JP7845129B2 - radar equipment - Google Patents

Description

This disclosure relates to radar equipment.

Patent Document 1 describes a system in which, for each modulation used in the transmitted signal, the antenna array of the transmitting antenna and/or the antenna array of the receiving antenna are operated in different switching states. For example, a signal with an ascending frequency is received by the antenna array in a first switching state, and a signal with a descending frequency modulation is received by the antenna array in a second switching state. In this case, for the transmission of the transmitted signal in the two modulations, the antenna array of the transmitting antenna is operated in the same switching state. Selectively, various switching states for the transmitting antenna are also possible for various modulations of the transmitted signal.

Japanese Patent Publication No. 2007-187632

In Patent Document 1, signals are transmitted for each antenna array. However, the technology in Patent Document 1 has room for improvement in terms of the effective utilization of multiple antennas.

The objective of this disclosure is to provide a radar system that can effectively utilize multiple antennas.

The following describes the technical means of solving the problem described in this disclosure. Note that the claims and the reference numerals in parentheses in this section indicate the correspondence with the specific means described in the embodiments detailed later, and do not limit the technical scope of this disclosure.

A first aspect of this disclosure is a transmitting antenna system (2) including an antenna that transmits a transmission signal,
A receiving antenna system (3) includes an antenna that receives the transmitted signal reflected from the outside as a received signal,
A control unit (5) that outputs a transmission signal to the transmitting antenna system and acquires a reception signal from the receiving antenna system,
Equipped with,
At least one of the transmitting antenna system and the receiving antenna system includes a set of antennas with different peak gain frequencies.
The control unit is
The system switches between a high-frequency mode that generates a transmission signal with a center frequency corresponding to the antenna with the highest peak frequency among the antenna set, a low-frequency mode that generates a transmission signal with a center frequency corresponding to the antenna with the lowest peak frequency, and a medium-frequency mode that generates a transmission signal with a center frequency within the frequency range from the center frequency in the high-frequency mode to the center frequency in the low-frequency mode .
The receiving antenna system is,
It includes four sets of antennas.
Each antenna set consists of an antenna with a relatively high peak frequency and an antenna with a relatively low peak frequency.
In this radar system, antennas with relatively high peak frequencies are spaced equally apart in multiple sets, and antennas with relatively low peak frequencies are also spaced equally apart. The spacing between antennas with relatively high peak frequencies and the spacing between antennas with relatively low peak frequencies are different in magnitude, and the antennas with relatively high peak frequencies and the antennas with relatively low peak frequencies are arranged symmetrically in the direction of antenna arrangement, with the center of the array of four antennas with relatively high peak frequencies coinciding with the center of the array of four antennas with relatively low peak frequencies .

According to this configuration, in addition to the high-frequency and low-frequency modes corresponding to each antenna, transmission and reception in a medium-frequency mode becomes possible. This allows for signal transmission and reception using a combined antenna, in addition to the signal transmission and reception corresponding to each individual antenna in the set. Therefore, multiple antennas can be effectively utilized.

This is a diagram showing the overall configuration of the first embodiment. This is a schematic diagram showing an example of an antenna configuration. This is a schematic diagram showing an example of an antenna configuration. This is a schematic diagram illustrating the functional configuration of an MMIC (Multi-Microcomputer Interchange). This graph illustrates the characteristics of antenna and filter circuits. This is a schematic diagram illustrating the antenna position. This is a schematic diagram illustrating antenna placement patterns. This is a schematic diagram to explain the phase difference caused by changes in the angle of arrival. This is a flowchart to explain the control flow. This is a schematic diagram showing an example of the configuration of the antenna set in the second embodiment. This is a schematic diagram illustrating the antenna position. This graph illustrates the directional characteristics of the antenna.

The following describes several embodiments of this disclosure with reference to the drawings. Note that in each embodiment, corresponding components are denoted by the same reference numerals, and redundant explanations may be omitted. Furthermore, if only a portion of the configuration is described in each embodiment, the configuration of other embodiments described earlier can be applied to the remaining parts of that configuration. Moreover, not only are the configurations explicitly stated in the description of each embodiment possible, but configurations from multiple embodiments can also be partially combined, even if not explicitly stated, as long as there are no particular problems with the combination.

(First Embodiment)
A first embodiment of the present disclosure will be described with reference to Figures 1 to 9. The radar system 1 is mounted on a moving object such as a vehicle. The radar system 1 transmits a transmission signal, receives the transmission signal reflected by an object as a reception signal, and detects the distance to the target (which is the object that reflected the transmission signal), the relative velocity to the target, and the orientation of the target as target information.

The target information output from radar system 1 is input to the in-vehicle ECU (Electronic control unit) via an in-vehicle network such as CAN (Control Area Network®) and Ethernet®. The in-vehicle ECU then performs various processes for autonomous driving and advanced driver assistance based on the acquired target information for each target.

Examples of processing based on target information include collision avoidance processing and warning processing. Collision avoidance processing involves controlling the braking system, steering system, etc., based on the target information of each target, to control the vehicle in order to avoid a collision with the target. Warning processing is a process that warns the driver of the possibility of a collision with a target based on the target information of each target.

The radar system 1 of this embodiment comprises a transmitting antenna system 2, a receiving antenna system 3, an MMIC 5, and a controller 6. The transmitting antenna system 2 includes at least one transmitting antenna 4, which acts as an antenna for transmitting transmission signals. The transmitting antenna 4 converts the electrical signal supplied from the MMIC 5 into a radio wave signal and transmits it to the outside world. The transmitting antenna 4 is composed of at least one antenna element. For example, as shown in Figure 2, the transmitting antenna 4 is a patch antenna comprising a plurality of flat-plate-shaped antenna elements 40. The antenna elements are arranged on the side of a dielectric substrate opposite to the ground plate, with the ground plate provided on one side, so as to face the ground plate. The plurality of antenna elements 40 are arranged in a predetermined alignment direction. The plurality of antenna elements 40 are connected, for example, in series by a feed line 41 that supplies electrical signals.

The transmitting antenna 4 described above is designed with a wider frequency bandwidth than the receiving antennas 4a and 4b in the receiving antenna system 3 described later, in terms of the shape, size, number, and arrangement of its antenna elements. For example, this antenna is designed to have a frequency bandwidth of 76 GHz to 81 GHz. One transmitting antenna 4 is connected to each transmitting channel in the MMIC 5. Since the total number of transmitting channels in the MMIC in this embodiment is 1, the total number of antennas transmitting the transmission signal is also 1.

As shown in Figure 3, the receiving antenna system 3 includes receiving antennas 4a and 4b, and a filter circuit 42, which receive radio wave signals, including the transmitted signal reflected from the outside, as received signals. The receiving antennas 4a and 4b convert the received signal, as a radio wave signal, into an electrical signal and output it to the MMIC 5. Similar to the transmitting antenna 4, the receiving antennas 4a and 4b are patch antennas, with at least one or more antenna elements 40 connected in series by a feed line 41.

In the receiving antenna system 3, the receiving antennas 4a and 4b are arranged so that two are connected to each receiving channel in the MMIC. Since the total number of receiving channels in the MMIC in this embodiment is four, the total number of receiving antennas is eight. Hereinafter, the sets of receiving antennas 4a and 4b connected to each receiving channel will be referred to as antenna sets RX1, RX2, RX3, and RX4.

In each antenna set RX1, RX2, RX3, and RX4, the receiving antennas 4a and 4b are arranged adjacent to each other. The receiving antennas 4a and 4b are arranged so that the direction of the antenna elements is parallel. Furthermore, each receiving antenna 4a and 4b in a single antenna set RX1, RX2, RX3, and RX4 is designed to have different antenna gain frequency characteristics. Specifically, each antenna set RX1, RX2, RX3, and RX4 has a receiving antenna 4a with a relatively high peak frequency of antenna gain and a receiving antenna 4b with a relatively low peak frequency of antenna gain.

As an example, the high-frequency receiving antenna 4a has a peak frequency of 80.5 GHz, and the low-frequency antenna 4b has a peak frequency of 76.5 GHz. Each receiving antenna 4a and 4b is designed to operate within the frequency band of the transmitting antenna 4 in the transmitting antenna system 2. In other words, each receiving antenna 4a and 4b is designed to have a narrower bandwidth than the transmitting antenna 4. Alternatively, it can be said that the paired antennas 4a and 4b are designed to have a narrower bandwidth than the non-paired antenna 4. That is, in the radar device 1 of this embodiment, the receiving antenna system 3, part of the transmitting antenna system 2 and the receiving antenna system 3, includes a pair of antennas with different frequency characteristics.

The filter circuit 42 is an electrical circuit that suppresses the passage of signals in a specific frequency band. A filter circuit 42 is provided for each receiving antenna 4a and 4b in the receiving antenna system 3. The filter circuit 42 is designed so that, at each receiving antenna 4a and 4b, it has a pass-through characteristic that suppresses signals in the frequency band including the peak frequency of the other receiving antenna 4a or 4b. For example, in the example shown in Figure 5, the filter circuit connected to receiving antenna 4a has a pass-through characteristic that suppresses the frequency band centered around 76.5 GHz. The filter circuit connected to receiving antenna 4b has a pass-through characteristic that suppresses the frequency band centered around 80.5 GHz.

For the receiving antennas 4a and 4b described above, the antenna positions shown in Figure 6 are defined. The antenna position is defined as the shape center of the receiving antennas 4a and 4b as a group of antenna elements 40. Furthermore, for signals with matching antenna gains as shown in Figure 6, the receiving antennas 4a and 4b function as a combined antenna 4c consisting of two rows of antenna elements 40. In this case, the antenna position is defined as the shape center of the combined antenna 4c as a group of antenna elements 40 from each receiving antenna 4a and 4b. In this embodiment, as shown in Figure 6, the central position of the antenna positions of each receiving antenna 4a and 4b becomes the antenna position of the combined antenna 4c.

The receiving antennas 4a and 4b described above are arranged in a predetermined direction with a specified interval between them. The arrangement pattern of receiving antennas 4a and 4b in the entire receiving antenna system 3 will now be explained. As shown in Figure 7, antenna sets RX1, RX2, RX3, and RX4 are arranged sequentially from left to right on the page. Here, the minimum distance between receiving antennas 4a and 4b is denoted as d.

In antenna set RX1, the receiving antenna 4b is positioned on the outside, and the distance between it and the inner, high-frequency antenna 4a is 3d. Adjacent to the receiving antenna 4a in antenna set RX1, the receiving antenna 4b in antenna set RX2 is positioned with a distance d. The receiving antenna 4a in antenna set RX2 is positioned with a distance d relative to the receiving antenna 4b. The receiving antenna 4a in antenna set RX3 is positioned with a distance 2d relative to the receiving antenna 4b in antenna set RX2. Furthermore, the arrangement of the receiving antennas 4a and 4b in antenna sets RX3 and RX4 is a left-right inversion of that in antenna sets RX1 and RX2. As described above, in the receiving antenna system 3, the distances between antennas with high peak frequencies and the distances between antennas with low peak frequencies in the multiple receiving antennas 4a and 4b pairs are different.

The MMIC5 is constructed by integrating various components onto a single semiconductor chip made of materials such as silicon. As shown in Figure 4, the MMIC5 comprises a control unit 50, a transmission signal generation unit 51, and a receiver 52.

The control unit 50 is a digital circuit that, based on control signals from the controller 6, causes the transmission signal generation unit 51 to generate a transmission signal. For example, the control unit 50 generates a transmission signal based on a digital signal that has a predetermined center frequency and whose frequency changes over time.

The transmission signal generation unit 51 receives an instruction signal from the control unit 50 and generates a millimeter-wave transmission signal corresponding to the instruction signal. The transmission signal generation unit 51 is composed of, for example, a D/A converter and a voltage-controlled oscillator. For example, when the transmission signal generation unit 51 receives a digital signal whose frequency changes with time, output as an instruction signal, it converts it to an analog signal using the D/A converter. Then, the transmission signal generation unit 51 generates a high-frequency millimeter-wave signal from this analog signal using the voltage-controlled oscillator and outputs it as a transmission signal to the transmission antenna system 2. Furthermore, the transmission signal generation unit 51 distributes a portion of the output transmission signal from the original signal at a predetermined ratio and outputs it to the receiver 52. In the following, the signal output to the receiver 52 will be referred to as the local signal.

The receiver 52 includes a signal mixing unit 54 and an A/D converter 55. A receiver 52 is provided for each receiving channel. The signal mixing unit 54 generates a beat signal by mixing the local signal from the transmission signal generation unit 51 and the received signal Sr from the receiving antenna, and outputs it to the A/D converter 55. The generated beat signal is an interference signal representing the frequency difference between the received signal and the local signal. The beat signal is output to the A/D converter 55 after high-frequency components that deviate from the frequency difference between the received signal and the local signal are filtered out by a low-pass filter (not shown).

The A/D converter 55 samples the beat signal at predetermined time intervals and converts it into digitized beat signal data. This beat signal data is output to the controller 6 as reception result data related to the received signal.

The MMIC 5 controls the switching of the center frequency of the transmission signal output by the control unit 50. Specifically, the MMIC 5 can execute a high-frequency mode, generating a transmission signal with a center frequency corresponding to the high-frequency receiving antenna 4a of the receiving antenna pair 4a and 4b. Furthermore, the MMIC 5 can execute a low-frequency mode, generating a transmission signal with a center frequency corresponding to the low-frequency receiving antenna 4b. In addition, the MMIC 5 can execute a medium-frequency mode, generating a transmission signal with an intermediate center frequency that falls within the range between the center frequencies of the high-frequency mode and the low-frequency mode. The MMIC 5 switches between these three modes.

Here, the intermediate center frequency in the medium frequency mode is defined as the frequency at which the antenna gains of each receiving antenna 4a and 4b are substantially equal. For example, in this embodiment, as shown in Figure 5, the intermediate center frequency is 78.5 GHz.

In high-frequency modes, the received signal, primarily received by the receiving antenna 4a, is output to the MMIC 5 in the receiving antenna system 3. In the receiving antenna 4b, due to the frequency characteristics of the antenna gain and the pass-through characteristics of the filter circuit 42, the received signal output to the MMIC 5 in high-frequency modes is effectively cut off.

Therefore, in the high-frequency mode, it can be considered virtually equivalent to having only the receiving antenna 4a. That is, in this mode, as shown in Figure 7, the received signal can be considered to be received by four receiving antennas 4a arranged at intervals 2d from each other.

On the other hand, in low-frequency mode, the received signal, primarily received by receiving antenna 4b, is output to MMIC 5, while the received signal received by receiving antenna 4a is effectively cut off. That is, in this mode, as shown in Figure 7, the received signal can be considered to be received by four receiving antennas 4a arranged at intervals 4d from each other.

Furthermore, in the medium frequency mode, the received signal is received by both receiving antennas 4a and 4b of each antenna set and output to the MMIC 5. As a result, the receiving antennas 4a and 4b function as a single combined antenna 4c. In particular, in this embodiment, since the intermediate center frequency is set to a frequency where the antenna gain and filter pass characteristics are substantially the same, the received signal obtained has passed through antennas and filter circuits with substantially identical gain and pass characteristics.

As described above, the entire set of receiving antennas 4a and 4b can be considered as a single combined antenna 4c. Therefore, in this mode, as shown in Figure 7, the received signal can be considered to be received by four receiving antennas 4c arranged at intervals of 3d from each other.

As described above, by switching the center frequency of the transmitted signal, it becomes possible to substantially change and control the arrangement pattern of the receiving antennas. In other words, by controlling the frequency switching, it becomes possible to virtually change and control the spacing between antennas.

By controlling the spacing of the receiving antennas as described above, the field of view and angle measurement accuracy of the radar device 1 can be switched. That is, as shown in Figure 8, the arrival angle θ at each receiving antenna can be estimated by obtaining the phase difference dsinθ of the received signals from each antenna arranged at intervals d. However, if the phase difference dsinθ exceeds half a wavelength of the received signal, accurate angle estimation becomes impossible due to angle folding. In other words, the range of spacing d in which angle folding does not occur is less than half a wavelength.

On the other hand, the larger the interval d, the better the sensitivity to phase difference detection, allowing for the detection of small phase differences, thus improving the accuracy of arrival angle detection. Conversely, the smaller the interval d, the larger the field of view, and the lower the accuracy of arrival angle estimation. And, the larger the interval d, the smaller the field of view, and the higher the accuracy of arrival angle estimation.

Therefore, the field of view and arrival angle estimation accuracy can be switched by virtually changing the arrangement pattern in accordance with the switching control of the center frequency. In particular, in this embodiment, the spacing becomes larger in the low-frequency mode, enabling detection with a wide field of view. In the high-frequency mode, the spacing becomes smaller, enabling highly accurate arrival angle detection. In the medium-frequency mode, the spacing is intermediate between the low-frequency and high-frequency modes, resulting in intermediate performance in both field of view and accuracy.

Controller 6 is a control device that outputs switching commands for each of the modes described above to the MMIC. Controller 6 is configured to include at least one dedicated computer. The dedicated computer constituting Controller 6 may be a sensing ECU (Electronic Control Unit) specialized in controlling the MMIC 5. The dedicated computer constituting Controller 6 may be a sensor integration ECU that comprehensively controls multiple types of sensors mounted on the vehicle. The dedicated computer constituting Controller 6 may be an integrated ECU that integrates the vehicle's driving control. The dedicated computer constituting Controller 6 may be a decision ECU that determines driving tasks in the vehicle's driving control. The dedicated computer constituting Controller 6 may be a monitoring ECU that monitors the vehicle's driving control. The dedicated computer constituting Controller 6 may be an evaluation ECU that evaluates the vehicle's driving control.

The dedicated computer constituting the controller 6 may be a navigation ECU that navigates the vehicle's travel path. The dedicated computer constituting the controller 6 may be a locator ECU that estimates the vehicle's self-state variables. The dedicated computer constituting the controller 6 may be an actuator ECU that controls the vehicle's drive actuators. The dedicated computer constituting the control unit may be an HCU (Human Machine Interface Control Unit) that controls information display in the vehicle. The dedicated computer constituting the controller 6 may be a computer other than the vehicle, for example, one that constructs an external center or mobile terminal capable of communicating with the vehicle.

The dedicated computer constituting the controller 6 has at least one memory 6a and one processor 6b. Memory 3a is at least one type of non-transitory tangible storage medium, such as semiconductor memory, magnetic media, and optical media, which non-temporarily stores programs and data readable by the computer. Here, storage may be accumulation where data is retained even when the sensor system is turned off, or temporary storage where data is erased when the sensor system is turned off. The processor 6b includes at least one type as a core, such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), RISC (Reduced Instruction Set Computer)-CPU, DFP (Data Flow Processor), and GSP (Graph Streaming Processor).

In the controller 6, the processor 6b executes multiple instructions contained in the control program stored in memory 3a to control the transmit/receive unit 20. This allows the controller 6 to construct a functional block for controlling the transmit/receive unit 20.

The radar control method, in which the controller 6 controls the radar device 1 using these functional blocks, is executed according to the control flow shown in Figure 9. This control flow is repeatedly executed during vehicle startup. In this control flow, each "S" represents multiple steps executed by multiple instructions included in the control program.

First, in S10, the controller 6 performs radar operation in the currently set mode, that is, generates a transmit signal at the center frequency corresponding to the mode and processes the reception of the receive signal. In the subsequent S20, it determines whether or not it is time to switch modes. Specifically, it determines whether or not the radar operation in the current mode has been performed for a specified time or a specified number of frames. In this case, the three modes will switch over in a specified order over time.

Alternatively, the controller 6 may determine the switching timing according to the driving scene based on the vehicle's driving area type. For example, the controller 6 may determine that it is time to switch to high-frequency mode when the vehicle enters a highway from a regular road. Furthermore, the controller 6 may determine that it is time to switch to medium-frequency mode when the vehicle is driving on a regular road. In addition, the controller 6 may determine that it is time to switch to low-frequency mode when the vehicle enters an intersection or parking lot.

Alternatively, the controller 6 may determine the switching timing according to the driving scene based on the operation of specific functions in the vehicle. For example, the controller 6 may determine that it is time to switch to high-frequency mode when ACC (Adaptive Cruise Control) starts operating. Furthermore, the controller 6 may determine that it is time to switch to low-frequency mode when AEB (Autonomous Emergency Braking) starts operating. In addition, the controller 6 may determine that it is time to switch to medium-frequency mode when all functions have finished operating. The controller 6 may also appropriately switch between time-based mode switching control and driving scene-based mode switching control.

If it is determined that it is not a switching timing, this flow returns to S10. On the other hand, if it is determined that it is a switching timing, this flow proceeds to S30. In S30, the mode switching is performed.

According to the first embodiment described above, in addition to the high-frequency and low-frequency modes corresponding to each antenna, transmission and reception in a medium-frequency mode becomes possible. This allows for signal transmission and reception using a combined antenna, in addition to the signal transmission and reception corresponding to each individual antenna in the set. Therefore, multiple antennas can be effectively utilized. In particular, in this embodiment, since there is no need to use additional channels and antennas to support multiple modes, costs can be reduced.

(Second Embodiment)
As shown in Figures 10 and 11, the second embodiment is a modification of the first embodiment.

In the second embodiment, the high-frequency receiving antenna 4a and the low-frequency receiving antenna 4b in the antenna set have different shapes. Specifically, one of the antennas (for example, the low-frequency side) has a shape in which multiple rows of antenna elements (three rows in Figure 10) are arranged. Furthermore, all antennas constituting the set are arranged at equal intervals. As a result, in the mode transmitting the intermediate center frequency, the center position of the antenna with four rows of antenna elements becomes the equivalent antenna position.

In this case, in medium-frequency mode, the center position of the receiving antenna 4c is located at a position offset from the midpoint between the antenna position in high-frequency mode and the antenna position in low-frequency mode. As shown in Figure 11, when multiple receiving antennas 4b are arranged in rows, the antenna position in medium-frequency mode is closer to the antenna position in low-frequency mode.

As described above, the antenna position in the medium frequency mode is determined at least by the antenna configuration. In this embodiment, the directivity of the receiving antennas 4a and 4b can also be changed, as described in the third embodiment below.

(Third Embodiment)
As shown in Figure 12, the third embodiment is a modification of the first embodiment.

In the third embodiment, the receiving antennas 4a and 4b in the antenna set have different directional characteristics in terms of antenna gain. Specifically, as shown in Figure 10, one antenna (for example, the low-frequency side) has a shape in which multiple rows (for example, three rows) of antenna elements 40 are arranged. The rows of antenna elements 40 constituting the antenna set are arranged at equal intervals.

In this case, as shown in Figure 12, the receiving antenna 4a has a directivity that obtains antenna gain over a wider azimuth range compared to the receiving antenna 4b. Furthermore, the receiving antenna 4b has a directivity that obtains antenna gain over a greater distance than the receiving antenna 4a. The frequency characteristics of the antenna gain and the pass-through characteristics of the filter circuit for the receiving antennas 4a and 4b are assumed to be the same as in the first embodiment.

As a result, in the medium frequency mode, the received signal is equivalent to being received by a single receiving antenna 4c, which has a combined directivity of receiving antenna 4a and receiving antenna 4b. As shown in Figure 12, the combined directivity in the medium frequency mode has a narrower angle and provides antenna gain over a longer distance than the high-frequency antennas.

In other words, by having the MMIC 5 perform frequency switching control, target detection processing becomes possible with different directivity for each mode. In this embodiment, the low-frequency mode enables wider-angle target detection at relatively close range. The high-frequency mode enables target detection at a narrower angle and further distance than the low-frequency mode. Furthermore, the medium-frequency mode enables target detection at an even narrower angle and further distance than the high-frequency mode. In short, the field of view and detection distance of the radar device 1 are changed by frequency switching control.

Furthermore, instead of the receiving antennas 4a and 4b, the transmitting antenna 4 may be configured with the antenna set shown in Figure 10. In this case as well, since the transmission signal is transmitted using a radiation pattern corresponding to each directional characteristic, the field of view and detection distance for target detection in the radar device 1 are changed by frequency switching control, similar to the case of the receiving antenna.

(Other embodiments)
Although several embodiments have been described above, this disclosure is not intended to be limited to those embodiments, and can be applied to various embodiments and combinations without departing from the spirit of this disclosure.

In the modified example, the transmitting antenna system 2 may include a set of transmitting antennas 4 with different frequency characteristics. Furthermore, the MMIC 5 may have multiple transmitting channels, and each transmitting channel may be connected to either a single transmitting antenna 4 or a set of transmitting antennas 4.

In the modified example, the dedicated computer constituting the controller 6 may have at least one of the digital and analog circuits as a processor. Here, the digital circuit refers to at least one of the following: ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), SOC (System on a Chip), PGA (Programmable Gate Array), and CPLD (Complex Programmable Logic Device). Furthermore, such a digital circuit may have memory for storing programs.

In the modified configuration, the mobile body to which the radar system 1 is applied may be, for example, an autonomous mobile robot capable of cargo transport or information collection by autonomous or remote driving. In addition to the embodiments described so far, the above-described embodiments and modifications may be implemented in the form of a processing circuit (e.g., a processing ECU) or a semiconductor device (e.g., a semiconductor chip) as a control device configured to be mounted on a host mobile body and having at least one processor 3b and one memory 3a.

(Note)
This specification discloses several technical concepts and several combinations thereof, as listed below.

(Technical thought 1)
A transmitting antenna system (2) including an antenna that transmits a transmission signal,
A receiving antenna system (3) including the antenna that receives the transmitted signal reflected from the outside as a received signal,
A control unit (5) that outputs the transmission signal to the transmitting antenna system and acquires the reception signal from the receiving antenna system,
Equipped with,
At least one of the transmitting antenna system and the receiving antenna system includes a set of antennas with different peak gain frequencies.
The control unit is
A radar device that switches between a high-frequency mode that generates a transmission signal with a center frequency corresponding to the antenna with the higher peak frequency among the set of antennas, a low-frequency mode that generates a transmission signal with a center frequency corresponding to the antenna with the lower peak frequency, and a medium-frequency mode that generates a transmission signal with a center frequency that falls within the frequency range from the center frequency in the high-frequency mode to the center frequency in the low-frequency mode.

(Technical thought 2)
The radar apparatus according to technical concept 1, wherein the control unit generates the transmission signal in the medium frequency mode, with the center frequency being the frequency at which the gains of each of the antennas within the frequency range coincide.

(Technical thought 3)
The aforementioned receiving antenna system is
It includes multiple sets of the aforementioned antennas,
A radar device according to technical concept 1 or technical concept 2, wherein the spacing between antennas with high peak frequencies and the spacing between antennas with low peak frequencies in a plurality of sets of antennas are arranged to be different.

(Technical thought 4)
The radar device according to any one of Technical Concepts 1 to 3, wherein each of the antennas in the set comprises the antennas having different gain directional characteristics.

(Technical Thought 5)
The control unit is a radar device according to any one of Technical Concepts 1 to 4 that temporally switches between the high-frequency mode, the low-frequency mode, and the medium-frequency mode.

(Technical Thought 6)
The control unit is a radar device according to any one of Technical Concepts 1 to 5, which temporally switches between the high-frequency mode, the low-frequency mode, and the medium-frequency mode depending on the driving scene of the vehicle on which it is installed.

1: Radar system, 2: Transmitting antenna system, 3: Receiving antenna system, 5: MMIC (Control Unit)

Claims (5)

A transmitting antenna system (2) including an antenna that transmits a transmission signal,
A receiving antenna system (3) including the antenna that receives the transmitted signal reflected from the outside as a received signal,
A control unit (5) that outputs the transmission signal to the transmitting antenna system and acquires the reception signal from the receiving antenna system,
Equipped with,
At least one of the transmitting antenna system and the receiving antenna system includes a set of antennas with different peak gain frequencies.
The control unit is
The system switches between a high-frequency mode that generates a transmission signal with a center frequency corresponding to the antenna with the higher peak frequency among the antenna set, a low-frequency mode that generates a transmission signal with a center frequency corresponding to the antenna with the lower peak frequency, and a medium-frequency mode that generates a transmission signal with a center frequency that falls within the frequency range from the center frequency in the high-frequency mode to the center frequency in the low-frequency mode .
The aforementioned receiving antenna system is
It includes four sets of the aforementioned antennas,
Each of the aforementioned antenna sets is a set consisting of an antenna with a relatively high peak frequency and an antenna with a relatively low peak frequency.
A radar device in which the antennas with relatively high peak frequencies in a plurality of sets are spaced at equal intervals, and the antennas with relatively low peak frequencies are also spaced at equal intervals, the spacing between the antennas with relatively high peak frequencies and the spacing between the antennas with relatively low peak frequencies are different in magnitude, and the antennas with relatively high peak frequencies and the antennas with relatively low peak frequencies are arranged so that their arrangement is symmetrical in the direction of the antenna arrangement, and the center of the arrangement of the four antennas with relatively high peak frequencies coincides with the center of the arrangement of the four antennas with relatively low peak frequencies . The radar apparatus according to claim 1, wherein the control unit generates the transmission signal in the medium frequency mode, with the center frequency being the frequency at which the gains of each of the antennas within the frequency range coincide. The radar apparatus according to claim 1, wherein each of the antennas in the set comprises antennas with different gain directional characteristics. The radar apparatus according to claim 1, wherein the control unit switches between the high-frequency mode, the low-frequency mode, and the medium-frequency mode over time. The radar device according to claim 1, wherein the control unit temporally switches between the high-frequency mode, the low-frequency mode, and the medium-frequency mode according to the driving scene of the vehicle on which it is installed.