JP2013079890A - Radar system and object derivation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for preventing a number of components of a radar system from increasing and suppressing heat generation.SOLUTION: A detection point related to an object is derived in one signal processing period based on a first transmission wave and a second transmission wave having a prescribed period and a first reflection wave in which the first transmission wave is reflected on the object and a second reflection wave in which the second transmission wave is reflected on the object. When prescribed conditions are satisfied, the detection point is derived in one signal processing period based on the first transmission wave changed into a specified period longer than the prescribed period and the first reflection wave, and the detection point is derived in the next signal processing period based on the second transmission wave changed into the specified period and the second reflection wave. As a result, the heat generation of the radar system can be suppressed almost without delaying deriving processing for the angle of the object.

Description

  The present invention relates to object derivation of a radar apparatus.

  Conventionally, when a transmission wave is output from an antenna of a radar apparatus, the output time of the transmission wave of a predetermined period is made relatively long, thereby improving the object derivation accuracy. In addition, after receiving the reflected wave, which is the transmission wave reflected from the object, by the antenna, the signal processing device of the radar apparatus derives the position of the object and the like based on the reflected wave and the transmission wave. In order to update information such as the position of the object that changes with time at an early timing, the object derivation period of the signal processing device is set to a relatively short period.

  However, if the output time of the transmission wave output from the antenna is lengthened, the power consumption of each device inside the radar device increases and heat is generated, so that the temperature inside the radar device rises and the accuracy of derivation of the object of the radar device is increased. There were times when it fell.

  Further, by setting the object derivation cycle of the signal processing device to a short cycle, the operation timing of the signal processing device that operates intermittently is advanced. As a result, the power consumption of the signal processing device is increased and heat is generated, so that the temperature inside the radar device rises and the object derivation accuracy of the radar device is sometimes lowered.

  In such a case, a heat radiating member is provided in the radar device in order to suppress heat generation inside the radar device and lower the temperature. Specifically, a heat radiating sheet or the like is provided on each substrate inside the radar device to improve the thermal conductivity to the housing of the radar device, or a heat radiating fin is provided on the housing to lower the temperature inside the radar device. It was.

Japanese Patent Laid-Open No. 7-177055

  However, providing a heat radiating member in the radar apparatus leads to an increase in manufacturing cost. In addition, for example, when a radar device is mounted on a vehicle, it is necessary to reduce the size of the radar device with the increase in the number of functions of the vehicle. There was a case.

  The present invention provides a technique for preventing an increase in the number of parts of a radar apparatus and suppressing heat generation.

  In order to solve the above-described problem, the present invention provides a radar apparatus that derives at least an angle of a detection point related to an object, the first transmission means for outputting a first transmission wave at a predetermined period, and a first transmission unit at the predetermined period. A second transmission means for outputting two transmission waves at a timing different from a timing for outputting the first transmission wave; a first reflected wave reflected by the detection point at the first transmission wave; Based on the receiving means for receiving the second reflected wave reflected by the detection point, the first transmission wave and the second transmission wave, and the first reflected wave and the second reflected wave, the angle of the detection point is determined. Derivation means for performing a first derivation process for deriving, wherein the first transmission means outputs the first transmission wave at a specific period that is longer than the predetermined period when a predetermined condition is satisfied, The second transmission means satisfies the predetermined condition In addition, the second transmission wave is output at the specific period, and the second transmission wave is at a substantially intermediate timing between one output timing of the first transmission wave transmitted at the specific period and the next output timing. The derivation means derives the angle of the detection point based on the first transmission wave and the first reflected wave instead of the first derivation process when the predetermined condition is satisfied, and Then, a second derivation process for deriving an angle of the detection point based on the second transmission wave and the second reflected wave is performed.

  According to the present invention, in the radar device according to claim 1, the specific period is twice the predetermined period.

  Furthermore, in the radar apparatus according to claim 1 or 2, the beam pattern of the first transmission wave is a beam pattern different from the beam pattern of the second transmission wave, and the derivation unit includes: In accordance with a signal level difference between the signal level of the first reflected wave and the signal level of the second reflected wave, a loopback determination is performed to determine whether the detection point exists at the angle, When performing the first derivation process, when performing the return determination based on the first reflected wave and the second reflected wave received by the receiving means within the predetermined period, and when performing the second derivation process The return determination is performed based on the first reflected wave and the second reflected wave received by the receiving means within the specific period.

  According to the present invention, the derivation means is changed to a specific period whose transmission cycle is longer than the predetermined period when the predetermined condition is satisfied, and instead of the first derivation means, the first transmission wave and the first reflected wave are changed. The object angle derivation process is almost delayed by performing the second derivation process for deriving the detection point angle based on the second transmission wave and deriving the detection point angle based on the second transmission wave and the second reflected wave. Therefore, the heat generation of the radar device can be suppressed.

  Further, according to the present invention, the specific period is twice the predetermined period, so that the processing load of the radar apparatus is not increased and the processing speed of the object derivation is hardly decreased. Heat generation can be suppressed.

  Further, according to the present invention, the derivation means determines whether or not there is a detection point at an angle according to a signal level difference between the signal level of the first reflected wave and the signal level of the second reflected wave. When the first derivation process is performed and the first derivation process is performed, the wrapping determination is performed based on the first reflected wave and the second reflected wave received by the receiving unit within a predetermined period, and the second derivation process is performed. In the case of performing the return determination based on the first reflected wave and the second reflected wave received by the receiving means within the specific period, the timing for performing the return determination so that the control of the vehicle is hardly affected. It is possible to suppress the heat generation of the radar device by delaying.

FIG. 1 is a diagram illustrating a structure of a radar apparatus. FIG. 2 is a diagram mainly showing a block diagram of the radar apparatus. FIG. 3 is a time chart showing timing related to the first derivation process. FIG. 4 is a diagram illustrating an FM-CW method signal related to the first derivation process. FIG. 5 is a time chart showing timing related to the second derivation process. FIG. 6 is a diagram illustrating an FM-CW method signal related to the second derivation process. FIG. 7 is a process flowchart of the signal processing apparatus. FIG. 8 is a process flowchart of the signal processing apparatus. FIG. 9 is a process flowchart of the signal processing apparatus. FIG. 10 is a diagram illustrating an angular spectrum of detection points related to an object. FIG. 11 is a diagram illustrating beam patterns of the first transmission wave and the second transmission wave. FIG. 12 is a diagram showing reception levels in two types of beam patterns.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are exemplifications, and do not limit the technical scope of the present invention.

<First Embodiment>
<1. Structure of radar device>
FIG. 1 is a diagram illustrating the structure of the radar apparatus 1. The radar apparatus 1 of FIG. 1 mainly includes a radome 2, an antenna substrate 3, an antenna chassis 4, an RF chassis 5, an RF substrate 6, a baseband substrate 7, and a case 8.

  The radar apparatus 1 outputs a transmission wave from a transmission antenna (for example, the transmission antenna 13 shown in FIG. 2), and receives a reflected wave reflected from the object by the reception antenna (for example, the reception antenna 14 shown in FIG. 2). Then, the angle of the object is derived.

  The radome 2 is a member that protects the antenna substrate 3 and is made of, for example, resin. The radome 2 transmits a transmission wave output from the transmission antenna 13 provided on the antenna substrate 3 and a reflected wave from a detection point related to an object provided on the antenna substrate 3 and received by the reception antenna 14.

  The antenna substrate 3 includes a transmission antenna 13 and a reception antenna 14. Then, the transmission wave output from the transmission antenna 13 is reflected by the detection point, and the reception antenna 14 receives the reflected wave from the detection point. Further, the transmitting antenna 13 and the receiving antenna 14 of the antenna substrate 3 are constituted by planar antennas made of a printed circuit board having microstrip lines.

  The antenna substrate 3 is provided with at least one of the increase of the output time within one cycle of the transmission wave from the transmission antenna 13 provided on the antenna substrate 3 and the shortening of the output cycle. The power consumption of each part such as the transmission antenna 13 increases. As a result, each part such as the transmission antenna 13 generates heat, and the temperature of the radar apparatus 1 rises, so that the object derivation accuracy may be reduced.

  The antenna chassis 4 is surface-connected to the antenna substrate 3 and supports the antenna substrate 3. The RF chassis 5 is surface-connected to the RF substrate 6 and supports the RF substrate 6.

  The RF substrate 6 includes a signal generation unit (for example, the signal generation unit 11 illustrated in FIG. 2), an oscillator (for example, the oscillator 12 illustrated in FIG. 2), and a mixer (for example, the mixer 15 illustrated in FIG. 2). When at least one of the operation time and the operation frequency of each device such as the signal generation unit 11 of the RF substrate 6 increases, the power consumption of each of these devices increases. As a result, each of these devices generates heat, and the temperature of the radar device 1 increases, so that the accuracy of derivation of the object may decrease.

  The baseband substrate 7 mainly includes an AD (Analog to Digital) converter (for example, the AD converter 16 shown in FIG. 2) and a signal processing device (for example, the signal processing device 10 shown in FIG. 2). . And the power consumption of the signal processing apparatus 10 increases by performing at least one of the increase in the processing time within one period of the signal processing apparatus 10 and the shortening of the processing period. As a result, the signal processing apparatus 10 generates heat, and the temperature of the radar apparatus 1 increases, so that the object derivation accuracy may decrease.

  The case 8 is a housing that houses the antenna substrate 3, the antenna chassis 4, the RF chassis 5, the RF substrate 6, and the baseband substrate 7, and is made of, for example, metal.

<2. Block diagram>
FIG. 2 is a diagram mainly showing a block diagram of the radar apparatus 1. The radar apparatus 1 is mounted on, for example, a vehicle (for example, the vehicle 19 shown in FIG. 11), and derives detection points related to objects such as other vehicles around the vehicle 19. The detection point derivation result is transmitted to a vehicle control device (for example, the vehicle control device 100 shown in FIG. 2) that outputs a control signal to each part of the vehicle 19, the adjustment of the accelerator opening of the vehicle 19, and the vehicle 19 It is used for controlling the vehicle 19 such as tightening a seat belt worn by a user.

  The radar device 1 mainly includes a signal processing device 10, a signal generation unit 11, an oscillator 12, a transmission antenna 13, a reception antenna 14, a mixer 15, an AD converter 16, and an internal temperature sensor 21.

  Based on the transmission signal corresponding to the transmission wave output from the transmission antenna 13 and the reception signal corresponding to the reflected wave received by the reception antenna 14, the signal processing device 10 detects the angle of the detection point related to the object (for example, The angle of the detection point with respect to the vehicle 19 on which the radar apparatus 1 shown in FIG. 11 is mounted is derived. In addition to the angle of the detection point, the signal processing device 10 derives the distance of the detection point with respect to the vehicle 19 and the relative speed of the detection point with respect to the vehicle 19.

  Further, the signal processing device 10 indicates that the sensor information output from at least one of the internal temperature sensor 21 and the vehicle speed sensor 22 described later satisfies a predetermined condition, that is, the internal temperature of the radar device indicates a high temperature. When the temperature (for example, 90 ° C. or higher) is reached, control is performed to change the output period of the transmission wave output from the transmission antenna 13 to a specific period that is longer than a predetermined period. Then, when the sensor information satisfies a predetermined condition, the signal processing device 10 changes the detection point derivation processing method from one processing method to another processing method. The change of the output cycle and the change of the derivation processing method will be described in detail later.

  The signal generation unit 11 generates a modulation signal whose voltage changes in a triangular wave shape based on a control signal from the transmission control unit 107 described later.

  The oscillator 12 frequency-modulates a signal in a predetermined frequency band (for example, 76.5 GHz) based on the modulation signal generated by the signal generation unit 11 and outputs the signal to the transmission antenna 13 as a transmission signal.

  The transmission antenna 13 outputs a transmission wave corresponding to the transmission signal to the outside of the vehicle 19. The radar apparatus 1 has two transmission antennas, a transmission antenna 13a and a transmission antenna 13b. The transmitting antenna 13a and the transmitting antenna 13b have different antenna pattern shapes. Therefore, as will be described in detail later, a beam pattern of a transmission wave output from the transmission antenna 13a (hereinafter also referred to as “first transmission wave”) and a transmission wave output from the transmission antenna 13b (hereinafter referred to as “the first transmission wave”). The beam pattern is also different from the beam pattern of “2 transmission waves”.

  In addition, the transmission antennas 13 a and 13 b are switched in connection with the oscillator 12 at a predetermined period by switching of a switching unit 131 described later, and a transmission wave is output from the transmission antenna connected to the oscillator 12 to the outside of the vehicle 19. The Therefore, the output timing of the first transmission wave is different from the output timing of the second transmission wave.

  The switching unit 131 is a switch that switches the connection between the oscillator 12 and the transmission antenna 13, and connects either the transmission antenna 13 a or the transmission antenna 13 b to the oscillator 12 according to a control signal from the transmission control unit 107. To do.

  The reception antenna 14 is a plurality of array antennas that receive the reflected waves that are reflected from the detection points by the transmission waves transmitted from the transmission antenna 13. Specifically, the reception antenna 14 receives a reflected wave (hereinafter also referred to as “first reflected wave”) reflected by the detection point of the first transmission wave. Then, the receiving antenna 14 receives a reflected wave (hereinafter also referred to as “second reflected wave”) reflected from the detection point by the second transmission wave output from the transmission antenna 13b at a timing different from that of the first transmission wave. . In this embodiment, four reception antennas 14a (ch1), 14b (ch2), 14c (ch3), and 14d (ch4) are provided. Note that the receiving antennas 14a to 14d are arranged at equal intervals.

  The mixer 15 is provided for each receiving antenna (mixers 15a to 15d). The mixer 15 mixes the reception signal and the transmission signal. Then, a beat signal as a difference between the transmission signal and the reception signal is generated by mixing the reception signal and the transmission signal. The beat signal is output to the AD converter 16.

  The AD converter 16 samples a beat signal, which is an analog signal, at a predetermined period, and derives a plurality of sampling data. The sampled data is quantized, and the beat signal of analog data is converted into digital data. Then, the AD converter 16 outputs the converted digital data to the signal processing device 10. The AD converter 16 is also provided for each receiving antenna (AD converters 16 a to 16 d) similarly to the mixer 15.

  The signal processing apparatus 10 mainly has functions of a processing change unit 101, a Fourier transform unit 102, a peak extraction unit 103, an angle calculation unit 104, a distance / relative speed calculation unit 105, a loopback determination unit 106, and a transmission control unit 107. I have. Each function will be described below.

  When the sensor information from the internal temperature sensor 21 or the like satisfies a predetermined condition, the process changing unit 101 outputs a first transmission wave output at a predetermined cycle (for example, a 40 ms cycle) and a second output at a predetermined cycle. A control signal for changing the output period of the transmission wave from a predetermined period to a specific period (for example, 80 ms period) longer than the predetermined period is output to the transmission control unit 107. For example, when the internal temperature of the radar apparatus 1 detected by the internal temperature sensor 21 exceeds 90 ° C., transmission control of a control signal for changing the output period of the transmission wave of the transmission antenna 13a and the transmission antenna 13b from 40 ms to 80 ms is performed. Output to the unit 107.

  In addition, when the sensor information satisfies a predetermined condition, the processing change unit 101 changes the output timing of the second transmission wave output from the transmission antenna 13b immediately after the first transmission wave is output from the transmission antenna 13a to another Change to output timing. For example, the transmission control unit changes the control signal to be changed so as to output the second transmission wave at a substantially intermediate timing between the output timing of one first transmission wave from the transmission antenna 13a and the output timing of the next first transmission wave. It outputs to 107.

  Further, the process changing unit 101 derives an angle of the detection point based on the first transmission wave and the second transmission wave, and the first reflected wave and the second reflection when the sensor information satisfies a predetermined condition. (Hereinafter, it is also referred to as “first derivation process”.) The derivation process described below is changed. That is, the process changing unit 101 derives an angle of the detection point based on the first transmission wave and the first reflected wave, and derives an angle of the detection point based on the second transmission wave and the second reflected wave ( Hereinafter, it is also referred to as “second derivation process”.

  Here, the second derivation process is a first derivation process for deriving a detection point based on the first transmission wave and the second transmission wave, and the first reflected wave and the second reflected wave in one cycle of processing. Unlike the above, detection points are derived as follows. That is, the detection point angle is derived based on the first transmission wave and the first reflected wave in one cycle, and the detection point is based on the second transmission wave and the second reflected wave in the next cycle of one cycle. The angle derivation process is performed. As described above, the detection angle of the detection point based on the first transmission wave and the first reflection wave, and the second transmission wave and the second reflection wave is performed at different processing timings, thereby performing the object angle derivation process. Heat generation of the radar apparatus 1 can be suppressed with almost no delay.

  In addition, the process changing unit 101 changes the processing timing for determining whether or not a detection point by the return determination unit 106 described later exists at an angle derived from the first derivation process to the second derivation process. To do. As a result, the heat generation of the radar apparatus 1 can be suppressed by delaying the timing of the return determination so that the control of the vehicle 19 is hardly affected. Note that details of the change in the processing timing of the return determination unit 106 will be described later.

  The Fourier transform unit 102 performs a fast Fourier transform process on the digital data output from the AD converter 16. Thereby, the conversion data which shows the signal level on the basis of a frequency is acquired.

  The peak extraction unit 103 extracts a signal whose signal level exceeds a predetermined threshold (hereinafter referred to as “peak signal”) from the data signal converted by the Fourier transform unit 102.

  The angle calculation unit 104 calculates the angle of the detection point related to the object based on the information of the peak signal. For the calculation of the angle, for example, an algorithm such as ESPRIT is used that estimates the angle of the detection point using the phase difference of the reception signals at the reception antennas 14a to 14d. Then, the angle of the detection point is calculated based on the eigenvalue of the correlation matrix and the eigenvector.

The distance / relative speed calculation unit 105 performs pairing between the peak in the section where the frequency increases and the peak in the section where the frequency decreases based on the peak information in the conversion data, and detects the detection point based on the paired peak frequency. Information on the distance from the vehicle 19 on which the radar device 1 is mounted and information on the relative speed between the detection point and the vehicle 19 are calculated. Here, the distance is obtained by the following equation (1), and the relative speed is obtained by the following equation (2). R is the distance, fup is the frequency of the peak signal in the section where the frequency is increased, fdn is the frequency of the peak signal in the section where the frequency is decreased, ΔF is the modulation width (for example, 200 MHz) of the transmission wave, fm is the modulation frequency, f ₀ is the center frequency (for example, 76.5 GHz), and c is the propagation speed of the transmission wave.

また、相対速度は次の数式により導出され、Ｖは相対速度を示す。

The relative speed is derived by the following formula, and V indicates the relative speed.

折り返し判定部１０６は、角度演算部１０４で演算された検知点の角度に当該検知点が存在するか否か、換言すれば検知点の角度に位相折り返しが生じているか否かを判定する。即ち、各受信アンテナにおける受信波の位相差を基に検知点の角度を推定する場合、受信波の位相差がｎ°の場合とｎ＋３６０°の場合とを区別できず、どちらであってもｎ°と推定してしまう。

The return determination unit 106 determines whether or not the detection point exists at the angle of the detection point calculated by the angle calculation unit 104, in other words, whether or not phase return occurs at the angle of the detection point. That is, when the angle of the detection point is estimated based on the phase difference of the received wave at each receiving antenna, the case where the phase difference of the received wave is n ° and n + 360 ° cannot be distinguished. It is estimated to be °.

  For example, when the phase difference of the received wave is 360 °, the detection point exists at a position having an angle of about 47 ° from the front of the host vehicle, but the calculation result in the angle calculation unit 104 is 0 °. That is, if a detection point exists in front of the host vehicle, it will be erroneously detected. Therefore, the beam pattern of the first transmission wave output from the transmission antenna 13a and the beam pattern of the second transmission wave output from the transmission antenna 13b in order to determine whether or not this phase folding has occurred are different beam patterns. Yes.

  Even if the reflected waves are from the same object due to the difference in the beam pattern, the signal levels of the first reflected wave and the second reflected wave differ depending on the angle at which the object exists. In this way, in accordance with the signal level difference of each reflected wave corresponding to a plurality of transmission waves having different beam patterns, it is determined whether or not phase wrapping has occurred in the angle of the detection point calculated by the angle calculation unit 104, and Determine certainty.

  The transmission control unit 107 outputs a control signal for generating a modulation signal to the signal generation unit 11. That is, the output periods of the first transmission wave and the second transmission wave shown in FIGS. 3, 4, 5, and 6, which will be described later, are controlled according to the process change status of the process change unit 101. Note that the output periods of the first transmission wave and the second transmission wave are changed by the control signal of the process changing unit 101. Further, the transmission control unit 107 controls switching of the transmission antenna 13 of the switching unit 131. That is, the transmission signal output from the oscillator 12 is determined as a transmission wave to be transmitted from the transmission antennas 13 a and 13 b to the outside of the vehicle 19.

  The internal temperature sensor 21 is a sensor provided in the radar apparatus 1. The internal temperature sensor 21 is a sensor that detects the temperature of each device inside the radar device 1, and outputs temperature information inside the radar device 1 to the signal processing device 10.

  The vehicle speed sensor 22 is a sensor provided in the vehicle 19. The vehicle speed sensor 22 outputs a vehicle speed pulse indicating the traveling speed of the vehicle 19 to the signal processing device 10 of the radar device 1.

  The vehicle control device 100 receives information on the angle, distance, and relative speed of the detection point from the radar device 1, adjusts the accelerator opening of the vehicle 19 according to the received information, and the user of the vehicle 19 A control signal for tightening the seat belt to be mounted is output to each part of the vehicle.

<3. Time chart for first derivation process>
FIG. 3 is a time chart showing timing related to the first derivation process. FIG. 3 illustrates the timing of starting and ending output of transmission waves from the transmission antenna 13a and the transmission antenna 13b, the timing of reception start and reception of reflected waves from the reception antenna 14, and the object derivation process of the signal processing device 10. The timing of starting and ending is shown.

  More specifically, the signal S1 in FIG. 3 is a signal having a predetermined cycle T1 (for example, 40 ms cycle), and is a signal indicating the timing of the output start and output end of the first transmission wave. The signal S2 is a signal having the same predetermined period T1 as that of the signal S1, and is a signal indicating the output start timing and output end timing of the second transmission wave. The signal S3 is a signal having the same predetermined period T1 as the signals S1 and S2, and is a signal indicating the timing of the reception start and reception end of the reflected wave of the reception antenna 14. Further, the signal S4 is a signal having the same predetermined cycle T1 as the signals S1 to S3, and is a signal indicating the start and end timings of the object derivation process of the signal processing device 10. Hereinafter, the processing timing of each signal will be described in detail.

  The signal S1 is turned on at time t1, and is turned off at time t2 after time t1. That is, the output of the first transmission wave starts at time t1 and ends at time t2. The signal S1 is turned on for the second time at time t6, and is turned off at time t7 after time t6. In this way, the signal S1 repeats ON and OFF states at a predetermined cycle (for example, 40 ms cycle) T1 from time t1 to time t6.

  The signal S2 is turned on at time t2, and is turned off at time t3 after time t2. That is, the output of the second transmission wave starts at time t2 and ends at time t3. Further, the signal S2 is turned on for the second time at time t7, and is turned off at time t8 after time t7. In this way, the signal S2 repeats ON and OFF states at a predetermined cycle (for example, 40 ms cycle) T1 from time t2 to time t7.

  The signal S3 is turned on at time t1, and turned off at time t4 after time t3. That is, reception of the first reflected wave and the second reflected wave of the receiving antenna 14 starts at time t1 and ends at time t4. The signal S3 is turned on for the second time at time t6, and is turned off at time t9 after time t8. In this way, the signal S3 repeats ON and OFF at a predetermined cycle (for example, 40 ms cycle) T1 from time t1 to time t6.

  The signal S4 is turned on at time t1, and is turned off at time t5 after time t4. That is, the detection point angle, distance, and relative velocity based on the first transmission wave and the second transmission wave, and the first reflection wave and the second reflection wave, and the first reflection wave and the second reflection wave. The loopback determination process based on this starts at time t2 and ends at time t5. This is because the folding determination process is performed based on two types of reflected waves, the first reflected wave and the second reflected wave. The signal S4 is turned on for the second time at time t6, and is turned off at time t10 after time t9. In this way, the signal S4 repeats the ON and OFF states at a predetermined cycle (eg, 40 ms cycle) T1 from time t1 to time t6.

<4. FM-CW method for first derivation process>
Next, the processing described with reference to FIG. 3 will be described with reference to FIG. 4 based on the FM-CW (Frequency Modulated Continuous Wave) method. In this embodiment, the FM-CW method will be described as an example. However, the angle of the detection point may be derived by combining a plurality of sections such as a section where the frequency increases and a section where the frequency decreases. For example, it is not limited to the FM-CW method.

FIG. 4 is a diagram illustrating an FM-CW method signal related to the first derivation process. FIG. 4 is a diagram in which the vertical axis represents frequency [unit GHz] and the horizontal axis represents time [unit ms]. The transmission signal TX1 and the transmission signal TX2 in the figure rise from one predetermined frequency (for example, 76.4 GHz) to another predetermined frequency (for example, 76.6 GHz), with the center frequency being f ₀ (for example, 76.5 GHz). Later, a constant change is repeated between 200 MHz so as to decrease from another frequency to one predetermined frequency. That is, a section in which a frequency increases from one predetermined frequency to another predetermined frequency (hereinafter also referred to as “UP section”) and a section in which the frequency decreases from another predetermined frequency to one predetermined frequency (hereinafter referred to as “upper section”). , Also referred to as “DOWN section”).

  The transmission signal TX1 (time t1 to time t2) shown in FIG. 4 is a signal corresponding to the output from the time t1 to the time t2 of the signal S1 with a predetermined period. The transmission signal TX2 (from time t2 to time t3) is a signal corresponding to the output from time t2 to time t3 of the signal S2 with a predetermined period.

  A combination of one UP section and one DOWN section is included twice between time t1 when the first transmission wave having a predetermined cycle is output and time t2 when the output is ended. Therefore, when one UP interval and one DOWN interval are defined as one period of the FM-CW system, frequency modulation for two periods is performed with one output of the first transmission wave. In addition, frequency modulation for two periods is performed by one output of the second transmission wave.

  The reception signal RX (from time t1 to time t4) is a signal corresponding to the output from the time t1 to the time t4 of the signal S3 having a predetermined period. The transmission signal TX3 (time t6) is a signal corresponding to the output from the time t6 of the signal S1 having a predetermined cycle. The reception signal RXa (time t6) is a signal corresponding to the output from the time t6 of the signal S3 having a predetermined period.

  As shown in FIG. 4, the angle, distance, and detection point of the detection point based on the first transmission wave and the second transmission wave and the first reflected wave and the second reflected wave from time t1 to time t5 by the signal processing device 10. Relative speed is derived. That is, for two periods of the first transmission wave and the first reflected wave in the UP section and the DOWN section, and for two periods of the second transmission wave and the second reflected wave in the UP section and the DOWN section (a total of four periods). Based on this, the angle, distance, and relative speed of the detection point are derived. Furthermore, a turn-back determination process is performed between time t2 and time t5 based on the first reflected wave and the second reflected wave.

<5. Time chart for second derivation process>
FIG. 5 is a time chart showing timing related to the second derivation process. As the first derivation process is changed to the second derivation process, the processing timings of the transmission antenna 13a, the transmission antenna 13b, the reception antenna 14, and the signal processing device 10 in the first derivation process shown in FIG. It is changed by a control signal from the changing unit 101.

  The signal S11 in FIG. 5 is a signal having a specific period T2 (80 ms period) in which the predetermined period T1 of the signal S1 is doubled. That is, the first transmission wave is output at a specific period T2 longer than the predetermined period T1.

  The signal S12 is a signal having a specific period T2 in which the predetermined period T1 of the signal S2 is doubled. Here, the signal S12 is turned on at a position substantially in the middle of one cycle of the signal S11. That is, the second transmission wave is output at a substantially intermediate timing (time t6) between one output timing (time t1) of the first transmission wave and the next output timing (time t17).

  The signal S13 is a signal having a predetermined cycle T1 that is the same as the cycle of the signal S3. Here, since the signal S3 receives the first reflected wave and the second reflected wave in one period, the time when the signal S3 is turned on in one period is from time t1 to time t4. On the other hand, since the signal S13 receives the first reflected wave in one cycle and receives the second reflected wave in the next cycle of one cycle, the time during which the signal S13 is in the ON state in one cycle. Is shorter than in the case of the signal S3. Specifically, the signal S13 is turned on from time t1 to time t12 prior to time t4, and is turned off from time t12 to time t6.

  Further, the signal S14 is a signal having the same cycle as that of the signal S4. Here, the signal S4 derives the angle, distance, and relative speed of the detection point based on the first transmission wave and the second transmission wave, and the first reflection wave and the second reflection wave in one period, and is turned back. I do. For this reason, the time for turning on in one cycle is from time t1 to time t5. On the other hand, the signal S14 derives the angle of the detection point based on the first transmission wave and the first reflected wave in one cycle. And the angle of the detection point based on a 2nd transmission wave and a 2nd reflected wave is derived | led-out by the period following one period. For this reason, the time during which the signal S14 is in the ON state in one cycle is shorter than that in the case of the signal S4.

  Specifically, the signal S14 is turned on from time t1 to time t13 before time t5, and is turned off from time t13 to time t6. As a result, the heat generation of the radar apparatus can be suppressed without substantially delaying the object angle derivation process. In addition, although the processing change unit 101 changes the output cycle of the first transmission wave and the second transmission wave to a double cycle, the processing cycle related to the object derivation process does not change, so the processing load on the signal processing device 10 increases. There is nothing. Further, the heat generation of the radar apparatus 1 can be suppressed without substantially reducing the object derivation processing speed of the signal processing apparatus 10.

  Next, the return determination in the signal S14 is performed when the reception antenna 14 receives the first reflected wave and the second reflected wave. In the signal S4 in the first derivation process, the first reflected wave and the second reflected wave are received in the signal processing during one cycle, and therefore the folding determination unit 106 performs the folding determination in one cycle. On the other hand, in the signal S14 in the second derivation process, the first reflected wave is received in one cycle (odd cycle) and the second reflected wave is received in the next cycle (even cycle). For this reason, the return determination unit 106 performs the return determination when the signal S14 is in an ON state during an even period. For example, the loopback determination is performed until the signal S14 is turned on at time t6 and turned off at time t16. Accordingly, the heat generation of the radar apparatus 1 can be suppressed by delaying the timing of the return determination so that the control of the vehicle 19 is hardly affected.

  Hereinafter, the processing timing of each signal will be described in detail. The signal S11 is turned on at time t1, and is turned off at time t2 after time t1. That is, the output of the first transmission wave from the transmission antenna 13a starts at time t1 and ends at time t2. The signal S11 is turned on for the second time at time t17, and is turned off at time t18 after time t17. Thus, the signal S1 repeats the ON and OFF states at a specific period (80 ms period) T2 from time t1 to time t17.

  The signal S12 is turned on at time t6, and is turned off at time t14 after time t6. That is, the output of the second transmission wave from the transmission antenna 13b starts at time t6 and ends at time t14. The signal S12 is turned on for the second time at time t21, and is turned off at time t22 after time t21. Thus, the signal S2 repeats ON and OFF states at a specific period T2 from time t6 to time t21.

  The signal S13 is turned on at time t1, and is turned off at time t12 after time t2. That is, reception of the first reflected wave of the receiving antenna 14 starts at time t1 and ends at time t12. The signal S13 is turned on for the second time at time t6, and is turned off at time t15 after time t14. That is, reception of the second reflected wave of the receiving antenna 14 starts at time t6 and ends at time t15. In this way, the signal S3 repeats ON and OFF at a predetermined period (40 ms period) T1 from time t1 to time t6.

  The signal S14 is turned on at time t1, and is turned off at time t13 after time t12. That is, the angle, distance, and relative speed of the detection point based on the first transmission wave and the first reflected wave are derived between time t1 and time t13. The signal S14 is turned on for the second time at time t6, and is turned off at time t16 after time t15. That is, the angle, distance, and relative speed of the detection point based on the second transmission wave and the second reflected wave are derived between time t6 and time t16. Also, the first reflected wave (received between time t1 and time t12) and the second reflected wave (received between time t6 and time t15) between time t6 and time t16 The return determination process is performed based on the above. In this way, the signal S14 repeats ON and OFF states at a predetermined cycle T1 from time t1 to time t6.

<6. FM-CW method for second derivation process>
Next, the processing described with reference to FIG. 5 will be described with reference to FIG. 6 based on the FM-CW (Frequency Modulated Continuous Wave) method.

  FIG. 6 is a diagram illustrating an FM-CW method signal related to the second derivation process. 6 is different from FIG. 4 described as the diagram showing the signal of the FM-CW policy related to the first derivation process, and the other parts are the drawings showing the same contents. The main difference between FIG. 6 and FIG. 4 is the output timing of the transmission signal.

  The transmission signal TX11 (time t1 to time t2) shown in FIG. 6 is a signal corresponding to the output from the time t1 to the time t2 of the signal S11 having a specific period. The transmission signal TX12 (time t6 to time t14) is a signal corresponding to the output from the time t6 to the time t14 of the signal S12 having a specific period. Here, the time t6 is a time later than the time t2 at which the output of the second transmission wave having the predetermined cycle shown in FIG. 4 is started, and the time t14 is the time of the second transmission wave having the predetermined cycle shown in FIG. This is a time after the time t3 when the output ends. Thus, the transmission signal TX11 and the transmission signal TX12 are not continuously output in time, and after the transmission signal TX11 is output, the transmission unit 13a is switched from the transmission antenna 13a to the transmission antenna 13b, and the predetermined time interval is reached. And a transmission signal TX12 is output.

  The reception signal RX1 (from time t1 to time t12) is a signal corresponding to the output from the time t1 to the time t12 of the signal S13 having a predetermined period. The received signal RX2 (from time t6 to time t15) is a signal corresponding to the output from time t6 to time t15 with a predetermined time interval from the time t12 of the signal S13 having a predetermined period.

  Further, the angle, distance, and relative speed of the detection point are derived by the signal processing device 10 based on the first transmission wave and the first reflected wave having a specific period from time t1 to time t13. That is, the angle, distance, and relative speed of the detection point are derived based on the transmission wave and the reception wave for two periods of the first transmission wave and the first reflected wave in the UP section and the DOWN section.

  In addition, the angle, distance, and relative speed of the detection point are derived based on the second transmission wave and the second reflected wave having a specific period between time t6 and time t16. That is, the angle, distance, and relative speed of the detection point are derived based on the transmission wave and the reception wave for two periods of the second transmission wave and the second reflected wave in the UP section and the DOWN section.

  Note that the first derivation process performed the object detection point derivation process for four periods of the UP section and the DOWN section, whereas the second derivation process performed the detection point for two periods of the UP section and the DOWN section. The derivation process is performed. For this reason, compared with the 1st derivation processing, the accuracy of derivation of the angle etc. of a detection point falls a little.

  However, the first derivation process is switched to the second derivation process when the internal temperature of the radar apparatus 1 is high. The internal temperature of the radar device 1 increases in this way, for example, when the vehicle 19 is stopped. When the vehicle 19 is stopped, a higher detection point derivation accuracy is required as the vehicle travels. is not. For this reason, there is no practical problem even if the accuracy of derivation of detection points by the radar apparatus 1 is slightly reduced by switching from the first derivation process to the second derivation process.

  Furthermore, between the time t6 and the time t16, the first reflected wave (received between the previous time t1 and the time t12) and the second reflected wave (received between the current time t6 and the time t15) and The return determination processing based on is performed.

<7. Processing flowchart>
FIG. 7 is a process flowchart of the signal processing apparatus 10. First, in step S101, it is determined whether or not a predetermined condition for changing the process in the process changing unit 101, that is, whether or not the internal temperature of the radar apparatus is in a predetermined high temperature state. That is, the process changing unit 101 of the signal processing device 10 has at least one sensor information out of sensor information output from the internal temperature sensor 21 of the radar device 1 and the vehicle speed sensor 22 provided in the vehicle 19 to satisfy a predetermined condition. If the condition is satisfied (Yes in step S101), the process proceeds to step S102.

  Here, the sensors that output the sensor information are, for example, the internal temperature sensor 21 and the vehicle speed sensor 22, and the internal temperature sensor 21 directly detects the internal temperature of the radar apparatus, and the vehicle speed sensor 22 is the radar apparatus. The internal temperature of the is detected indirectly. Sensor information of any one of these sensors may be used, or a plurality of them may be combined. The case where the sensor information of the internal temperature sensor 21 satisfies the predetermined condition is, for example, a case where the internal temperature of the radar apparatus 1 exceeds 90 ° C. The case where the sensor information of the vehicle speed sensor 22 satisfies the predetermined condition is, for example, a case where the traveling speed of the vehicle 19 is lower than 20 km / h.

  Here, the reason why the vehicle speed is used to detect the internal temperature of the radar apparatus will be described. While the vehicle is running, the radar device is air-cooled by the air flow, so a large temperature rise does not occur. However, if the vehicle travels at a low speed or stops, the air-cooling effect is lost and the radar device temperature rises. To do. Therefore, it is possible to indirectly detect that the internal temperature of the radar apparatus increases when the vehicle speed is 20 km / h or less, which indicates a low speed state. When the vehicle speed sensor 22 is used for condition determination, the internal temperature of the radar apparatus does not immediately increase even if the vehicle speed becomes low. Therefore, the duration time of 20 km / h or less is also a condition. It is desirable to include. For example, it is desirable to determine that the predetermined condition is satisfied when a state of 20 km / h or less continues for one minute.

  In step S102, the transmission control unit 107 changes the output cycle of the first transmission wave and the second transmission wave from a predetermined cycle to a specific cycle by the control signal of the process changing unit 101, and proceeds to the process of step S103. If the sensor information does not satisfy the predetermined condition (No in step S101), the process proceeds to step S103 without changing the output periods of the first transmission wave and the second transmission wave with the predetermined period.

  In step S103, the transmission antenna 13a outputs the first transmission wave and the transmission antenna 13b outputs the second transmission wave in either the predetermined period or the specific period, and the process proceeds to step S104.

  In step S104, the reception antenna 14 receives at least one of the first reflected wave and the second reflected wave reflected by the object from the first transmission wave and the second transmission wave, and the process proceeds to step S105.

  In step S105, the received signal corresponding to at least one reflected wave of the first reflected wave and the second reflected wave received by the receiving antenna 14 and at least one transmitted wave of the first transmitted wave and the second transmitted wave are supported. The mixer 15 mixes the transmission signal, generates a beat signal that is the difference between the transmission signal and the reception signal, and proceeds to the process of step S106.

  In step S106, the AD converter 16 performs AD conversion on the beat signal, which is an analog signal, converts the beat signal into digital data, and the process proceeds to step S107.

  In step S107 shown in FIG. 8, the Fourier transform unit 102 performs fast Fourier transform processing on the digital data to generate transform data, and the process proceeds to step S108.

  In step S108, the peak extraction unit 103 extracts a peak signal exceeding a predetermined threshold from the signal of the transform data obtained by fast Fourier transform, and the process proceeds to step S109.

  In step S109, the angle of the detection point is calculated based on the eigenvalue of the correlation matrix and the eigenvector, and the process proceeds to step S110.

  In step S110, based on the peak frequency in the conversion data, the distance between the detection point and the vehicle 19 on which the radar apparatus 1 is mounted, and the relative speed between the detection point and the vehicle 19 on which the radar apparatus 1 is mounted are determined as distance / relative speed. The calculation unit 105 calculates and proceeds to the process of step S111.

  Of the processes performed in the signal processing apparatus 10, the processes from step S107 to step S110 are performed as processes corresponding to the first derivation process when the predetermined condition in step S101 is not satisfied (No in step S101). When the predetermined condition in step S101 is satisfied (step S101 is Yes), the process is performed as a process corresponding to the second derivation process.

  In step S111 shown in FIG. 9, when the output period of the first transmission wave and the second transmission wave is changed from the predetermined period to the specific period by the process changing unit 101 (Yes in step S111), the process of step S112 is performed. move on.

  In step S112, when the processing cycle of the signal processing apparatus 10 is an even cycle, that is, when processing for calculating detection point information using a transmission wave and a reception wave by the transmission antenna 13b is performed (step S112 is Yes), the processing in step S113 is performed. The process proceeds to step S115 after the loop determination unit 106 performs the loop determination process. When the processing cycle of the signal processing device 10 is an odd cycle, that is, when processing for calculating detection point information is performed using a transmission wave and a reception wave from the transmission antenna 13a (No in step S112), the loop determination unit 106 performs loopback. The process proceeds to step 115 without making a determination.

  Returning to step S111, if the output period of the first transmission wave and the second transmission wave remains the predetermined period (No in step S111) by the process changing unit 101, the process proceeds to step S114, and the return determination unit 106 determines the return determination. After performing the process, the process proceeds to step S115.

In step S115, the signal processing device 10 outputs detection point information (distance, relative speed, angle) to the vehicle control device 100. Thereby, vehicle control according to the position etc. of the object corresponding to a detection point can be performed.
<8. Angle calculation processing>
Next, angle calculation processing by the angle calculation unit 104 will be described with reference to FIG. FIG. 10 is a diagram illustrating an angular spectrum of detection points related to an object. FIG. 7 is a diagram in which the vertical axis represents the signal level [unit dBv] and the horizontal axis represents the angle [unit deg]. The spectrum US indicates the angle of the detection point in the UP section, and the angle peak Phu1 and the angle peak Phu2 that are signals exceeding the threshold sh are the eigenvalues of the correlation matrix and the angles of the detection points derived from the eigenvectors. Indicates.

  The spectrum DS indicates the angle of the detection point in the DOWN section, and the angle peak Phd1 and the angle peak Phd2 that are signals exceeding the threshold sh are the detection points derived from the eigenvalues and eigenvectors of the correlation matrix. Indicates the angle.

  Next, the angle calculation unit 104 pairs the angle spectrum US in the UP section and the angle spectrum DS in the DOWN section based on the signal level and the angle. The angle calculation unit 104 pairs the angle peaks Phu1 and Phd1 since the signal levels and angles of the angle peaks Phu1 and Phd1 are substantially the same. Further, the angle calculation unit 104 pairs the angle peaks Phu2 and Phd2 because the signal levels and angles of the angle peaks Phu2 and Phd2 are substantially the same.

  As a result, the angle calculation unit 104 derives the average of the two angle peaks by the following equation (3), and calculates the respective angles of the two detection points. Thereby, the angle of the detection point with respect to the vehicle 19 carrying the radar apparatus 1 can be acquired accurately. In the equation, θm represents the angle of the detection point, and θup represents an angle corresponding to the angle peak hu1 (phu2). Θdn represents an angle corresponding to the angle peak Phd1 (Phd2).

＜９．折り返し判定処理＞
次に折り返し判定処理について、図１１、および、図１２を用いて説明する。図１１は第１送信波、および、第２送信波のビームパターンを示す図である。なお、以下においては、図中に示すｘｙ座標軸を用いて、方向を適宜示す。このｘｙ座標軸は車両１９に対して相対的に固定されるものであり、車両１９の車幅方向がｘ軸方向、車両１９の進行方向がｙ方向にそれぞれ対応する。詳細には、車両１９の左方向が−ｘ方向、車両１９の右方向が＋ｘ方向となる。また車両１９が前進する方向が＋ｙ方向、車両１９が後退する方向が−ｙ方向となる。

<9. Return determination processing>
Next, the folding determination process will be described with reference to FIGS. 11 and 12. FIG. 11 is a diagram illustrating beam patterns of the first transmission wave and the second transmission wave. In the following, directions are appropriately indicated using xy coordinate axes shown in the drawing. The xy coordinate axes are fixed relative to the vehicle 19, and the vehicle width direction of the vehicle 19 corresponds to the x-axis direction, and the traveling direction of the vehicle 19 corresponds to the y direction. Specifically, the left direction of the vehicle 19 is the −x direction, and the right direction of the vehicle 19 is the + x direction. The direction in which the vehicle 19 moves forward is the + y direction, and the direction in which the vehicle 19 moves backward is the -y direction.

  A beam pattern BS shown in FIG. 11 is a beam pattern of the first transmission wave output from the transmission antenna 13a. The beam pattern BS has a region (A region) indicated by a symmetric broken line around a central axis CL extending in a straight direction of the vehicle 19 from a substantially center of the vehicle body in the vehicle width direction (x-axis direction) of the vehicle 19.

  The beam pattern BW is the beam pattern of the second transmission wave output from the transmission antenna 13b. Similar to the beam pattern BS, the beam pattern BW has a region indicated by a one-dot chain line symmetrical with respect to the central axis CL. In the region of the beam pattern BW, the region on the right side of the vehicle (+ x direction) other than the region overlapping the A region is defined as the B region, and the region on the vehicle left side (−x direction) other than the region overlapping with the A region is defined as the C region. . Further, the beam pattern BW is a broader beam pattern than the beam pattern BS. The beam pattern is different because the antenna pattern of the transmission antenna 13a is different from the antenna pattern of the transmission antenna 13b.

  FIG. 12 is a diagram showing reception levels in two types of beam patterns. FIG. 12 is a diagram in which the vertical axis represents the signal level [unit dBv] and the horizontal axis represents the angle [unit deg]. Further, the center position of the horizontal axis is 0 degree, the right side is shown as a positive angle, and the left side is shown as a negative angle. Further, it corresponds to each beam pattern region shown in FIG. 11 with ± 5 deg as a boundary. That is, the range from +5 deg to -5 deg corresponds to the A region. An angle range exceeding +5 deg corresponds to the B region. Furthermore, the angle range below −5 deg corresponds to the C region.

  And when a detection point exists in A area | region, when the 1st transmission wave corresponding to beam pattern BS is output, the signal level of a 1st reflected wave is the level shown to the received signal RXS corresponding to A area | region. Become. When the second transmission wave corresponding to the beam pattern BW is output, the signal level of the second reflected wave becomes the level indicated by the reception signal RXW corresponding to the A region, and the signal level of the reception signal RXS is higher than that of the reception signal RXW. Also grows. In this case, the folding determination unit 106 determines that the detection point exists at an angle derived by the angle calculation unit 104 (an angle in the area A).

  Here, the reason why the detection point does not actually exist at one angle although it was derived that the detection point exists at one angle will be described again in detail. For example, when a reflected wave from a detection point is received by a plurality of array antennas, another antenna (hereinafter also referred to as “adjacent antenna”) adjacent to a reference antenna (hereinafter also referred to as “reference antenna”). .) Causes a time difference (phase difference) in the timing of receiving the reflected wave according to the angle at which the detection point exists.

  The vehicle 19 on which the radar apparatus 1 is mounted is directly in front (position on the central axis CL shown in FIG. 11) is 0 degree, the right side (+ x direction) of the vehicle 19 is the + (plus) angle, and the left side (−x direction). Assuming that − is a minus (−) angle, the greater the value of either the plus or minus angle, the greater the phase difference between the reflected waves of adjacent antennas relative to the reference antenna. When the phase difference exceeds 360 degrees, the angle calculation unit 104 exists at the same angle as the angle of the detection point when the phase difference is less than 360 degrees and the angle when the phase difference exceeds 360 degrees. It may be derived as a detection point.

  For example, when the phase difference between the adjacent antennas with respect to the reference antenna is 60 degrees, it is assumed that the angle of the detection point with respect to the vehicle 19 is within the area A shown in FIG. In this case, when the phase difference of the adjacent antenna with respect to the reference antenna is 420 degrees, the angle of the detection point with respect to the vehicle 19 is an angle larger than +5 deg (for example, +30 deg), and exists within the region B shown in FIG. It becomes. However, if the phase exceeds 360 degrees, the phase difference 420 degrees between the adjacent antennas relative to the reference antenna is calculated as the phase difference 60 degrees, and the detection point existing in the B area is derived as existing in the A area. For this reason, although the detection point is derived as existing at the angle of the A region (for example, +5 deg), the detection point does not actually exist at the angle of the A region, but the angle of the B region (for example, +30 deg).

  Returning to the description of FIG. 12, when the detection point exists in the B region, the signal level of the first reflected wave and the signal level of the second reflected wave are the reception signal RXS and the reception signal RXW corresponding to the B region. It becomes the level to show. The signal level of the reception signal RXS is smaller than that of the reception signal RXW. In this case, even if the angle calculation unit 104 derives the angle at which the detection point exists as the angle of the A region, the folding determination unit 106 determines that the detection point is an angle derived by the angle calculation unit 104 (A region angle). Instead, it is determined that the detection point exists at the angle of the B region.

  When the detection point exists in the C region, the signal level of the first reflected wave and the signal level of the second reflected wave are the levels indicated by the reception signal RXS and the reception signal RXW corresponding to the C region. The signal level of the reception signal RXS is smaller than that of the reception signal RXW. In this case, even if the angle calculation unit 104 derives the angle at which the detection point exists as the angle of the A region, the folding determination unit 106 determines that the detection point is an angle derived by the angle calculation unit 104 (an angle within the A region). ), But it is determined that the detection point exists at the angle of the C region. As described above, the folding determination unit 106 determines whether or not a detection point exists at an angle according to the signal level difference between the signal level based on the first reflected wave and the signal level based on the second reflected wave. .

<Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible. Below, such a modification is demonstrated. In addition, all the forms including the form demonstrated in the said embodiment and the form demonstrated below are combinable suitably.

  In the above-described embodiment, the radar apparatus 1 may be used for various purposes other than being mounted on the vehicle 19 (for example, at least one of monitoring of an aircraft in flight and a ship in navigation).

  In the above-described embodiment, the radar apparatus 1 has been described with respect to the electronic scan radar apparatus that includes a plurality of array antennas, electrically fixes the antenna position, and electrically derives the angle of the detection point. In addition, a mechanical scan radar apparatus that derives the angle of the detection point by dynamically changing the position of the antenna may be used.

  In the above embodiment, two transmitting antennas and four receiving antennas are described. However, the number of each antenna may be other than this, for example, three transmitting antennas and five receiving antennas. It may be a book. That is, at least two transmission antennas are sufficient.

  In the above embodiment, the radar apparatus 1 is provided with the reception antenna 14 and the transmission antenna 13 independently, but the reception antenna may also serve as the transmission antenna. In this case, each antenna switches to a reception state immediately after transmitting a transmission wave, and can receive a reflected wave in which the transmission wave is reflected by an object.

  In the above-described embodiment, the radar apparatus 1 may be provided with a dedicated processing circuit (mixer 15 and AD converter 16) for each reception antenna 14, but collectively processes the reception signals from all reception antennas. A circuit may be provided. In this case, it is necessary to control the reception antenna 14 corresponding to the processing circuit in a time-sharing manner from the reception antennas 14a to 14d in sequence, but the circuit configuration of the radar apparatus 1 can be made compact.

  In the above embodiment, the beam pattern BS of the first transmission wave and the beam pattern BW of the second transmission wave have been described. However, if the shape of each beam pattern is different, the beam pattern of each transmission antenna is Other than the beam pattern described in the embodiment. In other words, the antenna pattern of the antenna may be an antenna pattern other than the antenna pattern corresponding to the beam pattern of the above embodiment.

  In the above embodiment, the period of the signals S11 and S12 related to the second derivation process described with reference to FIG. 5 is the period T2 (80 ms period) that is twice the predetermined period T1, but the period T2 is 80 ms. Other periods may be used. In other words, it may be a period longer than the predetermined period T1 in a period other than twice the predetermined period T1. Furthermore, although the cycle of the signal S13 is the predetermined cycle T1 (40 ms), it may be a cycle other than 40 ms. In this case, the length of the cycle of the signal S13 may be adjusted according to the cycle of the signal S11 and the signal S12. Further, although the cycle of the signal S14 is set to the predetermined cycle T1 (40 ms), it may be a cycle other than 40 ms. In this case, the length of the cycle of the signal S14 may be adjusted according to the cycle of the signal S11 and the signal S12.

  Moreover, in the said embodiment, as an example which changes the output timing of the transmission wave of the transmission antenna 13b which outputs a 2nd transmission wave into another output timing, the output timing of one 1st transmission wave from the transmission antenna 13a, It has been described that the control signal that is changed so as to be transmitted at a timing substantially in the middle of the timing at which the next first transmission wave is output is output to the transmission control unit 107. In addition to this, if it is between the output timing of one first transmission wave from the transmission antenna 13a and the timing at which the next first transmission wave is output, the output timing of one first transmission wave and the next first The second transmission wave may be output at a timing other than substantially the middle of the timing at which the transmission wave is output.

  In the above embodiment, as the predetermined condition for changing the output cycle of the first transmission wave and the second transmission wave, at least one sensor information of the internal temperature sensor 21 and the vehicle speed sensor 22 satisfies the predetermined condition. As described above, other sensors may be used as long as the internal temperature of the radar apparatus can be estimated. For example, as a predetermined condition other than this, an outside air temperature detected by a temperature sensor provided in the vehicle 19 may be used as a condition. In this case, for example, when the outside air temperature detected by the temperature sensor exceeds 30 degrees, the predetermined condition of the process changing unit 101 may be satisfied.

  Furthermore, the process change unit 101 may determine whether or not the predetermined condition is satisfied using information obtained from the vehicle 19 and the device provided in the vehicle 19. For example, even if the process change unit 101 determines based on any one of the conditions such as the time zone in which the vehicle 19 travels, the weather, the output information from the navigation device mounted on the vehicle 19, and the lighting state of the light of the vehicle 19. Good.

  The judgment of whether or not the predetermined condition is satisfied with respect to the time zone is good because the outside temperature is brighter in the daytime than in the nighttime, so the driver's visibility is good. Therefore, it is estimated that the internal temperature of the radar device 1 is high during the daytime, and the output period of the first transmission wave and the second transmission wave is set as a specific period, and the detection point may be derived in the second derivation process. . On the other hand, the visibility of the driver's field of view is worse than in the daytime because the outside air temperature is low and dark at night. Therefore, at night, the internal temperature of the radar apparatus 1 does not increase as much as in the daytime, so that the output period of the first transmission wave and the second transmission wave may be set to a predetermined period, and the detection point may be derived by the first derivation process.

  In addition, since the driver's line of sight becomes worse at night, the detection point may be derived by the first derivation process by prohibiting switching to the second derivation process so as not to reduce the object detection accuracy.

  In addition, in the case of rainy or snowy weather, the judgment of whether or not the predetermined condition is met with respect to the weather also deteriorates the visibility of the driver's field of view, so the output of the first transmission wave and the second transmission wave The detection point may be derived by the first derivation process with the period being a predetermined period. In other words, in the case of rainy or snowy weather, the driver's view is also poor, so switching to the second derivation process is prohibited so as not to reduce the object detection accuracy, and the detection point is determined by the first derivation process. It may be derived.

DESCRIPTION OF SYMBOLS 1 ... Radar apparatus 10 ... Signal processing apparatus 11 ... Signal generation part 12 ... Oscillator 13 ... Transmission antenna 14 ... Reception antenna 15 ... Mixer 16 .... AD converter

Claims (4)

A radar device for deriving at least an angle of a detection point related to an object,
First transmission means for outputting a first transmission wave at a predetermined period;
Second transmission means for outputting the second transmission wave at a timing different from the timing of outputting the first transmission wave at the predetermined period;
Receiving means for receiving a first reflected wave reflected from the detection point by the first transmission wave and a second reflected wave reflected from the detection point by the second transmission wave;
Derivation means for performing a first derivation process for deriving an angle of the detection point based on the first transmission wave and the second transmission wave, and the first reflected wave and the second reflected wave;
With
The first transmission means outputs the first transmission wave at a specific period that is longer than the predetermined period when a predetermined condition is satisfied,
The second transmission means outputs the second transmission wave at the specific period when the predetermined condition is satisfied, and outputs the output timing and the next output of the first transmission wave transmitted at the specific period. Outputting the second transmission wave at a timing substantially in the middle of the timing;
The derivation means derives an angle of the detection point based on the first transmission wave and the first reflected wave instead of the first derivation process when the predetermined condition is satisfied, and the second Performing a second derivation process for deriving an angle of the detection point based on a transmitted wave and the second reflected wave;
A radar device characterized by the above. The radar apparatus according to claim 1, wherein
The specific period is twice the predetermined period;
A radar device characterized by the above. The radar apparatus according to claim 1 or 2,
The beam pattern of the first transmission wave is a beam pattern different from the beam pattern of the second transmission wave,
The derivation means performs a loopback determination for determining whether or not the detection point exists at the angle according to a signal level difference between the signal level of the first reflected wave and the signal level of the second reflected wave. When the first derivation process is performed, the return determination is performed based on the first reflected wave and the second reflected wave received by the receiving means within the predetermined period, and the second When performing the derivation process, performing the return determination based on the first reflected wave and the second reflected wave received by the receiving means within the specific period;
A radar device characterized by the above. An object derivation method for deriving at least an angle of a detection point related to an object,
(A) outputting a first transmission wave at a predetermined period;
(B) outputting the second transmission wave at a timing different from the timing of outputting the first transmission wave at the predetermined period;
(C) receiving a first reflected wave reflected from the detection point by the first transmission wave and a second reflected wave reflected from the detection point by the second transmission wave;
(D) performing a first derivation process for deriving an angle of the detection point based on the first transmission wave and the second transmission wave, and the first reflected wave and the second reflected wave;
With
In the step (a), when a predetermined condition is satisfied, the first transmission wave is output at a specific period that is longer than the predetermined period.
In the step (b), when the predetermined condition is satisfied, the second transmission wave is output in the specific period, and one transmission timing and the next transmission of the first transmission wave transmitted in the specific period Outputting the second transmission wave at a timing substantially in the middle of the timing;
The step (d) derives the angle of the detection point based on the first transmission wave and the first reflected wave instead of the first derivation process when the predetermined condition is satisfied, and Performing a second derivation process for deriving an angle of the detection point based on a second transmission wave and the second reflected wave;
An object derivation method characterized by

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