Electronic device, method for controlling an electronic device, and program

Abstract

To provide an electronic apparatus, a method for controlling an electronic apparatus, and a program that contribute to an improvement in the accuracy of detecting an object.SOLUTION: An electronic apparatus comprises: a transmission antenna that transmits a transmission wave; a reception antenna that receives a reflected wave being the reflected transmission wave; and a signal processing unit that calculates the distance and relative velocity between an object reflecting the transmission wave and the apparatus based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave. The signal processing unit composes the distance and relative velocity according to the composite number set as the number of times to compose the reception signals.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an electronic device, a control method for an electronic device, and a program.

Background Art

[0002] For example, in fields such as industries related to automobiles, technologies for measuring the distance between a host vehicle and a predetermined object are regarded as important. In particular, in recent years, technologies for radar (Radio Detecting and Ranging) that measure the distance to an object by transmitting radio waves such as millimeter waves and receiving reflected waves reflected by an object such as an obstacle have been variously studied. The importance of such technologies for measuring distances and the like is expected to increase further in the future with the development of technologies for assisting a driver's driving and technologies related to autonomous driving that automate part or all of the driving.

[0003] In addition, several proposals have been made for technologies that can improve the accuracy of detecting the presence of an object by receiving a reflected wave obtained by reflecting a transmitted radio wave from a predetermined object. For example, Patent Document 1 proposes amplifying a component of a light reception signal corresponding to a reflected wave from a reflecting object by integrating a predetermined number of light reception signals output based on a predetermined number of laser lights, thereby improving the detection sensitivity of the reflected wave from the reflecting object. Further, Patent Document 2 discloses a radar device that can accurately measure the distance to a reflecting object by quickly responding to changes even when the relative speed of the reflecting object increases.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a technique of detecting an object by receiving a reflected wave obtained by reflecting a transmission wave from a predetermined object, it is desirable to improve the detection accuracy.

[0006] An object of the present disclosure is to provide an electronic device, a control method for an electronic device, and a program that contribute to improving the accuracy of detecting an object.

Means for Solving the Problems

[0007] An electronic device according to an embodiment includes: a transmission antenna that transmits a transmission wave; a reception antenna that receives a reflected wave obtained by reflecting the transmission wave; a signal processing unit that calculates a distance and a relative speed between an object that reflects the transmission wave and the own device based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave; and is provided with. The signal processing unit synthesizes the distance and the relative speed according to the number of syntheses set as the number of times of synthesizing the reception signal. The synthetic number is a number that increases as the range resolution in the signal processing unit increases and decreases as the velocity resolution in the signal processing unit increases.

[0008] A control method for an electronic device according to an embodiment includes: a step of transmitting a transmission wave; a step of receiving a reflected wave obtained by reflecting the transmission wave; a step of calculating a distance and a relative speed between an object that reflects the transmission wave and the own device based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave; a step of synthesizing the distance and the relative speed according to the number of syntheses set as the number of times of synthesizing the reception signal; and includes. The synthetic number is a number that increases as the range resolution in the calculating step increases and decreases as the velocity resolution in the calculating step increases.

[0009] A program according to an embodiment causes an electronic device to perform a step of transmitting a transmission wave; a step of transmitting a transmission wave; The step of receiving a reflected wave obtained by reflecting the transmission wave; Based on the transmission signal transmitted as the transmission wave and the reception signal received as the reflected wave, calculating the distance and relative velocity between the object that reflects the transmission wave and the own device; Based on the number of syntheses set as the number of times of synthesizing the reception signals, synthesizing the distance and the relative velocity; Execute. The synthetic number is a number that increases as the range resolution in the calculating step increases and decreases as the velocity resolution in the calculating step increases.

Advantages of the Invention

[0010] According to one embodiment, it is possible to provide an electronic device, a control method for an electronic device, and a program that contribute to improving the accuracy of detecting an object.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0012] Hereinafter, an embodiment will be described in detail with reference to the drawings.

[0013] In the present disclosure, the "electronic device" may be, for example, a device driven by electric power supplied from an electric power system or a battery. In the present disclosure, the "user" may be a person who uses or can use the electronic device according to one embodiment (typically a human), and a person who uses or can use a system including the electronic device according to one embodiment.

[0014] The electronic device according to one embodiment can detect a predetermined object existing around the moving body by being mounted on a moving body (a vehicle) such as an automobile. For this purpose, the electronic device according to one embodiment can transmit a transmission wave from a transmission antenna installed on the moving body to the surroundings of the moving body. Further, the electronic device according to one embodiment can receive a reflected wave obtained by reflecting the transmission wave from a reception antenna installed on the moving body. At least one of the transmission antenna and the reception antenna may be provided in, for example, a radar sensor installed on the moving body.

[0015] Hereinafter, as a typical example, a configuration in which an electronic device according to an embodiment is mounted on an automobile such as a passenger car will be described. However, the electronic device according to an embodiment is not limited to being mounted on an automobile. The electronic device according to an embodiment may be mounted on various moving bodies such as a self-driving automobile, a bus, a truck, a taxi, a motorcycle, a bicycle, a ship, an airplane, a helicopter, an agricultural working device such as a tractor, a snowplow, a cleaning vehicle, a police car, an ambulance, and a drone. Further, the electronic device according to an embodiment is not necessarily limited to a moving body that moves by its own power. For example, the moving body on which the electronic device according to an embodiment is mounted may be a trailer portion towed by a tractor. The electronic device according to an embodiment can measure the distance between a sensor and an object, etc. in a situation where at least one of the sensor and a predetermined object can move. Further, the electronic device according to an embodiment can measure the distance between the sensor and the object, etc. even when both the sensor and the object are stationary. Also, the automobiles included in the present disclosure are not limited by the overall length, overall width, overall height, displacement, seating capacity, or loading capacity, etc. For example, the automobiles of the present disclosure include automobiles with a displacement greater than 660 cc and automobiles with a displacement of 660 cc or less, so-called light automobiles. Also, the automobiles included in the present disclosure include automobiles that use electricity for part or all of the energy and use a motor.

[0016] First, an example of object detection by an electronic device according to an embodiment will be described.

[0017] FIG. 1 is a diagram for explaining a usage mode of an electronic device according to an embodiment. FIG. 1 shows an example in which a sensor including a transmission antenna and a reception antenna according to an embodiment is installed on a moving body.

[0018] As shown in FIG. 1, a sensor 5 including a transmission antenna and a reception antenna according to an embodiment is installed in the moving body 100. Also, it is assumed that the moving body 100 shown in FIG. 1 is equipped (for example, built-in) with an electronic device 1 according to an embodiment. The specific configuration of the electronic device 1 will be described later. The sensor 5 may include, for example, at least one of a transmission antenna and a reception antenna. Further, the sensor 5 may appropriately include at least any one of other functional parts, such as at least a part of a control unit 10 (see FIG. 2) included in the electronic device 1. The moving body 100 shown in FIG. 1 may be a vehicle such as a passenger car, but may be any type of moving body. In FIG. 1, the moving body 100 may be moving (traveling or creeping) in the positive Y-axis direction (traveling direction) shown in the figure, may be moving in other directions, or may be stationary without moving.

[0019] As shown in FIG. 1, a sensor 5 including a transmission antenna is installed in the moving body 100. In the example shown in FIG. 1, only one sensor 5 including a transmission antenna and a reception antenna is installed in front of the moving body 100. Here, the position where the sensor 5 is installed in the moving body 100 is not limited to the position shown in FIG. 1, and may be other positions as appropriate. For example, the sensor 5 as shown in FIG. 1 may be installed on the left side, right side, and / or rear of the moving body 100. Also, the number of such sensors 5 may be any number of one or more according to various conditions (or requirements) such as the measurement range and / or accuracy in the moving body 100. The sensor 5 may be installed inside the moving body 100. The inside of the moving body 100 may be, for example, the space inside the bumper, the space inside the body, the space inside the headlight, or the space of the driving space.

[0020] The sensor 5 transmits electromagnetic waves as transmission waves from the transmission antenna. For example, when a predetermined object (e.g., the object 200 shown in FIG. 1) exists around the moving body 100, at least a part of the transmission waves transmitted from the sensor 5 is reflected by the object to become reflected waves. Then, by receiving such reflected waves with, for example, the receiving antenna of the sensor 5, the electronic device 1 mounted on the moving body 100 can detect the object as a target.

[0021] The sensor 5 provided with the transmission antenna may typically be a radar (Radio Detecting and Ranging) sensor that transmits and receives radio waves. However, the sensor 5 is not limited to a radar sensor. The sensor 5 according to one embodiment may be a sensor based on, for example, the technology of LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) using light waves. Such sensors can be configured to include, for example, patch antennas. Since technologies such as RADAR and LIDAR are already known, detailed descriptions may be appropriately simplified or omitted.

[0022] The electronic device 1 mounted on the moving body 100 shown in FIG. 1 receives the reflected waves of the transmission waves transmitted from the transmission antenna of the sensor 5 from the receiving antenna. In this way, the electronic device 1 can detect a predetermined object 200 existing within a predetermined distance from the moving body 100 as a target. For example, as shown in FIG. 1, the electronic device 1 can measure (estimate) the distance A between the moving body 100, which is the host vehicle, and the predetermined object 200. In addition, the electronic device 1 can also measure (estimate) the relative speed between the moving body 100, which is the host vehicle, and the predetermined object 200. Furthermore, the electronic device 1 can also measure (estimate) the direction (arrival angle θ) in which the reflected waves from the predetermined object 200 arrive at the moving body 100, which is the host vehicle.

[0023] Here, the object 200 may be, for example, at least any one of an oncoming vehicle traveling in a lane adjacent to the moving body 100, an automobile traveling parallel to the moving body 100, and automobiles in front of and behind the moving body 100 traveling in the same lane. Further, the object 200 may be any object existing around the moving body 100, such as a motorcycle, a bicycle, a baby stroller, a human such as a pedestrian, an animal, an insect, or other living organisms, a guardrail, a median strip, a road sign, a step of a sidewalk, a wall, a manhole, or an obstacle. Furthermore, the object 200 may be moving or stationary. For example, the object 200 may be an automobile parked or stopped around the moving body 100. In the present disclosure, the object detected by the sensor 5 includes not only inanimate objects but also living organisms such as humans or animals. The object detected by the sensor 5 of the present disclosure includes object targets including humans, objects, and animals detected by radar technology.

[0024] In FIG. 1, the ratio between the size of the sensor 5 and the size of the moving body 100 does not necessarily indicate the actual ratio. Also, in FIG. 1, the sensor 5 is shown in a state of being installed outside the moving body 100. However, in one embodiment, the sensor 5 may be installed at various positions of the moving body 100. For example, in one embodiment, the sensor 5 may be installed inside the bumper of the moving body 100 so as not to appear on the exterior of the moving body 100.

[0025] Hereinafter, as a typical example, the transmission antenna of the sensor 5 will be described as transmitting radio waves in a frequency band such as millimeter waves (30 GHz or higher) or quasi-millimeter waves (for example, around 20 GHz to 30 GHz). For example, the transmission antenna of the sensor 5 may transmit radio waves having a frequency bandwidth of 4 GHz, such as 77 GHz to 81 GHz.

[0026] FIG. 2 is a functional block diagram schematically showing a configuration example of the electronic device 1 according to one embodiment. Hereinafter, an example of the configuration of the electronic device 1 according to one embodiment will be described.

[0027] When measuring distance or the like using a millimeter-wave radar, a frequency-modulated continuous-wave radar (hereinafter referred to as an FMCW radar (Frequency Modulated Continuous Wave radar)) is often used. In an FMCW radar, a transmission signal is generated by sweeping the frequency of the radio wave to be transmitted. Therefore, for example, in a millimeter-wave FMCW radar using radio waves in the 79 GHz frequency band, the frequency of the radio waves to be used has a frequency bandwidth of 4 GHz, such as 77 GHz to 81 GHz. The radar in the 79 GHz frequency band has a characteristic that the available frequency bandwidth is wider than that of other millimeter-wave / sub-millimeter-wave radars, such as those in the 24 GHz and 76 GHz frequency bands. Hereinafter, as an example, such an embodiment will be described.

[0028] As shown in FIG. 2, the electronic device 1 according to an embodiment may be composed of a sensor 5 and an ECU (Electronic Control Unit) 50. The ECU 50 controls various operations of the mobile body 100. The ECU 50 may be composed of at least one or more ECUs. The electronic device 1 according to an embodiment may include a control unit 10. Further, the electronic device 1 according to an embodiment may appropriately include other functional units, such as at least one of a transmission unit 20 and reception units 30A to 30D. Furthermore, the electronic device 1 according to an embodiment may include a signal processing unit 40. As shown in FIG. 2, the electronic device 1 may include a plurality of reception units, such as reception units 30A to 30D. Hereinafter, when the reception unit 30A, the reception unit 30B, the reception unit 30C, and the reception unit 30D are not distinguished, they are simply referred to as "reception unit 30".

[0029] FIG. 3 is a block diagram schematically showing the functions of the control unit 10 shown in FIG. 2. As shown in FIG. 3, the control unit 10 may include a mode selection unit 11 and a parameter setting unit 12. These functional units included in the control unit 10 will be further described later.

[0030] FIG. 4 is a block diagram schematically showing the functions of the signal processing unit 40 shown in FIG. 2. As shown in FIG. 4, the signal processing unit 40 may include a distance FFT processing unit 41, a velocity FFT processing unit 42, a synthesizing unit 43, a synthesis number storage unit 44, a threshold determination unit 45, an arrival angle estimation unit 46, an object detection unit 47, and an output determination unit 48. These functional units included in the signal processing unit 40 will be described in further detail below.

[0031] As shown in FIG. 2, the transmission unit 20 may include a signal generation unit 21, a synthesizer 22, phase control units 23A and 23B, amplifiers 24A and 24B, and transmission antennas 25A and 25B. Hereinafter, when the phase control unit 23A and the phase control unit 23B are not distinguished, they are simply referred to as "phase control unit 23". Also, hereinafter, when the amplifier 24A and the amplifier 24B are not distinguished, they are simply referred to as "amplifier 24". Also, hereinafter, when the transmission antenna 25A and the transmission antenna 25B are not distinguished, they are simply referred to as "transmission antenna 25".

[0032] As shown in FIG. 2, the reception unit 30 may include corresponding reception antennas 31A to 31D. Hereinafter, when the reception antenna 31A, the reception antenna 31B, the reception antenna 31C, and the reception antenna 31D are not distinguished, they are simply referred to as "reception antenna 31". Also, each of the plurality of reception units 30 may include an LNA 32, a mixer 33, an IF unit 34, and an AD conversion unit 35, as shown in FIG. 2. The reception units 30A to 30D may each have the same configuration. In FIG. 2, as a representative example, only the configuration of the reception unit 30A is schematically shown.

[0033] The above-described sensor 5 may include, for example, the transmission antenna 25 and the reception antenna 31. The sensor 5 may also appropriately include at least any one of other functional units such as the control unit 10 and the signal processing unit 40.

[0034] The control unit 10 included in the electronic device 1 according to one embodiment can control the operation of the entire electronic device 1, including the control of each functional unit constituting the electronic device 1. In order to provide control and / or processing capabilities for executing various functions, the control unit 10 may include at least one processor, such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The control unit 10 may be realized by a single processor, may be realized by several processors, or may be realized by individual processors respectively. The processor may be realized as a single integrated circuit. The integrated circuit is also called an IC (Integrated Circuit). The processor may be realized as a plurality of communicably connected integrated circuits and discrete circuits. The processor may be realized based on various other known technologies. In one embodiment, the control unit 10 may be configured as, for example, a CPU (hardware) and a program (software) executed by the CPU. The control unit 10 may appropriately include a memory necessary for the operation of the control unit 10.

[0035] In the electronic device 1 according to one embodiment, the control unit 10 may control at least one of the transmission unit 20 and the reception unit 30. In this case, the control unit 10 may control at least one of the transmission unit 20 and the reception unit 30 based on various information stored in an arbitrary storage unit (memory). Also, in the electronic device 1 according to one embodiment, the control unit 10 may instruct the signal generation unit 21 to generate a signal or control the signal generation unit 21 to generate a signal.

[0036] In the control unit 10 shown in FIG. 3, the mode selection unit 11 selects the operation mode of the electronic device 1. In one embodiment, the mode selection unit 11 may select the radar mode as the operation mode of the electronic device 1. The radar mode selected by the mode selection unit 11 will be described in further detail later. The operation mode of the electronic device 1 selected by the mode selection unit 11 may be transmitted to the parameter setting unit 12 and the signal processing unit 40. In one embodiment, the operation mode of the electronic device 1 selected by the mode selection unit 11 may be transmitted to the composite number storage unit 44 (see FIG. 3) of the signal processing unit 40. As will be described later, the mode selection unit 11 may store information regarding the composite number corresponding to the selected operation mode of the electronic device 1 (for example, a table indicating the number of composite times) in the composite number storage unit 44.

[0037] In the control unit 10 shown in FIG. 3, the parameter setting unit 12 sets various parameters corresponding to the operation mode of the electronic device 1 selected by the mode selection unit 11. In one embodiment, the parameter setting unit 12 may set various radar parameters corresponding to the radar mode as parameters corresponding to the operation of the electronic device 1. The parameters set by the parameter setting unit 12 may be stored in an arbitrary storage unit in advance, or may be acquired by, for example, communication. The parameters set by the parameter setting unit 12 will be described in further detail later. The parameters set by the parameter setting unit 12 may be transmitted to the transmission unit 20. In one embodiment, the parameters set by the parameter setting unit 12 may be transmitted to the signal generation unit 21 (see FIG. 3) of the transmission unit 20. The signal generation unit 21 of the transmission unit 20 generates a transmission signal (transmission wave) transmitted from the electronic device 1 based on the parameters transmitted from the parameter setting unit 12.

[0038] The signal generation unit 21 generates a signal (transmission signal) transmitted as a transmission wave T from the transmission antenna 25 under the control of the control unit 10. As described above, the signal generation unit 21 may generate a transmission signal based on various parameters transmitted from the parameter setting unit 12. Specifically, when generating a transmission signal, the signal generation unit 21 may assign the frequency of the transmission signal based on, for example, the parameters set by the parameter setting unit 12. Also, the signal generation unit 21 may assign the frequency of the transmission signal according to, for example, the parameters set by the parameter setting unit 12. For example, the signal generation unit 21 receives frequency information from the control unit 10 or an arbitrary storage unit (memory) to generate a signal having a predetermined frequency in a frequency band such as 77 to 81 GHz. The signal generation unit 21 may be configured to include a functional unit such as, for example, a voltage controlled oscillator (VCO).

[0039] The signal generation unit 21 may be configured as hardware having the said function, or may be configured by, for example, a microcomputer, or may be configured as, for example, a processor such as a CPU and a program executed by the said processor. Each of the functional units described below may also be configured as hardware having the said function, or, if possible, may be configured by, for example, a microcomputer, or may be configured as, for example, a processor such as a CPU and a program executed by the said processor.

[0040] In the electronic device 1 according to an embodiment, the signal generation unit 21 may generate a transmission signal (transmission chirp signal) such as a chirp signal. In particular, the signal generation unit 21 may generate a signal whose frequency linearly changes periodically (linear chirp signal). For example, the signal generation unit 21 may generate a chirp signal whose frequency periodically and linearly increases from 77 GHz to 81 GHz as time elapses. Also, for example, the signal generation unit 21 may generate a signal whose frequency periodically repeats linear increase (up-chirp) and decrease (down-chirp) from 77 GHz to 81 GHz as time elapses. The signal generated by the signal generation unit 21 may be preset in the control unit 10 (parameter setting unit 12), for example. Also, the signal generated by the signal generation unit 21 may be prestored in an arbitrary storage unit (memory) or the like, for example. Since the chirp signal used in the technical field such as radar is known, more detailed description will be appropriately simplified or omitted. The signal generated by the signal generation unit 21 is supplied to the synthesizer 22.

[0041] FIG. 5 is a diagram for explaining an example of the chirp signal generated by the signal generation unit 21.

[0042] In FIG. 5, the horizontal axis represents the elapsed time, and the vertical axis represents the frequency. In the example shown in FIG. 5, the signal generation unit 21 generates a linear chirp signal whose frequency linearly changes periodically. In FIG. 5, each chirp signal is shown as c1, c2,..., c8. As shown in FIG. 5, in each chirp signal, the frequency linearly increases as time elapses.

[0043] In the example shown in FIG. 5, including eight chirp signals such as c1, c2, …, c8, it is regarded as one subframe. That is, subframe 1 and subframe 2 shown in FIG. 5, etc., are each composed of including eight chirp signals such as c1, c2, …, c8. Also, in the example shown in FIG. 5, including 16 subframes such as subframe 1 to subframe 16, it is regarded as one frame. That is, frame 1 and frame 2 shown in FIG. 5, etc., are each composed of including 16 subframes. Also, as shown in FIG. 5, between frames, a frame interval of a predetermined length may be included. One frame shown in FIG. 5 may have a length of about 30 milliseconds to 50 milliseconds, for example.

[0044] In FIG. 5, the subsequent frames such as frame 2 may have the same configuration. Also, in FIG. 5, the subsequent frames such as frame 3 may have the same configuration. In the electronic device 1 according to an embodiment, the signal generation unit 21 may generate a transmission signal as any number of frames. Also, in FIG. 5, some of the chirp signals are shown omitted. Thus, the relationship between the time and frequency of the transmission signal generated by the signal generation unit 21 may be set by, for example, the parameter setting unit 12, or may be stored in an arbitrary storage unit (memory), etc.

[0045] Thus, the electronic device 1 according to an embodiment may transmit a transmission signal composed of subframes including a plurality of chirp signals. Also, the electronic device 1 according to an embodiment may transmit a transmission signal composed of frames including a predetermined number of subframes.

[0046] Hereinafter, the electronic device 1 will be described as transmitting a transmission signal having a frame structure as shown in FIG. 5. However, the frame structure as shown in FIG. 5 is an example, and for example, the number of chirp signals included in one sub-frame is not limited to eight. In one embodiment, the signal generation unit 21 may generate a sub-frame including an arbitrary number (for example, an arbitrary plurality) of chirp signals. Also, the sub-frame structure as shown in FIG. 5 is an example, and for example, the number of sub-frames included in one frame is not limited to 16. In one embodiment, the signal generation unit 21 may generate a frame including an arbitrary number (for example, an arbitrary plurality) of sub-frames. The signal generation unit 21 may generate signals having different frequencies. The signal generation unit 21 may generate a plurality of discrete signals having different bandwidths with different frequencies f respectively.

[0047] Returning to FIG. 2, the synthesizer 22 raises the frequency of the signal generated by the signal generation unit 21 to the frequency in a predetermined frequency band. The synthesizer 22 may raise the frequency of the signal generated by the signal generation unit 21 to the frequency selected as the frequency of the transmission wave T transmitted from the transmission antenna 25. The frequency selected as the frequency of the transmission wave T transmitted from the transmission antenna 25 may be set by, for example, the control unit 10 (parameter setting unit 12). Also, the frequency selected as the frequency of the transmission wave T transmitted from the transmission antenna 25 may be stored in, for example, an arbitrary storage unit (memory). The signal whose frequency has been raised by the synthesizer 22 is supplied to the phase control unit 23 and the mixer 33. When there are a plurality of phase control units 23, the signal whose frequency has been raised by the synthesizer 22 may be supplied to each of the plurality of phase control units 23. Also, when there are a plurality of reception units 30, the signal whose frequency has been raised by the synthesizer 22 may be supplied to each mixer 33 in the plurality of reception units 30.

[0048] The phase control unit 23 controls the phase of the transmission signal supplied from the synthesizer 22. Specifically, the phase control unit 23 may adjust the phase of the transmission signal by advancing or delaying the phase of the signal supplied from the synthesizer 22 as appropriate based on, for example, the control by the control unit 10. In this case, the phase control unit 23 may adjust the phase of each transmission signal based on the path difference of each transmission wave T transmitted from the plurality of transmission antennas 25. By appropriately adjusting the phase of each transmission signal by the phase control unit 23, the transmission waves T transmitted from the plurality of transmission antennas 25 reinforce each other in a predetermined direction to form a beam (beamforming). In this case, the correlation between the direction of beamforming and the phase amount to be controlled of the transmission signals transmitted by the plurality of transmission antennas 25 may be stored in, for example, an arbitrary storage unit (memory). The transmission signal whose phase is controlled by the phase control unit 23 is supplied to the amplifier 24.

[0049] The amplifier 24 amplifies the power (electric power) of the transmission signal supplied from the phase control unit 23 based on, for example, the control by the control unit 10. When the sensor 5 includes a plurality of transmission antennas 25, the plurality of amplifiers 24 may each amplify the power (electric power) of the transmission signal supplied from the corresponding one of the plurality of phase control units 23 based on, for example, the control by the control unit 10. Since the technology of amplifying the power of the transmission signal itself is already known, a more detailed description is omitted. The amplifier 24 is connected to the transmission antenna 25.

[0050] The transmission antenna 25 outputs (transmits) the transmission signal amplified by the amplifier 24 as the transmission wave T. When the sensor 5 includes a plurality of transmission antennas 25, the plurality of transmission antennas 25 may each output (transmit) the transmission signal amplified by the corresponding one of the plurality of amplifiers 24 as the transmission wave T. Since the transmission antenna 25 can be configured in the same manner as the transmission antenna used in known radar technology, a more detailed description is omitted.

[0051] In this way, the electronic device 1 according to one embodiment includes a transmission antenna 25 and can transmit a transmission signal (for example, a transmission chirp signal) as a transmission wave T from the transmission antenna 25. Here, at least one of the functional units constituting the electronic device 1 may be housed in one housing. Also, in this case, the one housing may have a structure that cannot be easily opened. For example, it is preferable that the transmission antenna 25, the reception antenna 31, and the amplifier 24 are housed in one housing and this housing has a structure that cannot be easily opened. Further, here, when the sensor 5 is installed in a moving body 100 such as an automobile, the transmission antenna 25 may transmit the transmission wave T to the outside of the moving body 100 via a cover member such as a radar cover. In this case, the radar cover may be made of a material that allows electromagnetic waves to pass through, such as synthetic resin or rubber. This radar cover may be, for example, the housing of the sensor 5. By covering the transmission antenna 25 with a member such as a radar cover, the risk that the transmission antenna 25 is damaged or malfunction occurs due to contact with the outside can be reduced. Also, the above-mentioned radar cover and housing are sometimes also called a radome.

[0052] The electronic device 1 shown in FIG. 2 shows an example of including two transmission antennas 25. However, in one embodiment, the electronic device 1 may include any number of transmission antennas 25. On the other hand, in one embodiment, when the transmission wave T transmitted from the transmission antenna 25 forms a beam in a predetermined direction, the electronic device 1 may include a plurality of transmission antennas 25. In one embodiment, the electronic device 1 may include any plurality of transmission antennas 25. In this case, the electronic device 1 may also include a plurality of phase control units 23 and amplifiers 24 corresponding to the plurality of transmission antennas 25, respectively. Then, the plurality of phase control units 23 may control the phases of the plurality of transmission waves supplied from the synthesizer 22 and transmitted from the plurality of transmission antennas 25, respectively. Also, the plurality of amplifiers 24 may amplify the powers of the plurality of transmission signals transmitted from the plurality of transmission antennas 25, respectively. Also, in this case, the sensor 5 may be configured to include a plurality of transmission antennas. As described above, when the electronic device 1 shown in FIG. 2 includes a plurality of transmission antennas 25, the electronic device 1 may also include a plurality of functional units necessary for transmitting the transmission wave T from the plurality of transmission antennas 25, respectively.

[0053] The receiving antenna 31 receives the reflected wave R. The reflected wave R may be the one obtained by reflecting the transmission wave T on a predetermined object 200. The receiving antenna 31 may be configured to include a plurality of antennas, such as the receiving antennas 31A to 31D, for example. Since the receiving antenna 31 can be configured in the same manner as the receiving antenna used in the known radar technology, a more detailed description is omitted. The receiving antenna 31 is connected to the LNA 32. The received signal based on the reflected wave R received by the receiving antenna 31 is supplied to the LNA 32.

[0054] An electronic device 1 according to an embodiment can receive a reflected wave R obtained by reflecting a transmitted wave T transmitted as a transmission signal (transmission chirp signal), such as a chirp signal, from a plurality of receiving antennas 31 by a predetermined object 200. As described above, when transmitting a transmission chirp signal as the transmitted wave T, a reception signal based on the received reflected wave R is referred to as a reception chirp signal. That is, the electronic device 1 receives a reception signal (for example, a reception chirp signal) as the reflected wave R from the receiving antenna 31. Here, when the sensor 5 is installed in a moving body 100 such as an automobile, the receiving antenna 31 may receive the reflected wave R from the outside of the moving body 100 via a cover member such as a radar cover. In this case, the radar cover may be made of a material that allows electromagnetic waves to pass through, such as synthetic resin or rubber. This radar cover may also be, for example, the housing of the sensor 5. By covering the receiving antenna 31 with a member such as a radar cover, the risk of damage or malfunction of the receiving antenna 31 due to contact with the outside can be reduced. Further, the radar cover and the housing may also be referred to as a radome.

[0055] Further, for example, when the antenna 31 is installed near the transmitting antenna 25, they may be collectively included in one sensor 5. That is, one sensor 5 may include, for example, at least one transmitting antenna 25 and at least one receiving antenna 31. For example, one sensor 5 may include a plurality of transmitting antennas 25 and a plurality of receiving antennas 31. In such a case, for example, a cover member such as one radar cover may be used to cover one radar sensor.

[0056] The LNA 32 amplifies a reception signal based on the reflected wave R received by the receiving antenna 31 with low noise. The LNA 32 may be a low noise amplifier and amplifies the reception signal supplied from the receiving antenna 31 with low noise. The reception signal amplified by the LNA 32 is supplied to the mixer 33.

[0057] The mixer 33 generates a beat signal by mixing (multiplying) the received signal at RF frequency supplied from the LNA 32 with the transmission signal supplied from the synthesizer 22. The beat signal mixed by the mixer 33 is supplied to the IF section 34.

[0058] The IF section 34 performs frequency conversion on the beat signal supplied from the mixer 33 to lower the frequency of the beat signal to the intermediate frequency (IF). The beat signal whose frequency has been lowered by the IF section 34 is supplied to the AD conversion section 35.

[0059] The AD conversion section 35 digitizes the analog beat signal supplied from the IF section 34. The AD conversion section 35 may be constituted by any analog-to-digital conversion circuit (Analog to Digital Converter (ADC)). The beat signal digitized by the AD conversion section 35 may be supplied to the signal processing section 40. More specifically, the beat signal digitized by the AD conversion section 35 may be supplied to the distance FFT processing section 41 (see FIG. 4) of the signal processing section 40. When there are a plurality of receiving sections 30, each of the beat signals digitized by the plurality of AD conversion sections 35 may be supplied to the distance FFT processing section 41 of the signal processing section 40.

[0060] The signal processing section 40 included in the electronic device 1 according to one embodiment may perform various signal processes on the signal (received signal) output from the receiving section 30. The signal processing section 40 may include at least one processor such as a CPU or a DSP in order to provide control and / or processing capabilities for executing various functions including signal processing. The signal processing section 40 may be realized by one processor collectively, or by several processors, or by individual processors respectively. In one embodiment, the signal processing section 40 may be constituted by, for example, a CPU (hardware) and a program (software) executed by the CPU. The signal processing section 40 may appropriately include a memory necessary for the operation of the signal processing section 40.

[0061] In the signal processing unit 40 shown in FIG. 4, the distance FFT processing unit 41 estimates the distance between the moving body 100 on which the electronic device 1 is mounted and the object 200 based on the beat signal supplied from the AD conversion unit 35. The distance FFT processing unit 41 may include, for example, a processing unit that performs a fast Fourier transform. In this case, the distance FFT processing unit 41 may be configured by any circuit or chip that performs a fast Fourier transform (FFT) process.

[0062] The distance FFT processing unit 41 performs an FFT process on the beat signal digitized by the AD conversion unit 35 of the receiving unit 30 (hereinafter, appropriately referred to as "distance FFT processing"). The distance FFT processing is also referred to as 1D FFT processing. For example, the distance FFT processing unit 41 may perform an FFT process on the complex signal supplied from the AD conversion unit 35. The beat signal digitized by the AD conversion unit 35 can be represented as a time change in signal intensity (power). By performing an FFT process on such a beat signal, the distance FFT processing unit 41 can represent it as the signal intensity (power) corresponding to each frequency. When the peak in the result obtained by the distance FFT processing is equal to or greater than a predetermined threshold, the distance FFT processing unit 41 may determine that there is a predetermined object 200 at the distance corresponding to the peak. For example, a method is known in which when a peak value equal to or greater than a threshold is detected from the average power or amplitude of an external disturbance signal, as in a detection process using a constant false alarm rate (CFAR), it is determined that there is an object (reflecting object) that reflects the transmitted wave. The determination as to whether an object exists based on such a threshold may be executed, for example, in the threshold determination unit 45 described later.

[0063] As described above, the electronic device 1 according to one embodiment can detect an object 200 that reflects the transmitted wave T based on the transmitted signal transmitted as the transmitted wave T and the received signal received as the reflected wave R.

[0064] The distance FFT processing unit 41 can estimate the distance to a predetermined object based on one chirp signal (e.g., c1 shown in FIG. 5). That is, the electronic device 1 can measure (estimate) the distance A shown in FIG. 1 by performing distance FFT processing. Since the technique of measuring (estimating) the distance to a predetermined object by performing FFT processing on the beat signal is already known, a more detailed description will be appropriately simplified or omitted. The result of the distance FFT processing performed by the distance FFT processing unit 41 (e.g., distance information) may be supplied to the speed FFT processing unit 42. Also, the result of the distance FFT processing performed by the distance FFT processing unit 41 may be supplied to other functional units such as, for example, the threshold determination unit 45.

[0065] The speed FFT processing unit 42 estimates the relative speed between the moving body 100 on which the electronic device 1 is mounted and the object 200 based on the beat signal on which the distance FFT processing has been performed by the distance FFT processing unit 41. The speed FFT processing unit 42 may include, for example, a processing unit that performs fast Fourier transform. In this case, the speed FFT processing unit 42 may be configured by any circuit or chip that performs fast Fourier transform (FFT) processing.

[0066] The velocity FFT processing unit 42 further performs FFT processing on the beat signal on which the range FFT processing has been performed by the range FFT processing unit 41 (hereinafter, appropriately referred to as "velocity FFT processing"). The velocity FFT processing is also referred to as 2D FFT (Doppler FFT) processing. For example, the velocity FFT processing unit 42 may perform FFT processing on the complex signal supplied from the range FFT processing unit 41. The velocity FFT processing unit 42 can estimate the relative velocity with a predetermined object based on the sub-frame of the chirp signal (for example, sub-frame 1 shown in FIG. 5). When the range FFT processing is performed on the beat signal as described above, a plurality of vectors can be generated. By obtaining the phase of the peak in the result of performing the velocity FFT processing on these plurality of vectors, the relative velocity with a predetermined object can be estimated. That is, the electronic device 1 can measure (estimate) the relative velocity between the moving body 100 shown in FIG. 1 and the predetermined object 200 by performing the velocity FFT processing. Since the technique of measuring (estimating) the relative velocity with a predetermined object by performing the velocity FFT processing on the result of performing the range FFT processing is known per se, more detailed description will be appropriately simplified or omitted. The result (for example, velocity information) of the velocity FFT processing performed by the velocity FFT processing unit 42 may be supplied to the synthesizing unit 43. Further, the result (for example, velocity information) of the velocity FFT processing performed by the velocity FFT processing unit 42 may be supplied to, for example, the threshold determination unit 45. Further, the result of the velocity FFT processing performed by the velocity FFT processing unit 42 may be supplied to other functional units such as, for example, the arrival angle estimation unit 46.

[0067] The synthesizing unit 43 synthesizes the information based on the result of the velocity FFT processing performed by the velocity FFT processing unit 42 a predetermined number of times. The predetermined number of times that the information based on the result of the velocity FFT processing is synthesized by the synthesizing unit 43 may be read from the synthesis number storage unit 44. The synthesis processing by the synthesizing unit 43 will be further described later.

[0068] The composite number storage unit 44 may be a memory that stores the number of times (composite number) that the combining unit 43 performs the combining process. The composite number storage unit 44 can be configured by, for example, a semiconductor memory or a magnetic disk, etc., but is not limited thereto and can be any storage device. Also, for example, the composite number storage unit 44 may be a storage medium such as a memory card inserted into the electronic device 1 according to the present embodiment. Further, as described above, the composite number storage unit 44 may be an internal memory such as a CPU used as the control unit 10 and / or the signal processing unit 40.

[0069] In one embodiment, the composite number stored in the composite number storage unit 44 may be notified from the control unit 10. More specifically, the composite number stored in the composite number storage unit 44 may be notified, for example, from the mode selection unit 11 of the control unit 10. That is, the mode selection unit 11 of the control unit 10 may notify the composite number storage unit 44 of the signal processing unit 40 according to the selected mode. Thereby, the composite number storage unit 44 can store the notified composite number.

[0070] The threshold determination unit 45 performs determination processing on the distance and / or relative speed based on the result of the distance FFT processing performed by the distance FFT processing unit 41 and / or the result of the speed FFT processing performed by the speed FFT processing unit 42. In one embodiment, the threshold determination unit 45 may perform determination processing on the distance and / or relative speed based on the result of the speed FFT processing synthesized by the combining unit 43. In one embodiment, the threshold determination unit 45 may perform determination based on a predetermined threshold. For example, the threshold determination unit 45 may determine whether the result of the distance FFT processing performed by the distance FFT processing unit 41 and / or the result of the speed FFT processing performed by the speed FFT processing unit 42 exceeds a predetermined threshold. Also, the threshold determination unit 45 may determine, for example, whether the result of the speed FFT processing performed by the speed FFT processing unit 42 synthesized by the combining unit 43 exceeds a predetermined threshold. The threshold determination unit 45 may determine that an object has been detected at a distance and / or relative speed that exceeds a predetermined threshold.

[0071] The threshold determination unit 45 may output only those that exceed a predetermined threshold among the results of the distance FFT processing performed by the distance FFT processing unit 41 and / or the results of the velocity FFT processing performed by the velocity FFT processing unit 42. In one embodiment, the threshold determination unit 45 may output only those that exceed a predetermined threshold among those synthesized by the synthesis unit 43 from the results of the velocity FFT processing. The operation performed by the threshold determination unit 45 may be, for example, similar to the detection processing based on a constant false alarm rate (CFAR). In one embodiment, the operation performed by the threshold determination unit 45 may perform a process based on Order Statistic CFAR (OS-CFAR). OS-CFER is a method of setting a threshold based on ordered statistics and determining that a target exists when the threshold is exceeded. The result of the threshold determination process performed by the threshold determination unit 45 may be supplied to the arrival angle estimation unit 46. Further, the result of the process performed by the threshold determination unit 45 may be supplied to other functional units such as, for example, the object detection unit 47 and / or the output determination unit 48.

[0072] When the electronic device 1 operates in a plurality of operation modes (radar modes), the threshold determination unit 45 may determine the presence or absence of an object based on the CFAR (for example, OS-CFER) threshold stored for each radar mode.

[0073] The arrival angle estimation unit 46 estimates the direction from which the reflected wave R arrives from a predetermined object 200 based on the result of the velocity FFT processing performed by the velocity FFT processing unit 42 and / or the output from the threshold determination unit 45. The arrival angle estimation unit 46 may estimate the direction from which the reflected wave R arrives from a predetermined object 200 based on the result output from the threshold determination unit 45 among the results of the velocity FFT processing performed by the velocity FFT processing unit 42. The electronic device 1 can estimate the direction from which the reflected wave R arrives by receiving the reflected wave R from the plurality of receiving antennas 31. For example, it is assumed that the plurality of receiving antennas 31 are arranged at a predetermined interval. In this case, the transmitted wave T transmitted from the transmitting antenna 25 is reflected by a predetermined object 200 to become the reflected wave R, and the plurality of receiving antennas 31 arranged at a predetermined interval each receive the reflected wave R. Then, the arrival angle estimation unit 46 can estimate the direction from which the reflected wave R arrives at the receiving antenna 31 based on the phase of the reflected wave R received by each of the plurality of receiving antennas 31 and the path difference of each reflected wave R. That is, the electronic device 1 can measure (estimate) the arrival angle θ shown in FIG. 1 based on the result of the velocity FFT processing.

[0074] In the electronic device 1 according to an embodiment, the arrival angle estimation unit 46 may estimate the arrival direction of the reflected wave based on the complex signals received by the plurality of receiving antennas 31 at the velocity determined to have an object present. In this way, the electronic device 1 according to an embodiment can estimate the angle of the direction in which the object is present.

[0075] Based on the result of performing speed FFT processing, various techniques for estimating the direction in which the reflected wave R arrives have been proposed. For example, as known arrival direction estimation algorithms, MUSIC (MUltiple SIgnal Classification) and ESPRIT (Estimation of Signal Parameters via Rotational Invariance Technique) are known. Therefore, a more detailed explanation of the known techniques will be appropriately simplified or omitted as necessary. The information (angle information) of the arrival angle θ estimated by the arrival angle estimation unit 46 may be supplied to the object detection unit 47.

[0076] In the electronic device 1 according to one embodiment, the object detection unit 47 determines whether an object is detected (for example, clustered) as a target based on information on the arrival direction (angle) of the reflected wave, information on the relative speed with the target, and / or information on the distance to the target. Here, the information on the arrival direction (angle) of the reflected wave may be obtained from the arrival angle estimation unit 46. Also, the information on the relative speed and distance with the target may be obtained from the threshold determination unit 45. Further, the information on the relative speed with the target may be obtained from the speed FFT processing unit 42. Additionally, the information on the distance to the target may be obtained from the distance FFT processing unit 41. The object detection unit 47 may calculate the average power of the points constituting the object detected as the target.

[0077] The object detection unit 47 detects an object existing in the range where the transmission wave T is transmitted, based on information supplied from at least any one of the distance FFT processing unit 41, the velocity FFT processing unit 42, the threshold determination unit 45, and the arrival angle estimation unit 46. The object detection unit 47 may perform object detection, for example, by performing clustering processing based on the supplied distance information, velocity information, and angle information. As an algorithm used when clustering data, for example, DBSCAN (Density-based spatial clustering of applications with noise) is known. In the clustering processing, for example, the average power of the points constituting the detected object may be calculated. The distance information, velocity information, angle information, and power information of the object detected by the object detection unit 47 may be supplied to the output determination unit 48. Further, the output from the object detection unit 47 may be supplied to other functional units, such as, for example, the ECU 50. In this case, when the moving body 100 is an automobile, communication may be performed using a communication interface such as, for example, CAN (Controller Area Network).

[0078] The output determination unit 48 may perform processing for predicting the target position of the object in the next frame that has been subjected to clustering processing, for example. The output determination unit 48 may predict the position of the object that has been subjected to clustering processing in the next frame, for example, by using a Kalman filter. The output determination unit 48 may store the predicted position of the object in the next frame in, for example, an arbitrary storage unit or the like.

[0079] In one embodiment, the output determination unit 48 may store in an arbitrary storage unit or the like which operation mode the detected object was detected in based on the point cloud related to the detected object. For example, the output determination unit 48 may store in a memory or the like whether the detected object was detected in the first radar mode or the second radar mode. In this case, the output determination unit 48 may determine the priority order between the first radar mode and the second radar mode according to whether the relative speed estimated in the previous frame is constant. Hereinafter, as an example, it will be described that the speed resolution of the first radar mode is higher (finer) than that of the second radar mode. For example, when an object is detected in both the first radar mode and the second radar mode, since the speed resolution of the first radar mode 1 is finer, the output determination unit 48 may give priority to the first radar mode. On the other hand, when an object is detected in only one of the first radar mode and the second radar mode, the output determination unit 48 may select the radar mode in which the object was detected.

[0080] As the point cloud related to the detected object, the output determination unit 48 may use data that associates between frames, for example, based on the principle of object tracking. In object tracking, the frames may be associated based on the correlation between the information of the object predicted in the previous frame stored in the memory (such as distance, angle, speed, power, variance of the point cloud, identification information, etc.) and the information of the object observed in the current frame. The output determination unit 48

[0081] The output determination unit 48 may perform prediction of the next frame using, for example, a Kalman filter from the information of the object observed in the current frame associated as described above. In this case, the output determination unit 48 may store the information of the object obtained by the prediction in an arbitrary memory or the like. Then, the output determination unit 48 may output the information of the object predicted in the current frame, which was calculated in the previous frame, among the information stored in the memory.

[0082] The ECU 50 (see FIG. 2) included in the electronic device 1 according to one embodiment can control the operation of the entire mobile body 100, including, for example, the control of each functional unit constituting the mobile body 100. In order to provide control and processing capabilities for executing various functions, the ECU 50 may include at least one processor, such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The ECU 50 may be realized by a single processor, may be realized by several processors, or may be realized by individual processors respectively. The processor may be realized as a single integrated circuit. The integrated circuit is also referred to as an IC (Integrated Circuit). The processor may be realized as a plurality of communicably connected integrated circuits and discrete circuits. The processor may be realized based on various other known technologies. In one embodiment, the ECU 50 may be configured, for example, as a CPU and a program executed by the CPU. The ECU 50 may appropriately include a memory necessary for the operation of the ECU 50. Also, at least a part of the functions of the control unit 10 may be the functions of the ECU 50, or at least a part of the functions of the ECU 50 may be the functions of the control unit 10.

[0083] The electronic device 1 shown in FIG. 2 includes two transmission antennas 25 and four reception antennas 31. However, the electronic device 1 according to one embodiment may include an arbitrary number of transmission antennas 25 and an arbitrary number of reception antennas 31. For example, by including two transmission antennas 25 and four reception antennas 31, the electronic device 1 can be considered to include a virtual antenna array configured by eight virtual antennas. In this way, the electronic device 1 may receive the reflected waves R of the 16 sub-frames shown in FIG. 5 by using, for example, eight virtual antennas.

[0084] Next, the operation of the electronic device 1 according to one embodiment will be described.

[0085] As described above, the electronic device 1 according to one embodiment transmits a transmission wave from a transmission antenna and receives a reflected wave obtained by reflecting the transmission wave by an object from a reception antenna. Then, the electronic device 1 according to one embodiment can detect an object that reflects the transmission wave based on a transmission signal and / or a reception signal. The electronic device 1 according to one embodiment discriminates whether or not the object detected in this way is a predetermined target. Hereinafter, the algorithm of the process by the electronic device 1 according to one embodiment will be further described.

[0086] In the electronic device 1 according to one embodiment, the mode selection unit 11 of the control unit 10 selects an operation mode of the electronic device 1 and notifies the selected operation mode to the parameter setting unit 12 and the signal processing unit 40. The parameter setting unit 12 sets parameters of the operation mode selected by the mode selection unit 11 and notifies the set parameters to the transmission unit 20. Here, an arbitrary memory or the like in the parameter setting unit 12 may store a plurality of radar parameters. The control unit 10 can switch a plurality of radar modes within, for example, one frame of a transmission wave by setting the radar parameters by the parameter setting unit 12.

[0087] Hereinafter, as an example, as described above, the electronic device 1 will be described as being operable to switch between a first operation mode in which the radar has a relatively high (fine) velocity resolution and a second operation mode in which the radar has a relatively low (coarse) velocity resolution. The mode selection unit 11 of the control unit 10 may determine whether the operation mode of the electronic device 1 is the first operation mode or the second operation mode and notify the result to the parameter setting unit 12 and the signal processing unit 40. Thereby, the signal processing unit 40 can grasp the operation mode when processing the reception signal. Further, the parameter setting unit 12 can set various parameters when transmitting the transmission signal and notify the transmission unit 20. Here, the parameter setting unit 12 may set radar parameters corresponding to the first operation mode and the second operation mode, respectively. Such radar parameters may be stored in an arbitrary storage unit in advance or may be acquired.

[0088] In one embodiment, the parameter setting unit 12 may set the following radar parameters, for example, in the first operation mode and the second operation mode. [Table 1]

[0089] In Table 1 above, the range resolution may be the resolution obtained during range Fourier transform (1D FFT). Also, the relative velocity resolution may be the resolution obtained during velocity Fourier transform (2D FFT). Also, the number of chirp signals may be the number of chirp signals transmitted in one subframe. The chirp interval may be the interval of time for transmitting the transmitted wave in one chirp signal. The subframe interval may indicate the product of the number of chirps and the chirp interval. The maximum number of subframe syntheses may be determined based on the number of subframes within one frame.

[0090] FIG. 6 is a diagram showing a region of the result of performing velocity Fourier transform (2D FFT) on the received signal in the electronic device 1. As shown in FIG. 6, the result of processing the received signal by the velocity FFT processing unit 42 of the signal processing unit 40 shows the range region and the velocity region. As an example, in the result shown in FIG. 6, the horizontal direction indicates the range region. In FIG. 6, the right direction indicates the direction away from the electronic device 1. In FIG. 6, the left direction indicates the direction approaching the electronic device 1. Also, in FIG. 6, the upward direction indicates the direction (positive direction) in which the relative velocity with the electronic device 1 increases. In FIG. 6, the downward direction indicates the direction (negative direction) in which the relative velocity with the electronic device 1 increases. Further, in FIG. 6, the central portion in the vertical direction indicates that the relative velocity with the electronic device 1 is small.

[0091] For example, as shown by arrows (1) and (2) in FIG. 6, when the relative speed of the detected object is high, in the result of the processing by the velocity FFT processing unit 42, as shown in FIG. 6, it is assumed that the object moves to adjacent cells (bins). In such a case, the received signal will be detected in two cells, and when the received signals are combined and averaged, the effect of averaging the signal-to-noise ratio (SNR) is not improved. In this case, when the received signals are combined, the effect of averaging becomes weaker. On the other hand, as shown by arrow (3) in FIG. 6, when the relative speed of the detected object is low, in the result of the processing by the velocity FFT processing unit 42, as shown in FIG. 6, it is assumed that the object does not move to adjacent cells. In such a case, when the received signals are combined and averaged, the noise is suppressed by the effect of averaging the SNR, and an improvement in the SNR can be expected. That is, in such a case, it can be expected that the accuracy of object detection is improved by combining the signals.

[0092] Next, the combining unit 43 of the signal processing unit 40 may combine the distance and relative speed between the electronic device 1 and the detected object according to the number of combinations set as the number of times of combining the received signals for the two-dimensional data as shown in FIG. 6. In this case, the combining unit 43 may calculate the above-mentioned number of combinations according to, for example, numerically values tabulated in advance. For example, in the case of the first operation mode, the velocity FFT processing unit 42 may perform 2D FFT on 256 chirp signals. Therefore, the velocity resolution of the 2D FFT in this case is, for example, accurate to 1 km / h.

[0093] Here, the setting of the number of combinations of the combining unit 43 will be further described. In the present disclosure, the combining unit 43 may set the number of combinations N by, for example, a combination number formula as shown in the following formula (1). [Frame interval or sub-frame interval of the transmission wave] × [m × distance resolution] / ([Velocity resolution] × [corresponding velocity bin]) (1) In the above formula (1), m may be a number of 0.5 or less. If m is less than or equal to half of the frame interval or sub-frame interval of the transmission wave, the movement to other bins can be restricted. Further, when calculating the synthesis number, the synthesis unit 43 may use other mathematical formulas in addition to the above formula (1).

[0094] The synthesis number in the present disclosure may be an integer. Further, when the result of the above calculation is not an integer, the synthesis unit 43 may round down or round up the decimal part. Also, the velocity resolution × the corresponding velocity bin may be described as the defined velocity. In the above formula (1), the denominator is set to [velocity resolution] × [corresponding velocity bin]. Here, the corresponding velocity bin is a positive integer 1,..., M, and M is (maximum measurement velocity / velocity resolution).

[0095] Further, in the above formula (1), the denominator may be set to [velocity resolution] × [velocity index (1,..., M)]. That is, in the present disclosure, the synthesis unit 43 may set the synthesis number N by a synthesis number formula as shown in, for example, the following formula (2). [Frame interval or sub-frame interval of the transmission wave] × [m × [range resolution] / ([velocity resolution] × [velocity index]) (2) In the above formula (2), the velocity index is a positive integer, and M is (maximum measurement velocity / velocity resolution).

[0096] The velocity FFT process performed in the velocity FFT processing unit 42 may be performed according to a mathematical formula such as the following formula (3), for example.

Number

[0097] In the case of FFT processing in the speed domain, in the exp in the above formula (3), N is the number of chirp signals. In the above formula (3), x makes a full circle of 360° from 0 to N - 1. Therefore, the largest gain can be obtained when the speed of the detected object is constant. For example, in the case of the operation in the second operation mode, 64 chirp signals may be transmitted 4 times. Thereby, the received signals can be synthesized. For example, when the synthesizing unit 43 synthesizes the received signals 3 times (that is, when synthesizing 4 sub-frames), the SNR can be improved by suppressing noise.

[0098] FIG. 7 is a diagram showing the detection result by 2D FFT before the received signal is synthesized by the synthesizing unit 43, that is, before the effect of averaging appears. FIG. 8 is a diagram showing the detection result by 2D FFT after the received signal is synthesized by the synthesizing unit 43, that is, after the effect of averaging appears. As shown in FIG. 8, it can be confirmed that the component of the noise floor is reduced compared with the result of FIG. 7. That is, as shown in FIG. 8, according to the electronic device 1 according to one embodiment, the SNR can be improved.

[0099] In the above-described embodiments, it has been described that the distance resolutions are the same in the first operation mode and the second operation mode. However, the distance resolutions may be different in the first operation mode and the second operation mode, respectively. Also, in the above-described embodiments, the electronic device 1 has been configured to operate by switching between the two operation modes of the first operation mode and the second operation mode. However, in one embodiment, the electronic device 1 may operate in, for example, three or more operation modes.

[0100] The electronic device 1 according to an embodiment may operate in a plurality of radar modes where, for example, the distance resolution is the same or substantially the same, and the relative speed resolution is different. The electronic device 1 according to an embodiment may switch the radar mode within one frame of the transmission wave. Further, the plurality of radar modes may be, for example, a first operation mode with a high relative speed resolution and a second operation mode that synthesizes received signals according to the relative speed resolution and / or the distance resolution. Further, in the second operation mode, an operation mode averaged so that the detected object does not span the distance domain of the result in the velocity FFT processing may be used. Thus, according to the electronic device 1 according to an embodiment, CFAR and / or estimation of the direction of arrival can be performed using a signal with improved SNR.

[0101] As described above, in the electronic device 1 according to an embodiment, the signal processing unit 40 may calculate the distance and relative speed between the object that reflects the transmission wave and the own device based on the transmission signal transmitted as the transmission wave and the reception signal received as the reflected wave. Further, the signal processing unit 40 may synthesize the distance and relative speed between the object that reflects the transmission wave and the own device according to the number of syntheses set as the number of times of synthesizing the reception signals. That is, according to the electronic device 1 according to an embodiment, noise can be suppressed before the object moves to adjacent cells in the result of the processing by the velocity FFT processing unit 42.

[0102] Further, in the electronic device 1 according to an embodiment, the control unit 10 may set the number of times of synthesizing the distance and relative speed between the object that reflects the transmission wave and the own device based on a predetermined condition. Here, the predetermined condition may be, for example, at least any one of the distance resolution between the object that reflects the transmission wave and the own device, the relative speed resolution between the object that reflects the transmission wave and the own device, and the frame interval or sub-frame interval of the transmission wave.

[0103] Further, in the electronic device 1 according to one embodiment, the control unit 10 may control to operate in a first operation mode and a second operation mode in which the transmission modes of the transmission waves are different. Here, the first operation mode may be a mode in which the resolution of the relative speed between the object that reflects the transmission wave and the own device is equal to or higher than a predetermined value. Also, the second operation mode may be a mode in which the resolution of the relative speed between the object that reflects the transmission wave and the own device is lower than the predetermined value.

[0104] Further, in the electronic device 1 according to one embodiment, when an object is detected in both the first operation mode and the second operation mode and the relative speed between the object and the own device is equal to or higher than a predetermined value, the control unit 10 may control to operate in the first operation mode. That is, in the electronic device 1 according to one embodiment, when the number of combined received signals in the first operation mode and the second operation mode is the same, the control unit 10 may control to operate in the first operation mode.

[0105] Further, in the electronic device 1 according to one embodiment, when the relative speed between the detected object and the own device is equal to or lower than a predetermined value, the control unit 10 may control to operate in the second operation mode. That is, in the electronic device 1 according to one embodiment, when the number of combined received signals in the second operation mode is larger, the control unit 10 may control to operate in the second operation mode.

[0106] Further, in the electronic device 1 according to one embodiment, when an object is detected in either the first operation mode or the second operation mode, the control unit 10 may control to operate in the mode in which the object is detected.

[0107] Further, in the electronic device 1 according to one embodiment, the signal processing unit 40 may calculate the moving distance of the object based on the relative speed between the detected object and the own device and the time between frames of the transmission wave. Also, the signal processing unit 40 may determine whether to combine the distance and the relative speed between the detected object and the own device according to whether the moving distance of the object moves to adjacent cells in the distance region of the result of the velocity Fourier transform process.

[0108] Also, in the electronic device 1 according to an embodiment, before the threshold determination process with a constant false alarm probability, the signal processing unit 40 may synthesize the distance and relative speed between the detected object and the own device according to the set number of syntheses.

[0109] Also, in the electronic device 1 according to an embodiment, the control unit 10 may switch between the first operation mode and the second operation mode within one frame of the transmission wave. The first operation mode and the second operation mode may be modes in which the resolution of the relative speed is different depending on the number of chirp signals included in the frame of the transmission wave.

[0110] In object detection by radar technology, for example, when the relative speed between the own device and the object is small, a process of performing frame synthesis processing to accurately measure the position of the object and, if the relative speed is large, performing angle synthesis processing to accurately measure the distance to the object is also assumed. However, the criterion for determining whether the relative speed between the own device and the object is low or high is only known after the object is detected. Therefore, in a state where the received signals cannot be synthesized, the SNR is low, so there is also a risk of non-detection or a risk of failure in the synthesis determination and inability to measure accurately.

[0111] Also, for example, when the relative speed of an object that reflects the transmission wave increases, a process of measuring the distance of the reflector in response to the change is also assumed. However, when the relative speed between the own device and the object is low, the SNR by frame synthesis is high, so the object can be detected. On the other hand, when the previous determination changes due to a change in the relative speed, it is also assumed that non-detection may occur due to a change in the SNR.

[0112] According to the electronic device 1 according to an embodiment, when detecting an object, for an object having a constant relative speed with respect to the own device, the resolution of the relative speed may be increased. Further, according to the electronic device 1 according to an embodiment, when detecting an object, for an object having a relative speed with respect to the own device that is equal to or less than a predetermined magnitude, the resolution of the relative speed may be increased. Thereby, since the signal level can be improved, the SNR is improved and the detection rate of the object can be improved. Further, according to the electronic device 1 according to an embodiment, for a detected object having a large relative speed with respect to the own device, that is, a relative speed greater than a predetermined magnitude, the resolution of the relative speed may be made low (coarse). By doing so, the electronic device 1 according to an embodiment can synthesize received signals within a range that does not exceed the regions of the distance resolution and the relative speed resolution. For this reason, according to the electronic device 1 according to an embodiment, the noise level can be suppressed and the detection rate of the object can be improved. Furthermore, according to the electronic device 1 according to an embodiment, by operating while switching between a plurality of operation modes as described above in one frame, the robustness of the detection process can be enhanced.

[0113] Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications or corrections based on the present disclosure. Therefore, it should be noted that these modifications or corrections are included in the scope of the present disclosure. For example, the functions included in each functional unit can be rearranged so as not to be logically contradictory. A plurality of functional units, etc. may be combined into one or divided. Each of the embodiments according to the present disclosure described above is not limited to being faithfully implemented in each of the described embodiments, and can be implemented by appropriately combining each feature or omitting a part. That is, those skilled in the art can make various modifications and corrections based on the present disclosure for the content of the present disclosure. Therefore, these modifications and corrections are included in the scope of the present disclosure. For example, in each embodiment, each functional unit, each means, each step, etc. can be added to other embodiments so as not to be logically contradictory, or replaced with each functional unit, each means, each step, etc. of other embodiments. Also, in each embodiment, a plurality of each functional unit, each means, each step, etc. can be combined into one or divided. Also, each of the embodiments of the present disclosure described above is not limited to being faithfully implemented in each of the described embodiments, and can also be implemented by appropriately combining each feature or omitting a part.

[0114] For example, in the above-described embodiment, the mode of dynamically switching the object detection range by one sensor 5 has been described. However, in one embodiment, object detection may be performed within the determined object detection range by a plurality of sensors 5. Also, in one embodiment, beamforming may be performed toward the determined object detection range by a plurality of sensors 5.

[0115] The above-described embodiments are not limited to being implemented only as the electronic device 1. For example, the above-described embodiments may be implemented as a control method for a device such as the electronic device 1. Further, for example, the above-described embodiments may be implemented as a program to be executed on a device such as the electronic device 1 or a computer.

[0116] The electronic device 1 according to one embodiment may include at least a part of only one of, for example, the sensor 5 or the control unit 10 as the minimum configuration. On the other hand, the electronic device 1 according to one embodiment may be configured to appropriately include at least any one of a signal generation unit 21, a synthesizer 22, a phase control unit 23, an amplifier 24, and a transmission antenna 25 as shown in FIG. 2 in addition to the control unit 10. Further, the electronic device 1 according to one embodiment may be configured to appropriately include at least any one of a reception antenna 31, an LNA 32, a mixer 33, an IF unit 34, and an AD conversion unit 35 instead of or together with the above-described functional units. Furthermore, the electronic device 1 according to one embodiment may be configured to include an arbitrary storage unit (memory). Thus, the electronic device 1 according to one embodiment can adopt various configuration modes. When the electronic device 1 according to one embodiment is mounted on the moving body 100, for example, at least any one of the above-described functional units may be installed at an appropriate location inside the moving body 100 or the like. On the other hand, in one embodiment, for example, at least any one of the transmission antenna 25 and the reception antenna 31 may be installed outside the moving body 100.

Explanation of Reference Numerals

[0117] 1 Electronic device 5 Sensor 10 Control unit 11 Mode selection unit 12 Parameter setting unit 20 Transmission unit 21 Signal generation unit 22 Synthesizer 23 Phase control unit 24 Amplifier 25 Transmission antenna 30 Reception unit 31 Reception antenna 32 LNA 33 Mixer 34 IF unit 35 AD conversion unit 40 Signal processing unit 41 Distance FFT processing unit 42 Velocity FFT processing unit 43 Synthesis unit 44 Composite number memory unit 45 Threshold determination unit 46 Arrival angle estimation unit 47 Object detection unit 48 Output determination unit 50 ECU 100 Moving body 200 Object

Claims

1. A transmitting antenna that transmits a transmission wave, A receiving antenna that receives a reflected wave obtained by reflecting the transmission wave, A signal processing unit that calculates the distance and relative speed between an object that reflects the transmission wave and the own device based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave, Comprising: The signal processing unit synthesizes the distance and the relative speed according to the number of syntheses set as the number of times of synthesizing the reception signal, The number of syntheses is a number that increases as the distance resolution in the signal processing unit increases and decreases as the speed resolution in the signal processing unit increases, an electronic device.

2. The electronic device according to claim 1, further comprising a control unit that sets the number of syntheses based on at least any one of the resolution of the distance, the resolution of the relative speed, and the frame interval or sub-frame interval of the transmission wave.

3. The control unit controls to operate in a first operation mode and a second operation mode in which the transmission modes of the transmission wave are different, The first operation mode is a mode in which the resolution of the relative speed operates at a predetermined value or more, The second operation mode is a mode that operates when the resolution of the relative speed is less than the predetermined value, the electronic device according to claim 2.

4. The control unit controls to operate in the first operation mode when the object is detected in both the first operation mode and the second operation mode and the relative speed between the object and the own device is a predetermined value or more, the electronic device according to claim 3.

5. The control unit controls to operate in the second operation mode when the relative speed between the object and the own device is a predetermined value or less, the electronic device according to claim 3 or 4.

6. The control unit controls to operate in the mode at the time when the object is detected when the object is detected in either the first operation mode or the second operation mode, the electronic device according to any one of claims 3 to 5.

7. The signal processing unit calculates the moving distance of the object based on the relative speed between the object and the own device and the time between frames of the transmission wave, and whether or not the distance and the relative speed are synthesized according to whether or not the moving distance moves to adjacent cells in the distance region of the result of the velocity Fourier transform process, the electronic device according to claim 1.

8. The signal processing unit, Before the threshold determination process with a certain false alarm probability, the distance and the relative speed are synthesized according to the synthesized number, the electronic device according to any one of claims 1 to 7.

9. The control unit switches between the first operation mode and the second operation mode within one frame of the transmission wave, the electronic device according to any one of claims 3 to 6.

10. The first operation mode and the second operation mode are modes in which the resolution of the relative speed differs depending on the number of chirp signals included in the frame of the transmission wave, the electronic device according to any one of claims 3 to 9.

11. A step of transmitting a transmission wave; A step of receiving a reflected wave reflected by the transmission wave; Based on the transmission signal transmitted as the transmission wave and the reception signal received as the reflected wave, a step of calculating the distance and the relative speed between the object reflecting the transmission wave and the own device; A step of synthesizing the distance and the relative speed according to the synthesized number set as the number of times of synthesizing the reception signals; including The synthesized number is a number that becomes larger as the distance resolution in the calculating step becomes larger and becomes smaller as the speed resolution in the calculating step becomes larger, a control method for an electronic device.

12. In an electronic device, A step of transmitting a transmission wave; A step of receiving a reflected wave reflected by the transmission wave; Based on the transmission signal transmitted as the transmission wave and the reception signal received as the reflected wave, a step of calculating the distance and the relative speed between the object reflecting the transmission wave and the own device; A step of synthesizing the distance and the relative speed according to the synthesized number set as the number of times of synthesizing the reception signals; causing to execute The synthesized number is a number that becomes larger as the distance resolution in the calculating step becomes larger and becomes smaller as the speed resolution in the calculating step becomes larger, a program.

13. The synthesized number is such that m is a number less than or equal to a predetermined value, the corresponding speed bin is a positive integer, and the speed index is a positive integer, [Frame interval or sub-frame interval of the transmission wave] × [m × distance resolution] / ([speed resolution] × [corresponding speed bin]), or Calculated by [frame interval or sub-frame interval of the transmission wave] × [m × [distance resolution] / ([speed resolution] × [speed index])], the electronic device according to claim 1.

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