Lidar system and method for sensing surroundings

Abstract

The application relates to a lidar system (10) for a vehicle (20), the lidar system (10) comprising: an optical transmitting device (12) designed to emit an optical signal (L), an optical receiving device (14) designed to receive the optical signal (L), an optical deflecting device (16) comprising at least two mirror surfaces (16.1, 16.2, 16.3, 16.4) arranged at an angle to one another, a further deflecting element (30), the deflecting device (16) being designed to deflect, by means of a first of the at least two mirror surfaces (16.1, 16.2, 16.3, 16.4), the optical signal (L) on a first partial path (P1) from the transmitting device (12) to a sensing region (22) and to deflect, by means of a second of the at least two mirror surfaces (16.1, 16.2, 16.3, 16.4), on a second partial path (P2), the optical signal (L) reflected in the sensing region (22) to the further deflecting element (30), the further deflecting element (30) being designed to deflect the optical signal on a third partial path (P3) from the second mirror surface (16.1, 16.2, 16.3, 16.4) to the receiving device (14). The application further relates to a vehicle (20) comprising a lidar system (10), and to a method for sensing surroundings.

Description

[0001] LIDAR SYSTEM AND ENVIRONMENTAL SENSING METHOD

[0002] Technical field

[0003] The application relates to a lidar system for a vehicle and to a vehicle that incorporates such a lidar system. The application further relates to a method for environmental sensing using an optical signal from a lidar system.

[0004] background

[0005] Modern vehicles (cars, vans, trucks, motorcycles, etc.) are equipped with a multitude of sensor systems whose data serves to inform the driver and / or provide data to driver assistance systems. These sensor systems detect the vehicle's surroundings, including other road users. Based on the collected data, a model of the vehicle's environment can be created, and the system can react to changes in this environment.

[0006] Sensor systems are constantly being developed for various functions, such as environmental sensing in the near and far range of vehicles, including passenger cars and commercial vehicles. Sensor systems can also be used for driver assistance systems, particularly those for autonomous or semi-autonomous vehicle control. They can be used specifically for detecting obstacles and / or other road users in the front, rear, or blind spot areas of a vehicle. Sensor systems can be based on various sensor principles, such as radar, ultrasound, optics, etc.

[0007] An important optical sensor principle for environmental perception, e.g., of vehicles, is lidar technology (Lidar stands for Light Detection and Ranging). A lidar system comprises an optical transmitter and an optical receiver. The transmitter can emit an optical signal in the form of light, which can be continuous or pulsed. The transmitted optical signal can also be modulated. In particular, optical signals in the form of laser beams in the ultraviolet, visible, or infrared range can be used in a lidar system. The receiver can detect the optical signal after it is reflected from a point in the vicinity of the lidar system. The received optical signal can then be analyzed using the transmitted optical signal, for example, using a time-of-flight method, to determine the spatial location and distance of the point from which the reflection occurred.In this context, reflection or reflected light is understood to mean any light that is thrown back and is intended in particular to include light thrown back by scattering or absorption-emission.

[0008] The reflected optical signal can be detected in the receiving device via a receiving sensor. Receiving sensors in lidar systems can have multiple receiving elements, called pixels, for opto-electrical conversion. The pixels can be configured to receive optical signals from different viewing angles.

[0009] Scanning lidar systems emit optical signals that move in a scanning direction. This scanning motion can be achieved by deflecting the optical signal transmitted by the optical transmitter using a deflection device. The deflection of the light can be effected, for example, by rotating the deflection device, which may include at least one rotating mirror.

[0010] US10324170B1 describes a lidar system comprising a light source, a scanner, and a first and second receiver. The light source is configured to generate a first and a second beam of light. The scanner is configured to scan the lidar system's field of view using the first and second beams. The first receiver is configured to receive scattered light from the first beam. The second receiver is configured to receive scattered light from the second beam. The scanner includes a rotatable polygon mirror and other rotatable or fixed mirrors.

[0011] US20220342045A1 describes a lidar system in which an optical signal travels along an optical path in both transmit and receive directions. A rotatable polygon mirror and another mirror are arranged in the common optical path for both transmit and receive directions.

[0012] US11768294 describes a lidar system in which a reflective surface of a polygonal mirror and another mirror are arranged in an optical path in both the transmit and receive directions. An optical receiver can include optics, such as lenses, for receiving, redirecting, focusing, amplifying, and / or filtering.

[0013] German patent DE102022122223A1 describes a lidar system in which a deflection device with mirror surfaces is arranged between the transmitting device and the receiving device. The deflection of the optical signal transmitted by the optical transmitting device towards the detection area is effected by a first mirror surface, and the deflection of the optical signal reflected from the detection area towards the receiving device is effected by a second mirror surface.

[0014] Overview

[0015] A lidar system for a vehicle comprises an optical transmitter, an optical receiver, an optical deflector, and a further deflection element. The optical transmitter is configured to transmit an optical signal. The optical receiver is configured to receive the optical signal. The optical deflector comprises at least two mirror surfaces arranged at an angle to each other. The deflector is configured to deflect the optical signal along a first path from the transmitter to a detection area by means of a first of the at least two mirror surfaces, and to deflect the optical signal reflected in the detection area along a second path by means of a second of the at least two mirror surfaces to the further deflection element. The further deflection element is configured to deflect the optical signal along a third path from the second mirror surface to the receiver.

[0016] The lidar system is designed for environmental sensing of the vehicle. It is configured to monitor the detection area using an optical signal. The detection area of ​​the lidar system is the area monitored by the lidar system, within which, for example, objects can be detected. The detection area is located in the vicinity of the lidar system.

[0017] The optical signal is emitted by the transmitting device, travels along an optical path to the respective detection area, is reflected there, and received by the receiving device. The optical path has a first optical sub-path, which runs from the transmitting device to the detection area. The optical path further has a second optical sub-path, which runs from the detection area to the additional deflection element. The optical path further has a third optical sub-path, which runs from the second mirror surface of the deflection device to the receiving device. The second and third sub-paths overlap in the area between the second mirror surface and the additional deflection element.

[0018] The deflection device is a spatial arrangement of at least two mirror surfaces. These mirror surfaces can be held by a base body. The deflection device can therefore consist of a base body with mirror surfaces arranged on it. The mirror surfaces have the property of reflecting and deflecting optical rays. This effect can be achieved, in particular, by coating the surfaces of a suitably shaped base body with an optically reflective material.

[0019] The first mirror surface of the deflection device deflects the optical signal along the first optical path to the detection area. The second mirror surface of the deflection device deflects the optical signal along the second optical path to the further deflection element. The mirror surfaces of the deflection device can be planar. The further deflection element deflects the optical signal along the third optical path to the receiving device. Here, the term "planar mirror surface" is used in such a way that the normals through the points on the mirror surface are parallel to each other.

[0020] The deflection at the respective mirror surface of the deflection device, as well as the deflection at the further mirror surface, can in particular include the reflection at the respective mirror surface.

[0021] The described lidar system can be built compactly. This compact design is made possible, firstly, by positioning the transmitting and receiving units on opposite sides of the deflection element, and secondly, by further "folding" the optical path on the receiver side through the additional deflection element. This allows the receiving unit, which may include space-consuming receiving optics, to be positioned on a different axis.

[0022] The compact design of the lidar system described above is advantageous for several possible installation locations within the vehicle, such as the front or rear. It is particularly beneficial for installation in the upper part of the windshield. One advantage of this placement is that the lidar system's field of view can be cleaned simultaneously with the windshield cleaning. This eliminates the need for a separate cleaning process, such as removing ice and / or dirt, for a lidar system mounted elsewhere. Compared to a lidar system mounted externally on the vehicle's body, for example, on the roof, the interior placement behind the windshield offers the advantage of reduced wind resistance.

[0023] In one embodiment of the lidar system, the deflection device is rotatable about a rotational axis. The detection area can be scanned by the optical signal through the rotational movement of the deflection device.

[0024] Here, the rotational movement of the deflection device is controlled and regulated, for example by a processing unit of the lidar system, so that the detection area is scanned—that is, sampled step by step—by the optical signal deflected by the deflection device. By evaluating the optical signal, for example in the processing unit, objects within the detection area can be detected. By appropriately selecting properties of the light, such as the frequency or the type of modulation, scanning of a near and / or far range can be enabled.

[0025] The rotary motion can be implemented as a pivoting or a rotational motion. A pivoting motion is a rotation whose deflection is limited to an angle less than 360° and does not encompass a complete revolution around the axis of rotation. This allows, for example, in an embodiment with two mirror surfaces on the deflection device, the space allocated for the pivoting motion of the deflection device to be limited to the pivoting motion itself. This enables an even more compact design of the lidar system. The rotational motion allows for energy conservation during the rotation of the deflection device. Therefore, the rotational motion can be implemented in a particularly energy-efficient manner.

[0026] In one embodiment of the lidar system, the at least two mirror surfaces are parallel to the axis of rotation of the deflection device. This enables uniform scanning of the detection area. Optionally, the deflection device can have more than two mirror surfaces, with all mirror surfaces of the deflection device being parallel to the axis of rotation.

[0027] In one embodiment of the lidar system, the axis of rotation runs along, and in particular perpendicular to, the first, second, and / or third partial path. This enables precise scanning of the detection area while maintaining a compact lidar system design.

[0028] In one embodiment of the lidar system, the transmitter and receiver are arranged on opposite sides of the deflection device. In this lidar system, the optical signal is deflected along its optical path by different mirror surfaces of the deflection device. This allows the transmitter and receiver to be positioned on opposite sides of the deflection device, which can be advantageous in terms of installation space. It increases flexibility in positioning the transmitter and receiver, thereby making the dimensions and extent of the lidar system more compact in one or more desired directions. For example, the height required by the lidar system can be reduced, which can be particularly advantageous for installation in the upper area of ​​the vehicle's windshield.

[0029] In one embodiment of the lidar system, the base body of the deflection device essentially has the shape of a prism, with a mirror surface arranged on each of the prism's lateral surfaces. The base and top surfaces of the prism are polygonal in shape. Optionally, more than two or all of the prism's lateral surfaces can have mirror surfaces. Optionally, the axis of rotation can penetrate the base and top surfaces within the prism.

[0030] In one embodiment of the lidar system, the deflection device has the form of a right prism. The base body of the deflection device thus has the shape of a prism. The axis of rotation runs parallel to the mirror surfaces and can penetrate the base and top surfaces of the prism within the prism, particularly in the center.

[0031] In one embodiment of the lidar system, the deflection device has four mirror surfaces and a square as its base and top surface. The axis of rotation can, in particular, pass through the center of the base and top surfaces. In one embodiment of the lidar system, the direction of the optical signal on the first path segment before deflection at the first mirror surface corresponds to the direction of the optical signal on the second path segment after deflection at the second mirror surface. This segment of the second path segment after deflection at the second mirror surface also lies on a portion of the third path segment. Such a lidar system can be built compactly because the transmitting and receiving devices can be arranged on opposite sides of the deflection device.

[0032] In one embodiment of the lidar system, the receiver comprises a receiving sensor and a tube, with the third path segment running lengthwise along the tube after deflection at the further deflection element. This third path segment can thus run in a different direction than the first path segment before deflection at the first mirror surface and the second path segment after deflection at the second mirror surface. This allows for a more compact lidar system design. This is particularly advantageous on the receiver side, as the receiver tube can now be rotated, for example, 90% in its direction of extension, and the dimensions of the lidar system are correspondingly reduced in this direction. The receiver tube can have an elongated shape that is longer in the longitudinal direction relative to the optical path than in the transverse direction.The additional deflection element allows the extension direction of the tube to be shifted in such a way that the lidar system as a whole is more compact and / or its dimensions are designed in such a way that the available installation space in the vehicle is optimally utilized.

[0033] In one embodiment of the lidar system, receiving lenses of the receiver are arranged within the tube. Due to the described design of the lidar system, the tube can be positioned flexibly enough that, despite the spatial dimensions of the cube, the lidar system does not become too wide.

[0034] In one embodiment of the lidar system, the additional deflection element has a further mirror surface for deflecting the optical signal. This additional deflection element can have a further mirror surface for deflection. The additional mirror surface can be flat. The additional mirror surface can be of the same type as the mirror surfaces of the deflection device. Alternatively or additionally, the additional deflection element can have MEMS mirrors for deflecting the optical signal. Other deflection possibilities by the additional deflection element include phased optical arrays or, for example, liquid crystal-based systems.

[0035] In one embodiment of the lidar system, a further optical element, in particular a further lens, is arranged in the third sub-path. It can be arranged in the third sub-path before or after the further deflection element, e.g. to compensate for its optical losses.

[0036] In one embodiment of the lidar system, the additional optical element is arranged in the third path segment between the second mirror surface and the additional deflection element. This position is particularly advantageous for compensating for intensity losses that can be caused, for example, by the additional deflection element.

[0037] In one embodiment of the lidar system, the additional optical element, in particular the additional lens, is arranged in the second partial path, and the additional optical element can be arranged, in particular, between the second mirror surface and the additional deflection element. The additional optical element can serve to compensate for intensity losses.

[0038] A vehicle is equipped with the described lidar system. The monitoring area of ​​the lidar system, which is integrated into the vehicle, is located in the vehicle's vicinity and can be used, for example, to monitor a near or far area in the front, rear, or blind spot of the vehicle. A far area can be configured, for example, to monitor a far field at distances of, in particular, between approximately 10 m and approximately 300 m. A near area can be configured, for example, to monitor a near field at distances of up to approximately 10 m. Ultra-far fields of up to 1000 m are also conceivable. The lidar system can thus be used in conjunction with the vehicle to monitor the roadway for objects and for autonomous or semi-autonomous driving functions within the vehicle.

[0039] A lidar system for an environmental sensing method comprises an optical deflection device having at least two mirror surfaces arranged at an angle to each other. The environmental sensing method using an optical signal from the lidar system comprises:

[0040] • Emitting the optical signal, • Deflecting the optical signal into a detection area by means of a first of at least two mirror surfaces,

[0041] • Deflection of the optical signal reflected in the detection area to a further deflection element by means of a second of the at least two mirror surfaces,

[0042] • Deflection of the optical signal by means of the additional deflection element,

[0043] • Receiving the optical signal.

[0044] Transmission can be performed by the transmitting device. Receipt can be performed by the receiving device. The control of the transmission process by the transmitting device, and the control of the reception process by the receiving device, can be carried out in a processing unit of the lidar system.

[0045] The process can include an evaluation of the transmitted and received optical signal. This evaluation can, for example, include a time-of-flight measurement of the optical signal and object detection. The evaluation can be performed, for example, in the processing unit of the lidar system. The evaluation can then take into account which mirror surface and position of the deflection device deflected the optical signal.

[0046] The process can be implemented using the described lidar system, which can be designed to be compact and can be used as a lidar system with an installation location in the upper windshield area.

[0047] In one embodiment of the method, the optical signal is manipulated, in particular focused, by means of a further optical element, in particular a further lens, after deflection by the second mirror surface and before deflection by the further deflection element. This allows any optical losses to be compensated for.

[0048] Tour list

[0049] The following section provides further explanation and description of exemplary implementations of this application with reference to the figures. They show

[0050] Fig. 1 shows a schematic representation of a vehicle with a lidar system and detection range,

[0051] Fig. 2 shows a schematic representation of a first embodiment of the lidar system, Fig. 3 shows a schematic representation of a second embodiment of the lidar system.

[0052] The same reference symbols are used in the figures for identical or similar elements. Representations in the figures may not be to scale.

[0053] Tour description

[0054] Figure 1 schematically shows a vehicle 20, for example a passenger car. The vehicle 20 has a lidar system 10. The lidar system 10 is arranged in a front area of ​​the vehicle 20, and a detection area 22 is located in front of the vehicle 20 in the direction of travel. The lidar system 10 can, in particular, be arranged in the upper area of ​​a windshield inside the vehicle 20.

[0055] The lidar system 10 comprises an optical transmitter 12, an optical receiver 14, an optical deflector 16, a further deflector 30, and a computing unit 18. The computing unit 18 can include a processor, an FPGA, or similar for processing data, as well as memory and data input and output interfaces.

[0056] The optical transmitter 12 emits an optical signal L. It has a light source for emitting, for example, laser light. The optical signal L is transmitted along an optical path to the detection area 22. The optical receiver 14 receives the optical signal L reflected at a reflection point in the detection area 22 along the optical path. The reflection can occur, for example, at an object O located in the detection area 22.

[0057] Optionally, the optical transmitter 12 can transmit the optical signal L in pulses. The pulsed optical signal L has short periods during which the optical signal L is transmitted. This can be referred to as a pulse. Between the pulses, the optical transmitter 12 does not transmit any optical signal L.

[0058] The optical deflection device 16 is configured such that it deflects the optical signal L transmitted by the optical transmitter 12 into the detection area 22 on a first sub-path PI of the optical path, and deflects the optical signal L reflected from the detection area 22 to the further deflection element 30 on a second sub-path P2 of the optical path. The deflection device 16 can be controlled by the processing unit 18 such that it can assume several different angular positions and the optical signal L can traverse the detection area 22 accordingly. The optical signal L can be deflected successively at the deflection device 16 in different angular positions such that the optical signal L performs a scanning movement 24 over the detection area 22.

[0059] The deflection device 16 can, for example, comprise a polygon mirror with multiple mirror surfaces that performs a rotational movement to deflect the optical signal L such that the scanning movement 24 is carried out by the optical signal L. During the rotational movement, the angular position of the deflection device 16 is changed. The optical signal L can be emitted in pulsed light pulses. Through the scanning movement 26, information about reflection points with different solid angles relative to the lidar system 10 can be obtained.

[0060] The optical receiving device 14 comprises an optoelectronic receiving sensor 26, also called a detector. The receiving sensor 26 can, for example, have point-shaped sensors, so-called pixels or receiving pixels, which can be arranged in rows or areas. A pixel can, for example, have one or more avalanche photodiodes (APDs) or one or more single-photon avalanche diodes (SPADs). The optoelectronic detector can receive light, in particular the optical signal L, and convert it into electrical receiving signals. The electrical receiving signals can be processed by the processing unit 18.

[0061] The processing unit 18 is configured to control the transmission of the optical signal L depending on the deflection device 16, e.g., depending on the angular position of the deflection device 16. The processing unit 18 is further configured to evaluate the transmitted and received optical signal L. From the evaluation of the optical signal L, environmental information about the surroundings of the vehicle 20 within the detection range 22 can be obtained.

[0062] A point cloud can be generated from the environmental information produced by the lidar system 10 during the evaluation process. Information about each point in the point cloud is provided, depending on the environmental information. In particular, the points in the point cloud contain information about the spatial location and distance of the reflection points within the detection area 22. The reflection points are those points within the detection area 22 where the reflection of the optical signal L emitted and received by the lidar system 10 occurred.

[0063] The point cloud can be used, for example, to detect objects 0 within the detection area 22, to determine the distance to such objects 0, and / or to perform further analyses. The point cloud can be generated, for example, in the lidar system 10 from environmental information, and / or the point cloud can be generated, for example, in another control unit of the vehicle 20 from the environmental information of the lidar system 10.

[0064] The additional control unit can, for example, be configured as the central vehicle computer of vehicle 20, in which data from several sensor systems of vehicle 20 can be received, evaluated, and / or further processed. The additional control unit can, for example, be used to implement autonomous or semi-autonomous driving functions.

[0065] The lidar system 10 can, for example, be mounted or integrated at the front of the vehicle 20. Lidar systems 10 are also possible for other parts of the vehicle 20, e.g., for surround-view functions, such as on the sides and / or rear of the vehicle 20. It is also possible to arrange lidar systems 10 and / or other sensor systems such as radar, ultrasound, etc., on the vehicle 20, particularly in corner areas of the vehicle 20.

[0066] The lidar system 10 can be used to detect stationary or moving objects O in the environment 22. Such objects O can include things such as vehicles, people, animals, plants, obstacles, road surface irregularities, especially potholes or stones, road boundaries, traffic signs, open areas, especially parking lots, precipitation, or the like.

[0067] Figure 2 schematically depicts a first embodiment of the lidar system 10. The deflection device 16 is designed as a polygonal mirror in the form of a prism with a square as its base and top surfaces. The four lateral surfaces of the prism each have a mirror surface 16.1, 16.2, 16.3, 16.4. The deflection device 16 is rotatably mounted about an axis of rotation A and can perform a rotational movement about the axis of rotation A. The transmitter 12 emits the optical signal L by means of a light source. The optical signal L travels along the first sub-path PI of the optical path from the transmitter 12 to the detection area 22. On the first sub-path PI of the optical path, the optical signal L is deflected by a first mirror surface 16.1 of the deflection device 16 in the direction of the detection area 22.

[0068] After reflection in the detection area 22, the optical signal L travels along the second sub-path P2 of the optical path from the reflection point in the detection area 22 to the further deflection element 30. On the second sub-path P2 of the optical path, the optical signal L is deflected at a second mirror surface 16.2 of the deflection device 16 in the direction of the further deflection element 30.

[0069] From the second mirror surface 16.2 to the further deflection element 30, the optical signal L traverses a third sub-path P3 of the optical path. The part of the optical path that runs between the second mirror surface 16.2 and the further deflection element 30 is part of both the second sub-path P2 and the third sub-path P3.

[0070] On the third path segment P3, the optical signal L is deflected towards the receiver 14 by means of the further deflection element 30. Part of the third path segment P3 behind the further deflection element 30 runs inside the tube 32 of the receiver 14. Receiving optics, such as lenses, can be arranged in the tube 32, by means of which the optical signal L is manipulated for reception by the receiver sensor 26. The optical signal L is received by means of the receiver sensor 26.

[0071] By rotating around the axis of rotation A, the optical signal L can be deflected at different angles by the various mirror surfaces 16.1, 16.2, 16.3, 16.4, depending on the angular position of the deflecting element 16, thereby achieving a scanning motion in the detection area 22. The rotation, as well as the transmission and reception processes, can be controlled by the processing unit 18. The rotation, transmission, and reception processes can thus be coordinated.

[0072] As shown in Figure 2, the described embodiment allows the transmitter 12 and the receiver 14 to be arranged on different sides of the lidar system 10. At the same time, the additional deflection element 30 allows the longitudinal extension of the tube 32 of the receiver 14 to be oriented transversely to the direction of the first part of the first path PI and to the direction of the second part of the second path P2. This allows for an advantageous dimensioning of the lidar system 10, which is well suited for the installation space above the windshield of the vehicle 20. Figure 3 shows a second embodiment of the lidar system 10. Compared to the first embodiment shown in Figure 2, this embodiment has an additional lens 34. The additional lens 34 is arranged in the part of the second path P2 that overlaps with the third path 3.The additional lens 34 is therefore arranged in the optical path between the second mirror surface 16.2 and the additional deflecting element 30.

[0073] The optical signal L can be further manipulated, in particular focused, by means of the additional lens 34. This allows, for example, any damping effects caused by the additional deflecting element 30 to be compensated for or reduced.

[0074] Reference sign

[0075] 10 Lidar systems

[0076] 12 optical transmitting device

[0077] 14 optical receiving device

[0078] 16 optical deflection devices

[0079] 16.1-16.4 Mirror surface

[0080] 18 computing units

[0081] 20 vehicles

[0082] 22 Detection area

[0083] 24 Sampling direction

[0084] 26 Receiving sensor

[0085] 28 Direction of rotation

[0086] 30 additional deflection elements

[0087] 32 Tube

[0088] 34 more lenses

[0089] A axis of rotation

[0090] L optical signal

[0091] 0 objects

[0092] Pl, P2, P3 Sub-path

Claims

REQUIREMENTS 1. Lidar system (10) for a vehicle (20), wherein the lidar system (10) comprises: an optical transmitter (12) configured to transmit an optical signal (L), an optical receiver (14) configured to receive the optical signal (L), an optical deflection device (16) comprising at least two mutually angularly arranged mirror surfaces (16.1, 16.2, 16.3, 16.4), a further deflection element (30), wherein the deflection device (16) is configured to deflect the optical signal (L) on a first partial path (PI) from the transmitter (12) to a detection area (22) by means of a first of the at least two mirror surfaces (16.1, 16.2, 16.3, 16.4) and to reflect the optical signal (L) on a first partial path (PI) from the transmitter (12) to a detection area (22) by means of a second of the at least two mirror surfaces (16.1, 16.2, 16.3, 16.4).4) to deflect the optical signal (L) reflected in the detection area (22) on a second partial path (P2) to the further deflection element (30), wherein the further deflection element (30) is configured to deflect the optical signal on a third partial path (P3) from the second mirror surface (16.1, 16.2, 16.3, 16.4) to the receiving device (14).

2. Lidar system (10) according to claim 1, wherein the deflection device (16) is rotatable about a rotation axis (A) and wherein the detection area (22) can be scanned by the optical signal (L) through the rotational movement of the deflection device (16).

3. Lidar system (10) according to claim 2, wherein the at least two mirror surfaces (16.1, 16.2, 16.3, 16.4) run parallel to the axis of rotation (A) of the deflection device (16).

4. Lidar system (10) according to claim 2 or 3, wherein the axis of rotation (A) runs longitudinally, in particular perpendicularly, to the first, second and / or third partial path (PI, P2, P3).

5. Lidar system (10) according to one of the preceding claims, wherein the transmitting device (12) and the receiving device (14) are arranged on different sides of the deflection device (16).

6. Lidar system according to one of the preceding claims, wherein the deflection device (16) essentially has the form of a prism, wherein a respective mirror surface (16.1, 16.2, 16.3, 16.4) is arranged on a respective lateral surface of the prism.

7. Lidar system (10) according to claim 6, wherein the deflection device (16) has the form of a straight prism.

8. Lidar system (10) according to claim 6 or 7, wherein the deflection device (16) has four mirror surfaces (16.1, 16.2, 16.3, 16.4) and a square as the base and top surface.

9. Lidar system according to one of the preceding claims, wherein the direction of the optical signal (L) on the first partial path (PI) before deflection at the first mirror surface (16.1, 16.2, 16.3, 16.4) corresponds to the direction of the optical signal (L) on the second partial path (P2) after deflection at the second mirror surface (16.1, 16.2, 16.3, 16.4).

10. Lidar system (10) according to one of the preceding claims, wherein the receiving device (14) has a receiving sensor (26) and a tube (32), wherein the third partial path (P3) after deflection at the further deflection element (30) runs in a direction longitudinal to the tube (32).

11. Lidar system (10) according to claim 10, wherein receiving lenses of the receiving device (14) are arranged in the tube (32).

12. Lidar system (10) according to one of the preceding claims, wherein the further deflection element (30) has a further mirror surface for deflecting the optical signal (L).

13. Lidar system (10) according to one of the preceding claims, wherein a further optical element, in particular a further lens (34), is arranged in the third partial path (P2).

14. Lidar system (10) according to claim 13, wherein the further optical element is arranged between the second mirror surface (16.1, 16.2, 16.3, 16.4) and the further deflection element (30).

15. Vehicle (20) comprising a lidar system (10) according to any of the preceding claims.

16. Method for environmental detection using an optical signal (L) of a lidar system (10), wherein the lidar system (10) comprises an optical deflection device (16) which has at least two mirror surfaces (16.1, 16.2, 16.3, 16.4) arranged at an angle to each other, wherein the method comprises: Emitting the optical signal (L), Deflection of the optical signal (L) into a detection area (22) by means of a first of the at least two mirror surfaces (16.1, 16.2, 16.3, 16.4), Deflecting the optical signal (L) reflected in the detection area (22) to a further deflection element (30) by means of a second of the at least two mirror surfaces (16.1, 16.2, 16.3, 16.4), Deflection of the optical signal (L) by means of the further deflection element (30), Receiving the optical signal (L).

17. The method of claim 16, further comprising: Manipulating, in particular focusing, the optical signal (L) by means of a further optical element, in particular a further lens (34), after deflection by the second mirror surface (16.1, 16.2, 16.3, 16.4) and before deflection by the further deflection element (30).

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