CN210155332U - Distributed laser radar - Google Patents
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- CN210155332U CN210155332U CN201920631099.3U CN201920631099U CN210155332U CN 210155332 U CN210155332 U CN 210155332U CN 201920631099 U CN201920631099 U CN 201920631099U CN 210155332 U CN210155332 U CN 210155332U
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Abstract
The utility model discloses a distributing type laser radar. This distributed lidar includes: the device comprises a light generating unit, an information processing unit and a plurality of detection scanning units; the light generating unit is used for generating frequency-modulated continuous waves and primarily splitting the frequency-modulated continuous waves into the detection scanning units; each detection scanning unit is used for splitting the primarily split frequency-modulated continuous wave again to form a detection beam and a reference beam, transmitting the detection beam and receiving an echo beam reflected by a target object in a target area, and determining related information of the target area according to the reference beam and the echo beam; the information processing unit is used for integrating the relevant information of each target area to obtain a point cloud picture of the peripheral area of the distributed laser radar. The embodiment of the utility model provides a technical scheme can strengthen the detection real-time of the target object in the target area, improves the precision of testing the speed simultaneously.
Description
Technical Field
The embodiment of the utility model provides a relate to laser detection technical field, especially relate to a distributed laser radar.
Background
The laser radar is a radar system that emits a laser beam to detect a characteristic quantity such as a position and a velocity of a target object. The working principle of the laser radar is as follows: the method comprises the steps of transmitting a detection signal (laser beam) to a target object, comparing a received signal (target echo or echo signal) reflected from the target object with the transmitted signal, and carrying out appropriate processing to obtain relevant information of the target object, such as parameters of target distance, direction, height, speed, posture, even shape and the like, so as to detect, track and identify the target object.
Currently, lidar systems are typically pulsed lidar which determine the range of a target object by measuring the time of pulse propagation. When the laser radar is applied to a vehicle-mounted system, the speed and the moving direction of a target object need to be measured in real time, more emergency processing time can be given to a vehicle, and the accident volume is reduced. However, the existing pulse laser radar generally finds the movement speed of the target object through multi-frame data, so that the laser radar is poor in real-time performance and low in speed measurement accuracy.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a distributed laser radar to the reinforcing improves the precision of testing the speed to the detection real-time of target object simultaneously.
The embodiment of the utility model provides a distributed laser radar, this distributed laser radar includes: the device comprises a light generating unit, an information processing unit and a plurality of detection scanning units;
the light ray generating unit is used for generating frequency-modulated continuous waves and primarily splitting the frequency-modulated continuous waves into the detection scanning units;
each detection scanning unit is used for splitting the primarily split frequency-modulated continuous wave again to form a detection beam and a reference beam, transmitting the detection beam and receiving an echo beam reflected by a target object in a target area, and determining related information of the target area according to the reference beam and the echo beam;
the information processing unit is used for integrating the relevant information of each target area to obtain a point cloud picture of the peripheral area of the distributed laser radar;
wherein the related information of the target area comprises at least one of the orientation, the speed magnitude and the moving direction of the target object in the target area.
Furthermore, the light generating unit comprises a laser subunit, an intensity modulating subunit, a continuous frequency modulation signal source and a signal amplifying subunit;
the laser subunit is used for emitting a single-frequency light beam, and the single-frequency light beam is incident to the intensity modulation subunit;
the intensity modulation subunit is used for carrying out amplitude modulation on the single-frequency light beam under the driving of the continuous frequency modulation signal source to form an initial frequency modulation continuous wave;
and the signal amplification subunit is used for increasing the power of the initial frequency-modulated continuous wave to form the frequency-modulated continuous wave before primary beam splitting.
Further, the laser subunit includes a single-frequency polarization-maintaining laser, the intensity modulation subunit includes a polarization-maintaining lithium niobate intensity modulator, the continuous frequency modulation signal source includes a chirp signal source, and the signal amplification subunit includes a polarization-maintaining fiber amplifier.
Furthermore, the detection scanning unit comprises a light ray transmitting and receiving unit and a control processing unit;
the light transmitting and receiving unit is used for splitting the primarily split frequency-modulated continuous waves again to form a detection beam and a reference beam, transmitting the detection beam and receiving an echo beam reflected by a target object in a target area;
the control processing unit is used for determining the related information of the target area according to the reference beam and the echo beam.
Furthermore, the light transmitting and receiving unit comprises a beam splitting subunit, a detection signal transmitting subunit, an echo signal receiving subunit and a reference signal processing subunit;
the beam splitting subunit is used for splitting the primarily split frequency-modulated continuous wave into a detection beam and a reference beam according to a preset intensity ratio; wherein the intensity of the probe beam is greater than the intensity of the reference beam;
the detection signal transmitting subunit is used for transmitting and transmitting the detection light beam;
the echo signal receiving subunit is used for receiving the echo light beam;
the reference signal processing subunit is used for frequency shifting the reference beam;
the control processing unit is used for determining the related information of the target object according to the echo light beam and the reference light beam after frequency shift.
Further, the optical axis of the probe signal transmitting subunit and the optical axis of the echo signal receiving subunit are coaxially arranged.
Further, the beam splitting sub-unit comprises a polarization-preserving beam splitter, and the reference signal processing sub-unit comprises a polarization-preserving acousto-optic frequency shifter;
the polarization-maintaining circulator comprises a first port, a second port and a third port; the detection signal transmitting subunit comprises an optical path between the first port and the second port, and the echo signal receiving subunit comprises an optical path between the second port and the third port.
Furthermore, the detection signal transmitting subunit further comprises a beam expanding and collimating subunit and a two-dimensional scanning subunit;
the beam expanding and collimating subunit is used for expanding and collimating the detection beam emitted by the second port;
the two-dimensional scanning subunit is used for deflecting the expanded and collimated detection beam on a first plane and a second plane; the first plane intersects the second plane.
Further, the two-dimensional scanning subunit includes a combination of a horizontal prism and a vertical prism, a combination of a rotating prism and a mechanical micro-vibration mirror, a combination of a rotating prism and a one-dimensional MEMS scanning mirror, a combination of a one-dimensional MEMS scanning mirror and a one-dimensional mechanical micro-vibration mirror, a two-dimensional MEMS scanning mirror or a two-dimensional mechanical vibration mirror.
Furthermore, the control processing unit comprises a coherent processing subunit, a photoelectric conversion subunit, an analog-to-digital conversion subunit and an information acquisition subunit;
the coherent processing subunit is used for mixing the echo light beam with the reference light beam and outputting a light beam to be processed;
the photoelectric conversion subunit is used for converting the light beam to be processed into an analog electric signal;
the analog-to-digital conversion subunit is used for converting the analog electric signal into a digital electric signal;
the information acquisition subunit is used for acquiring the related information of the target object according to the digital electric signal.
Further, the coherent processing subunit includes a polarization maintaining coupler, the photoelectric conversion subunit includes a balanced detector, and the information acquisition subunit includes a field programmable gate array.
The embodiment of the utility model provides a laser radar, this laser radar includes light production unit, information processing unit and a plurality of detection scanning unit; the light ray generating unit is used for generating frequency-modulated continuous waves and primarily splitting the frequency-modulated continuous waves into the detection scanning units; each detection scan is used for splitting the primarily split frequency-modulated continuous wave again to form a detection beam and a reference beam, transmitting the detection beam and receiving an echo beam reflected by a target object in a target area, and determining related information of the target area according to the reference beam and the echo beam; the information processing unit is used for integrating the relevant information of each target area to obtain a point cloud picture of the peripheral area of the distributed laser radar. The target object in the target area is detected in real time based on the frequency modulation continuous wave, so that the target object can be accurately measured; meanwhile, the movement direction and the speed of the target object can be accurately obtained by combining a coherent detection mode and utilizing the Doppler principle, so that the speed measurement precision can be improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a distributed laser radar provided by an embodiment of the present invention;
fig. 2 is a schematic structural diagram of another distributed lidar provided by an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another distributed laser radar provided by an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a detection scanning unit in the distributed laser radar provided by the embodiment of the present invention;
fig. 5 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention;
fig. 6 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention;
fig. 7 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention;
fig. 8 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of a distributed laser radar provided by an embodiment of the present invention. Referring to fig. 1, the distributed lidar 10 includes: a light generating unit 110, an information processing unit 120, and a plurality of detection scanning units 130; the light generating unit 110 is configured to generate a frequency modulated continuous wave, and primarily split the frequency modulated continuous wave into the detection scanning units 130; each probe scanning unit 130 is configured to split the primarily split frequency-modulated continuous wave again to form a probe beam and a reference beam, emit the probe beam and receive an echo beam reflected by a target object in a target area, and determine relevant information of the target area according to the reference beam and the echo beam; the information processing unit 120 is configured to integrate relevant information of each target area to obtain a point cloud image of a peripheral area of the distributed laser radar; wherein the related information of the target area comprises at least one of the orientation, the speed magnitude and the moving direction of the target object in the target area.
The light generating unit 110 and the information processing unit 120 may be integrated. For example, when the distributed lidar is applied to an on-vehicle system, the light generation unit 110 and the information processing unit 120 may be integrated into the on-vehicle lidar switch 11.
Illustratively, the number of the detection scanning units 130 is 4, and the light generation unit 110 in the vehicle-mounted laser radar switch 11 generates a frequency-modulated continuous wave and divides the frequency-modulated continuous wave into four beams as light sources of the detection scanning units 130 of the distributed laser radar 10; each detection scanning unit 130 respectively scans and detects the corresponding target area and transmits the scanning detection information to the vehicle-mounted laser radar switch 11; the information processing unit 120 in the vehicle-mounted lidar switch 11 receives the relevant information from each of the probe scanning units 130, and integrates the received relevant information to obtain a cloud point map of the surrounding environment of the distributed lidar 10.
For example, the scout scan process of the scout scan unit 130 on the target area may include: dividing the primarily divided frequency-modulated continuous wave into two beams again, wherein one beam is used as a detection beam, and the other beam is used as a reference beam; emitting a probe beam to a target area, wherein the target area comprises a plurality of target objects, and a beam reflected by the target objects in the target area is called an echo beam; by scanning the probe beam within the target area, information about the target area, including at least one of the number, size, orientation, velocity, and direction of motion of the target object, can be determined from each reference beam and the corresponding echo beam.
It should be noted that the target region is understood as a region that can be detected and scanned by each detection scanning unit 120, and the target object is determined by actual environmental conditions, which is not limited by the embodiments of the present invention.
It should be noted that fig. 1 only shows the number of the detection scanning units 130 as 4 by way of example, but the present invention is not limited to the distributed lidar 10 provided by the embodiment of the present invention. In other embodiments, the number of the detection scanning units 130 may be set according to the actual requirement of the distributed laser radar 10, which is not limited by the embodiment of the present invention.
The embodiment of the utility model provides a distributed laser radar 10 surveys based on frequency modulation continuous wave, can realize the real-time accurate measurement to the relevant information of target object; meanwhile, the speed and the movement direction of the target object can be accurately measured in real time by combining a coherent detection mode and utilizing a Doppler principle; when the laser radar is applied to a vehicle-mounted system, the surrounding environment of an automobile can be accurately monitored in real time, and the safety guarantee performance in the driving process is improved. In addition, by providing the light generation unit 110 to provide a light source for the plurality of detection scanning units 130, the degree of integration of the distributed lidar 10 can be improved, which is beneficial to reducing the number of components and the overall volume of the distributed lidar 10.
Optionally, fig. 2 is a schematic structural diagram of another distributed lidar according to an embodiment of the present invention. Referring to fig. 2, the light generating unit 110 includes a laser subunit 111, an intensity modulating subunit 112, a continuous frequency modulation signal source 113, and a signal amplifying subunit 114; the laser subunit 111 is configured to emit a single-frequency light beam, and the single-frequency light beam is incident to the intensity modulation subunit 112; the intensity modulation subunit 112 is configured to perform amplitude modulation on the single-frequency light beam under the driving of the continuous frequency modulation signal source 113, so as to form an initial frequency modulation continuous wave; the signal amplification subunit 114 is configured to increase the power of the initial frequency-modulated continuous wave to form the frequency-modulated continuous wave before the initial beam splitting.
Wherein, the laser subunit 111 emits a single-frequency laser beam; the single-frequency laser beam is incident to the intensity modulation subunit 112, and the parameters such as the light intensity and the phase of the single-frequency laser beam incident to the intensity modulation subunit 112 are modulated by using the continuous frequency modulation signal source 113 to obtain an initial frequency modulation continuous wave; the initial frequency-modulated continuous wave is incident to the signal amplification subunit 114, and the signal amplification subunit 114 further increases the intensity of the initial frequency-modulated continuous wave to form the frequency-modulated continuous wave before the primary beam splitting, which is favorable for meeting the subsequent detection requirement. It should be noted that the amplitude, power and intensity are all in positive correlation.
The light generating unit 110 employs an external modulation mode, that is, a modulation signal is loaded after a single-frequency laser beam is formed, and since the external modulation mode does not have additional frequency modulation of the laser subunit 111, combined secondary distortion can be effectively overcome.
Illustratively, the intensity modulation subunit 112 may modulate the single-frequency laser beam based on an electro-optic effect, a magneto-optic effect, an acousto-optic effect, or other effects, which is not limited by the embodiment of the present invention.
Illustratively, continuous frequency modulated signal source 113 may be a chirped continuous signal source, i.e., a signal whose frequency varies linearly with time.
Optionally, with continued reference to fig. 2, laser subunit 111 comprises a single-frequency polarization-maintaining laser, intensity modulation subunit 112 comprises a lithium polarization-maintaining niobate intensity modulator, chirp signal source 113 comprises a chirp signal source, and signal amplification subunit 114 comprises a polarization-maintaining fiber amplifier.
With such an arrangement, it is favorable to ensure that the polarization states of the light beams of the transmission nodes in the distributed laser radar 10 are all consistent, and it is favorable to ensure the detection accuracy.
The single-frequency polarization-maintaining laser generates a single-frequency polarization-maintaining laser beam, the chirp signal source drives the polarization-maintaining lithium niobate intensity modulator to modulate the single-frequency polarization-maintaining laser beam to form an initial frequency modulation continuous wave, and the initial frequency modulation continuous wave with a narrow line width and high power is formed after passing through the polarization-maintaining optical fiber amplifier.
For example, the single-frequency polarization maintaining laser may be a single-frequency polarization maintaining fiber laser, a single-frequency polarization maintaining semiconductor laser, or other types of single-frequency polarization maintaining lasers known to those skilled in the art, and the embodiment of the present invention is not limited thereto.
For example, the wavelength band of the single-frequency polarization maintaining laser may be 1.064 μm, 1.55 μm, 2 μm, or other wavelength bands known to those skilled in the art, and the embodiment of the present invention is not limited thereto.
Illustratively, the frequency of a signal from a chirp signal source varies with time, and the frequency variation due to modulation at the leading and trailing edges of a pulse causes the signal to be spectrally broadened, and is described by a chirp coefficient (also called a line width broadening factor), which may be linear or non-linear.
Illustratively, a lithium-polarization-maintaining niobate intensity modulator employs the electro-optic effect to amplitude modulate the incipient light beam.
The polarization maintaining fiber amplifier can amplify the power of the initial frequency modulation continuous wave to form a narrow-linewidth high-power frequency modulation continuous wave. Illustratively, the polarization maintaining Fiber Amplifier may be an Erbium-Doped Fiber Amplifier (EDFA), a praseodymium-Doped Fiber Amplifier (PDFA), a Niobium-Doped Fiber Amplifier (NDFA), an Ytterbium-Doped Fiber Amplifier (YDFA), or other types of Fiber amplifiers, which are not limited in this respect.
Thus, the light generating unit 110 can generate and amplify the frequency modulated continuous wave.
Optionally, fig. 3 is a schematic structural diagram of another distributed laser radar provided in the embodiment of the present invention. Referring to fig. 3, the detection scanning unit 130 includes a light transmitting and receiving unit 131 and a control processing unit 132; the light transmitting and receiving unit 131 is configured to split the primarily split frequency-modulated continuous wave again to form a probe beam and a reference beam, and to transmit the probe beam and receive an echo beam reflected by a target object in a target area; the control processing unit 132 is used for determining the relevant information of the target area according to the reference beam and the echo beam.
For one detecting and scanning unit 130, the light receiving and emitting unit 131 divides the primary split frequency-modulated continuous wave transmitted to the detecting and scanning unit 130 into two beams, one beam serving as a detecting beam and the other beam serving as a reference beam; the probe beam is emitted from the probe scanning unit 130 and irradiates a target area, the target area includes a plurality of target objects 20, and the echo beam reflected by the target objects 20 is received by the light transmitting and receiving unit 131 and transmitted to the control processing unit 132 together with the reference beam; the control processing unit 132 can determine the related information of the target object 20 in the target area according to the echo beam and the reference beam, and the detection mode can be understood as a coherent detection mode.
It should be noted that fig. 2 and fig. 3 each only exemplarily show that the number of the detection scanning units 130 is 2, but do not constitute a limitation to the distributed lidar 10 provided by the embodiment of the present invention. In other embodiments, the number of detecting scanning units 130 may be set according to the actual requirement of the distributed laser radar 10, which is not limited by the embodiment of the present invention.
The structure of the probe scanning unit 130 is exemplarily described below with reference to fig. 4 to 8.
Optionally, fig. 4 is a schematic structural diagram of a detection scanning unit in the distributed laser radar provided by the embodiment of the present invention. Referring to fig. 4, the light transmitting and receiving unit 131 includes a beam splitting subunit 311, a probe signal transmitting subunit 312, an echo signal receiving subunit 313, and a reference signal processing subunit 314; the beam splitting subunit 311 is configured to split the primarily split frequency-modulated continuous wave into a probe beam and a reference beam according to a preset intensity ratio; wherein the intensity of the probe beam is greater than the intensity of the reference beam; the probe signal transmitting subunit 312 is configured to transmit and transmit a probe beam; the echo signal receiving subunit 313 is configured to receive an echo light beam; the reference signal processing subunit 314 is configured to shift the frequency of the reference beam; the control processing unit 132 is used for determining the relevant information of the target object according to the echo light beam and the frequency-shifted reference light beam.
The scout scanning unit 130 uses a coherent detection method to accurately measure the speed and the moving direction of the target object 20.
For example, the predetermined intensity ratio of the probe beam to the reference beam may be 9:1, 8:2 or other suitable ratios, which may be satisfied with the detection and signal processing requirements, and the embodiment of the present invention does not limit this.
Alternatively, the optical axis of the probe signal transmitting subunit 312 and the optical axis of the echo signal receiving subunit 313 are coaxially arranged.
With this arrangement, the structure of the light transmitting and receiving unit 131 is simplified, the number of optical elements is reduced, and the space is saved, so that the number of elements and the occupied space in the detection scanning unit 130 are reduced, and the number of elements in the distributed laser radar 10 and the occupied space of the whole distributed laser radar 10 are reduced.
Optionally, fig. 5 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention. Referring to fig. 4 and 5, the splitting sub-unit 311 includes a polarization-preserving splitter 3111, and the reference signal processing sub-unit 314 includes a polarization-preserving acousto-optic frequency shifter 3141; further comprising a polarization maintaining circulator 315, the polarization maintaining circulator 315 comprising a first port 3151, a second port 3152 and a third port 3153; the probe signal transmitting subunit 312 includes an optical path between the first port 3151 and the second port 3152, and the echo signal receiving subunit 313 includes an optical path between the second port 3152 and the third port 3153.
The polarization maintaining beam splitter 3111 splits the frequency-modulated continuous wave into two beams according to a preset intensity ratio, the probe beam with higher intensity is emitted after passing through the first port 3151 and the second port 3152 of the polarization maintaining circulator 315, and the echo beam reflected by the target object 20 is incident to the polarization maintaining circulator 315 through the second port 3152 and is output through the third port 3153. The reference beam with a lower intensity is passed through the polarization-preserving acousto-optic frequency shifter 3141 (for example, the polarization-preserving acousto-optic frequency shifter 3141 is controlled by the driver 3142), and then compared with the echo beam in the control processing unit 130 to obtain the related information of the target object 20.
For example, the polarization maintaining circulator 315 may be a polarization maintaining fiber circulator, or may be a polarization maintaining circulator having a spatial structure formed by a polarization splitting prism, an 1/4 wave plate, and a 1/2 wave plate, or may be another type of polarization maintaining circulator, which is not limited in this embodiment of the present invention.
Optionally, with continued reference to fig. 4 and 5, the probe signal emitting subunit 313 further includes a beam expanding and collimating subunit 3161 and a two-dimensional scanning subunit 3162; the beam expanding and collimating subunit 3161 is configured to expand and collimate the probe beam emitted from the second port 3152; the two-dimensional scanning subunit 3162 is used for deflecting the expanded and collimated probe beam on a first plane and a second plane; the first plane intersects the second plane.
The beam expanding and collimating subunit 3161 and the two-dimensional scanning subunit 3162 may be collectively referred to as an optical system unit 316. The light beam emitted from the second port 3152 of the polarization maintaining circulator 315 passes through the beam expanding and collimating subunit 3161 and the two-dimensional scanning subunit 3162 and is emitted.
For example, the beam expanding and collimating subunit 3161 may include a beam expanding lens, a collimating lens, or other optical elements known to those skilled in the art, and the embodiments of the present invention are not limited thereto.
Optionally, the two-dimensional scanning subunit 3162 includes a combination of a horizontal prism and a vertical prism, a combination of a rotating prism and a mechanical micro-galvanometer, a combination of a rotating prism and a one-dimensional MEMS scanning mirror, a combination of a one-dimensional MEMS scanning mirror and a one-dimensional mechanical micro-galvanometer, a two-dimensional MEMS scanning mirror, or a two-dimensional mechanical galvanometer.
The horizontal prism, the vertical prism, the rotating prism, the mechanical micro-vibration mirror and the one-dimensional MEMS scanning mirror can be regarded as one-dimensional scanning mirrors, and the two one-dimensional scanning mirrors are combined to realize scanning of a two-dimensional space; or the two-dimensional scanning mirror is directly utilized to realize the scanning of the two-dimensional space so as to obtain the three-dimensional space coordinate of the target object; meanwhile, based on coherent detection and Doppler principle, the speed and the moving direction of the target object can be obtained. Therefore, the five-dimensional information detection of the target object can be realized, and the five-dimensional information detection system is strong in anti-interference performance, accurate in detection and high in sensitivity and is beneficial to providing higher safety guarantee for unmanned driving when being applied to a vehicle-mounted system.
In addition, the optical scanning system of the distributed laser radar 10 only needs to rotate the prism or the MEMS micro-vibrating mirror or the mechanical vibrating mirror, the laser transmitting and receiving lens and various control circuits do not need to rotate, and power is directly supplied to the circuits without other modes. Meanwhile, coherent detection is carried out by adopting frequency modulation continuous waves, and the periodic rotary scanning of the two-dimensional scanning subunit is combined, so that the distributed laser radar 10 can carry out uniform scanning on the whole detection scanning target area, and the scanning speed is uniform and the periodicity is stable.
Exemplarily, fig. 6 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention, fig. 7 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention, fig. 8 is a schematic structural diagram of another detection scanning unit in the distributed laser radar provided by the embodiment of the present invention, all showing an optional optical scanning system of the detection scanning unit 130, and this optical scanning system adopts a coaxial system.
The optical scanning system comprises, among other things, an optical fiber 301 (which can be understood as the second port 3152 of the polarization-maintaining circulator 315 in fig. 5), a collimating and receiving lens 302, and a two-dimensional scanning sub-unit, which comprises, in fig. 6 and 7, a first scanning mirror 303 and a second scanning mirror 304, and, in fig. 8, a two-dimensional scanning sub-unit, which comprises a two-dimensional scanning mirror 305. The collimating and receiving lens 302 collimates the polarization-maintaining circulator 315 output beam for transmission and converges and couples the received echo beams into the polarization-maintaining circulator 315.
Illustratively, in FIG. 6, first scanning mirror 303 is a first rotating prism and second scanning mirror 304 is a second rotating prism. The first rotating prism is rotated, laser is scanned in the vertical direction through a rotating corner and is shot on the side face (working face) of the second rotating prism, the second rotating prism reflects a laser beam out according to a set angle through rotation, the laser beam is scanned in the horizontal direction, and scanning in a certain angle in the vertical direction and the horizontal direction is realized through the two rotating prisms to form a planar array.
Illustratively, in fig. 7, the first scanning mirror 303 is a MEMS micro-galvanometer or a one-dimensional mechanical galvanometer, and the second scanning mirror 304 is a rotating prism. The laser is irradiated on the MEMS micro-vibrating mirror or the one-dimensional mechanical vibrating mirror, so that the laser scans in the vertical direction and is irradiated on the side surface (working surface) of the rotating prism, the rotating prism reflects the laser beam out according to a set angle through rotation, and the laser scans in the horizontal direction, so that the scanning in certain angles in the vertical direction and the horizontal direction is realized, and an area array is formed.
Illustratively, the two-dimensional scanning mirror 305 in fig. 8 is a two-dimensional MEMS scanning mirror, a two-dimensional mechanical galvanometer, or other types of two-dimensional scanning mirrors known to those skilled in the art, and the two-dimensional scanning mirror 305 can simultaneously scan in the horizontal and vertical directions to form an area array in the detection area.
It should be noted that fig. 6 and 7 only illustrate an exemplary combination of two one-dimensional scanning mirrors, but do not limit the distributed lidar 10 according to the embodiment of the present invention. In other embodiments, other types of one-dimensional scanning mirror combinations known to those skilled in the art may be further provided according to the actual requirements of the distributed laser radar 10 to implement two-dimensional scanning, which is not limited by the embodiments of the present invention.
Optionally, with continued reference to fig. 4 or fig. 5, the control processing unit 132 includes a coherent processing subunit 321, a photoelectric conversion subunit 322, an analog-to-digital conversion subunit 323, and an information acquisition subunit 324; the coherent processing subunit 321 is configured to mix the echo beam with the reference beam, and output a beam to be processed; the photoelectric conversion subunit 322 is configured to convert the light beam to be processed into an analog electrical signal; the analog-to-digital conversion subunit 323 is configured to convert the analog electrical signal into a digital electrical signal; the information acquiring subunit 324 is configured to acquire information related to the target object according to the digital electrical signal.
Thus, the reference signal and the echo signal are mixed, and after photoelectric conversion and analog-to-digital conversion, the information acquisition subunit 324 is used to perform corresponding algorithm processing, so that information such as two-dimensional coordinates, distance, motion direction, speed and the like of the target object can be output, and five-dimensional detection is realized.
It should be noted that the scanning detection unit 130 of the distributed lidar 10 may further include other components or assemblies known to those skilled in the art, such as a signal output unit 135, and the signal output unit 135 may be configured to output the five-dimensional information of the target object to a total control system or to a display interface, which is not limited by the embodiment of the present invention.
Optionally, with continued reference to fig. 4 or 5, the coherent processing subunit 321 includes a polarization maintaining coupler, the photoelectric conversion subunit 322 includes a balanced detector, and the information acquisition subunit 324 includes a field programmable gate array.
The echo signal and the frequency-shifted reference signal are mixed in the polarization-preserving coupler and then output, and the noise can be reduced by utilizing the balance detector, so that the detection precision and the sensitivity can be improved; then sampling by A/D (analog-to-digital conversion), and carrying out algorithm processing by using a field programmable gate array to obtain the related information of the target object.
It should be noted that fig. 1-5 only exemplarily show the signal transmission relationship among the components in distributed lidar 10, but do not constitute a limitation on the spatial relative position. In other embodiments, the relative positions between the components of distributed lidar 10 may be set according to actual requirements of distributed lidar 10, which is not limited by the embodiments of the present invention.
The embodiment of the utility model provides a distributed laser radar 10 realizes the real-time accurate measurement to the relevant information of the target object in the target area based on frequency modulation continuous wave laser coherent detection and Doppler principle; the five-dimensional information detection of the target object can be realized by combining a two-dimensional optical scanning system; when the device is used as a vehicle-mounted laser radar, after a target point cloud picture of the vehicle surrounding environment can be obtained by utilizing a plurality of detection scanning units, the target point cloud picture is transmitted to an information processing unit through a serial port and the like, the five-dimensional information of the vehicle surrounding environment can be obtained after the point cloud picture information of each detection scanning unit is integrated by the information processing unit, the information is high in accuracy and good in real-time performance, so that the high-accuracy wide-field-of-view range measurement of the vehicle surrounding environment target can be realized, and higher safety guarantee can be provided in the driving process.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (11)
1. A distributed lidar, comprising: the device comprises a light generating unit, an information processing unit and a plurality of detection scanning units;
the light ray generating unit is used for generating frequency-modulated continuous waves and primarily splitting the frequency-modulated continuous waves into the detection scanning units;
each detection scanning unit is used for splitting the primarily split frequency-modulated continuous wave again to form a detection beam and a reference beam, transmitting the detection beam and receiving an echo beam reflected by a target object in a target area, and determining related information of the target area according to the reference beam and the echo beam;
the information processing unit is used for integrating the relevant information of each target area to obtain a point cloud picture of the peripheral area of the distributed laser radar;
wherein the related information of the target area comprises at least one of the orientation, the speed magnitude and the moving direction of the target object in the target area.
2. The distributed lidar of claim 1, wherein the line generating unit comprises a laser subunit, an intensity modulation subunit, a continuous frequency modulation signal source, and a signal amplification subunit;
the laser subunit is used for emitting a single-frequency light beam, and the single-frequency light beam is incident to the intensity modulation subunit;
the intensity modulation subunit is used for carrying out amplitude modulation on the single-frequency light beam under the driving of the continuous frequency modulation signal source to form an initial frequency modulation continuous wave;
and the signal amplification subunit is used for increasing the power of the initial frequency-modulated continuous wave to form the frequency-modulated continuous wave before primary beam splitting.
3. The distributed lidar of claim 2, wherein the laser subunit comprises a single frequency polarization-maintaining laser, the intensity modulation subunit comprises a lithium polarization-maintaining niobate intensity modulator, the continuous frequency modulation signal source comprises a chirp signal source, and the signal amplification subunit comprises a polarization-maintaining fiber amplifier.
4. The distributed lidar of claim 1, wherein the probe scanning unit comprises a light transceiver unit and a control processing unit;
the light transmitting and receiving unit is used for splitting the primarily split frequency-modulated continuous waves again to form a detection beam and a reference beam, transmitting the detection beam and receiving an echo beam reflected by a target object in a target area;
the control processing unit is used for determining the related information of the target area according to the reference beam and the echo beam.
5. The distributed lidar of claim 4, wherein the light transmitting and receiving unit comprises a beam splitting subunit, a probe signal transmitting subunit, an echo signal receiving subunit, and a reference signal processing subunit;
the beam splitting subunit is used for splitting the primarily split frequency-modulated continuous wave into a detection beam and a reference beam according to a preset intensity ratio; wherein the intensity of the probe beam is greater than the intensity of the reference beam;
the detection signal transmitting subunit is used for transmitting and transmitting the detection light beam;
the echo signal receiving subunit is used for receiving the echo light beam;
the reference signal processing subunit is used for frequency shifting the reference beam;
the control processing unit is used for determining the related information of the target object according to the echo light beam and the reference light beam after frequency shift.
6. The distributed lidar of claim 5, wherein an optical axis of the probe signal transmitting subunit is disposed coaxially with an optical axis of the echo signal receiving subunit.
7. The distributed lidar of claim 6, wherein the beam splitting sub-unit comprises a polarization-preserving beam splitter, and wherein the reference signal processing sub-unit comprises a polarization-preserving acousto-optic frequency shifter;
the polarization-maintaining circulator comprises a first port, a second port and a third port; the detection signal transmitting subunit comprises an optical path between the first port and the second port, and the echo signal receiving subunit comprises an optical path between the second port and the third port.
8. The distributed lidar of claim 7, wherein the probe signal transmitting subunit further comprises a beam expanding collimating subunit and a two-dimensional scanning subunit;
the beam expanding and collimating subunit is used for expanding and collimating the detection beam emitted by the second port;
the two-dimensional scanning subunit is used for deflecting the expanded and collimated detection beam on a first plane and a second plane; the first plane intersects the second plane.
9. The distributed lidar of claim 8, wherein the two-dimensional scanning subunit comprises a combination of a horizontal prism and a vertical prism, a combination of a rotating prism and a mechanical galvanometer, a combination of a rotating prism and a one-dimensional MEMS scanning mirror, a combination of a one-dimensional MEMS scanning mirror and a one-dimensional mechanical galvanometer, a two-dimensional MEMS scanning mirror, or a two-dimensional mechanical galvanometer.
10. The distributed lidar of claim 4, wherein the control processing unit comprises a coherent processing subunit, a photoelectric conversion subunit, an analog-to-digital conversion subunit, and an information acquisition subunit;
the coherent processing subunit is used for mixing the echo light beam with the reference light beam and outputting a light beam to be processed;
the photoelectric conversion subunit is used for converting the light beam to be processed into an analog electric signal;
the analog-to-digital conversion subunit is used for converting the analog electric signal into a digital electric signal;
the information acquisition subunit is used for acquiring the related information of the target object according to the digital electric signal.
11. The distributed lidar of claim 10, wherein the coherent processing subunit comprises a polarization maintaining coupler, the optical-to-electrical conversion subunit comprises a balanced detector, and the information acquisition subunit comprises a field programmable gate array.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109991623A (en) * | 2019-04-30 | 2019-07-09 | 深圳市镭神智能系统有限公司 | A kind of distribution type laser radar |
| CN117347980A (en) * | 2023-12-04 | 2024-01-05 | 深圳市镭神智能系统有限公司 | Large-view-field laser radar and carrier |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109991623A (en) * | 2019-04-30 | 2019-07-09 | 深圳市镭神智能系统有限公司 | A kind of distribution type laser radar |
| CN117347980A (en) * | 2023-12-04 | 2024-01-05 | 深圳市镭神智能系统有限公司 | Large-view-field laser radar and carrier |
| CN117347980B (en) * | 2023-12-04 | 2024-03-12 | 深圳市镭神智能系统有限公司 | Large-view-field laser radar and carrier |
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