TRAFFIC SITUATION MONITORING SYSTEM

Description

[0001] The invention relates to a system for monitoring a traffic situation.

[0002] Radar development in the mobility sector has increased significantly and steadily in recent years. Radar systems are necessary for both self-driving cars and self-driving trains to reliably detect obstacles. Thanks to ETSI's frequency spectrum allocation up to 70 GHz, radar sensors can now be built very small.

[0003] Car manufacturers and industry primarily use radar sensors for object detection at distances of 0 to 300 meters and for speed measurement. The sensors currently available on the market act as pure sensors, meaning they detect their surroundings based on emitted radar waves. The reflected signal at the radar receiver changes continuously and depends on the surface of the target and the measurement location.

[0004] Based on the radar signals reflected from objects within a sensor unit's monitoring area and received by the respective sensor unit, the current traffic situation in the sensor unit's monitoring area can be determined, which is required to control an autonomous vehicle. Especially when sensor units are used to control autonomous vehicles, knowledge of the functionality of the sensor units used is essential.

[0005] WO 95 / 20172 A1 discloses a system comprising a vehicle-mounted radar system for transmitting radar signals and receiving radar signals reflected by a target, and a trackside transponder capable of communicating with the vehicle-mounted radar system. The transponder is installed at a fixed location along a roadway and is capable of receiving radar signals from the vehicle-mounted radar system, which comprise interrogation messages to the trackside transponder. The transponder transmits preprogrammed messages back to the vehicle-mounted radar system.

[0006] German Patent Application DE 10 2016 221 440 A1 discloses a method for diagnosing a sensor system installed in a vehicle for detecting objects in the vehicle's surroundings. Data characterizing a reference object is transmitted to the vehicle via an ITS communication system. Expected detection data for the reference object is calculated in the vehicle based on the transmitted data. The expected detection data is compared with actual detection data obtained when the sensor system detects the reference object.

[0007] For reliable monitoring of traffic safety, it is essential to be able to continuously determine the functional status of the sensor unit used in order to identify any faulty sensor units.

[0008] The object of the present invention is to provide a system for monitoring a traffic situation that enables reliable identification of faulty sensor units.

[0009] This problem is solved by the system of independent claims. Further developments are specified in the dependent patent claims.

[0010] According to one aspect of the invention, a system for monitoring a traffic situation is provided, comprising: at least one radar sensor unit for recording environmental data of a monitoring area of ​​the radar sensor unit, wherein the radar sensor unit is configured to emit radar signals in the direction of the monitoring area, to receive radar signals reflected from objects within the monitoring area to the radar sensor unit, and to generate environmental data of the monitoring area on the basis of the received radar signals; a processor unit for evaluating the environmental data of the radar sensor unit and for determining the traffic situation within the monitoring area based on the environmental data of the radar sensor unit; and a reference signal unit for outputting a reference signal to the radar sensor unit, characterized in that the reference signal unit is configured to provide a radar signal emitted by the radar sensor unit with a modulation and to reflect the modulated radar signal back to the radar sensor unit as a reference signal, and in that the processor unit is configured to identify the modulated radar signal as a reference signal of the reference signal unit and to detect a malfunction of the radar sensor unit if no reference signal is received by the radar sensor unit.

[0011] This achieves the technical advantage of providing a system for monitoring a traffic situation that is suitable for verifying the functionality of a radar sensor unit during operation. Using the reference signal unit, a reference signal can be sent to the radar sensor unit, which can be detected by the radar sensor unit and interpreted by the processor unit. If such a reference signal is not detected by the radar sensor unit, the processor unit can identify a malfunction of the respective radar sensor unit and, if necessary, interpret the monitoring of the traffic situation as faulty and terminate it.

[0012] The reference signal unit is configured to reflect the radar signals emitted by the radar sensor unit for monitoring the surveillance area of ​​the radar sensor unit and to send them back to the radar sensor unit. During the reflection process of the radar signals by the reference signal unit, the reference signal unit imparts an individual modulation to the reflected radar signals, allowing the processor unit to identify the reflected radar signals as a reference signal from the reference signal unit. This further provides the technical advantage that no separate transmission unit is required for the reference signal unit to transmit the reference signal. The reference signals from the reference signal unit are based exclusively on the radar signals emitted by the radar sensor unit.

[0013] For the purposes of the application, radar signals are signals of electromagnetic radiation in the frequency range between 60 GHz and 120 GHz, which is typical for radar applications.

[0014] For the purposes of the application, a traffic situation is a situation in road or rail traffic. A traffic situation can include a traffic volume of vehicles, especially cars, trucks, motorcycles, bicycles, or pedestrians, or rail vehicles. A traffic situation can also include the absence of any road users.

[0015] According to the invention, the reference signal unit has a first reflection state and a second reflection state, and wherein a radar signal reflected by the reference signal unit in the first reflection state differs in at least one property from a radar signal reflected by the reference signal unit in the second reflection state, and wherein the reference signal unit can be switched alternately between the first reflection state and the second reflection state at a switching frequency.

[0016] This achieves the technical advantage that when the radar signals from the radar sensor unit are reflected by the reference signal unit, a modulation can be impressed on the reflected radar signals, so that radar signals reflected at the reference signal unit with an impressed modulation can be generated as reference signals. By alternatingly connecting the reference signal unit between the first and second reflection states, a reference signal can be generated that comprises alternating signal sections that each differ from one another in at least one property. This property can be, for example, an amplitude of the reflected radar signals, so that by alternating between the two reflection states, an amplitude-modulated or phase-modulated reflected radar signal can be generated as a reference signal.

[0017] According to one embodiment, the reference signal unit has a first reflection surface which is configured to reflect radar signals of the radar sensor unit, wherein in the first reflection state the reflection surface is brought into a reflection position in which a reflection of the radar signals of the radar sensor unit is enabled, and wherein in the second reflection state the reflection surface is brought into a non-reflection position in which a reflection of the radar signals of the radar sensor unit is prevented.

[0018] This provides the technical advantage of providing a simple solution for generating the reference signal as a modulated reflected radar signal. By alternating the first reflection surface between a reflection position, in which reflection of the radar signals from the radar sensor unit is possible, and a non-reflection position, in which no reflection of the radar signals occurs, an amplitude-modulated reflected radar signal can be generated as a reference signal. This allows for the simplest possible implementation of the modulated reference signal.

[0019] Alternatively, the reflection surfaces can be realized by equivalent antenna elements, wherein for switching the reflection surfaces between non-reflection position and reflection position, the antenna elements can be electronically controllably switched alternately into a non-reflecting state and / or into a reflecting state.

[0020] According to one embodiment, the reference signal unit further comprises a second reflection surface, wherein the second reflection surface is configured to reflect radar signals of the radar sensor unit, and wherein in the second reflection state, the second reflection surface is brought into a reflection position in which a reflection of the radar signals of the radar sensor unit by the second reflector unit is enabled.

[0021] This provides the technical advantage of providing another simple solution for generating the modulated reference signal. By alternately placing the first and second reflection surfaces in the reflection position, a modulated reflected radar signal can be generated.

[0022] According to one embodiment, the first reflection surface and the second reflection surface are arranged at different distances from the radar sensor unit.

[0023] This achieves the technical advantage of providing a further simple solution for generating the modulated reference signal. By spacing the two reflection surfaces apart from one another in the direction of the radar sensor unit, the radar signals reflected by the first reflection surface and the radar signals reflected by the second reflection surface travel different distances from the time they are transmitted by the radar sensor unit to the time they are received by the radar sensor unit. By alternately connecting the first and second reflection surfaces to corresponding reflection positions, a modulated reflected radar signal can be generated with alternately arranged signal sections traveling different distances.

[0024] According to one embodiment, the reference signal unit comprises a first antenna array and / or a second antenna array, wherein the antenna array and / or second antenna array is configured to reflect radar signals of the radar sensor unit, and wherein the first reflection surface and / or the second reflection surface is formed by the first antenna array and / or the second antenna array.

[0025] This achieves the technical advantage that a further simple solution for generating the modulated reference signal can be provided. Because the first reflection surface and / or the second reflection surface is formed by a first antenna array and / or a second antenna array, the reference signal unit can be electrically connected between the first reflection state and the second reflection state. By alternately switching the first antenna array and / or the second antenna array on and off, whereby in the switched-on state the respective antenna array can reflect a received radar signal back to the radar sensor unit, whereas in the switched-off state reflection of the radar signal is not possible, a modulated reflected radar signal can be generated. By means of the electrical connection orBy electrically switching the two antenna arrays on and off, any switching frequency of the reference signal unit and, associated with it, any modulation frequency of the reference signal can be achieved.

[0026] According to one embodiment, the reference signal unit comprises a reflector body with at least one body surface, wherein a reflection layer is applied to the at least one body surface, wherein the

[0027] Reflection layer is configured to reflect radar signal, and wherein the first reflection surface and / or the second reflection surface is formed by the reflection layer applied to the at least one body surface.

[0028] This achieves the technical advantage of providing a further simple solution for generating the modulated reference signal. For this purpose, the reference signal unit comprises a reflector body with at least one body surface on which a reflective layer is applied, which is configured to reflect radar signals. By alternately placing the reflective layer in a reflective position, in which reflection of the radar signals from the radar sensor unit is enabled, while in a non-reflective position of the reflective layer, reflection of the radar signals is not enabled, an amplitude-modulated reflected radar signal can be generated.

[0029] According to one embodiment, the radar sensor unit is stationary positioned on a road section or rail section to be monitored, and wherein the reference signal unit is stationary positioned in the monitoring area of ​​the radar sensor unit.

[0030] This provides the technical advantage of allowing a stationary traffic situation to be monitored. By positioning the radar sensor unit at a fixed location on a road or rail section to be monitored, traffic situations on this selected road or rail section can be monitored.

[0031] By positioning the reference signal unit in a fixed location within the radar sensor unit's monitoring range, it can be ensured that if the radar sensor unit fails to detect a reference signal from the reference signal unit, a malfunction of the radar sensor unit can be determined. This allows for the provision of a reliable, fixed system for monitoring a traffic situation.

[0032] According to one embodiment, the system further comprises a further radar sensor unit for recording environmental data of a further monitoring area of ​​the further radar sensor unit, wherein the further radar sensor unit is configured to emit further radar signals in the direction of the further monitoring area, to receive radar signals reflected from objects within the further monitoring area to the further radar sensor unit and to generate further environmental data of the further monitoring area on the basis of the received further radar signals;a further processor unit for evaluating the further environmental data of the further radar sensor unit and for determining the traffic situation within the further monitoring area on the basis of the further environmental data of the further radar sensor unit, wherein the reference signal unit is configured to provide further radar signals emitted by the further radar sensor unit with the modulation and to reflect a further modulated radar signal back to the further radar sensor unit as a further reference signal, wherein the further processor unit is configured to identify the further modulated radar signal as a further reference signal of the reference signal unit and to detect a malfunction of the further radar sensor unit if no further reference signal is received by the further radar sensor unit, and wherein the further radar sensor unit is arranged on an autonomously driving vehicle;

[0033] This provides the technical advantage of providing a system for monitoring a traffic situation in which the functionality of several radar sensor units can be checked using the reference signal unit. The additional radar sensor unit, which can be installed in an autonomously driving vehicle, for example, can generate additional reference signals as reflected radar signals from the additional radar sensor unit. The additional processor unit, which is configured to evaluate the environmental data of the additional radar sensor unit and determine a corresponding traffic situation, can determine the functionality of the additional radar sensor unit based on the detected additional reference signals. This can expand the range of applications of the system for monitoring a traffic situation.

[0034] According to one embodiment, the switching frequency is between 60 GHz and 85 GHz.

[0035] This achieves the technical advantage of modulating the reference signals and other reference signals with a frequency that is within the range of a commercially available radar sensor unit and can therefore be detected by it.

[0036] The above-described properties, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood through the explanations of the following, highly simplified, schematic representations of preferred embodiments. In each case, FIG 1 a schematic representation of a system for monitoring a traffic situation according to one embodiment; FIG 2 a further schematic representation of the system for monitoring a traffic situation according to a further embodiment; FIG 3 a further schematic representation of the system for monitoring a traffic situation according to a further embodiment; FIG 4 a further schematic representation of the system for monitoring a traffic situation according to a further embodiment; FIG 5 a schematic representation of a reference signal unit of the system for monitoring a traffic situation according to an embodiment; FIG 6 a schematic representation of the reference signal unit of the system for monitoring a traffic situation from Fig. 5 in another state; FIG 7 a further schematic representation of the reference signal unit of the system for monitoring a traffic situation according to a further embodiment; FIG 8 a further schematic representation of the reference signal unit of the system for monitoring a traffic situation according to a further embodiment; FIG 9 a schematic representation of the reference signal unit of the system for monitoring a traffic situation in Fig. 8 in another state; and FIG 10 a schematic representation of the reference signal unit of the system for monitoring a traffic situation in Fig. 8 in another state.

[0037] FIG 1 shows a schematic representation of a system 100 for monitoring a traffic situation according to one embodiment.

[0038] In the embodiment in FIG 1 Both the radar sensor unit 101 and the reference signal unit 109 of the system 100 for monitoring a traffic situation are arranged in a fixed location on a road section 113. In the FIG 1 In the embodiment shown, the road section 113 is designed as a road intersection.

[0039] The radar sensor unit 101 comprises a monitoring area 103. The monitoring area 103 defines an area that the radar sensor unit 101 can monitor by emitting radar signals 105 and detecting reflected radar signals.

[0040] In the embodiment in FIG 1 the reference signal unit 109 is arranged within the monitoring area 103 of the radar sensor unit 101.

[0041] The radar sensor unit 101 is further connected to a processor unit 107.

[0042] Furthermore, an object 108 is arranged in the monitoring area 103 of the radar sensor unit 101. The object 108 can be, for example, a road user or another detectable object.

[0043] To determine the traffic situation within the monitoring area 103, the radar sensor unit 101 transmits radar signals 105. The transmitted radar signals 105 strike the object 108 and are reflected by the object 108 as reflected radar signals 106 back to the radar sensor unit 101, which detects the reflected radar signals 106. Based on the detected reflected radar signals 106, the radar sensor unit 101 generates environmental data of the objects within the monitoring area 103. Based on this environmental data of the radar sensor unit 101, the processor unit 107 determines a traffic situation within the monitoring area 103. For the sake of clarity of the illustration, FIG 1 Only radar signals 105 are shown, which, on the one hand, impinge on the object 108 and, on the other hand, illuminate the reference signal unit 109. To determine the traffic situation within the surveillance area 103, additional radar signals 105 would be emitted, illuminating the entire surveillance area 103.

[0044] During the transmission of radar signals 105 by radar sensor unit 101 to determine the traffic situation within surveillance area 103, radar signals 105 are reflected back to radar sensor unit 101 by reference signal unit 109 as reference signal 111 in the form of modulated reflected radar signals. By modulating reference signal 111, which is applied to radar signals 105 by reference signal unit 109 during the reflection process, processor unit 107 can identify reference signal 111 detected by radar sensor unit 101 as a reference signal of reference signal unit 109.

[0045] In the event that the radar sensor unit 101 detects the reference signal 111 of the reference signal unit 109, the processor unit 107 determines the functional state of the radar sensor unit as functional and a malfunction of the radar sensor unit 101 can be ruled out.

[0046] In the event that the radar sensor unit 101 does not detect a reference signal from the reference signal unit 109, the processor unit 107 determines a malfunction of the radar sensor unit 101 and monitoring of the traffic situation within the monitoring area 103 is determined to be faulty and, if necessary, interrupted.

[0047] In the embodiment in FIG 1 The reference signal unit 109 is designed exclusively as a reflector. An additional transmitting unit for transmitting the reference signal 111 is not provided in the reference signal unit 109. The transmitted reference signals 111 are based exclusively on the transmitted radar signals 105 of the radar sensor unit 101.

[0048] The radar sensor unit 101 can be any commercially available radar sensor. The emitted radar signals 105 can be arranged in a frequency range typical for radar signals.

[0049] The modulation of the reference signals 111 is achieved by the reference signal unit 109 by alternating the reference signal unit 109 between a first reflection state and a second reflection state. The radar signals reflected by the reference signal unit 109 in the first and second reference states differ in at least one property. For example, the first reflection state can be realized by enabling reflection of the radar signals 105 by the reference signal unit 109, while in the second reflection state, no reflection occurs at the reference signal unit 109.

[0050] Alternatively to the FIG 1 In the embodiment shown, the system 100 can comprise a plurality of radar sensor units 101, for example, to view a larger monitoring area or to enable more precise monitoring of a narrow road section. Furthermore, the system 100 can comprise a plurality of reference signal units 109, each configured to transmit corresponding reference signals to the plurality of radar sensor units 101.

[0051] FIG 2 shows a further schematic representation of the system 100 for monitoring a traffic situation according to another embodiment.

[0052] Deviating from the embodiment in FIG 1 is in the embodiment in FIG 2 The radar sensor unit 101 is arranged in a vehicle 115, in particular an autonomously driving vehicle 115. The processor unit 107 is also arranged in the vehicle 115. The reference signal unit 109, however, is arranged stationary on a road section 113.

[0053] In particular, the reference signal unit 109 is arranged on a traffic light system 117. Alternatively, the reference signal unit 109 can be arranged at any location on the road section 113 to be monitored.

[0054] Analogous to FIG 1 The radar sensor unit 101 transmits radar signals 105 to monitor the traffic situation within the monitoring area 103, detects radar signals reflected from corresponding objects within the monitoring area 103, generates environmental data based on the detected radar signals, which are evaluated by the processor unit 107 and a traffic situation is determined based on the environmental data. To avoid unnecessary repetition, these processes are FIG 2 not shown.

[0055] Radar signals 105 emitted by radar sensor unit 101 are reflected by reference signal unit 109, and a reference signal 111 in the form of a modulated reflected radar signal is sent back to radar sensor unit 101. Based on this reference signal 111, processor unit 107 determines the functional state of radar sensor unit 101 by determining the radar sensor unit as faulty in the absence of a corresponding reference signal.

[0056] FIG 3 shows a further schematic representation of the system 100 for monitoring a traffic situation according to another embodiment.

[0057] The embodiment in FIG 3 differs from the embodiment in FIG 2 merely in that the radar sensor unit 101 and the processor unit 107 are arranged in an autonomously driving rail vehicle 119, which is moved on a rail section 121.

[0058] FIG 4 shows a further schematic representation of the system 100 for monitoring a traffic situation according to another embodiment;

[0059] The FIG 4 The embodiment shown is based on the embodiment in FIG 1 In addition to the FIG 1 The system 100 in the embodiment shown in FIG 4 a further radar sensor unit 123 and a further processor unit 131, each arranged in an autonomously driving vehicle 115. The further radar sensor unit 123 is designed to determine a traffic situation within a further monitoring area 125. To this end, the further radar sensor unit 123 emits further radar signals 127, which are reflected by objects within the further monitoring area 125 and detected by the further radar sensor unit 123. Based on the detected further radar signals 127, the further radar sensor unit 123 creates environmental data, on the basis of which the further processor unit 131 determines a traffic situation within the further monitoring area 125.

[0060] A detection of objects within the monitoring area 103 or the further monitoring area 125 by the radar sensor unit 101 or the further radar sensor unit 123 is due to the clarity of the FIG 4 not shown.

[0061] Further radar signals 127 emitted by the further radar sensor unit 123 are reflected by the reference signal unit 109, which is arranged within the further monitoring area 125, and further reference signals 129 in the form of modulated, reflected further radar signals are transmitted from the reference signal unit 109 to the further radar sensor unit 123. Based on the further reference signals 129 detected by the further radar sensor unit 123, the further processor unit 131 determines the functional state of the further radar sensor unit 123 by determining a malfunction of the further radar sensor unit 123 if a further reference signal 129 is not detected by the further radar sensor unit 123.

[0062] By modulating the further reference signals 129, these further reference signals 129 can be clearly identified by the further processor unit 131 as reference signals of the reference signal unit 109. For this purpose, the system 100 in the embodiment in FIG 4 a radio transmission unit 133 connected to the processor unit 107. Information is transmitted via the radio transmission unit 133 to the processor unit 131 by transmitting corresponding radio signals 135, on the basis of which the further processor unit 131 can identify the modulation of the further reference signals 129.

[0063] In practice, an autonomously driving vehicle 115 could thus drive in the transmission range of the radio transmission unit 133 and receive from it, by means of transmission via the transmission of the radio signals 135, the information required to decode the reference signals of the reference signal unit 109 in order to thus clearly identify the reference signals of the reference signal unit 109 as reference signals.

[0064] After transmission of the decoding function by the radio transmission unit 133 to the further processor unit 131 of the autonomously driving vehicle 115, as soon as the road section 113 in which the reference signal unit 109 is arranged enters the further monitoring area 125, the latter could receive the further reference signals 129 via the further radar sensor unit 123 and clearly identify them as reference signals on the basis of the transmitted decoding information.

[0065] It can thus be achieved that any autonomously driving vehicles that reach the road section monitored by the system 100 are provided with the necessary information by means of which the any autonomously driving vehicles can decode the reference signals of the reference signal unit or the plurality of reference signal units of the system 100 and thus identify them as reference signals.

[0066] Thus, the system 100 can check the functionality of the radar sensor units of any autonomously driving vehicle using the reference signals emitted by the reference signal unit 109.

[0067] FIG 5 und FIG 6 show a schematic representation of a reference signal unit 109 of the system 100 for monitoring a traffic situation according to an embodiment in two states.

[0068] In the embodiment in FIG 5 und FIG 6 The radar sensor unit 101 comprises a radar logic unit 137 and a radar antenna array 139. Both components are components of commercially available radar sensors. Using the radar logic unit 137 and the radar antenna array 139, the radar sensor unit 101 is capable of transmitting radar signals 105.

[0069] Furthermore, FIG 5 und FIG 6 a first reflection surface 141 and a second reflection surface 143 of the reference signal unit 109 are shown. The first reflection surface 141 and the second reflection surface 143 are spaced apart from each other by a distance 145.

[0070] In FIG 5 the case is shown that the first reflection surface 141 is in a reflection position and radar signals 105 of the radar sensor unit 101 are reflected at the first reflection surface 141 of the reference signal unit 109.

[0071] In FIG 6 the case is shown that the first reflection surface 141 is arranged in a non-reflection position in which no reflection of the radar signals 105 occurs, while the second reflection surface 143 is arranged in a reflection position and a reflection of the radar signals 105 occurs at the second reflection surface 143.

[0072] Due to the distance 145 between the first reflection surface and the second reflection surface, there is a difference in the length of the path traveled between the radar signals reflected at the first reflection surface 141 and the radar signals reflected at the second reflection surface 143.

[0073] This path difference of the radar signals reflected at the different reflection surfaces can be detected by the radar sensor unit 101. Thus, by alternating switching between the FIG 5 shown condition and the one in FIG 6 In the state of the reference signal unit 109 shown, a modulated reference signal can be generated in which sections of radar signals reflected at the first reflection surface 141 and sections of radar signals reflected at the second reflection surface 143 alternate.

[0074] By connecting the FIG 5 shown first reflection state and the one in FIG 6 In the second reflection state of the reference signal unit 109 shown, an arbitrarily modulated reference signal with any modulation frequency can thus be generated.

[0075] Alternatively, any information can be impressed on the reference signal by appropriately connecting the two reflection states.

[0076] FIG 7 shows a further schematic representation of the reference signal unit 109 of the system 100 for monitoring a traffic situation according to a further embodiment.

[0077] In the embodiment in FIG 7 The first reflection surface 141 is realized by a first antenna array 151, and the second reflection surface 143 is realized by a second antenna array 149. The first antenna array 147 is connected to a control logic 153 via a radio-frequency switch 151. The second antenna array 149 is connected to the control logic 153 via another radio-frequency switch 152.

[0078] The two antenna arrays 147, 149 can be alternately switched on and off via the control logic 153 and the two high-frequency switches 151, 152. In an on state, the two antenna arrays 147, 149 are configured to reflect radar signals 105 from the radar sensor unit 101, while in a off state, the antenna arrays 147, 149 cannot reflect the radar signals 105.

[0079] The first antenna array 147 and the second antenna array 149 are in the embodiment in FIG 6 spaced apart by a distance of 145.

[0080] By alternately switching the first and second antenna arrays 147, 149 on and off, the FIG 5 shown first reflection state of the reference signal unit 109 and the one in FIG 6 The second reflection state of the reference signal unit 109 shown can be generated. By alternately switching the first and second antenna arrays 147, 149 on and off, an arbitrarily modulated reference signal 111 can thus be generated.

[0081] FIG 8, FIG 9 und FIG 10 show a further schematic representation of the reference signal unit 109 of the system 100 for monitoring a traffic situation according to a further embodiment in three states.

[0082] In the embodiment in FIG 8, FIG 9 und FIG 10 The reference signal unit 109 comprises a reflector body 155, which comprises at least one body surface 157, on which a reflection layer 159 is applied, which is configured to reflect radar signals. In the embodiment in FIG 8, FIG 9 und FIG 10 The reflector body 155 is designed as a cuboid-shaped body. Alternatively, the reflector body 155 can have any shape with a body surface 157.

[0083] In FIG 8 the case is shown that the body surface 157, in particular the reflection layer 159, is arranged in the reflection position and a reflection of the emitted radar signals 105 of the radar sensor unit 101 is reflected by the reflection layer 159.

[0084] In FIG 9 The case is shown in which the reflection layer 159 is rotated by 45° from the reflection position, so that a reduction in the reflectivity of the reflection layer 159 is produced. In FIG 9 the alignment of the radar sensor unit 101 and the reflector body 155 as well as the direction of emitted radar signals 105 is identical to that in FIG 8 shown. The one in FIG 9 The case shown differs from the one in FIG 8 merely by rotating the reflector body 155 by 45°.

[0085] In FIG 10 The case is shown in which the reflection layer 159 is rotated by 90° out of the reflection position, so that a reflection of the radar signals 105 by the reflector body 155 cannot occur. In FIG 10 the alignment of the radar sensor unit 101 and the reflector body 155 as well as the direction of the emitted radar signals 105 is identical to that in FIG 8 shown. The one in FIG 10 The case shown differs from the one in FIG 8 merely by rotating the reflector body 155 by 90°.

[0086] By placing the reflector body 155 between the FIG 8, FIG 9 und FIG 10 By interconnecting the reflected radar signals in the states shown, a modulation of the reflected radar signals and thus a modulated reference signal 111 can be generated. For this purpose, the reflector body 155 can be rotated, for example, at an arbitrarily selectable rotation speed about the rotation axis 161, so that the reflection layer 159 is brought into the reflection position at a corresponding frequency and an amplitude-modulated reference signal 111 can be generated by alternating sections with reflected radar signals and sections without reflected radar signals. By adjusting the rotation speed as desired, a reference signal modulated at any frequency can be generated. Thus, any coding can be applied to the reference signal.

[0087] As an alternative to the FIG 1 bis 4In the embodiments illustrated, the reference signal unit 109 can be arranged, for example, on vehicles. Thus, information concerning the respective vehicle can be exchanged via appropriately modulated reference signals via corresponding radar sensor units, which are either installed stationary on a road or rail section to be monitored or installed on other vehicles.

[0088] This allows information regarding the traffic situation to be exchanged between individual vehicles. Alternatively, information can be exchanged between a stationary system and a moving vehicle. For example, a signal or information transmitted by another vehicle or a stationary sensor unit can be confirmed as received via the reference signal unit installed on a vehicle using an appropriately modulated reference signal.

Claims

1. System (100) for monitoring a traffic situation, comprising: at least one radar sensor unit (101) for receiving environmental data for a monitoring region (103) of the radar sensor unit (101), wherein the radar sensor unit (101) is configured to transmit radar signals (105) in the direction of the monitoring region (103), to receive radar signals (105) reflected by objects within the monitoring region (103) to the radar sensor unit (101) and to generate environmental data for the monitoring region (103) based on the radar signals received (105); a processor unit (107) for evaluating the environmental data from the radar sensor unit (101) and for determining the traffic situation within the monitoring region (103) on the basis of the environmental data from the radar sensor unit (101); and a reference signal unit (109) for outputting a reference signal to the radar sensor unit (101), wherein the reference signal unit (109) is configured to provide a radar signal (105) transmitted by the radar sensor unit (101) with a modulation and to reflect the modulated radar signal back to the radar sensor unit (101) as a reference signal (111), and wherein the processor unit (107) is configured to identify the modulated radar signal (105) as the reference signal (111) from the reference signal unit (109), characterized in that the processor unit (107) is configured to detect a malfunction of the radar sensor unit (101) if no reference signal (111) is received by the radar sensor unit (101), wherein the reference signal unit (109) has a first reflection state and a second reflection state, and wherein a radar signal (105) reflected by the reference signal unit (109) in the first reflection state deviates in at least one property from a radar signal (105) reflected by the reference signal unit (109) in the second reflection state, and wherein the reference signal unit (109) is connectable with a switching frequency alternately between the first reflection state and the second reflection state.

2. System (100) according to Claim 1, wherein the reference signal unit (109) has a first reflection surface (141), which is configured to reflect radar signals (105) from the radar sensor unit (101), wherein in the first reflection state, the reflection surface has been brought into a reflection position, in which a reflection of the radar signals from the radar sensor unit (101) is possible, and wherein in the second reflection state, the reflection surface has been brought into a non-reflection position, in which a reflection of the radar signals (105) from the radar sensor unit (101) is prevented.

3. System (100) according to Claim 2, wherein the reference signal unit (109) further has a second reflection surface (143), wherein the second reflection surface (143) is configured to reflect radar signals (105) from the radar sensor unit (101), and wherein in the second reflection state, the second reflection surface (143) has been brought into a reflection position, in which a reflection of the radar signals (105) from the radar sensor unit (101) by the second reflector unit is possible.

4. System (100) according to Claim 3, wherein the first reflection surface (141) and the second reflection surface (143) are arranged at different distances from the radar sensor unit (101).

5. System (100) according to any of Claims 2 to 4, wherein the reference signal unit (109) comprises a first antenna array (147) and / or a second antenna array (149), wherein the first antenna array (147) and / or second antenna array (149) is configured to reflect radar signals (105) from the radar sensor unit (101), and wherein the first reflection surface (141) and / or the second reflection surface (143) is formed by the first antenna array (147) and / or the second antenna array (149).

6. System (100) according to any of Claims 2 to 4, wherein the reference signal unit (109) comprises a reflector body (155) having at least one body surface (157), wherein a reflection layer (159) has been applied to the at least one body surface (157), wherein the reflection layer (159) is configured to reflect radar signals (105), and wherein the first reflection surface (141) and / or the second reflection surface (143) is formed by the reflection layer (157) applied to the at least one body surface (157).

7. System (100) according to any of the preceding claims, wherein the radar sensor unit (101) is positioned in a fixed location on a road section (113) or rail section (121) to be monitored, and wherein the reference signal unit (109) is positioned in a fixed location in the monitoring region (103) of the radar sensor unit (101).

8. System (100) according to any of the preceding claims, further comprising a further radar sensor unit (123) for recording environmental data for a further monitoring region (125) of the further radar sensor unit (123), wherein the further radar sensor unit (123) is configured to transmit further radar signals (127) in the direction of the further monitoring region (125), to receive radar signals reflected by objects within the further monitoring region (125) to the further radar sensor unit (123) and to generate further environmental data for the further monitoring region (103) on the basis of the received further radar signals (127); a further processor unit (131) for evaluating the further environmental data from the further radar sensor unit (123) and for determining the traffic situation within the further monitoring region (125) on the basis of the further environmental data from the further radar sensor unit (123), wherein the reference signal unit (109) is configured to provide further radar signals (127) transmitted by the further radar sensor unit (123) with the modulation and to reflect a further modulated radar signal back to the further radar sensor unit (123) as a further reference signal (129), wherein the further processor unit (131) is configured to identify the further modulated radar signal as the further reference signal (129) from the reference signal unit (109) and to detect a malfunction of the further radar sensor unit (123) if no further reference signal (129) is received by the further radar sensor unit (123), and wherein the further radar sensor unit (123) is arranged on an autonomously driving vehicle (115).

9. System (100) according to any of the preceding claims, wherein the switching frequency is between 60 MHz and 85 MHz.