WO2018086967A1

WO2018086967A1 - Parking space monitoring system

Info

Publication number: WO2018086967A1
Application number: PCT/EP2017/077911
Authority: WO
Inventors: Johannes KRAUTKREMER
Original assignee: Iee International Electronics & Engineering S.A.
Priority date: 2016-11-08
Filing date: 2017-10-31
Publication date: 2018-05-17
Also published as: LU93294B1

Abstract

Parking space monitoring system comprising at least one sensor unit for sensing an occupancy related status of a plurality of parking spaces. The sensor unit comprises a phased array radar configured to scan a plurality of parking spaces and retrieve the occupancy related status for each scanned parking space.

Description

Parking Space Monitoring System

Technical field

[0001 ] The present invention generally relates to the field of surveillance systems. The present invention more particularly relates to a surveillance system for monitoring parking space occupancy in a parking lot for automotive vehicles comprising a plurality of parking spaces.

Background of the Invention

[0002] With the increasing number of automobile vehicles, parking space is a recurrent problem for big cities. And for drivers, finding a vacant parking space is a tedious operation in both indoor and outdoor situations.

[0003] Most of the car parks now comprise more than one storey and several hundreds of parking spaces. They are commonly equipped with an information system telling the users how many vacant spaces are left before they come in, but it still takes several minutes for the drivers to find where the vacant parking spaces are.

[0004] The problem is even worse in the streets as the search for a parking space is slowed down by the traffic. These conditions force the drivers to spend more time driving while eventually getting stressed and frustrated. The extra driving time also implies more exhaust gas emission participating to the air contamination which has become a major concern worldwide.

[0005] There is therefore a need for monitoring systems for parking spaces and particularly systems that can be used either indoor and outdoor to offer automobile users information about, for example, the locations of the nearest vacant parking space.

[0006] Solutions have already been developed, for example as disclosed in WO 01/43105 A1 . The document discloses an identification system for vacancies in an indoor garage, using an optical sensor placed in the middle of a parking space, on the floor of the garage. The sensor sends a signal to a receiver vertically installed on the ceiling of the garage, in front of the sensor. When a car is parked it covers the floor sensor and cuts the signal transmission with the receiver indicating that the space is occupied. The information is further computed to indicate to the users the number and the location of all the vacant spaces.

[0007] The biggest drawback of this solution is that due to its particular configuration, it can only be installed in indoor garages and in parking spaces with a relatively low ceiling. Another drawback is that this solution requires the installation of one sensor system for each parking space, which is not cost efficient when installed in a parking lot with several hundred of parking spaces.

[0008] Another solution, in DE 10 2015 202 788 A1 , discloses a parking monitoring system for both indoor and outdoor parking lots, comprising a plurality of sensors that may be ultrasound or radar. The sensors are installed on the floor, and disposed with a spacing that is smaller to the average size of a vehicle. One sensor is activated when a vehicle is stationary on top of it. A vehicle can be detected by one or more sensors at the same time. A control unit receives information from the sensors about the presence or absence of a vehicle and creates a map of the occupied parking spaces.

[0009] This solution is efficient for detecting vehicle locations and presence in both indoor and outdoor parking lots, even where there is no marks on the floor to define the parking spaces, like in some cases on the side of the streets, but it has the disadvantage of requiring at least one sensor per parking space and eventually more than one sensor per parking space. It thus involves costly installation.

[0010] In yet another solution proposed in the state of the art document DE 10 2008 012 991 A1 , a parking monitoring system comprises a detection unit for detecting occupancy status of for parking spaces. The detection unit is installed above the floor in the center of the area of four adjacent parking spaces forming two rows. The detection unit comprises four ultrasound sensors oriented respectively in direction of each of the four parking spaces. The detection unit is further configured to identify which parking space is occupied using the ultrasound sensors.

[001 1 ] In this latter solution, the detection unit may be installed on top of a vertical pole at the height level of a standard automobile vehicle or higher than the vehicles and is adapted for both indoor and outdoor parking lots. Nevertheless, this solution requires again one sensor associated with a parking space and is only efficient when the parking spaces are disposed in series of two adjacent rows, which excludes most of the parking spaces on the side of the streets that are usually disposed in a single row along the pavement.

[0012] We have also seen solutions for outdoor parking that use a radar sensor to survey the occupancy status of a plurality of parking spaces. But these solutions require the radar to be installed at a height of approximately 9 meters above the parking spaces in order to be efficient. It is consequently not suited for indoor parking lots.

Object of the invention

[0013] It is therefore desirable to provide a parking space monitoring system that is suitable for both indoor and outdoor parking lots, and that provides an improvement to the solutions already known in the art. Particularly, it is an object of the invention to provide a parking space monitoring system that is adaptable to many parking lot configurations, and that does not involve high installation costs.

General Description of the Invention

[0014] The invention overcomes at least some of the above discussed deficiencies and disadvantages by providing a parking space monitoring system comprising at least one sensor unit for sensing an occupancy related status of a plurality of parking spaces. According to the invention, the sensor unit comprises a phased array radar configured to scan a plurality of parking spaces and retrieve the occupancy related status for each scanned parking space.

[0015] The parking space monitoring system uses a phased array radar that is capable of scanning a surface comprising several parking spaces. Phased array radars are electronically steered beam radars, they are very flexible, do not imply high installation costs and require little maintenance.

[0016] An important advantage of the invention is that by using a scanning radar technology in order to watch parking spaces, one radar can be installed to watch several parking spaces, for example five spaces in a row. This reduces by an equal amount the number of sensing units to be installed in order to monitor a given area of a parking lot, and consequently the overall costs of installation of a monitoring system. [0017] Another important advantage of the invention is that it provides flexibility in the positioning of the sensor unit. As the sensor unit is capable of scanning a monitored area, there is less strict restriction as for the alignment of the sensor unit with a particular zone of the parking space. It is therefore possible to use the parking space monitoring system according to the invention for outdoor parking places where the parking spaces are not explicitly marked with lines on the floor, like for example along street pavements.

[0018] In an embodiment of the invention, the occupancy related status may comprise occupancy and location of each parking space.

[0019] The occupancy of a parking space is defined by the two states: occupied, or vacant. The location is a relative location of the parking space according to a general map of the parking lot. These information are to be transmitted to the driver through any suitable means.

[0020] When receiving the information about where the vacant and occupied parking spaces are, the user can easily drive to these locations and does not need to keep turning around in search for a parking space. With the invention, the driver saves time and frustration. What is more, it reduces the average driving time of the automobile vehicle and its resulting pollution caused by the exhaust gas emissions, having a benefit also for the environment.

[0021 ] In embodiments of the invention, the parking space monitoring system uses e.g. pulsed radar or frequency modulated continuous wave radar (FMCW radar). In these embodiments, the occupancy related status may also comprise the distance to the parked vehicle. The distance to the parked vehicle is to be understood as the distance between the sensor unit and the parked vehicle. This information provides a more precise determination of the vacancy of a parking space. The system will then be able to determine the vacancy even when a vehicle smaller than normal is parked.

[0022] Advantageously, the distance information may further be used to determine the distance between two parked vehicles and further define whether the empty space between the two vehicles corresponds to a parking space or a non-usable empty space, because for example one or more vehicles have been wrongly parked. This feature is particularly useful when the system is used in outdoor parking lots or in streets where the parking spaces are not explicitly marked with lines on the floor. In that case, vehicles may be parked with random spaces, and some spaces may give the deceptive impression that they are wide enough for parking a vehicle. The invention may also help the user to decide before hand whether the empty space may qualify as a parking space with regard to the size of his/her own vehicle. The resulting map of empty and occupied parking spaces may thus be generated by the actual available spaces between already parked vehicles.

[0023] In preferred embodiments of the invention, the sensor unit is mounted above a vehicle standard height. This preferred location of the sensor unit is well suited for sensing a plurality of vehicles. The location of the sensing unit above the vehicles is advantageous to avoid a vehicle or an object to be positioned too close to the sensor unit resulting in the masking of a sensing area and to the deficiency of the corresponding sensing measurement.

[0024] The mounting height of the sensor unit may be for example, the height of the ceiling of an indoor parking lot, around 2,5 m, or the height of a standard street light pole, depending on the environment. The flexibility of the mounting location is also an aesthetic advantage, as the sensor unit may be mounted in common with an existing light installation.

[0025] In embodiments of the invention, the phased array radar comprises at least one antenna face defining an antenna plane tilted with regard to the horizontal plane.

[0026] The antenna face of a phased array radar is commonly a square or rectangular plane face. Its orientation defines the maximal area that may be covered by the radar. When mounted above the height of a parked vehicle, the sense direction of the sensor unit is roughly vertical, corresponding to a horizontal plane of the antenna face of the phased array radar.

[0027] According to these embodiments of the invention, the mounting plane of the antenna is tilted with regard to the horizontal plane. Tilting the antenna face makes it possible for the phased array radar to scan in horizontal directions over the parking spaces. Accordingly, the sensor unit does not need to be located vertically above the scanned parking spaces area, but may be mounted for example in an alley between two rows of parking spaces or on a wall in front of a row of park spaces. These embodiments create more flexibility in the mounting location of the sensor unit.

[0028] In embodiments of the invention, the phased array radar comprises at least two complementary antenna faces mounted to sense different space areas.

[0029] These embodiments provide a wider scanning area for the radar. Advantageously, the antenna faces are oriented in directions that allow them to scan an area that is not overlapping with the scanning areas of the other antenna face. The antenna faces may have an orientation that is predetermined to adapt the scanned area to the particular configuration of the parking lot. For example the antenna faces may be oriented in symmetrically opposed directions with regard to a vertical plane when the sensor unit is mounted in an alley in between two rows of parking spaces.

[0030] More than two antenna faces may be used in order to cover an even wider scanning area if it is deemed necessary according to the configuration of the parking lot.

[0031 ] In preferred embodiments the parking monitoring system further comprises a control and evaluation unit configured to gather all the occupancy related status information from the sensor unit and create a map of vacant and occupied parking spaces. The map may then be shown as visual information for the driver to quickly spot a suitable vacant parking space and drive directly to it.

[0032] Advantageously, the control and evaluation unit is connected to a display configured to show the map of vacant and occupied parking spaces. The display may be visible by the driver from inside his/her vehicle and, for example installed at key locations of the parking lot, like the entry. These embodiments further enhance the communication between the system and vehicle drivers.

[0033] In embodiments, the system is further configured to wirelessly send information to an external device. The wireless external device may be a smartphone or a device located inside the vehicle which is able to inform directly a driver of the occupancy of the parking spaces. The information is consequently easily accessible for drivers. [0034] According to another aspect, the invention provides a method for monitoring a location of vacant and occupied parking spaces in a parking lot comprising a plurality of parking spaces aligned in rows, the parking lot being equipped with a parking space monitoring system comprising at least one sensor unit for sensing an occupancy related status of a plurality of parking spaces, the sensor unit comprising a phased array radar configured to scan a plurality of parking spaces and retrieve the occupancy related status, for each scanned parking space, the method comprising the steps of: a. scanning a plurality of parking spaces in the direction of the rows of parking spaces using the phased array radar; b. determining for each scanned parking space, an occupancy related status comprising a status between occupied and vacant;

[0035] The invention provides a method for monitoring a plurality of parking spaces with one sensor unit which has a low installation cost and is flexible as exposed above.

[0036] In embodiments, the method according to the invention further comprises the steps of: c. for each parking space with a vacant status determined in step b, scanning a plurality of parking spaces in the direction perpendicular to the rows of parking spaces using the phased array radar; d. determining for each parking space scanned in step c, an occupancy related status comprising a status between occupied and vacant; e. updating the occupancy status of the parking spaces determined in step d to obtain a final occupancy related status.

[0037] These embodiments provide further steps to increase the robustness and the precision of the monitoring method according to the invention.

[0038] In embodiments of the method according to the invention, the parking space monitoring system further comprises a control and evaluation system. The method further comprises the steps of: f. gathering the occupancy related status information from the sensor unit after each scan, using the control and evaluation system; and g. creating a map of vacant and occupied parking spaces using the control and evaluation system.

[0039] In embodiments of the method according to the invention, the parking space monitoring system also comprises a display. The method further comprises the step of: h. displaying the map of vacant and occupied parking spaces using the display.

[0040] In these embodiments, the method according to the invention provides a further treatment of the information from the sensor in a form of a map. The map information is communicated to a driver in a readable graphic way and helps the driver to quickly understand and use the information from the sensors.

Brief Description of the Drawings

[0041 ] Further details and advantages of the present invention will be apparent from the following detailed description of not limiting embodiments with reference to the attached drawing, wherein:

Fig.1 is a schematic perspective view of a parking lot comprising a parking space monitoring system according to preferred embodiments of the invention.

Fig.2 is a schematic side view of the parking space monitoring system of

Fig. 1 .

Fig.3 is a schematic representation of the parking space monitoring system of

Fig. 1 .

Description of Preferred Embodiments

[0042] Fig. 1 schematically illustrates one embodiment of a parking space monitoring system 10 according to the invention. In this embodiment, the system is mounted in an indoor parking lot comprising a plurality of parking spaces 12, which are either occupied or vacant. The parking spaces 12 are marked by lines 14 drawn on the floor 16 of the parking lot.

[0043] As shown in Fig. 1 and 2, the parking space monitoring system 10 comprises a sensor unit 18 installed on a ceiling 20 of an indoor parking lot in the middle of an alley 22 between two rows of parking spaces 12. [0044] The sensor unit 18 comprises a phased array radar 24 configured to scan a plurality of parking spaces 12 and retrieve an occupancy related status for each scanned parking space 12.

[0045] The occupancy related status may be any information useful to help the user to decide to park his/her vehicle in the respective parking space. Here the occupancy related status comprises the occupancy, and the location of the scanned parking space 12. The occupancy is the information whether a vehicle 25 is already occupying the parking space 12, and the location is the location of the scanned parking space 12 relative to the sensor unit 18.

[0046] In embodiments, not shown, the phased array radar is a pulsed radar or a frequency modulation continuous wave (FMCW) radar. In these embodiments, the occupancy related status may further comprise the distance between the sensor unit and a parked vehicle.

[0047] The number of parking spaces 12 that may be scanned by the phased array radar 24 depends on the location of the phased array radar 24. A farther radar will be able to scan over a larger area and consequently over a bigger number of parking spaces, with the drawback that it will lose in resolution or require a more powerful scanning beam. In the example as shown in Fig. 1 , the location of the phased array radar 24 is defined by the height of the parking lot ceiling 20, and the radar 24 is able to scan e.g. five adjacent parking spaces 12 in one row.

[0048] Although in the embodiment of Fig. 1 only one sensor unit 18 is described, it is understood that the parking space monitoring system 10 according to the invention may comprise more than one sensor unit 18. The number of sensor units 18 will e.g. correspond to the total number of parking spaces 12 to monitor in the parking lot divided by the number of parking spaces 12 that can be scanned by one single radar 24.

[0049] Scanning is realized by transmitting, and steering a radio frequency signal formed as a beam 26 over the parking spaces 12. In order to transmit the radio frequency signal, the phased array radar 24 further comprises a plurality of antennas, not shown, which are grouped together into a first antenna face 28, and a second antenna face 30. The antenna faces 28, 30, define respectively a square or rectangular plane on which a predetermined number of radio frequency antennas are mounted. It is common knowledge in the art that for a wave length λ, the distance between two radio frequency antennas should not exceed λ/2 in order to remove interference, which limits the number of radio frequency antennas arranged in a given surface.

[0050] In order to steer the beam 26 of the radar 24, each antenna of the antenna faces 28, 30, transmits a signal with a predetermined phase delay. The scanning principle of the phased array radar will not be exposed in the following description as it is commonly known in the art. Any suitable beam steering method may be used in the context of the invention.

[0051 ] The first and the second antenna faces 28, 30 are oriented towards rows of parking spaces 12 to monitor, and in different directions so that the first antenna face 28 scans a first row of parking spaces 12 while the second antenna face 30 scans a second row of parking spaces 12. The resulting orientation of the antenna faces 28, 30 is facing down from the ceiling 20, and parallel to the row of parking spaces 12. The first and second antenna faces 28, 30, are tilted of an angle a with regard to a horizontal plane substantially parallel to the floor 16 of the parking spaces. It results that as we see in Fig. 2, the first and second antenna faces 28, 30 are installed symmetrically with regard to a vertical plane S going through the middle of the parking alley 22.

[0052] In other embodiments, not shown, the first and second antenna faces have different tilted angles, and are not symmetrically oriented. This allows the system to scan parking lots with specific configurations of the parking spaces.

[0053] In order to remove errors showing a wrongly determined vacant space caused when a parking space is occupied by a small car, it is preferable for the sensor unit 18 to scan an area that goes deep enough inside the parking space and not only the area close to the end marking line.

[0054] Accordingly, for given dimensions of the antenna faces 28, 30, the tilted angle a and the mounting height H of the antenna faces 28, 30 may be adjusted in order to obtain an optimized scanning area corresponding to the configuration of the parking lot. [0055] Fig. 2, further shows that the width W of the area that is scanned by the sensor unit 18 depends on both the distance H between the sensor unit 18 and the floor 16 of the parking spaces 12, and the tilted angle a of the antenna faces 28, 30. The preferred value of the angle a depends on the distance between the sensor unit 18 and the parking spaces 12.

[0056] Advantageously, in order to create the widest scanned parking space area, the antenna plane is tilted with regard to the horizontal plane. A typical angle for the application of parking spot surveillance in parking garages would e.g. be 17 degrees for a mounting height H = 2.5m, resulting in a maximal surveilled area of 16 meters (e.g. 6 m parking spot length + 4 m driving lane width). Other mounting heights may require different angles, also depending on the area that shall be surveilled. In theory, any angle and mounting height is imaginable.

[0057] During the scanning of the parking spaces 12, the radar 24 first proceeds to a scan symmetrically with both antenna faces 28, 30 at the same time. A first scan is realized along a line parallel to the row of parking spaces, indicated by the axis y shown in Fig. 1 . The scan is performed at a predetermined depth value inside the parking spaces which correspond to a constant value along the axis x shown in Fig. 1 .

[0058] As there are various length sizes for a vehicle, a parked vehicle would not occupy the same length inside a parking space. For example, if a vehicle is parked such that it is completely driven forward in a parking space away from the alley, there is a risk that the space between the alley and the parked vehicle comprises the space scanned by the radar. The radar would therefore wrongly sense a vacant parking space. The depth value of the first scan is hence preferably predetermined in order to correspond to a distance from the edge of the parking space boarding the alley, where a standard length vehicle parked as described above would still be sensed by the sensor unit.

[0059] Once the first scan is performed, a first status of occupancy is generated with regard to the location of each scanned parking space. For each parking space that has been deemed vacant, the system performs a second scan in the direction of the depth of the parking spaces, indicated by axis x in Fig. 1 . The second scan allows refining the occupancy status of the parking space by checking farther inside whether a vehicle of a length smaller than the standard length is parked. After the second scan, the occupancy status of the former vacant spaces is updated to output the final occupancy status.

[0060] As shown in Fig. 3, the sensor unit 18 is further connected to a control and evaluation unit 32 by a connection means 34. The connection means 34 may comprise, for example an electrical cable or a wireless communication link.

[0061 ] The control and evaluation unit 32 receives the occupancy related status from the sensor unit 18 in real-time after each scan. The control and evaluation unit 32 further computes the received information after each scan in order to create a map of the vacant and occupied parking spaces 12.

[0062] The control and evaluation unit 32 further comprises a display 36 that is visible by the drivers. For example, a display may be installed at the entry of a parking lot's storey or before each parking spaces row. The display 36 shows a map of all the parking spaces and indicates which one is vacant and which one is occupied.

[0063] In case there are more than one sensor unit, the control and evaluation unit gathers all the occupancy related statuses of all the sensor units. The location information for each parking space is then associated with the location of its respective scanning sensor unit before further computation.

[0064] In embodiments of the invention, not shown, compared to the embodiments as shown in Fig. 2, the occupancy related status information may be sent from the control and evaluation unit or directly from the sensor unit to a device in the user vehicle, for example a smartphone, the information is further treated by a dedicated application that is able to create a map of the vacant and occupied parking spaces in real-time.

[0065] In other embodiments of the invention not shown, the sensor unit only comprises one antenna face. These embodiments are to combine with a higher mounting height of the sensor unit in order to increase the scanning area of the sensor. When compared to the previously described system comprising two antenna faces, the resulting sensor unit requires less components and allows a reduction of the system's fabrication cost. Due to the higher mounting height, these embodiments are better suited for outdoor parking lots. [0066] In alternative embodiments not shown, the sensor unit comprises four antenna faces facing in four different directions in order to cover 360 degrees of azimuth angle around the sensor unit. These systems are capable of monitoring any configuration of parking spaces with a greater precision and robustness.

List of Reference Symbols

10 parking space monitoring system

12 parking space

14 lines

16 floor

18 sensor unit

20 ceiling

22 alley

24 phased array radar

25 vehicle

26 beam

28 first antenna face

30 second antenna face

32 control and evaluation unit

34 connection means

36 display

Claims

1 . Parking space monitoring system comprising: at least one sensor unit for sensing an occupancy related status of a plurality of parking spaces, characterized in that the sensor unit comprises a phased array radar configured to scan a plurality of parking spaces and retrieve the occupancy related status for each scanned parking space.

2. Parking space monitoring system according to claim 1 , wherein the occupancy related status comprises occupancy and location of each scanned parking space.

3. Parking space monitoring system according to claim 1 , wherein the occupancy related status comprises the distance to the parked vehicle.

4. Parking space monitoring system according to any one of the preceding claims, wherein the sensor unit is mounted above a vehicle standard height.

5. Parking space monitoring system according to any one of the preceding claims, wherein the phased array radar comprises at least one antenna face defining an antenna plane tilted with regard to the horizontal plane.

6. Parking space monitoring system according to any one of the preceding claims, wherein the phased array radar comprises at least two complementary antenna faces mounted to sense different space areas.

7. Parking space monitoring system according to any one of the preceding claims, further comprising a control and evaluation unit configured to gather the occupancy related status information from the sensor unit and create a map of vacant and occupied parking spaces.

8. Parking space monitoring system according to claim 7, further comprising a display configured to show the map of vacant and occupied parking spaces.

9. Parking space monitoring system according to any one of claims 1 to 7, further configured to wirelessly send information to an external device.

10. Method for monitoring a location of vacant and occupied parking spaces in a parking lot comprising a plurality of parking spaces aligned in rows, the parking lot being equipped with a parking space monitoring system comprising at least one sensor unit for sensing an occupancy related status of a plurality of parking spaces, the sensor unit comprising a phased array radar configured to scan a plurality of parking spaces and retrieve the occupancy related status, between vacant and occupied, for each scanned parking space, the method comprising the steps of: a. scanning a plurality of parking spaces in the direction of the rows of parking spaces using the phased array radar; b. determining for each scanned parking space, an occupancy related status comprising a status between occupied and vacant.

1 1 . Method for monitoring a location of vacant and occupied parking spaces in a parking lot according to claim 10, the method further comprising the steps of: c. for each parking space with a vacant status determined in step b, scanning a plurality of parking spaces in the direction perpendicular to the rows of parking spaces using the phased array radar; d. determining for each parking space scanned in step c, an occupancy related status comprising a status between occupied and vacant; e. updating the occupancy status of the parking spaces determined in step d to obtain a final occupancy related status.

12. Method for monitoring a location of vacant and occupied parking spaces in a parking lot according to claim 10 or 1 1 , the parking space monitoring system further comprising a control and evaluation system, the method further comprising the steps of: f. gathering the occupancy related status information from the sensor unit after each scan, using the control and evaluation system; and g. creating a map of vacant and occupied parking spaces using the control and evaluation system;

13. Method for monitoring a location of vacant and occupied parking spaces in a parking lot according to claim 12, the parking space monitoring system further comprising a display, the method further comprising the step of: displaying the map of vacant and occupied parking spaces using the display.