance with an embodiment of the invention;
FIG. 2 illustrates a waveform of an optical pulse of a lidar in accordance with an embodiment of the present invention;
FIG. 3 is a flowchart illustrating steps of a method for acquiring a time of flight of a lidar according to an embodiment of the invention;
FIG. 4 is a flow chart showing steps of a ranging method of a laser radar according to an embodiment of the present invention;
10. a control unit; 20. a laser; 21. a seed light source; 22. a light splitter; 23. amplifying the light path; 231. driving a pump; 232. pumping; 233. an optical amplifier; 30. a photodetector; 40. a transmitting and receiving optical module; 50. a scanning system; 60. a time acquisition unit; 61. a signal amplification circuit; 62. and converting the chip.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
Referring to fig. 1, an embodiment of the present invention provides a laser radar, including: a control unit 10, a laser 20 and a photodetector 30, the control unit 10 being adapted to generate a light pulse trigger signal; a laser 20 connected to the control unit 10, and configured to be triggered by the optical pulse trigger signal to emit a first ranging optical pulse signal and a second ranging optical pulse signal, where the second ranging optical pulse signal is amplified inside the laser 20 through an amplification optical path 23 and has an internal delay; a photodetector 30, configured to be connected to the control unit 10, and configured to receive the first ranging light pulse signal and perform photoelectric conversion on the first ranging light pulse signal, so that the control unit 10 obtains a transmission time of the first ranging light pulse signal; and a receiving moment for receiving the echo signal returned by the second ranging light pulse signal irradiating the object to be measured and performing photoelectric conversion on the echo signal so that the control unit 10 can acquire the echo signal.
The laser 20 is triggered to emit the first ranging light pulse signal and the second ranging light pulse signal through the control unit 10, the control unit 10 acquires the emission time of the first ranging light pulse signal through the photoelectric detector 30, and the second ranging light pulse signal is amplified in the laser 20 through the amplifying light path 23 and has internal delay, so that the control unit 10 can acquire the receiving time of the echo signal corresponding to the second ranging light pulse signal through the same photoelectric detector 30, the emission time does not need to be detected by additionally and independently setting the photoelectric detector 30, more photoelectric light paths are avoided being introduced, the system structure can be simplified, the signal processing complexity is reduced, and the measurement accuracy is ensured.
In an embodiment, the laser 20 includes a seed light source 21, a beam splitter 22 and an amplifying optical path 23, the seed light source 21 is configured to be triggered by the light pulse trigger signal to emit a seed light pulse signal; the optical splitter 22 is configured to split the seed optical pulse signal to obtain a first ranging optical pulse signal and a second ranging optical pulse signal; the amplifying optical path 23 is connected to the control unit 10, and the amplifying optical path 23 is driven by the control unit 10 to amplify the second ranging optical pulse signal. The seed light source 21 may be, for example, a seed laser diode, which may generate a pulse of light of a stable power. The light pulse trigger signal generated by the control unit 10 is used to trigger the seed light source 21. The seed light pulse signal emitted from the seed light source 21 is split by the beam splitter 22 to obtain a first ranging light pulse signal and a second ranging light pulse signal. The first ranging light pulse signal is not emitted outside the lidar, but is directly emitted to the photodetector 30 of the lidar, and is subjected to photoelectric conversion by the photodetector 30, so that the control unit 10 can acquire the emission time. The second ranging light pulse signal is emitted to the laser radar after passing through the amplifying light path 23 and irradiates on the object to be detected, the object to be detected reflects an echo signal and returns to the laser radar, the echo signal is received by the same photoelectric detector 30, and the control unit 10 acquires the receiving time after the photoelectric conversion is performed on the echo signal by the photoelectric detector. Since the second ranging light pulse signal is amplified by the amplification light path 23 of the laser 20 and is emitted from the laser 20 later than the first ranging light pulse signal, there is an internal delay in the second ranging light pulse signal. Therefore, when the laser radar measures a short-distance target, for example, a nearest distance target (0-distance target), the return receiving time of the echo signal is later than the reflection time of the first ranging light pulse signal, so that the same photodetector 30 can be used to detect the transmitting time and the receiving time, and the normal working effect cannot be influenced by the mutual interference caused by the small time difference between the two signals.
Specifically, the amplifying optical path 23 includes a pump driver 231, a pump 232, and an optical amplifier 233, the control unit 10, the pump driver 231, and the pump 232 are connected in sequence, the control unit 10 is configured to control the pump driver 231 to drive the pump 232 to provide pump light, and the optical amplifier 233 is configured to receive the second ranging light pulse signal and amplify the second ranging light pulse signal with the pump light. The optical amplifier 233 is any one of an optical fiber amplifier, a raman optical amplifier 233, and a semiconductor optical amplifier 233. The photodetector 30 is a photodiode or an avalanche photodiode. The control unit 10 sends a control signal to control the pump driver 231 to operate, and the pump driver 231 may be a driving circuit or a driving chip, which drives the pump to emit pump light into the optical amplifier 233. The second ranging optical pulse signal emitted after being split by the optical splitter 22 enters the optical amplifier 233, and the optical amplifier 233 performs gain amplification on the second ranging optical pulse signal by using the pump light, so that the seed optical pulse signal with lower power can be amplified to a certain extent for detecting the object distance. Wherein, because laser instrument 20 is in the course of the work, seed light source 21 luminous power is stable for when surveying different distance targets, laser instrument 20 adjusts detection laser power through adjusting pumping power and also can not have amplitude variation, measurement emission moment that can be more accurate.
In an embodiment, the lidar further includes a transceiver module 40 and a scanning system 50, where the transceiver module 40 is configured to transmit the second ranging light pulse signal to the scanning system 50, and is configured to receive an echo signal corresponding to the second ranging light pulse signal and transmit the echo signal to the photodetector 30; the scanning system 50 is configured to scan the object to be measured with the second ranging light pulse signal and receive a return echo signal to send to the transceiver module 40. The laser radar further comprises a time acquisition unit 60, the time acquisition unit 60 comprises a signal amplification circuit 61 and a conversion chip 62, and the control unit 10, the conversion chip 62, the signal amplification circuit 61 and the photoelectric detector 30 are sequentially connected. Wherein the scanning system 50 can be rotated to adjust the angle of the detected object to improve the measurement range. The transmission/reception optical module 40 in this embodiment is an optical module integrating a transmission function and a reception function, and may be used for transmitting an optical pulse signal or receiving an optical pulse signal. The signal amplifying circuit 61 may be a trans-impedance amplifier (TIA). The conversion chip 62 may be an ADC (Analog to Digital Converter) for converting the electrical signal into a Digital signal. The conversion chip 62 may also be a TDC (Time to Digital converter).
The operation of the laser radar of the present embodiment is described below in conjunction with the waveform diagram of the light pulse.
First, the control unit 10 generates a light pulse trigger signal to the seed light source 21 of the laser 20, and the seed light source 21 is triggered by the trigger signal to emit a seed light pulse signal. Wherein there is a driving delay in the generation of the light pulse trigger signal by the control unit 10 until the seed light source 21 emits the seed light pulse signal. As shown in fig. 1, the first waveform is a waveform in which the control unit 10 generates the light pulse trigger signal, and the second waveform is a waveform in which the seed light source 21 generates the seed light pulse signal. In the first waveform, when the trigger signal is generated, in the second waveform, the seed light pulse signal is not generated yet, but is generated after delaying for a period of time. The time difference between the two waveforms is the drive delay.
The seed optical pulse signal is split by the splitter 22 to obtain a first ranging optical pulse signal and a second ranging optical pulse signal. The first ranging laser directly exits to the photoelectric energy detector, and the control unit 10 acquires the pulse waveform thereof. The second ranging light pulse signal is amplified by the amplification light path 23 and then emitted from the laser 20. As in fig. 1, the seed light pulse signal of the second waveform represents the first ranging light pulse signal; the third waveform of the laser 20 light pulse signal represents the second ranging light pulse signal. The first ranging light pulse signal and the second ranging light pulse signal are both obtained by splitting light from the seed light pulse signal, and the first ranging light pulse signal and the second ranging light pulse signal are generated simultaneously. Comparing the third waveform with a second waveform in which the first ranging light pulse signal is directly emitted from the laser 20 and can be used for indicating the emission time T0 of the laser; in the third waveform, the second ranging light pulse signal is amplified by the amplification optical path 23 inside the laser 20 and then emitted from the laser 20, and therefore, the second ranging light pulse signal has an internal delay. The difference between the two waveforms is the internal delay. It should be noted that the internal delay is a fixed value, and can be obtained through measurement.
The second ranging optical pulse signal returns an echo signal after passing through the transceiver module 40, the scanning system 50 and the object to be measured in sequence. As in fig. 1, the probe laser echo pulse of the fourth waveform represents the echo signal. And comparing the fourth waveform with the third waveform, wherein in the fourth waveform, the moment of capturing the echo pulse is the moment T1 of receiving the laser, and the difference value between the two waveforms is the flight time of the actual detection laser.
As shown in fig. 1, the fifth waveform is a waveform in which the photodetector 30 photoelectrically converts the first ranging light pulse signal and the echo signal. Comparing the fifth waveform with the second waveform, the photodetector 30 simultaneously generates corresponding electrical signals while the first ranging optical pulse signal is generated, and the emission time T0 of the first ranging optical pulse signal is obtained. Comparing the fifth waveform with the fourth waveform, the photodetector 30 simultaneously generates corresponding electrical signals when receiving the echo pulse, and then obtains the receiving time T1 of the echo signal. Then the time difference Δ T between T1 and T0 is the time of flight of the laser. Therefore, the flight time of the actual detection laser can be obtained by subtracting the internal delay from the flight time of the laser.
Compared with the existing scheme, the laser radar of the embodiment has the advantages that the method that seed light is led out to directly reach the main photoelectric detector 30 of the laser radar is adopted, the measurement precision of system time is guaranteed, meanwhile, an extra photoelectric detection circuit is omitted, and the system cost is reduced. The method can be mainly applied to the fields of unmanned driving sensing, 3-D mapping, AGV navigation and the like.
The embodiment of the invention also provides a method for acquiring the flight time of the laser radar, which comprises the following steps:
and S101, emitting a first ranging light pulse signal and a second ranging light pulse signal.
And S102, acquiring the transmitting time of the first ranging light pulse signal.
And S103, acquiring the receiving time of the echo signal corresponding to the second ranging light pulse signal.
And S104, determining the flight time according to the transmitting time and the receiving time.
The emitting time of the first ranging light pulse signal is T0, and the receiving time of the echo signal corresponding to the second ranging light pulse signal is T1. The time of flight is Δ T. T1-T0.
Specifically, in the laser, a part of energy is directly led out from the SEED optical power through the light splitting device and sent to the main receiving photoelectric detector (usually APD, PD, etc.) of the laser radar, and because the laser is in the working process, the SEED optical power is stable, and the laser does not have amplitude variation when adjusting the detection laser power (for detecting different distance targets) by adjusting the PUMP power, so that the laser emission time T0 can be measured more accurately. Meanwhile, due to the fact that the time delay from the SEED light emitting time to the laser light emitting time exists in the laser, namely in the working process of the laser radar, the laser echo of the nearest distance (0 distance target) is later than the SEED light emitting time, the same photoelectric detector can be used for detecting T0 and T1, and the normal working effect cannot be influenced due to mutual interference caused by too small time difference of two signals.
The embodiment of the invention also provides a ranging method of the laser radar, which comprises the following steps:
and S201, emitting a first ranging light pulse signal and a second ranging light pulse signal.
S202, acquiring the transmitting time of the first ranging light pulse signal.
And S203, acquiring the receiving time of the echo signal corresponding to the second ranging light pulse signal.
And S204, determining the flight time according to the transmitting time and the receiving time.
And S205, measuring the distance of the object to be measured according to the flight time and the internal delay.
Specifically, the lidar ranging value D ═ Δ T × c/2, and Δ T measured in this embodiment is between the first ranging light pulse emission time T0 and the laser echo signal time T1The time difference is larger than the actual flight time, and because the delay time of the internal optical path of the laser is fixed, a fixed value is subtracted when the distance is calculated. Wherein the delay fixed time is TDelay timeThen D ═ Δ T-TDelay time) C/2. Compared with the existing scheme, the method can simplify the system structure, reduce the complexity of signal processing and simultaneously ensure the measurement precision.
It will be understood by those skilled in the art that all or part of the flow of the method implementing the above embodiments may be implemented by a computer program instructing associated hardware. The computer program includes program instructions, and the computer program may be stored in a storage medium, which is a computer-readable storage medium. The program instructions are executed by at least one processor in the computer system to implement the flow steps of the embodiments of the method described above.
Accordingly, the present invention also provides a storage medium. The storage medium may be a computer-readable storage medium. The storage medium stores a computer program, wherein the computer program comprises program instructions.
The program instructions, when executed by the processor, cause the processor to perform the steps of: a first ranging light pulse signal and a second ranging light pulse signal are transmitted. And acquiring the transmitting moment of the first ranging light pulse signal. And acquiring the receiving time of the echo signal corresponding to the second ranging light pulse signal. And determining the flight time according to the transmitting time and the receiving time.
The program instructions, when executed by the processor, cause the processor to perform the steps of: a first ranging light pulse signal and a second ranging light pulse signal are transmitted. And acquiring the transmitting moment of the first ranging light pulse signal. And acquiring the receiving time of the echo signal corresponding to the second ranging light pulse signal. And determining the flight time according to the transmitting time and the receiving time. And measuring the distance of the object to be measured according to the flight time and the internal delay.
The storage medium may be a usb disk, a removable hard disk, a Read-Only Memory (ROM), a magnetic disk, or an optical disk, which can store various computer readable storage media.
Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein may be embodied in electronic hardware, computer software, or combinations of both, and that the components and steps of the examples have been described in a functional general in the foregoing description for the purpose of illustrating clearly the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative. For example, the division of each unit is only one logic function division, and there may be another division manner in actual implementation. For example, various elements or components may be combined or may be integrated into another system, or some features may be omitted, or not implemented.
The steps in the method of the embodiment of the invention can be sequentially adjusted, combined and deleted according to actual needs. The units in the device of the embodiment of the invention can be merged, divided and deleted according to actual needs. In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a storage medium. Based on such understanding, the technical solution of the present invention essentially or partially contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a terminal, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A lidar, comprising:
a control unit for generating a light pulse trigger signal;
the laser is connected with the control unit and is used for being triggered by the optical pulse trigger signal to emit a first ranging optical pulse signal and a second ranging optical pulse signal, wherein the second ranging optical pulse signal is amplified in the laser through an amplifying optical path to have internal time delay;
the photoelectric detector is connected with the control unit and used for receiving the first ranging light pulse signal and performing photoelectric conversion on the first ranging light pulse signal so that the control unit can acquire the transmitting time of the first ranging light pulse signal; and the receiving time is used for receiving the echo signal returned by the second ranging light pulse signal irradiating the object to be measured and carrying out photoelectric conversion on the echo signal so that the control unit can obtain the echo signal.
2. The lidar of claim 1, wherein the laser comprises a seed light source, a beam splitter, and an amplification optical path, the seed light source being configured to be triggered by the optical pulse trigger signal to emit a seed optical pulse signal; the optical splitter is used for splitting the seed optical pulse signal to obtain a first ranging optical pulse signal and a second ranging optical pulse signal; the amplifying optical path is connected with the control unit, and the amplifying optical path is driven by the control unit to amplify the second ranging optical pulse signal.
3. The lidar of claim 2, wherein the amplification optical path comprises a pump driver, a pump, and an optical amplifier, the control unit, the pump driver, and the pump being connected in sequence, the control unit being configured to control the pump driver to drive the pump to provide pump light, and the optical amplifier being configured to receive the second ranging light pulse signal and amplify the second ranging light pulse signal with the pump light.
4. The lidar of claim 3, wherein the optical amplifier is any one of a fiber amplifier, a Raman optical amplifier, and a semiconductor optical amplifier.
5. The lidar of claim 3, further comprising a transceiver module and a scanning system, wherein the transceiver module is configured to transmit the second ranging light pulse signal to the scanning system, and to receive an echo signal corresponding to the second ranging light pulse signal and transmit the echo signal to the photodetector; the scanning system is used for scanning an object to be detected by using the second ranging light pulse signal and receiving a returned echo signal to send the echo signal to the transceiver module.
6. The lidar of claim 5, further comprising a time acquisition unit, wherein the time acquisition unit comprises a signal amplification circuit and a conversion chip, and the control unit, the conversion chip, the signal amplification circuit and the photodetector are connected in sequence.
7. Lidar according to any of claims 1 to 6, wherein said photodetector is a photodiode or an avalanche photodiode.
8. A time-of-flight acquisition method of a lidar for use in the lidar of any of claims 1-7, the time-of-flight acquisition method comprising:
transmitting a first ranging light pulse signal and a second ranging light pulse signal;
acquiring the transmitting time of the first ranging light pulse signal;
acquiring the receiving time of an echo signal corresponding to the second ranging optical pulse signal;
and determining the flight time according to the transmitting time and the receiving time.
9. A ranging method of a laser radar applied to the laser radar according to any one of claims 1 to 7, the ranging method comprising:
transmitting a first ranging light pulse signal and a second ranging light pulse signal;
acquiring the transmitting time of the first ranging light pulse signal;
acquiring the receiving time of an echo signal corresponding to the second ranging optical pulse signal;
determining flight time according to the transmitting time and the receiving time;
and measuring the distance of the object to be measured according to the flight time and the internal delay.
10. A storage medium, characterized in that the storage medium stores a computer program comprising program instructions which, when executed by a processor, implement the steps of the method as claimed in claim 8 or the steps of the method as claimed in claim 9.
CN202111674545.7A 2021-12-31 2021-12-31 Laser radar, method for acquiring flight time of laser radar, method for measuring distance of laser radar, and storage medium Pending CN114428239A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114637021A (en) * 2022-05-18 2022-06-17 四川吉埃智能科技有限公司 Sub-centimeter-level full-waveform laser radar ranging method and device
CN114994639A (en) * 2022-08-08 2022-09-02 四川吉埃智能科技有限公司 Method for realizing sub-centimeter-level measurement precision by laser scanning radar
CN115184907A (en) * 2022-09-08 2022-10-14 北醒（北京）光子科技有限公司 Balance detection circuit and laser ranging system
CN115877395A (en) * 2023-02-01 2023-03-31 深圳煜炜光学科技有限公司 Laser radar and ranging method thereof

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114637021A (en) * 2022-05-18 2022-06-17 四川吉埃智能科技有限公司 Sub-centimeter-level full-waveform laser radar ranging method and device
CN114994639A (en) * 2022-08-08 2022-09-02 四川吉埃智能科技有限公司 Method for realizing sub-centimeter-level measurement precision by laser scanning radar
CN114994639B (en) * 2022-08-08 2022-11-15 四川吉埃智能科技有限公司 Method for realizing sub-centimeter-level measurement precision by laser scanning radar
CN115184907A (en) * 2022-09-08 2022-10-14 北醒（北京）光子科技有限公司 Balance detection circuit and laser ranging system
CN115877395A (en) * 2023-02-01 2023-03-31 深圳煜炜光学科技有限公司 Laser radar and ranging method thereof

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