WO2022036714A1 - Laser ranging module, ranging device, and mobile platform - Google Patents

Abstract

A laser ranging module, a ranging device (100), and a mobile platform. The method comprises: continuously transmitting at least two laser pulse signals according to a preset time interval (S610); receiving return light pulse signals, and determining the time of reception of the return light pulse signals (S620); determining, in the return light pulse signals according to the preset time interval and the time of reception, effective return light pulse signals reflected by the at least two laser pulse signals by means of a measured object (S630); and determining a distance between the ranging device (100) and the measured object according to the time of reception of the effective return light pulse signals (S640). The at least two laser pulse signals are continuously transmitted, and the effective return light pulse signals in the return light pulse signals are extracted according to the time of reception of the return light pulse signals, so that crosstalk signals are effectively recognized and filtered, and the robustness and anti-interference capability of the ranging device (100) are improved.

Description

Laser ranging method, ranging device and movable platform technical field

Embodiments of the present invention relate to the technical field of ranging, and more particularly, to a laser ranging method, a ranging device, and a movable platform.

Background technique

Laser ranging devices such as three-dimensional point cloud detection systems such as lidar and laser rangefinders can measure the time of light travel between the ranging device and the measured object, that is, the time-of-flight (TOF) of light. ) to detect the distance from the detected object to the ranging device. This type of laser ranging device emits a beam of laser pulses from the transmitting end, which is reflected by the measured object, and the receiving end receives the reflected signal of the measured object to form a receiving pulse. Calculate the distance between the laser ranging device and the measured object.

In the above process, the receiving end of the laser ranging device will also receive the pulse signal reflected from the laser pulse not emitted by itself, that is, receive the interference signal. The phenomenon of interference is very common. For example, when two lidars work at the same time, the receiver of one lidar is likely to receive the laser pulses directly emitted by the other lidar, or receive the laser pulses emitted by the other lidar. reflected laser pulses. The interference signal will cause the lidar to be unable to effectively identify the interference information in the received pulse, so that it can calculate the wrong distance value, so that it cannot perform correct detection.

In view of the interference problem, most of the current laser ranging devices usually reduce stray light by improving the optical receiving system, but this method cannot effectively solve the problem of crosstalk, which greatly restricts the application of laser ranging devices in the fields of automatic driving, security, surveying and mapping. Applications.

SUMMARY OF THE INVENTION

A series of concepts in simplified form have been introduced in the Summary section, which are described in further detail in the Detailed Description section. The Summary of the Invention section of the present invention is not intended to attempt to limit the key features and essential technical features of the claimed technical solution, nor is it intended to attempt to determine the protection scope of the claimed technical solution.

In view of the deficiencies of the prior art, the first aspect of the embodiments of the present invention provides a laser ranging method, including:

Continuously emit at least two laser pulse signals at preset time intervals;

Receive the return light pulse signal, and determine the receiving time of the return light pulse signal;

According to the preset time interval and the receiving time, in the return light pulse signal, determine the effective return light pulse signal of the at least two laser pulse signals reflected by the measured object;

The distance between the distance measuring device and the measured object is determined according to the receiving time of the effective return light pulse signal.

A second aspect of the embodiments of the present invention provides a distance measuring device, including:

a transmitting circuit for continuously transmitting at least two laser pulse signals according to a preset time interval;

The receiving circuit is used to receive the optical pulse signal;

a sampling circuit for determining the receiving time of the return light pulse signal;

an arithmetic circuit, configured to determine, in the return light pulse signal, the effective return light pulse signal reflected by the object to be measured from the at least two laser pulse signals according to the preset time interval and the receiving time, and according to the returned light pulse signal The receiving time of the effective return light pulse signal determines the distance between the distance measuring device and the measured object.

A third aspect of the embodiments of the present invention provides a movable platform, the movable platform includes a movable platform body and the above-mentioned distance measuring device, and the distance measuring device is mounted on the movable platform body.

The laser ranging method, the ranging device and the movable platform according to the embodiments of the present invention transmit at least two laser pulse signals continuously, and extract the effective return light pulse signal from the return light pulse signal according to the receiving time of the return light pulse signal, so as to effectively It can identify and filter interfering signals to improve the robustness and anti-interference ability of the ranging device.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative labor.

FIG. 1 is a schematic frame diagram of a distance measuring device according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an embodiment in which a distance measuring device according to an embodiment of the present invention adopts a coaxial optical path;

3 is a schematic diagram of a scanning pattern of a laser radar according to an embodiment of the present invention;

Figure 4 is a schematic diagram of laser ranging based on the time of flight of light;

5 is a schematic diagram of an effective return light pulse signal and an interference signal received by the ranging device;

6 is a schematic flowchart of a laser ranging method according to an embodiment of the present invention;

7 is a schematic diagram of an effective return light pulse signal and an interference signal received by a ranging device in a laser ranging method according to an embodiment of the present invention;

FIG. 8 is a flowchart of an algorithm for determining an effective return light pulse signal and an interference signal in a laser ranging method according to an embodiment of the present invention.

detailed description

In order to make the objects, technical solutions and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of the embodiments of the present invention, and it should be understood that the present invention is not limited by the example embodiments described herein. Based on the embodiments of the present invention described in the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details. In other instances, some technical features known in the art have not been described in order to avoid obscuring the present invention.

It should be understood that the present invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the/the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the terms "compose" and/or "include", when used in this specification, identify the presence of stated features, integers, steps, operations, elements and/or components, but do not exclude one or more other The presence or addition of features, integers, steps, operations, elements, parts and/or groups. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

For a thorough understanding of the present invention, detailed structures will be presented in the following description in order to explain the technical solutions proposed by the present invention. Alternative embodiments of the present invention are described in detail below, however, the invention is capable of other embodiments in addition to these detailed descriptions.

The laser ranging method provided by the various embodiments of the present invention can be applied to a ranging device, and the ranging device can be an electronic device such as a laser radar or a laser ranging device. In one embodiment, the ranging device is used to sense external environmental information, for example, distance information, orientation information, reflection intensity information, speed information and the like of environmental objects. The ranging device can detect the distance from the detected object to the ranging device by measuring the time of light propagation between the ranging device and the detected object, that is, the time-of-flight (TOF) of light.

For ease of understanding, the working process of ranging will be described by way of example below with reference to the ranging apparatus 100 shown in FIG. 1 .

As shown in FIG. 1 , the ranging apparatus 100 may include a transmitting circuit 110 , a receiving circuit 120 , a sampling circuit 130 and an arithmetic circuit 140 .

The transmit circuit 110 may transmit a sequence of optical pulses (eg, a sequence of laser pulses). The receiving circuit 120 can receive the optical pulse sequence reflected by the detected object, and perform photoelectric conversion on the optical pulse sequence to obtain an electrical signal, which can be output to the sampling circuit 130 after processing the electrical signal. The sampling circuit 130 may sample the electrical signal to obtain a sampling result. The arithmetic circuit 140 may determine the distance between the distance measuring device 100 and the detected object based on the sampling result of the sampling circuit 130 .

Optionally, the distance measuring device 100 may further include a control circuit 150, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.

It should be understood that although the distance measuring device shown in FIG. 1 includes a transmitting circuit, a receiving circuit, a sampling circuit and an arithmetic circuit for emitting a beam of light for detection, the embodiment of the present application is not limited to this, the transmitting circuit The number of any one of the receiving circuits, sampling circuits, and arithmetic circuits may also be at least two, for emitting at least two light beams in the same direction or in different directions respectively; wherein, the at least two light beam paths can be simultaneously The ejection can also be ejected at different times. In one example, the light-emitting chips in the at least two emission circuits are packaged in the same module. For example, each emitting circuit includes one laser emitting chip, and the dies in the laser emitting chips in the at least two emitting circuits are packaged together and accommodated in the same packaging space.

In some implementation manners, in addition to the circuit shown in FIG. 1 , the ranging apparatus 100 may further include a scanning module for changing the propagation direction of at least one laser pulse sequence emitted from the transmitting circuit.

Wherein, the module including the transmitting circuit 110, the receiving circuit 120, the sampling circuit 130 and the operation circuit 140, or the module including the transmitting circuit 110, the receiving circuit 120, the sampling circuit 130, the operation circuit 140 and the control circuit 150 may be referred to as the measuring circuit A ranging module, which can be independent of other modules, such as a scanning module.

A coaxial optical path may be used in the ranging device, that is, the light beam emitted by the ranging device and the reflected light beam share at least part of the optical path in the ranging device. For example, after at least one laser pulse sequence emitted by the transmitting circuit changes its propagation direction through the scanning module, the laser pulse sequence reflected by the detection object passes through the scanning module and then enters the receiving circuit. Alternatively, the distance-measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance-measuring device and the reflected light beam are respectively transmitted along different optical paths in the distance-measuring device. FIG. 2 shows a schematic diagram of an embodiment in which the distance measuring device of the present invention adopts a coaxial optical path.

The ranging apparatus 200 includes a ranging module 210, and the ranging module 210 includes a transmitter 203 (which may include the above-mentioned transmitting circuit), a collimating element 204, a detector 205 (which may include the above-mentioned receiving circuit, sampling circuit and arithmetic circuit) and Optical path changing element 206 . The ranging module 210 is used for emitting a light beam, receiving the returning light, and converting the returning light into an electrical signal. Among them, the transmitter 203 can be used to transmit a sequence of optical pulses. In one embodiment, the transmitter 203 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the transmitter 203 is a narrow bandwidth beam with a wavelength outside the visible light range. The collimating element 204 is disposed on the outgoing light path of the transmitter, and is used for collimating the light beam emitted from the transmitter 203, and collimating the light beam emitted by the transmitter 203 into parallel light and outputting to the scanning module. The collimating element also serves to converge at least a portion of the return light reflected by the probe. The collimating element 204 may be a collimating lens or other elements capable of collimating light beams.

In the embodiment shown in FIG. 2, the transmitting optical path and the receiving optical path in the ranging device are combined by the optical path changing element 206 before the collimating element 204, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path more compact. In some other implementations, the emitter 203 and the detector 205 may use respective collimating elements, and the optical path changing element 206 may be arranged on the optical path behind the collimating element.

In the embodiment shown in FIG. 2 , since the beam aperture of the beam emitted by the transmitter 203 is small, and the beam aperture of the return light received by the ranging device is relatively large, the optical path changing element can use a small-area reflective mirror to The transmit light path and the receive light path are combined. In some other implementations, the optical path changing element may also use a reflector with a through hole, wherein the through hole is used to transmit the outgoing light of the emitter 203 , and the reflector is used to reflect the return light to the detector 205 . This can reduce the shielding of the return light by the bracket of the small reflector in the case of using a small reflector.

In the embodiment shown in FIG. 2 , the optical path altering element is offset from the optical axis of the collimating element 204 . In some other implementations, the optical path altering element may also be located on the optical axis of the collimating element 204 .

The ranging device 200 further includes a scanning module 202 . The scanning module 202 is placed on the outgoing optical path of the ranging module 210 . The scanning module 202 is used to change the transmission direction of the collimated beam 219 emitted by the collimating element 204 and project it to the external environment, and project the return light to the collimating element 204 . The returned light is focused on the detector 205 via the collimating element 104 .

In one embodiment, the scanning module 202 can include at least one optical element for changing the propagation path of the light beam, wherein the optical element can change the propagation path of the light beam by reflecting, refracting, diffracting the light beam, or the like. For example, the scanning module 202 includes lenses, mirrors, prisms, gratings, liquid crystals, optical phased arrays (Optical Phased Array) or any combination of the above optical elements. In one example, at least part of the optical elements are moving, for example, the at least part of the optical elements are driven to move by a driving module, and the moving optical elements can reflect, refract or diffract the light beam to different directions at different times. In some embodiments, the multiple optical elements of the scanning module 202 may be rotated or oscillated about a common axis 209, each rotating or oscillating optical element being used to continuously change the propagation direction of the incident beam. In one embodiment, the plurality of optical elements of the scanning module 202 may rotate at different rotational speeds, or vibrate at different speeds. In another embodiment, at least some of the optical elements of scan module 202 may rotate at substantially the same rotational speed. In some embodiments, the plurality of optical elements of the scanning module may also be rotated about different axes. In some embodiments, the plurality of optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which are not limited herein.

In one embodiment, the scanning module 202 includes a first optical element 214 and a driver 216 connected to the first optical element 214, and the driver 216 is used to drive the first optical element 214 to rotate around the rotation axis 209, so that the first optical element 214 changes The direction of the collimated beam 219. The first optical element 214 projects the collimated beam 219 in different directions. In one embodiment, the angle between the direction of the collimated light beam 219 changed by the first optical element and the rotation axis 209 changes with the rotation of the first optical element 214 . In one embodiment, the first optical element 214 includes a pair of opposing non-parallel surfaces through which the collimated beam 219 passes. In one embodiment, the first optical element 214 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the first optical element 214 includes a wedge prism that refracts the collimated light beam 219 .

In one embodiment, the scanning module 202 further includes a second optical element 215 , the second optical element 215 rotates around the rotation axis 209 , and the rotation speed of the second optical element 215 is different from the rotation speed of the first optical element 214 . The second optical element 215 is used to change the direction of the light beam projected by the first optical element 214 . In one embodiment, the second optical element 215 is connected to another driver 217, and the driver 217 drives the second optical element 215 to rotate. The first optical element 214 and the second optical element 215 can be driven by the same or different drivers, so that the rotational speed and/or steering of the first optical element 214 and the second optical element 215 are different, thereby projecting the collimated beam 219 into the external space Different directions can scan a larger spatial range. In one embodiment, the controller 218 controls the drivers 216 and 217 to drive the first optical element 214 and the second optical element 215, respectively. The rotational speeds of the first optical element 214 and the second optical element 215 may be determined according to the area and pattern expected to be scanned in practical applications. Drives 216 and 217 may include motors or other drives.

In one embodiment, the second optical element 215 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 215 comprises a prism whose thickness varies along at least one radial direction. In one embodiment, the second optical element 215 comprises a wedge prism.

In one embodiment, the scanning module 202 further includes a third optical element (not shown) and a driver for driving the movement of the third optical element. Optionally, the third optical element includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element comprises a prism of varying thickness along at least one radial direction. In one embodiment, the third optical element comprises a wedge prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or rotations.

The rotation of each optical element in the scanning module 202 can project light in different directions, such as light 211 and 213 , so as to scan the space around the ranging device 200 . As shown in FIG. 3 , FIG. 3 is a schematic diagram of a scanning pattern of the distance measuring device 200 . It can be understood that when the speed of the optical element in the scanning module changes, the scanning pattern also changes accordingly.

When the light 211 projected by the scanning module 202 hits the detected object 201 , a part of the light is reflected by the detected object 201 to the distance measuring device 200 in a direction opposite to the projected light 211 . The returning light 212 reflected by the probe 201 passes through the scanning module 202 and then enters the collimating element 204 .

A detector 205 is placed on the same side of the collimating element 204 as the emitter 203, and the detector 205 is used to convert at least part of the return light passing through the collimating element 204 into an electrical signal.

In one embodiment, each optical element is coated with an anti-reflection coating. Optionally, the thickness of the anti-reflection film is equal to or close to the wavelength of the light beam emitted by the emitter 203, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is coated on the surface of an element located on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path for transmitting at least the wavelength band of the light beam emitted by the transmitter, Reflects other bands to reduce noise from ambient light to the receiver.

In some embodiments, the transmitter 203 may comprise a laser diode through which laser pulses are emitted on the nanosecond scale. Further, the laser pulse receiving time can be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse to determine the laser pulse receiving time. In this way, the ranging apparatus 200 can calculate the TOF by using the pulse receiving time information and the pulse sending time information, so as to determine the distance from the probe 201 to the ranging apparatus 200 .

The distance and orientation detected by the ranging device 200 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like. In one embodiment, the distance measuring device of the embodiment of the present invention can be applied to a movable platform, and the distance measuring device can be installed on the movable platform body of the movable platform. The movable platform with the distance measuring device can measure the external environment, for example, measure the distance between the movable platform and obstacles for obstacle avoidance and other purposes, and perform two-dimensional or three-dimensional mapping of the external environment. In some embodiments, the movable platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera. When the ranging device is applied to the unmanned aerial vehicle, the movable platform body is the fuselage of the unmanned aerial vehicle. When the distance measuring device is applied to an automobile, the movable platform body is the body of the automobile. The vehicle may be an autonomous driving vehicle or a semi-autonomous driving vehicle, which is not limited herein. When the distance measuring device is applied to the remote control car, the movable platform body is the body of the remote control car. When the distance measuring device is applied to the robot, the movable platform body is the robot. When the ranging device is applied to the camera, the movable platform body is the camera itself.

As shown in Figure 4, the ranging principle of the Time-of-Flight (TOF) method is as follows: the transmitter of the ranging device emits a laser pulse, and at the same time, the receiver enters a receivable state, and after a period of time After the laser pulse is reflected back to the receiving end of the ranging device by the measured object, the reflected signal of the measured object is received, and a return light pulse signal is _formed . Calculate the distance between the measured object and the distance measuring device.

Existing TOF laser ranging technology cannot effectively identify and filter interfering signals. As shown in Figure 5, the T ₀ pulse is the return light pulse signal reflected on the measured object by the laser pulse emitted by the laser ranging device itself, which is defined as an effective return light pulse signal in this application; Then, in the time window in which the receiving end waits to receive the valid return optical pulse signal, there may be interference signals received by the receiving end, namely T _{noise_0} and T _{noise_1} in FIG. 5 , which are defined as interference signals in this application. The interference signals such as The laser pulse signal emitted by other ranging devices, the reflected light signal of the laser pulse emitted by other ranging devices reflected by the object, or the stray light signal formed by the reflection of the laser pulse signal emitted by the ranging device itself inside the ranging device . When the ranging device transmits a single pulse signal, T ₀ , T _{noise_0} and T _{noise_1} have no difference to the receiving end, so the ranging device cannot correctly identify and filter the interference signal, nor can it measure according to the effective return light pulse signal Correct detection distance value.

Based on this, an embodiment of the present invention proposes a laser ranging method, which is used to solve the interference problem existing in the laser ranging technology. FIG. 6 shows a schematic flowchart of a laser ranging method 600 according to an embodiment of the present invention. As shown in FIG. 6, the laser ranging method 600 includes the following steps:

In step S610, at least two laser pulse signals are continuously emitted according to a preset time interval;

In step S620, receiving the back light pulse signal, and determining the receiving time of the back light pulse signal;

In step S630, according to the preset time interval and the receiving time, determine the effective return light pulse signals reflected back by the measured object from the at least two laser pulse signals in the return light pulse signals;

In step S640, the distance between the distance measuring device and the measured object is determined according to the receiving time of the effective return light pulse signal.

The laser ranging method according to the embodiment of the present invention continuously transmits at least two laser pulse signals at a preset time interval in a short period of time in the transmitting stage. The return light pulse signal reflected by the measured object from the at least two emitted laser pulse signals is extracted in time, so as to effectively distinguish the effective return light pulse signal and the interference signal in the return light pulse signal.

In step S610, the number of continuously emitted laser pulse signals may be two or three or more. If the number of continuously emitted laser pulse signals is at least three, the number of consecutively emitted laser pulse signals is The preset time interval between the two laser pulses may be the same or different; the following description will mainly take the continuous emission of two laser pulse signals as an example.

Exemplarily, at least two laser pulse signals may be transmitted by the transmitting circuit of the ranging device. The transmitting circuit includes a laser transmitter such as a laser diode, through which laser pulses of nanosecond level can be transmitted; at least two laser pulse signals can be continuously transmitted through the same transmitting circuit of the ranging device, or can be transmitted through different ranging devices. The transmit circuits are turned on at the same time and transmit separately. The emission directions of the at least two laser pulse signals are the same, and since the at least two laser pulse signals are continuously emitted in a short period of time, they can be irradiated on the same object to be measured.

In some embodiments, the preset time interval between two adjacent laser pulse signals is subject to certain constraints. First, considering that the two laser pulse signals cannot affect each other, the preset time interval between transmitting two adjacent laser pulse signals is not less than the charging and discharging time of the distance measuring device, specifically, not less than the transmitting laser pulse signal The charging and discharging time of the laser is determined to avoid that the laser is still charged at the time point after the emission of a laser pulse signal, thereby affecting the normal emission of the laser pulse signal. For example, if the charging and discharging time is 50ns, the preset time interval is not less than 50ns.

Secondly, considering the sampling frequency and range of the ranging device, the preset time interval should not be too long. Exemplarily, the preset time interval is not greater than the difference between the sampling interval time of the ranging device and the time-of-flight (TOF) corresponding to the range limit of the ranging device, so as to avoid being damaged at the measurement range limit. When measuring objects, only the first echo pulse signal can be received, and the subsequent echo pulse signals cannot be received beyond the sampling interval time. For example, when the sampling frequency of the ranging device is 240kHz and the range is 500m, then the sampling interval is 4.1667us, and the TOF corresponding to the range limit is 3.3333us. If the receiving time of the return light pulse signal of the first laser pulse signal in the two adjacent laser pulse signals is 3.3333us, the receiving time of the return light pulse signal of the second laser pulse signal should be 4.1667us before it can be sampled . Therefore, in order to ensure that the return light pulse signals of the two laser pulse signals can be normally received and sampled, the preset time interval between the two should be less than (4.1667-3.3333=0.8334) us.

In some embodiments, the preset time interval between two adjacent laser pulse signals is fixed. In other embodiments, the preset time interval between two adjacent laser pulse signals can be modulated, and before step S610, it also includes modulating the preset time interval between two adjacent laser pulse signals . Several optional modulation modes of the preset time interval are described below, but it should be noted that the modulation modes of the preset time interval are not limited to the following:

The first modulation method may be called a random number method, that is, the preset time interval ΔT is randomly generated between a preset minimum time interval T _min and a preset maximum time interval T _max . For example, the random number generating function rand( ) can be used to generate ΔT randomly, and the upper and lower limits of the random number generating function are set as T _max and T _min respectively. Wherein, T _max may correspond to the difference between the sampling interval time of the distance measuring device and the TOF corresponding to the range limit, and T _min may correspond to the charging and discharging time of the distance measuring device.

The second modulation method may be called a fixed value method, that is, a fixed value is taken between a preset minimum time interval T _min and a preset maximum time interval T _max as the preset time interval ΔT.

In some embodiments, the size of the fixed value is negatively correlated with the distance between the measured object and the ranging device, that is to say, the farther the distance between the measured object and the ranging device, the closer ΔT is At T _min , the closer the distance between the measured object and the ranging device, the closer ΔT is to T _max . The reason is that part of the interference signal may be the reflected light of the outgoing laser pulse signal reflected in the ranging device itself and incident on the receiving end, and its TOF is short. If the distance between the measured object and the ranging device is short, Then, there may be a phenomenon that the effective return light pulse signal is fused with this part of the emitted light, so the method of increasing the preset time interval is adopted to avoid the difficulty in identifying the effective return light pulse signal due to the occurrence of the fusion phenomenon.

Among them, since the distance between the measured object and the ranging device is accurately calculated in the subsequent steps, when the measured object is located in the region of interest, the distance between the region of interest and the ranging device has a predetermined Therefore, the distance range between the measured object and the distance measuring device can be determined according to the distance between the region of interest and the distance measuring device, and the corresponding preset time interval can be selected according to the distance range.

The third modulation method can be called the random number method with limited value. Wherein, the preset time interval may be randomly selected from the pre-established time interval list or the preset time interval may be selected in sequence, that is, ΔT=[T ₀ , T ₁ , . . . T _n ]. The preset time interval in the time interval list is selected between the minimum time interval T _min and the preset maximum time interval T _max .

In other embodiments, the preset time interval may also be selected between a preset minimum time interval and a preset maximum time interval based on the motion state of the distance measuring device or the motion state of the measured object. Further, the size of the preset time interval is negatively correlated with the motion speed of the distance measuring device or the motion speed of the measured object, or in other words, the size of the preset time interval is related to the relative motion speed between the distance measuring device and the measured object. is a negative correlation, that is, the faster the measured object moves relative to the ranging device, the smaller the preset time interval; the slower the measured object moves relative to the ranging device, the larger the preset time interval. Therefore, when the measured object moves relatively fast relative to the distance measuring device, a smaller preset time interval can be used to avoid the distance between the measured object and the distance measuring device when different laser pulse signals are irradiated to the measured object. The distance difference is too large, so as to prevent the interval between the effective return light pulse signals and the preset time interval from being too large, and improve the success rate of extracting the effective return light pulse signal.

In some embodiments, the modulation mode for modulating the preset time interval may be selected according to the current scene. For example, if the moving speed or distance of the measured object in the current scene has a wide distribution range and great uncertainty, such as a road scene, the random number method or the random number method with limited values can be selected to share the error or limited Random number method for the value. Similarly, if the current scene cannot be determined, the random number method can also be used. Alternatively, if the measured object in the current scene is mainly in a static state, for example, if the current scene is an indoor scene, a fixed value method may be used to modulate the preset time interval. Exemplarily, the mapping relationship between each scene and the corresponding modulation mode may be preset, and when the user selects the current scene or the ranging device itself recognizes the current scene, the modulation mode suitable for the current scene is selected according to the mapping relationship.

In some embodiments, the modulation mode for modulating the preset time interval may be selected according to the distance between the measured object and the distance measuring device. For example, when the distance distribution range is wide, the random number method or the random number method with limited value can be used; when the distance distribution range is narrow, the fixed value method can be used. Alternatively, the modulation method for modulating the preset time interval can be selected according to the motion state of the measured object or the ranging device. For example, when the measured object or the ranging device is in motion, the motion state based on the ranging device can be used Or the motion state of the object to be measured is between the preset minimum time interval and the preset maximum time interval to select the modulation mode of the preset time interval; when the measured object and the distance measuring device are in a static state, a fixed value can be used Law. Besides, the modulation mode for modulating the preset time interval can also be selected according to the user's instruction.

In step S620, a back light pulse signal is received, and the receiving time of the back light pulse signal is determined.

Exemplarily, in the receiving stage, the receiving circuit of the ranging device receives the optical signal through the photosensitive element, and the photosensitive element includes but is not limited to photodiode, avalanche photodiode or charge coupled element, and converts the received optical signal into an electrical signal. After that, the photosensitive element sends the electrical signal to the primary or secondary amplifying circuit for amplification, and sends the amplified electrical signal to the sampling circuit. As an implementation, the sampling circuit includes a comparator (for example, an analog comparator (COMP) for converting an electrical signal into a digital pulse signal) and a time measurement circuit, via a primary or secondary amplifier circuit The amplified electrical signal enters the time measurement circuit after passing through the comparator, and the time measurement circuit conducts counts.

Wherein, the time measurement circuit may be a time-to-data converter (Time-to-Data Converter, TDC). The TDC can be an independent TDC chip, or based on Field-Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC) or Complex Programmable Logic Device , the internal delay chain of programmable devices such as CPLD to realize the TDC circuit of time measurement, or the circuit structure of time measurement by using high frequency clock or the circuit structure of time measurement by counting method.

Exemplarily, the first input terminal of the comparator is used to receive an electrical signal input from the amplifying circuit, and the electrical signal may be a voltage signal or a current signal; the second input terminal of the comparator is used to receive a preset threshold value, which is input to the comparator. The electrical signal of the device is compared with a preset threshold. The output signal of the comparator is connected to the TDC, and the TDC can measure the time information of the output signal edge of the comparator. The measured time is based on the transmission time of the optical pulse signal, that is, the time difference between the transmission and reception of the laser pulse signal can be measured. .

As another implementation manner, the sampling module may also include an analog-to-digital converter (Analog-to-Digital Converter, ADC). After the analog signal input to the sampling module is converted by the ADC, the digital signal can be output to the operation module.

In the receiving stage, what the distance measuring device receives not only includes the effective return light pulse signal reflected by the measured object, but also includes the interference signal of the laser pulse signal transmitted in step S610. Interference signals include but are not limited to laser pulses emitted by other ranging devices, laser pulses emitted by other ranging devices reflected by objects, and laser pulses emitted by the ranging device itself reflected on the inner surface of the ranging device. stray light. The ranging device cannot identify the valid return light pulse signal and the interference signal in the receiving stage. In this stage, the receiving time of each return light pulse signal needs to be determined, so as to be used to determine the return light pulse signal according to the receiving time in the subsequent step S630. Valid return light pulse signal.

Step S630 may be implemented by an arithmetic circuit of the distance measuring device. In step S630, a valid return light pulse signal is identified from the plurality of return light pulse signals by comparing the time interval between every two return light pulse signals with a preset time interval.

As shown in FIG. 7 , taking the continuous emission of two laser pulse signals in step S610 as an example, it is assumed that the ranging device receives four return light pulse signals in step S620, namely T0, T1, T2, T3, among which T0 and T1 The time interval with other return light pulse signals deviates from the preset time interval, so it is an interference signal, and the time interval between T2 and T3 is approximately equal to the preset time interval, which is an effective return light pulse signal.

It should be noted that although the distances between each signal in Figure 7 are relatively close, in fact, the pulse width of the return light pulse signal is nanosecond level, the time window is millisecond level, and the interference signal is randomly distributed in the current time window, the interference The probability that the time interval between signals or the time interval between the interference signal and the valid return light pulse signal is close to or equal to the preset time interval is extremely low. In general, only the time interval between the valid return light pulse signals can be approximately equal to Preset time interval.

In practical applications, due to the existence of measurement errors, the time interval between two valid return light pulse signals is difficult to be strictly equal to the preset time interval, so as long as the time interval between the receiving times of adjacent return light pulse signals is the same as the preset time interval If the deviation between the time intervals is not greater than the preset threshold, it can be regarded as a valid return light pulse signal. Wherein, considering the measurement accuracy of the distance measuring device, the preset threshold is not less than the timing accuracy of the timer used to determine the receiving time of the return light pulse signal, so as to ensure that the distance measuring device can distinguish the two return light pulse signals.

Taking the number of laser pulse signals continuously emitted in step S610 as two as an example, an algorithm flow for identifying valid return light pulse signals is: if the current first return light pulse signal is not the last return light pulse signal, then Calculate the time interval between the first return light pulse signal and each return light pulse signal after the first return light pulse signal in turn; if the time interval between the first return light pulse signal and the subsequent second return light pulse signal is equal to If the deviation between the preset time intervals is not greater than the preset threshold, it is determined that the first return light pulse signal and the second return light pulse signal are valid return light pulse signals; if the first return light pulse signal and the first return light pulse signal are valid return light pulse signals; The deviation between the time interval between the subsequent return light pulse signals and the preset time interval is greater than the preset threshold value, then it is determined that the first return light pulse signal is an interference signal, and the post-processing of the first return light pulse signal is continued. A return light pulse signal is used for the above judgment.

A specific algorithm embodiment is shown in FIG. 8 . Assuming that two laser pulse signals are emitted in step S610, the preset time interval between them is denoted as ΔT, and n return light pulse signals are received in step S620, wherein the TOF of the i-th return light pulse signal is denoted as T _i , i∈[0,n-1], then Fig. 8 shows an exemplary process of identifying valid return light pulse signals among n return light pulse signals:

As shown in FIG. 8 , in step 810 , the TOFs of n return light pulse signals are obtained, and the determination is made from the light flight time T ₀ of the first return light pulse signal.

In step 820, it is determined whether i<n holds. Since i≤n-1, the last return light pulse signal is the i-1th return light pulse signal, so if i≥n, the process is ended; if i<n, step 830 is executed, and it is judged that j=i+1 Whether <n is established, that is, it is judged whether the current i-th return light pulse signal is the last return light pulse signal. If j<n does not hold, that is, the current i-th echoing pulse signal is the last echoing pulse signal, the process ends; if j<n holds, that is, the j-th echoing pulse still exists after the current echoing pulse signal signal, then step 840 can be executed to judge the i-th return-light pulse signal and the j-th return light according to the optical flight time T _i of the i-th return-light pulse signal and the light-of-flight time T _j of the j-th return-light pulse signal Whether the pulse signal is a valid return light pulse signal.

Among them, if the deviation between the time interval between T _j and T _i and the preset time interval ΔT does not exceed the preset threshold, it is determined that the ith return light pulse signal and the jth return light pulse signal are valid return light Pulse signal; if the deviation between the time interval between T _j and T _i and the preset time interval ΔT exceeds the preset threshold, make j=j+1, and judge whether there is T _j+1 , if so, then Continue to judge whether the deviation between the interval between the optical flight time T _i of the i-th returning light pulse signal and the optical flight time T _j +1 of the j+1-th returning light pulse signal and the preset time interval ΔT does not exceed The preset threshold, and so on, until a valid return light pulse signal is found and the process is ended; or, if the interval between the ith return light pulse signal and the light flight time of each subsequent return light pulse signal exceeds ΔT , then it is judged that the i-th return light pulse signal is an interference signal, and it continues to judge whether the i+1th return light pulse signal is a valid return light pulse signal.

The exemplary process of identifying valid return light pulse signals when two laser pulse signals are continuously emitted has been described above with reference to FIG. 8 . Similarly, if the number of continuously emitted laser pulse signals exceeds two, the next round of judgment can be continued on this basis. For example, taking the continuous emission of three laser pulse signals as an example, if the deviation between the time interval between T _j and T _i and the first preset time interval ΔT1 does not exceed the first preset threshold, then continue to judge the difference between Tj and the following Whether the deviation between the time interval between the light flight times of each return light pulse signal and the second preset time interval ΔT2 does not exceed the second preset threshold, and the time interval between T _j and T _i is the same as When the deviation between the first preset time interval ΔT1 does not exceed the first preset threshold, and the deviation between the time interval between _Tk and _Tj and the second preset time interval ΔT2 does not exceed the second preset threshold , judging that the ith, jth and kth return light pulse signals are valid return light pulse signals, and if the jth return light pulse signal does not have the kth return light pulse signal that meets the above requirements, it is determined that the th return light pulse signal The i and jth return light pulse signals are interference signals; thus, possible received interference signals can be further eliminated. The first preset ΔT1 and ΔT2 may be the same or different; and the first preset threshold and the second preset threshold may be the same or different.

In step S640, the distance between the distance measuring device and the measured object is determined according to the receiving time of the effective return light pulse signal.

Wherein, the distance between the distance measuring device and the measured object can be determined according to the interval between the reception time of any valid return light pulse signal and the emission time of the valid return light pulse signal.

Assuming that the starting point of the transmission time is recorded as 0, the arrival time of the received pulse is recorded as t _tof , and c is the speed of light, the distance d between the measured object and the ranging device is:

In some embodiments, the distance between the distance measuring device and the measured object may be determined according to the receiving time of at least two valid return light pulse signals, and the average value of the determined at least two distances may be calculated to obtain As the final measurement result, thus improving the accuracy of the measured distance.

To sum up, the laser ranging method 600 according to the embodiment of the present invention transmits at least two laser pulse signals continuously, and extracts an effective return light pulse signal in the return light pulse signal according to the receiving time of the return light pulse signal, thereby effectively identifying and filtering The interference signal improves the robustness and anti-interference ability of the ranging device.

The ranging method according to the embodiment of the present invention has been exemplarily described above. The distance measuring apparatus 100 provided according to the embodiment of the present invention is described below with reference to FIG. 1 again. The ranging apparatus 100 according to the embodiment of the present invention may be used to implement the above-described ranging method 600 according to the embodiment of the present invention. For the sake of brevity, only the main structure and function of the distance measuring device 100 are described below, and some specific details that have been described above are omitted.

As shown in FIG. 1 , the ranging apparatus 100 includes a transmitting circuit 110 , a receiving circuit 120 , a sampling circuit 130 and an arithmetic circuit 140 . The transmitting circuit 110 is used to continuously transmit at least two laser pulse signals according to a preset time interval, the receiving circuit 120 is used to receive the return light pulse signal, the sampling circuit 130 is used to determine the receiving time of the return light pulse signal, and the arithmetic circuit 140 is used for determining, according to the receiving time, in the return light pulse signal, the effective return light pulse signal reflected by the object to be measured, and the receiving time of the valid return light pulse signal according to the at least two laser pulse signals Determine the distance between the distance measuring device and the measured object. Optionally, the distance measuring device 100 may further include a control circuit (not shown), which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit. For other specific structures of the distance measuring apparatus 100, reference may be made to the relevant descriptions of the distance measuring apparatuses in FIG. 1 and FIG. 2 above.

In some embodiments, the ranging apparatus 100 further includes a control circuit 150, and the control circuit 150 is configured to modulate the preset time interval. Exemplarily, the modulation modes used to modulate the preset time interval include the following:

As a first modulation manner, the preset time interval may be randomly generated between a preset minimum time interval and a preset maximum time interval.

As a second modulation manner, a fixed value may be taken between a preset minimum time interval and a preset maximum time interval as the preset time interval. Exemplarily, the size of the fixed value is negatively correlated with the distance between the measured object and the distance measuring device. Exemplarily, the measured object is located within a region of interest.

As a third modulation manner, the preset time intervals may be randomly selected from a pre-established time interval list or the preset time intervals may be selected in sequence.

In addition, the preset time can also be selected between a preset minimum time interval and a preset maximum time interval based on the motion state of the distance measuring device and/or the motion state of the measured object interval. Exemplarily, the size of the preset time interval is negatively correlated with the movement speed of the distance measuring device and/or the movement speed of the measured object.

As described above, the modulation modes include multiple types, and the control circuit 150 is further configured to select a modulation mode for modulating the time interval. Exemplarily, the modulation mode selection mode includes at least one of the following: selecting the modulation mode according to the current scene, selecting the modulation mode according to the distance between the measured object and the ranging device, selecting the modulation mode according to the The modulation mode is selected by the motion state of the object to be measured and/or the motion state of the distance measuring device, or the modulation mode is selected according to a user instruction.

Exemplarily, the deviation between the time interval between the receiving times of adjacent valid return light pulse signals and the preset time interval is not greater than the preset threshold.

Exemplarily, the preset threshold value is not less than the timing precision of the timer used to determine the receiving time of the return light pulse signal.

Exemplarily, the preset time interval is not less than the charging and discharging time of the distance measuring device that emits the laser pulse signal.

Exemplarily, the preset time interval is not greater than the difference between the sampling interval time of the ranging device and the time of flight of light corresponding to the range limit of the ranging device.

In one embodiment, according to the receiving time, the effective return light pulse signals of the at least two laser pulse signals reflected back by the measured object are determined in the return light pulse signal, including:

If the current first return light pulse signal is not the last return light pulse signal, then sequentially calculate the time interval between the first return light pulse signal and each return light pulse signal after the first return light pulse signal;

If the deviation between the time interval between the first return light pulse signal and the second return light pulse signal after the first return light pulse signal and the preset time interval is not greater than the preset threshold, the first return light pulse signal is determined and the second return light pulse signal is an effective return light pulse signal;

If the deviation between the time interval between the first returning light pulse signal and each returning light pulse signal after the first returning light pulse signal and the preset time interval is greater than the preset threshold, the first returning light pulse signal is determined to be interfere with the signal.

In some embodiments, the number of laser pulse signals transmitted by the transmitting circuit 110 is at least three, and the preset time interval between every two adjacent laser pulse signals is the same or different.

The ranging device of the embodiment of the present invention continuously transmits at least two laser pulse signals, and extracts the effective return light pulse signal in the return light pulse signal according to the receiving time of the return light pulse signal, so as to effectively identify and filter the interference signal, and improve the Robustness and anti-jamming capability of ranging devices.

An embodiment of the present invention further provides a movable platform, the movable platform includes any of the above distance measuring devices and a movable platform body, and the distance measuring device is mounted on the movable platform body. In some embodiments, the movable platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, a camera, and a gimbal. When the movable platform is an unmanned aerial vehicle, the body of the movable platform is the fuselage of the unmanned aerial vehicle. When the movable platform is an automobile, the movable platform body is the body of the automobile. The vehicle may be an autonomous vehicle or a semi-autonomous vehicle, which is not limited herein. When the movable platform is a remote control car, the movable platform body is the body of the remote control car. When the movable platform is a robot, the movable platform body is a robot. When the movable platform is a camera, the movable platform body is the camera itself. When the movable platform is a gimbal, the movable platform body is a gimbal body. The gimbal can be a handheld gimbal, or a gimbal mounted on a car or an aircraft.

Since the movable platform adopts the distance measuring device according to the embodiment of the present invention, it also has the advantages mentioned above.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server, or data center by wire (eg, coaxial cable, optical fiber, digital subscriber line, DSL) or wireless (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disk, hard disk, magnetic tape), optical media (eg, digital video disc (DVD)), or semiconductor media (eg, solid state disk (SSD)), etc. .

Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above-described example embodiments are exemplary only, and are not intended to limit the scope of the invention thereto. Various changes and modifications can be made therein by those of ordinary skill in the art without departing from the scope and spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as claimed in the appended claims.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or May be integrated into another device, or some features may be omitted, or not implemented.

In the description provided herein, numerous specific details are set forth. It will be understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it is to be understood that in the description of the exemplary embodiments of the invention, various features of the invention are sometimes grouped together , or in its description. However, this method of the invention should not be interpreted as reflecting the intention that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the corresponding claims reflect, the invention lies in the fact that the corresponding technical problem may be solved with less than all features of a single disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

It will be understood by those skilled in the art that all features disclosed in this specification (including the accompanying claims, abstract and drawings) and any method or apparatus so disclosed may be used in any combination, except that the features are mutually exclusive. Processes or units are combined. Each feature disclosed in this specification (including accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that although some of the embodiments described herein include certain features, but not others, included in other embodiments, that combinations of features of different embodiments are intended to be within the scope of the invention within and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

Various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some modules according to embodiments of the present invention. The present invention may also be implemented as apparatus programs (eg, computer programs and computer program products) for performing part or all of the methods described herein. Such a program implementing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such signals may be downloaded from Internet sites, or provided on carrier signals, or in any other form.

It should be noted that the above-described embodiments illustrate rather than limit the invention, and that alternative embodiments may be devised by those skilled in the art without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. do not denote any order. These words can be interpreted as names.

Claims (35)

1. A laser ranging method, characterized in that the method comprises:

   Continuously emit at least two laser pulse signals at preset time intervals;

   Receive the return light pulse signal, and determine the receiving time of the return light pulse signal;

   According to the preset time interval and the receiving time, in the return light pulse signal, determine the effective return light pulse signal of the at least two laser pulse signals reflected by the measured object;

   The distance between the distance measuring device and the measured object is determined according to the receiving time of the effective return light pulse signal.
2. The method of claim 1, further comprising: modulating the preset time interval.
3. The method according to claim 2, wherein the modulation mode adopted for modulating the preset time interval comprises:

   The preset time interval is randomly generated between a preset minimum time interval and a preset maximum time interval.
4. The method according to claim 2, wherein the modulation mode adopted for modulating the preset time interval comprises:

   A fixed value is taken between a preset minimum time interval and a preset maximum time interval as the preset time interval.
5. The method of claim 4, wherein the size of the fixed value is negatively correlated with the distance between the measured object and the distance measuring device.
6. The method of claim 5, wherein the measured object is located in a region of interest.
7. The method according to claim 2, wherein the modulation mode used for modulating the preset time interval comprises:

   The preset time intervals are randomly selected from a pre-established time interval list or the preset time intervals are selected sequentially.
8. The method according to claim 2, wherein the modulation mode used for modulating the preset time interval comprises:

   The preset time interval is selected between a preset minimum time interval and a preset maximum time interval based on the motion state of the distance measuring device and/or the motion state of the measured object.
9. The method according to claim 8, wherein the size of the preset time interval is negatively correlated with the movement speed of the distance measuring device and/or the movement speed of the measured object.
10. The method according to any one of claims 2-9, characterized in that, the modulation modes used for performing the modulation include a plurality of modulation modes, and the method further comprises:

    Select the modulation method that modulates the time interval.
11. The method of claim 10, wherein the selection of the modulation mode includes at least one of the following:

    The modulation method is selected according to the current scene, the modulation method is selected according to the distance between the measured object and the ranging device, and the selection is based on the motion state of the measured object and/or the motion state of the ranging device the modulation mode, or the modulation mode is selected according to a user instruction.
12. The method according to claim 1, wherein the deviation between the time interval between the receiving times of the adjacent valid return light pulse signals and the preset time interval is not greater than a preset threshold.
13. The method of claim 12, wherein the preset threshold is not less than the timing precision of a timer used to determine the receiving time of the return light pulse signal.
14. The method according to any one of claims 1-13, wherein the preset time interval is not less than the charging and discharging time of the ranging device that emits the laser pulse signal.
15. The method according to any one of claims 1-14, wherein the preset time interval is not greater than the light flight corresponding to the sampling interval time of the ranging device and the range limit of the ranging device difference between times.
16. The method according to any one of claims 1-15, wherein the at least two laser pulse signals are determined in the return light pulse signal according to the preset time interval and the receiving time The effective return light pulse signal reflected by the measured object, including:

    If the current first return light pulse signal is not the last return light pulse signal, then sequentially calculate the time interval between the first return light pulse signal and each return light pulse signal after the first return light pulse signal;

    If the deviation between the time interval between the first return light pulse signal and the second return light pulse signal after the first return light pulse signal and the preset time interval is not greater than a preset threshold, determine The first return light pulse signal and the second return light pulse signal are the effective return light pulse signal;

    If the deviation between the time interval between the first return light pulse signal and each return light pulse signal after the first return light pulse signal and the preset time interval is greater than the preset threshold, then It is determined that the first return optical pulse signal is an interference signal.
17. The method according to any one of claims 1-16, wherein the number of the laser pulse signals is at least three, and the preset time between every two adjacent laser pulse signals The interval is the same or different.
18. A distance measuring device, characterized in that the distance measuring device comprises:

    a transmitting circuit for continuously transmitting at least two laser pulse signals according to a preset time interval;

    The receiving circuit is used to receive the optical pulse signal;

    a sampling circuit for determining the receiving time of the return light pulse signal;

    an arithmetic circuit, configured to determine, in the return light pulse signal, the effective return light pulse signal reflected by the object to be measured from the at least two laser pulse signals according to the preset time interval and the receiving time, and according to the returned light pulse signal The receiving time of the effective return light pulse signal determines the distance between the distance measuring device and the measured object.
19. The distance measuring device according to claim 18, characterized in that, the distance measuring device further comprises a control circuit, and the control circuit is configured to modulate the preset time interval.
20. The distance measuring device according to claim 19, wherein the modulation mode used for modulating the preset time interval comprises:

    The preset time interval is randomly generated between a preset minimum time interval and a preset maximum time interval.
21. The distance measuring device according to claim 19, wherein the modulation mode used for modulating the preset time interval comprises:

    A fixed value is taken between a preset minimum time interval and a preset maximum time interval as the preset time interval.
22. The distance measuring device according to claim 21, wherein the size of the fixed value is negatively correlated with the distance between the measured object and the distance measuring device.
23. The distance measuring device according to claim 22, wherein the measured object is located in a region of interest.
24. The distance measuring device according to claim 19, wherein the modulation method used for modulating the preset time interval comprises:

    The preset time intervals are randomly selected from a pre-established time interval list or the preset time intervals are selected sequentially.
25. The distance measuring device according to claim 19, wherein the modulation method used for modulating the preset time interval comprises:

    The preset time interval is selected between a preset minimum time interval and a preset maximum time interval based on the motion state of the distance measuring device and/or the motion state of the measured object.
26. The distance measuring device according to claim 25, wherein the size of the preset time interval is negatively correlated with the movement speed of the distance measurement device and/or the movement speed of the measured object.
27. The distance measuring device according to any one of claims 21-26, characterized in that, the modulation modes include multiple types, and the control circuit is further configured to:

    Select the modulation method that modulates the time interval.
28. The distance measuring device according to claim 27, wherein the selection mode of the modulation mode includes at least one of the following:

    The modulation method is selected according to the current scene, the modulation method is selected according to the distance between the measured object and the ranging device, and the selection is based on the motion state of the measured object and/or the motion state of the ranging device the modulation mode, or the modulation mode is selected according to a user instruction.
29. The distance measuring device according to claim 18, wherein the deviation between the time interval between the receiving times of the adjacent valid return light pulse signals and the preset time interval is not greater than a preset threshold.
30. The distance measuring device according to claim 29, wherein the preset threshold is not less than the timing accuracy of a timer used to determine the receiving time of the return light pulse signal.
31. The distance measuring device according to any one of claims 18 to 30, wherein the preset time interval is not less than the charging and discharging time of the distance measuring device that emits the laser pulse signal.
32. The distance-measuring device according to any one of claims 18-31, wherein the preset time interval is not greater than the sampling interval time of the distance-measuring device and the range limit of the distance-measuring device corresponding to Difference between light times of flight.
33. The distance measuring device according to any one of claims 18-32, wherein the at least two lasers are determined in the return light pulse signal according to the preset time interval and the receiving time The effective return light pulse signal reflected by the measured object, including:

    If the current first return light pulse signal is not the last return light pulse signal, then calculate the time interval between the first return light pulse signal and each return light pulse signal after the first return light pulse signal in turn;

    If the deviation between the time interval between the first return light pulse signal and the second return light pulse signal after the first return light pulse signal and the preset time interval is not greater than a preset threshold, determine The first return light pulse signal and the second return light pulse signal are the effective return light pulse signal;

    If the deviation between the time interval between the first return light pulse signal and each return light pulse signal after the first return light pulse signal and the preset time interval is greater than the preset threshold, then It is determined that the first return optical pulse signal is an interference signal.
34. The distance measuring device according to any one of claims 18 to 33, wherein the number of the laser pulse signals is at least three, and the preset distance between every two adjacent laser pulse signals is at least three. Set the time interval to be the same or different.
35. A movable platform, characterized in that the movable platform comprises:

    Movable platform body;

    The distance measuring device according to any one of claims 18-34, which is mounted on the movable platform body.

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