A dual-field-of-view obstacle avoidance laser radar transmission system

Abstract

The present invention belongs to the field of laser detection technology, and specifically discloses a dual-field-of-view obstacle avoidance laser radar transmitting system, comprising: a laser transmitting system, a laser deflection system, a laser receiving system and a signal processing system; the laser transmitting system is used to transmit a laser beam; the laser deflection system is used to scan the laser beam so that the transmitted laser beam carries azimuth and pitch information; the laser receiving system is used to process the echo signals of scanning beams with different fields of view reflected by a target object; the signal processing system is used to record the emitted laser beam and the echo signal of the emitted laser beam reflected by the target object, and calculate the distance of the target object through the initial time and the end time recorded by a timer, and the signal processing system is connected to the laser receiving system; the present invention adopts a MEMS micro-scanning mirror to realize fast scanning of the light beam, and the reliability is improved, and adopts large and small dual fields of view to detect both a large field of view and a fine target.

Description

Technical Field

[0001] The invention belongs to the technical field of laser detection, and in particular relates to a dual-field-of-view obstacle avoidance laser radar transmitting system. Background Art

[0002] A helicopter is a convenient and efficient aircraft with advantages such as excellent low-altitude flight characteristics and easy take-off and landing. It has been widely used in military and civilian fields such as reconnaissance and mapping, material transportation, and disaster relief. Due to the structural characteristics of the helicopter itself and the complex terrain environment at low altitude, the survivability of the helicopter platform is poor. An important factor threatening the safety of the helicopter itself is that in complex terrain conditions such as mountains, plateaus, deserts, and forests, or in low visibility conditions caused by rain, snow, dust, and fog, the environment for helicopter take-off, flight, landing, and landing is full of uncertainty. The pilot's visual ability is severely limited, and he cannot quickly and effectively understand the external environment of the fuselage, and cannot effectively avoid dangerous targets and obstacles such as trees, wires, and towers on the track, which leads to accidents. In order to ensure the flight safety of helicopters and deal with the threats of power cables, antennas, and harsh conditions such as night, extreme weather, and dust, research on helicopter obstacle avoidance systems has been conducted at home and abroad;

[0003] Currently, most helicopter obstacle avoidance radars use mechanical rotating laser radars. The problems are that reliability is difficult to guarantee and the equipment is bulky. Summary of the invention

[0004] In order to solve the problems faced by the existing helicopter obstacle avoidance radar, the present invention proposes a dual-field-of-view obstacle avoidance laser radar transmitting system.

[0005] The present invention provides a dual-field-of-view obstacle avoidance laser radar transmission system, including a laser transmission system, a laser deflection system, a laser receiving system and a signal processing system;

[0006] The laser emission system is used to emit a large-field-of-view laser beam and a small-field-of-view laser beam;

[0007] The laser deflection system is located on the emitted laser light path and is used to scan the laser beam so that the emitted laser beam carries azimuth and pitch information;

[0008] The laser receiving system is located on the laser light path reflected by the target object, and is used to receive the large-field-of-view laser and the small-field-of-view laser beam reflected by the target object;

[0009] The signal processing system is located on the optical path of the emitted large field of view laser and small field of view laser and on the optical path of the reflected large field of view laser and small field of view laser, and is used to record the emission signals of the emitted large field of view laser and small field of view laser beams and the echo signals of the reflected large field of view laser and small field of view laser beams.

[0010] Furthermore, the laser emission system includes a laser fiber switch, a beam splitting component and a fiber collimator array.

[0011] The optical fiber switch, beam splitting assembly and optical fiber collimator array are sequentially located on the optical path of the laser emitting large field of view laser and small field of view laser;

[0012] The beam splitting assembly includes a first fiber beam splitter and a second fiber beam splitter, the first fiber beam splitter and the second fiber beam splitter are respectively located on different optical channels of the fiber switch transmission, and the fiber collimator array is located on the exit optical paths of the first fiber beam splitter and the second fiber beam splitter.

[0013] Further, the laser is a high-frequency pulse laser;

[0014] The optical fiber switch is a 1×2 prism optical switch, which is used to switch the optical channels of the first optical fiber beam splitter and the second optical fiber beam splitter.

[0015] The first optical fiber beam splitter is a large field of view beam splitter, which is used to split the light beam into N beams;

[0016] The second optical fiber beam splitter is a small field of view beam splitter, which is used to split the light beam into M beams, where M is less than N.

[0017] The optical fiber collimator array is used to collimate the sub-beams of the first optical fiber beam splitter and the second optical fiber beam splitter.

[0018] Furthermore, the first optical fiber beam splitter and the second optical fiber beam splitter both include a delay device, and the delay device is used to delay the laser beam split by the first optical fiber beam splitter or the second optical fiber beam splitter at equal intervals.

[0019] Further, the laser deflection system includes a laser deflection mirror and a beam reflection mirror;

[0020] The laser deflection mirror is located on the outgoing light path of the optical fiber collimator array, and the beam reflector is located on the outgoing light path of the laser deflection mirror and reflects the laser onto the target object;

[0021] Furthermore, the laser receiving system includes a return light receiving system, a beam deflecting mirror and a detector;

[0022] The return light receiving system comprises a large field of view receiving optical system and a small field of view receiving optical system, both of which are located on the reflected light path of the target object, and the beam deflection mirror is located on the outgoing light path of the large field of view receiving optical system and the small field of view receiving optical system;

[0023] The detector is located on the outgoing light path of the beam deflection mirror;

[0024] The signal output end of the detector is electrically connected to the signal processing system.

[0025] The large-field-of-view receiving optical system is used to receive the large-field-of-view scanning light beam echo;

[0026] The small-field-of-view receiving optical system is used to receive the small-field-of-view scanning light beam echo;

[0027] Further, the detector is an APD detector;

[0028] Furthermore, the material of the detector is Si, InGaAs, or InP;

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1) The laser deflection system of the present invention includes a laser deflection mirror and a beam reflector, which, as a beam scanning device, improves the reliability of the obstacle avoidance radar and significantly reduces the volume of the system;

[0031] 2) The laser emission system of the present invention includes a laser, a fiber switch, a first fiber beam splitter, a second fiber beam splitter, and a fiber collimator array. The laser repetition frequency is increased several times by parallel beam scanning of the first fiber beam splitter and the second fiber beam splitter, which significantly increases the point cloud density and enables the detection of long-distance fine obstacles.

[0032] 3) The laser receiving system in the present invention includes a large field of view receiving optical system, a small field of view receiving optical system, a beam deflection mirror and a detector. It adopts a dual field of view scanning method of the large field of view receiving optical system and the small field of view receiving optical system, which can not only quickly detect large obstacles, but also use a small field of view scanning method to perform fine detection of the area directly in front. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following drawings are only used to illustrate and explain the present invention, and are not used to limit the scope of the present invention, wherein:

[0034] Figure 1 : The schematic diagram of the radar system of the present invention;

[0035] Figure 2 : Working principle diagram of the radar system of the present invention;

[0036] Figure 3 : Schematic diagram of the laser receiving system of the present invention;

[0037] In the figure: 101-laser emitting system; 102-laser deflection system; 103-laser receiving system; 104-signal processing system; 105-target; 201-laser; 202-fiber switch; 203-first fiber beam splitter; 204-second fiber beam splitter; 205-fiber collimator array; 206-laser deflection mirror; 207-beam reflector; 301-large field of view receiving optical system; 302-small field of view receiving optical system; 303-beam deflection mirror; 304-detector. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution, design method and advantages of the present invention clearer, the present invention is further described in detail by specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] like Figure 1-Figure 3 As shown, the present invention provides a dual-field-of-view obstacle avoidance laser radar transmission system, characterized in that the system comprises: a laser transmission system 101, a laser deflection system 102, a laser receiving system 103 and a signal processing system 104;

[0040] The laser emitting system 101 is used to emit a large-field-of-view laser beam and a small-field-of-view laser beam;

[0041] The laser deflection system 102 is located on the emitted laser light path and is used to scan the laser beam so that the emitted laser beam carries azimuth and pitch information;

[0042] The laser receiving system 103 is located on the laser light path reflected by the target object, and is used to receive the large-field-of-view laser and the small-field-of-view laser beam reflected by the target object 105;

[0043] The signal processing system 104 is located on the optical path of the emitted large field of view laser and small field of view laser and the optical path of the reflected large field of view laser and small field of view laser, and is used to record the emission signal of the emitted large field of view laser and small field of view laser beam and the echo signal of the reflected large field of view laser and small field of view laser beam;

[0044] Furthermore, the laser emission system 101 includes a laser 201, a fiber switch 202, a beam splitting assembly and a fiber collimator array 205.

[0045] The optical fiber switch 202, the beam splitting assembly and the optical fiber collimator array 205 are sequentially located on the optical path of the laser 201 emitting the large field of view laser and the small field of view laser;

[0046] The beam splitting assembly includes a first optical fiber beam splitter 203 and a second optical fiber beam splitter 204, wherein the first optical fiber beam splitter 203 and the second optical fiber beam splitter 204 are respectively located on different optical channels transmitted by the optical fiber switch 202, and the optical fiber collimator array 205 is located on the outgoing optical paths of the first optical fiber beam splitter 203 and the second optical fiber beam splitter 204;

[0047] Further, the laser 201 is a high-frequency pulse laser for emitting a laser beam;

[0048] The optical fiber switch 202 is a 1×2 prism optical switch, which is used to switch the optical channels of the first optical fiber beam splitter 203 and the second optical fiber beam splitter 204 .

[0049] The first optical fiber beam splitter 203 is a large-field beam splitter, which is used to split the light beam into N beams;

[0050] The second optical fiber beam splitter 204 is a small field of view beam splitter, which is used to split the light beam into M beams, where M<N;

[0051] The optical fiber collimator array 205 is used to collimate the sub-beams of the first optical fiber beam splitter 203 and the second optical fiber beam splitter 204;

[0052] Furthermore, the first optical fiber beam splitter 203 and the second optical fiber beam splitter 204 both include a delay device, and the delay device is used to delay the laser beam split by the first optical fiber beam splitter 203 or the second optical fiber beam splitter 204 at equal intervals.

[0053] It should be noted that the first optical fiber beam splitter 203 and the second optical fiber beam splitter 204 both include a delay device having an optical delay function.

[0054] The first optical fiber beam splitter 203 is used to delay the N sub-beams at equal intervals, and the delay time is 1 / N of the emission period of the laser 201;

[0055] The second optical fiber beam splitter 204 is used to delay the M sub-beams at equal intervals, and the delay time is 1 / M of the emission period of the laser 201;

[0056] The delay devices of the first optical fiber beam splitter 203 and the second optical fiber beam splitter 204 are optical fiber delay devices or mechanical delay devices;

[0057] Further, the laser deflection system 102 includes a laser deflection mirror 206 and a beam reflection mirror 207;

[0058] The laser deflection mirror 206 is located on the outgoing light path of the fiber collimator array 205, and the beam reflector 207 is located on the outgoing light path of the laser deflection mirror 206 and reflects the laser beam onto the target object 105;

[0059] Further, the laser receiving system 103 includes a return light receiving system, a beam deflecting mirror 303 and a detector 304;

[0060] The return light receiving system includes a large field of view receiving optical system 301 and a small field of view receiving optical system 302, both of which are located on the reflected light path of the target object 105, and the beam deflection mirror 303 is located on the outgoing light path of the large field of view receiving optical system 301 and the small field of view receiving optical system 302;

[0061] The detector 304 is located on the outgoing light path of the beam deflection mirror 303;

[0062] The signal output end of the detector 304 is electrically connected to the signal processing system 104.

[0063] The large-field-of-view receiving optical system 301 is used to receive the large-field-of-view scanning beam echo;

[0064] The small-field-of-view receiving optical system 302 is used to receive the small-field-of-view scanning beam echo;

[0065] Further, the detector 304 is an APD detector;

[0066] Further, the material of the detector 304 is Si, InGaAs, or InP;

[0067] It should be noted that the material of the detector 304 is related to the wavelength emitted by the laser 201, and is generally Si, InGaAs, InP, etc.;

[0068] Working process: The high repetition rate laser 201 emits a beam of pulsed laser, which is then split by the first fiber beam splitter 203 and the second fiber beam splitter 204 into multiple beams of ultra-short laser pulses. The sub-beams of the first fiber beam splitter 203 and the second fiber beam splitter 204 are collimated by the fiber collimator array 205. The laser deflection mirror 206 and the beam reflector 207 scan the laser beam so that the emitted laser beam carries azimuth and pitch information. When the laser is projected onto the target 105, diffuse reflection occurs. The laser receiving system 103 receives the diffusely reflected light, and calculates the distance information of the target by measuring the flight time of the laser beam in the air. The three-dimensional perception of the space is completed by accurately measuring the distance of each point.

[0069] The present invention uses a laser deflection mirror 206 and a beam reflector 207 to scan the laser beam, and its reliability is greatly improved compared with a mechanical rotating device. The use of large and small dual fields of view can not only achieve large field of view detection, but also detect fine targets such as cables, and can replace the existing helicopter obstacle avoidance system.

[0070] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A dual-field-of-view obstacle avoidance laser radar transmission system, characterized in that: The system comprises: a laser emitting system (101), a laser deflection system (102), a laser receiving system (103) and a signal processing system (104); The laser emission system (101) is used to emit a large-field-of-view laser beam and a small-field-of-view laser beam; The laser deflection system (102) is located on the emitted laser light path and is used to scan the laser beam so that the emitted laser beam carries azimuth and pitch information; The laser receiving system (103) is located on the laser light path reflected by the target object, and is used to receive the large-field-of-view laser and the small-field-of-view laser beam reflected by the target object (105); A signal processing system (104) is located on the optical path of the emitted large field of view laser and small field of view laser and on the optical path of the reflected large field of view laser and small field of view laser, and is used to record the emission signals of the emitted large field of view laser and small field of view laser beams and the echo signals of the reflected large field of view laser and small field of view laser beams; The laser emission system (101) comprises a laser (201), an optical fiber switch (202), a beam splitting component and an optical fiber collimator array (205). The optical fiber switch (202), the beam splitting assembly and the optical fiber collimator array (205) are sequentially located on the optical paths of the laser (201) for emitting the large-field-of-view laser and the small-field-of-view laser; The beam splitting assembly comprises a first optical fiber beam splitter (203) and a second optical fiber beam splitter (204), wherein the first optical fiber beam splitter (203) and the second optical fiber beam splitter (204) are respectively located on different optical channels transmitted by the optical fiber switch (202), and the optical fiber collimator array (205) is located on the exit optical paths of the first optical fiber beam splitter (203) and the second optical fiber beam splitter (204); The laser deflection system (102) comprises a laser deflection mirror (206) and a beam reflection mirror (207); The laser deflection mirror (206) is located on the outgoing light path of the optical fiber collimator array (205), and the beam reflection mirror (207) is located on the outgoing light path of the laser deflection mirror (206) and reflects the laser onto the target object (105).

2. A dual-field-of-view obstacle avoidance laser radar transmitting system according to claim 1, characterized in that: The laser (201) is a high-frequency pulse laser; The optical fiber switch (202) is a 1×2 prism optical switch, used for switching the optical channels of the first optical fiber beam splitter (203) and the second optical fiber beam splitter (204); The first optical fiber beam splitter (203) is a large-field-of-view beam splitter, which is used to split the light beam into N beams; The second optical fiber beam splitter (204) is a small field of view beam splitter, which is used to split the light beam into M beams, where M<N; The optical fiber collimator array (205) is used to collimate the sub-beams of the first optical fiber beam splitter (203) and the second optical fiber beam splitter (204).

3. A dual-field-of-view obstacle avoidance laser radar transmitting system according to claim 1, characterized in that: The first optical fiber beam splitter (203) and the second optical fiber beam splitter (204) both comprise a delay device, and the delay device is used to delay the laser beam split by the first optical fiber beam splitter (203) or the second optical fiber beam splitter (204) at equal intervals.

4. A dual-field-of-view obstacle avoidance laser radar transmitting system according to claim 1, characterized in that: The laser receiving system (103) comprises a return light receiving system, a beam deflecting mirror (303) and a detector (304); The return light receiving system comprises a large field of view receiving optical system (301) and a small field of view receiving optical system (302), wherein the large field of view receiving optical system (301) and the small field of view receiving optical system (302) are both located on a reflected light path of the target object (105), and the light beam deflection mirror (303) is located on an outgoing light path of the large field of view receiving optical system (301) and the small field of view receiving optical system (302); The detector (304) is located on the outgoing light path of the beam deflection mirror (303); The signal output end of the detector (304) is electrically connected to the signal processing system (104). The large-field-of-view receiving optical system (301) is used to receive the large-field-of-view scanning light beam echo; The small-field-of-view receiving optical system (302) is used to receive the small-field-of-view scanning light beam echo.

5. A dual-field-of-view obstacle avoidance laser radar transmitting system according to claim 4, characterized in that: The detector (304) is an APD detector.

6. A dual-field-of-view obstacle avoidance laser radar transmitting system according to claim 4, characterized in that: The material of the detector (304) is Si, InGaAs, or InP.

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