KR102608534B1 - LiDAR ANTI-INTERFERENCE DEVICE USING MULTI-PULSE - Google Patents

Abstract

The present invention provides a pulse laser that generates a single pulse; A beam splitter that splits a single pulse generated by the pulse laser into a plurality of pulses; A signal delay unit that delays the pulses so that the plurality of pulses divided by the beam splitter reach the transmitter with time differences; And a transmitter that integrates a plurality of pulses arriving at different times and transmits them as a multi-pulse, giving the number of pulses included in the transmitted multi-pulse, the size of the pulse, or the time difference between pulses as a unique identification value for LiDAR. This prevents interference between LiDARs.

Description

LiDAR anti-interference device using multi-pulse {LiDAR ANTI-INTERFERENCE DEVICE USING MULTI-PULSE}

The present invention relates to a LiDAR interference prevention device, and in particular, to a LiDAR interference prevention device using multipulses that prevents interference between LiDARs by encrypting pulses transmitted by LiDAR.

LiDAR (Light Detection and Ranging) is a technology that measures distance using a laser. It has been developed to build terrain data to build 3D information and visualize it, and is being applied to fields such as construction and national defense.

In particular, as self-driving car technology develops, the use of LiDAR for high-accuracy object recognition is increasing. This is to compensate for the shortcomings of the camera sensor used previously and to ensure stable object recognition. Through the use of LiDAR, the distance to an object can be measured, and through this, autonomous driving technology with high stability can be developed.

Recently, as the number of autonomous vehicles using LiDAR increases, interference between LiDARs has become a problem. There are two types of interference between LiDARs: direct interference and indirect interference. When there are two different LiDARs A and B, direct interference occurs when B directly receives the pulse transmitted by A, and interference occurs when B receives the pulse transmitted by A reflected from an object. This is indirect interference. When this interference phenomenon occurs, phenomena such as recognizing an object that does not exist or recognizing the distance to the object as being closer occur. As the number of vehicles equipped with LiDAR increases, it can cause major problems.

Therefore, there is a need for a device that can prevent interference between LiDARs by generating various multi-pulses with only a single pulse to identify specific LiDARs.

delete

The purpose of the present invention is to provide a LiDAR interference prevention device using multipulses that prevents interference between LiDARs by generating unique multipulses that can distinguish LiDARs as a single pulse.

In order to achieve the above object, the present invention includes a pulse laser that generates a single pulse; A beam splitter that splits a single pulse generated by the pulse laser into a plurality of pulses; A signal delay unit that delays the pulses so that the plurality of pulses divided by the beam splitter reach the transmitter with time differences; And a transmitter that integrates a plurality of pulses arriving at different times and transmits them as a multi-pulse, giving the number of pulses included in the transmitted multi-pulse, the size of the pulse, or the time difference between pulses as a unique identification value for LiDAR. This prevents interference between LiDARs.

Preferably, the signal delay unit can generate a time difference between pulses by adjusting the length of the optical fiber through which the plurality of pulses divided by the beam splitter pass.

Preferably, it may further include a receiving unit that receives the multi-pulse reflected waves transmitted from the transmitting unit.

Preferably, it may further include a signal recording unit that stores the multi-pulses transmitted from the transmitter.

Preferably, it may further include an identification unit that determines whether the reflected wave received by the receiver matches the multi-pulse stored in the signal recording unit.

According to the present invention, there is an advantage that multiple pulses can be generated using only a single pulse by dividing a single pulse with a beam splitter and controlling the time difference between the divided pulses by the signal delay unit.

In addition, the present invention has the advantage of preventing interference between LiDARs by generating a unique multi-pulse that can distinguish between LiDARs as a single pulse using the generated multi-pulses.

Figure 1 shows a configuration diagram of a LiDAR interference prevention device according to an embodiment of the present invention.
Figure 2 shows the multipulse generation process of the LiDAR interference prevention device according to an embodiment of the present invention.
Figure 3 shows multipulses identified by the time difference between pulses according to an embodiment of the present invention.
Figure 4 shows a multipulse identified by the number of pulses according to an embodiment of the present invention.
Figure 5 shows a multipulse identified by the number of pulses and the time difference between pulses according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited or limited by the exemplary embodiments. The same reference numerals in each drawing indicate members that perform substantially the same function.

The purpose and effect of the present invention can be naturally understood or become clearer through the following description, and the purpose and effect of the present invention are not limited to the following description. Additionally, in describing the present invention, if it is determined that a detailed description of known techniques related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

Figure 1 shows a configuration diagram of a LiDAR interference prevention device 1 according to an embodiment of the present invention. Referring to FIG. 1, the LiDAR interference prevention device 1 includes a pulse laser 100, a beam splitter 200, a signal delay unit 300, a transmitter 400, a receiver 500, a signal recorder 600, and It may include an identification unit 700.

The LiDAR interference prevention device 1 can prevent interference between LiDARs by assigning the number of pulses included in the transmitted multipulses, the size of the pulses, or the time difference between pulses as a unique identification value of the LiDAR. The LiDAR interference prevention device (1) can be applied to all devices equipped with LiDAR, such as autonomous vehicles, mobile robots, and drones.

The LiDAR interference prevention device (1) can generate multipulses using only a single pulse. The LiDAR interference prevention device (1) can generate numerous multi-pulses with one pulse by adding or adjusting the length of the delay path. The LiDAR interference prevention device 1 can prevent interference between LiDARs by using multipulses to assign unique pulse values to each LiDAR.

The LiDAR interference prevention device (1) can be replaced with a beam splitter (200) and a signal delay unit (300) containing a simple optical fiber instead of a pulse programming element to generate multipulses, thereby reducing costs and making it easier to manufacture. . The LiDAR interference prevention device (1) has a structure that changes a single pulse into a multipulse, unlike existing devices that require a single pulse to be generated several times to generate a multipulse, so it can perform high-speed scanning without lowering the pulse repetition rate.

The pulse laser 100 can generate a single pulse. A single pulse generated by the pulse laser 100 is split in the beam splitter 200. The pulse laser 100 may be used in existing LiDAR without any particular restrictions.

The beam splitter 200 can split a single pulse generated by the pulse laser 100 into a plurality of pulses. The beam splitter 200 can split a single pulse at a certain ratio. In one embodiment, when splitting a single pulse at a ratio of 5:5, the beam splitter 200 can split a single pulse with a size of 100 into two single pulses with a size of 50 and the same width. In another embodiment, when splitting a single pulse at a ratio of 2.5:2.5:2.5:2.5, the beam splitter 200 divides a single pulse with a size of 100 into four single pulses with a size of 25 and the same width. You can. The pulse divided by the beam splitter 200 may be delayed in the signal delay unit 300, resulting in a time difference.

Figure 2 shows the multipulse generation process of the LiDAR interference prevention device 1 according to an embodiment of the present invention. Referring to FIG. 2, the signal delay unit 300 may delay pulses so that the plurality of pulses divided by the beam splitter 200 reach the transmitter 400 with time differences. The signal delay unit 300 can cause the plurality of pulses divided by the beam splitter 200 to move through different paths, thereby generating a time difference. In one embodiment, the signal delay unit 300 may pass one of the pulses divided into two by the beam splitter 200 through a general path and the other through a delay path. The signal delay unit 300 can delay the time of the pulse passed through the delay path so that it reaches the transmitter 400 later than the pulse passed through the normal path.

이고 길이가

인 일반경로로 통과시킬 수 있다. 신호지연부(300)는 다른 하나의 펄스는 광섬유의 굴절률이

이고 길이가

인 지연경로로 통과시킬 수 있다. The signal delay unit 300 can generate a time difference between pulses by adjusting the length of the optical fiber through which the plurality of pulses divided by the beam splitter 200 pass. To explain the principle of generating a time difference between pulses based on FIG. 2, the signal delay unit 300 determines that one of the divided pulses has a refractive index of the optical fiber.

and the length is

It can be passed through the normal route. The signal delay unit 300 is configured so that the other pulse has a refractive index of the optical fiber.

and the length is

It can be passed through a delay path.

이고 빛의 속도가

일 때,

(시간차)와

(거리차)의 관계는 다음과 같은 식을 만족한다. The refractive index of the optical fiber used in the signal delay unit 300 is

And the speed of light is

when,

(time difference) and

The relationship between (distance difference) satisfies the following equation.

[Equation 1]

이 증가할수록

도 증가하게 됨을 알 수 있다. 신호지연부(300)는 이러한 원리에 의해 지연경로의 수량 및 길이에 따라 복수의 펄스의 시간차를 발생시킬 수 있다. 신호지연부(300)에서 생성된 복수의 펄스는 시간차를 두고 송신부(400)에 도달되어 하나의 멀티펄스로 구성될 수 있다. Referring to [Equation 1],

As this increases

It can be seen that it also increases. Based on this principle, the signal delay unit 300 can generate time differences between a plurality of pulses according to the quantity and length of delay paths. A plurality of pulses generated in the signal delay unit 300 may arrive at the transmitter 400 with time differences and constitute one multi-pulse.

The transmitter 400 can integrate a plurality of pulses that arrive with time differences into one and transmit it as a multi-pulse. The transmitter 400 does not transmit a plurality of pulses that arrive at a time difference in the signal delay unit 300 separately, but integrates them into one multi-pulse and transmits them. The multipulse transmitted from the transmitter 400 is a unique multipulse transmitted from the corresponding LiDAR and can be unique identification information that distinguishes the LiDAR.

The receiving unit 500 may receive a multi-pulse reflected wave transmitted from the transmitting unit 400. The receiver 500 may receive a reflected wave from the multi-pulse transmitted from the transmitter 400 reflected on the surface of the target object in order to calculate the distance to the target object in LiDAR. The identification unit 700 may determine whether the reflected wave received by the receiving unit 500 matches the multipulse transmitted by the transmitting unit 400.

The signal recording unit 600 can store multipulses transmitted from the transmitting unit 400. The multipulses stored in the signal recording unit 600 can be LiDAR's unique identification information. The signal recording unit 600 may provide a reference multipulse for comparing whether the reflected wave received by the receiving unit 500 is a multipulse transmitted from the transmitting unit 400.

The identification unit 700 may determine whether the reflected wave received by the receiver 500 matches the multi-pulse stored in the signal recording unit 600. The identification unit 700 may determine whether it is a multi-pulse with unique identification information to prevent interference with other LiDARs. The identification unit 700 may determine whether the received reflected wave matches the multipulse stored in the signal recording unit 600 by comparing the size, time difference, or number of the plurality of pulses constituting the multipulse.

Figure 3 shows multipulses identified by the time difference between pulses according to an embodiment of the present invention. Referring to FIG. 3, the signal delay unit 300 causes two pulses split at a 5:5 ratio in the beam splitter 200 to arrive at the transmitter 400 with a time difference, thereby forming multi-pulses divided by the time difference. It can be done.

의 시간차가 발생한 2개의 펄스로 구성된 멀티펄스를 나타낸다. 도 3의 (b)는 단일 펄스가 빔스플리터(200)에서 분할되고, 신호지연부(300)에서

의 시간차가 발생한 2개의 펄스로 구성된 멀티펄스를 나타낸다. 도 3의 (a)와 (b)에 나타난 각각의 멀티펄스의 펄스간 시간차는

와

로 다르므로 구분될 수 있다. 즉, 송신부(400)에서 송신한 멀티펄스의 반사파를 수신할 때, 식별부(700)는 송신한 멀티펄스를 기록하여 반사파가 송신부(400)에서 송신한 것인지 식별이 가능하다. 따라서, 이를 통해 LiDAR 간섭 방지 장치(1)는 직접간섭과 간접간섭의 구분없이 다른 LiDAR에서 전송된 수많은 멀티펄스와 송신부(400)에서 전송한 멀티펄스를 구분하여 간섭을 방지할 수 있다. In (a) of Figure 3, a single pulse is split in the beam splitter 200 and in the signal delay unit 300.

It represents a multi-pulse consisting of two pulses with a time difference of . In (b) of Figure 3, a single pulse is split in the beam splitter 200 and in the signal delay unit 300.

It represents a multi-pulse consisting of two pulses with a time difference of . The time difference between pulses of each multipulse shown in Figures 3 (a) and (b) is

and

Because they are different, they can be distinguished. That is, when receiving a multi-pulse reflected wave transmitted from the transmitter 400, the identification unit 700 records the transmitted multi-pulse and can identify whether the reflected wave was transmitted from the transmitter 400. Therefore, through this, the LiDAR interference prevention device 1 can prevent interference by distinguishing between numerous multipulses transmitted from other LiDARs and multipulses transmitted from the transmitter 400 without distinguishing between direct interference and indirect interference.

Figure 4 shows a multipulse identified by the number of pulses according to an embodiment of the present invention. Referring to FIG. 4, the beam splitter 200 can be divided at different ratios to vary the number of pulses to form multi-pulses distinguished by the number or size of pulses.

의 시간차가 발생한 2개의 펄스로 구성된 멀티펄스를 나타낸다. 도 4의 (b)는 단일 펄스가 빔스플리터(200)에서 2.5:2.5:2.5:2.5의 비율로 분할되고, 신호지연부(300)에서 펄스간

의 시간차가 발생한 4개의 펄스로 구성된 멀티펄스를 나타낸다. 도 4의 (a)와 (b)에 나타난 각각의 멀티펄스의 시간차는

으로 동일하다. 그러나, 도 4의 (a)의 각 펄스의 크기는 50, 펄스의 개수는 2개이고, 도 4의 (b)의 각 펄스의 크기는 25, 펄스의 개수는 4개이므로 두 멀티펄스는 구분될 수 있다. In (a) of Figure 4, a single pulse is split at a ratio of 5:5 in the beam splitter 200, and in the signal delay unit 300

It represents a multi-pulse consisting of two pulses with a time difference of . In (b) of Figure 4, a single pulse is split at a ratio of 2.5:2.5:2.5:2.5 in the beam splitter 200, and the pulse-to-pulse signal is divided in the signal delay unit 300.

It represents a multi-pulse consisting of 4 pulses with a time difference of . The time difference between each multipulse shown in Figures 4 (a) and (b) is

is the same as However, the size of each pulse in (a) of Figure 4 is 50 and the number of pulses is 2, and the size of each pulse in (b) of Figure 4 is 25 and the number of pulses is 4, so the two multi-pulses cannot be distinguished. You can.

Figure 5 shows a multipulse identified by the number of pulses and the time difference between pulses according to an embodiment of the present invention. Referring to FIG. 5, the beam splitter 200 can configure multi-pulses divided by the number or size of pulses, and the signal delay unit 300 can configure multi-pulses divided by time difference.

의 시간차가 발생한 2개의 펄스로 구성된 멀티펄스를 나타낸다. 도 5의 (b)는 단일 펄스가 빔스플리터(200)에서 2.5:2.5:2.5:2.5의 비율로 분할되고, 신호지연부(300)에서 각 펄스간

,

,

의 시간차가 발생한 4개의 펄스로 구성된 멀티펄스를 나타낸다. 도 5의 (a)와 (b)에 나타난 각각의 멀티펄스의 펄스간 시간차, 펄스의 크기, 및 펄스의 개수가 모두 다르므로 두 멀티펄스는 구분될 수 있다. In (a) of Figure 5, a single pulse is split at a ratio of 5:5 in the beam splitter 200, and in the signal delay unit 300

It represents a multi-pulse consisting of two pulses with a time difference of . In (b) of Figure 5, a single pulse is split at a ratio of 2.5:2.5:2.5:2.5 in the beam splitter 200, and the signal delay unit 300 divides each pulse into

,

,

It represents a multi-pulse consisting of 4 pulses with a time difference of . Since the inter-pulse time difference, pulse size, and number of pulses of each multi-pulse shown in (a) and (b) of Figures 5 are all different, the two multi-pulses can be distinguished.

As seen through FIGS. 3, 4, and 5, the LiDAR interference prevention device 1 generates multipulses with unique identification information by varying the size, number, or time difference between pulses to prevent interference between LiDARs. It can be prevented.

Although the present invention has been described in detail through representative embodiments above, those skilled in the art will understand that various modifications can be made to the above-described embodiments without departing from the scope of the present invention. will be. Therefore, the scope of rights of the present invention should not be limited to the described embodiments, but should be determined not only by the claims described later, but also by all changes or modified forms derived from the claims and the concept of equivalents.

1: LiDAR anti-interference device
100: pulse laser
200: Beam splitter
300: signal delay unit
400: Transmitting unit
500: Receiving unit
600: signal recorder
700: identification unit

Claims (5)

Pulse laser that generates a single pulse;
Beam spool that divides a single pulse generated by the pulse laser into multiple pulses
liter;
A plurality of pulses divided by the beam splitter are transmitted to the following transmitter with a time difference.
A signal delay unit that delays the pulse to arrive; and
Multiple pulses that arrive at different times are integrated into one and transmitted as a multi-pulse.
includes a transmitting unit,
The signal delay unit adjusts the length of the optical fiber through which the plurality of pulses divided by the beam splitter pass to generate a time difference between pulses that satisfies Equation 1.

(Δt; time difference, n: refractive index, ΔL: distance difference, c; speed of light)

A LiDAR interference prevention device characterized in that it prevents interference between LiDARs by assigning the number of pulses included in the transmitted multipulse, the size of the pulses, or the time difference between pulses as a unique identification value of the LiDAR.

delete According to claim 1,
LiDAR interference prevention device further comprising a receiving unit that receives multi-pulse reflected waves transmitted from the transmitting unit.
In clause 3 ,
Further comprising a signal recording unit that stores the multipulses transmitted from the transmitter.
LiDAR interference prevention device featuring.
In clause 4 ,
The reflected wave received from the receiving unit and the multipulse stored in the signal recording unit are
A LiDAR interference prevention device further comprising an identification unit that determines whether the device is approaching.