Method for identifying a parking space by means of an ultrasonic sensor

Abstract

The invention relates to a method for identifying a parking space by means of at least one ultrasonic sensor of a vehicle.

Description

Technical Field

[0001] This invention relates to a method for identifying parking spaces using one or more ultrasonic sensors. Background Technology

[0002] It is known that ultrasonic sensors are used to detect information about the surrounding environment within a vehicle's area, for example, to detect the distance to other objects when parking.

[0003] Similarly, it is known that trilateration, based on information from multiple ultrasonic sensors, can be used to identify parking spaces. Trilateration not only determines the distance between objects but also their spatial orientation.

[0004] The known disadvantages of parking space identification methods are that they are computationally complex, and the trilateration method is prone to errors due to the inaccuracy of the ranging system and the influence of noise. Summary of the Invention

[0005] Therefore, the objective of this invention is to provide a method for identifying parking spaces using one or more ultrasonic sensors, a method that requires low computational and storage costs and is less prone to errors.

[0006] This task is accomplished by a method having the features described in independent claim 1. Preferred embodiments are the subject of dependent claims. A system for identifying parking spaces using one or more ultrasonic sensors is the subject of co-independent claim 10, while a vehicle having such a system is the subject of co-independent claim 15.

[0007] According to a first viewpoint, the present invention relates to a method for identifying parking spaces by means of at least one ultrasonic sensor mounted on a vehicle. The method includes the following steps:

[0008] First, the vehicle's ultrasonic sensor sends an ultrasonic signal. Here, only one ultrasonic sensor can send an ultrasonic signal, or multiple ultrasonic sensors can send their respective ultrasonic signals simultaneously or sequentially.

[0009] Then, the reflected signal portion of the ultrasonic signal is received by the ultrasonic sensor. The reflected signal portion (hereinafter also referred to as the echo) can be received by either the same ultrasonic sensor that sent the ultrasonic signal or by another ultrasonic sensor (so-called cross echo).

[0010] In addition, a grid associated with the vehicle's surrounding environment is provided. The grid has multiple cells, each assigned a partition of the vehicle's surrounding environment, and each cell is assigned an occupancy value. The occupancy value of a cell, for example, represents the frequency to which the received echo is assigned. Preferably, the grid or its cells move with the corresponding positions of the vehicle; that is, the grid has a fixed reference relative to the vehicle's position, rather than relating to a fixed location of the surrounding environment.

[0011] Subsequently, based on the transmission time of the ultrasonic signal between the transmitted and received reflected signal portions, the reflected signal portion is assigned to a set of cells forming a grid. The distance between the objects causing the reflection can be determined using the ultrasonic sensor based on the transmission time. Based on the knowledge of the ultrasonic sensor's position on the vehicle and the vehicle's distance measurement data, the received reflected signal portion can be assigned to a set of cells. Based on this assignment, the occupancy value of each cell to which the reflected signal portion is assigned can be increased by a specific value. This value can be a fixed value or derived from the characteristics of the reflected signal portion.

[0012] Subsequently, based on the cell occupancy values ​​of the specified cell set, and following these steps, the occupancy information is determined:

[0013] First, identify the cell with the highest occupancy value in the cell set. In other words, determine the cell with the highest occupancy value in the cell group to which the previous echo was assigned.

[0014] The highest occupancy value is then compared with a first threshold.

[0015] If the highest occupied value exceeds the first threshold, the counter assigned to the cell with the highest occupied value is changed by an increment value.

[0016] The counter is then compared with a second threshold, and the occupancy status of the cell is determined based on the comparison result. In particular, if the counter is greater than the second threshold, the cell is marked as occupied, meaning that a reflective object exists within the area of ​​the cell.

[0017] The steps described above—sending ultrasonic signals and receiving echoes, allocating the echoes to a set of cells formed by multiple cells in the grid, increasing the occupancy value of the cell set, and determining the occupancy information—are repeated multiple times.

[0018] Subsequently, parking spaces are identified based on the occupancy status of the grid cells. Here, for a parking process, the surrounding environmental areas with an occupancy status of "unoccupied" are assessed as "unoccupied".

[0019] The technical advantage of the method according to the present invention is that it improves the identification of unoccupied areas in the vehicle's surrounding environment that can be used for a parking process in terms of computational performance and memory requirements. Furthermore, the method is insensitive to noise from ultrasonic sensors and can minimize the false detection / false positive rate through filtering with multiple thresholds.

[0020] According to one embodiment, the set of cells whose occupancy value increases in each transmit / receive cycle is determined by an annular portion whose central radius depends on the transmission time of the ultrasonic signal between the transmitted and received reflected signal portions. The circumferential extension of the annular portion depends on the receiving range of the ultrasonic sensor. In other words, the set of cells is determined solely by the transmission time of the ultrasonic signal between the transmission and reception points and the angular range of the ultrasonic sensor's transmission and / or reception. Therefore, the proposed method can identify parking vacancies without determining the azimuth angle indicating the direction of the received echo.

[0021] According to one embodiment, the radial width of the annular portion is determined by the tolerance values ​​of the ultrasonic sensor and / or the tolerance values ​​of the ranging system used to determine the vehicle position and / or the ultrasonic sensor position. Therefore, the width of the annular portion is determined by the inaccuracies arising from sensing technology and / or sensor information evaluation.

[0022] According to one embodiment, the cell occupancy value increases by a corresponding value based on the amplitude of the received reflected signal portion, or the cell occupancy value increases by a fixed value independently of the received reflected signal portion. If the sensor provides amplitude information, this information can be used to increase the cell occupancy value based on the amplitude. Thus, the occupancy value can be changed using the echo intensity. In the absence of usable amplitude information, the cell occupancy value can be increased by a fixed value, for example, by 1.

[0023] According to one embodiment, multiple different occupancy information are determined in parallel, and these multiple different occupancy information are determined in parallel based on information measured by multiple ultrasonic sensors installed at different locations on the vehicle. In other words, the temporally parallel information provided by different ultrasonic sensors installed at different locations on the vehicle can be used to change the occupancy value of a cell, and the derived occupancy information can be obtained after the occupancy value is changed. Thus, an ambient environment image can be generated in parallel using multiple sensor information, or an existing ambient environment image can be updated.

[0024] According to one embodiment, compensation is made for the vehicle's own motion that occurs during the time interval between the transmission and reception of ultrasonic signals. This compensates for changes in the vehicle's position relative to stationary objects in the surrounding environment that occur during the time interval between ultrasonic signal transmission and reception.

[0025] According to one embodiment, cross-echoes between different ultrasonic sensors are also evaluated to determine occupancy information. In other words, the portion of the reflected signal received by another ultrasonic sensor, different from the transmitting sensor, also helps to determine occupancy information, thereby improving the identification of parking spaces.

[0026] According to one embodiment, the grid is a grid that moves with the vehicle. For example, the grid may have a length and / or width corresponding to 3 to 6 times the length of the vehicle, and an extension dimension of, for example, 20 meters by 20 meters. Thus, the grid can enclose the surrounding environment area adjacent to the vehicle that can be detected by ultrasonic sensors installed on the vehicle. This saves memory and computing resources.

[0027] According to one embodiment, cell occupancy values ​​and / or counters assigned to cells and / or cell occupancy status are stored in a circular buffer. Thus, information related to grid cells can be stored in a memory-optimized manner.

[0028] According to another perspective, the present invention relates to a system for identifying parking spaces, the system comprising at least an ultrasonic sensor and a computing unit configured to evaluate information provided by the ultrasonic sensor. The system is configured to perform the following steps:

[0029] a) An ultrasonic signal is sent by the vehicle's ultrasonic sensor;

[0030] b) A reflected signal portion of the ultrasonic signal received by the ultrasonic sensor;

[0031] c) Provide a grid relating to a region of the vehicle’s surrounding environment, wherein the grid comprises a plurality of cells, wherein each cell is assigned a partition of the region of the vehicle’s surrounding environment and each cell is assigned an occupancy value;

[0032] d) Based on the transmission time of the ultrasonic signal between the transmitting and receiving reflected signal portions, the reflected signal portion is assigned to a set of cells formed by multiple cells of the grid, wherein the cell occupancy value assigned to the reflected signal portion is increased by a specific value accordingly.

[0033] e) Determine occupancy information based on the cell occupancy values ​​of the cell set using a calculation unit, the method being:

[0034] 1. Identify the cell in the cell set with the highest occupied value;

[0035] 2. Compare the highest occupancy value with a first threshold;

[0036] 3. If the highest occupancy value exceeds the first threshold, the counter assigned to the highest occupancy value is incremented by one value; and

[0037] 4. Compare the counter with a second threshold, and determine the cell occupancy status based on the comparison result;

[0038] f) Repeat steps a), b), d), and e) multiple times; and

[0039] g) Implement parking space identification based on the occupancy status of each cell in the grid.

[0040] According to one embodiment of the system, the calculation unit is configured such that the set of cells for which the occupancy value increases in each transmit / receive cycle is determined by an annular portion. The central radius of this annular portion depends on the transmission time of the ultrasonic signal between the transmitted and received reflected signal portions, and the circumferential extension of this annular portion depends on the receiving range of the ultrasonic sensor. In other words, the set of cells is determined solely by the transmission time of the ultrasonic signal between the transmission and reception points and the angular range of the ultrasonic sensor's transmission and / or reception. Therefore, the proposed method can identify parking vacancies without determining the azimuth angle indicating the direction of the received echo.

[0041] According to one embodiment of the system, the calculation unit is configured such that the set of cells whose occupancy value increases in each transmit / receive cycle is determined by an annular portion, the radial width of which is determined by the tolerance value of the ultrasonic sensor and / or by the tolerance value of the ranging system used to determine the position of the vehicle and / or the ultrasonic sensor. Therefore, the width of the annular portion is determined by assessing inaccuracies arising from sensing technology or sensor information.

[0042] According to one embodiment of the system, the computing unit is configured to determine multiple different occupancy information in parallel, and the multiple different occupancy information is determined in parallel based on information measured by multiple ultrasonic sensors installed at different locations on the vehicle. This allows for the parallel generation of an ambient environment image or the updating of an existing ambient environment image based on information from multiple sensors.

[0043] According to one embodiment of the system, the computing unit is configured to compensate for the vehicle's own motion that occurs during the time interval between the transmission and reception of ultrasonic signals. This allows for compensation for positional changes of the vehicle relative to stationary objects in the surrounding environment that occur during the time interval between the transmission and reception of ultrasonic signals.

[0044] According to another viewpoint, the present invention relates to a vehicle equipped with a parking space recognition system according to one of the previously described embodiments.

[0045] In the context of this invention, the terms “approximately,” “substantially,” or “roughly” refer to variations in which the error from the respective precise values ​​is + / -10%, preferably + / -5%, and / or the error is inconsequential to the function.

[0046] Other structural forms, advantages, and application possibilities of the invention also arise from the following description and drawings of the embodiments. Here, all described and / or illustrated features, whether independently or in arbitrary combinations, constitute the essential subject matter of the invention and are independent of their summary in the claims or their recapitulation. The content of the claims is also part of the related description. Attached Figure Description

[0047] The present invention will now be described in detail with reference to the accompanying drawings of the embodiments. Wherein:

[0048] Figure 1 This diagram illustrates a typical scenario where a vehicle with multiple ultrasonic sensors passes through a longitudinally parked parking space.

[0049] Figure 2 This diagram illustrates a typical scenario where a vehicle's surrounding environment is divided into grids, and a diagram illustrating the detection of an object within the surrounding environment using an ultrasonic sensor.

[0050] Figure 3 A typical diagram showing multiple ultrasonic echoes received in the area surrounding a vehicle is presented, where these echoes are marked on a two-dimensional map according to their location.

[0051] Figure 4 A typical flowchart illustrating a method for determining occupancy information assigned to grid cells; and

[0052] Figure 5 The flowchart illustrates the steps of a method for identifying parking spaces in the area surrounding a vehicle.

[0053] List of reference numerals in the attached diagram:

[0054] 1 vehicle

[0055] 2 Ultrasonic Sensors

[0056] BW occupancy value

[0057] BW 最高 Maximum occupancy value

[0058] ε tolerance value

[0059] n counter

[0060] r center radius

[0061] R grid

[0062] T1 First Threshold

[0063] T2 Second Threshold

[0064] Z cell Detailed Implementation

[0065] Figure 1 This illustrates a typical parking scenario where vehicle 1 drives past multiple longitudinal parking spaces. At this point, one parking space between two vehicles is unoccupied. It is understood that this invention is not limited to longitudinal parking scenarios but can also be applied to lateral parking scenarios.

[0066] Vehicle 1 has multiple ultrasonic sensors 2 capable of detecting information about the surrounding environment. The illustrated embodiment shows two ultrasonic sensors 2. It is understood that more than two ultrasonic sensors can be installed on vehicle 1. The ultrasonic sensors 2 are particularly configured to detect information about the surrounding environment in front of, behind, and to the sides of vehicle 1. The ultrasonic sensors 2 are specifically configured to transmit an ultrasonic signal in one transmission cycle and receive the signal portion of the ultrasonic signal reflected from objects in the environment surrounding vehicle 1 in a subsequent reception cycle. The time span between transmitting the ultrasonic signal and receiving the reflected signal portion is a measure of the distance between the object and the ultrasonic sensor 2. Information about objects in the area surrounding vehicle 1 can thus be determined.

[0067] Figure 2 The surrounding environment area 3 of vehicle 1 is shown. This area is divided into surrounding environment partitions by a grid R, which may have a predetermined fixed extension size, such as 20 meters x 20 meters, in both the x and y directions. The grid R has multiple cells Z, which are directly adjacent to each other in a checkerboard pattern, thereby associating each cell Z with a specific surrounding environment partition. The grid R with cells Z is configured to locally and discretely reproduce the surrounding environment information detected by one or more ultrasonic sensors 2 in multiple transmission and reception cycles, thereby providing a discrete image of the surrounding environment.

[0068] exist Figure 2 In the diagram, the solid circular arc represents the detection area of ​​ultrasonic sensor 2. The center radius r can be determined based on the transmission time of the ultrasonic signal between the transmission point and the receiving reflection point. The angle α of the arc extension is determined by the detection range of ultrasonic sensor 2.

[0069] Both the ultrasonic sensor 2 and the ranging unit of the vehicle 1, used to determine the local position of vehicle 1, have certain tolerances. Therefore, the position of the detected object relative to vehicle 1 will have some inaccuracy. This inaccuracy is accounted for by the tolerance value ε. If an object is detected at a distance r from the ultrasonic sensor 2, due to the aforementioned inaccuracy, the object may be located within the range of r ± ε, i.e., within an arc-shaped area with a width of 2ε. This arc-shaped area... Figure 2 The two arcs are represented by dashed lines.

[0070] In most cases, a single ultrasonic sensor 2 cannot determine the azimuth angle of the reflected signal portion, so the received reflection may originate from any direction within the receiving range of the ultrasonic sensor 2. Therefore, the reflection may originate from an object located in an arc-shaped area with a width of 2ε. Figure 2 In the example, the object causing the reflection may therefore be located in cell Z, which is marked with a shadow.

[0071] Figure 3 The diagram shows a localized representation of reflections in the surrounding environment around vehicle 1, displayed as points. As can be seen, noise and other adverse effects contribute to a false detection rate, hindering or impeding the identification of parking spaces. A detection algorithm is proposed below, which reduces the false detection rate while simultaneously lowering the demands on computing hardware (processing performance and / or memory).

[0072] Figure 4 A flowchart of a detection algorithm according to an embodiment of the present invention is shown.

[0073] After starting the algorithm (S10), an empty cell list is first initialized, and a first threshold T1 and a second threshold T2 are determined. Subsequently, a transmit and receive cycle is implemented, in which one or more ultrasonic sensors 2 transmit an ultrasonic signal, and if a reflective object exists within the detection range of the ultrasonic sensor 2, a portion of the reflected signal is received (S11).

[0074] Upon receiving the reflected signal portion, a set of cells assigned to the ultrasonic echo is determined. As previously mentioned, this may take into account, for example, the transmission time of the ultrasonic signal between the time of transmitting the ultrasonic signal and the time of receiving the reflected signal portion, the tolerance value ε, and the angular range of the ultrasonic signal that the ultrasonic sensor 2 can receive.

[0075] Assign an occupancy value BW to cell Z of grid R. If it is determined in step S12 that a portion of the received reflected signal should be assigned to a cell (in... Figure 2 In the example, there are four shaded cells (Z). The cell occupancy value BW increases accordingly. This value can be determined based on the signal strength of the received reflected signal, or it can be a fixed increment, such as 1.

[0076] Subsequently, it was determined that the cell set had the highest occupied value BW. 最高 cell Z( Figure 2 In the example, these are four shaded cells Z). Note that after receiving multiple loop cycles, the grid cells Z are assigned different occupancy values ​​BW because cell Z is assigned to the set of cells with a detection result at different frequencies.

[0077] Determine the highest occupied value BW 最高 After cell Z, check the highest occupied value BW. 最高 Is it greater than the threshold T1 (S14)? If the highest occupancy value is not greater than the threshold, the algorithm ends, and upon receiving a new reflected ultrasonic signal (also called an ultrasonic echo), the relevant steps are re-executed (i.e., jump back to step S11). If the highest occupancy value BW 最高 If the value is greater than the threshold T1, then check if the allocation has the highest occupied value BW. 最高 Check if cell Z is already in the cell list (S15). If the cell with the highest occupied value is not in the cell list, cell Z is added to the cell list, and the counter n assigned to that cell is initialized with an initial value (S16). After adding cell Z to the cell list and initializing the counter, the algorithm ends. When a new reflected ultrasonic signal (also known as an ultrasonic echo) is received, the relevant steps are re-executed (i.e., jump back to step S11).

[0078] If it is determined in step S15 that the maximum occupancy value BW has been allocated. 最高 If cell Z is already included in the cell list, then the counter n assigned to cell Z is incremented by an increment value (S17), which may be 1.

[0079] After the counter n is incremented by the increment value, it is checked whether the incremented counter n is greater than the second threshold T2 (S18). If the counter is not greater than the second threshold, the correlation algorithm is terminated and the correlation steps are re-executed (i.e., jump back to step S11) when a new reflected ultrasonic signal (also known as an ultrasonic echo) is received.

[0080] If the condition checked in step S18 is met, cell Z of the assigned counter n is marked as "occupied". Subsequently, the correlation algorithm is terminated and the correlation steps are re-executed (i.e., jump back to step S11) when a new reflected ultrasonic signal (also known as an ultrasonic echo) is received.

[0081] Therefore, the algorithm described above uses a two-stage detection method to determine the occupancy status in the environment surrounding the vehicle. The two-stage method checks whether multiple detection results have been identified within a single cell area to reduce the false detection rate.

[0082] Based on the cells Z marked as occupied, it is possible to determine which areas of the surrounding environment around vehicle 1 are occupied. In other words, a grid-like image can be generated using the cell occupancy information, where unoccupied information can be used, for example, to identify parking spaces. Here, for example, it is checked whether the distance between two cells marked as occupied is greater than the length of vehicle 1, or whether the width is greater than the width of vehicle 1. Thus, it can be checked whether a parking space with a length and width suitable for vehicle 1 has been identified.

[0083] Preferably, the above algorithm is repeated after each reflected ultrasonic signal from the ultrasonic sensor 2 is received. Here, the received signals from multiple ultrasonic sensors 2 can be used to determine the cell Z occupancy status of grid R. Similarly, the cross-echoes between multiple ultrasonic sensors 2 can also be used to determine the cell Z occupancy status of grid R. This means that the reflected signal portion of the ultrasonic signal received by other ultrasonic sensors, different from the transmitting ultrasonic sensor, is also used to determine the occupancy status.

[0084] Figure 5 The diagram illustrates the steps of the method according to the present invention, which identifies parking spaces using at least one ultrasonic sensor 2 of a vehicle 1.

[0085] First, an ultrasonic signal is sent by the ultrasonic sensor 2 of vehicle 1 (S20).

[0086] Subsequently, the reflected portion of the ultrasonic signal is received by ultrasonic sensor 2 (S21). The receiving ultrasonic sensor may be the same as or different from the transmitting ultrasonic sensor 2.

[0087] In addition, a grid R (S22) is provided in relation to the area surrounding the vehicle 1. The grid R has multiple cells Z, wherein each cell Z is assigned to a partition of the area surrounding the vehicle 1, and each cell Z is assigned an occupancy value BW.

[0088] Based on the transmission time of the ultrasonic signal between the transmitting and receiving reflected signal portions, the reflected signal portion is assigned to a set of cells Z in the grid R (S23). The occupancy value BW of each cell Z to which the reflected signal portion is assigned is increased by a specific value accordingly.

[0089] Subsequently, the occupancy information is determined by the calculation unit based on the occupancy value BW of cell Z in the cell set (S24). The method includes the following steps:

[0090] 1. Determine the cell set with the highest occupied value, BW. 最高 Cell Z;

[0091] 2. Set the highest occupied value BW 最高 Compare with a first threshold T1;

[0092] 3. If the highest occupied value is BW 最高 If the value exceeds the first threshold T1, it is assigned to BW, which has the highest occupancy value. 最高 A counter Z in a cell is changed by an increment value n; and

[0093] 4. Compare the counter n with a second threshold T2, and determine the occupancy status of cell Z based on the comparison result.

[0094] Subsequently, steps S20 to S24 are repeated multiple times, i.e., the ultrasonic signal is sent / received multiple times, and occupancy information is determined based on this (S25). This is preferably performed at different locations of vehicle 1, wherein, when determining the occupancy information, the movement of vehicle 1 is compensated by vehicle ranging data.

[0095] Finally, based on the occupancy status of cell Z in grid R, parking space identification is performed (S26).

[0096] The invention has been described above with reference to embodiments. It should be noted that various modifications and variations may be made without departing from the scope of protection defined by the patent claims.

Claims

1. A method for identifying a parking space by means of at least one ultrasonic sensor (2) of a vehicle (1), the method comprising the following steps: a) sending an ultrasonic signal (S20) by the ultrasonic sensor (2) of the vehicle (1); b) receiving a reflected signal portion (S21) of the ultrasonic signal by the ultrasonic sensor (2); c) providing a grid relating to a surrounding area of the vehicle (1), wherein the grid comprises a plurality of cells, wherein each cell is assigned a section of the surrounding area of the vehicle (1), each cell is assigned an occupancy value (S22); d) assigning the reflected signal portion to a cell set (S23) formed by a plurality of cells of the grid on the basis of the transmission time of the ultrasonic signal between sending and receiving the reflected signal portion, wherein the occupancy values of the cells to which the reflected signal portion is assigned are each increased by a specific value; e) determining occupancy information (S24) on the basis of the occupancy values of the cells of the cell set by: 1) determining the cell of the cell set having the highest occupancy value; 2) comparing the highest occupancy value with a first threshold value; 3) changing a counter assigned to the cell having the highest occupancy value by an increment value if the highest occupancy value exceeds the first threshold value; and 4) comparing the counter with a second threshold value and determining an occupancy state of the cell on the basis of the comparison; f) repeatedly carrying out steps a), b), d) and e) (S25); and g) carrying out an identification of a parking space (S26) on the basis of the occupancy states of the cells of the grid. The cell set whose occupancy values are increased in each sending / receiving cycle is determined by a circular ring portion, the center radius of which depends on the transmission time of the ultrasonic signal between sending and receiving the reflected signal portion, wherein the extension of the circular ring portion in the circumferential direction depends on the reception range of the ultrasonic sensor (2). The circular ring portion has a width in the radial direction, which is determined by a tolerance value of the ultrasonic sensor (2) and / or by a tolerance value of a distance measuring system for determining the position of the vehicle (1) and / or of the ultrasonic sensor (2). The occupancy values of the cells are each increased by a value which depends on the amplitude of the received reflected signal portion, or the occupancy values of the cells are each increased by a fixed value which is independent of the received reflected signal portion. A plurality of different occupancy information is determined in parallel, a plurality of different occupancy information being determined in parallel on the basis of information determined by a plurality of ultrasonic sensors (2) arranged at different positions of the vehicle (1). A motion of the vehicle (1) itself occurring in the time period between sending and receiving of the ultrasonic signal is compensated. Cross echoes between different ultrasonic sensors (2) are also evaluated for determining the occupancy information. The grid is a grid which moves with the vehicle (1). The occupancy values of the grid and / or the counters assigned to the grid and / or the occupancy states of the grid are stored in a ring memory. The system is provided for carrying out the following steps: h) sending an ultrasonic signal by the ultrasonic sensor (2) of the vehicle (1); i) receiving a reflected signal portion of the ultrasonic signal by the ultrasonic sensor (2); ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. The method of claim 1, wherein, ​ 3. The method of claim 2, wherein, ​ 4. The method according to any one of claims 1 to 3, characterized in that, ​ 5. The method according to any one of claims 1 to 3, characterized in that, ​ 6. The method according to any one of claims 1 to 3, characterized in that, ​ 7. The method according to any one of claims 1 to 3, characterized in that, ​ 8. The method according to any one of claims 1 to 3, characterized in that, ​ 9. The method according to any one of claims 1 to 3, characterized in that, ​ 10. A system for identifying a parking space, comprising at least an ultrasonic sensor (2) and a computing unit, the computing unit being configured to evaluate information provided by the ultrasonic sensor (2), wherein ​ ​ ​ j) providing a grid relating to the area of the surroundings of the vehicle (1), wherein the grid comprises a plurality of cells, wherein each cell is assigned a section of the area of the surroundings of the vehicle (1), and each cell is assigned an occupancy value; k) assigning a reflected signal portion to a cell set formed by a plurality of cells of the grid based on the transmission time of the ultrasonic signal between the emission and the reception of the reflected signal portion, wherein the occupancy value of the cells to which the reflected signal portion is assigned is each increased by a specific value; l) determining, by means of the computing unit, occupancy information based on the occupancy values of the cells of the cell set by means of: 5) determining the cell of the cell set having the highest occupancy value; 6) comparing the highest occupancy value to a first threshold value; 7) if the highest occupancy value exceeds the first threshold value, changing a counter assigned to the cell having the highest occupancy value by an increment value; and 8) comparing the counter to a second threshold value and determining the occupancy state of the relevant cell depending on the comparison result; m) repeatedly carrying out steps a), b), d) and e) a plurality of times; and n) implementing the recognition of a parking space based on the occupancy state of the cells in the grid.

11. The system of claim 10, wherein, The computing unit is configured to determine the cell set whose occupancy value is increased in each emission / reception cycle from a circular ring section, the center radius of which depends on the transmission time of the ultrasonic signal between the emission and the reception of the reflected signal portion, and the extension of the circular ring section in the circumferential direction depends on the reception range of the ultrasonic sensor (2).

12. The system of claim 10 or 11, wherein, The computing unit is configured to determine the cell set whose occupancy value is increased in each emission / reception cycle from a circular ring section, the radial width of which is determined by the tolerance value of the ultrasonic sensor (2) and / or by the tolerance value of a distance measurement system for determining the position of the vehicle (1) and / or of the ultrasonic sensor (2).

13. The system of claim 10 or 11, wherein, The computing unit is configured to determine a plurality of different occupancy information in parallel based on information determined by a plurality of ultrasonic sensors (2) arranged at different positions of the vehicle (1).

14. The system of claim 10 or 11, wherein, The computing unit is configured to compensate for a self-motion of the vehicle (1) that occurs in the time period between the emission and the reception of the ultrasonic signal.

15. A vehicle comprising a system according to any one of claims 10 to 14.

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