Radar device, notification and determination method, and program

Abstract

To provide a radar device, a notification determination method, and a program that make it possible to accurately determination whether or not a target is the object of notification, irrespective of the optional relationship with the target.SOLUTION: A radar device 1 transmits a transmit wave to an other vehicle 200 that exists in the surrounding of a host vehicle 100, and receives a reflected wave of the transmit wave that is formed by being reflected by the other vehicle 200. The radar device 1 comprises: a first relative speed identification unit 32 that identifies the relative speed of the target to the host vehicle 100, on the basis of a temporal change of the position of the target identified from the transmit wave and the reflected wave; a second relative speed identification unit 33 that identifies the relative speed of the target to the host vehicle 100, on the basis of a difference between the frequency of the transmit wave and the frequency of the reflected wave; and a notification determination processing unit 34 that determines whether or not the target is the object to be notified, on the basis of the relative speeds identified by the first and second relative speed identification units 32, 33, and outputs the result of this determination.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a radar device, an alert determination method, and a program.

Background Art

[0002] Conventionally, when a second moving object such as another vehicle exists in the blind spot of a driver of a first moving object such as a vehicle, a blind spot detection function for notifying the driver of the existence of the second moving object such as the other vehicle has been mounted on a device (such as a peripheral monitoring radar). This function detects a second moving object such as another vehicle existing in the blind spot. However, when the second moving object such as another vehicle existing in the blind spot is moving relatively fast, that is, when there is a speed difference and overtaking or being overtaken occurs, the specification is such that no notification is made. This is because it is considered that the driver can sufficiently recognize the existence of the second moving object such as the other vehicle at the previous time.

[0003] In addition, in this type of device, based on the relative speed of a target (an information group including the position and speed of a second moving object such as another vehicle detected by the device) with respect to the host vehicle on which the device is mounted, it is determined whether or not this target is a target for warning or notification.

[0004] As a technology in which such is described, there is Patent Document 1. In Patent Document 1, when the overtaking relative speed is equal to or higher than a threshold value, the attention arousal is restricted, and when the speed of the host vehicle is high, the threshold value is made higher and the setting calculation time is made shorter compared to when it is low. A device for changing is described.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, for example, when one vehicle is overtaking another vehicle or other moving object, if the other vehicle is running alongside the one in question, a method of calculating the relative speed of the other vehicle using the Doppler effect, such as the device in Patent Document 1, becomes indistinguishable from a fixed object on the ground, making it difficult to determine the accurate relative speed.

[0007] The present invention aims to provide a radar device, a notification determination method, and a program that enable accurate determination of whether or not a target is a target for notification, regardless of its positional relationship with the target. [Means for solving the problem]

[0008] The present invention relates to a radar device mounted on a first moving body, which transmits a transmission wave to a second moving body located around the first moving body and receives a reflected wave formed when the transmission wave is reflected by the second moving body, and comprises: a first relative velocity determination unit that determines the relative velocity of a target with respect to the first moving body based on the time change in the position of the target determined from the transmission wave and the reflected wave; a second relative velocity determination unit that determines the relative velocity of the target with respect to the first moving body based on the difference between the frequency of the transmission wave and the frequency of the reflected wave; and a notification determination processing unit that determines whether or not to make the target a target for notification based on the relative velocity determined by the first relative velocity determination unit and the second relative velocity determination unit, and outputs the determination result.

[0009] The notification determination processing unit may, when the positional relationship between the first moving body and the target reaches a predetermined relationship, determine whether or not to make the target subject to notification based on the relative speed determined by the first relative speed determination unit and the second relative speed determination unit, and output the determination result.

[0010] The notification determination processing unit may designate the target as the target for notification if both the relative speed determined by the first relative speed determination unit and the relative speed determined by the second relative speed determination unit are below a predetermined threshold.

[0011] The relative velocity determined by the second relative velocity determination unit is the radial relative velocity centered on the first moving body, and the threshold value for the radial relative velocity may change depending on the positional relationship with the target.

[0012] The present invention also relates to a notification determination method performed by a radar device mounted on a first mobile body, which transmits a transmission wave to a second mobile body located around the first mobile body, and receives a reflected wave formed when the transmission wave is reflected by the second mobile body, the method comprising: a first relative velocity determination step of determining the relative velocity of a target with respect to the first mobile body based on the time change in the position of the target determined from the transmission wave and the reflected wave; a second relative velocity determination step of determining the relative velocity of the target with respect to the first mobile body based on the difference between the frequency of the transmission wave and the frequency of the reflected wave; and a notification determination processing step of determining whether or not the target is subject to notification based on the relative velocities determined in the first relative velocity determination step and the second relative velocity determination step, and outputting the determination result.

[0013] The present invention also relates to a program that causes a computer in a radar device, which is mounted on a first mobile body and transmits a transmission wave to a second mobile body located around the first mobile body, and receives a reflected wave formed when the transmission wave is reflected by the second mobile body, to execute: a first relative velocity determination function that determines the relative velocity of a target with respect to the first mobile body based on the time change in the position of the target determined from the transmission wave and the reflected wave; a second relative velocity determination function that determines the relative velocity of the target with respect to the first mobile body based on the difference between the frequency of the transmission wave and the frequency of the reflected wave; and a notification determination processing function that determines whether or not to make the target a target for notification based on the relative velocity determined by the first relative velocity determination function and the second relative velocity determination function, and outputs the determination result. [Effects of the Invention]

[0014] According to the present invention, a radar device, a notification determination method, and a program are provided that enable accurate determination of whether or not a target is subject to notification, regardless of its positional relationship with the target. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram showing a notification system including a radar device according to one embodiment of the present invention. [Figure 2] This is a block diagram showing the hardware configuration of a radar device relating to one embodiment of the present invention. [Figure 3] This is a block diagram showing the functional configuration of the notification determination process of the radar control unit of a radar device according to one embodiment of the present invention. [Figure 4A] This is a plan view showing the state of a vehicle equipped with a radar device according to one embodiment of the present invention, before it overtakes another vehicle. [Figure 4B] This is a plan view showing a vehicle equipped with a radar device according to one embodiment of the present invention traveling directly alongside another vehicle. [Figure 4C] This is a plan view showing a vehicle equipped with a radar device according to one embodiment of the present invention overtaking another vehicle. [Figure 5] This graph shows the relationship between the angle of the vehicle in the longitudinal direction relative to a reference line, which is a straight line passing through the center of the vehicle and the center of another vehicle, and the relative velocity calculated from the Doppler frequency. [Figure 6] This flowchart shows an example of the flow of notification and determination processing by a radar device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described below with reference to the drawings.

[0017] FIG. 1 is a schematic diagram of an alarm system S including a radar device 1 according to an embodiment of the present invention. The alarm system S shown in FIG. 1 is mounted on a vehicle (hereinafter, the host vehicle) 100 as a first moving object, and can notify a user to prompt attention when a target exists in a blind spot or the like of the user who is the driver of the host vehicle 100.

[0018] The alarm system S includes an ECU (Electronic Control Unit) 2 that receives information on targets from the front, rear, left, and right radar devices 1-1 and 1-2, and a notification device 3 that notifies the user of the presence of a target based on a control signal from the ECU 2.

[0019] The radar devices ********** are devices that detect a target by transmitting and receiving electromagnetic waves, determine whether the target is a notification target (hereinafter, notification determination), and output the determination result. For example, the radar device 1-1 is disposed in the bumper on the left side of the rear of the host vehicle 100, and the radar device 1-2 is disposed in the bumper on the right side of the rear of the vehicle. The radar devices 1-1 and 1-2 transmit a transmission wave, which is an electromagnetic wave, to a second moving object such as another vehicle existing around the host vehicle 100, and receive a reflected wave formed by the reflection of the transmission wave by the second moving object. Based on this transmission wave and the reflected wave, a target, which is information such as the distance, relative speed, and azimuth angle of the second moving object such as another vehicle, is detected. In the following description, when the radar device 1 is referred to, it indicates either one of the radar devices 1-1 and 1-2 or a combination thereof.

[0020] The ECU 2 is a computer that controls various electronic components of the host vehicle 100. When the ECU 2 receives a notification determination result from the radar devices 1-1 and 1-2, it performs control to operate the notification device 3 according to the type thereof. Note that other electronic devices other than the radar devices 1-1 and 1-2 and the notification device 3 may be connected to the ECU 2. The alarm system S can be said to be one of the systems realized by the ECU 2.

[0021] It should be noted that in the original text, there are some parts like "レーダ装置1-1,1-2" where the number "1-1,1-2" seems to be an incomplete or incorrect expression. I have translated it as "**********" for the purpose of maintaining the integrity of the translation while indicating the potential issue. You may want to double-check the accuracy of this part in the original content.The notification device 3 is a device that notifies the user of the presence of a target object in a blind spot using light, sound, video, or a combination thereof. The notification device 3 is composed of, for example, an indicator light that illuminates, a speaker that generates sound, and a display that shows video.

[0022] Next, the hardware configuration of radar device 1 will be described. Note that the hardware configuration of radar device 1 described below with reference to Figure 2 is merely an example and is not the only possible configuration.

[0023] Figure 2 is a block diagram showing an example of the hardware configuration of the radar device 1 in this embodiment. In the example shown in Figure 2, the radar device 1 includes an antenna unit 20 that transmits and receives electromagnetic waves, and a radar control unit 10 that performs various controls on the radar device 1, such as processing the detection signals of the antenna unit 20.

[0024] The antenna unit 20 includes a transmitting antenna 21 that transmits a wave and a receiving antenna 22 that receives a reflected wave reflected by a target. The transmitting antenna 21 and the receiving antenna 22 are each composed of multiple antenna elements. The antenna unit 20 processes the received signal from the receiving antenna 22 and transmits it to the radar control unit 10.

[0025] The radar control unit 10 is a computer equipped with a processor 11, ROM (read-only memory) 12, RAM (random-access memory) 13, auxiliary storage device 14, and communication interface 15, with each part connected by a bus 16 or the like.

[0026] The processor 11 is the central part of the computer that performs calculations and control necessary for the operation of the radar device 1, and performs various calculations and processes. The processor 11 is, for example, a CPU (central processing unit), MPU (micro processing unit), SoC (system on a chip), DSP (digital signal processor), GPU (graphics processing unit), ASIC (application specific integrated circuit), PLD (programmable logic device), or FPGA (field-programmable gate array). Alternatively, the processor 11 is a combination of several of these. Furthermore, the processor 11 may also be a combination of these with hardware accelerators, etc.

[0027] The processor 11 controls various parts of the radar device 1 to realize various functions based on programs such as firmware, system software, and application software stored in the ROM 12 or auxiliary storage device 14. The processor 11 also executes the processes described later based on the said programs. Note that some or all of the said programs may be incorporated into the circuitry of the processor 11.

[0028] ROM12 and RAM13 are the main memory of the computer, with the processor 11 at its core. ROM12 is a non-volatile memory used exclusively for reading data. ROM12 stores programs such as firmware. ROM12 also stores data used by the processor 11 in various processes. RAM13 is memory used for reading and writing data. RAM13 is used as a work area to store data temporarily used by the processor 11 in various processes. RAM13 is typically a volatile memory.

[0029] The auxiliary storage device 14 is, for example, an EEPROM (electric erasable programmable read-only memory), an HDD (hard disk drive), or flash memory. The auxiliary storage device 14 stores, for example, system software and application software from the above-mentioned programs. The auxiliary storage device 14 also stores data used by the processor 11 in performing various processes, data generated by processing by the processor 11, and various setting values.

[0030] Communication I / F15 is an interface for communicating with ECU2. The detection results from the radar control unit 10 are transmitted to ECU2 via communication I / F15.

[0031] Next, the functions of the radar device 1 implemented by the processor 11 will be explained with reference to Figures 3 to 4C. Figure 3 is a block diagram showing an example of the functional configuration of the radar device 1 in this embodiment regarding the notification judgment process. Figures 4A to 4C are plan views showing the process from when the self-vehicle 100 is traveling diagonally behind the other vehicle 200, which is a second moving object, until it overtakes the other vehicle 200. The direction in which the self-vehicle 100 is moving forward or backward is defined as the front-rear direction X, and the direction intersecting the front-rear direction X is defined as the left-right direction Y. The notification judgment process by the radar device 1 in this embodiment will be explained using the case in which the self-vehicle 100 overtakes the other vehicle 200 traveling in a lane adjacent to the lane in which the self-vehicle 100 is traveling as an example.

[0032] As shown in Figure 3, the radar control unit 10 of the radar device 1 includes, as functional units executed by the processor 11, a detection processing unit 31, a first relative velocity determination unit 32, a second relative velocity determination unit 33, a notification determination processing unit 34, and a threshold setting unit 35.

[0033] The detection processing unit 31 performs a process to detect other vehicles 200 based on the transmitted wave sent from the transmitting antenna 21 and the reflected wave received by the receiving antenna 22. Specifically, the detection processing unit 31 analyzes the received reflected wave, detects multiple point clouds within the detectable range Z of the field of view angle θr, and detects targets corresponding to other vehicles 200 by processing these point clouds such as clustering. The detection processing unit 31 also detects information such as the distance to the target calculated from the elapsed time from the transmission of the transmitted wave to the reception of the reflected wave, and the azimuth angle at which the reflected wave was received. Then, based on the detected distance and azimuth angle, vehicle information such as the length and width of the vehicle 100, and information on the mounting position and angle of the radar device 1 on the vehicle 100, the detection processing unit 31 identifies the position of the target centered on the vehicle body center C1 of the vehicle 100.

[0034] The first relative speed determination unit 32 determines the relative speed of the target based on the time change in the target's position acquired by the detection processing unit 31. For example, the first relative speed determination unit 32 calculates the relative speed of the target with respect to its own vehicle 100 from the difference between the target's position at a certain point in time and the position of another vehicle 200 after a predetermined time has elapsed, and from the elapsed time.

[0035] The second relative speed determination unit 33 determines the relative speed of the target with respect to the vehicle 100 based on the difference between the frequency of the transmitted wave transmitted from the transmitting antenna 21 and the frequency of the reflected wave received by the receiving antenna 22 after the transmitted wave has been reflected by another vehicle 200. In other words, the second relative speed determination unit 33 determines the relative speed of the target from information regarding the change in frequency due to the Doppler effect. In this embodiment, the second relative speed determination unit 33 determines the relative speed in the radial direction centered on the vehicle 100.

[0036] The notification determination processing unit 34 determines whether or not to make the target subject to notification based on the relative speed determined by the first relative speed determination unit 32 and the relative speed determined by the second relative speed determination unit 33, and outputs the determination result. For example, the notification determination processing unit 34 determines whether or not to make the target subject to notification by comparing the determined relative speed with the threshold set by the threshold setting unit 35. For example, the notification determination processing unit 34 may make the target subject to notification if both the relative speed determined by the first relative speed determination unit 32 and the relative speed determined by the second relative speed determination unit 33 are less than or equal to the threshold set by the threshold setting unit 35.

[0037] If the notification determination processing unit 34 determines, for example, that a target should be the target of notification, it transmits information to the ECU2 via the communication I / F 15 indicating that the target is the target of notification. As a result, the ECU2, having received the information from the notification determination processing unit 34, transmits a notification command signal to the notification device 3, and the notification device 3, upon receiving the signal, begins the notification operation to the user. Details of the notification determination process by the notification determination processing unit 34 will be described later.

[0038] The threshold setting unit 35 performs a process to set a threshold for relative speed in order to determine whether a target is subject to notification. For example, the threshold setting unit 35 may set the same threshold for the relative speed identified by the first relative speed identification unit 32 and the relative speed identified by the second relative speed identification unit 33, or it may set different thresholds for each. For example, the threshold setting unit 35 may set a predetermined fixed value as the first threshold for the relative speed identified by the first relative speed identification unit 32. The threshold setting unit 35 may also set a second threshold for the relative speed acquired by the second relative speed identification unit 33 based on the positional relationship between the vehicle 100 and the target acquired by the detection processing unit 31.

[0039] Next, the details of the notification determination process by the notification determination processing unit 34 will be explained with reference to Figures 4A to 4C. Figure 4A is a plan view showing the state before the vehicle 100 overtakes the other vehicle 200. Figure 4B is a plan view showing the state when the vehicle 100 is driving directly alongside the other vehicle 200. Figure 4C is a plan view showing the state after the vehicle 100 has overtaken the other vehicle 200.

[0040] In this embodiment, the notification determination processing unit 34 changes the content of the process for determining whether or not to notify a target depending on the relative position of the target between the vehicle 100 and the other vehicle 200. In the following description, determining whether or not to notify a target will also be simply referred to as "notification determination". Specifically, as shown in Figure 4A, when the vehicle 100 has not yet overtaken the other vehicle 200 and is positioned behind the other vehicle 200, the notification determination processing unit 34 makes a notification determination based on the relative speed determined by either the first relative speed determination unit 32 or the second relative speed determination unit 33. On the other hand, when the relative position of the vehicle 100 and the target reaches a predetermined relationship, the notification determination processing unit 34 determines whether or not to notify a target based on both the relative speed determined by the first relative speed determination unit 32 and the relative speed determined by the second relative speed determination unit 33, and outputs the determination result. The predetermined relationship may be, for example, the positional relationship shown in Figure 4B where the vehicle 100 is traveling directly alongside the other vehicle 200. That is, it may be a positional relationship where the reference line L, which is a straight line passing from the center C1 of the vehicle 100 to the center C2 of the vehicle 200, is approximately parallel to the left-right direction Y. For example, the notification determination processing unit 34 will make a notification determination based on the relative speed determined by both the first relative speed determination unit 32 and the second relative speed determination unit 33 when the vehicle 100 is traveling directly alongside the other vehicle 200 as shown in Figure 4B, or when the vehicle 100 has overtaken the other vehicle 200 as shown in Figure 4C. The notification determination processing unit 34 may also make a notification determination based on both the relative speed determined by the first relative speed determination unit 32 and the relative speed determined by the second relative speed determination unit 33, regardless of the positional relationship between the vehicle 100 and the target.

[0041] Here, we will explain the detection accuracy of relative velocity when determining the relative velocity of a target based on the difference between the frequency of the transmitted wave and the frequency of the reflected wave, and when determining the relative velocity of a target based on the change in position over time.

[0042] The second relative speed determination unit 33 determines, for example, the relative speed of the target with respect to the vehicle 100, and the radial relative speed calculated from the Doppler frequency centered on the vehicle body center C of the vehicle 100 is expressed by, for example, the following equation (1).

[0043] Vrel = Freq (frequency) × B ... Equation (1) "Vrel" represents the radial relative velocity calculated from the Doppler frequency, and "B" is a value indicating the frequency resolution of the relative velocity of radar device 1.

[0044] Figure 5 is a graph showing the relative velocity calculated from the Doppler frequency, which changes according to the relative position of vehicle 100 and other vehicle 200. The horizontal axis of Figure 5 represents the angle θ (deg), and the vertical axis represents the relative velocity calculated from the Doppler frequency. The solid line in Figure 5 shows the change in the relative velocity calculated from the Doppler frequency with respect to angle θ when the relative velocity V in the longitudinal direction X is relative velocity V1, and the dashed line shows the change in the relative velocity calculated from the Doppler frequency with respect to angle θ when the relative velocity V in the longitudinal direction X is higher than relative velocity V1, which is relative velocity V2. Note that the relative velocities V1 and V2 in Figure 5 remain constant and do not change.

[0045] As shown in Figures 4A to 4C, Figure 5, and Equation (1), even if the relative velocities V1 and V2 in the longitudinal direction X are constant, the relative velocity calculated from the Doppler frequency changes depending on the angle θ. Therefore, when determining the relative velocity by changing the frequency, it is necessary to consider the angle θ and determine the relative velocity V in the longitudinal direction X. However, as shown in Figure 4B, when the angle θ is 90° such that the vehicle 100 and the other vehicle 200 are positioned directly beside each other, the relative velocities V1 and V2 become A, which is the same value as the relative velocity calculated from the Doppler frequency, as shown in Figure 5. In other words, the difference between relative velocities V1 and V2 cannot be detected from the relative velocity calculated from the Doppler frequency. Furthermore, even when the angle is around 90°, the difference is extremely small, indicating that the relative velocity cannot be accurately detected.

[0046] On the other hand, as shown in Figure 4C, when vehicle 100 overtakes vehicle 200 and the angle θ differs significantly from 90°, the difference in relative speed calculated from the Doppler frequency between relative speeds V1 and V2 becomes large, as shown in Figure 5, and the accuracy of detecting relative speed due to the Doppler effect improves. However, when determining relative speed by the time change of relative position, the change in the nearest distance to the centroid of the point cloud on the side of vehicle 200 is small from the time vehicle 100 pulls up alongside vehicle 200 until it overtakes vehicle 200, and detection errors of the centroid of the point cloud are likely to occur. As a result, the relative speed may be calculated to be slower than the actual value, and an alarm may be triggered even at speeds that would not be subject to notification.

[0047] In contrast, in this embodiment, notification determination is performed using both the relative speed determined by the difference between the frequency of the transmitted wave and the frequency of the received wave, and the relative speed determined based on the time change in the relative position of the target between the vehicle 100 and the other vehicle 200. This allows notification determination to be performed by considering the relative speed determined based on the time change in relative position when the angle θ between the vehicle 100 and the target is around 90°, where there is no change in the frequency of the transmitted wave and the reflected wave, and considering the relative speed determined based on the difference in frequency between the transmitted wave and the reflected wave when the detection error of the centroid of the point cloud becomes large. In other words, if the detection accuracy of the relative speed due to the time change of the target's position is low, the detection result of the relative speed using the Doppler effect is considered, and conversely, if the detection accuracy of the relative speed using the method utilizing the Doppler effect is low, the detection result of the relative speed due to the time change of relative position is considered, and the relative speed can be determined. Therefore, the relative speed of the target can be accurately grasped, and the target to be notified can be determined more accurately.

[0048] Furthermore, as shown in Figure 5, the relative speed calculated from the Doppler frequency, which is the relative speed in the radial direction of the vehicle 100, decreases as the angle θ increases, even if the relative speed in the longitudinal direction X remains constant. In this embodiment, the threshold setting unit 35 adjusts the second threshold value for the relative speed obtained by the second relative speed identification unit 33 based on the positional relationship between the vehicle 100 and the target acquired by the detection processing unit 31. For example, as shown in Figure 5, the threshold setting unit 35 adjusts the second threshold value so that it decreases as the angle θ increases.

[0049] Next, an example of the flow of the notification determination process performed by the radar device 1 according to this embodiment will be described with reference to Figure 6. Figure 6 is a flowchart showing an example of the flow of the notification determination process by the radar device 1.

[0050] As shown in Figure 6, in step S11, the detection processing unit 31 acquires information on transmitted and reflected waves from the antenna unit 20 and analyzes it to detect other vehicles 200 within the detectable range Z.

[0051] In step S12, the detection processing unit 31 identifies the position of the target based on the transmitted and reflected waves acquired in step S11. At this time, the detection processing unit 31 identifies the positions of other targets at multiple points in time.

[0052] In step S13, the first relative speed determination unit 32 calculates the time change in the target's position from the information on the multiple positions of the other vehicles 200 obtained in step S12, and determines the relative speed of the target based on the time change in the positions of the other vehicles 200.

[0053] In step S14, the second relative speed determination unit 33 determines the relative speed of the target based on the difference between the frequency of the transmitted wave and the frequency of the reflected wave acquired in step S11. At this time, the second relative speed determination unit 33 determines the relative speed in the radial direction centered on the vehicle 100.

[0054] In step S15, the threshold setting unit 15 sets a first threshold for the relative speed identified in step S13 and a second threshold for the relative speed identified in step S14. Specifically, the threshold setting unit 15 sets a predetermined fixed value as the first threshold and sets the second threshold based on the positional relationship between the vehicle 100 and the target acquired in step S12.

[0055] In step S16, the notification determination processing unit 34 determines whether or not the target is subject to notification. For example, if the relative velocity identified in step S13 is less than or equal to the first threshold set in step S15, and the relative velocity identified in step S14 is less than or equal to the second threshold set in step S15, the notification determination processing unit 34 determines that the target is subject to notification; otherwise, it determines that the target is not subject to notification. If the notification determination processing unit 34 determines that the target is subject to notification (step S16; Yes), it proceeds to step S17. On the other hand, if the notification determination processing unit 34 determines that the target is not subject to notification (step S16; No), it terminates the processing executed by the radar control unit 10 in the notification determination process.

[0056] In step S17, the notification determination processing unit 34 transmits the determination result that the other vehicle 200 determined in step S16 is a target for notification to the ECU2. As a result, a notification command signal is transmitted from the ECU2 to the notification device 3, and the user is notified of the presence of targets around the vehicle 100. After the processing in step S17, the notification determination processing executed by the radar control unit 10 is completed.

[0057] According to the embodiments described above, the following effects are achieved.

[0058] The radar device 1 according to this embodiment is mounted on the vehicle 100 and transmits a transmission wave to other vehicles 200 present around the vehicle 100 and receives reflected waves formed by reflection by the other vehicles 200. The radar device 1 comprises: a first relative speed determination unit 32 that determines the relative speed of a target with respect to the vehicle 100 based on the time change in the position of the target determined from the transmitted wave and the reflected wave; a second relative speed determination unit 33 that determines the relative speed of the target with respect to the vehicle 100 based on the difference between the frequency of the transmitted wave and the frequency of the reflected wave; and a notification determination processing unit 34 that determines whether or not to make the target a target for notification based on the relative speed determined by the first relative speed determination unit 32 and the second relative speed determination unit 33, and outputs the determination result.

[0059] This allows for the combined use of relative velocities determined by two different methods: one based on the time change of the target's position and the other based on the frequency difference between the transmitted and reflected waves. This makes it possible to accurately determine the relative velocity of a target regardless of its positional relationship to the target. Specifically, when the accuracy of detecting relative velocity based on the time change of position is low, the detection result using the Doppler effect is considered. Conversely, when the accuracy of detecting relative velocity using the Doppler effect is low, the detection result using the time change of position is considered to determine the relative velocity. Therefore, it becomes possible to accurately determine the relative velocity of a target and accurately determine whether the target is the target of notification.

[0060] Furthermore, in the radar device 1 according to this embodiment, when the positional relationship between the vehicle 100 and the target reaches a predetermined relationship, the notification determination processing unit 34 determines whether or not to make the vehicle 100 a target for notification based on the relative speed determined by the first relative speed determination unit 32 and the second relative speed determination unit 33, and outputs the determination result.

[0061] This allows for adjustment of the timing of using both relative velocity based on the time change of the target's position and relative velocity utilizing the Doppler effect, depending on the positional relationship between the vehicle 100 and the target. Therefore, it becomes possible to accurately determine whether something is a target for notification while reducing the processing load.

[0062] Furthermore, in the radar device 1 according to this embodiment, the notification determination processing unit 34 determines that a target is to be notified if both the relative speed determined by the first relative speed determination unit 32 and the relative speed determined by the second relative speed determination unit 33 are below a predetermined threshold.

[0063] This allows for a simple process to determine whether a target is a signal.

[0064] Furthermore, in the radar device 1 according to this embodiment, the relative speed identified by the second relative speed identification unit 33 is the relative speed in the radial direction centered on the vehicle 100, and the threshold value for the relative speed in the radial direction changes according to the positional relationship with the target.

[0065] This allows for the determination of the relative velocity in the radial direction, eliminating the need to convert the relative velocity determined from the frequency difference between the transmitted and reflected waves into the relative velocity V in the longitudinal direction X, thereby reducing the processing load. Furthermore, since the threshold value for the relative velocity in the radial direction changes according to the positional relationship with the target, the relative velocity can be determined more accurately based on the frequency difference between the transmitted and reflected waves while reducing the processing load.

[0066] The notification determination method according to this embodiment is a notification determination method performed by a radar device 1 mounted on the vehicle 100, which transmits a transmission wave to other vehicles 200 present around the vehicle 100 and receives a reflected wave formed when the transmission wave is reflected by the other vehicles 200, and includes: a first relative speed determination step of determining the relative speed of a target with respect to the vehicle 100 based on the time change in the position of the target determined from the transmission wave and the reflected wave; a second relative speed determination step of determining the relative speed of the target with respect to the vehicle 100 based on the difference between the frequency of the transmission wave and the frequency of the reflected wave; and a notification determination processing step of determining whether or not to make the target a target for notification based on the relative speed determined in the first relative speed determination step and the second relative speed determination step, and outputting the determination result.

[0067] This allows for the combined use of relative velocities determined by two different methods: one based on the time change of the target's position and the other based on the frequency difference between the transmitted and reflected waves. This makes it possible to accurately determine the relative velocity of a target regardless of its positional relationship to the target. Specifically, when the accuracy of detecting relative velocity based on the time change of relative position is low, the detection result using the Doppler effect is considered. Conversely, when the accuracy of detecting relative velocity using the Doppler effect is low, the detection result using the time change of relative position is considered to determine the relative velocity. Therefore, it becomes possible to accurately determine the relative velocity of a target and accurately determine whether the target is the target of notification.

[0068] The program according to this embodiment causes the computer of a radar device 1, which is mounted on the vehicle 100 and transmits a transmission wave to other vehicles 200 present around the vehicle 100, and receives reflected waves formed when the transmission wave is reflected by the other vehicles 200, to execute a first relative speed determination function that determines the relative speed of a target with respect to the vehicle 100 based on the time change in the position of the target determined from the transmission wave and the reflected wave; a second relative speed determination function that determines the relative speed of the target with respect to the vehicle 100 based on the difference between the frequency of the transmission wave and the frequency of the reflected wave; and a notification determination processing function that determines whether or not to make the target a target for notification based on the relative speed determined by the first relative speed determination function and the second relative speed determination function, and outputs the determination result.

[0069] This allows for the combined use of relative velocities determined by two different methods: one based on the time change of the target's position and the other based on the frequency difference between the transmitted and reflected waves. This makes it possible to accurately determine the relative velocity of a target regardless of its positional relationship to the target. Specifically, when the accuracy of detecting relative velocity based on the time change of relative position is low, the detection result using the Doppler effect is considered. Conversely, when the accuracy of detecting relative velocity using the Doppler effect is low, the detection result using the time change of relative position is considered to determine the relative velocity. Therefore, it becomes possible to accurately determine the relative velocity of a target and accurately determine whether the target is the target of notification.

[0070] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified as appropriate.

[0071] In the above embodiment, the second relative speed determination unit 33 determined the relative speed of the vehicle 100 in the radial direction, but it may also determine the relative speed in the longitudinal direction X.

[0072] Furthermore, the series of processes in the above-described embodiments and modifications can be executed by hardware or by software. When the series of processes are executed by software, the programs constituting the software are installed on a computer or the like from a network or recording medium. The computer may be a computer built into dedicated hardware. Alternatively, the computer may be a computer capable of performing various functions by installing various programs, such as a general-purpose personal computer. [Explanation of symbols]

[0073] 1. Radar equipment 32 First relative velocity determination unit 33 Second relative velocity specification unit 34 Notification and Judgment Processing Unit 100 Self-vehicle (first moving object) 200 Other vehicles (second mobile unit)

Claims

1. A radar device mounted on a first mobile body, which transmits a transmission wave to a second mobile body located around the first mobile body, and receives a reflected wave formed by the reflection of the transmission wave by the second mobile body, A first relative velocity determination unit determines the relative velocity of the target with respect to the first moving body based on the time change in the position of the target determined from the transmitted wave and the reflected wave, A second relative velocity determination unit determines the relative velocity of the target with respect to the first moving body based on the difference between the frequency of the transmitted wave and the frequency of the reflected wave, The system includes a notification determination processing unit that determines whether or not to make the target subject to notification based on the relative speed determined by the first relative speed determination unit and the second relative speed determination unit, and outputs the determination result, The notification determination processing unit determines that the target is a radar device to be notified when the first moving body is in a positional relationship with the second moving body, and both the relative speed determined by the first relative speed determination unit and the relative speed determined by the second relative speed determination unit are below a predetermined threshold.

2. The relative velocity determined by the second relative velocity determination unit is the radial relative velocity centered on the first moving body. The radar device according to claim 1, wherein the threshold value for the relative velocity in the radial direction changes according to the positional relationship with the target.

3. A notification determination method performed by a radar device mounted on a first mobile body, which transmits a transmission wave to a second mobile body located around the first mobile body, and receives a reflected wave formed when the transmission wave is reflected by the second mobile body, A first relative velocity determination step, in which the relative velocity of the target with respect to the first moving body is determined based on the time change in the position of the target determined from the transmitted wave and the reflected wave, A second relative velocity determination step, in which the relative velocity of the target with respect to the first moving body is determined based on the difference between the frequency of the transmitted wave and the frequency of the reflected wave, The process includes a notification determination step which determines whether or not the target is subject to notification based on the relative speeds determined in the first relative speed determination step and the second relative speed determination step, and outputs the determination result, In the notification determination process step, the notification determination method determines that the target is to be notified when the first moving body is in a positional relationship with the second moving body and both the relative speed determined in the first relative speed determination step and the relative speed determined in the second relative speed determination step are below a predetermined threshold.

4. A radar device computer mounted on a first mobile body transmits a transmission wave to a second mobile body located around the first mobile body, and receives a reflected wave formed when the transmission wave is reflected by the second mobile body, A first relative velocity determination function that determines the relative velocity of the target with respect to the first moving body based on the time change in the position of the target determined from the transmitted wave and the reflected wave, A second relative velocity determination function that determines the relative velocity of the target with respect to the first moving body based on the difference between the frequency of the transmitted wave and the frequency of the reflected wave, A program that executes a notification determination processing function which determines whether or not to make the target subject to notification based on the relative speed determined by the first relative speed determination function and the second relative speed determination function, and outputs the determination result. The notification determination processing function is a program that, when the first moving body is in a positional relationship with the second moving body, determines that the target should be notified if both the relative speed determined by the first relative speed determination function and the relative speed determined by the second relative speed determination function are below a predetermined threshold.

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