JP7670724B2 - Vehicle radar system and vehicle - Google Patents

Description

The present disclosure relates to a vehicle radar system and a vehicle equipped with the vehicle radar system.

A vehicle capable of running in autonomous driving mode is equipped with multiple sensors that acquire data indicative of the vehicle's surrounding environment, such as millimeter-wave radar, cameras, and LiDAR units. For example, in the disclosure of Patent Document 1, the vehicle is equipped with a long-range millimeter-wave radar for monitoring the area ahead of the vehicle and a short-range millimeter-wave radar for monitoring the areas to the sides of the vehicle.

Japanese Patent Application Publication No. 2008-152387

In general, to detect the surrounding environment in the front side area of the vehicle (for example, the left front area or the right front area), a short-range millimeter-wave radar is mounted near the corner of the vehicle. Specifically, to detect the surrounding environment in the left front area of the vehicle, a short-range millimeter-wave radar is mounted near the left front corner of the vehicle. Furthermore, to detect the surrounding environment in the right front area of the vehicle, another short-range millimeter-wave radar is mounted near the right front corner of the vehicle. Furthermore, to detect the surrounding environment in the front area of the vehicle, a long-range millimeter-wave radar is mounted in the center of the vehicle in the left-right direction. In this way, in order to detect the surrounding environment in the front side area and the front area of the vehicle, multiple millimeter-wave radars are mounted on the front part of the vehicle. On the other hand, the more millimeter-wave radars are mounted on the vehicle, the more space needs to be secured in the vehicle to mount the millimeter-wave radars. For this reason, it is originally desirable to reduce the number of millimeter-wave radars mounted on the vehicle as much as possible. Thus, there is room for consideration of a radar system that can detect the surrounding environment in the front side and forward areas of the vehicle while reducing the number of millimeter wave radars mounted on the vehicle.

The present disclosure aims to provide a vehicle radar system and a vehicle capable of detecting the surrounding environment in the forward and lateral areas of the vehicle while reducing the number of radars installed in the vehicle.

A radar system for a vehicle mounted on a vehicle according to an embodiment of the present disclosure includes:
a first transmitting antenna configured to emit a first radio wave toward an exterior of the vehicle;
a second transmitting antenna configured to emit a second radio wave toward an exterior of the vehicle;
a receiving antenna configured to receive the first radio wave reflected by an object present in a front side area of the vehicle and to receive the second radio wave reflected by an object present in a front area of the vehicle;
a signal processing circuit configured to generate first radar data indicating a surrounding environment in a front side area of the vehicle based on the received first radio wave, and to generate second radar data indicating a surrounding environment in a front area of the vehicle based on the received second radio wave;
The radar is provided with:
The first transmitting antenna, the second transmitting antenna, and the receiving antenna are formed on the same antenna substrate.

According to the above configuration, first radar data indicating the surrounding environment in the front side area of the vehicle can be generated based on the first radio wave emitted from the first transmitting antenna, and second radar data indicating the surrounding environment in the front area of the vehicle can be generated based on the second radio wave emitted from the second transmitting antenna. Furthermore, the first transmitting antenna, the second transmitting antenna, and the receiving antenna are formed on the same antenna substrate. In this way, it is possible to detect the surrounding environment in the front side area and the front area of the vehicle using one radar. Therefore, it is possible to provide a vehicle radar system that can detect the surrounding environment in the front side area and the front area of the vehicle while reducing the number of radars mounted on the vehicle.

A vehicle equipped with the above-mentioned vehicle radar system may also be provided.

Based on the above, it is possible to provide a vehicle radar system and a vehicle capable of detecting the surrounding environment in the front lateral and forward areas of the vehicle while reducing the number of radars mounted on the vehicle.

The present disclosure makes it possible to provide a vehicle radar system capable of detecting the surrounding environment in the forward and lateral areas of the vehicle while reducing the number of radars mounted on the vehicle.

1 is a schematic diagram illustrating an example of a vehicle radar system. FIG. 2 is a schematic diagram illustrating a first field of view of a radar associated with a first wave and a second field of view of a radar associated with a second wave. FIG. 2 is a block diagram showing a part of a configuration of a vehicle system. FIG. 2 is a block diagram showing the configuration of a radar. 2 is a front view showing an example of a first transmitting antenna, a second transmitting antenna, and a receiving antenna formed on an antenna substrate; FIG. FIG. 4 is a front view showing the first reflector. FIG. 4 is a front view showing a second reflector. 10 is a flowchart illustrating a process of generating first radar data and second radar data. 10 is a flowchart illustrating a process for setting a relationship between a first update rate of the first radar data and a second update rate of the second radar data in accordance with a speed of a vehicle.

Hereinafter, an embodiment of the present disclosure (hereinafter, simply referred to as the "present embodiment") will be described with reference to the drawings. For the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

In addition, in the description of this embodiment, for convenience of explanation, the "left-right direction," "front-rear direction," and "up-down direction" of the vehicle 1 may be referred to as appropriate. These directions are relative directions set for the vehicle 1 shown in FIG. 2. Here, the "left-right direction" is a direction including the "left direction" and the "right direction." The "front-rear direction" is a direction including the "forward direction" and the "rearward direction." Note that although the up-down direction is not shown in FIG. 2, the up-down direction is a direction perpendicular to the left-right direction and the front-rear direction. Furthermore, the vertical direction D2 (see FIG. 5) of the radar 2 mounted on the vehicle 1 is parallel to the up-down direction of the vehicle 1. Also, the horizontal direction D1 of the radar 2 is a direction perpendicular to the vertical direction D2 of the radar 2.

First, a vehicle radar system 10 (hereinafter simply referred to as radar system 10) according to this embodiment will be described below with reference to Figure 1. Figure 1 is a schematic diagram showing an example of a radar system 10. As shown in Figure 1, the radar system 10 is mounted on a vehicle 1, and includes a radar 2, a first reflector 3, and a second reflector 5. The radar system 10 further includes a radar control unit 6 shown in Figure 4. Although the radar control unit 6 is not shown in Figure 1, the location of the radar control unit 6 is not particularly limited.

The radar 2, the first reflector 3, and the second reflector 5 are covered by the front bumper 8 of the vehicle 1, and are disposed in an internal space S surrounded by the front bumper 8 and a vehicle body (not shown). In other words, the radar system 10 is concealed from the outside of the vehicle 1 by the front bumper 8.

The radar 2 is, for example, a millimeter wave radar or a microwave radar. The radar 2 is configured to acquire radar data indicating the surrounding environment of the vehicle 1 by emitting radio waves toward the front of the vehicle 1. In particular, the radar 2 functions as both a long-range radar (forward monitoring radar) and a short-range radar (periphery monitoring radar). When the radar 2 functions as a short-range radar, the radar 2 emits a first radio wave toward an object present in the left front area (an example of a front side area) of the vehicle 1, and acquires first radar data indicating information related to the object (e.g., the distance, direction, and relative speed of the object) in response to receiving the first radio wave reflected by the object. When the radar 2 functions as a long-range radar, the radar 2 emits a second radio wave toward an object present in the front area of the vehicle 1 via the first reflector 3 and the second reflector 5, and acquires second radar data indicating information related to the object in response to receiving the second radio wave reflected by the object. The radar 2 is fixed by, for example, a bracket (not shown) attached to the vehicle body. The first radio wave and the second radio wave may be, for example, millimeter waves in the 77 GHz band.

(Radar Configuration)
Next, the configuration of the radar 2 will be described in detail with reference to Figures 1, 4, and 5. Figure 4 is a block diagram showing the configuration of the radar 2. Figure 5 is a front view showing an example of a first transmitting antenna 25, a second transmitting antenna 26, and a receiving antenna 27 formed on the front surface 20a of the antenna substrate 20.

1, the radar 2 includes an antenna board 20, a first transmitting antenna 25, a second transmitting antenna 26, a receiving antenna 27, and a radome 21 that houses the antenna board 20. Furthermore, as shown in FIG. 4, the radar 2 includes a transmitting RF (radio frequency) circuit 24, a receiving RF circuit 23, and a signal processing circuit unit 22.

As shown in FIG. 5, the antenna substrate 20 is configured as a single antenna substrate. A first transmitting antenna 25, a second transmitting antenna 26, and a receiving antenna 27 are formed on the surface 20a of the antenna substrate 20. The first transmitting antenna 25 is configured to emit a first radio wave toward the outside of the vehicle 1. In particular, the first transmitting antenna 25 is configured to emit a first radio wave toward an object such as another vehicle present in the left front area (an example of a front side area) of the vehicle 1. As shown in FIG. 5, the first transmitting antenna 25 has a plurality of first transmitting antenna elements 125 (patch antenna elements) arranged in the horizontal direction D1 and the vertical direction D2 of the radar 2. In the example shown in FIG. 5, the first transmitting antenna 25 is composed of a plurality of first transmitting antenna elements 125 arranged in 7 rows and 3 columns. That is, three first transmitting antenna elements 125 are arranged in the horizontal direction D1, and seven first transmitting antenna elements 125 are arranged in the vertical direction D2. A first radio wave is emitted from the first transmitting antenna 25 as a composite radio wave of the radio waves emitted from each of the first transmitting antenna elements 125. As already described, the vertical direction D2 of the radar 2 is parallel to the up-down direction of the vehicle 1.

1, the first field of view V1 in the horizontal direction D1 of the radar 2 associated with the first radio wave emitted from the first transmitting antenna 25 is, for example, within a range of ±40° to ±75°. The first field of view V1 in the vertical direction D2 associated with the first radio wave is, for example, within a range of ±2° to ±5°. The detection distance of the radar 2 associated with the first radio wave is, for example, within a range of 70 m to 100 m.

The second transmitting antenna 26 is configured to emit the second radio wave toward the outside of the vehicle 1 through the first reflector 3 and the second reflector 5. In particular, the second transmitting antenna 26 is configured to emit the second radio wave toward an object such as another vehicle present in the forward area of the vehicle 1. As shown in FIG. 5, the second transmitting antenna 26 has a plurality of second transmitting antenna elements 126 (patch antenna elements) arranged in the horizontal direction D1 and vertical direction D2 of the radar 2. In the example shown in FIG. 5, the second transmitting antenna 26 is composed of a plurality of second transmitting antenna elements 126 arranged in 7 rows x 5 columns. That is, five second transmitting antenna elements 126 are arranged in the horizontal direction D1, and seven second transmitting antenna elements 126 are arranged in the vertical direction D2. The second radio wave is emitted from the second transmitting antenna 26 as a composite radio wave of the radio waves emitted from each second transmitting antenna element 126.

1, the second field of view V2 in the horizontal direction D1 of the radar 2 associated with the second radio wave emitted from the second transmitting antenna 26 is, for example, within a range of ±5° to ±10°. The second field of view V2 in the vertical direction D2 associated with the second radio wave is, for example, within a range of ±2° to ±5°. The detection distance of the radar 2 associated with the second radio wave is, for example, 200 m or more (specifically, within a range of 200 m to 300 m). In this embodiment, since the number of the first transmitting antenna elements 125 arranged in the horizontal direction D1 is smaller than the number of the second transmitting antenna elements 126 arranged in the horizontal direction D1, the first field of view V1 in the horizontal direction D1 is larger than the second field of view V2 in the horizontal direction D1. Furthermore, the detection distance of the radar 2 associated with the second radio wave is larger than the detection distance of the radar 2 associated with the first radio wave. In this way, the first transmitting antenna 25 functions as a wide-angle transmitting antenna, and the second transmitting antenna 26 functions as a narrow-angle transmitting antenna.

The receiving antenna 27 is configured to receive radio waves reflected by objects such as other vehicles outside the vehicle 1. In particular, the receiving antenna 27 is configured to receive a first radio wave reflected by an object present in the left front area of the vehicle 1, and a second radio wave reflected by an object present in the front area of the vehicle 1. In this embodiment, the receiving antenna 27 is configured as a single receiving antenna configured to receive both the reflected wave of the first radio wave emitted from the first transmitting antenna 25 and the reflected wave of the second radio wave emitted from the second transmitting antenna 26. In this embodiment, since the receiving antenna 27 is configured as a single receiving antenna, it is possible to suppress an increase in the external size of the radar 2. In addition, in this embodiment, the frequency of the first radio wave and the frequency of the second radio wave are the same. Therefore, in order to avoid interference between the first radio wave and the second radio wave, the receiving antenna 27 is configured to receive the first radio wave and the second radio wave at different times. In other words, the timing at which the first transmitting antenna 25 emits the first radio wave and the timing at which the second transmitting antenna 26 emits the second radio wave are different from each other (this will be described later).

As shown in FIG. 5, the receiving antenna 27 is disposed between the first transmitting antenna 25 and the second transmitting antenna 26 in the horizontal direction D1. The receiving antenna 27 has a plurality of receiving antenna elements 127 (patch antenna elements) arranged in the horizontal direction D1 and the vertical direction D2 of the radar 2. In the example shown in FIG. 5, the receiving antenna 27 is composed of a plurality of receiving antenna elements 127 arranged in 7 rows and 5 columns. That is, five receiving antenna elements 127 are arranged in the horizontal direction D1, and seven receiving antenna elements 127 are arranged in the vertical direction D2. Each receiving antenna element 127 is configured to receive a reflected wave of the first radio wave and a reflected wave of the second radio wave. In this respect, when the receiving antenna 27 receives a reflected wave of the first radio wave, only the high-frequency signals output from the receiving antenna elements 127 of 7 rows and 3 columns present in the area 127a surrounded by a dashed line may be used. On the other hand, when the receiving antenna 27 receives a reflected wave of the second radio wave, the high-frequency signals output from all of the receiving antenna elements 127 may be used.

4, the transmitting RF circuit 24, the receiving RF circuit 23, and the signal processing circuit unit 22 are configured as a monolithic microwave integrated circuit (MMIC). The MMIC may be mounted, for example, on the back surface of the antenna substrate 20 located opposite the front surface 20a of the antenna substrate 20. The transmitting RF circuit 24 is electrically connected to the first transmitting antenna 25 and the second transmitting antenna 26, and is configured to supply high-frequency signals to the first transmitting antenna 25 and the second transmitting antenna 26. The transmitting RF circuit 24 includes a high-frequency generating circuit that generates a high-frequency signal, a plurality of phase shifters that adjust the phase of the high-frequency signal, and a plurality of amplifiers. When the radar 2 is a radar that employs the FMCW method, the high-frequency generating circuit generates a chirp signal (FMCW signal) whose frequency changes linearly with time. When the radar 2 emits the first radio wave, the transmitting RF circuit 24 supplies a high-frequency signal to the first transmitting antenna 25. On the other hand, when the radar 2 emits the second radio wave, the transmitting RF circuit 24 supplies a high-frequency signal to the second transmitting antenna 26 .

In addition, in this embodiment, as shown in FIG. 1, the emission direction of the second radio wave emitted from the second transmitting antenna 26 is inclined with respect to the detection axis A1 of the radar 2. Here, the emission direction of the second radio wave corresponds to the emission direction of the beam center axis of the second radio wave, which is a composite radio wave of the radio waves emitted from each second transmitting antenna element 126. The detection axis A1 of the radar 2 is an axis perpendicular to the surface 20a of the antenna substrate 20. At this point, since the detection axis A1 faces the left front direction of the vehicle 1, the emission direction of the first radio wave emitted from the first transmitting antenna 25 also faces the left front direction. On the other hand, the emission direction of the second radio wave is inclined with respect to the detection axis A1 so that the emission direction of the second radio wave faces the forward direction.

In this embodiment, each phase shifter provided in the transmitting RF circuit 24 controls the phase of the high frequency signal (TX signal) supplied to the second transmitting antenna 26, thereby making it possible to control the emission direction of the second radio wave. In this respect, the first phase shifter provided in the transmitting RF circuit 24 adjusts the phase of the TX signal input to the second transmitting antenna element group 126a consisting of seven second transmitting antenna elements 126 arranged in the first row (see FIG. 5). The second phase shifter adjusts the phase of the TX signal input to the second transmitting antenna element group 126b consisting of seven second transmitting antenna elements 126 arranged in the second row. The third phase shifter adjusts the phase of the TX signal input to the second transmitting antenna element group 126c consisting of seven second transmitting antenna elements 126 arranged in the third row. The fourth phase shifter adjusts the phase of the TX signal input to the second transmitting antenna element group 126d consisting of seven second transmitting antenna elements 126 arranged in the fourth row. The fifth phase shifter adjusts the phase of the TX signal input to the second transmitting antenna element group 126e, which is composed of seven second transmitting antenna elements 126 arranged in a fifth row. In this way, by adjusting the phase of the TX signal input to each of the second transmitting antenna element groups 126a to 126e, the emission direction of the second radio wave in the horizontal direction D1 can be tilted with respect to the detection axis A1. As a result, the second transmitting antenna 26 can emit the second radio wave in the forward direction.

The receiving RF circuit 23 is electrically connected to the receiving antenna 27 and configured to receive a weak high-frequency signal from the receiving antenna 27. The receiving RF circuit 23 includes an amplifier, a mixer, a bandpass filter, an AD converter, and a filter circuit. The amplifier is configured to amplify the weak high-frequency signal output from the receiving antenna 27. The mixer generates an intermediate frequency (IF) signal by mixing the high-frequency signal (RX signal) output from the amplifier and the high-frequency signal (TX signal) output from the high-frequency generating circuit. The AD converter is configured to convert the IF signal that has passed through the bandpass filter from an analog signal to a digital signal. The digital signal is transmitted to the signal processing circuit unit 22 via the filter circuit.

The signal processing circuit unit 22 is configured to control the transmitting RF circuit 24 and the receiving RF circuit 23 in response to a control signal from the radar control unit 6. Furthermore, the signal processing circuit unit 22 is configured to generate radar data (first radar data and second radar data) by performing signal processing (e.g., fast Fourier transform processing) on the digital signal output from the receiving RF circuit 23, and then transmit the generated radar data to the radar control unit 6. The signal processing circuit unit 22 includes, for example, a DSP (Digital Signal Processor) and a microcomputer composed of a processor and a memory.

When the radar 2 emits the first radio wave, the signal processing circuit unit 22 generates first radar data indicating the surrounding environment in the left front area of the vehicle 1 based on a digital signal related to the reflected wave of the first radio wave output from the receiving RF circuit 23. On the other hand, when the radar 2 emits the second radio wave, the signal processing circuit unit 22 generates second radar data indicating the surrounding environment in the front area of the vehicle 1 based on a digital signal related to the reflected wave of the second radio wave output from the receiving RF circuit 23. In this respect, the signal processing circuit unit 22 is configured to generate the first radar data and the second radar data at different timings. In particular, the signal processing circuit unit 22 is configured to generate the first radar data at a first update rate and generate the second radar data at a second update rate different from the first update rate.

The radar control unit 6 is configured to control the operation of the radar 2. The radar control unit 6 is configured, for example, by an electronic control unit (ECU). The electronic control unit has a microcomputer composed of a processor and a memory. The radar control unit 6 is also configured to change the relationship between the first update rate of the first radar data and the second update rate of the second radar data depending on the speed of the vehicle 1 (details will be described later).

(Configuration of the First Reflector and the Second Reflector)
Next, the first reflector 3 and the second reflector 5 provided in the radar system 10 will be described below with reference to FIGS. 1 and 6B.

First, in this embodiment, the radar 2 is disposed in the internal space S at a position away from the center in the left-right direction of the vehicle 1. In this respect, the radar 2 also functions as a forward monitoring radar for monitoring the area ahead of the vehicle 1, so it is preferable to dispose it in the center in the left-right direction of the vehicle 1. On the other hand, in this embodiment, the path of the radio waves emitted from the radar 2 can be changed by using the first reflector 3 and the second reflector 5 shown in FIG. 1, so there is no need to dispose the radar 2 in the center in the left-right direction. Furthermore, since there is no need to dispose the radar 2 in the center in the left-right direction, the radar 2 can be used as a forward monitoring radar and a periphery monitoring radar.

The first reflector 3 faces the second transmitting antenna 26 of the radar 2 in the longitudinal direction of the vehicle 1, and is configured to reflect the second radio wave emitted from the second transmitting antenna 26 toward the second reflector 5. As shown in FIG. 6A, the first reflector 3 has a first reflector 32 and a first radio wave absorber 30.

The first reflector 32 is configured to reflect the second radio wave emitted from the second transmitting antenna 26 toward the second reflector 5, and is made of, for example, a metal material (gold, silver, copper, iron, etc.). The first reflector 32 has an outer size sufficient to reflect the second radio wave within the second field of view V2 of the second radio wave emitted from the second transmitting antenna 26 toward the second reflector 5. In this regard, the outer size of the first reflector 32 is appropriately determined according to the distance between the radar 2 and the first reflector 3, the horizontal viewing angle of the radar 2 associated with the second radio wave, and the vertical viewing angle of the radar 2 associated with the second radio wave.

The first radio wave absorber 30 is configured to absorb the second radio wave emitted from the second transmitting antenna 26. In particular, the first radio wave absorber 30 is configured to absorb side lobe components, which are radio wave components outside the second field of view V2, of the second radio wave emitted from the second transmitting antenna 26. The first radio wave absorber 30 is provided on the first reflector 32 so as to follow the end of the first reflector 32. In particular, the first radio wave absorber 30 is provided on the first reflector 32 so as to completely surround the outer periphery of the first reflector 32. The first radio wave absorber 30 may be formed, for example, of an inorganic binder and radio wave absorbing particles provided in the inorganic binder. As an example of the radio wave absorbing particles, epsilon-type iron oxide particles or titanium oxide particles may be used. The width dimension of the first radio wave absorber 30 is, for example, about 10 mm.

In this embodiment, the first reflector 3 is disposed outside the first field of view V1 of the radar 2 associated with the first radio wave. Therefore, it is possible to preferably prevent noise from occurring in the first radar data associated with the first radio wave due to a part of the first radio wave being reflected by the first reflector 3. In particular, in this embodiment, the emission direction of the second radio wave can be tilted with respect to the detection axis A1 of the radar 2 through phase control of the TX signal input to the second transmitting antenna 26, so that the first reflector 3 can be disposed outside the first field of view V1 of the radar 2. More specifically, since the second radio wave can be emitted in the forward direction, the first reflector 3 and the radar 2 can be disposed side by side in the front-to-rear direction. As a result, the first reflector 3 is disposed outside the first field of view V1 of the radar 2.

The second reflector 5 is configured to reflect the second radio wave reflected by the first reflector 3 toward the area in front of the vehicle 1. In this respect, the second reflector 5 is arranged so as to overlap with an imaginary plane Ax (see FIG. 2) in the left-right direction. Here, the imaginary plane Ax is an imaginary plane that passes through the center of the vehicle 1 in the left-right direction and is perpendicular to the left-right direction of the vehicle 1. As shown in FIG. 6B, the second reflector 5 has a second reflector 52 and a second radio wave absorber 50.

The second reflector 52 is configured to reflect the second radio wave reflected by the first reflector 32 toward the front of the vehicle 1, and is made of, for example, a metal material (gold, silver, copper, iron, etc.). The second reflector 52 has an outer size that can reflect the radio wave within the second field of view V2 toward the front of the vehicle 1. In this regard, the outer size of the second reflector 52 is appropriately determined according to the distance between the radar 2 and the first reflector 3, the distance between the first reflector 3 and the second reflector 5, the horizontal viewing angle of the radar 2 associated with the second radio wave, and the vertical viewing angle of the radar 2 associated with the second radio wave.

The second radio wave absorber 50 is configured to absorb the second radio wave reflected by the first reflector 32. In particular, the second radio wave absorber 50 is configured to absorb side lobe components, which are radio wave components outside the second field of view V2, of the second radio wave reflected by the first reflector 32. The second radio wave absorber 50 is provided on the second reflector 52 so as to follow the end of the second reflector 52. In particular, the second radio wave absorber 50 is provided on the second reflector 52 so as to completely surround the outer periphery of the second reflector 52. The second radio wave absorber 50 may be made of, for example, the same material as the material constituting the first radio wave absorber 30. The width dimension of the second radio wave absorber 50 is, for example, about 10 mm.

The first reflector 3 and the second reflector 5 are configured to change the path of the second radio wave emitted from the second transmitting antenna 26. In this way, the two reflectors allow the second radio wave emitted from the second transmitting antenna 26 to be emitted from the center in the left-right direction of the vehicle 1. Furthermore, radio waves reflected by an object (e.g., another vehicle) present in the area ahead of the vehicle 1 are reflected by the second reflector 5 and the first reflector 3, and as a result, are incident on the receiving antenna 27.

2, the perimeter monitoring radar that acquires information about the surrounding environment in the right front area of the vehicle 1 may be disposed in the right front lamp 4b disposed on the right front side of the vehicle 1. The perimeter monitoring radar that acquires information about the surrounding environment in the left rear area of the vehicle 1 may be disposed in the left rear lamp 4c disposed on the left rear side of the vehicle 1. The perimeter monitoring radar that acquires information about the surrounding environment in the right rear area of the vehicle 1 may be disposed in the right rear lamp 4d disposed on the right rear side of the vehicle 1. Furthermore, the radar 2 and the first reflector 3 may be disposed in the left front lamp 4a disposed on the left front side of the vehicle 1, rather than in the internal space S.

According to this embodiment, first radar data indicating the surrounding environment in the left front area of the vehicle 1 can be generated based on the first radio wave emitted from the first transmitting antenna 25, and second radar data indicating the surrounding environment in the front area of the vehicle 1 can be generated based on the second radio wave emitted from the second transmitting antenna 26. Furthermore, the first transmitting antenna 25, the second transmitting antenna 26, and the receiving antenna 27 are formed on the same antenna substrate 20. In this way, it is possible to detect the surrounding environment in the left front area and the front area of the vehicle 1 using one radar 2. Therefore, it is possible to provide a radar system 10 that can detect the surrounding environment in the left front area and the front area of the vehicle 1 while reducing the number of radars mounted on the vehicle 1.

In addition, according to this embodiment, the path of the second radio wave emitted from the second transmitting antenna 26 can be changed by the first reflector 3 and the second reflector 5, so that the degree of freedom in the mounting location of the radar 2 can be increased, and the surrounding environment in the left front area and the forward area of the vehicle 1 can be detected using a single radar 2. In particular, even if the radar 2 is not positioned in the center of the vehicle 1 in the left-right direction, the second reflector 5 is positioned in the center of the vehicle 1 in the left-right direction. Therefore, it is possible to emit the second radio wave from the center of the vehicle 1 in the left-right direction toward the forward area of the vehicle 1, so that the degree of freedom in the mounting location of the radar 2 can be increased.

In addition, the radar 2, the first reflector 3, and the second reflector 5 are covered by the front bumper 8, which improves the design of the exterior of the vehicle 1. The front bumper 8 also protects the radar system 10 from impacts from outside the vehicle 1.

(Configuration of vehicle system 100)
Next, a part of the configuration of the vehicle system 100 mounted on the vehicle 1 will be described below with reference to Fig. 3. Fig. 3 is a block diagram showing a part of the configuration of the vehicle system 100. As shown in Fig. 3, the vehicle system 100 includes a vehicle control unit 12, a vehicle speed sensor 13, a radar system 10, an HMI (Human Machine Interface) 14, a GPS (Global Positioning System) 15, and a wireless communication module 16.

The vehicle control unit 12 is configured to control the driving of the vehicle 1. The vehicle control unit 12 is configured, for example, by at least one electronic control unit. The electronic control unit includes a computer system (e.g., a SoC (System on a Chip)) including one or more processors and one or more memories, and an electronic circuit configured of active elements such as transistors and passive elements.

The vehicle speed sensor 13 is configured to detect the speed of the vehicle 1. The vehicle speed sensor 13 is configured to transmit speed data indicating the speed of the vehicle 1 to the vehicle control unit 12. As described above, the radar system 10 includes the radar 2, the radar control unit 6, the first reflector 3, and the second reflector 5 (see FIG. 1). The first radar data and the second radar data acquired by the radar 2 are transmitted to the vehicle control unit 12 via the radar control unit 6. The vehicle control unit 12 identifies the surrounding environment in the left front area of the vehicle 1 based on the received first radar data, and identifies the surrounding environment in the forward area of the vehicle 1 based on the received second radar data.

The HMI 14 is composed of an input unit that accepts input operations from the driver, and an output unit that outputs driving information, etc. to the driver. The input unit includes a steering wheel, an accelerator pedal, a brake pedal, a driving mode changeover switch that switches the driving mode of the vehicle 1, etc. The output unit is a display (e.g., a Head Up Display (HUD), etc.) that displays various driving information. The GPS 15 is configured to acquire current position information of the vehicle 1 and output the acquired current position information to the vehicle control unit 12.

The wireless communication module 16 is configured to receive information about other vehicles in the vicinity from the other vehicles and transmit information about the vehicle 1 to the other vehicles (vehicle-to-vehicle communication). The wireless communication module 16 is also configured to receive infrastructure information from traffic infrastructure facilities such as traffic lights and marker lights and transmit driving information about the vehicle 1 to the traffic infrastructure facilities (road-to-vehicle communication). The wireless communication module 16 is also configured to receive information about pedestrians from mobile terminals such as smartphones carried by pedestrians and transmit driving information about the vehicle 1 to the mobile terminals (pedestrian-to-vehicle communication). The vehicle 1 can also receive specified information from a server on a communication network such as the Internet via the wireless communication module 16.

In this embodiment, a radar 2 is installed as a sensing device that acquires information indicating the surrounding environment of the vehicle 1, while the vehicle system 100 may further include a camera and a LiDAR unit in addition to the radar.

(Generation process of first radar data and second radar data)
Next, the generation process of the first radar data and the second radar data will be described below with reference to FIG. 7. FIG. 7 is a flowchart for explaining the generation process of the first radar data and the second radar data. As shown in FIG. 7, in step S1, the first transmitting antenna 25 of the radar 2 emits a first radio wave toward the outside of the vehicle 1 (particularly, the left front area of the vehicle 1) in response to the input of the TX signal from the transmitting RF circuit 24. Next, the receiving antenna 27 of the radar 2 receives the first radio wave reflected by an object (e.g., another vehicle, etc.) present in the left front area of the vehicle 1 (step S2). After that, the signal processing circuit unit 22 of the radar 2 generates first radar data indicating the surrounding environment in the left front area of the vehicle 1 in response to the reception of a digital signal associated with the first radio wave from the receiving RF circuit 23 (step S3). The first radar data generated by the radar 2 is transmitted to the vehicle control unit 12 via the radar control unit 6.

Then, in step S4, if the radar data to be generated next by the radar 2 is not the second radar data (NO in step S4), the processes of steps S1 to S3 are repeatedly executed. On the other hand, if the radar data to be generated next by the radar 2 is the second radar data (YES in step S4), the radar 2 executes the processes of steps S5 to S7 to generate the second radar data.

In step S5, the second transmitting antenna 26 of the radar 2 emits a second radio wave toward the outside of the vehicle 1 in response to the input of the TX signal from the transmitting RF circuit 24. Specifically, the second radio wave emitted from the second transmitting antenna 26 is emitted toward the front area of the vehicle 1 through the first reflector 3 and the second reflector 5 shown in FIG. 1. Next, the receiving antenna 27 of the radar 2 receives the second radio wave reflected by an object (e.g., another vehicle, etc.) present in the front area of the vehicle 1 (step S6). After that, the signal processing circuit unit 22 of the radar 2 generates second radar data indicating the surrounding environment in the front area of the vehicle 1 in response to receiving a digital signal associated with the second radio wave from the receiving RF circuit 23 (step S7). The second radar data generated by the radar 2 is transmitted to the vehicle control unit 12 via the radar control unit 6.

Then, in step S8, if the radar data next generated by the radar 2 is not the first radar data (NO in step S8), the processes of steps S5 to S7 are repeatedly executed. On the other hand, if the radar data next generated by the radar 2 is the first radar data (YES in step S8), the radar 2 executes the processes of steps S1 to S3.

In this way, the signal processing circuit unit 22 is configured to generate the first radar data and the second radar data at different timings. Therefore, even if the frequencies of the first radio wave and the second radio wave are the same, the first radar data and the second radar data can be generated by a single receiving antenna 27. Furthermore, the signal processing circuit unit 22 is configured to generate the first radar data at a first update rate (Hz) and generate the second radar data at a second update rate (Hz). The first update rate and the second update rate may be the same or different from each other.

When the first update rate of the first radar data and the second update rate of the second radar data are the same, the number of times the first radar data generation process (the process of steps S1 to S3) is performed per second is the same as the number of times the second radar data generation process (the process of steps S5 to S7) is performed per second. For example, when the first update rate and the second update rate are 5 Hz, the number of times the first radar data generation process is performed per second is 5 times. On the other hand, when the first update rate of the first radar data and the second update rate of the second radar data are different from each other, the number of times the first radar data generation process is performed per second is different from each other. For example, when the ratio of the first update rate to the second update rate is 3:1, the radar 2 performs the first radar data generation process three times and then performs the second radar data generation process once.

(Setting process of first update rate and second update rate)
Next, a process for setting the relationship between the first update rate of the first radar data and the second update rate of the second radar data depending on the speed of the vehicle 1 will be described below with reference to Figures 3 and 8. Figure 8 is a flowchart for explaining the process for setting the relationship between the first update rate and the second update rate depending on the speed of the vehicle 1.

As shown in FIG. 8, in step S10, the vehicle control unit 12 (see FIG. 3) acquires data indicating the current speed of the vehicle 1 from the vehicle speed sensor 13 and identifies the current speed of the vehicle 1 (step S10). Next, the radar control unit 6 receives information indicating the current speed of the vehicle 1 from the vehicle control unit 12 and determines whether the current speed of the vehicle 1 is equal to or greater than a threshold speed (step S11). When the radar control unit 6 determines that the current speed of the vehicle 1 is equal to or greater than a threshold speed (e.g., 10 km/h) (YES in step S11), the radar control unit 6 sets the first update rate and the second update rate so that the second update rate of the second radar data is greater than the first update rate of the first radar data (step S12). For example, the radar control unit 6 may set the first update rate and the second update rate so that the ratio of the first update rate to the second update rate is 1:3.

On the other hand, when the radar control unit 6 determines that the current speed of the vehicle 1 is less than a threshold speed (e.g., 10 km/h) (NO in step S11), the radar control unit 6 sets the first update rate and the second update rate so that the first update rate of the first radar data is greater than the second update rate of the second radar data (step S13). For example, the radar control unit 6 may set the first update rate and the second update rate so that the ratio of the first update rate to the second update rate is 3:1.

Then, the radar control unit 6 transmits signals indicating the first update rate and the second update rate to the signal processing circuit unit 22 of the radar 2. In this way, the signal processing circuit unit 22 generates the first radar data and the radar data at different timings based on the first update rate and the second update rate determined by the radar control unit 6.

According to this embodiment, the first update rate is greater than the second update rate or the second update rate is greater than the first update rate depending on the relationship between the speed of the vehicle 1 and the threshold speed. In this way, the update rate of the first radar data and the update rate of the second radar data can be set optimally according to the driving conditions of the vehicle 1. In particular, when the vehicle 1 is driving at a speed less than the threshold speed, the detection of an object present in the left front area of the vehicle 1 is prioritized, so the first update rate is greater than the second update rate. On the other hand, when the vehicle 1 is driving at a speed equal to or greater than the threshold speed, the detection of an object present in the front area of the vehicle 1 is prioritized, so the second update rate is greater than the first update rate.

The radar control unit 6 may receive data indicating the current speed of the vehicle 1 directly from the vehicle speed sensor 13. The threshold speed used in the processing of step S11 may be changed as appropriate depending on the driving conditions of the vehicle 1.

Although an embodiment of the present invention has been described above, it goes without saying that the technical scope of the present invention should not be interpreted as being limited by the description of this embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications of the embodiment are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and its equivalents.

This application incorporates as appropriate the contents disclosed in the Japanese patent application (Patent Application No. 2020-145676) filed on August 31, 2020.

Claims (11)

A radar system for a vehicle mounted on a vehicle,
a first transmitting antenna configured to emit a first radio wave toward an exterior of the vehicle;
a second transmitting antenna configured to emit a second radio wave toward an exterior of the vehicle;
a receiving antenna configured to receive the first radio wave reflected by an object present in a front side area of the vehicle and to receive the second radio wave reflected by an object present in a front area of the vehicle;
a signal processing circuit configured to generate first radar data indicating a surrounding environment in a front side area of the vehicle based on the received first radio wave, and to generate second radar data indicating a surrounding environment in a front area of the vehicle based on the received second radio wave;
A radar comprising :
A radar control unit configured to control the operation of the radar;
Equipped with
the first transmitting antenna, the second transmitting antenna, and the receiving antenna are formed on a same antenna substrate,
the signal processing circuit unit is configured to generate the first radar data and the second radar data at different timings,
the signal processing circuit generates the first radar data at a first update rate and generates the second radar data at a second update rate different from the first update rate;
The radar control unit is configured to change a relationship between the first update rate and the second update rate depending on a speed of the vehicle . The first transmitting antenna has a plurality of first transmitting antenna elements arranged in a horizontal direction and a vertical direction of the radar,
the second transmitting antenna has a plurality of second transmitting antenna elements arranged in a horizontal direction and a vertical direction of the radar,
the number of the first transmitting antenna elements arranged in the horizontal direction is less than the number of the second transmitting antenna elements arranged in the horizontal direction,
a first field of view of the radar associated with the first radio wave is larger than a second field of view of the radar associated with the second radio wave in the horizontal direction;
The vehicle radar system according to claim 1 , wherein a detection range of the radar associated with the second radio wave is greater than a detection range of the radar associated with the first radio wave. The frequency of the first radio wave and the frequency of the second radio wave are the same,
3. The radar system for a vehicle according to claim 1, wherein the receiving antenna is a single receiving antenna configured to receive both the first radio wave and the second radio wave. The radar control unit includes:
setting the first update rate and the second update rate such that the first update rate is greater than the second update rate when the speed of the vehicle is less than a threshold speed;
2. The radar system for a vehicle according to claim 1 , wherein the first update rate and the second update rate are set such that the second update rate is greater than the first update rate when the speed of the vehicle is equal to or greater than the threshold speed. a first reflector facing the second transmitting antenna and configured to reflect the second radio wave emitted from the second transmitting antenna;
5. The radar system for a vehicle according to claim 1, further comprising: a second reflector configured to reflect the second radio wave reflected by the first reflector toward a forward area of the vehicle. 6. The vehicle radar system of claim 5 , wherein the first reflector is disposed outside a first field of view of the radar associated with the first radio wave. The vehicle radar system according to claim 6 , wherein the emission direction of the second radio wave is inclined with respect to a detection axis of the radar that is perpendicular to a surface of the antenna substrate. The second reflector is disposed in the center in the left-right direction of the vehicle.
A radar system for a vehicle according to any one of claims 5 to 7 . The radar system for a vehicle according to claim 5 , wherein the radar, the first reflector, and the second reflector are covered by a front bumper of the vehicle. The first reflector is
a first reflector configured to reflect the second radio wave emitted from the second transmitting antenna;
a first radio wave absorber provided on the first reflector along an end portion of the first reflector and configured to absorb the second radio wave emitted from the second transmitting antenna;
The second reflector is
A second reflector configured to reflect the second radio wave reflected by the first reflector toward a front of the vehicle;
10. The radar system for a vehicle according to claim 5, further comprising: a second radio wave absorber provided on the second reflector so as to extend along an end of the second reflector and configured to absorb the second radio wave reflected by the first reflector. A vehicle comprising the radar system for vehicles according to any one of claims 1 to 10 .

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