Patent Description:
The present disclosure relates to an electronic device, a method for controlling electronic device, and an electronic device control program.

For example, in the field of industries related to automobiles, a technique for measuring distance between an own vehicle and an object is important. In particular, in recent years, RADAR (Radio Detecting and Ranging) technique for measuring distance between the own vehicle and the object by transmitting radio waves such as millimeter waves and receiving reflected waves obtained by reflection by the object such as an obstacle has been studied in various ways. The importance of technique for measuring such distances and the like is expected to grow more and more in the future with development of techniques that assist drivers in driving and related to automated driving that automates a part or all of driving.

Further, various techniques for detecting presence of an object by receiving reflected waves obtained by reflection of the transmitted radio waves by a predetermined object, have also been proposed. For example, PLT <NUM> discloses a technique for improving the safety of a vehicle by making it difficult for the safety system to operate even if an obstacle candidate is erroneously detected. Further, for example, PLT <NUM> discloses a technique for facilitating detection by radar even for a weakly reflecting object such as a pedestrian. Further, for example, PLT <NUM> discloses a technique for suppressing inconvenience caused by a millimeter wave radar detecting an object that is not an obstacle. Similar systems are also disclosed in <CIT>, <CIT> and <CIT>.

According to the present invention, an electronic device according to claim <NUM>, a method for controlling an electronic device according to claim <NUM>, and an electronic device control program according to claim <NUM> are provided.

It is desirable to improve accuracy of detection in a technique for detecting presence of the predetermined object by receiving reflected waves obtained by reflection of the transmitted waves by a predetermined object (object). An objective of the present disclosure is to provide an electronic device, a method for controlling an electronic device, and an electronic device control program that can improve accuracy of detecting an object having reflected the transmitted waves. According to an embodiment, an electronic device, a method for controlling electronic device, and an electronic device control program that can improve accuracy of detecting an object having reflected transmitted waves can be provided. Hereinafter, an embodiment will be described in detail with reference to the drawings.

An electronic device according to an embodiment, for example, by being mounted on a vehicle such as an automobile (mobile body), can detect a predetermined object existing around the mobile body. For this reason, an electronic device according to an embodiment can transmit transmitted waves from a transmitting antenna installed on a mobile body to surroundings of the mobile body. Further, an electronic device according to an embodiment can receive reflected waves obtained by reflection of the transmitted waves from a receiving antenna installed on the mobile body. At least one of the transmitting antenna and the receiving antenna may be provided, for example, in a radar sensor or the like installed in the mobile body.

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 as an example of a mobile body will be described. However, mobile bodies on which an electronic device according to an embodiment is mounted is not limited to the automobile. An electronic device according to an embodiment may be mounted on a variety of mobile bodies, such as buses, trucks, motorcycles, bicycles, ships, aircrafts agricultural vehicles such as tractors, fire engines, ambulances, police vehicles, snowplows, cleaning vehicles for cleaning roads, drones, or the like, or on pedestrians. In addition, the electronic devices according to an embodiment are not necessarily limited to be mounted on a mobile body that moves under its own power. For example, a mobile body on which an electronic device according to an embodiment is mounted may be a trailer part towed by a tractor.

Firstly, an example of detecting an object by an electronic device according to an embodiment will be described.

<FIG> is a diagram for explaining usage of an electronic device according to an embodiment. <FIG> shows an example in which a sensor comprising a transmitting antenna and a receiving antenna according to an embodiment is installed on a mobile body.

In a mobile body <NUM> shown in <FIG>, a sensor <NUM> comprising a transmitting antenna and a receiving antenna according to an embodiment is installed. Further, the mobile body <NUM> shown in <FIG> shall be equipped with an electronic device <NUM> according to an embodiment (for example, built-in). A specific configuration of the electronic device <NUM> will be described below. The sensor <NUM> may comprise, for example, at least one of a transmitting antenna and a receiving antenna. Further, the sensor <NUM> may also include at least one of other functional parts such as at least a part of a controller <NUM> included in the electronic device <NUM> (<FIG> or <FIG>), as appropriate. The mobile body <NUM> shown in <FIG> may be an automobile vehicle, such as a passenger car, but may be an arbitrary type of mobile body. In <FIG> , the mobile body <NUM>, for example, may be moving (traveling or slow traveling) in the Y-axis positive direction (traveling direction) shown in <FIG>, or may be moving in other directions, or may be stationary without moving.

As shown in <FIG>, the sensor <NUM> comprising a plurality of transmitting antennas is installed on a mobile body <NUM>. In the example shown in <FIG>, only one sensor <NUM> comprising the transmitting antenna and the receiving antenna is installed in front of the mobile body <NUM>. Here, a position where the sensor <NUM> is installed in the mobile body <NUM> is not limited to the position shown in <FIG>, but may be other positions as appropriate. For example, the sensor <NUM> as shown in <FIG> may be installed on the left, right, and / or rear of the mobile body <NUM>. Further, a number of such sensors <NUM> may be an arbitrary number of one or more, depending on various conditions (or requirements) such as a range and / or accuracy of the measurement in the mobile body <NUM>.

The sensor <NUM> transmits electromagnetic waves as transmitted waves from a transmitting antenna. For example, if there is a predetermined object (for example, object <NUM> shown in <FIG>) around the mobile body <NUM>, at least a part of transmitted waves transmitted from the sensor <NUM> is reflected by the object and becomes reflected waves. Then, by receiving such reflected waves by the receiving antenna of the sensor <NUM> for example, the electronic device <NUM> mounted on the mobile body <NUM> can detect the object.

The sensor <NUM> comprising a transmitting antenna may typically be a radar (RADAR(Radio Detecting and Ranging) sensor that transmits and receives radio waves. However, the sensor <NUM> is not limited to the radar sensor. The sensor <NUM> according to an embodiment may be a sensor based on a technique of, for example, LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) by light waves. Further, the sensor <NUM> according to an embodiment may be a sensor based on the technique of, for example, SONAR (Sound Navigation and Ranging) by sound waves. Such sensors can be configured to include, for example, a patch antenna. Because techniques such as RADAR, LIDAR and SONAR have been already known, detailed descriptions may be simplified or omitted as appropriate.

The electronic device <NUM> mounted on the mobile body <NUM> shown in <FIG> receives reflected waves obtained by reflection of the transmitted waves transmitted from a transmitting antenna of the sensor <NUM>, from the receiving antenna. In this way, the electronic device <NUM> can detect a predetermined object <NUM> existing within a predetermined distance from the mobile body <NUM>. For example, as shown in <FIG>, the electronic device <NUM> can measure a distance L between the mobile body <NUM>, which is its own vehicle, and the predetermined object <NUM>. Further, the electronic device <NUM> can also measure relative speed between the mobile body <NUM>, which is its own vehicle, and the predetermined object <NUM>. Furthermore, the electronic device <NUM> can also measure an arrival direction (arrival angle θ) in which reflected waves from the predetermined object <NUM> arrives at the mobile body <NUM>, which is its own vehicle.

Here, the object <NUM> may be at least one of, for example, an oncoming vehicle traveling in a lane adjacent to the mobile body <NUM>, a vehicle traveling in parallel with the mobile body <NUM>, and a vehicle in front of or behind the mobile body <NUM> traveling in the same lane as the mobile body <NUM>. Further, the object <NUM> may be an arbitrary body existing around the mobile body <NUM>, such as motorcycles, bicycles, strollers, pedestrians, guardrails, medians, road signs, sidewalk steps, walls, obstacles, manholes and the like. Furthermore, the object <NUM> may be moving or stationary. For example, the object <NUM> may be an automobile parked or stopped around the mobile body <NUM>. In the present disclosure, objects detected by the sensor <NUM> include inanimate objects as well as organisms such as humans or animals.

In <FIG>, a ratio of the size of the sensor <NUM> to the size of the mobile body <NUM> does not necessarily represent an actual ratio. Further, in <FIG>, the sensor <NUM> shows a state of being installed outside the mobile body <NUM>. However, in an embodiment, the sensor <NUM> may be installed in various positions on the mobile body <NUM>. For example, in an embodiment, the sensor <NUM> may be installed inside the bumper of the mobile body <NUM> so that it does not appear on the exterior of the mobile body <NUM>. The position where the sensor <NUM> is installed on the mobile body <NUM> may be either outside or inside the mobile body <NUM>. The inside the mobile body <NUM> may be, for example, the inside a body of the mobile body <NUM>, the inside of bumpers, the inside of headlights, the inside of space of the vehicle or any combination of these.

Hereinafter, as a typical example, the transmitting antenna of the sensor <NUM> will be described as transmitting radio waves in a frequency band such as millimeter wave (above <NUM>) or quasi-millimeter wave (for example, around <NUM> to <NUM>). For example, the transmitting antenna of the sensor <NUM> may transmit radio waves with a frequency bandwidth of <NUM>, such as <NUM> to <NUM>.

<FIG> is a functional block diagram for schematically showing an example of a configuration of the electronic device <NUM> according to an embodiment. Hereinafter, an example of a configuration of the electronic device <NUM> according to an embodiment will be described.

When measuring distance or the like by a millimeter wave radar, a frequency modulated continuous wave radar (hereafter referred to as FMCW radar (Frequency Modulated Continuous Wave radar)) is often used. The FMCW radar sweeps frequencies of radio waves to be transmitted, and thereby transmitted signals are generated. Therefore, for example, in a millimeter wave FMCW radar that uses radio waves in the <NUM> frequency band, the frequency of the radio waves used will have a frequency bandwidth of <NUM>, for example, such as <NUM> to <NUM>. A radar in the <NUM> frequency band is characterized by a wider usable frequency bandwidth than other millimeter wave / quasi-millimeter wave radars, such as those in the <NUM>, <NUM>, and <NUM> frequency bands. Hereinafter, such an embodiment will be described. Further, the FMCW radar method used in the present disclosure may include the FCM (Fast-Chirp Modulation) method, which transmits chirp signals with a shorter cycle than usual. The signals generated by a signal generator <NUM> are not limited to signals of the FMCW method. The signals generated by the signal generator <NUM> may be signals of various methods other than the FMCW method. The transmitted signal sequence stored in a storage may be different for these various methods. For example, in the case of radar signals of the FMCW method described above, signals whose frequency increases and decreases with each time sample may be used. Because known techniques can be appropriately applied to the various methods described above, more detailed description thereof will be omitted.

As shown in <FIG>, an electronic device <NUM> according to an embodiment comprises the sensor <NUM> and the controller <NUM>. Further, the sensor <NUM> may include a transmitter <NUM> and receivers 30A to 30D. As shown in <FIG>, the electronic device <NUM> may comprise a plurality of receivers, such as the receivers 30A to 30D. Hereinafter, when the receiver 30A, the receiver 30B, the receiver 30C, and the receiver 30D are not distinguished, they are simply referred to as "receiver <NUM>".

In an example shown in <FIG>, the sensor <NUM> and the controller <NUM> are shown as different functional parts, but the sensor <NUM> may include all or a part of the controller <NUM>. Further, the member included in the sensor <NUM> is not limited to the example shown in <FIG>, and any member among the members shown in <FIG> may be removed from the sensor <NUM>. In <FIG>, for example, the transmitting antenna <NUM>, the receiving antenna <NUM> and the amplifier <NUM> may be housed in a single enclosure as the sensor <NUM>. Further, for example, the sensor <NUM> may include at least one of the transmitting antenna <NUM> and the receiving antenna <NUM>.

The controller <NUM> shown in <FIG> may comprise a distance FFT processor <NUM>, a speed FFT processor <NUM>, an arrival angle estimator <NUM>, a determination processor <NUM>, a storage <NUM>, a clustering processor <NUM>, a tracking processor <NUM>, and an update processor <NUM>, as shown in more detail in <FIG>. These functional parts included in the controller <NUM> will be further described below.

As shown in <FIG>, the transmitter <NUM> may comprise a signal generator <NUM>, a synthesizer <NUM>, phase controllers 23A and 23B, amplifiers 24A and 24B, and transmitting antennas 25A and 25B. Hereinafter, when the transmitting antenna 25A and the transmitting antenna 25B are not distinguished, they are simply referred to as "transmitting antenna <NUM>". Also, as for other functional parts in the transmitter <NUM>, when a plurality of functional parts of the same type, such as the phase controller 23A and 23B, are not specifically distinguished, these functional parts may be collectively referred to by omitting symbols such as A and B.

As shown in <FIG>, the receiver <NUM> may comprise receiving antennas 31A to 31D corresponding to each of the plurality of receivers <NUM>. Hereinafter, when the receiving antenna 31A, the receiving antenna 31B, the receiving antenna 31C and the receiving antenna 31D are not distinguished, they are simply referred to as "receiving antenna <NUM>". Further, as shown in <FIG>, a plurality of receivers <NUM> may respectively comprise a LNA <NUM>, a mixer <NUM>, an IF part <NUM>, and an AD converter <NUM>. The receivers 30A to 30D may have the same configuration, respectively. In <FIG>, as a representative example, a configuration of only the receiver 30A is schematically shown.

As shown in <FIG>, the sensor <NUM> may comprise, for example, the transmitting antenna <NUM> and the receiving antenna <NUM>. Further, as described above, the sensor <NUM> may also include at least any one of the other functional parts, such as the controller <NUM> or at least a part of the controller <NUM>, as appropriate.

The controller10 comprised by the electronic device <NUM> according to an embodiment can control an operation of the entire electronic device <NUM> including control of each functional part constituting the electronic device <NUM>. The controller <NUM> may include at least one processor, such as a CPU (central processing unit), for example, in order to provide control and processing power for performing various functions. The controller <NUM> may be realized collectively by one processor, by several processors, or by individual processors. The processor may be realized as a single integrated circuit. An integrated circuit is also referred to as an IC (Integrated Circuit). A processor may be realized as a plurality of communicably connected integrated circuits and discrete circuits. A processor may be realized based on various other known techniques. In an embodiment, the controller <NUM> may be configured, for example, as a CPU and a program executed by the CPU. The controller <NUM> may appropriately include a memory necessary for an operation of the controller <NUM>.

As shown in <FIG>, the controller <NUM> comprises the storage <NUM>. The storage <NUM> may store programs executed by the controller <NUM>, results of process executed by the controller <NUM> and the like. Further, the storage <NUM> may function as a work memory for the controller <NUM>. The storage <NUM> can be configured by, for example, a semiconductor memory, a magnetic disk or the like, but is not limited to these, and can be an arbitrary storage device. Further, for example, the storage <NUM> may be a storage medium such as a memory card that is inserted in the electronic device <NUM> according to the present embodiment. Further, the storage <NUM> may also be an internal memory of a CPU that is used as the controller <NUM>, as described above.

In the electronic device <NUM> according to an embodiment, the controller <NUM> can control at least one of the transmitter <NUM> and the receiver <NUM>. In this case, the controller <NUM> may control at least one of the transmitter <NUM> and the receiver <NUM> based on various information stored in the storage <NUM>. Further, in the electronic device <NUM> according to an embodiment, the controller <NUM> may instruct the signal generator <NUM> to generate signals, or may control the signal generator <NUM> to generate signals.

The signal generator <NUM>, shown in <FIG>, generates the signals (transmitted signals) to be transmitted as transmitted waves T from the transmitting antenna <NUM> under the control of the controller <NUM>. The signal generator <NUM> may assign frequencies of transmitted signals, for example based on control by the controller <NUM> when generating transmitted signals. For example, the signal generator <NUM> generates signals with predetermined frequencies in a frequency band, such as <NUM> to <NUM>, by receiving frequency information from the controller <NUM>. The signal generator <NUM> may be configured to include a functional part such as a voltage controlled oscillator (VCO).

The signal generator <NUM> may be configured as a hardware including the function, for example, may be configured by a microcontroller and the like, or for example, may be configured as a combination of a processor such as a CPU and a program executed by the processor. Each functional part described below may also be configured as a hardware including the function, or if possible, for example, by a microcontroller and the like, or for example, as a combination of a processor such as a CPU and a program executed by the processor.

In the electronic device <NUM> according to an embodiment, the signal generator <NUM> may generate a transmitted signal (transmitted chirp signal) such as a chirp signal. In particular, the signal generator <NUM> may generate a signal (linear chirp signal) in which a frequency changes periodically and linearly. For example, the signal generator <NUM> may generate a chirp signal in which a frequency increases periodically and linearly from <NUM> to <NUM> with passage of time. Further, for example, the signal generator <NUM> may generate a signal in which a frequency periodically repeats linear increase (up chirp) and decrease (down chirp) from <NUM> to <NUM> with passage of time. The signal generated by the signal generator <NUM> may be preset in the controller <NUM>, for example. Further, the signal generated by the signal generator <NUM> may be stored in advance in a storage <NUM> or the like, for example. Because chirp signals used in technical fields such as radar are known, more detailed description will be simplified or omitted as appropriate. The signal generated by the signal generator <NUM> is supplied to the synthesizer <NUM>.

<FIG> is a diagram for explaining an example of a chirp signal generated by the signal generator <NUM>.

In <FIG>, the horizontal axis represents the passage of time, and the vertical axis represents the frequency. In the example shown in <FIG>, the signal generator <NUM> generates a linear chirp signal in which a frequency changes periodically and linearly. In <FIG>, each chirp signal is shown as c1, c2,. As shown in <FIG>, in each chirp signal, a frequency increases linearly with passage of time.

In an example shown in <FIG>, eight chirp signals such as c1, c2,. , C8 are included to form one subframe. That is, the subframe <NUM> and the subframe <NUM> shown in <FIG> are configured to include eight chirp signals such as c1, c2,. , C8, respectively. Further, in an example shown in <FIG>, <NUM> subframes such as subframes <NUM> to <NUM> are included to form one frame. That is, one frame consists of <NUM> subframes respectively, such as frame <NUM> and frame <NUM> shown in <FIG>. Further, as shown in <FIG>, frame intervals of a predetermined length may be included between frames.

In <FIG>, frame <NUM> and beyond may have a similar configuration. Further, in <FIG>, frame <NUM> and beyond may have a similar configuration. In the electronic device <NUM> according to an embodiment, the signal generator <NUM> may generate a transmitted signal as an arbitrary number of frames. Also, in <FIG>, some chirp signals are shown omitted. Thus, a relationship between frequency and time of a transmitted signal generated by the signal generator <NUM> may be stored in the storage <NUM>, for example.

Thus, the electronic device <NUM> according to an embodiment may transmit a transmitted signal consisting of a subframe including a plurality of chirp signals. Also, the electronic device <NUM> according to an embodiment may transmit a transmitted signal consisting of a frame including a predetermined number of subframes.

Hereinafter, the electronic device <NUM> will be described as transmitting a transmitted signal with a frame structure as shown in <FIG>. However, the frame structure as shown in <FIG> is an example, and a number of chirp signals included in one subframe is not limited to eight, for example. In an embodiment, the signal generator <NUM> may generate a subframe including an arbitrary number of (for example, any plural) chirp signals. Further, the subframe structure as shown in <FIG> is also an example. For example, a number of subframes included in one frame is not limited to <NUM>. In an embodiment, the signal generator <NUM> may generate a frame including an arbitrary number of (for example, any plural) subframes.

The synthesizer <NUM> shown in <FIG> raises a frequency of a signal generated by the signal generator <NUM> to a frequency in a predetermined frequency band. The synthesizer <NUM> may raise a frequency of a signal generated by the signal generator <NUM> to a frequency selected as a frequency of the transmitted wave T to be transmitted from the transmitting antenna <NUM>. The frequency to be selected as the frequency of the transmitted wave T to be transmitted from the transmitting antenna <NUM> may be set by the controller <NUM>, for example. Further, the frequency selected as the frequency of the transmitted wave T to be transmitted from the transmitting antenna <NUM> may be stored in the storage <NUM>, for example. The signal whose frequency has been raised by the synthesizer <NUM> is supplied to the phase controller <NUM> and the mixer <NUM>. When there are a plurality of receivers <NUM>, the signal whose frequency has been raised by the synthesizer <NUM> may be supplied to each of the mixer <NUM> of the plurality of receivers <NUM>.

The phase controller <NUM> controls a phase of a transmitted signal supplied by the synthesizer <NUM>. Specifically, the phase controller <NUM> may adjust a phase of a transmitted signal by appropriately advancing or delaying a phase of a signal supplied from the synthesizer <NUM> based on control by the controller <NUM>, for example. In this case, the phase controller <NUM> may adjust a phase of each transmitted signal based on path difference of each transmitted wave T to be transmitted from a plurality of transmitting antennas <NUM>. By the phase controller <NUM> appropriately adjusting the phase of each transmitted signal, the transmitted waves T to be transmitted from the plurality of transmitting antennas <NUM> intensify each other in a predetermined direction to form a beam (beamforming). In this case, a correlation between a beamforming direction, and phase amount to be controlled of transmitted signals respectively transmitted by a plurality of transmitting antennas <NUM> may be stored in the storage <NUM>, for example. The transmitted signal whose phase is controlled by the phase controller <NUM> is supplied to the amplifier <NUM>.

The amplifier <NUM> amplifies the power (electric power) of the transmitted signal supplied from the phase controller <NUM>, for example, based on control by the controller <NUM>. Because the technique itself for amplifying the power of the transmitted signal is already known, a more detailed description will be omitted. The amplifier <NUM> is connected to the transmitting antenna <NUM>.

The transmitting antenna <NUM> outputs (transmits) the transmitted signal amplified by the amplifier <NUM> as the transmitted wave T. As described above, the sensor <NUM> may be configured to include a plurality of transmitting antennas, such as the transmitting antenna 25A and the transmitting antenna 25B. Because the transmitting antenna <NUM> can be configured in the same manner as the transmitting antenna used for known radar technique, a more detailed description will be omitted.

In this way, the electronic device <NUM> according to an embodiment can transmit a transmitted signal (for example, transmitted chirp signal) as a transmitted wave T from the transmitting antenna <NUM>. Here, at least one of each functional part constituting the electronic device <NUM> may be housed in one enclosure. In this case, the one enclosure may be constructed so that it cannot be easily opened. For example, the transmitting antenna <NUM>, the receiving antenna <NUM>, and the amplifier <NUM> are preferably housed in one enclosure, and this enclosure may be constructed so that it cannot be easily opened.

Further, when the sensor <NUM> is installed on the mobile body <NUM> such as an automobile, the transmitting antenna <NUM> may transmit the transmitted wave T to outside the mobile body <NUM> through a cover member such as a radar cover. In this case, the radar cover may be made of a substance that allows electromagnetic waves to pass through, such as synthetic resin or rubber. This radar cover may be, for example, a housing of the sensor <NUM>. By covering the transmitting antenna <NUM> with a member such as the radar cover, risks that the transmitting antenna <NUM> is damaged or malfunctions due to contact with external objects can be reduced. Further, the radar cover and the housing described above may also be referred to as a radome (same as below).

The electronic device <NUM> shown in <FIG> comprises two transmitting antennas <NUM> such as the transmitting antenna 25A and the transmitting antenna 25B, and transmits the transmitted wave T by these two transmitting antennas <NUM>. Therefore, the electronic device <NUM> shown in <FIG> is also configured to include the two functional parts required to transmit the transmitted wave T from the two transmitting antennas <NUM>, respectively. Specifically, the electronic device <NUM> is configured to include two phase controllers <NUM> such as the phase controller 23A and the phase controller 23B. Further, the electronic device <NUM> shown in <FIG> is configured to include two amplifiers <NUM> such as the amplifier 24A and the amplifier 24B.

The electronic device <NUM> shown in <FIG> comprises two transmitting antennas <NUM>, but the number of transmitting antennas <NUM> comprised by the electronic device <NUM> according to an embodiment may be any plurality, for example, three or more. In this case, the electronic device <NUM> according to an embodiment may comprise the same number of amplifiers <NUM> as the plurality of transmitting antennas <NUM>. Further, in this case, the electronic device <NUM> according to an embodiment may comprise the same number of phase controllers <NUM> as the plurality of transmitting antennas <NUM>.

The receiving antenna <NUM> receives the reflected wave R. The reflected wave R is the one obtained by reflection of the transmitted wave T on the predetermined object <NUM>. The receiving antenna <NUM> may be configured to include a plurality of antennas, such as the receiving antenna 31A to the receiving antenna 31D. Because the receiving antenna <NUM> can be configured in the same manner as the receiving antenna used for the known radar technique, a more detailed description will be omitted. The receiving antenna <NUM> is connected to the LNA32. The received signal based on the reflected wave R received by the receiving antenna <NUM> is supplied to the LNA32.

The electronic device <NUM> according to an embodiment can receive the reflected wave R obtained by reflection of the transmitted wave T by a predetermined object <NUM>, transmitted as the transmitted signal (transmitted chirp signal) such as a chirp signal, from a plurality of the receiving antennas <NUM>. Thus, when the transmitted chirp signal is transmitted as the transmitted wave T, the received signal based on the received reflected wave R is referred to as a received chirp signal. That is, the electronic device <NUM> receives the received signal (for example, the received chirp signal) as the reflected wave R from the receiving antenna <NUM>. Here, at least one of functional parts constituting the electronic device <NUM> such as the plurality of the receiving antennas <NUM> may be housed in one enclosure. In this case, the one enclosure may be constructed so that it cannot be easily opened.

Further, when the sensor <NUM> is installed on the mobile body <NUM> such as an automobile, the receiving antenna <NUM> may receive the reflected wave R from outside the mobile body <NUM> through a cover member such as a radar cover. In this case, the radar cover may be made of a substance that allows electromagnetic waves to pass through, such as synthetic resin or rubber. This radar cover may be, for example, a housing of the sensor <NUM>. By covering the receiving antenna <NUM> with a member such as the radar cover, risks that the transmitting antenna <NUM> is damaged or malfunctions due to contact with external objects can be reduced.

Further, the sensor <NUM> may include, for example, all transmitting antennas <NUM> and all receiving antennas <NUM>. Further, when the receiving antenna <NUM> is installed near the transmitting antenna <NUM>, these antennas may be configured to be collectively included in one sensor <NUM>. That is, one sensor <NUM> may include, for example, at least one transmitting antenna <NUM> and at least one receiving antenna <NUM>. For example, one sensor <NUM> may include a plurality of transmitting antennas <NUM> and a plurality of receiving antennas <NUM>. In such a case, for example, one radar sensor may be covered by a member such as one radar cover.

The LNA <NUM> amplifies the received signal with low noise based on the reflected wave R received by the receiving antenna <NUM>. The LNA <NUM> may be used as a low noise amplifier (Low Noise Amplifier), and amplifies the received signal supplied from the receiving antenna <NUM> with low noise. The received signal amplified by the LNA <NUM> is supplied to the mixer <NUM>.

The mixer <NUM> generates a beat signal by mixing (multiplying) the received signal of the RF frequency supplied from the LNA <NUM> with the transmitted signal supplied from the synthesizer <NUM>. The beat signal mixed by the mixer <NUM> is supplied to the IF part <NUM>.

The IF part <NUM> decreases the frequency of the beat signal to an intermediate frequency (IF (Intermediate Frequency) frequency) by performing frequency conversion on the beat signal supplied from the mixer <NUM>. The beat signal whose frequency is decreased by the IF part <NUM> is supplied to the AD converter <NUM>.

The AD converter <NUM> digitizes the analog beat signal supplied from the IF part <NUM>. The AD converter <NUM> may be configured by any analog-to-digital conversion circuit (Analog to Digital Converter (ADC)). As shown in <FIG>, the beat signal digitized by the AD converter <NUM> shown in <FIG> is supplied to the distance FFT processor <NUM> of the controller <NUM>. When there are a plurality of receivers <NUM>, each beat signal digitized by the plurality of AD converters <NUM> may be supplied to the distance FFT processor <NUM>.

The distance FFT processor <NUM> shown in <FIG> can estimate the distance between the mobile body <NUM> equipped with the electronic device <NUM> and the object <NUM>, based on the beat signal supplied from the AD converter <NUM>.

The distance FFT processor <NUM> may include, for example, a processor that performs a fast Fourier transform. In this case, the distance FFT processor <NUM> may consist of an arbitrary circuit or a chip that performs the fast Fourier Transform (Fast Fourier Transform (FFT)) process. The distance FFT processor <NUM> may perform Fourier transforms other than the fast Fourier transform. For example, the distance FFT processor <NUM> may use a discrete Fourier transform or the like.

The distance FFT processor <NUM> performs a FFT process on the beat signal digitized by the AD converter <NUM> (hereinafter, appropriately referred to as "first distance FFT process"). For example, the distance FFT processor <NUM> may perform the FFT process on the complex signal supplied from the AD converter <NUM>. The beat signal digitized by the AD converter <NUM> can be represented as a time change of signal intensity (electric power). The distance FFT processor <NUM> performs the FFT process on such beat signals, whereby it can be expressed as the signal intensity (electric power) corresponding to each frequency. When the peak is equal to or higher than a predetermined threshold value in the result obtained by performing the first FFT process, the distance FFT processor <NUM> may determine that the predetermined object <NUM> exists at a distance corresponding to the peak. For example, such as the Constant False Alarm Rate (CFAR) detection process, when a peak value equal to or higher than the threshold value is detected in the average power or amplitude of the disturbance signal, a method to determine that there is an object (reflecting object) reflecting transmitted waves is known.

Thus, the electronic device <NUM> according to an embodiment detects the object <NUM> reflecting the transmitted wave T based on the transmitted signal, transmitted from the transmitting antenna as the transmitted wave T and the received signal, received from the receiving antenna <NUM> as the reflected wave R obtained by reflection of the transmitted wave T. Further, the electronic device <NUM> according to an embodiment may determine that the object <NUM> has been detected when the peak in the result obtained by performing the FFT process on the beat signal, generated based on the transmitted signal and the received signal, becomes equal to or higher than the predetermined threshold value.

The distance FFT processor <NUM> can estimate distance to a predetermined object based on one chirp signal (for example, c1 shown in <FIG>). That is, the electronic device <NUM> can measure (estimate) the distance L shown in <FIG> by performing the first FFT process. Because the technique itself for measuring (estimating) the distance to the predetermined object by performing the FFT process on the beat signal is known, a more detailed description will be simplified or omitted as appropriate. Results of the first FFT process performed by the distance FFT processor <NUM> may be supplied to the speed FFT processor <NUM>.

The speed FFT processor <NUM> estimates relative speed between the mobile body <NUM> equipped with the electronic device <NUM> and the object <NUM> based on the beat signal on which the first FFT process has been performed by the distance FFT processor <NUM>. The speed FFT processor <NUM> may include, for example, a processor for performing the fast Fourier transform. In this case, the speed FFT processor <NUM> may consist of an arbitrary circuit or a chip, configured to perform the fast Fourier Transform (Fast Fourier Transform (FFT)) process. The speed FFT processor <NUM> may perform Fourier transforms other than the fast Fourier transform.

The speed FFT processor <NUM> further performs a FFT process on the beat signal on which the first FFT process has been performed by the distance FFT processor <NUM> (hereinafter, appropriately referred to as "second FFT process"). For example, the speed FFT processor <NUM> may perform the FFT process on the complex signal supplied from the distance FFT processor <NUM>. The speed FFT processor <NUM> can estimate relative speed with a predetermined object based on the subframe of the chirp signal (for example, the subframe <NUM> shown in <FIG>). When the first FFT process is performed on the beat signal as described above, a plurality of vectors can be generated. The relative speed with a predetermined object can be estimated by obtaining a phase of the peak in the result obtained by performing the second FFT process on these plurality of vectors. That is, the electronic device <NUM> can measure (estimate) the relative speed between the mobile body <NUM> shown in <FIG> and the predetermined object <NUM> by performing the second FFT process. Because the technique itself for measuring (estimating) the relative speed with the predetermined object by performing the speed FFT process on the result obtained by performing the distance FFT process is known, more detailed description will be simplified or omitted as appropriate. The result obtained by performing the second FFT process by the speed FFT processor <NUM> may be supplied to the arrival angle estimator <NUM>.

The arrival angle estimator <NUM> estimates the direction in which the reflected wave R arrives from the predetermined object <NUM> based on the result obtained by the FFT process performed by the speed FFT processor <NUM>. The arrival angle estimator <NUM> can estimate the direction in which the reflected wave R arrives by receiving the reflected wave R from the plurality of receiving antennas <NUM>. For example, it is assumed that the plurality of receiving antennas <NUM> are arranged at predetermined intervals. In this case, the transmitted wave T transmitted from the transmitting antenna <NUM> is reflected by the predetermined object <NUM> and becomes the reflected wave R, and each of the plurality of receiving antennas <NUM> arranged at predetermined intervals respectively receives the reflected wave R. Then, the arrival angle estimator <NUM> can estimate the direction in which the reflected wave R arrives at the receiving antenna <NUM> based on the phase of the reflected wave R respectively received by each of the plurality of receiving antennas <NUM> and the path difference of each of the reflected waves R. That is, the electronic device <NUM> can measure (estimate) the arrival angle θ shown in <FIG> based on the result obtained by performing the second FFT process.

Various techniques for estimating the direction in which the reflected wave R arrives based on the result obtained by performing the speed FFT process have been proposed. For example, algorithms for estimating the direction in which the reflected wave arrives, such as MUSIC (Multiple Signal Classification), ESPRIT (Estimation of Signal Parameters via Rotational Invariance Technique) and the like are known. Therefore, more detailed description for known techniques will be simplified or omitted as appropriate. The information (angle information) of the arrival angle θ estimated by the arrival angle estimator <NUM> may be output to the clustering processor <NUM>. Further, the information output from the distance FFT processor <NUM> and the information output from the speed FFT processor <NUM> may also be output to the clustering processor <NUM>.

Further, the information of the arrival angle θ (angle information) estimated by the arrival angle estimator <NUM> may be output from the controller <NUM> to the ECU (Electronic Control Unit) or the like, for example. In this case, when the mobile body <NUM> is an automobile, communication may be performed using a communication interface such as CAN (Controller Area Network).

The determination processor <NUM> performs a process for determining whether each value used for the arithmetic processing is equal to or higher than a predetermined threshold value. For example, the determination processor <NUM> may determine whether the peaks in the results obtained by the process performed by the distance FFT processor <NUM> and the speed FFT processor <NUM> are equal to or higher than a predetermined threshold value, respectively.

For example, the determination processor <NUM> may determine whether the peak in the result obtained by performing the first FFT process by the distance FFT processor <NUM> is equal to or higher than the first threshold value. That is, the determination processor <NUM> may determine whether the peak in the result obtained by performing the first FFT process on the beat signal generated based on the transmitted signal and the received signal becomes equal to or higher than the first threshold value. To set the first threshold value will be described further below. In this way, if the peak in the result obtained by performing the first FFT process on the beat signal is determined to be equal to or higher than the first threshold value, the beat signal may be counted as the "first sample".

Further, for example, the determination processor <NUM> may determine whether the peak in the result obtained by the second FFT process performed by the speed FFT processor <NUM> becomes equal to or higher than the second threshold value. That is, the determination processor <NUM> may determine whether the peak in the result obtained by performing the second FFT process on the above-mentioned first sample becomes equal to or higher than the second threshold value. To set the second threshold value will be described later. In this way, when it is determined that the peak in the result obtained by performing the second FFT process on the first sample is equal to or higher than the second threshold value, the first sample may be counted as the "second sample".

As described above, the arrival angle estimator <NUM> estimates the direction in which the reflected wave R arrives from the predetermined object <NUM> based on the result obtained by the FFT process performed by the speed FFT processor <NUM>. Further, the speed FFT processor <NUM> performs the second FFT process on the beat signal on which the first FFT process has been performed by the distance FFT processor <NUM>. In this case, the distance FFT processor <NUM> may generate the first sample, according to the determination process by the determination processor <NUM>, based on the result obtained by performing the first FFT process on the beat signal generated based on the transmitted and received signals. Further, the speed FFT processor <NUM> may generate the second sample, according to the determination process by the determination processor <NUM>, based on the result obtained by performing the second FFT process on the first sample. Then, the arrival angle estimator <NUM> may estimate the arrival direction (arrival angle θ) of the reflected wave R based on the generated second sample. For example, the electronic device <NUM> may estimate the arrival direction (arrival angle θ) of the reflected wave R based on a covariance matrix obtained from the second sample.

The electronic device <NUM> shown in <FIG> comprises two transmitting antennas <NUM> and four receiving antennas <NUM>. Thus, by comprising a plurality of transmitting antennas <NUM> and a plurality of receiving antennas <NUM>, the electronic device <NUM> may use these antennas as a virtual antenna array of, for example, eight antennas. In this way, the electronic device <NUM> may transmit and receive the reflected wave R with the <NUM> subframes shown in <FIG> by using eight virtual antennas.

The clustering processor <NUM> performs a clustering process based on the output from at least one of the distance FFT processor <NUM>, the speed FFT processor <NUM>, and the arrival angle estimator <NUM>. As an algorithm used for clustering data, for example, DBSCAN (Density-based spatial clustering of applications with noise) is known. The information clustered by the clustering processor <NUM> may be output to the tracking processor <NUM>.

The tracking processor <NUM> performs a tracking process based on the output from the clustering processor <NUM>. As a method of tracking, a method such as a Kalman (Kalman) filter is known. The result obtained by the tracking process performed by the tracking processor <NUM> is supplied to the update processor <NUM>.

The information of the results obtained by tracking process performed by the tracking processor <NUM> may be output from the controller <NUM> to the ECU (Electronic Control Unit), for example. In this case, when the mobile body <NUM> is an automobile, communication may be performed using a communication interface such as CAN (Controller Area Network).

The update processor <NUM> updates each value related to the determination process to be performed by the determination processor <NUM>, based on the information of the result output from the tracking processor <NUM>. As described above, the determination processor <NUM> determines whether the peak in the result obtained by the FFT process performed by the distance FFT processor <NUM> and the speed FFT processor <NUM> is equal to or higher than a predetermined threshold value. The update processor <NUM> may update each value related to such determination process. The process of updating each value related to the determination process performed by the determination processor <NUM>, by the update processor <NUM> is described further below, along with the threshold values described above.

<FIG> are diagrams for explaining examples of operations of the electronic device <NUM> according to an embodiment. Hereinafter, an example of the operation of the electronic device <NUM> according to an embodiment will be described. Hereinafter, an example in which the electronic device <NUM> is configured as an FMCW radar of the millimeter wave method will be described.

<FIG> is a flowchart for explaining an operation of the electronic device <NUM> according to an embodiment. The operation shown in <FIG> may be started, for example, when the electronic device <NUM> detects a predetermined object <NUM> existing around the mobile body <NUM>.

When the operation shown in <FIG> starts, the controller <NUM> of the electronic device <NUM> firstly sets a threshold value to be used when the determination processor <NUM> performs the determination process (step S0).

<FIG> is a diagram for showing an example of a threshold value used for the determination processor <NUM> to perform determination process. Each threshold value shown in <FIG> may be stored in, for example, the determination processor <NUM> or the storage <NUM>. As shown in <FIG>, the determination processor <NUM> can set each threshold value for performing the determination process. In <FIG>, a threshold value of <NUM> dB to <NUM> dB is shown as an example of the threshold value Sth for performing the determination process. As described above, the threshold value Sth may be the first threshold value that is determined to be larger or smaller than the peak in the result obtained by the first FFT process performed by the distance FFT processor <NUM>. Further, as described above, the threshold value Sth may be the second threshold value that is determined to be larger or smaller than the peak in the result obtained by the second FFT process performed by the speed FFT processor <NUM>. That is, the threshold value Sth shown in <FIG> may be at least one of the first threshold value and the second threshold value described in detail. Further, the first threshold value and the second threshold value may be the same as or different from the threshold value Sth shown in <FIG>.

As shown in <FIG>, each value of the threshold value Sth corresponds to an object detection probability, respectively. This object detection probability is a value that is associated with the threshold Sth based on the determination of whether an object has been detected in the determination process by the determination processor <NUM> when the threshold Sth is used. For example, the object detection probability P (<NUM>) shown in <FIG> indicates the object detection probability [%] when the threshold value Sth is set to <NUM> dB. As shown in <FIG>, this object detection probability may be determined according to whether the object detection was successful or unsuccessful when the threshold Sth was used. For example, the success counts OK (<NUM>) shown in <FIG> indicates the number of times an object was determined to be detected when the threshold value Sth is <NUM> dB. Similarly, the failure counts NG (<NUM>) shown in <FIG> indicates the number of times an object was determined not to be detected when the threshold value Sth is set to <NUM> dB.

In step S0, the controller <NUM> may preferentially select the one with the highest object detection probability associated with each threshold value candidate when setting the threshold value Sth from among a plurality of threshold value candidates shown in <FIG> as the first and second threshold values. That is, in the electronic device <NUM> according to an embodiment, the predetermined threshold value Sth may be preferentially selected from among a plurality of threshold value candidates with a higher object detection probability P [%] associated with each of the plurality of threshold value candidates. Therefore, the determination processor <NUM> may use a scheduler that preferentially selects a threshold value Sth with a higher object detection probability, for example. The process of associating the object detection probability with each threshold value Sth will be described further below.

When the threshold value is set in step S0, the controller <NUM> controls the transmitter <NUM> to transmit the chirp signal from the transmitting antenna <NUM> (step S1). Specifically, the controller <NUM> instructs the signal generator <NUM> to generate transmitted signals (chirp signals). The controller <NUM> then controls so that the chirp signals are transmitted as transmitted waves T from the transmitting antenna <NUM> through the synthesizer <NUM>, the phase controller <NUM>, and the amplifier <NUM>.

When the chirp signal is transmitted in step S1, the controller <NUM> controls the receiver <NUM> to receive the chirp signal from the receiving antenna <NUM> (step S2). When the chirp signal is received in step S2, the controller <NUM> controls the receiver <NUM> to generate a beat signal by multiplying the transmitted chirp signal and the received chirp signal (step S3). Specifically, the controller <NUM> controls so that the chirp signal received from the receiving antenna <NUM> is amplified by the LNA <NUM> and multiplied with the transmitted chirp signal by the mixer <NUM>. The process from step S1 to step S3 may be performed, for example, by adopting a known millimeter wave FMCW radar technique.

When the beat signal is generated in step S3, the controller <NUM> generates the first sample described above from each generated chirp signal (step S4).

Hereinafter, the process of step S4 will be described further below. <FIG> is a flowchart for explaining the process of step S4 in <FIG> in more detail.

When the process of step S4 shown in <FIG> starts, the distance FFT processor <NUM> performs the first FFT process on the beat signal generated in step S3 as shown in <FIG> (step S11). As described above, when the process of step S11 is performed, the signal intensity (electric power) corresponding to each frequency is obtained. In step S11, the distance FFT processor <NUM> may perform the first FFT process on the digital beat signal supplied from the AD converter <NUM>.

When the first FFT process is performed on the beat signal in step S11, the determination processor <NUM> determines whether the peak in the result obtained by performing the first FFT process on the generated beat signal is equal to or higher than the first threshold value (step S12). Here, as described above, the first threshold value is the threshold value Sth set to be used when the determination processor <NUM> performs determination process in step S0.

Here, to set the first threshold value will be described. <FIG> is a diagram for explaining an example of setting the first threshold value.

<FIG> is a diagram for showing an example of the result obtained by performing the first FFT process on the beat signal in step S11, for example. In <FIG>, the horizontal axis represents the frequency f, and the vertical axis represents the signal intensity (electric power) S. In the example shown in <FIG>, when the frequency is in the region of fr1 and the frequency is in the region of fr2, the signal intensity shows a value close to Sa. Further, in the example shown in <FIG>, when the frequency is f1, the signal intensity shows the peak value S (f1).

In an embodiment, the determination processor <NUM> sets the power threshold value Sth so that, for example, the peak value S (f1) of the electric power can be detected. Here, the threshold value Sth may be set based on, for example, the average value of the electric power in the region fr1 and / or the region fr2 other than the peripheral region including the frequency f1 when the electric power reaches the peak value S (f1). For example, in <FIG>, when the frequencies are in the region fr1 and / or the region fr2, the average signal intensity shows a value close to Sa. Therefore, for example, the average value of the electric power in the region fr1 and / or the region fr2 other than the peripheral region including the frequency f1 when the electric power reaches the peak value S (f1) shall be Sa. In this case, by setting the average power value Sa plus a predetermined value as the power threshold value Sth, the electronic device <NUM> can detect an object such as a predetermined object <NUM>. Further, when setting the power threshold value Sth, the guard band may be excluded in the peripheral region including the frequency f1 when the electric power reaches the peak value S (f1).

In this way, by setting the power threshold value Sth, the determination processor <NUM> can determine whether the peak in the result obtained by performing the first FFT process on the beat signal is equal to or higher than the first threshold value.

In step S12 shown in <FIG>, it is determined whether the peak in the result obtained by performing the first FFT process on the beat signal is equal to or higher than the first threshold value. When it is determined in step S12 that the peak is equal to or higher than the first threshold value, the determination processor <NUM> performs the operation in step S13 and ends the process shown in <FIG>. On the other hand, when it is determined in step S12 that the peak is less than the first threshold value, the determination processor <NUM> ends the process shown in <FIG> without performing the operation in step S13.

In step S13, the determination processor <NUM> counts the beat signal on which it is determined that the peak in the results obtained by performing the first FFT process is equal to or higher than the first threshold value, as the first sample. For example, in step S13, the determination processor <NUM> may store the first sample in the storage <NUM>, the internal memory of the controller <NUM> or the like, for later process. In step S11, the beat signal on which the first FFT process is performed may be a unit of one chirp signal (for example, c1 shown in <FIG>), for example. Therefore, what is counted as the first sample in step S13 may be a unit of one chirp signal.

As described above, the distance FFT processor <NUM> may generate a first sample from one chirp signal in step S4 shown in <FIG>.

When the first sample is generated in step S4, the determination processor <NUM> determines whether the process of step S4 has been performed on all the chirp signals included in one subframe (step S5). In step S5, the determination processor <NUM> may determine whether the process of step S4 has been performed on eight chirp signals (for example, c1 to c8 shown in <FIG>) included in one subframe (for example, subframe <NUM> shown in <FIG>), for example.

If it is determined in step S5 that the process of step S4 has not yet been performed on some of the chirp signals included in one subframe, the controller <NUM> returns to step S1 and continues the process.

On the other hand, when it is determined in step S5 that the process of step S4 has been performed on all of the chirp signals in one subframe, the controller <NUM> performs the process in step S6. The case of proceeding to step S6 means that, for example, the first FFT process has been performed on all of eight chirp signals (c1 to c8) included in the subframe <NUM> shown in <FIG>. Then, when proceeding to step S6, among the above-mentioned eight chirp signals (c1 to c8), the one on which the peak in the result obtained by performing the first FFT process is equal to or higher than the first threshold value is counted as the first sample.

When it is determined in step S5 that the process of step S4 has been performed on all the chirp signals included in one subframe, the controller <NUM> generates the above-mentioned second sample from the generated first sample.

Hereinafter, the process of step S6 will be further described. <FIG> is a flowchart for explaining the process of step S6 in <FIG> in more detail.

When the process of step S6 shown in <FIG> starts, the speed FFT processor <NUM> performs a second FFT process on the first sample generated in step S4 as shown in <FIG> (step S21). In step S21, the speed FFT processor <NUM> may perform the second FFT process on the result obtained by the first FFT process performed by the distance FFT processor <NUM>.

After the second FFT process is performed in step S21, the determination processor <NUM> determines whether the peak in the result obtained by performing the second FFT process on the first samples on which the second FFT process has been performed becomes equal to or higher than the second threshold value (step S22). Here, the second threshold value is the threshold value Sth set to be used when the determination processor <NUM> performs the determination process in step S0 as described above.

Here, the second threshold value can be set in the same manner as the first threshold. That is, in an embodiment, the determination processor <NUM> may set the power threshold value S'th so that, for example, the peak value S'(f1) of the electric power can be detected. By setting the power threshold value S'th in the same manner as the first threshold value, the determination processor <NUM> can determine whether the peak in the result obtained by performing the second FFT process on the first sample is equal to or higher than the second threshold value.

In step S22 shown in <FIG>, it is determined whether the peak in the result obtained by performing the second FFT process on the first sample is equal to or higher than the second threshold value. When it is determined in step S22 that the peak is equal to or higher than the second threshold value, the determination processor <NUM> performs the operation in step S23 and ends the process shown in <FIG>. On the other hand, when it is determined in step S22 that the peak is less than the second threshold value, the determination processor <NUM> ends the process shown in <FIG> without performing the operation in step S23.

In step S23, the determination processor <NUM> counts the first sample for which it is determined that the peak in the result obtained by performing the second FFT process is equal to or higher than the second threshold value as the second sample. For example, in step S23, the determination processor <NUM> may store the second sample in the storage <NUM>, the internal memory of the controller <NUM> or the like for later processes. In step S21, the first sample on which the second FFT process is performed may be a unit of chirp signals (for example, c1 to c8 shown in <FIG>) included in one subframe, for example. Therefore, what is counted as the second sample in step S23 may be a unit of chirp signals included in one subframe.

As described above, the speed FFT processor <NUM> generates the second sample from the chirp signals included in one subframe in step S6 shown in <FIG>.

When the second sample is generated in step S6, the determination processor <NUM> determines whether the process of step S6 has been performed on the chirp signals of all the subframes included in one frame (step S7). In step S7, the determination processor <NUM> may determine whether the process of step S6 has been performed on all of the chirp signals of the <NUM> subframes (subframe <NUM> to subframe <NUM> shown in <FIG>) included in one frame (for example, frame <NUM> shown in <FIG>).

When it is determined in step S7 that some of the chirp signals included in one frame have not yet been processed in step S6, the controller <NUM> returns to step S1 and continues the process.

On the other hand, when it is determined in step S7 that the process of step S6 has been performed on the chirp signals of all the subframes included in one frame, the controller <NUM> performs the process of step S8. The case of proceeding to step S8 means that, for example, the second FFT process has been performed on the <NUM> subframes (subframes <NUM> to <NUM>) included in the frame <NUM> shown in <FIG>. Then, when proceeding to step S8, the first sample included in the above-mentioned <NUM> subframes in which the peak in the result obtained by performing the second FFT process is equal to or higher than the second threshold value is counted as the second sample.

In step S8, the arrival angle estimator <NUM> estimates the arrival direction (arrival angle θ) of the reflected wave R based on the generated second sample (step S8). In step S8, the arrival angle estimator <NUM> may estimate the arrival direction of the reflected wave R based on, for example, the covariance matrix obtained from the second sample. That is, in step S8, the arrival angle estimator <NUM> may estimate the arrival direction (arrival angle θ) of the reflected wave R reflected by a predetermined object <NUM> from the complex signals of the peaks of a plurality of antennas that satisfy the speed threshold (second threshold) value. For example, the covariance matrix for estimating the arrival direction (angle of arrival θ) may be obtained using the complex signal of the peak of the second sample in which the peak in the result obtained by performing the second FFT process on one frame (<NUM> subframes) of the transmitted signal described above is equal to or higher than the second threshold value.

When the arrival direction (arrival angle θ) is estimated in step <NUM>, the controller <NUM> performs the update process (step S9).

Here, the update process according to an embodiment will be described. <FIG> is a flowchart for explaining the process of step S9 in <FIG> in more detail.

When the process of step S9 shown in <FIG> starts, the clustering processor <NUM> performs a data clustering process as shown in <FIG> (step S31). In step S31, the clustering processor <NUM> may perform the clustering process based on the information of the distance to the predetermined object <NUM>, the information of the relative speed with the object <NUM>, and the information of the arrival direction (arrival angle θ) of the reflected wave R reflected by the predetermined object <NUM>. In step S31, as described above, the clustering processor <NUM> may perform the clustering process using an algorithm such as DBSCAN.

When the clustering process is performed in step S31, the tracking processor <NUM> performs the tracking process based on the result obtained by performing the clustering process (step S32). In step S32, the tracking processor <NUM> may perform the tracking process between frames, for example by Kalman filter, as described above.

When the tracking process is performed in step S32, the tracking processor <NUM> determines whether a cluster of a predetermined object <NUM> can be detected as a result of the tracking process (step S33). In step S33, if the tracking processor <NUM> can detect the cluster of the object <NUM>, it determines that the detection is successful (step S34). Specifically, the tracking processor <NUM> estimates the result of the n+<NUM>th frame from the clustering result up to the nth frame and the estimation result of the Kalman filter of the nth frame by calculating the Kalman filter. The tracking processor <NUM> uses this estimation result when the n + <NUM>th frame is not detected. The result determined to be detection success in step S34 may be supplied to the update processor <NUM>. On the other hand, in step S33, if the tracking processor <NUM> cannot detect the cluster of the object <NUM>, it determines that the detection has failed (step S35). The information of the result determined to be detection failure in step S35 may be supplied to the update processor <NUM>.

When the information of the result of the detection success or failure is supplied to step S34 or step S35, the update processor <NUM> updates the object detection probability shown in <FIG> (step S36). For example, when the threshold value Sth is set to <NUM> dB in step S0 and the cluster detection is successful in step S33 (step S34), the update processor <NUM> adds <NUM> to the number of success counts OK (<NUM>) shown in <FIG>, in step S36. Further, when the threshold value Sth is set to <NUM> dB in step S0 and the cluster detection fails in step S33 (step S35), the update processor <NUM> adds <NUM> to the number of failure counts NG (<NUM>) shown in <FIG>, in step S36. Then, the update processor <NUM> updates the object detection probability at the threshold value based on the increment of success or failure at each threshold value.

Hereinafter, for example, when <NUM> [dB] is selected as the threshold value Sth and the detection of the object <NUM> is successful, the process of updating the object detection probability corresponding to the threshold value Sth (<NUM> dB) will be described as a specific example.

The probability that the detection of the object <NUM> is successful is described as P (OK), and the conditional probability that the detection of the object <NUM> is successful when <NUM> [dB] is selected as the threshold value Sth is described as P (OK | <NUM>). In this case, the conditional probability P (OK | <NUM>) can be expressed by Bayes' theorem as in the following equation (<NUM>).

The value of the conditional probability P (OK I <NUM>) obtained as described above is updated as the value of the object detection probability P (<NUM>) when the threshold value Sth is <NUM> [dB]. That is, the next determination on whether to select <NUM> [dB] as the threshold Sth is done based on this object detection probability P (<NUM>).

Similarly, the conditional probability P (OK | X) in which the detection of the object <NUM> is successful when X [dB] is selected as the threshold value Sth can be obtained in the same manner. In this way, the corresponding object detection probability P (X) is updated for each threshold value Sth. When updating the object detection probability as such a conditional probability, if the object detection probability at any threshold Sth is updated, the object detection probability at the other threshold Sth can also be changed by changing the population of success counts or failure counts.

Thus, in the electronic device <NUM> of an embodiment, the object detection probability associated with each of the plurality of threshold candidates may be updated based on the determination of whether the object was successfully detected when the predetermined threshold Sth was set.

When the object detection probability is updated in step S36, the process shown in <FIG> ends, and the process in step S9 shown in <FIG> also ends. When the process shown in <FIG> ends, the electronic device <NUM> may restart the process shown in <FIG>. When the process shown in <FIG> starts again, the controller <NUM> sets a threshold value to be used by the determination processor <NUM> when performing the determination process. In step S0, the controller <NUM> sets the above-mentioned first threshold value and second threshold value based on the object detection probability updated in step S9 among the respective values shown in <FIG>. Also here, the determination processor <NUM> may use, for example, a scheduler that preferentially selects the threshold value Sth with a higher object detection probability. Using the threshold value Sth selected in this way, the electronic device <NUM> may calculate the distance and speed of the peaks that are equal to or higher than the threshold value by comparing the peaks in the results obtained by performing the FFT process with the threshold value, in the same manner as the operation described above. By such an operation, the electronic device <NUM> can dynamically update the threshold value to be compared with the peak in the result obtained by performing the FFT process.

As described above, the electronic device <NUM> according to the embodiment sets a predetermined threshold value Sth based on the object detection probability. Here, as shown in <FIG>, the predetermined threshold value Sth may be selected from a plurality of threshold value candidates, and the object detection probability may be associated with the plurality of threshold value candidates, respectively. Further, the predetermined threshold value Sth may be preferentially selected from among the plurality of threshold value candidates with a higher object detection probability P [%] respectively associated with each of the plurality of threshold value candidates. Further, in the electronic device <NUM> according to an embodiment, when the object detection probabilities respectively associated with the plurality of threshold candidates are updated, a predetermined threshold Sth may be set based on the updated object detection probabilities.

Further, the electronic device <NUM> according to an embodiment may determine whether the detection of the object <NUM> is successful based on the result obtained by performing the clustering process on the result obtained by performing the fast Fourier transform process on the beat signal described above. Here, the electronic device <NUM> according to an embodiment may determine that the detection of the object <NUM> is successful when it is determined that the object <NUM> exists as a result obtained by performing the clustering process. On the other hand, the electronic device <NUM> according to an embodiment may determine that the detection of the object <NUM> has not been successful when it is estimated that the object <NUM> exists as a result obtained by performing the tracking process on the result obtained by performing the clustering process.

According to the electronic device <NUM> of an embodiment, when setting a threshold value of, for example, a constant false alarm rate (CFAR) for determining that an object has been detected, it is possible to preferentially select the threshold value with a higher object detection probability. Further, according to the electronic device <NUM> of an embodiment, it is possible to update, for example, a constant false alarm rate corresponding to the above-mentioned threshold value based on the results obtained by performing the clustering process and the tracking process when detecting a predetermined object.

Generally, in a technique such as radar, a disturbance signal depends on a surrounding object. Therefore, if the threshold value used for detecting the object is fixed, it is assumed that the object cannot be detected. An electronic device according to an embodiment can be dynamically controlled so that the threshold value with the highest statistical probability of successful detection is set. Therefore, according to an electronic device of an embodiment, it is possible to respond to changes in the surrounding environment and reduce the probability that the object will not be detected.

As described above, according to the electronic device <NUM> of an embodiment, the object reflecting transmitted waves can be detected with high accuracy.

The present disclosure has been described based on the drawings and examples, but it should be noted that those skilled in the art will find it easy to make various variations or modifications based on the present disclosure. Therefore, it should be noted that these variations or modifications are included in the scope of this disclosure. For example, the functions included in each functional part and the like can be rearranged in a logically consistent manner. A plurality of functional parts and the like may be combined into one or divided. Each of the embodiments according to the present disclosure described above is not limited to faithful implementation of each of the described embodiments, but may be implemented by combining or omitting some of the features as appropriate. That is, the contents of the present disclosure can be subjected to various variations and modifications based on the present disclosure by those skilled in the art. Therefore, these variations and modifications are included in the scope of this disclosure. For example, in each embodiment, each functional part, each means, each step and the like can be added to other embodiments in a logically consistent manner, or can be replaced with each functional part, each means, each step and the like of other embodiments. Further, in each embodiment, the plurality of each functional part, each means, each step and the like can be combined into one or divided. Each of the embodiments of the present disclosure described above is not limited to faithful implementation of each of the described embodiments, and may be implemented by combining or omitting some of the features as appropriate.

In the embodiment described above, an example of updating the object detection probability associated with each of the plurality of candidates of the threshold value Sth shown in <FIG> has been described. Further, in the embodiment described above, an example of dynamically changing the first threshold value and / or the second threshold value based on the object detection probability updated in this way has been described. However, in the electronic device <NUM> according to an embodiment, it is not necessary to dynamically change the first threshold value and / or the second threshold value based on the object detection probability updated as described above. For example, in the electronic device <NUM> according to an embodiment, the threshold value with the highest object detection probability P [%] associated with each of the plurality of threshold value candidates may be selected from among the plurality of threshold value candidates, and the threshold value may be fixed and used. Further, in the electronic device <NUM> according to an embodiment, after the first threshold value and / or the second threshold value is set once, the set threshold value may be changed based on a predetermined condition such as a change in an environment. Also in this case, in the electronic device <NUM> according to an embodiment, the threshold value with the highest object detection probability P [%] associated with each of the plurality of threshold value candidates may be selected from among the plurality of threshold value candidates.

Further, the plurality of threshold candidates as shown in <FIG> can update the object detection probability associated with the threshold value by, for example, selecting a threshold value other than the threshold value with the highest object detection probability P [%]. Therefore, in the electronic device <NUM> according to an embodiment, for example, under a predetermined condition such as during a test driving, the threshold value with the highest object detection probability P [%] associated with each of the plurality of threshold value candidates may not be intentionally selected. For example, the electronic device <NUM> of an embodiment may use the threshold value with the second highest object detection probability P[%] associated with each of the plurality of threshold value candidates, the third highest threshold value, or the lowest threshold value. That is, under a predetermined condition, the electronic device <NUM> according to an embodiment may select the predetermined threshold value described above, from among a plurality of threshold value candidates, other than a threshold value with a highest object detection probability associated with each of the plurality of threshold candidates.

The embodiment described above is not limited to implementation only as an electronic device <NUM>. For example, the embodiment described above is implemented as a method for controlling devices such as the electronic device <NUM>. Furthermore, for example, the embodiments described above is implemented as a control program for devices such as the electronic device <NUM>. In addition, the contents of the present disclosure may be variated and modified by those skilled in the art based on the present disclosure. Therefore, these variations or modifications are included in the scope of this disclosure. For example, in each embodiment, each functional part, each means, each step and the like can be added to other embodiments in a logically consistent manner, or can be replaced with each functional part, each means, each step and the like of other embodiments. Further, in each embodiment, the plurality of each functional part, each means, each step and the like can be combined into one or divided. Each of the embodiments of the present disclosure described above is not limited to faithful implementation of each of the described embodiments, and may be implemented by combining or omitting some of the features as appropriate.

Claim 1:
An electronic device (<NUM>), configured to:
detect an object (<NUM>) reflecting transmitted waves based on transmitted signals transmitted from a transmitting antenna (<NUM>) as the transmitted waves and received signals received from a receiving antenna (<NUM>) as reflected waves obtained by reflection of the transmitted waves;
determine that the object (<NUM>) has been detected when a peak in a result obtained by performing a Fourier transform process on beat signals generated based on the transmitted signals and the received signals is equal to or higher than a predetermined threshold value;
determine whether a cluster etection of the object (<NUM>) has been successful based on a result obtained by performing a clustering process and a tracking process based on the result obtained by performing the clustering process, on the result obtained by performing the Fourier transform process on the beat signal;
update an object detection probability at a threshold value candidate based on whether the cluster detection of the object (<NUM>) has been successful; and
select a predetermined threshold value based on the object detection probability.