LiDAR measuring system

Abstract

LIDAR measurement system (10) comprising a LIDAR transmitter unit (14) and a LIDAR receiver unit (12) configured in a focal plane array arrangement, wherein - The LIDAR receiving unit (12) has several sensor elements (26) and wherein - The LIDAR transmitting unit (14) has several emitter elements (22), wherein - several sensor elements (26) form a macrocell (1,2,3,4), wherein the macrocell (1,2,3,4) is assigned to a single emitter element (22), characterized in that the distance (D) between two adjacent emitter elements (22) is not equal to an integer multiple of the distance (d) between two adjacent sensor elements (26), wherein the columns of emitter elements (22) of the LIDAR transmitting unit (14) and the columns of sensor elements (26) of the LIDAR receiving unit (12) have an angle α to each other and wherein the angle α is between 0° and 45°.

Description

[0001] The invention relates to a LIDAR measuring system with a LIDAR receiving unit.

[0002] A LIDAR measurement system is known from WO 2017 081 294. This LIDAR measurement system comprises, among other components, a transmitter unit, a transmitter optics, a receiver optics, and a receiver unit. One or more emitter elements of the transmitter unit emit laser light, which is scattered in various spatial directions by the transmitter optics. The laser light is then reflected by an object and guided to the receiver unit via the receiver optics. The incoming reflected laser light is detected by sensor elements. The advantage of this system is that it can be constructed compactly and is static, thus requiring no movable adjustment elements for the emitter elements and the sensor elements.

[0003] US 2010 / 0051836 A1 discloses an apparatus for creating a depth image. A first beam emitting unit emits a first emission beam, a second beam emitting unit emits a second emission beam, a receiving unit receives a first reflection beam associated with the first emission beam and a second reflection beam associated with the second emission beam, and a processing unit calculates a depth value corresponding to a first pixel based on an electrical charge provided by the first pixel to the receiving unit.

[0004] EP 3 168 641 A1 discloses a method for optical distance measurement using a transmission matrix for transmitting measuring pulses and a reception matrix, wherein only subsets of the transmission elements of the transmission matrix are activated.

[0005] WO 2011 / 029 645 A1 discloses a measuring device for optically measuring a distance to a target object. The measuring device comprises a transmitting device for emitting an optical measuring beam onto the target object, a detecting device with a detection surface for detecting an optical beam reflected by the target object, and an evaluation device.

[0006] WO 2013 / 032954 A1 discloses VCSEL arrays with array and subarray configurations, using diffusion to increase alignment tolerance. Intensity modulation can be achieved by operating groups of VCSEL emitters at maximum bias voltage.

[0007] JP S64-6 716 A discloses a measuring device comprising a matrix with two-dimensionally distributed light spots, a matrix shutter and a device which checks a luminous flux of a measuring surface in order to detect a displacement of the measuring surface.

[0008] The task is to further develop such a LIDAR measuring system, in particular its LIDAR receiving unit, so that incoming laser light can be detected as optimally as possible.

[0009] This object is achieved by a LIDAR measuring system according to patent claim 1. The following dependent patent claims form advantageous embodiments.

[0010] The basic design of the LIDAR measuring system is based on the state of the art. The LIDAR measuring system comprises a LIDAR transmitter unit and a LIDAR receiver unit. Furthermore, the LIDAR measuring system and its components are preferably designed for static, i.e., immobile installation on a motor vehicle. This means that the LIDAR measuring system and its components do not have any active movement or adjustment mechanisms, such as electric motors, for the measuring process.

[0011] The LIDAR receiving unit and / or the LIDAR transmitting unit are advantageously configured in a focal plane array configuration. The elements of the respective unit are arranged essentially in one plane, advantageously on a chip. The respective unit is preferably arranged on the LIDAR measuring system at a focal point of a corresponding optical system, transmitting optics, or receiving optics. In particular, the sensor elements or emitter elements are arranged at the focal point of the receiving optics. Such an optical system can be implemented, for example, by an optical lens system.

[0012] The LIDAR receiver unit has several sensor elements, preferably designed as single-photon avalanche diodes (SPADs). The LIDAR transmitter unit has several emitter elements for emitting laser light, preferably laser pulses. The emitter elements are preferably designed as vertical cavity surface emitting lasers (VCSELs).

[0013] The LIDAR receiver unit and the LIDAR transmitter unit are advantageously arranged next to each other on the LIDAR measurement system. "Next to each other" implies the adjacent arrangement of the LIDAR receiver unit and the LIDAR transmitter unit, i.e., one above the other or diagonally adjacent. The sensor elements and the emitter elements are advantageously arranged on a common plane. Their respective chips are therefore advantageously arranged so that the sensor elements and the emitter elements are on the same plane. A parallel arrangement with a corresponding offset in the normal direction is also possible.

[0014] The LIDAR transmitter unit has a multitude of emitter elements, whose emitted laser light is projected into different solid angles via a transmitter optics. This means that each emitter element is assigned a specific solid angle. The arrangement of the sensor elements of the LIDAR receiver unit and its receiver optics is comparable, so that the receiver optics maps a specific solid angle onto a specific surface of the LIDAR receiver unit.

[0015] In other words, laser light emitted by an emitter element is projected onto an object in the far field via the emitter optics and always onto the same area on the LIDAR receiver unit via the receiver optics. In this area, where laser light is expected, several sensor elements are preferably arranged, which together form a macrocell. The emitter element and such a macrocell are assigned to each other.

[0016] Since a VCSEL is usually larger than a SPAD and thus its laser light can illuminate a plurality of sensor elements, it is also advantageous to configure a large number of sensor elements in macrocells. Such a macrocell can, for example, be defined by the area onto which the emitter element can theoretically or practically image after reflection from an object. This area will be referred to as the imaging area, whereby the area actually illuminated by the laser light, which is smaller than the imaging area, is called the light area. The incoming laser light can be deflected due to various effects, such as optical aberrations in the transmitting and receiving optics, misalignment, or even a front screen. The laser area thus images onto an area within the imaging area. The imaging area is usually many times larger than the light area.

[0017] The sensor elements thus advantageously cover at least the imaging surface, with only a portion of the sensor elements actually being illuminated by laser light during operation. The sensor elements can preferably be activated or deactivated individually or in groups. Non-illuminated sensor elements are advantageously deactivated to reduce detection of ambient radiation.

[0018] The LIDAR measurement system usually also includes electronics for evaluating the detected laser light. However, this electronics will not be described further here. For example, multiple sensor elements, in particular all sensor elements of a macrocell, can be read by a readout element of the evaluation electronics, thus providing a hardware definition of a macrocell. For example, one readout element is provided for a row of macrocells.

[0019] Optics or optical lens systems have the effect that incoming light experiences essentially the same imaging, including any possible aberrations, in neighboring areas. This means that the incoming laser light within the imaging area experiences essentially the same deflection between neighboring macrocells and a static aberration. The deflection of the laser light between neighboring macrocells is thus correlated.

[0020] Therefore, a configuration for the sensor elements is proposed that always enables uniform illumination of the sensor elements of neighboring macrocells, regardless of any imaging errors on average. The sensor elements and the emitter elements have a decorrelated arrangement.

[0021] As an example, consider a configuration consisting of four emitter elements and sixteen corresponding rows of sensor elements, where the spacing between the emitter elements is a multiple of the spacing between the rows of sensor elements. Because the number of rows of sensor elements is an integer multiple of the number of rows of emitter elements, each emitter element images the same location within the imaging area of ​​the macrocell. Therefore, the sensor elements of all four macrocells are identical, meaning they are either optimally or poorly illuminated.

[0022] The distance between two adjacent emitter elements is not equal to an integer multiple of the distance between two adjacent sensor elements. This creates a decorrelated LIDAR measurement system. This ensures that if one emitter element images into a poor area of ​​the macrocell, the neighboring emitter elements in their macrocells image into other, more advantageous areas. This means that while individual macrocells are poorly illuminated, the neighboring ones are significantly better illuminated, so that good illumination is achieved on average. This ensures good detection by the LIDAR measurement system. Such a relationship can be implemented in one or more dimensions, for example, in the column direction or in both column and row directions.

[0023] Neighboring sensor elements are also spaced apart from one another, which varies depending on the arrangement or decorrelated arrangement between emitter elements and sensor elements. The spacing between adjacent sensor elements can vary in the column direction and the row direction. Advantageously, the spacing between adjacent sensor elements is the same in all directions. In another preferred embodiment, the spacing between adjacent sensor elements is smaller in the row direction than in the column direction. The row direction advantageously points from the LIDAR transmitting unit to the LIDAR receiving unit.

[0024] In an advantageous embodiment, it is proposed that the emitter elements and the macrocells are each arranged in a row-column arrangement and wherein the sensor elements are also arranged in a type of row-column arrangement.

[0025] This essentially corresponds to the previously explained division of macrocells and emitter elements, which illuminate or observe a corresponding solid angle via the respective optics. In other words, the arrangement of the macrocells and emitter elements in their respective units is identical to each other. Arranging the sensor elements in the same or a similar type of row-column arrangement is particularly advantageous. The possible types of row-column arrangements are explained in more detail below.

[0026] Advantageously, the distance between two adjacent emitter elements, in particular adjacent rows, is not equal to an integer multiple of the distance between two adjacent rows of sensor elements.

[0027] Furthermore, a LIDAR measurement system according to claim 3 is proposed, which also solves the problem stated above. The dependent claims define advantageous embodiments.

[0028] The previous statements regarding patent claims 1 and 2 are identically applicable to this LIDAR measuring system.

[0029] Here, the combined number of rows of sensor elements of several adjacent macrocells is not equal to the integer multiple of the corresponding emitter elements. This means that at least two emitter elements and their corresponding macrocells are considered. The macrocells have several sensor elements arranged in several rows. Advantageously, the sensor elements are arranged in columns in addition to rows, with two, three, four, or more sensor elements arranged per row.

[0030] The number of all rows of these macroelements is not equal to an integer multiple of the rows of macroelements. Such an arrangement can avoid a corresponding identical repetition, i.e., the imaging of two adjacent emitter elements onto the corresponding macrocells with their sensor elements in an identical poor position, as described above. For example, four emitter elements with their macrocells are used, with the number of rows of sensor elements of the macrocells being eighteen. As a result, the imaging of an emitter element onto a macrocell repeats identically from the fourth macrocell onwards, assuming theoretically perfect imaging or the optics image with the same optical errors in spatially adjacent macrocells.If one emitter element images to a bad location on the macrocell, at least the other three emitter elements image to another, better location on the macrocell.

[0031] In addition, a further LIDAR measuring system is proposed according to patent claim 4. The dependent claims represent advantageous embodiments of the LIDAR measuring system.

[0032] The previous statements regarding patent claims 1, 2, and 3 apply identically to this LIDAR measurement system. Accordingly, the various LIDAR measurement systems have many technical and feature-related overlaps.

[0033] For a row number of N emitter elements and the corresponding N macrocells, the row number of the sensor elements of the N macrocells is determined by (m · N) + k, where M is an integer and k is an integer between 1 and N - 1. The number M and the number k can be freely selected.

[0034] Advantageous design variants of the LIDAR measuring system are explained below.

[0035] Particularly advantageously, a spacing, for example, in the form of one or more empty rows of sensor elements, can be formed between two macrocells. These can be counted cell by cell or according to the variants described above, or not counted at all. A corresponding empty row can be wider or narrower than a row containing sensor elements. This means that the width of the empty row can be larger or smaller than the spacing between two adjacent sensor elements.

[0036] It is further proposed that adjacent sensor elements of odd order have an offset and adjacent sensor elements of even order have no offset.

[0037] An element, i.e., a sensor element or emitter element, has a direct neighbor, which is the first-order neighbor. The element following this neighbor corresponds to the second-order neighbor, whereupon the element after that corresponds to the third-order neighbor, and so on. The neighborhood advantageously refers to the row-wise or column-wise neighborhood. In other words, this means that a sensor element is offset from its neighbor, with the offset being canceled out again with the next sensor element. Elements adjacent in the row direction are advantageously offset in the column direction, with elements adjacent in the column direction preferably being offset from one another in the row direction.

[0038] In an alternative variant, the offset is added row by row or column by column. Furthermore, the offset value can vary from row to row or column to column. The row and column shape thus allows for not only a rectangular pattern, but also other pattern shapes, such as a diamond or hexagon.

[0039] Advantageously, sensor elements adjacent in the column direction have an offset pointing in the row direction.

[0040] It is particularly advantageous for sensor elements adjacent in the row direction to have an offset in the column direction.

[0041] By offsetting adjacent sensor elements in this way in an orthogonal direction, improved coverage on the chip is achieved. In particular, hexagonal sensor elements achieve a particularly high detector area per chip area.

[0042] Advantageous values ​​for an offset are, for example, 1 / 3 or 1 / 2 of the distance between the sensor elements.

[0043] In an advantageous embodiment, the sensor elements are circular, square or hexagonal.

[0044] A circular or square design of the sensor elements is particularly advantageous for SPADs from a manufacturing perspective. In contrast, the use of hexagonal sensor elements achieves a relatively large detection area. The sensor elements, especially SPADS, are advantageously rounded at the corners.

[0045] According to the invention, the columns of emitter elements of the LIDAR transmitting unit and the columns of sensor elements of the LIDAR receiving unit have an angle a to each other or are formed parallel to each other.

[0046] In a parallel arrangement, it is already possible to decorrelate the emitter elements and the sensor elements by the distance between the sensor elements. Rotating the columns or rows by an angle α allows for the introduction of a further component of decorrelation. Alternatively, the angle can also be determined based on the rows of sensor elements and emitter elements.

[0047] The angle α rotates around a surface normal to the focal plane array of the units. This advantageously prevents the planes of the focal plane arrays of the LIDAR transmitter unit and the LIDAR receiver unit from being tilted relative to each other. The emitter elements and the sensor elements thus remain on the same plane or on two mutually parallel planes.

[0048] According to the invention, the angle α is between 0 and 45 degrees, preferably between 2 degrees and 10 degrees.

[0049] In these areas, a particularly advantageous decorrelation is possible to provide optimal illumination of the sensor elements.

[0050] In addition, a LIDAR receiving unit according to claim 10 is proposed, which is suitable for a LIDAR measuring system according to at least one of the previous embodiments or according to a LIDAR measuring system according to claims 1 to 9.

[0051] The previous and following statements regarding the LIDAR receiving unit apply accordingly to the LIDAR receiving unit.

[0052] The LIDAR measurement system and the LIDAR receiver unit are further explained using several examples. They show: Fig. 1 a schematic representation of a LIDAR measuring system; Fig. 2 a partial view of a LIDAR receiving unit and a LIDAR transmitting unit; Fig. 3 Representation of different imaging options for a correlated LIDAR measurement system; Fig. 4 first variant of a decorrelated LIDAR measurement system; Fig. 5 second variant of a decorrelated LIDAR measurement system; Fig. 6 imaging options of the decorrelated LIDAR measurement system according to Fig. 5; Fig. 7 third variant of a decorrelated LIDAR measurement system; Fig. 8 fourth variant of a decorrelated LIDAR measurement system.

[0053] In the Fig. 1 shows a LIDAR measuring system 10 with a LIDAR receiver unit 12 and a LIDAR transmitter unit 14. The LIDAR measuring system 10 also includes a receiver optics 16 and a transmitter optics 18. This LIDAR measuring system 10 is intended for static mounting on a motor vehicle to monitor an environment and determine the distance and movement of an object 20 from the motor vehicle. Such a measuring system can be used, for example, for autonomous driving. The operating principle is as follows.

[0054] The LIDAR transmitter unit 14 has emitter elements 22, which emit laser light in the form of light pulses. These emitter elements 22 can be formed, for example, by one or more vertical cavity surface emitting lasers (VCSELs). A pulse 24 emitted by an emitter element 22 passes through the transmitter optics 18, is reflected by an object 20, and is guided via a receiver optics 16 to one of several sensor elements 26. Such a sensor element can be formed, for example, by a single photon avalanche diode (SPAD).

[0055] In the Fig. 1, only one beam 25 is shown for the purpose of simplicity, illustrating the path of pulse 24. With the aid of optics 16 and 18 and the multitude of emitter elements 22 and sensor elements 26, the measuring system 10 can scan a space for objects. The corresponding optics 16 and 18 ultimately assign a specific solid angle to each emitter element 22 and each sensor element 26. A light pulse 24 detected by a sensor element 26 is read out by a readout element 28 and forwarded to an evaluation unit 30, which, among other things, has a memory element. The time of flight principle, also known as TOF, is used to determine the distance of object 20 from the motor vehicle. The emitted pulse is linked to the time elapsed until it arrives at the receiving unit 12, from which the path of the light pulse 24 can be determined.The corresponding coordination of the ongoing processes is implemented by the control unit 32. The readout element in this embodiment is a time-to-digital converter (TDC), which fills a memory element that displays a histogram. However, these explanations are very basic and are intended only to illustrate the general principle. This embodiment is by no means limiting for the electronic structure of the measuring system. In order not to exceed the scope of this document, not all interactions between the respective electronic components and their specific structure can be presented and explained. The LIDAR measuring system is connected to other components of the motor vehicle via a connection 34, via which the corresponding data can be transmitted.

[0056] The Fig. 2 shows a partial top view of the LIDAR receiving unit 12 and the corresponding section of the LIDAR transmitting unit 14. The emitter elements 22 shown map accordingly onto the shown section of the receiving unit 12.

[0057] In this illustration, the receiving unit has four macrocells 1, 2, 3, 4, which are assigned to the four emitter elements 22. The actual mapping of the respective emitter element 22 onto the receiving unit 12 is illustrated by a circle 36. This represents Fig. 2 shows the theoretical imaging position of the emitter elements 22 onto the receiving unit 12, assuming that the laser light 36 is reflected from an object at infinity or at maximum detection range and impinges on the receiving unit 12. The circle 36 is shown hatched.

[0058] Each emitter element 22 is assigned a plurality of sensor elements 26, with only some of the sensor elements 26 being provided with a reference symbol to ensure clarity. The emitter element 22 is larger than the sensor element 26, whereby the laser light 36 illuminates or can illuminate a plurality of sensor elements 26.

[0059] A possible deviation of the incoming laser light, for example due to optical effects or other effects such as aging effects, is indicated by a circle 38 within which the incoming laser light 36 can move. The sensor elements 26 can be individually activated and, accordingly, individually deactivated, so that non-illuminated sensor elements 26 are deactivated to reduce the detection of ambient radiation.

[0060] The sensor elements are grouped into macrocells 1, 2, 3, 4, whereby a macrocell 1, 2, 3, 4 and an emitter element 22 are assigned to each other. This assignment is illustrated by Fig. 2 Each sensor element 26 is labeled with the number of the corresponding macrocell 1, 2, 3, 4. Accordingly, an emitter element 22 only maps to sensor elements 22 of the respective macrocell 1, 2, 3, 4. The uppermost emitter element 22 is assigned the sensor elements 26 with the number 1, which form macrocell 1; the sensor elements of macrocell 2 are assigned to the emitter element 22 below, and so on.

[0061] The sensor elements are hexagonal in shape. Their corners are preferably rounded. The macrocells, emitter elements, and sensor elements are arranged in a row-column configuration. The columns of emitter elements and macrocells are labeled with uppercase Roman numerals, and the rows are labeled with uppercase Latin letters. The columns of sensor elements are labeled with lowercase Roman numerals, and the rows of sensor elements are labeled with lowercase Latin letters.

[0062] Adjacent sensor elements in a column are offset in the row direction, resulting in a hexagonal shape. Adjacent sensor elements of the first order and further odd orders are offset in the row direction, whereas adjacent sensor elements of the second order and further even orders are not offset from each other in the row direction.

[0063] In the Fig. Figure 3 shows several imaging variants for a correlated LIDAR measurement system. This LIDAR measurement system comprises, for example, four rows of sensor elements 26 per emitter element or macrocell. The incoming laser light from an emitter element 22 is also indicated by the circle 36. The sensor elements 26 can be individually activated and deactivated, with only the active sensor elements 26 transmitting measured values ​​to the evaluation electronics.

[0064] Sensor elements 26 in which only a small portion of the detection area is illuminated increase the detected ambient radiation disproportionately compared to the measurable laser light actively emitted by an emitter element 22. Active sensor elements 26 are shown hatched, whereas inactive sensor elements 26 are drawn as a hexagonal frame.

[0065] The correlation of the LIDAR measuring system 10 can be determined using the Fig. 3 clearly. A comparison of the incoming laser light 36 from macrocell 1 and macrocell 2 reveals that it images identically onto the sensor elements 26 at the macrocells. This applies to the Fig. 3a, which shows the theoretical imaging position of the LIDAR transmitting unit 14 on the LIDA receiving unit 12, for the Fig. 3b, which represents the worst possible deflection of the incoming laser light 24 as well as the Fig. 3c, which shows the best possible deflection for the incoming laser light.

[0066] In the Fig. 3a, two sensor elements 26 are almost completely illuminated. Typically, it is worthwhile to activate a sensor element if it has an illuminated area of ​​more than 50 percent. Fig. 3a, the sensor elements 26 which are only partially illuminated are therefore deactivated. Fig. 3b, the worst case scenario, although six sensor elements are hit by the laser light 24, only one sensor element 26 is sufficiently illuminated. In comparison with the illumination of Fig. 1, the ratio of measurement signal to noise floor is negatively reduced. Furthermore, activation of the additional five sensor elements 26, which are only partially illuminated, would result in a deterioration of the measurement signal compared to a noise floor.

[0067] The best possible shift of the laser light 24 is in the Fig. 3c, where three sensor elements 26 are sufficiently illuminated, i.e. with an area of ​​over 50 percent. Fig. 3a to 3c illustrate corresponding deflections of the laser light 36, which are caused, for example, by optical imaging errors.

[0068] In the correlated LIDAR measurement system described, such deflections lead to a significant improvement or deterioration in detection performance. The latter should be avoided due to variation in the manufacturing process and for economic reasons.

[0069] One of the reasons for such a uniform shift is that typical manufacturing inaccuracies can occur in the optics, i.e. in the receiving optics 16 and the transmitting optics 18, which cause a slight deflection of the outgoing or incoming laser light. Such aberrations are essentially identical for certain areas of the optics or at least correlated with each other for certain areas. Due to the short distance between the sensor elements, optical aberrations for these closely spaced sensor elements are correlated with each other. This means that a shift due to an optical aberration shifts the laser light 36 essentially identically for neighboring macrocells. If a bad area of ​​a macrocell is hit in a correlated LIDAR measuring system, this is bad for all macrocells in this area.Such an effect is to be avoided by the following explanations of a decorrelated LIDAR measurement system.

[0070] In the Fig. 4 shows a decorrelated LIDAR measurement system 10. Here, too, only a section of a LIDAR receiver unit 12 with four macrocells 1, 2, 3, and 4, which are assigned to four emitter elements 22, is shown for the LIDAR measurement system 10. The incoming laser light 36 is shown as a representative of the emitter elements 22, as is the circle 38, which represents the possible boundary areas for the laser light 36.

[0071] Here too, in the Fig. 4a the theoretical image on the LIDAR receiving unit after reflection of the laser light 36 from an object at infinity or at maximum detection range. Fig. 4b shows the best possible image of the laser light 36 on the LIDAR receiver unit and the Fig. 4c shows the worst possible variant. Each figure is also accompanied by a table illustrating the corresponding illumination of the individual macrocells 1, 2, 3, and 4 and their sensor elements 26.

[0072] The illumination of the sensor elements 26 is shown in the table under the respective Fig. 4a, Fig. 4b and Fig. 4c. These numerical values ​​correspond to the proportion of the area of ​​the sensor element 26 that is illuminated by the laser light. The value 1 corresponds to illumination of the entire area, 0.5 to an illuminated area of ​​50%, and 0 to an illuminated area of ​​0%. As already mentioned, only sensor elements 26 are activated where an area of ​​more than 50% is illuminated by the laser light.

[0073] The active sensor elements 26 are also shown hatched here, with the illuminated areas of the active sensor elements 26 being added together for each macrocell 1, 2, 3, 4. In the Fig. 4, the arrangement of the sensor elements 26 within the circle 38 of adjacent macrocells 1, 2, 3, 4 is different. A deflection of the laser light 36 has different effects for different macrocells 1, 2, 3, 4. This is also evident in Fig. 4a, in which the laser light 36 impinges on two different arrangement variants of the sensor elements 26 in adjacent macrocells 1, 2, 3, and 4. The arrangement of the sensor elements 26 is repeated every second macrocell 1, 2, 3, and 4. The odd-numbered macrocells 1, 3 and the even-numbered macrocells 2, 4 each have the same illumination pattern.

[0074] In particular, in the standard position according to Fig. 4a, two sensor elements 26 per macrocell 1, 2, 3, 4 are fully illuminated, resulting in a total illumination of 8.0. In the Fig. 4b, which represents the best possible shift of the laser light 36, three sensor elements are active per macrocell, resulting in a total illumination of 11.4. In the Fig. Figure 4c shows the worst possible position for illumination by the emitter elements 22. In macrocell 1 and macrocell 3, three sensor elements 26 are almost completely illuminated, whereas in macrocells 2 and 4, only one sensor element 26 is active and illuminated at the same time. However, the total illumination is still 7.9, which is only 0.1 below the theoretical figure. The decorrelation ensures sufficient illumination at all times, even if deflections of the laser light 36 occur.

[0075] The decorrelation of the example from Fig. 4 is achieved by using 19 rows of sensor elements, which are assigned to 4 macrocells or 4 emitter elements. The number 19 is not a multiple of the number 4. The number of rows of sensor elements 26 is not equal to a multiple of the number of corresponding rows of emitter elements. Likewise, the distance D between adjacent emitter elements 22 is not an integer multiple of the distance d between two rows of sensor elements 26. The distances d and D are in the Fig. 4a. The variables according to the formula given above in the general description are N=4, M=4, and K=3.

[0076] In another variant according to the Fig. 5 and Fig. 6, 17 rows of sensor elements 26 are arranged corresponding to four rows of emitter elements 22. The Fig. 5 shows the comparison of a section of the LIDAR transmitting unit 14 with a corresponding section of the LIDAR receiving unit 12. Here, too, the assignment of the macrocells 1, 2, 3, 4 to the emitter elements 22 is clearly shown.

[0077] In further development of the design variant according to Fig. 4 maps each emitter element to a different arrangement of sensor elements. These arrangements are repeated, for example, for every fourth macrocell.

[0078] According to Fig. 6a, Fig. 6b and Fig. Figure 6c again describes the three imaging variants. The different numerical values ​​for the illumination of each of the macrocells 1, 2, 3, and 4 and their active sensor elements 26 further illustrate the different illumination patterns.

[0079] Each macrocell 1, 2, 3, and 4 experiences its own illuminance. For theoretical, worst-case, and best-case incident laser light, the total illuminance variation is between 8.9 and 9.2. Regardless of the deflection of the laser light due to optical aberrations, illuminating a group of four macrocells results in an essentially unchanged illuminance.

[0080] Thanks to decorrelation, the LIDAR measurement system 10 is independent of any imaging errors in the optics used. Manufacturing costs can be reduced by using cheaper optics while maintaining the same functionality.

[0081] The spatial angle is thus sufficiently well illuminated at all times, which ensures reliable object detection. Fig. 6, 51 sensor elements 26 are provided to ensure optimal illumination and detection. Sensor elements 26 that lie outside the theoretical imaging range of the emitter elements can, for example, be omitted during production. However, due to the manufacturing processes, it is advantageous to simply manufacture them. Alternatively, these SPADs can also be used as aperture SPADs, which are active in a close range where a self-glare effect can occur. Such self-glare can, for example, be triggered by a front screen that partially reflects the emitted laser light. The aperture SPADs are adapted accordingly, e.g., by a coating, so that they are not triggered by this reflection or are triggered with a lower probability.

[0082] In the Fig. Figure 7 shows a further embodiment variant that uses essentially square sensor elements instead of hexagonal ones. These square sensor elements have rounded corners.

[0083] In this example, three columns i, ii, iii and 13 rows are formed compared to four rows of emitter elements 22. This ratio is also not an integer multiple of the number of rows or the number of emitter elements 22. The spacing D of the emitter elements is also not an integer multiple of the spacing d of the sensor elements.

[0084] The offset is generally defined as the distance from a point on an element to the same point on the neighboring element. This point can be, for example, the center or an edge of the respective element.

[0085] In a row a of sensor elements 26 of the LIDAR receiver unit 12, a corresponding column offset is shown for adjacent sensor elements 22 in the row direction. Column ii is shifted downward by approximately 50 percent, i.e., in the column direction or perpendicular to the row direction. The next adjacent sensor element 26 in column iii is not shifted relative to column i.

[0086] Even-order sensor elements adjacent to each other in a row are not shifted relative to each other; odd-order sensor elements adjacent to each other in a row are shifted relative to each other in the column direction. The illumination structure also differs for each macrocell in this decorrelated LIDAR measurement system 10.

[0087] In the Fig. Figure 8 shows another variant for a hexagonal pattern. This essentially corresponds to the previously described hexagonal variants according to Fig. 4 or Fig. 5 and Fig.6. In the section of the sensor unit, 15 rows of sensor elements 26 are assigned to the four emitter elements 22. The sensor elements are rotated by an angle α in their hexagonal arrangement. The rotation occurs around a normal to the surface of the focal plane array. This angle α is chosen as an example to be 6.9 degrees. However, angles between 0 and 45 degrees are also possible, with the angle α preferably being between 2 and 10 degrees. In particular, the column direction sr of the macrocells 1, 2, 3, 4 or the sensor elements 26 has an angle α relative to the column direction SR of the emitter elements 22.

[0088] The above explanations are based on a measuring system that, for example, has a transmitting unit and a receiving unit arranged to its right. The arrangement of the units above or diagonally to each other is thus implicitly included and requires no separate description. Rotation of one or both units is also included in the above descriptions. This can also be the rotation of a chip within a unit. Reference symbol 1,2,3,4 macrocell 10 LIDAR measuring system 12 LIDAR receiver unit 14 LIDAR transmitter unit 16 Receiving optics 18 Transmitter optics 20 objects 22 Emitter element, VCSEL 24 laser light, pulse 25 beam 26 Sensor element 28 Readout element 30 Evaluation unit 32 Control unit 34 Connection 36 circle, laser light 38 Circle, boundary Incoming laser light I, II, III, column macrocell, emitter element i, ii, iii, column sensor element A, B, C row macrocell, emitter element a, b, c line sensor element d distance D Distance α angle sr column direction macrocell, sensor element SR column direction emitter element

Claims

[1] LIDAR measuring system (10) with a LIDAR transmitting unit (14) and a LIDAR receiving unit (12), which is designed in a focal plane array arrangement, wherein - The LIDAR receiving unit (12) has a plurality of sensor elements (26) and wherein - The LIDAR transmitting unit (14) has a plurality of emitter elements (22), wherein - several sensor elements (26) form a macrocell (1, 2, 3, 4), wherein the macrocell (1, 2, 3, 4) is assigned to a single emitter element (22), characterized by that the distance (D) between two adjacent emitter elements (22) is not equal to an integer multiple of the distance (d) between two adjacent sensor elements (26), wherein the columns of emitter elements (22) of the LIDAR transmitting unit (14) and the columns of the sensor elements (26) of the LIDAR receiving unit (12) have an angle α to one another and wherein the angle α is between 0° and 45°. [2] LIDAR measuring system (10) according to claim 1, characterized by , that - the emitter elements (22) and the macrocells (1, 2, 3, 4) are each arranged in a kind of row-column arrangement and wherein - the sensor elements (26) are also arranged in a kind of row-column arrangement. [3] LIDAR measuring system (10) according to the preamble of claim 1, characterized by , that - the emitter elements (22) and the macrocells (1, 2, 3, 4) are each arranged in a kind of row-column arrangement and wherein - the sensor elements (26) are also arranged in a kind of row-column arrangement, characterized by that the common number of rows of the sensor elements (26) of several adjacent macrocells (1,2,3,4) is not equal to the integer multiple of the associated emitter elements (22). [4] LIDAR measuring system (10) according to the preamble of claim 3, characterized bythat with a row number of N emitter elements (22) and the associated N macrocells (1,2,3,4), the row number of the sensor elements (26) of the N macrocells (1,2,3,4) is determined by (m · N) + k, where m is an integer and k is an integer between 1 and N - 1. [5] LIDAR measuring system (10) according to one of claims 1 to 4, characterized by that adjacent sensor elements (26) of odd order have an offset and adjacent sensor elements (26) of even order have no offset. [6] LIDAR measuring system (10) according to one of claims 1 to 5, characterized by that sensor elements (26) adjacent to each other in columns have a row-wise offset. [7] LIDAR measuring system (10) according to one of claims 1 to 6, characterized by that sensor elements (26) adjacent in the row direction have an offset pointing in the column direction. [8] LIDAR measuring system (10) according to claim 1, characterized by that the angle α is between 2° and 10°. [9] LIDAR receiving unit (12) suitable for a LIDAR measuring system (10) according to one of claims 1 to 8.

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