radar equipment

Abstract

To provide a radar device capable of performing phase compensation between receiving circuits, and capable of suppressing degradation in angular resolution.SOLUTION: A control unit of a radar device executes switching between an overlapping mode in which a center frequency of a transmission signal is changed to allow virtual duplication with regard to a position of a receiving antenna connected to a different receiving circuit, and a non-overlapping mode. In the overlapping mode, virtual duplication of a position of a receiving antenna connected to a different receiving circuit is allowed. In the non-overlapping mode, virtual duplication of an antenna position is prohibited. In the overlapping mode, the control unit executes implementation of phase compensation of both receiving circuits according to a phase difference of both reception signals received by a receiving antenna with a duplicated position.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] This disclosure relates to a radar device.

Background Art

[0002] Patent Document 1 discloses a radar device that compensates for the phase difference between different reception circuits. This radar device includes a plurality of reception antennas, a first transmission antenna and a second transmission antenna, and a phase compensation unit. The plurality of reception antennas are provided in a plurality of reception circuits. The first transmission antenna and the second transmission antenna are provided at a predetermined interval from the reception antennas so that the positions of the reception antennas virtually overlap. The phase compensation unit compensates for the phase difference between the reception circuits of the reflected waves of the respective transmission waves transmitted from the first and second transmission antennas based on the comparison result of the respective reception signals received by the respective reception antennas provided to virtually overlap.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, there are reception antennas whose positions virtually overlap. However, in a MIMO (Multiple-Input and Multiple-Output) radar device that virtually increases the reception antennas according to the phase difference between a plurality of transmission antennas, if there are reception antennas whose positions virtually overlap, the number of virtual reception antennas will decrease. When the number of virtual reception antennas decreases, the angular resolution may decrease.

[0005] The objective of this disclosure is to provide a radar device that enables phase compensation between receiving circuits and suppresses a decrease in angular resolution. [Means for solving the problem]

[0006] 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.

[0007] A first aspect of this disclosure is a transmitting antenna system (2) comprising a plurality of transmitting antenna units (TX1, TX2) including a pair of transmitting antennas (20a, 20b) with different peak gain frequencies, A receiving antenna system (3) comprising multiple receiving antenna units (RX1, RX2, RX3, RX4) including sets of receiving antennas (30a, 30b) with different peak frequencies, A control unit (6) controls the operation of a transmitting circuit (50) that generates a transmitting signal transmitted from a transmitting antenna system, and a plurality of receiving circuits (53) that process a received signal received by a receiving antenna system. Equipped with, The control unit is By changing the center frequency of the transmitted signal, it is possible to switch between an overlap mode, which allows for a virtual overlap in the positions of receiving antennas connected to different receiving circuits due to the phase difference corresponding to the spacing between transmitting antennas in each transmitting antenna unit, and a non-overlap mode, which prohibits this virtual overlap in positions. In overlap mode, phase compensation is performed between receiving circuits according to the phase difference between received signals received by receiving antennas whose positions overlap. Configured to perform 、 Switching between overlap mode and non-overlap mode, The central frequency is switched between a high central frequency, which corresponds to the transmitting antenna with a high peak frequency, and a low central frequency, which corresponds to the transmitting antenna with a low peak frequency, among the set of transmitting antennas. By switching the center frequency between a high center frequency, a low center frequency, and an intermediate center frequency within the frequency range from the high to the low center frequency, it is possible to switch between multiple overlap modes with different center frequencies and non-overlap modes with the remaining center frequencies. including It is a radar device.

[0008] In this embodiment, phase compensation between receiving circuits is performed in an overlap mode in which virtual overlap of the receiving antenna positions is permitted. Furthermore, since it is possible to switch between this overlap mode and a non-overlap mode, transmission and reception processing may be possible in a non-overlap mode in which the receiving antenna positions do not virtually overlap. Therefore, phase compensation between receiving circuits can be performed, and a decrease in angular resolution can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the overall configuration of the radar device in the first embodiment. [Figure 2] This is a schematic diagram illustrating the functional configuration of the transmitting and receiving unit. [Figure 3] This graph illustrates the characteristics of antenna and filter circuits. [Figure 4] This is a schematic diagram illustrating an example of an antenna configuration and antenna placement. [Figure 5] This is a schematic diagram illustrating an example of antenna placement. [Figure 6] This is a schematic diagram illustrating an example of how the arrangement pattern changes when the antenna position is changed. [Figure 7] This is a flowchart illustrating the radar control method in the first embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, one embodiment of this disclosure will be described with reference to the drawings.

[0011] (First Embodiment) Regarding the first embodiment of the present disclosure, it will be described with reference to FIGS. 1 to 7. The radar device 1 is mounted on a moving body such as a vehicle. The radar device 1 transmits a transmission signal, receives the transmission signal reflected by an object as a reception signal, and detects the distance to a target, which is an object that reflects the transmission signal, the relative speed with the target, the azimuth of the target, etc. as target information.

[0012] The target information output from the radar device 1 is input to an in-vehicle ECU (Electronic Control Unit) via an in-vehicle network such as CAN (Control Area Network (registered trademark)) and Ethernet (registered trademark). The in-vehicle ECU executes various processes for automatic driving and advanced driving assistance of the vehicle based on the target information of each acquired target.

[0013] Examples of the processes based on the target information include a collision avoidance process, a warning process, etc. The collision avoidance process is a process for performing vehicle control to avoid a collision with a target by controlling a braking system, a steering system, etc. based on the target information of each target. The warning process is a process for warning a driver of the possibility of a collision with a target based on the target information of each target.

[0014] The radar device 1 of the present embodiment includes a transmission antenna system 2, a reception antenna system 3, a transmission / reception unit 5, and a controller 6. The transmission antenna system 2 includes a plurality of transmission antennas 20a and 20b as antennas for transmitting a transmission signal.

[0015] Specifically, the transmission antenna system 2 includes a plurality of transmission antenna units TX1 and TX2 each having a pair of transmission antennas 20a and 20b. Each of the transmission antenna units TX1 and TX2 includes a pair of transmission antennas 20a and 20b and a filter circuit 22.

[0016] The transmitting antennas 20a and 20b convert the electrical signals supplied from the transmitting / receiving unit 5 as transmission signals into radio signals and transmit them to the outside world. The transmitting antennas 20a and 20b are composed of at least one antenna element. For example, the transmitting antennas 20a and 20b are patch antennas equipped with multiple flat-plate shaped antenna elements 40 as shown in Figure 4. The antenna elements are arranged on the side opposite to the ground plate of a dielectric substrate, where the ground plate is provided on one side, so as to face the ground plate. The multiple antenna elements 40 are arranged in a predetermined alignment direction. The multiple antenna elements 40 are connected, for example, in series by a feed line 41 that supplies electrical signals.

[0017] The pairs of transmitting antennas 20a and 20b in each transmitting antenna unit TX1 and TX2 are arranged adjacent to each other. The pairs of transmitting antennas 20a and 20b are arranged so that the direction of the antenna elements is parallel. Furthermore, each transmitting antenna 20a and 20b in a single transmitting antenna unit TX1 and TX2 is designed to have different peak antenna gain frequencies. Specifically, each transmitting antenna unit TX1 and TX2 has a high-frequency transmitting antenna 20a with a relatively high peak antenna gain and a low-frequency transmitting antenna 20b with a relatively low peak antenna gain. For example, transmitting antenna 20a has a peak frequency of 80.5 GHz, and transmitting antenna 20b has a peak frequency of 76.5 GHz.

[0018] In one transmitting antenna unit TX1, TX2, the above pair of transmitting antennas 20a, 20b is connected to one transmitting channel CHt1, CHt2 in the transmitting / receiving unit 5. In this embodiment, since two transmitting antenna units TX1, TX2 are provided, two pairs of transmitting antennas 20a, 20b are connected to each of the transmitting channels CHt1, CHt2 in the transmitting / receiving unit 5.

[0019] The filter circuit 22 is an electrical circuit that suppresses the passage of signals in a specific frequency band. A filter circuit 22 is provided for each transmitting antenna 20a, 20b. The filter circuit 22 is designed to have a pass-through characteristic that suppresses signals in the frequency band including the peak frequency of the other transmitting antenna 20a, 20b. For example, in the example shown in Figure 3, the filter circuit connected to transmitting antenna 20a has a pass-through characteristic that suppresses the frequency band centered around 76.5 GHz. The filter circuit connected to transmitting antenna 20b has a pass-through characteristic that suppresses the frequency band centered around 80.5 GHz.

[0020] For the transmitting antennas 20a and 20b described above, the antenna positions shown in Figure 4 are defined. The antenna position is defined as the center of the shape of the transmitting antennas 20a and 20b as groups of antenna elements 40. Furthermore, for signals at frequencies where the antenna gains shown in Figure 3 match, the receiving antennas 30a and 30b function as a combined antenna 20c consisting of two rows of antenna elements 40. In this case, the antenna position is defined as the center of the shape of the combined antenna 20c as a group of antenna elements 40 from each transmitting antenna 20a and 20b. In this embodiment, as shown in Figure 4, the center of the antenna positions of each transmitting antenna 20a and 20b becomes the antenna position of the combined antenna 20c.

[0021] The receiving antenna system 3 includes multiple receiving antenna units RX1, RX2, RX3, and RX4. Each receiving antenna unit RX1, RX2, RX3, and RX4 is equipped with a set of receiving antennas 30a and 30b, which are antennas that receive radio signals, including the transmitted signal reflected from the outside, as a received signal. Each receiving antenna unit RX1, RX2, RX3, and RX4 is further equipped with a filter circuit 32.

[0022] The receiving antennas 30a and 30b convert the received signal, which is a radio wave signal, into an electrical signal and output it to the transmitting / receiving unit 5. The receiving antennas 30a and 30b are patch antennas, similar to the transmitting antennas 20a and 20b, in which at least one antenna element 40 is connected in series by a feed line 41.

[0023] The receiving antennas 30a and 30b in each receiving antenna unit RX1, RX2, RX3, and RX4 are arranged adjacent to each other. The receiving antennas 30a and 30b are arranged so that the direction of the antenna elements is parallel. Furthermore, the receiving antennas 30a and 30b in a single receiving antenna unit RX1, RX2, RX3, and RX4 are designed to have different peak frequencies of antenna gain. The receiving antennas 30a and 30b are designed so that their frequency characteristics of antenna gain are substantially the same as those of the transmitting antennas 20a and 20b, respectively. That is, each receiving antenna unit RX1, RX2, RX3, and RX4 has a high-frequency receiving antenna 30a with a peak frequency of antenna gain substantially equivalent to that of the transmitting antenna 20a (e.g., 80.5 GHz). And each receiving antenna unit RX1, RX2, RX3, and RX4 has a low-frequency receiving antenna 30b with a peak frequency of antenna gain substantially equivalent to that of the transmitting antenna 20b (e.g., 76.5 GHz).

[0024] The filter circuit 32 is designed to have the same pass characteristics as the filter circuit 22 in the transmitting antenna units TX1 and TX2. That is, the filter circuit 32 is designed to have pass characteristics that suppress signals in the frequency band including the peak frequency of the other receiving antenna 30a and 30b at one receiving antenna 30a and 30b. The pass characteristics of the filter circuit 32 in this embodiment are substantially equivalent to those shown in Figure 3, i.e., those of the filter circuit 22 in the transmitting antenna unit.

[0025] For the receiving antennas 30a and 30b described above, the antenna positions shown in Figure 4 are defined, similar to those for the transmitting antennas 20a and 20b. Since the frequency characteristics are substantially the same as those of the transmitting antennas 20a and 20b, the antenna position of the combined antenna 30c, which is the group of antenna elements 40 from each receiving antenna 30a and 30b, is the central position of the antenna positions of each receiving antenna 30a and 30b.

[0026] The transmitting antennas 20a and 20b, and the receiving antennas 30a and 30b are arranged in a predetermined direction with a specified interval between them. An example of the arrangement pattern for each antenna 20a, 20b, 30a, and 30b is described below.

[0027] In this embodiment, as shown in Figure 5, the receiving antenna units RX1, RX2, RX3, and RX4 are arranged in order from left to right on the page in a predetermined orientation. The positional relationship of the receiving antennas 30a and 30b in the X direction is the same for each receiving antenna unit RX1, RX2, RX3, and RX4. For example, the low-frequency receiving antenna 30b is positioned on the left side of the page, and the high-frequency receiving antenna 30a is positioned on the right side. All receiving antennas 30a and 30b in the receiving antenna system 3 are arranged at equal intervals with a gap d between them. The receiving antennas 30a and 30b are arranged alternately, with high-frequency and low-frequency antennas alternating.

[0028] The transmitting antenna units TX1 and TX2 are arranged so that the positional relationship between the transmitting antennas 20a and 20b is symmetrical. Specifically, the transmitting antennas 20a and 20b of transmitting antenna unit TX1 are positioned so that the low-frequency side is on the left side of the page and the high-frequency side is on the right side of the page. Similarly, the transmitting antennas 20a and 20b of transmitting antenna unit TX2 are positioned so that the low-frequency side is on the right side of the page and the high-frequency side is on the left side of the page.

[0029] The transmitting antennas 20a and 20b of each transmitting antenna unit TX1 and TX2 are positioned with a spacing of 2d, which is twice the spacing between the receiving antennas 30a and 30b. Furthermore, adjacent transmitting antennas in transmitting antenna unit TX1 and transmitting antenna unit TX2 are positioned with a spacing of 4d, which is four times the spacing between the receiving antennas 30a and 30b. In other words, the transmitting antennas 20a and 20b in transmitting antenna system 2 are positioned at even multiples of the spacing between the receiving antennas 30a and 30b.

[0030] The transmitting / receiving unit 5 is mainly composed of semiconductor integrated circuit devices such as an MMIC (Monolithic Microwave Integrated Circuit). As shown in Figure 2, the transmitting / receiving unit 5 includes a transmitting circuit 50 and a plurality of receiving circuits 53.

[0031] The transmission circuit 50 comprises a transmission control unit 51 and a transmission signal generation unit 52. The transmission control unit 51 is a digital circuit and, based on a control signal from the controller 6, causes the transmission signal generation unit 52 to generate a transmission signal. For example, the transmission control unit 51 generates a transmission signal based on a digital signal that has a predetermined center frequency and whose frequency changes according to time.

[0032] The transmission signal generation unit 52 receives an instruction signal from the transmission control unit 51 and generates a millimeter-wave band transmission signal corresponding to the instruction signal. The transmission signal generation unit 52 is configured to include, for example, a D / A converter and a voltage-controlled oscillator.

[0033] For example, when the transmission signal generation unit 52 receives a digital signal whose frequency changes with time, which is output as an instruction signal, it converts it into an analog signal using a D / A converter. Then, the transmission signal generation unit 52 generates a high-frequency signal in the millimeter-wave band from this analog signal using a voltage-controlled oscillator and outputs it as a transmission signal to the transmission antenna system 2. As a result, the transmission circuit 50 generates a so-called chirp signal whose frequency changes with time. The transmission signal generation unit 52 also distributes a portion of the output transmission signal from the original signal at a predetermined ratio and outputs it to the receiving circuit 53. In the following, the signal output to the receiving circuit 53 will be referred to as the local signal.

[0034] Each of the multiple receiving circuits 53 has a signal mixing unit 54 and an A / D converter 55, and processes the received signal received by the receiving antenna. Each receiving circuit 53 is mounted on, for example, a different semiconductor chip. Each receiving circuit 53 processes the received signal input from a different receiving channel. As an example, the transmitting / receiving unit 5 is provided with two receiving circuits 53: one connected to receiving channels CHr1 and CHr2, and another connected to receiving channels CHr3 and CHr4.

[0035] Each receiving circuit 53 has the same number of signal mixing units 54 and A / D converters 55 as there are receiving channels CHr1, CHr2, CHr3, CHr4 to which the receiving circuit 53 is connected, and each is connected to the corresponding receiving channel. The signal mixing unit 54 generates a beat signal by mixing the local signal from the transmitting signal generation unit 52 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 that represents 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).

[0036] 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.

[0037] The transmitting / receiving unit 5 can switch the center frequency of the transmission signal output by the transmission control unit 51. Specifically, the transmitting / receiving unit 5 can generate a center frequency (high center frequency) corresponding to the high-frequency receiving antenna 30a of the receiving antennas 30a and 30b pair. The transmitting / receiving unit 5 can also generate a transmission signal with a center frequency (low center frequency) corresponding to the low-frequency receiving antenna 30b. Furthermore, the transmitting / receiving unit 5 can generate a transmission signal with an intermediate center frequency that falls within the frequency range from the high center frequency to the low center frequency. The transmitting / receiving unit 5 can switch the generation of transmission signals with these three center frequencies according to control from the controller 6.

[0038] Here, the intermediate center frequency is defined as the frequency at which the antenna gains of the receiving antennas 30a and 30b (and the transmitting antennas 20a and 20b) are substantially equal. For example, in this embodiment, as shown in Figure 3, the intermediate center frequency is 78.5 GHz.

[0039] When a high-center-frequency transmission signal is generated, the transmission signal is mainly transmitted from the transmitting antenna 20a in the transmitting antenna system 2. In the transmitting antenna 20b, the transmission signal from the transmitting / receiving unit 5 is effectively cut off due to the frequency characteristics of the antenna gain and the pass-through characteristics of the filter circuit 22.

[0040] Furthermore, when a high-center-frequency transmission signal is transmitted, the receiving antenna system 3 outputs the received signal, mainly received by the receiving antenna 30a, to the transmitting / receiving unit 5. Due to the frequency characteristics of the antenna gain and the pass-through characteristics of the filter circuit 32, the received signal output from the receiving antenna 30b to the transmitting / receiving unit 5 is effectively cut off.

[0041] Therefore, when a high-center-frequency transmission signal is generated, it can be considered to be substantially equivalent to having only the high-frequency antennas 20a and 30b in the transmitting antenna system 2 and the receiving antenna system 3. In other words, it can be considered that the transmission signal is transmitted by the two transmitting antennas 20a arranged at a distance of 4d in the transmitting antenna system 2. And in the receiving antenna system 3, it can be considered that the received signal is received by the four receiving antennas 30a arranged at a distance of 2d.

[0042] Therefore, in this case, the received signal from the transmitting antenna unit TX1 to the receiving antenna unit RX3 is essentially in phase with the received signal from the transmitting antenna unit TX2 to the receiving antenna unit RX1. Furthermore, the received signal from the transmitting antenna unit TX1 to the receiving antenna unit RX4 is essentially in phase with the received signal from the transmitting antenna unit TX2 to the receiving antenna unit RX2 (see Figure 6).

[0043] On the other hand, when a low-center-frequency transmission signal is generated, the transmission signal is mainly transmitted from the low-frequency transmitting antenna 20b in the transmitting antenna system 2. At the high-frequency transmitting antenna 20a, the transmission signal from the transmitting / receiving unit 5 is effectively cut off due to the frequency characteristics of the antenna gain and the pass-through characteristics of the filter circuit 22.

[0044] Furthermore, when a low-center-frequency transmission signal is transmitted, the receiving antenna system 3 outputs the received signal, mainly received by the receiving antenna 30b, to the transmitting / receiving unit 5. Due to the frequency characteristics of the antenna gain and the pass-through characteristics of the filter circuit 32, the received signal output from the receiving antenna 30a to the transmitting / receiving unit 5 is effectively cut off.

[0045] In other words, when a low center frequency transmission signal is generated, it can be considered that the transmission signal is transmitted by two transmitting antennas 20b arranged at an interval of 8d in the transmitting antenna system 2. Then, it can be considered that the received signal is received by four receiving antennas 30b arranged at an interval of 2d in the receiving antenna system 3.

[0046] Therefore, in this case, the transmitted signal from the transmitting antenna unit TX1 and the received signal from each receiving antenna unit RX1 will all be in different phases. In other words, in low-frequency mode, this can be considered to be substantially equivalent to acquiring the received signal with eight virtual receiving antennas located at different positions.

[0047] Then, when a transmission signal at the intermediate center frequency is generated, transmission signals of substantially equivalent strength are transmitted from each transmitting antenna 20a and 20b. As a result, the pair of transmitting antennas 20a and 20b functions as a single combined antenna 20c.

[0048] Furthermore, when a transmission signal at the intermediate center frequency is transmitted, the signal is received by both receiving antennas 30a and 30b in each receiving antenna unit, and signals of substantially equivalent strength are output from each receiving antenna 30a and 30b. As a result, the pair of receiving antennas 30a and 30b functions as essentially a single combined antenna 30c.

[0049] Therefore, in this case, the transmitting signal can be considered to be transmitted by two composite antennas 20c arranged at an interval of 6d in the transmitting antenna system 2. And, the receiving signal can be considered to be received by four composite antennas 4c arranged at an interval of 2d in the receiving antenna system 3.

[0050] Therefore, in this case, the transmitted signal from the transmitting antenna unit TX1 and the received signal from the receiving antenna unit RX4 are essentially in phase, and the transmitted signal from the transmitting antenna unit TX2 and the received signal from each receiving antenna unit RX1 are essentially in phase.

[0051] As described above, by switching the center frequency of the transmitted signal, it becomes possible to substantially change and control the arrangement patterns of each antenna 20a, 20b, 30a, and 30b.

[0052] By switching these arrangement patterns, it is possible to switch between an arrangement pattern in which the receiving antennas do not virtually overlap and an arrangement pattern in which they virtually overlap. In particular, in the virtually overlapping arrangement pattern, the receiving antennas 30a and 30b connected to different receiving circuits 53 are in an overlapping arrangement pattern. In this embodiment, the former arrangement pattern is the pattern when the transmission signal is generated at a low center frequency. The latter arrangement pattern is the pattern when the transmission signal is generated at a high center frequency and an intermediate center frequency. In particular, in this embodiment, there are two arrangement patterns in which the receiving antennas 30a and 30b virtually overlap.

[0053] Controller 6 is a control unit that outputs switching commands for each of the modes described above to the transmitting / receiving unit 5. Controller 6 is configured to include at least one dedicated computer. The dedicated computer that makes up Controller 6 may be a sensing ECU (Electronic Control Unit) specialized in controlling the transmitting / receiving unit 5. The dedicated computer that makes up Controller 6 may be a sensor integration ECU that comprehensively controls multiple types of sensors mounted on the vehicle. The dedicated computer that makes up Controller 6 may be an integration ECU that integrates the driving control of the vehicle. The dedicated computer that makes up Controller 6 may be a decision ECU that determines driving tasks in the driving control of the vehicle. The dedicated computer that makes up Controller 6 may be a monitoring ECU that monitors the driving control of the vehicle. The dedicated computer that makes up Controller 6 may be an evaluation ECU that evaluates the driving control of the vehicle.

[0054] The dedicated computer constituting the controller 6 may be a navigation ECU that navigates the vehicle's driving path. The dedicated computer constituting the controller 6 may be a locator ECU that estimates the vehicle's own state variables. The dedicated computer constituting the controller 6 may be an actuator ECU that controls the vehicle's driving actuators. The dedicated computer constituting the control unit may be an HCU (HMI (Human Machine Interface) Control Unit) that controls the presentation of information in the vehicle. The dedicated computer constituting the controller 6 may be a computer other than the vehicle that, for example, constructs an external center or mobile terminal that can communicate with the vehicle.

[0055] The dedicated computer comprising the controller 6 has at least one memory 6a and one processor 6b. The 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 that can be read 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).

[0056] 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.

[0057] The processor 6b of the controller 6 changes the center frequency of the transmitted signal by outputting control commands to the transmit / receive unit 5. This allows the processor 6b to switch between overlap mode and non-overlap mode as the radar's operating modes. Overlap mode allows for a virtual overlap of antenna positions of receiving antennas connected to different receiving circuits, based on the phase difference corresponding to the spacing between transmitting antennas in each transmitting antenna unit. Non-overlap mode prohibits this virtual overlap of antenna positions.

[0058] More specifically, the controller 6 switches between multiple overlap modes with different center frequencies and non-overlap modes with the remaining center frequencies by switching the center frequency between a high center frequency, a low center frequency, and an intermediate center frequency. In this embodiment, as shown in Figure 6, the controller 6 can switch between two overlap modes with high and intermediate center frequencies and one overlap mode with a low center frequency.

[0059] Furthermore, in overlap mode, the controller 6 performs phase compensation between receiving circuits according to the phase difference between the received signals received by receiving antennas whose antenna positions overlap. In particular, the controller 6 in this embodiment performs phase compensation according to the phase difference between the received signals acquired in each overlap mode with different center frequencies.

[0060] Due to the functions of the processor 6b, the radar control method by which the controller 6 controls the radar device 1 is executed according to the control flow shown in Figure 7. This control flow is executed repeatedly during vehicle startup. In this control flow, each "S" represents multiple steps executed by multiple instructions included in the control program.

[0061] First, in S10, the controller 6 sets the radar operation mode to low-frequency mode, that is, a mode in which the receiving antennas do not virtually overlap. In the following S20, the controller 6 instructs the transmit / receive unit 5 to perform radar operation in low-frequency mode. That is, it performs the generation of the transmit signal and the reception processing of the receive signal. In the following S30, the controller 6 determines whether a specified time has elapsed since the start of radar operation in low-frequency mode.

[0062] If it is determined that the specified time has not elapsed, this flow returns to S10. On the other hand, if it is determined that the specified time has elapsed, this flow proceeds to S40.

[0063] In S40, the controller 6 sets the center frequency of the transmitted signal in radar operation to a high center frequency. Then, in S50, the controller 6 instructs the transmit / receive unit 5 to perform radar operation at the high center frequency.

[0064] In S60, the phase difference between the receiving circuits 53 is acquired based on the received signal obtained during radar operation at a high center frequency. Specifically, the controller 6 acquires the phase difference between beat signals based on the received signals obtained from receiving antenna units whose antenna positions virtually overlap.

[0065] More specifically, controller 6 acquires a beat signal based on the received signal from the receiving antenna unit RX3, which is the transmission signal from the transmitting antenna unit TX1. Furthermore, controller 6 acquires a beat signal based on the received signal from the receiving antenna unit RX1, which is the transmission signal from the transmitting antenna unit TX2. Then, controller 6 calculates the phase difference of each beat signal by performing an FFT (Fast Fourier Transform) operation on each beat signal.

[0066] Next, in S70, the controller 6 sets the center frequency of the transmitted signal in radar operation to the intermediate center frequency. Then, in S80, the controller 6 executes radar operation at the intermediate center frequency.

[0067] In the S90, controller 6 acquires a beat signal based on the received signal from the transmitting antenna unit TX1, which is received by the receiving antenna unit RX4. Furthermore, controller 6 acquires a beat signal from the transmitting antenna unit TX2, which is received by the receiving antenna unit RX1. Then, controller 6 calculates the phase difference of each beat signal by performing an FFT process on each beat signal.

[0068] Furthermore, in the next step S100, the controller 6 performs phase compensation using calibration information that integrates this difference information with the difference information acquired at high center frequencies. The controller 6 can obtain the calibration information by, for example, calculating the average or median value of each difference information. For example, the controller 6 can store the calibration information in a storage medium such as memory 6a. The stored calibration information is used to correct the phase of the received signal acquired during radar operation at low center frequencies.

[0069] According to the first embodiment described above, phase compensation between receiving circuits is performed in overlap mode, which allows for a virtual overlap of antenna positions. Since it is possible to switch between this overlap mode and non-overlap mode, transmission and reception processing may be possible in non-overlap mode, where the positions of the receiving antennas do not virtually overlap. Therefore, phase compensation between receiving circuits can be performed, and a decrease in angular resolution can be suppressed.

[0070] Furthermore, according to the first embodiment, switching between overlap mode and non-overlap mode involves switching the center frequency between a high center frequency and a low center frequency. Therefore, it becomes possible to effectively utilize antennas with high peak frequencies and antennas with low peak frequencies.

[0071] Furthermore, according to the first embodiment, the center frequency can be switched between a high center frequency, a low center frequency, and an intermediate center frequency. Switching between overlap mode and non-overlap mode involves switching between multiple overlap modes with different center frequencies and non-overlap modes with the remaining center frequencies. Therefore, in overlap mode, the number of combinations of virtual overlapping antenna positions can increase in proportion to the number of overlap modes. Thus, a phase difference can be obtained for a greater number of receiving antenna combinations.

[0072] In addition, according to the first embodiment, phase compensation between receiving circuits includes performing phase compensation according to the phase difference between the received signals acquired in each overlap mode with different center frequencies. Therefore, phase compensation between receiving circuits can be performed based on information of multiple phase differences. Consequently, the accuracy of phase compensation can be improved.

[0073] Furthermore, according to the first embodiment, the receiving antennas in the receiving antenna system 3 are arranged alternately at equal intervals, and the transmitting antennas in the transmitting antenna system 2 are arranged at intervals that are even multiples of the intervals in the receiving antennas. Therefore, by switching the center frequency, it is possible to reliably switch between overlap mode and non-overlap mode.

[0074] Furthermore, according to the first embodiment, the overlap mode and non-overlap mode are switched over in time. Therefore, in the radar device 1, phase compensation between receiving circuits can be performed periodically.

[0075] (Other embodiments) Although several embodiments have been described above, this disclosure is not limited to those embodiments and can be applied to various embodiments and combinations without departing from the spirit of this disclosure.

[0076] In the modified example, the radar device 1 may have only one overlap mode. For example, the radar device 1 may be configured to switch between a non-overlap mode at a low center frequency and an overlap mode at a high center frequency.

[0077] In the modified configuration, the transmitting antennas 20a, 20b and receiving antennas 30a, 30b may be arranged in patterns other than those shown in Figure 5, provided that the antenna positions of different receiving circuits 53 virtually overlap in overlap mode. In this case, whether the overlap mode and non-overlap mode are realized at their respective center frequencies is not limited to the configuration of the first embodiment.

[0078] In the modified example, the dedicated computer constituting the controller 6 may have at least one of the digital circuit and analog circuit as a processor. Here, the digital circuit is at least one of the following, for example, 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.

[0079] In the modified example, the mobile body to which the radar device 1 is applied may be, for example, an autonomous mobile robot capable of transporting goods or collecting information 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, etc.) or a semiconductor device (e.g., a semiconductor chip, etc.) as a control device configured to be mounted on a host mobile body and having at least one processor 3b and one memory 3a.

[0080] (Note) This specification discloses several technical concepts and several combinations thereof, as listed below.

[0081] (Technical thought 1) A transmitting antenna system (2) comprising multiple transmitting antenna units (TX1, TX2) including a pair of transmitting antennas (20a, 20b) with different peak gain frequencies, A receiving antenna system (3) includes multiple receiving antenna units (RX1, RX2, RX3, RX4) which include a set of receiving antennas (30a, 30b) with different peak frequencies, A control unit (6) controls the operation of a transmitting circuit (50) that generates a transmitting signal transmitted from the transmitting antenna system, and a plurality of receiving circuits (53) that process the received signal received by the receiving antenna system. Equipped with, The control unit is By changing the center frequency of the transmitted signal, the system switches between an overlap mode, which allows for a virtual overlap of the positions of the receiving antennas connected to different receiving circuits due to a phase difference corresponding to the spacing between the transmitting antennas in each transmitting antenna unit, and a non-overlap mode, which prohibits such virtual overlap of positions. In the overlap mode, phase compensation is performed between the receiving circuits according to the phase difference between the received signals received by the receiving antennas whose positions overlap. A radar device configured to perform the following actions.

[0082] (Technical thought 2) The control unit is Switching between the overlap mode and the non-overlap mode, A radar device according to technical concept 1, which includes switching the center frequency between a high center frequency, which is the center frequency corresponding to the transmitting antenna with a high peak frequency among the set of transmitting antennas, and a low center frequency, which is the center frequency corresponding to the transmitting antenna with a low peak frequency.

[0083] (Technical Thought 3) The control unit is Switching between the overlap mode and the non-overlap mode, A radar device according to technical concept 2, which includes switching the center frequency between the high center frequency, the low center frequency, and an intermediate center frequency included in the frequency range from the high center frequency to the low center frequency, thereby switching between a plurality of overlap modes with different center frequencies and the non-overlap mode with the remaining center frequencies.

[0084] (Technical Thought 4) The control unit is To perform phase compensation between the aforementioned receiving circuits, A radar device according to technical concept 3, which includes performing phase compensation according to the phase difference between the received signals acquired in each of the overlap modes with different center frequencies.

[0085] (Technical Thought 5) The receiving antennas in the receiving antenna system are arranged alternately at equal intervals. The radar device according to any one of Technical Concepts 1 to 4, wherein the transmitting antennas in the transmitting antenna system are arranged at intervals that are even multiples of the intervals in the receiving antennas.

[0086] (Technical Thought 6) The control unit is a radar device according to any one of Technical Concepts 1 to 5 that temporally switches between the overlap mode and the non-overlap mode. [Explanation of symbols]

[0087] 1: Radar device, 2: Transmitting antenna system, 20a, 20b: Transmitting antenna, 3: Receiving antenna system, 30a, 30b: Receiving antenna, 5: Transmitting / receiving unit, 6: Controller (control unit), 50: Transmitting circuit, 53: Receiving circuit, 6: Controller, TX1, TX2: Transmitting antenna unit, RX1, RX2, RX3, RX4: Receiving antenna unit

Claims

1. A transmitting antenna system (2) comprising multiple transmitting antenna units (TX1, TX2) including a pair of transmitting antennas (20a, 20b) with different peak gain frequencies, A receiving antenna system (3) comprising multiple receiving antenna units (RX1, RX2, RX3, RX4) including a set of receiving antennas (30a, 30b) with different peak frequencies, A control unit (6) controls the operation of a transmitting circuit (50) that generates a transmitting signal transmitted from the transmitting antenna system, and a plurality of receiving circuits (53) that process the received signal received by the receiving antenna system. Equipped with, The control unit is By changing the center frequency of the transmitted signal, the system switches between an overlap mode, which allows for a virtual overlap of the positions of the receiving antennas connected to different receiving circuits due to a phase difference corresponding to the spacing between the transmitting antennas in each transmitting antenna unit, and a non-overlap mode, which prohibits such virtual overlap of positions. In the overlap mode, phase compensation is performed between the receiving circuits according to the phase difference between the received signals received by the receiving antennas whose positions overlap. It is configured to perform, Switching between the overlap mode and the non-overlap mode, The center frequency is switched between a high center frequency, which corresponds to the center frequency of the transmitting antenna with a high peak frequency among the set of transmitting antennas, and a low center frequency, which corresponds to the center frequency of the transmitting antenna with a low peak frequency. By switching the center frequency between the high center frequency, the low center frequency, and the intermediate center frequency included in the frequency range from the high center frequency to the low center frequency, it is possible to switch between multiple overlap modes with different center frequencies and the non-overlapping mode with the remaining center frequency. Radar equipment including [unclear / unclear].

2. The control unit is To perform phase compensation between the aforementioned receiving circuits, The radar device according to claim 1, further comprising performing phase compensation according to the phase difference between the received signals acquired in each of the overlap modes with different center frequencies.

3. The receiving antennas in the receiving antenna system are arranged alternately at equal intervals. The radar device according to claim 1, wherein the transmitting antennas in the transmitting antenna system are arranged at intervals that are an even multiple of the intervals between the receiving antennas.

4. The radar device according to claim 1, wherein the control unit switches between the overlap mode and the non-overlap mode in a time interval.

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