Laser radar structure capable of improving penetration performance

Abstract

The utility model belongs to the technical field of laser radar structures, and particularly relates to a laser radar structure capable of improving penetration performance, which is characterized in that an echo receiving module is provided with a photoelectric receiving unit, a gain control unit, a distance gain generation unit and a matched filtering unit, and a distance gain generation power supply controls the gain of the gain control unit to increase along with time; therefore, the amplification of the laser echo signal changes along with the detection distance, the gain of the short-distance echo signal is low, the gain of the long-distance echo signal is high, the excessive gain of the short-distance signal in a severe air environment is avoided, the ability of the laser radar to penetrate through haze, rain, snow or dust is improved, and the detection accuracy is improved. And popularization and application of the laser radar in an outdoor environment are facilitated.

Description

Technical Field

[0001] The utility model belongs to the technical field of laser radar structures, and in particular relates to a laser radar structure with improved penetration performance. Background Art

[0002] LiDAR is widely used outdoors, including real-time detection of the surrounding environment in autonomous driving, helping cars to locate, avoid obstacles and navigate, measuring surface elevation and building height in terrain mapping, measuring building dimensions and monitoring building structures in construction, which can effectively improve work efficiency, reduce manpower and material costs, and achieve high-precision measurement and monitoring. However, when used outdoors, LiDAR often encounters harsh working conditions, such as haze, rain, snow, and dust. When the laser emitted by LiDAR passes through haze, rain, snow or dust, it undergoes multiple refractions and reflections. In the absence of physical obstacles, it will also return a strong laser echo signal at a close distance, so that the echo receiving module detects the laser echo, forming noise or even erroneous ranging signals, which limits the promotion and application of LiDAR under harsh working conditions. Utility Model Content

[0003] The technical problem to be solved by the utility model is to overcome the defect in the prior art that the ranging result of the laser radar in the harsh air environment is easily disturbed, thereby providing a laser radar structure with improved penetration performance.

[0004] A laser radar structure with improved penetration performance, comprising a laser emission module, an echo receiving module and a time counting module;

[0005] The echo receiving module includes a photoelectric receiving unit, a gain control unit, a distance gain generating unit and a matched filtering unit; the photoelectric receiving unit receives the laser echo and converts the laser echo into a voltage signal; the gain control unit is connected to the photoelectric receiving unit and amplifies the voltage signal to form an amplified signal; the distance gain generating unit is connected to the gain control unit and controls the gain of the gain control unit to increase over time; the matched filtering unit is connected to the gain control unit and filters the amplified signal to form a filtered signal;

[0006] The laser emission module is used to emit an outgoing laser; the distance gain generating unit is connected to the laser emission module, and starts to adjust the gain of the gain control unit when the laser emission module emits an outgoing laser; the time counting module is connected to the laser emission module and the echo receiving module, and is used to realize the timing from emitting the outgoing laser to receiving the laser echo.

[0007] Furthermore, the laser emission module includes a laser driving unit and a laser emission unit, the laser driving unit generates a trigger signal, and the laser emission unit emits an outgoing laser according to the trigger signal.

[0008] Furthermore, the time counting module includes a time counting unit, a first analog-to-digital conversion unit and a second analog-to-digital conversion unit; the first analog-to-digital conversion unit is connected to the output end of the laser emitting unit, and the second analog-to-digital conversion unit is connected to the output end of the matched filtering unit; the time technology unit is respectively connected to the first analog-to-digital conversion unit and the second analog-to-digital conversion unit.

[0009] Furthermore, it also includes a laser power configuration unit, which is connected to the laser driving unit and is used to control the output laser power emitted by the laser emitting module.

[0010] Furthermore, it also includes a processor unit; the processor unit is connected to the laser power configuration unit and is used to control the output of the laser power configuration unit; the processor unit is connected to the time counting unit and is used to obtain the echo time and calculate the ranging result.

[0011] Furthermore, the photoelectric receiving unit includes a photodiode, a second triode, a third triode, a fifth resistor and a sixth resistor; the cathode of the photodiode is connected to a constant current high-voltage DC power supply, and the positive electrode is connected to the base of the second triode; the collector of the second triode is connected to the constant current high-voltage DC power supply, and the emitter is connected to the first end of the sixth resistor; the second end of the sixth resistor is grounded; the first end of the fifth resistor is connected to the constant current high-voltage DC power supply, and the second end is connected to the collector of the third triode; the base of the third triode is connected to the emitter of the second triode, and the emitter of the third triode is grounded; the collector of the third triode outputs a voltage signal.

[0012] Furthermore, the gain control unit is an adjustable gain operational amplifier of model AD8337.

[0013] Furthermore, the distance gain generating unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a third capacitor and a first transistor; the first end of the fourth resistor is connected to a DC power supply, and the second end is connected to the first end of the third resistor; the second end of the third resistor is connected to the collector of the first transistor; the first end of the third capacitor is connected to the second end of the fourth resistor, and the second end is grounded; the first end of the second capacitor is connected to the second end of the third resistor, and the second end is grounded; the first end of the first resistor is connected to the second end of the third resistor, and the second end is connected to the first end of the first capacitor; the second end of the first capacitor is grounded; the base of the first transistor is connected to the second end of the second resistor, and the emitter is grounded; the first end of the second resistor is connected to the laser emission module; the collector of the first transistor is connected to the gain control unit.

[0014] Further, the matching filter module includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a fourth capacitor, a fifth capacitor and an inductor; the second end of the inductor is connected to the first end of the fourth capacitor; the first end of the seventh resistor is connected to the first end of the inductor, and the second end is connected to the second end of the fourth capacitor; the first end of the eighth resistor is connected to the first end of the inductor, and the second end is connected to the first end of the ninth resistor; the first end of the tenth resistor is connected to the second end of the eighth resistor, and the second end is connected to the first end of the fifth capacitor; the second end of the fifth capacitor is grounded; the first end of the inductor inputs the amplified signal, and the second end of the fourth capacitor outputs the filtered signal.

[0015] Beneficial effect: The utility model provides a laser radar structure with improved penetration performance. By arranging a photoelectric receiving unit, a gain control unit, a distance gain generating unit and a matching filter unit in the echo receiving module, the distance gain generating power supply controls the gain of the gain control unit to increase over time, thereby realizing that the amplification of the laser echo signal changes with the detection distance, the gain of the short-range echo signal is low, and the gain of the long-range echo signal is high, thereby avoiding excessive gain of the short-range signal in a harsh air environment, so that the laser radar improves the ability to penetrate haze, rain, snow or dust, which is conducive to the promotion and application of laser radar in outdoor environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1It is a schematic block diagram of the overall structure of the utility model;

[0018] Figure 2 This is a partial circuit structure schematic diagram of the utility model.

[0019] Explanation of the accompanying symbols: R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; R10, tenth resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, third capacitor; C5, fifth capacitor; Q1, first transistor; Q2, second transistor; Q3, third transistor; VCC, DC power supply; HVCC, constant current high voltage DC power supply; D1, photodiode; U1, adjustable gain operational amplifier; L1, inductor. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0021] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0022] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] Reference Figure 1 As shown, this embodiment provides a laser radar structure with improved penetration performance, including a laser transmitting module, an echo receiving module and a time counting module;

[0024] The echo receiving module includes a photoelectric receiving unit, a gain control unit, a distance gain generating unit and a matched filtering unit; the photoelectric receiving unit receives the laser echo and converts the laser echo into a voltage signal; the gain control unit is connected to the photoelectric receiving unit and amplifies the voltage signal to form an amplified signal; the distance gain generating unit is connected to the gain control unit and sends a gain control signal to control the gain of the gain control unit to increase over time; the matched filtering unit is connected to the gain control unit and filters the amplified signal to form a filtered signal;

[0025] The laser emission module is used to emit an outgoing laser; the distance gain generating unit is connected to the laser emission module, and starts to adjust the gain of the gain control unit when the laser emission module emits an outgoing laser; the time counting module is connected to the laser emission module and the echo receiving module, and is used to realize the timing from emitting the outgoing laser to receiving the laser echo.

[0026] The present embodiment provides a laser radar structure with improved penetration performance. By arranging a photoelectric receiving unit, a gain control unit, a distance gain generating unit and a matched filtering unit in the echo receiving module, the distance gain generating power supply controls the gain of the gain control unit to increase over time, thereby realizing that the amplification of the laser echo signal changes with the detection distance, the gain of the short-range echo signal is low, and the gain of the long-range echo signal is high, thereby avoiding excessive gain of the short-range signal in a harsh air environment, so that the laser radar improves the ability to penetrate haze, rain, snow or dust, which is conducive to the promotion and application of laser radar in outdoor environments.

[0027] Specifically, the laser emitting module includes a laser driving unit and a laser emitting unit. The laser driving unit generates a trigger signal, and the laser emitting unit emits an outgoing laser according to the trigger signal.

[0028] The time counting module includes a time counting unit, a first analog-to-digital conversion unit and a second analog-to-digital conversion unit; the first analog-to-digital conversion unit is connected to the output end of the laser emitting unit, and the second analog-to-digital conversion unit is connected to the output end of the matched filter unit; the time technology unit is connected to the first analog-to-digital conversion unit and the second analog-to-digital conversion unit respectively. The first analog-to-digital conversion signal collects the analog pulse signal of the voltage change at both ends of the laser emitting unit when the laser emitting unit emits light, converts it into a digital pulse signal, and becomes the Start signal of the timing starting point and sends it to the time counting unit; the second analog-to-digital conversion unit converts the echo laser pulse signal separated by the matched filter unit into a digital pulse signal, and becomes the Stop signal of the stop time counting and sends it to the time counting unit; the time counting unit starts timing from the Start signal, and stops timing when the Stop signal is used as the ranging time.

[0029] It also includes a laser power configuration unit, which is connected to the laser driving unit and is used to control the output laser power emitted by the laser emitting module.

[0030] The system further comprises a processor unit; the processor unit is connected to the laser power configuration unit and is used to control the output of the laser power configuration unit; the processor unit is connected to the time counting unit and is used to obtain the echo time and calculate the ranging result. In this embodiment, the processor unit can preset different laser function configurations under different visibility conditions according to the visibility of the air, so as to achieve the best penetration detection effect.

[0031] Reference Figure 2 As shown, specifically, the photoelectric receiving unit includes a photodiode D1, a second transistor Q2, a third transistor Q3, a fifth resistor R5 and a sixth resistor R6; the cathode of the photodiode D1 is connected to a constant current high-voltage DC power supply HVCC, and the anode is connected to the base of the second transistor Q2; the collector of the second transistor Q2 is connected to the constant current high-voltage DC power supply HVCC, and the emitter is connected to the first end of the sixth resistor R6; the second end of the sixth resistor R6 is grounded; the first end of the fifth resistor R5 is connected to the constant current high-voltage DC power supply HVCC, and the second end is connected to the collector of the third transistor Q3; the base of the third transistor Q3 is connected to the emitter of the second transistor Q2, and the emitter of the third transistor Q3 is grounded; the collector of the third transistor Q3 outputs a voltage signal.

[0032] The gain control unit is an adjustable gain operational amplifier U1 of model AD8337.

[0033] The distance gain generating unit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a first transistor Q1; the first end of the fourth resistor R4 is connected to a DC power supply VCC, and the second end is connected to the first end of the third resistor R3; the second end of the third resistor R3 is connected to the collector of the first transistor Q1; the first end of the third capacitor C3 is connected to the second end of the fourth resistor R4, and the second end is grounded; the first end of the second capacitor C2 is connected to the second end of the third resistor R3, and the second end is grounded; the first end of the first resistor R1 is connected to the second end of the third resistor R3, and the second end is connected to the first end of the first capacitor C1; the second end of the first capacitor C1 is grounded; the base of the first transistor Q1 is connected to the second end of the second resistor R2, and the emitter is grounded; the first end of the second resistor R2 is connected to the laser emitting module; the collector of the first transistor Q1 is connected to the gain control unit.

[0034] The matching filter module includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a fourth capacitor C4, a fifth capacitor C5 and an inductor L1; the second end of the inductor L1 is connected to the first end of the fourth capacitor C4; the first end of the seventh resistor R7 is connected to the first end of the inductor L1, and the second end is connected to the second end of the fourth capacitor C4; the first end of the eighth resistor R8 is connected to the first end of the inductor L1, and the second end is connected to the first end of the ninth resistor R9; the first end of the tenth resistor R10 is connected to the second end of the eighth resistor R8, and the second end is connected to the first end of the fifth capacitor C5; the second end of the fifth capacitor C5 is grounded; the first end of the inductor L1 inputs the amplified signal, and the second end of the fourth capacitor C4 outputs the filtered signal.

[0035] In this embodiment, the pulse voltage signal of the laser echo is amplified by the variable gain of the gain generating unit, and the amplified echo pulse voltage signal and the gain control signal (DGC signal) are both variable AC signals, and the two AC signals are aliased in the amplifier. The echo pulse voltage signal is a high-frequency signal with a narrow pulse, and the bandwidth of the gain control signal is lower than the bandwidth of the echo pulse voltage signal. The matched filter unit separates the echo laser pulse signal from the overlapped signal according to the frequency characteristics of the echo laser pulse signal.

[0036] Workflow: First, the processor unit controls the laser power configuration unit to drive and adjust the driving power of the laser driving unit, generates a pulsed laser signal to drive the laser emitting unit to emit the outgoing laser; at the same time, the distance gain generation module starts to generate a changing gain control signal (DGC) according to the pulsed laser signal; at the same time, the first analog-to-digital conversion unit outputs a Start signal to the time counting power supply to start timing; the gain control unit continuously increases the amplifier gain multiple according to the gain control signal; the photoelectric receiving unit receives the laser echo and converts it into a voltage signal, enters the gain control unit to amplify it into an amplified signal, and then enters the matched filter unit to perform frequency selective filtering to separate the filtered signal; the second analog-to-digital conversion unit receives the filtered signal and outputs a Stop signal to the time counting unit, and the timing ends; the timing is the laser flight time, and the ranging distance is calculated.

[0037] Working principle:

[0038] Under the same atmospheric transmission conditions, the proportional relationship between different distances D and received energy T is:

[0039]

[0040] Where D a , D b Indicates different distances, T a is the energy value received at point a, T bThe amount of energy received at point b.

[0041] Therefore, in order to ensure that the energy values ​​received at different distances are consistent, different gains are set for different distances:

[0042]

[0043] Among them, D a , D b For different distances, G a , G b is the gain at different distances.

[0044] In this embodiment, laser echo signals at different distances enter the gain control unit at different times, so that the received energy values ​​at different distances can be made consistent by randomly controlling the gain of the gain control unit.

[0045] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A laser radar structure with improved penetration performance, characterized in that: It includes a laser emission module, an echo receiving module and a time counting module; The echo receiving module includes a photoelectric receiving unit, a gain control unit, a distance gain generating unit and a matched filtering unit; the photoelectric receiving unit receives the laser echo and converts the laser echo into a voltage signal; the gain control unit is connected to the photoelectric receiving unit and amplifies the voltage signal to form an amplified signal; the distance gain generating unit is connected to the gain control unit and controls the gain of the gain control unit to increase over time; the matched filtering unit is connected to the gain control unit and filters the amplified signal to form a filtered signal; The laser emission module is used to emit an outgoing laser; the distance gain generating unit is connected to the laser emission module, and starts to adjust the gain of the gain control unit when the laser emission module emits an outgoing laser; the time counting module is connected to the laser emission module and the echo receiving module, and is used to realize the timing from emitting the outgoing laser to receiving the laser echo.

2. A laser radar structure for improving penetration performance according to claim 1, characterized in that: The laser emitting module comprises a laser driving unit and a laser emitting unit. The laser driving unit generates a trigger signal, and the laser emitting unit emits an outgoing laser according to the trigger signal.

3. A laser radar structure for improving penetration performance according to claim 2, characterized in that: The time counting module includes a time counting unit, a first analog-to-digital conversion unit and a second analog-to-digital conversion unit; the first analog-to-digital conversion unit is connected to the output end of the laser emitting unit, and the second analog-to-digital conversion unit is connected to the output end of the matched filtering unit; the time technology unit is respectively connected to the first analog-to-digital conversion unit and the second analog-to-digital conversion unit.

4. A laser radar structure for improving penetration performance according to claim 3, characterized in that: It also includes a laser power configuration unit, which is connected to the laser driving unit and is used to control the output laser power emitted by the laser emitting module.

5. The laser radar structure for improving penetration performance according to claim 4, characterized in that: It also includes a processor unit; the processor unit is connected to the laser power configuration unit and is used to control the output of the laser power configuration unit; the processor unit is connected to the time counting unit and is used to obtain the echo time and calculate the ranging result.

6. The laser radar structure for improving penetration performance according to claim 1, characterized in that: The photoelectric receiving unit includes a photodiode, a second triode, a third triode, a fifth resistor and a sixth resistor; the cathode of the photodiode is connected to a constant current high-voltage DC power supply, and the anode is connected to the base of the second triode; the collector of the second triode is connected to the constant current high-voltage DC power supply, and the emitter is connected to the first end of the sixth resistor; the second end of the sixth resistor is grounded; the first end of the fifth resistor is connected to the constant current high-voltage DC power supply, and the second end is connected to the collector of the third triode; the base of the third triode is connected to the emitter of the second triode, and the emitter of the third triode is grounded; the collector of the third triode outputs a voltage signal.

7. The laser radar structure for improving penetration performance according to claim 1, characterized in that: The gain control unit is an adjustable gain operational amplifier of model AD8337.

8. The laser radar structure for improving penetration performance according to claim 1, characterized in that: The distance gain generating unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a third capacitor and a first transistor; the first end of the fourth resistor is connected to a DC power supply, and the second end is connected to the first end of the third resistor; the second end of the third resistor is connected to the collector of the first transistor; the first end of the third capacitor is connected to the second end of the fourth resistor, and the second end is grounded; the first end of the second capacitor is connected to the second end of the third resistor, and the second end is grounded; the first end of the first resistor is connected to the second end of the third resistor, and the second end is connected to the first end of the first capacitor; the second end of the first capacitor is grounded; the base of the first transistor is connected to the second end of the second resistor, and the emitter is grounded; the first end of the second resistor is connected to the laser emitting module; the collector of the first transistor is connected to the gain control unit.

9. The laser radar structure for improving penetration performance according to claim 1, characterized in that: The matching filter unit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a fourth capacitor, a fifth capacitor and an inductor; the second end of the inductor is connected to the first end of the fourth capacitor; the first end of the seventh resistor is connected to the first end of the inductor, and the second end is connected to the second end of the fourth capacitor; the first end of the eighth resistor is connected to the first end of the inductor, and the second end is connected to the first end of the ninth resistor; the first end of the tenth resistor is connected to the second end of the eighth resistor, and the second end is connected to the first end of the fifth capacitor; the second end of the fifth capacitor is grounded; the first end of the inductor inputs the amplified signal, and the second end of the fourth capacitor outputs the filtered signal.

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