Radar device for vehicle

Abstract

The radar device of one aspect of the present disclosure has an object detection unit (84), a multipath ghost determination unit (87), a monorail environment determination unit (88), and a monorail vehicle determination unit (89). The multipath ghost determination unit extracts a relay reflection object from the detected objects, and determines a moving body that is erroneously detected due to a stationary object that relays a radar wave to be a multipath ghost. The monorail environment determination unit determines whether the traveling environment is a monorail environment, and the monorail vehicle determination unit determines the relay reflection object to be a monorail vehicle based on the number of multipath ghosts when the traveling environment is a monorail environment.

Description

Technical Field

[0001] This disclosure relates to a vehicle radar device that detects objects around a vehicle by transmitting and receiving radar waves. Background Technology

[0002] Patent Document 1 describes a vehicle radar device configured to detect the distance, speed, and orientation of objects around the vehicle by radiating radar waves around the vehicle and receiving the reflected waves of the radar waves, and output the detection results to a driving assistance device mounted on the vehicle.

[0003] According to the vehicle's radar device, while the vehicle is in motion, it detects objects present in front of it in the direction of travel and outputs the information to the driving assistance device to implement driving assistance to avoid collisions with the objects.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2020-173164

[0005] However, in some vehicle operating environments, there are cases where a suspended monorail is erected above the vehicle's path, allowing monorail vehicles to travel. In such environments, vehicle radar devices should consider detecting monorail vehicles traveling in front of the vehicle as moving objects that obstruct the vehicle's movement.

[0006] In this situation, because the vehicle's radar device outputs the detection results of the monorail vehicle to the driving assistance device, the driving assistance device provides collision avoidance assistance even though the monorail vehicle does not obstruct the vehicle's movement. Therefore, in this case, a problem arises where the vehicle is miscontrolled due to the driving assistance device's assistance. Summary of the Invention

[0007] One aspect of this disclosure is to enable a vehicle radar device to determine that a detected object is a monorail vehicle.

[0008] One aspect of this disclosure is a vehicle radar device mounted on a vehicle to detect objects around the vehicle, comprising an object detection unit, a multipath ghosting determination unit, a monorail environment determination unit, and a monorail vehicle determination unit.

[0009] The object detection unit detects the position and speed of objects by sending radar waves around the vehicle and receiving the reflected waves, performing frequency analysis of the transmitted and received signals. Additionally, the monorail environment determination unit determines whether the driving environment around the vehicle is a monorail environment where a monorail exists above the vehicle's path.

[0010] The multipath ghosting determination unit extracts moving objects that can relay the transmission and reception of radar waves between the object detection unit and other objects from among multiple objects detected by the object detection unit, and identifies them as relay reflective objects. Furthermore, objects that are stationary objects that relay the transmission and reception of radar waves through these extracted relay reflective objects and are mistakenly detected as moving objects by the object detection unit are determined to be multipath ghosting objects.

[0011] When the monorail environment determination unit determines that the operating environment is a monorail environment, the monorail vehicle determination unit counts the number of objects identified as having multipath ghosting for each relay reflection object in the multipath ghosting determination unit. Furthermore, relay reflection objects whose first determination value, set based on this count, is above a first threshold value are determined to be monorail vehicles.

[0012] In other words, when a suspended monorail is erected above the travel path, a monorail vehicle is detected by the object detection unit as an object in front of the vehicle, and based on the speed of the object, it is determined to be a moving object that obstructs the travel of the vehicle.

[0013] On the other hand, in a suspended monorail, if radar waves are shone onto a monorail vehicle, a portion of the reflected waves will hit the track closer to the monorail vehicle, and the reflected waves reflected by that track will return to the vehicle's radar device via the monorail vehicle.

[0014] In this case, the monorail vehicle becomes a relay reflector for radar waves that travel back and forth between the vehicle's radar device and the track. Furthermore, if the target detection unit receives a reflected wave that travels from the track through the relay reflector, it treats this reflected wave as a reflected wave from a target located further away from the monorail vehicle, and detects the target's position and speed.

[0015] The object detected in this way is a multipath ghosting caused by the reflection of radar waves, which is a misdetection of multipath. However, it corresponds to the actual orbit and detects multiple multipath ghostings caused by reflections from the orbit.

[0016] Therefore, in the vehicle radar device disclosed herein, since the track is a stationary object, the multipath ghosting determination unit determines the object that is mistakenly detected due to the transmission and reception of radar waves by the relay reflector object as a multipath ghosting.

[0017] Furthermore, when the driving environment around the vehicle is a monorail environment, the multipath ghosting determination unit counts the number of multipath ghosts for each relay reflecting object, and determines whether the relay reflecting object is a monorail vehicle based on the count.

[0018] Therefore, according to the radar device for vehicles disclosed herein, it is possible to determine that the detected object is a monorail vehicle and suppress the output of the monorail vehicle as an object that would hinder the movement of the vehicle to external devices such as driving assistance devices.

[0019] Furthermore, since it is not necessary to use images obtained by taking pictures of the area around the vehicle via a camera to determine whether a monorail vehicle is in use, the structure of the device can be simplified. Attached Figure Description

[0020] Figure 1 This is a block diagram illustrating the structure of the radar device according to the implementation method.

[0021] Figure 2 This is an explanatory diagram showing the configuration of the radar device on the vehicle and the monorail environment.

[0022] Figure 3 It is a block diagram representing the functional structure of the processing unit.

[0023] Figure 4 This is an illustrative diagram showing the multipath ghosting phenomenon observed from the side of the vehicle in a monorail environment.

[0024] Figure 5 This is an explanatory diagram showing the multipath ghosting phenomenon observed from above the vehicle in a monorail environment.

[0025] Figure 6 This is a flowchart representing the multipath ghosting detection and processing.

[0026] Figure 7 This is a flowchart representing the single-track environment determination and processing.

[0027] Figure 8 This is a flowchart illustrating the process of determining and handling monorail vehicles. Detailed Implementation

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0029] [structure]

[0030] like Figure 2 As illustrated, the radar device 10 in this embodiment is a vehicle radar device disposed in the central part of the front of the vehicle 2, such as the inside of the front bumper.

[0031] The radar device 10 is used to detect objects in front of the vehicle 2 by emitting radar waves in front of the vehicle 2 equipped with the radar device 10 (hereinafter referred to as the vehicle) and receiving the reflected waves of the radar waves.

[0032] Furthermore, in this embodiment, the radar device 10 is described as detecting an object in front of the vehicle 2, but the radar device 10 may also be installed at the rear of the vehicle 2 to detect objects located behind the vehicle 2.

[0033] like Figure 1 As shown, the radar device 10 includes a transmitting circuit 20, a distributor 30, a transmitting antenna 40, a receiving antenna 50, a receiving circuit 60, a processing unit 70, and an input / output unit 90.

[0034] The transmitting circuit 20 is used to supply the transmitting signal Ss to the transmitting antenna 40. The transmitting circuit 20 inputs the millimeter-wave high-frequency signal to the distributor 30 located upstream of the transmitting antenna 40.

[0035] The transmitting circuit 20 generates an FCW-modulated high-frequency signal, for example, by modulating the frequency of the high-frequency signal from a minimum start frequency to a maximum end frequency and repeating this modulation in stages, and then inputs it to the distributor 30. Therefore, the radar device 10 of this embodiment is an FCM-based radar device.

[0036] However, the radar device 10 could also be an FM-CW radar device in which the transmitting circuit 20 periodically increases / decreases the frequency of the high-frequency signal. Alternatively, it could be a dual-frequency CW radar device in which the transmitting circuit 20 periodically switches the frequency of the high-frequency signal to two stages.

[0037] The distributor 30 distributes the high-frequency signal power input from the transmitting circuit 20 into a transmitted signal Ss and a local signal L. The transmitting antenna 40 radiates radar waves at a frequency corresponding to the transmitted signal Ss, based on the transmitted signal Ss supplied from the distributor 30.

[0038] The receiving antenna 50 is used to receive radar waves, i.e., reflected waves, reflected from a target. The receiving antenna 50 is configured as a linear array antenna with multiple antenna elements 51 arranged in a row. The received signal Sr of the reflected wave reflected by each antenna element 51 is input to the receiving circuit 60.

[0039] The receiving circuit 60 processes the received signals Sr input from each antenna element 51 constituting the receiving antenna 50 to generate and output a beat frequency signal BT for each antenna element 51. Specifically, the receiving circuit 60 generates and outputs the beat frequency signal BT for each antenna element 51 by mixing the received signal Sr input from that antenna element 51 with the local signal L input from the distributor 30 using a mixer 61.

[0040] However, the process up to the output beat frequency signal BT includes amplifying the received signal Sr and removing unnecessary signal components from the beat frequency signal BT.

[0041] Thus, the beat frequency signal BT of each antenna element 51 generated and output by the receiving circuit 60 is input to the processing unit 70.

[0042] The processing unit 70 includes a microcomputer with a CPU 71 and a semiconductor memory (hereinafter, memory 72) such as RAM or ROM. Additionally, the processing unit 70 may also include a coprocessor for performing high-speed Fourier transform (hereinafter, FFT) processing.

[0043] The processing unit 70 performs frequency analysis on the beat frequency signal BT of each antenna element 51, and periodically and repeatedly performs detection actions (hereinafter, object detection processing) to calculate the distance R to the object, the velocity V of the object, and the azimuth θ of the object for each object reflecting the radar wave.

[0044] The velocity V of the target is the relative velocity with respect to the vehicle 2. When the target reflecting the radar wave is stationary, it is approximately "-1 × vehicle speed". In addition, the azimuth θ of the target is calculated by taking the central axis of the radiation direction of the radar wave from the radar device 10 as 0 degrees.

[0045] The detection result of the object by the processing unit 70 is output from the input / output unit 90 to the driving assistance ECU 100 of the vehicle 2. In addition, the input / output unit 90 also uses the processing unit 70 to obtain the vehicle speed, steering angle and other driving status of the vehicle 2 from external devices such as the driving assistance ECU 100.

[0046] Furthermore, ECU is an abbreviation for Electronic Control Unit. The driver assistance ECU 100 performs various processes to assist the driver in driving the vehicle 2 based on the detection results of the target input from the radar device 10.

[0047] Processes related to driver assistance may include, for example, issuing warnings to the driver about approaching objects, and controlling the braking and steering systems of the vehicle 2 to avoid collisions with approaching objects. Additionally, to enable the vehicle 2 to follow a preceding vehicle, processes may include controlling the vehicle 2's drive system, braking system, and operating system.

[0048] [Function of Processing Unit 70]

[0049] Next, as Figure 3As shown, the processing unit 70 includes a frequency analysis unit 82, an object detection unit 84, an object information output unit 86, a multipath ghosting determination unit 87, a single-track environment determination unit 88, and a single-track vehicle determination unit 89 as its functional structure.

[0050] The frequency analysis unit 82 performs A / D conversion on the beat frequency signal BT and inputs it. It then performs a high-speed Fourier transform (FFT) on the digital data of the input beat frequency signal BT to search for targets that exist in the direction of radar wave radiation.

[0051] Specifically, the frequency analysis unit 82 analyzes the distance frequency, for example, by performing FFT processing on the beat frequency signal BT for each chirp of the transmitted signal whose frequency increases from the start frequency to the end frequency through FCM modulation. Additionally, the frequency analysis unit 82 analyzes the velocity frequency by performing FFT processing on the distance frequency in the chirp direction.

[0052] As a result, in the frequency analysis unit 82, through such two-dimensional FFT processing, an analysis result is obtained that generates the peak value of the power spectrum in the coordinate system of distance and velocity. Then, based on the analysis result, the target detection unit 84 determines the target present in the direction of radar wave radiation and calculates the distance R to the target and the velocity V of the target.

[0053] Furthermore, the frequency analysis unit 82 calculates the azimuth θ of each object based on the phase difference of the beat frequency signal BT obtained from each antenna element 51, and the object detection unit 84 determines the position of each object based on the distance R and azimuth θ calculated for each object, and outputs the position along with the object's velocity V to the object information output unit 86. In addition, since the two-dimensional FFT and phase difference-based azimuth detection in the radar device 10 are known technologies, detailed explanations are omitted here.

[0054] The object information output unit 86 outputs object information, representing the distance R, orientation θ, and speed V of each object, from the object detection unit 84 to the driving assistance ECU 100. Furthermore, based on instructions from the monorail vehicle determination unit 89 (described later), the object information output unit 86 restricts the output of object information for objects determined to be monorail vehicles.

[0055] Furthermore, this restriction is achieved by stopping the output of object information or outputting object information supplemented with information indicating that it is a monorail vehicle. As a result, it is possible to prevent the driving assistance ECU 100 from erroneously implementing driving assistance such as reverse maneuvering when the object is actually a monorail vehicle.

[0056] Next, the multipath ghosting determination unit 87, the monorail environment determination unit 88, and the monorail vehicle determination unit 89 are used to... Figure 2In the illustrated monorail environment, the function of determining that the object detected by the object detection unit 84 is the monorail vehicle 6 is defined. Furthermore, the so-called monorail environment refers to the operating environment of a suspended monorail railway in which the monorail vehicle 6 is suspended and travels above the travel path of this vehicle 2.

[0057] The multipath ghosting determination unit 87 determines objects that are mistakenly detected because radar waves hit a moving object traveling in front of the vehicle 2 and are reflected, and a portion of the reflected wave hits a stationary object in the vicinity and returns to the vehicle 2 via the same moving object, as multipath ghosting.

[0058] In other words, such as Figure 4 , Figure 5 As shown, in a monorail environment, when the object detection unit 84 detects the monorail vehicle 6, the radar wave hits the monorail vehicle 6 and is reflected by the reflection point P1 of the monorail vehicle 6.

[0059] Furthermore, there is a possibility that a portion of the reflected wave from the reflection point P1 hits the track 4 on which the monorail vehicle 61 is suspended, and returns from the reflection point P2 of the track 4 to the radar device 10 via the monorail vehicle 6. In this case, the monorail vehicle 6 becomes a relay reflector target for relaying radar waves between the radar device 10 and the track 4.

[0060] If such a multipath occurs, the object detection unit 84 will mistakenly detect the object that becomes the multipath ghost 8 as existing on the opposite side of the reflection point P1 and reflection point P2 separated by the monorail vehicle 6 due to the reflected wave reflected from the track 4.

[0061] Therefore, the multipath ghosting determination unit 87 is used to identify multipath ghosting 8 from the objects detected by the object detection unit 84.

[0062] Next, the monorail vehicle determination unit 89 determines whether there is a monorail vehicle 6 among the objects detected by the object detection unit 84 based on the determination result of the multipath ghosting 8 by the multipath ghosting determination unit 87.

[0063] Furthermore, if the monorail vehicle determination unit 89 determines that the object detected by the object detection unit 84 is the monorail vehicle 6, it will restrict the object information of the monorail vehicle 6 from being output from the object information output unit 86 to the driving assistance ECU 100.

[0064] However, in the object detection unit 84, even if the relay reflection object of the radar wave between the radar device 10 and the surrounding stationary objects is not the monorail vehicle 6, the object that becomes a multipath ghosting 8 can be detected.

[0065] For example, when radar waves reflected by other vehicles traveling in front of this vehicle 2 hit the guardrail, and the reflected waves from the guardrail return to the radar device 10 via other vehicles, the object detection unit 84 also detects the object as a multipath ghosting 8.

[0066] In order to correctly determine that the relay reflection target is the monorail vehicle 6 based on the determination result of the multipath ghosting 8 by the multipath ghosting determination unit 87 in the monorail vehicle determination unit 89, a monorail environment determination unit 88 is provided.

[0067] In other words, the monorail environment determination unit 88 determines whether the driving environment around the vehicle 2 is a monorail environment. If it is a monorail environment, the monorail vehicle determination unit 89 determines the monorail vehicle 6. As a result, the monorail vehicle determination unit 89 can suppress the misdetermination of the monorail vehicle 6.

[0068] Next, according to Figures 6-8 The flowcharts explain the operation of the multipath ghosting determination unit 87, the monorail environment determination unit 88, and the monorail vehicle determination unit 89.

[0069] also, Figures 6-8 The process shown is a process that is executed periodically in sync with the object detection process by the CPU 71, and is implemented by the CPU 71 executing the program stored in the memory 72.

[0070] [Multi-path ghosting detection and processing]

[0071] Figure 6 The multipath ghosting determination process is executed in CPU 71 to realize the function of the multipath ghosting determination unit 87.

[0072] like Figure 6 As shown, if this process begins, in S110, a moving object that will serve as a relay reflection object is first selected from among a plurality of objects detected by the object detection process. Each time S110 is executed, the moving object closest to the vehicle 2 is sequentially selected from among the plurality of objects detected by the object detection unit 84, thereby implementing the relay reflection object selection in S110. Furthermore, since the speed of a stationary object corresponds to the speed of the vehicle 2, the determination of whether the object is a moving object or a stationary object is based on the speed of the object, specifically based on the relative speed between the vehicle 2 and the object and the speed of the vehicle 2.

[0073] Next, in S120, the vehicle speed Vs of the vehicle 2 is obtained from the driver assistance ECU 100 via the input / output unit 90. Then, based on the obtained vehicle speed Vs and the distance R, azimuth θ, and velocity V of the target selected as a relay reflector in S110, the multipath ghosting condition is calculated.

[0074] The multipath ghosting condition specifies the distance Rg and orientation θg from vehicle 2 to multipath ghosting 8, and the relative speed between vehicle 2 and multipath ghosting 8, i.e., the multipath ghosting speed Vg.

[0075] The multipath ghosting speed Vg[m / s] is estimated based on the relative speed between the relay reflector and the vehicle 2, i.e., the speed of the relay reflector Vr[m / s], the orientation of the relay reflector θr[deg], and the speed of the vehicle 2, i.e., the vehicle speed Vs[m / s].

[0076] The following formula is used in this estimation, for example.

[0077] Vg[m / s]=2×Vr[m / s]+Vs[m / s]×cosθr[deg]

[0078] This is because the radar wave, which is reflected by stationary objects such as track 4 and relayed through the relay reflector, passes through the relay reflector twice and enters the radar device 10 at an angle approximately the same as the azimuth θr[deg] of the relay reflector, and the speed of the stationary object corresponds to the vehicle speed Vs[m / s] of the vehicle 2.

[0079] Furthermore, if the object that will be the target of the multipath ghosting 8 is used as the target to be determined, the multipath ghosting conditions include the following three conditions 1 to 3.

[0080] Condition 1: The distance of the target being judged, Rt[m], minus the distance of the relay-reflecting target, Rr[m], is greater than the distance difference threshold, ΔR[m].

[0081] Condition 2: |The velocity of the object being judged, Vt[m / s] - the multipath ghosting velocity, Vg[m / s]| < the velocity difference threshold △V[m / s]

[0082] Condition 3: |Azimuth of the target being determined θt[deg] - Azimuth of the relay-reflected target θr[deg]| < Azimuth difference threshold[deg]

[0083] In other words, condition 1 means that the distance from vehicle 2 to the target being judged, i.e., the distance Rt[m] to the target being judged, is longer than the preset distance difference threshold △R[m] compared to the distance Rr[m] to the relay reflection target.

[0084] Furthermore, condition 2 indicates that the absolute value of the difference between the relative speed of vehicle 2 and the target object, i.e., the target object speed Vt [m / s] and the multipath ghosting speed Vg [m / s] calculated by the above formula, is smaller than the preset speed difference threshold ΔV [m / s]. In other words, condition 2 indicates that the target object speed Vt [m / s] and the multipath ghosting speed Vg [m / s] are approximately the same.

[0085] Additionally, condition 3 indicates that the absolute value of the difference between the azimuth θt[deg] of the determined object and the azimuth θr[deg] of the relay reflector object is smaller than the pre-set azimuth difference threshold Δθ[deg]. In other words, condition 3 indicates that the azimuth θt[deg] of the determined object and the azimuth θr[deg] of the relay reflector object are approximately the same.

[0086] Next, in S130, a stationary object with a longer distance from the vehicle 2 than the relay reflection object is selected from the multiple objects detected by the object detection unit 84 as the object to be judged, and then moved to S140.

[0087] Furthermore, the selection of targets is performed sequentially, starting from the target closest to the vehicle 2. Additionally, as a selection criterion for the target, besides the distance to the vehicle 2, it can also be set to select targets located within a specified angular range centered on the orientation of the relay-reflecting target.

[0088] In S140, the distance R, orientation θ, and velocity V of the object selected as the object to be judged in S130 are obtained respectively, and are used as the aforementioned distance Rt, orientation θt, and velocity Vt of the object to be judged.

[0089] Then, in S150, it is determined whether the distance Rt, orientation θt, and velocity Vt of the target obtained in S140 meet the conditions 1 to 3 above, respectively.

[0090] In S150, when the distance Rt, orientation θt, and velocity Vt of the target all meet conditions 1 to 3, the multipath ghosting condition is met, and the process moves to S152. In S152, the ghosting counter for the currently selected target is incremented by 1, and the process moves to S160.

[0091] If the condition for determining multipath ghosting is not met in S150, proceed to S154. In S154, the ghosting counter for the currently selected object is decremented by 1, and then proceed to S160.

[0092] In addition, the minimum value of the ghost counter is 0. When the multipath ghost condition is not met, the ghost counter is decremented by 1 and is not updated to a negative value.

[0093] Next, in S160, it is determined whether the value of the ghost counter, which has been updated as described above, exceeds a preset threshold. Furthermore, if the value of the ghost counter exceeds the threshold, it is determined that the target being judged is multipath ghosting 8, and the process moves to S170, where the ghosting flag for the target being judged is set. As a result, the case where the currently selected target being judged is multipath ghosting 8 is stored in the memory 72 or register of the processing unit 70.

[0094] When the ghosting flag is set in S170 or when the value of the ghosting counter is determined to be below the threshold in S160, proceed to S180. In S180, it is determined whether the selection of the target object has ended by determining whether all objects that meet the selection conditions have been selected as the target object in S130.

[0095] Furthermore, if it is determined in S180 that the selection of the object to be judged has ended, then proceed to S190; if it is determined in S180 that the selection of the object to be judged has not ended, then proceed to S130 and execute the processing after S130 again.

[0096] In S190, the selection of relay reflection targets is determined by whether a predetermined number of relay reflection targets were selected in S110. If it is determined in S190 that the selection of relay reflection targets has ended, the multipath ghosting determination process ends. If it is determined in S190 that the selection of relay reflection targets has not ended, the process moves to S110 and executes the subsequent processes again.

[0097] Thus, in the multipath ghosting determination process, for each object detected by the object detection process, which is the object detection unit 84, it is determined whether it is a multipath ghosting 8. If it is a multipath ghosting 8, the ghosting flag for that object is set.

[0098] Furthermore, since the object for which the ghosting flag is set is actually a multipath ghosting 8 that does not exist, the output of object information from the object information output unit 86 to the driver assistance ECU 100 can also be prohibited. Alternatively, information indicating that it is a multipath ghosting 8 can be added to the object information, and this information can be output from the object information output unit 86 to the driver assistance ECU 100.

[0099] [Monorail Environment Assessment and Handling]

[0100] Figure 7 This is a single-track environment determination process executed in CPU71 to realize the function of the single-track environment determination unit 88.

[0101] like Figure 7As shown, in the single-track environment determination process, firstly in S210, it is determined whether the determination condition for a single-track environment is met. The determination condition for a single-track environment is, for example, set to not be met when the vehicle 2 is stationary or turning. That is, the determination condition for a single-track environment is set to be met when the vehicle 2 is traveling straight.

[0102] This is because, in radar device 10, the monorail track 4 is detected as multiple objects arranged in a line along track 4. Additionally, when the monorail vehicle 6 is traveling, track 4 is detected as multiple multipath ghostings 8 arranged in a line along track 4.

[0103] In other words, when the vehicle 2 is stopped or turning, there are situations where it is impossible to detect continuous objects or multi-path ghosting 8 along the track 4. Therefore, in this embodiment, the determination condition of the single-track environment is met when the vehicle 2 is traveling straight.

[0104] In S210, if the determination condition for a single-track environment is not met, the single-track environment determination process ends; if the determination condition for a single-track environment is met, the process moves to S220.

[0105] In S220, the number of stationary objects arranged in a line in front of the vehicle 2 and the number of multipath ghosting 8 are counted from the objects detected by the object detection process. Furthermore, the number of multipath ghosting 8 is determined by... Figure 6 The multipath ghosting detection process determines the number of objects in multipath ghosting 8 that are arranged in a linear shape in front of the vehicle 2.

[0106] Next, in S230, the environment determination score is updated based on the counts of stationary objects and multipath ghosting 8 counted in S220, so that the higher the count, the higher the environment determination score. Conversely, if the count is low, the environment determination score is updated to reduce the overall environment determination score.

[0107] Then, in S240, it is determined whether the environmental determination score updated in S230 exceeds the preset environmental determination threshold. If the environmental determination score does not exceed the environmental determination threshold, the single-track environmental determination process ends.

[0108] In addition, in S240, if the environmental determination score is determined to exceed the environmental determination threshold, then in S250, the driving environment of the vehicle 2 is determined to be a single-track environment, the meaning is stored in the memory 72 or register, and the single-track environment determination process ends.

[0109] Furthermore, in S240, if it is determined that the environmental score does not exceed the environmental determination threshold, that is, if it is determined that the driving environment of the vehicle 2 is not a monorail environment, the storage of a monorail environment is eliminated. Additionally, in this embodiment, the environmental determination score is equivalent to the second determination value of this disclosure, and the environmental determination threshold is equivalent to the second threshold of this disclosure.

[0110] Thus, in the monorail environment determination process, the number of stationary objects arranged in a line in front of the vehicle 2 and the number of multipath ghosting 8 are counted from the objects detected by the object detection process, and based on the count, it is determined whether there is a track 4 around the vehicle 2. Therefore, it is possible to correctly determine that the driving environment of the vehicle 2 is a monorail environment.

[0111] Furthermore, determining whether the driving environment of vehicle 2 is a monorail environment does not necessarily require performing monorail environment determination processing. In other words, for example, the monorail environment determination unit 88 can obtain map information from a navigation device or the like, and determine whether the driving environment around vehicle 2 is a monorail environment based on that map information.

[0112] Alternatively, for example, if a single-track environment is detected using map information, the single-track environment determination process can be implemented by changing the environment determination threshold to one that is more easily identified as a single-track environment. This allows for faster identification of single-track environments and improves the accuracy of single-track environment determination.

[0113] [Monorail Vehicle Identification and Handling]

[0114] Figure 8 This is a monorail vehicle determination process executed in CPU 71 to realize the function of the monorail vehicle determination unit 89.

[0115] like Figure 8 As shown, in the monorail vehicle determination process, firstly in S310, based on the determination result of the monorail environment determination process, it is determined whether the driving environment of vehicle 2 is a monorail environment. Moreover, if the driving environment of vehicle 2 is not a monorail environment, the monorail vehicle determination process ends; if the driving environment of vehicle 2 is a monorail environment, the process moves to S320.

[0116] In S320, one of the relay reflection targets that is determined to be a multipath ghost 8 by the multipath ghost detection process is extracted and moved to S330. In S330, the number of multipath ghosts 8 that are mistakenly detected as targets due to the relay radar waves of the extracted relay reflection targets is counted.

[0117] This is because the multipath ghosting 8, which is mistakenly detected as a relay reflecting object, appears as multiple objects that are linearly continuous along the track 4. In other words, in S330, by counting the number of multipath ghostings 8 that are mistakenly detected due to a relay reflecting object, it is possible to determine whether the relay reflecting object is the monorail vehicle 6 based on the count.

[0118] Next, in S340, the vehicle determination score is updated based on the count of multipath ghosting 8 counted in S330, so that the higher the count, the higher the vehicle determination score. Conversely, if the count is low, the vehicle determination score is updated to reduce the vehicle determination score.

[0119] In S350, it is determined whether the vehicle determination score updated in S340 exceeds a preset vehicle determination threshold. Then, in S350, if it is determined that the vehicle determination score exceeds the vehicle determination threshold, the process moves to S360, where the relay reflector extracted in S320 is identified as monorail vehicle 6.

[0120] In addition, in S360, the case that the relay reflection target is a monorail vehicle 6 is stored in the memory 72 or a register, etc., the output of the target information of the monorail vehicle 6 from the target information output unit 86 is restricted, and the monorail vehicle determination process ends.

[0121] On the other hand, in S350, if the vehicle determination score is determined not to exceed the vehicle determination threshold, the process moves to S370. In S370, it is determined whether there are other relay reflection targets besides the relay reflection targets extracted in S320 after the start of the monorail vehicle determination process, which are targets that are determined to be multipath ghosting 8 by the multipath ghosting determination process.

[0122] Furthermore, if other relay reflective targets are identified in S370, the process moves to S320 to extract these other relay reflective targets and executes the processing from S330 onwards. Conversely, if no other relay reflective targets are identified in S370, meaning the determination of monorail vehicle 6 for all relay reflective targets is complete, then the monorail vehicle determination process ends because monorail vehicle 6 was not detected as a target.

[0123] [Effect]

[0124] As explained above, in the radar device 10 of this embodiment, multipath ghosting 8 is detected by determining whether the object detected by transmitting and receiving radar waves is a multipath ghosting 8. Furthermore, for each relay reflection object that causes the detected multipath ghosting 8, the number of multipath ghosting 8 generated by the relay reflection object is counted, and based on the count, the relay reflection object is determined to be a monorail vehicle 6.

[0125] In addition, multipath ghosting conditions are set based on the position and speed of the selected relay reflection targets and the speed of the vehicle, and targets that meet the set multipath ghosting conditions are extracted to determine multipath ghosting 8.

[0126] Therefore, according to the radar device 10 of this embodiment, it is possible to determine whether the object detected by the object detection unit 84 is a monorail vehicle 6 simply by using the detection result of the object by the object detection unit 84. Therefore, according to the radar device 10 of this embodiment, it is not necessary to perform image processing on the captured image of the vehicle 2 and its surroundings to identify the monorail vehicle 6 in order to determine the monorail vehicle 6, but can easily determine the monorail vehicle 6.

[0127] Furthermore, in this embodiment, it is determined whether the driving environment of the vehicle 2 is a monorail environment. If the driving environment is a monorail environment, it is determined whether the detected object is a monorail vehicle 6. Therefore, when the driving environment is not a monorail environment, the monorail vehicle 6 will not be mistakenly identified, thus improving the accuracy of the identification of the monorail vehicle 6.

[0128] [Other Implementation Methods]

[0129] The embodiments of this disclosure have been described above, but this disclosure is not limited to the above embodiments and can be implemented in various ways.

[0130] For example, in this embodiment, the object detected by the object detection unit 84 is determined to be a monorail vehicle 6 based solely on the detection result of the object detection unit 84, but this determination can also be made using images captured by a camera.

[0131] In other words, an image recognition unit is set up to identify the monorail vehicle 6 based on an image captured by a camera of the front of the vehicle 2. When the image recognition unit identifies the monorail vehicle 6, the monorail vehicle determination unit 89 determines that the monorail vehicle 6 is the monorail vehicle. In this way, it is possible to more accurately determine that the detected object is the monorail vehicle 6.

[0132] On the other hand, consider, for example, the situation where the monorail vehicle 6 becomes a relay reflector for radar waves from track 4, similarly occurring in the truck and the superstructure, and a multipath ghosting 8 configured as a line is detected. However, in this case, the height of the monorail vehicle 6, which becomes the relay reflector, is significantly different from the height of the truck; the monorail vehicle 6 is taller.

[0133] Therefore, the determination of the monorail vehicle 6 can also be made when the height of the relay reflector corresponds to the height of the monorail vehicle 6. Furthermore, the height of the relay reflector can be determined based on its distance and orientation to the relay reflector.

[0134] However, the detection accuracy of the height of the relay reflector in this way varies depending on the axial offset and distance of the radar wave transceiver. Therefore, if the determination criteria for monorail vehicle 6 include the height of the relay reflector, the determination of monorail vehicle 6 can be performed while ensuring the detection accuracy of the distance and height to the relay reflector.

[0135] Next, in the above embodiment, the case where the monorail vehicle determination unit 89 determines whether the relay reflective object is the monorail vehicle 6 when the monorail environment determination unit 88 determines that it is a monorail environment is described.

[0136] However, the monorail vehicle determination unit 89 can always perform the determination of the monorail vehicle 6, and only output the determination result of the monorail vehicle 6 to the object information output unit 86 when the monorail environment determination unit 88 determines that it is a monorail environment.

[0137] Next, the method for determining the monorail vehicle 6 performed by the processing unit 70 can also be implemented by a dedicated computer, which is provided by a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the method for determining the monorail vehicle 6 performed by the processing unit 70 can also be implemented by a dedicated computer, which is provided by a processor composed of one or more dedicated hardware logic circuits. Alternatively, the method for determining the monorail vehicle 6 performed by the processing unit 70 can also be implemented by one or more dedicated computers composed of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits.

[0138] Furthermore, the computer program executed in the processing unit 70 can also be stored as instructions executable by a computer on a computer-readable non-transferable tangible recording medium. Additionally, the method for implementing the functions of each component included in the processing unit 70 does not necessarily require software; all its functions can be implemented using one or more hardware components.

[0139] Multiple functions of a single component in the above embodiments can be achieved through multiple components, or a single function of a single component can be achieved through multiple components. Alternatively, multiple functions of multiple components can be achieved through a single component, or a single function achieved by multiple components can be achieved through a single component. Furthermore, a portion of the structure in the above embodiments can be omitted. Additionally, at least a portion of the structure in the above embodiments can be added to or replaced with the structure of other above embodiments.

[0140] In addition to the vehicle radar device described above, this disclosure can also be implemented in various ways, such as a system that includes the vehicle radar device, a program for enabling a computer to function as the vehicle radar device, a non-transitional physical recording medium such as a semiconductor memory that records the program, and a rainfall determination method in the vehicle radar device.

Claims

1. A vehicle radar device, mounted on a vehicle, for detecting objects around the vehicle, the vehicle radar device comprising: The object detection unit is configured to detect the position and speed of the object by transmitting radar waves to the vicinity of the vehicle and receiving the reflected waves of the radar waves, and performing frequency analysis of the transmitted and received signals. The multipath ghosting determination unit is configured to extract, from the multiple objects detected by the object detection unit, a moving object capable of relaying the transmission and reception of radar waves between the object detection unit and other objects as a relay reflection object, and to determine objects that are mistakenly detected as moving objects by the object detection unit because they are stationary objects that relay the transmission and reception of radar waves through the relay reflection object as multipath ghosting. The monorail environment determination unit is configured to determine whether the driving environment around the vehicle is a monorail environment in which a monorail exists above the vehicle's driving path; and The monorail vehicle determination unit is configured such that, when the monorail environment determination unit determines that the driving environment is the monorail environment, the multipath ghosting determination unit counts the number of objects that are determined to be multipath ghosting for each of the relay reflection objects, and determines the relay reflection objects that are determined to be monorail vehicles if the first determination value set based on the number of the count is above a first threshold.

2. The vehicle radar device according to claim 1, wherein, The aforementioned single-track environment determination unit is configured as follows: The number of stationary objects detected in the object detection unit as arranged in a line in front of the vehicle's direction of travel and the number of multipath ghosting objects determined in the multipath ghosting determination unit as arranged in a line in front of the vehicle's direction of travel are determined to be the vehicle's driving environment as a monorail environment when the second determination value set based on the number of counts is above the second threshold.

3. The vehicle radar device according to claim 1 or claim 2, wherein, The above-mentioned multipath ghosting detection unit is configured as follows: For each relay-reflecting object extracted from the plurality of objects detected by the aforementioned object detection unit, a multipath ghosting condition is set based on the position and speed of the relay-reflecting object and the speed of the vehicle. Objects that meet the multipath ghosting condition are extracted from the plurality of objects detected by the aforementioned object detection unit, and the extracted objects are determined to be multipath ghosts. The multipath ghosting condition refers to the position and speed of the object that is mistakenly detected by the aforementioned object detection unit because the radar wave is relayed by the aforementioned relay-reflecting object.

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