JP2011137779A - Object detecting apparatus and object detection program - Google Patents

Object detecting apparatus and object detection program Download PDF

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JP2011137779A
JP2011137779A JP2010000075A JP2010000075A JP2011137779A JP 2011137779 A JP2011137779 A JP 2011137779A JP 2010000075 A JP2010000075 A JP 2010000075A JP 2010000075 A JP2010000075 A JP 2010000075A JP 2011137779 A JP2011137779 A JP 2011137779A
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frequency
distance
beat frequency
transmission
unit
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JP5402647B2 (en
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Kazusuke Hamada
和亮 浜田
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Fujitsu Ltd
富士通株式会社
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an object detector for periodically outputting a detected result obtained by utilizing an FM-CW radar. <P>SOLUTION: The object detector includes a registering part for registering distance data showing a distance determined, according to an UP/DOWN frequency having a difference smaller than a threshold frequency; a pair generating part for pairing the UP/DOWN frequency, if the distance data having a difference from the distance smaller than a threshold distance is already registered, when the difference of the UP/DOWN frequency is smaller than the threshold frequency; a transmission control part for instructing a transmitting wave to be transmitted at intervals of first time and instructing to the transmitting wave to be transmitted at intervals of second time, if the distance data having the difference from the distance smaller than the threshold distance is not registered, when the difference of the UP/DOWN frequency is smaller than the threshold frequency and an output part for outputting a pairing result at intervals of first time. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an object detection apparatus, an object detection method, and an object detection program that detect an object using FM-CW radar.

  Conventionally, an object detection device (hereinafter sometimes referred to as an FM-CW radar device) that detects a distance to a moving object such as a vehicle and its speed using FM-CW (Frequency Modulated Continuous Wave) is practical. It has become. The FM-CW radar device transmits frequency-modulated radio waves (for example, millimeter waves). Then, by detecting the frequency difference between the frequency of the transmitted radio wave and the frequency of the reflected wave reflected back from the object, the distance to the stationary object / moving object and the speed of the moving object are calculated.

FIG. 1 is a diagram for explaining the operation of the FM-CW radar apparatus. In FIG. 1, fs (t) represents the frequency of a radio wave (transmission wave) transmitted from the FM-CW radar apparatus. Thus, the transmission wave has a section in which the frequency increases linearly (UP section) and a section in which the frequency decreases linearly (DOWN section). “F 0 ” represents the center frequency of the transmission wave, “T” represents the modulation period of the transmission wave, and “β” represents the frequency modulation band of the transmission wave.

The FM-CW radar apparatus receives a reflected wave from a target within the radar range. In FIG. 1, fr (t) represents the frequency of the reflected radio wave (reflected wave or received wave). The received wave is delayed by time τ with respect to the transmitted wave according to the distance between the FM-CW radar apparatus and the target. The frequencies of the transmission wave and the reception wave have the following characteristics.
(A) A received wave at a certain time is a reflected wave of a transmission wave generated a time τ before that time. Therefore, in the UP section, the frequency of the received wave is lower than the current transmission frequency. In the DOWN section, the frequency of the received wave is higher than the current transmission frequency.
(B) The frequency of the received wave obtained by the target approaching the FM-CW radar apparatus increases according to the speed of the target due to the Doppler effect. In addition, the frequency of the received wave obtained by the target moving away from the FM-CW radar apparatus is lowered according to the speed of the target due to the Doppler effect.

  The FM-CW radar device generates a beat signal by mixing a transmission wave and a reception wave, and detects a beat frequency. The beat frequency corresponds to the difference between the transmission wave frequency fs (t) and the reception wave frequency fr (t). At this time, a beat frequency fup (hereinafter referred to as UP frequency) is detected in the UP section, and a beat frequency fdown (hereinafter referred to as DOWN frequency) is detected in the DOWN section. In the example illustrated in FIG. 1, the FM-CW radar apparatus receives a reflected wave from a target approaching the FM-CW radar apparatus. For this reason, the DOWN frequency fdown is higher than the UP frequency fup. When the target moves away from the FM-CW radar apparatus, the DOWN frequency fdown is lower than the UP frequency fup. In addition, when the target is stationary, the UP frequency fup and the DOWN frequency fdown substantially coincide with each other.

  FIG. 2 is a diagram illustrating a spectrum of a beat signal obtained from one target. When the target is stationary, the UP frequency fup and the DOWN frequency fdown coincide with each other as shown in FIG. In this case, the distance from the FM-CW radar apparatus to the target is calculated based on the sum or average (= f1) of fup and fdown.

  When the target approaches the FM-CW radar apparatus, the DOWN frequency fdown is higher than the UP frequency fup, as shown in FIG. When the target moves away from the FM-CW radar apparatus, the DOWN frequency fdown is lower than the UP frequency fup as shown in FIG. In these cases, the distance from the FM-CW radar device to the target is calculated based on the sum or average of fup and fdown. The target speed is calculated based on the difference between fup and fdown.

  Note that the difference between fup and fdown is caused by the Doppler effect resulting from the movement of the target. Therefore, in the following description, the difference between fup and fdown may be referred to as “Doppler displacement”. That is, when the speed of the target is high, the Doppler displacement is large, and when the Doppler displacement is zero, it is determined that the target is stationary.

  FIG. 3 is a diagram for explaining a method of detecting a plurality of targets by the FM-CW radar apparatus. Here, it is assumed that UP frequencies 1 and 2 are detected in the UP section and DOWN frequencies 1 and 2 are detected in the DOWN section as beat frequencies. Further, it is assumed that the UP frequency 2 and the DOWN frequency 1 are substantially the same. Further, in the example shown in FIG. 3A, beat signals are generated by the stationary object A and the moving object B, and in the example shown in FIG. 3B, beat signals are generated by the two moving objects B1 and B2. Shall.

  When an object existing in the radar range is detected, pairing of the UP frequency and the DOWN frequency is performed. Then, a corresponding object is detected based on each frequency pair. That is, for example, the distance to the target is calculated based on the sum of the paired UP frequency and the DOWN frequency, and the target speed is calculated based on the difference between the paired UP frequency and the DOWN frequency. “Pairing” is a process for determining a pair of an UP frequency and a DOWN frequency.

  Here, the set of UP frequency and DOWN frequency obtained by the stationary object substantially coincide with each other. That is, the Doppler displacement caused by the stationary object is almost zero. Therefore, in the example shown in FIG. 3, the UP frequency 2 and the DOWN frequency 1 are first paired. In this case, it is assumed that the UP frequency 2 and the DOWN frequency 1 are obtained by the stationary object, and the distance to the stationary object is calculated based on the frequency f2. Subsequently, the remaining beat signals (that is, UP frequency 1 and DOWN frequency 2) are paired. Then, assuming that the UP frequency 1 and the DOWN frequency 2 are obtained by the moving object, the distance to the stationary object and the speed of the moving object are calculated based on the frequencies f1 and f3. Thereby, in the example shown to Fig.3 (a), the stationary object A and the moving object B are detected correctly.

  However, in the example shown in FIG. 3B, the above algorithm makes the pairing of the UP frequency and the DOWN frequency inappropriate. That is, in practice, UP frequency 1 and DOWN frequency 1 are generated by moving object B1, and UP frequency 2 and DOWN frequency 2 are generated by moving object B2, but the Doppler displacement is zero. 2 and DOWN frequency 1 are paired first, and the remaining UP frequency 1 and DOWN frequency 2 are paired. As a result, the distance to the moving objects B1 and B2 and the speed of the moving objects B1 and B2 may not be detected correctly.

As a related technique, an object detection apparatus including a transmission unit, a mixer, a frequency calculation unit, and a stationary object frequency detection unit has been proposed. The transmission / reception means receives a reflected wave from an object by transmitting a transmission wave having a frequency increase section in which the frequency increases and a frequency decrease section in which the frequency decreases. The mixer generates a beat signal by mixing the transmitted wave and the reflected wave. The frequency calculation means calculates the frequency component of the beat signal in the frequency increase interval and the frequency decrease interval. The stationary object frequency detection means has a frequency component level in one of the frequency increase section and the frequency decrease section that exceeds a high threshold, and the level of the same frequency component in the other section exceeds a low threshold that is less than the high threshold, and If the level difference between the two is within a predetermined range, it is detected as a frequency component of a stationary object. (For example, Patent Document 1)
As other related techniques, the following on-vehicle radar devices have been proposed. This radar device has continuity determination means for determining the continuity between the detected past target data and the current target data under the conditions of the distance difference from the target, the relative speed difference, and the lateral position difference. Have. When the continuity determination means determines the continuity of the target, whether the previous and current targets satisfy the lateral position difference in addition to the determination conditions for the distance difference from the target and the relative speed difference. Alternatively, continuity is determined from the condition that satisfies the angle difference. (For example, Patent Document 2)

JP 2008-1111779 A JP 2004-132734 A

As described above, in the conventional detection method, a stationary object and a moving object may not be detected correctly.
In addition, a radar device that captures a target using past target data and current target data has been proposed. However, in the proposed configuration, a stationary object and a moving object are mixed in the radar range. In some cases, the detection result cannot be output periodically. If the detection result is not output regularly, for example, the process of calculating the trajectory of the moving object or estimating the moving direction becomes complicated.

  The subject of this invention is providing the object detection apparatus which outputs periodically the detection result obtained using FM-CW radar.

  An object detection apparatus according to one aspect of the present invention includes a transmission unit that transmits a transmission wave including a frequency increase period and a frequency decrease period, and a beat that generates a beat signal of the transmission wave and a reflected wave corresponding to the transmission wave. A signal generating unit; a storage unit for storing frequency information related to an ascending interval beat frequency detected during the frequency increasing interval and a descending interval beat frequency detected during the frequency decreasing interval; a first ascending interval beat frequency; When the difference from one falling section beat frequency is smaller than a threshold frequency, the frequency information represents a first distance determined based on the first rising section beat frequency and the first falling section beat frequency. The difference between the registration unit that registers the distance data in the storage unit and the first rising section beat frequency and the first falling section beat frequency is the threshold frequency. When distance data whose difference from the first distance is smaller than a threshold distance when it is smaller than the number is already registered in the storage unit, the first rising section beat frequency and the first falling A pair generation unit for pairing with a section beat frequency, and instructing the transmission unit to transmit the transmission wave at a first time interval, and the first rising section beat frequency and the first falling section beat frequency If the distance data whose difference from the first distance is smaller than the threshold distance is not registered in the storage unit when the difference from the threshold frequency is smaller than the threshold frequency, than the first time interval A transmission control unit that instructs the transmission unit to transmit the transmission wave at a short second time interval; and an output unit that outputs a pairing result by the pair generation unit at the first time interval.

  According to the configuration disclosed in the present application, it is possible to periodically output a detection result obtained using the FM-CW radar.

It is a figure explaining operation | movement of an FM-CW radar apparatus. It is a figure which shows the spectrum of the beat signal obtained from one target. It is a figure explaining the method to detect a some target. It is a figure which shows the structure of the object detection apparatus of embodiment. It is a block diagram explaining the function of the object detection apparatus of embodiment. It is a figure explaining the transmission control by a transmission control part. It is a figure which shows the spectrum of a beat signal. It is a figure explaining the method to detect a stationary object from UP / DOWN frequency. It is a figure which shows the spectrum of the beat frequency obtained in the operation example 1. FIG. It is a figure which shows the example of the data stored in a memory | storage part in the operation example 1. FIG. It is a figure which shows the spectrum of the beat frequency obtained in the operation example 2. It is a flowchart which shows schematic operation | movement of the object detection apparatus of embodiment. It is a flowchart which shows a pairing process. It is a figure explaining the pairing by auxiliary measurement. It is a figure which shows the hardware constitutions of the control part of an object detection apparatus.

  FIG. 4 is a diagram illustrating a configuration of the object detection device according to the embodiment. The object detection device 1 according to the embodiment includes an IF unit 11, a control unit 12, an oscillator 13, filters 14, 23 and 26, amplifiers 15, 19, 21, 24 and 27, switches 16 and 20, a directional coupler 17, and an antenna. 18, a mixer 22, an analog signal processing unit 25, and an A / D converter 28.

  The IF unit 11 provides an interface between the object detection device 1 and a host device. That is, the IF unit 11 notifies the control unit 12 of an instruction from the host device, and notifies the host device of the processing result by the control unit 12. The host device is a computer having a CPU. Further, the host device uses the processing result output from the object detection device 1 to perform, for example, the calculation of the locus of the detected moving object or the estimation of the moving direction. Further, the host device may control the overall operation of the object detection device 1.

  The oscillator 13 outputs a transmission wave (measurement signal) according to control by the control unit 12. The transmission wave is a frequency-modulated signal, and has a frequency rising section (hereinafter, referred to as an UP section) in which the frequency increases linearly and a frequency falling section (hereinafter, referred to as a DOWN section) in which the frequency decreases linearly. May be included). The oscillator 13 is, for example, a voltage controlled oscillator and oscillates at a frequency corresponding to the control voltage supplied from the control unit 12.

  An unnecessary frequency component is removed from the transmission wave output from the oscillator 13 by the filter 14. That is, the filter 14 filters the frequency so that only a transmission wave having a necessary frequency component is wirelessly transmitted via the antenna 18. The amplifier 15 amplifies the transmission wave output from the filter 14. The switch 16 outputs the transmission wave amplified by the amplifier 15 to the directional coupler 17 when being controlled to be in the ON state. The switch 16 is controlled by the control unit 12, for example. The directional coupler 17 guides the transmission wave output from the switch 16 to the antenna 18 and guides the reflected wave input via the antenna 18 to the amplifier 19.

  The antenna 18 wirelessly transmits a transmission wave output from the directional coupler 17 in a predetermined direction, and receives a reflected wave corresponding to the transmission wave. The amplifier 19 amplifies the reflected wave output from the directional coupler 17. When the switch 20 is controlled to be turned on, the switch 20 outputs the reflected wave amplified by the amplifier 19 to the mixer 22. The switch 20 is controlled by the control unit 12, for example.

  The amplifier 21 amplifies the transmission wave output from the filter 14. The mixer 22 mixes the transmission wave amplified by the amplifier 21 and the reflected wave amplified by the amplifier 19 to generate a beat signal. In other words, the mixer 22 generates a beat signal of the transmission wave and the reflected wave. The frequency of the beat signal corresponds to the difference between the frequency of the transmitted wave and the frequency of the reflected wave.

  The filter 23 removes noise included in the beat signal. The amplifier 24 amplifies the beat signal output from the filter 23. The analog signal processing unit 25 includes, for example, a hold circuit and an integration circuit, and shapes the beat signal into a continuous waveform. The reflected wave may become a waveform that is shredded by switching of the switch 20.

  The filter 26 removes unnecessary signals from the beat signal included in the output of the analog signal processing unit 25. The amplifier 27 amplifies the beat signal output from the filter 26. The A / D converter 28 converts the beat signal into a digital signal and outputs it to the control unit 12.

  The control unit 12 includes a digital signal processing unit (DSP), for example, and executes object detection processing using a digital signal representing a beat signal. That is, the control unit 12 calculates the frequency component of each beat signal, for example, by FFT. Subsequently, the control unit 12 may sometimes be referred to as a beat frequency component detected in the UP section (hereinafter may be referred to as UP frequency) and a beat frequency component detected in the DOWN section (hereinafter referred to as DOWN frequency). )). Then, the control unit 12 calculates the distance from the object detection device 1 to the target (stationary object, moving object) and the speed of the moving object based on the paired UP frequency and DOWN frequency.

  FIG. 5 is a block diagram illustrating functions of the object detection device 1 according to the embodiment. The object detection apparatus 1 according to the embodiment includes a transmission unit 31, a beat signal generation unit 32, a storage unit 33, a registration unit 34, a pair generation unit 35, a transmission control unit 36, and an output 37. The registration unit 34, the pair generation unit 35, the transmission control unit 36, and the output 37 are realized by the control unit 12. The storage unit 33 may be provided inside the control unit 12 or may be provided outside the control unit 12.

  The transmission unit 31 includes the oscillator 13 illustrated in FIG. 4, and generates a transmission wave including an UP section (frequency information section) and a DOWN section (frequency decrease section) in accordance with an instruction from the transmission control unit 36. This transmission wave is generated, for example, by modulating the frequency of a continuous wave (CW) so as to have an UP section and a DOWN section shown in FIG. Here, when a transmission instruction is given from the transmission control unit 36, the transmission unit 31 generates, for example, a transmission wave having a set of UP sections and DOWN sections. In the following description, a transmission wave having a set of UP section and DOWN section may be referred to as a “measurement signal”. That is, each time a transmission instruction is given from the transmission control unit 36, the transmission unit 31 generates one measurement signal. In this example, the speed at which the frequency increases in the UP section and the speed at which the frequency decreases in the DOWN section are the same. In each measurement signal, a DOWN section may be provided after the UP section, or a DOWN section may be provided before the UP section.

  The beat signal generation unit 32 includes the mixer 22 and the A / D converter 28 shown in FIG. 4 and generates a beat signal of a transmission wave and a reflected wave corresponding to the transmission wave. At this time, logically, one beat signal is generated for one target. The generated beat signal is represented by digital data and transmitted to the control unit 12. Here, the frequency of the beat signal (beat frequency) corresponds to the difference between the frequency of the transmitted wave and the frequency of the corresponding reflected wave. In the following description, the frequency of the beat signal generated in the UP section may be referred to as “UP frequency”, and the frequency of the beat signal generated in the DOWN section may be referred to as “DOWN frequency”. That is, logically, one set of UP frequency and DOWN frequency is detected for one target.

  The storage unit 33 stores frequency information related to the UP frequency detected in the UP section and the DOWN frequency detected in the DOWN section. The storage unit 33 is realized by a memory region included in the control unit 12 or a memory region connected to the control unit 12.

  The registration unit 34 searches for a combination of an UP frequency and a DOWN frequency in which the Doppler displacement (that is, the difference between the UP frequency and the DOWN frequency) is smaller than the threshold frequency. When a combination of an UP frequency and a DOWN frequency satisfying this condition is detected, the registration unit 34 obtains distance data representing a distance determined based on the detected UP frequency and DOWN frequency as the frequency information described above. Register in the temporary registration table in the storage unit 33. Here, when the target is stationary, as described with reference to FIG. 2, the set of UP frequency and DOWN frequency corresponding to the target substantially coincide with each other. In addition, a sufficiently small value for determining whether or not the target corresponding to one set of UP frequency and DOWN frequency is stationary is used as the threshold frequency. Then, when it is determined that the target corresponding to one set of UP frequency and DOWN frequency is stationary, the registration unit 34 displays distance data representing a distance determined based on the one set of UP frequency and DOWN frequency. Register in the temporary registration table. The distance data is represented by, for example, the sum of a set of UP frequency and DOWN frequency.

  The pair generation unit 35 checks whether the same or almost the same distance data as the distance data corresponding to the UP frequency and the DOWN frequency newly detected by the registration unit 34 is already registered in the temporary registration table. At this time, distance data whose difference from the newly obtained distance data is smaller than a predetermined threshold distance is searched in the temporary registration table. If the new distance data is approximately the same as the distance data registered in the temporary registration table in the past, the pair generation unit 35 determines that the target exists at the same position in the past and the present. That is, it is determined that the target is stationary. Further, the pair generation unit 35 determines that the UP frequency and the DOWN frequency are generated by the reflected wave from the stationary object, and pairs the UP frequency and the DOWN frequency.

  In general, a plurality of UP frequencies are detected in the UP section, and a plurality of DOWN frequencies are detected in the DOWN section. In this case, the pair generation unit 35 first determines a pair of UP frequency and DOWN frequency corresponding to a stationary object, and then corresponds to another target (mainly a moving object) from the remaining frequency components. A pair of UP frequency and DOWN frequency is determined.

  The transmission control unit 36 instructs the transmission unit 31 to transmit a transmission wave (one measurement signal) at a basic transmission interval. Also, distance data in which the difference between the detected UP frequency and the DOWN frequency is smaller than the threshold frequency and the difference between the UP frequency and the distance corresponding to the DOWN frequency is smaller than the threshold distance is temporarily registered. If not registered in the table, the transmission control unit 36 instructs the transmission unit 31 to transmit a transmission wave at a time interval shorter than the basic transmission interval.

  FIG. 6 is a diagram for explaining transmission control by the transmission control unit 36. As shown in FIG. 6A, the transmission control unit 36 causes the transmission unit 31 to output a measurement signal at a constant time interval (for example, an interval of 100 milliseconds (basic transmission interval or first time interval)). In this example, measurement signals 1, 2, 3, and 4 are transmitted at times 1, 2, 3, and 4, respectively. Each measurement signal includes an UP section and a DOWN section shown in FIG. The period of the measurement signal (the sum of the UP section and the DOWN section included in the measurement signal) is sufficiently short with respect to the basic transmission interval, for example, about 1 to 10 milliseconds.

  However, when an UP frequency and a DOWN frequency whose difference is smaller than the threshold frequency are detected for one measurement signal transmitted at the basic transmission interval, the transmission control unit 36 determines that the newly detected UP It is checked whether or not distance data whose difference from the distance data corresponding to the / DOWN frequency is smaller than the above threshold distance is registered in the temporary registration table. When distance data whose difference from the new distance data is smaller than the above threshold distance is not registered in the temporary registration table, the transmission control unit 36, as shown in FIG. In addition to the measurement signal transmitted in step 1, the transmitter 31 is caused to transmit one or more measurement signals in order to perform auxiliary measurement. For example, when the beat frequency based on the measurement signal 1 transmitted at time 1 is measured and the distance data satisfying the above-mentioned conditions is not registered in the temporary registration table, the transmission control unit 36 is prior to time 2. In addition, the transmitter 31 is caused to additionally transmit a measurement signal. In the example shown in FIG. 6B, the measurement signal 1a is transmitted at time 1a between time 1 and time 2. The time interval (second time interval) from time 1 to time 1a is set to be longer than the total processing time of the registration unit 34, pair generation unit 35, output unit 37, and calculation unit 38, for example.

  The output unit 37 outputs the result of pairing by the pair generation unit 35 at the basic transmission interval. In the example shown in FIG. 6A, for example, times 1, 2, 3,. . . The pairing results obtained by using the measurement signal transmitted to the time are respectively times 2, 3, 4,. . . Is output. In the example shown in FIG. 6B, the pairing result obtained according to the measurement signals 1 and 1a is output at time 2, and the pairing result obtained according to the measurement signal 2 is output at time 3. Yes. That is, the output unit 37 outputs the result of pairing by the pair generation unit 35 at the basic transmission interval regardless of whether or not the measurement signal is transmitted at the basic transmission interval.

  The calculation unit 38 calculates the distance from the object detection device 1 to the target based on the UP frequency and the DOWN frequency paired by the pair generation unit 35. Further, the calculation unit 38 may calculate the distance from the object detection device 1 to the target and the speed of the target based on the paired UP frequency and DOWN frequency. The calculation result by the calculation unit 38 may be output together with the result of pairing by the pair generation unit 35, for example. Further, the calculation unit 38 may be realized by a host device connected via the IF unit 11.

When the transmission wave shown in FIG. 1 is transmitted as a measurement signal, beat frequencies (UP frequency fup, DOWN frequency fdown) generated according to the reflected wave from the target are expressed by the following equations.
fup = (4β / T) × r + (2f 0 / c) × V
fdown = (4β / T) × r− (2f 0 / c) × V
“R” represents the distance from the object detection apparatus 1 to the target. “V” represents the velocity of the target. “C” represents the speed of light. “Β” represents the frequency modulation band of the measurement signal (transmission wave). “T” represents the modulation period of the measurement signal. “F 0 ” represents the center frequency of the measurement signal (transmission wave).

Therefore, when the UP frequency and the DOWN frequency are paired for each target, and the simultaneous equations are solved for each pair, the distance r is calculated for each target by the following equation (1), and each target is calculated by the following equation (2). A speed V is calculated.
r = (fup + fdown) × T / (8β) (1)
V = (fup−fdown) × c / (4f 0 ) (2)

  Thus, in the object detection method of the embodiment, when an UP / DOWN frequency that is considered to be caused by a stationary object is detected, distance data corresponding to the UP / DOWN frequency is registered in the temporary registration table. At this time, if substantially the same distance data is already registered in the temporary registration table, it is determined that the UP / DOWN frequency is likely to be obtained by a stationary object, and pairing of the UP / DOWN frequency is performed. determine.

  On the other hand, if substantially the same distance data is not registered in the temporary registration table, it is determined whether or not the UP / DOWN frequency is obtained by a stationary object, and the next measurement signal in the basic transmission interval is determined. In addition, one or more measurement signals are transmitted before. Then, using this additional measurement signal, before the next measurement signal in the basic transmission interval, it is determined whether the UP / DOWN frequency is obtained by a stationary object, and the UP / DOWN frequency is determined. Perform pairing. Even in this case, the pairing result is output in synchronization with the basic transmission interval. That is, according to the method of the embodiment, pairing information with high accuracy for a stationary object is output at regular time intervals.

  Next, the operation of the object detection device 1 according to the embodiment will be described in detail. The object detection device 1 periodically transmits a measurement signal in a predetermined direction. As shown in FIG. 1, the measurement signal includes an UP section and a DOWN section. A transmission wave whose frequency rises linearly is transmitted in the UP interval, and a transmission wave whose frequency decreases linearly is transmitted in the DOWN interval. And the object detection apparatus 1 receives the reflected wave from a target, and produces | generates the beat signal of a transmission wave and a reflected wave in each of an UP area and a DOWN area. Thereby, for each measurement signal, the UP frequency is detected in the UP section, and the DOWN frequency is detected in the DOWN section.

  When there are a plurality of targets in the radar range, the object detection device 1 receives a plurality of reflected waves. In this case, a plurality of beat signals are generated in each of the UP section and the DOWN section.

  When there are a plurality of targets in the radar range, as shown in FIG. 7, a plurality of frequency components are detected as the spectrum of the beat signal. At this time, the reflected wave received by the object detection device 1 includes noise. For this reason, the object detection apparatus 1 extracts only frequency components exceeding a predetermined threshold level as frequency components of beat signals used for object detection. The frequency component is extracted in each of the UP section and the DOWN section.

  FIG. 8 is a diagram for explaining a method of detecting a stationary object from the UP frequency and the DOWN frequency. FIG. 8 shows the spectrum of the beat signal obtained in the UP section and the DOWN section.

  When the target is stationary, the UP frequency and DOWN frequency obtained from the target are substantially the same. Further, the levels of beat signals obtained from one target in the UP section and the DOWN section are substantially the same. Therefore, the object detection apparatus 1 extracts the UP frequency and the DOWN frequency whose frequencies substantially coincide with each other as the frequency component pair caused by the stationary object. In FIG. 8, two sets of frequency components are detected. In addition, it is preferable that the frequency components extracted as a pair have the same or almost the same level.

  Subsequently, the object detection device 1 performs pairing of frequency components that are considered to be caused by the same target by various conventional algorithms except for the frequency components in the stationary object, and moves based on each pair. Detect an object.

  As described above, the object detection apparatus 1 performs pairing of the UP frequency and the DOWN frequency caused by the stationary object, and performs pairing of the UP frequency and the DOWN frequency caused by the moving object in the remaining frequency components. For this reason, if the stationary object is detected incorrectly, the moving object cannot be detected correctly. Therefore, the object detection device 1 of the embodiment performs a plurality of measurements in order to detect a stationary object.

<Operation example 1>
FIG. 9 is a diagram showing the spectrum of the beat frequency obtained in the first operation example. In FIG. 9, the spectrum of the UP section and the DOWN section obtained from time 1 to time 4 is shown. In this example, two frequency components are obtained in the UP section and DOWN section at each time. In the following description, the two frequency components obtained in the UP section are referred to as f (u1) and f (u2) in order from the smallest, and the two frequency components obtained in the DOWN section are represented in order from the smallest. , F (d1) and f (d2). FIG. 10 is a diagram illustrating an example of data stored in the storage unit 33 in the first operation example. In the operation example 1, it is assumed that the measurement signal is transmitted at the basic transmission interval (time 1, 2, 3, 4) as shown in FIG.

  At time 1, the measurement signal 1 is transmitted, and as shown in FIG. 9, UP frequencies f (u 1) and f (u 2) are detected in the UP section, and DOWN frequencies f (d 1) and f (d 2) are detected in the DOWN section. It shall be detected. In this case, the detected frequencies f (u1), f (u2), f (d1), and f (d2) are stored in the storage unit 33. Further, the registration unit 34 refers to the frequency data registered in the storage unit 33 and searches for a pair of UP frequency and DOWN frequency having a difference smaller than the threshold frequency. The threshold frequency is not particularly limited, but is 0.1 Hz, for example. In this example, the UP frequency f (u1) and the DOWN frequency f (d2) are extracted for the measurement signal 1 transmitted at time 1.

  The registration unit 34 stores the sum of the extracted set of frequencies as distance data in a temporary registration table provided in the storage unit 33. In this example, “83.2 Hz (= 41.6 + 41.6)” is registered. Here, the sum of the UP frequency and the DOWN frequency is proportional to the distance r from the object detection device 1 to the target, as represented by the above-described equation (1). In addition, when the UP frequency and the DOWN frequency coincide with each other, it is generally highly likely that the target is a stationary object. Accordingly, “f (u1) + f (d2)” at time 1 is registered in the temporary registration table as distance data representing the distance from the object detection device 1 to the stationary object.

  However, even if the UP frequency and the DOWN frequency match each other, the target is not necessarily a stationary object. Therefore, the object detection apparatus 1 holds the distance data obtained at time 1 as temporary registration data.

  At time 2, the measurement signal 2 is transmitted, and the frequencies f (u1), f (u2), f (d1), and f (d2) are detected. Then, the registration unit 34 searches for a pair of UP frequency and DOWN frequency having a difference smaller than the threshold frequency. At time 2, the UP frequency f (u1) and the DOWN frequency f (d1) are extracted. Furthermore, the registration unit 34 calculates distance data corresponding to the extracted UP frequency and DOWN frequency pair. In this example, “83.2 Hz” is obtained as distance data based on “f (u1) + f (d1)”.

  The pair generation unit 35 compares the distance data obtained according to the measurement signal 2 at time 2 and the distance data already registered in the temporary registration table at the time 2. In this example, distance data “83.2 Hz” corresponding to the measurement signal 1 transmitted at time 1 is registered in the temporary registration table, and these distance data match each other. When the difference between the distance data is smaller than the predetermined threshold, the pair generation unit 35 determines that the UP frequency and the DOWN frequency extracted by the registration unit 33 are generated due to the stationary object. Then, the UP frequency and the DOWN frequency are paired. That is, a frequency pair “f (u1), f (d1)” for detecting a stationary object is obtained. Further, a frequency pair “f (u2), f (d2)” for detecting a moving object is obtained from the remaining frequency components.

  The distance data calculated at time 2 is registered in the storage unit 33 as new temporary registration data. This distance data is referred to in the measurement after time 3. The operation after time 3 is basically the same as the operation at time 2.

  As described above, when the frequency pair corresponding to the stationary object is obtained based on the measurement signal transmitted at a certain time, the object detection device of the embodiment checks whether or not a similar frequency pair has been registered in the past. . If a similar frequency pair has been registered in the past, pairing information for detecting a stationary target is output based on the frequency pair. Therefore, the frequency pair extraction accuracy for detecting a stationary object is improved, and the frequency pair extraction accuracy for detecting a moving object is also improved. As a result, the distance from the object detection device to the target and the speed of the target can be detected with high accuracy.

<Operation example 2>
FIG. 11 is a diagram illustrating the spectrum of the beat frequency obtained in the second operation example. In FIG. 11, the spectrum of the UP section and the DOWN section obtained from time 1 to time 3 is shown. In this example, UP frequencies f (u1) and f (u2) and DOWN frequencies f (d1) and f (d2) are obtained at each time.

  In the operation example 2, there is no UP frequency / DOWN frequency pair having a difference smaller than the threshold frequency with respect to the measurement signal transmitted at time 1. In this case, distance data is not registered in the temporary registration table. Further, the object detection device does not execute an algorithm for detecting another target after determining a frequency pair corresponding to a stationary object. Therefore, pairing of the UP frequency and the DOWN frequency is performed by another algorithm (for example, a method of pairing the UP frequency and the DOWN frequency in order of increasing beat frequency). In the example shown in FIG. 11, two frequency pairs “f (u1), f (d1)”, “f (u2), f (d2)” are generated, and targets are detected according to these frequency pairs. .

  When the measurement signal is transmitted at time 2, “f (u2), f (d1)” is obtained as a pair of the UP frequency and the DOWN frequency having a difference smaller than the threshold frequency. In this case, similarly to the operation example 1, distance data is calculated based on this frequency pair. And the pair production | generation part 35 checks whether the distance data whose difference with this distance data is smaller than a threshold value is already registered into the temporary registration table. In this example, the UP / DOWN frequency pair having the same frequency is not detected when measuring at time 1, and distance data is not registered in the temporary registration table at time 2. Therefore, the pair generation unit 35 performs pairing between the UP frequency and the DOWN frequency using the same algorithm as at time 1. The registration unit 34 registers the newly calculated distance data in the temporary registration table for pairing processing after time 3. At this time, the registered distance data is “f (u2) + f (d1)”.

  For the measurement signal transmitted at time 3, there is no UP frequency / DOWN frequency pair having a difference smaller than the threshold frequency. In this case, the distance data registered in the temporary registration table is discarded without being used. Then, the pair generation unit 35 performs pairing between the UP frequency and the DOWN frequency using the same algorithm as at time 1.

  Operation example 2 shows a situation in which, for example, two moving objects moving away from the object detection device exist within the radar range. That is, a pair of UP / DOWN frequencies having a difference smaller than the threshold frequency is generated not only due to a reflected wave from one stationary object but also due to a reflected wave from a plurality of moving objects. Can do. However, since the UP / DOWN frequency caused by the reflected wave from the moving object generally changes with time, it is extremely rare that the UP / DOWN frequency matches each other. Therefore, even if the object detection device of the embodiment detects a pair of UP / DOWN frequencies having a difference smaller than the threshold frequency, if the state does not continue, the object detection device uses the UP / DOWN frequency pair. Based on this, no stationary object is detected. As a result, erroneous pairing of UP / DOWN frequencies can be avoided, and target detection accuracy is improved.

<Operation example 3>
In the above-described operation examples 1 and 2, in order to improve the detection accuracy, when an UP / DOWN frequency pair that can obtain substantially the same distance data is repeatedly detected, a pair for detecting a stationary object is determined. The However, in this method, even when substantially the same UP / DOWN frequency pair is detected at a certain timing, if no distance data is registered in the temporary registration table at that time, a stationary object is detected. The UP / DOWN frequency pair for is not determined. For example, in the example shown in FIG. 9, when new distance data is calculated according to the measurement signal transmitted at time 1, distance data from the previous measurement is not registered in the temporary registration table. In this case, a stationary object cannot be detected using the measurement at time 1.

  Therefore, the object detection device according to the embodiment performs auxiliary measurement before the next measurement signal to be transmitted at the basic transmission interval if distance data obtained by the previous measurement is not registered when new distance data is calculated. A measurement signal for performing For example, in the embodiment shown in FIG. 6B, when new distance data 1 is calculated for the measurement signal 1, no past distance data is registered in the temporary registration table. In this case, before transmitting the measurement signal 2 at time 2, the object detection device 1 transmits the measurement signal 1a at time 1a in order to perform auxiliary measurement. When the object detection device 1 calculates new distance data 1a for the measurement signal 1a, the object detection device 1 compares the new distance data 1a with the previously calculated distance data 1 to detect a stationary object. The validity / invalidity of the pairing for detection is determined.

FIG. 12 is a flowchart illustrating a schematic operation of the object detection apparatus according to the embodiment. The process of this flowchart is executed by the control unit 12.
Step S1 is provided in order to repeatedly execute the processes of steps S2 to S5 at predetermined time intervals. The “predetermined time interval” corresponds to the basic transmission interval described above, and is 100 milliseconds in the example shown in FIG.

  In step S2, the output unit 37 of the control unit 12 outputs the result of the previous pairing process. Here, the pairing process corresponds to step S3 or S5. Thus, for example, in the processing loop executed at time 2, the processing result of step S3 or S5 executed at time 1 is output, and in the processing loop executed at time 3, the step executed at time 2 The processing result of S3 or S5 is output.

  In step S3, the control unit 12 executes pairing processing. The pairing process includes a procedure for transmitting a measurement signal, a procedure for detecting a beat signal corresponding to the measurement signal, and a procedure for generating a pair of an UP frequency and a DOWN frequency for each target using the beat signal. The pairing process will be described later in detail with reference to FIG.

  In step S4, the control unit 12 checks whether there is a target that cannot be determined whether it is a stationary object or a moving object. If there is a target that cannot be determined whether it is a stationary object or a moving object, step S5 is executed. On the other hand, when there is no target that cannot determine whether the object is a stationary object or a moving object, step S5 is not executed and the next processing loop is awaited. When the UP / DOWN frequency pair whose Doppler displacement is smaller than the threshold is detected, if distance data calculated based on the UP / DOWN frequency is not registered in the temporary registration table, step S4 is performed. It is determined as “Yes”.

  In step S5, the control part 12 performs the pairing process by auxiliary measurement. The pairing process by auxiliary measurement may be the same procedure as step S3 or may be a procedure different from step S3.

  As described above, the object detection apparatus according to the embodiment performs pairing between the UP frequency and the DOWN frequency at a constant time interval, and outputs the pairing result at a constant time interval. At this time, the object detection device outputs the pairing result at a constant time interval regardless of whether or not the auxiliary measurement in step S5 is executed. Here, the pairing result is used to calculate the distance to each target and / or the speed of each target, as shown in equations (1) and (2). Therefore, if the result of pairing between the UP frequency and the DOWN frequency is output at a constant time interval, processing such as the distance to the target, the speed of the target, the trajectory calculation of the moving object, or the movement direction estimation becomes easy.

  FIG. 13 is a flowchart showing the pairing process. This process corresponds to step S3 in FIG. That is, this pairing process is repeatedly executed by the control unit 12 at regular time intervals.

  In step S <b> 11, the transmission control unit 36 instructs the transmission unit 31 to transmit a measurement signal. As described with reference to FIG. 1, the measurement signal includes an UP section in which the frequency of the transmission wave increases linearly and a DOWN section in which the frequency of the transmission wave decreases linearly. The object detection device receives a reflected wave from the target, and generates a beat signal by mixing the transmission wave and the reception wave. The generated beat signal is converted into digital data and input to the control unit 12. In step S12, the control unit 12 detects a beat signal corresponding to the measurement signal transmitted in step S11. At this time, the control unit 12 detects beat frequencies (UP frequency and DOWN frequency) in each of the UP section and the DOWN section.

  In step S <b> 13, the pair generation unit 35 generates a pair with the round robin of the UP frequency and the DOWN frequency. Subsequently, in steps S14 to S15, the control unit 12 searches for a pair of an UP frequency and a DOWN frequency that have similar powers (or signal levels) and have a difference smaller than a predetermined threshold. . When an UP / DOWN frequency pair that satisfies the above conditions is detected, the control unit 12 calculates distance data corresponding to the UP / DOWN frequency pair. The distance data is represented by the sum of the detected UP frequency and DOWN frequency.

  In step S16, the control unit 12 checks whether or not distance data substantially the same as the distance data calculated in steps S14 to S15 is already registered in the temporary registration table. If the distance data is already registered in the temporary registration table, in step S17, the control unit 12 sets the UP / DOWN frequency detected in steps S13 to S14 as the UP / DOWN frequency corresponding to the stationary object. Confirm as a pair. The process for determining a pair is realized, for example, by setting a flag. If the distance data is not registered in the temporary registration table (step S16: No), step S17 is skipped. In step S18, the control unit 12 registers the distance data calculated in steps S14 to S15 in the temporary registration table.

  In step S19, the control unit 12 checks whether an unprocessed pair remains. If unprocessed pairs remain, the processes of steps S14 to S18 are executed. As described above, in steps S11 to S19, a pair of UP / DOWN frequencies corresponding to a stationary object is determined, and distance data to the stationary object is registered.

  In step S21, the pair generation unit 35 extracts a pair for which distance data is not registered. The pair extracted here is an UP / DOWN frequency pair representing a target that is not a stationary object, and the processes in and after step S22 are executed.

  In step S22, the control unit 12 searches for a pair of UP frequency and DOWN frequency having similar power (or signal level) as in step S14. If the powers are similar to each other, the distance data of the UP / DOWN frequency pair is registered in step S23. This distance data is registered as fixed data representing the distance to the moving object. At this time, the speed data of the moving object may also be registered. When the extracted pair of powers are not similar to each other, the control unit 12 determines that the combination of the UP frequency and the DOWN frequency is inappropriate and ends the process.

  In step S24, the control unit 12 checks whether an unprocessed pair remains. If unprocessed pairs remain, the processes of steps S22 to S23 are executed. By repeatedly executing steps S22 to S23, the distance data for each moving object is registered. In step S25, the control unit 12 initializes the temporary registration table except for the newly registered distance data (that is, data in the temporary registration state). That is, the data in the confirmed state is deleted from the temporary registration table. The data that remains in the temporary registration table corresponds to “a target that cannot be determined whether it is a stationary object or a moving object” in step S4 of FIG.

  The data in the confirmed state represents the distance to the target that is confirmed to be a stationary object or a moving object. Therefore, this data can also be used as a radar detection result. The pair distance data determined as a stationary object can also be used as a distance to a stationary object.

  The pairing process by auxiliary measurement executed in step S5 of FIG. 12 is the same as the pairing process shown in FIG. 13, for example. However, the pairing process by auxiliary measurement may be different from the pairing process shown in FIG. In this case, for example, the control unit 12 repeatedly transmits the measurement signal three times, and calculates the distance to the target using each measurement signal. When the same distance is calculated twice or more, the control unit 12 outputs the distance as a distance to the stationary object. Even in this case, the result data is output according to the basic transmission interval.

  Next, the operation example 3 will be specifically described with reference to FIGS. 6B and 14. In this example, it is assumed that distance data is not registered in the temporary registration table at time 1.

  At time 1, a frequency pair (f (u1), f (d1)) in which the Doppler displacement is zero is detected. In this case, the frequency pair (f (u1), f (d1)) is candidate data representing a stationary object. However, at time 1, distance data is not registered in the temporary registration table. Therefore, the frequency pair (f (u1), f (d1)) is not used as definite data representing a stationary object, and auxiliary measurement is performed. The distance data (f (u1) + f (d1)) corresponding to the frequency pair (f (u1), f (d1)) detected at time 1 is registered in the temporary registration table for subsequent processing. The At time 1, the pairing result obtained at time 0 is output.

  At time 1a, distance data (f (u1) + f (d1)) is registered in the temporary registration table. Then, as shown in FIG. 6B, the measurement signal 1a is transmitted, and the beat frequency corresponding to the measurement signal 1a is detected. At this time, in the example shown in FIG. 14, a frequency pair (f (u1a), f (d1a) having a Doppler displacement of zero is detected. In this case, the frequency pair (f (u1a), f) detected at time 1a. distance data (f (u1a) + f (d1a)) corresponding to f (d1a)) is calculated, followed by distance data (f (u1) + f (d1)) registered in the temporary registration table; The newly calculated distance data (f (u1a) + f (d1a)) is compared, and when these distance data match each other, the frequency pair obtained at time 1 or time 1a is stationary. The frequency pair representing the object is determined, and the remaining frequency components are paired to generate a frequency pair representing the moving object.

  At time 2, the result of the pairing process obtained from time 1 to time 1a is output. That is, the result of the pairing process is output at regular time intervals even when auxiliary measurement is performed. A measurement signal is also transmitted at time 2 and the same pairing process as at time 1 is executed.

<Hardware configuration of object detection device>
FIG. 15 is a diagram illustrating a hardware configuration of the control unit 12 of the object detection apparatus. In FIG. 15, the CPU 101 provides the object detection method of the embodiment by executing an object detection program using the memory 103. The storage device 102 stores an object detection program. Note that the storage device 102 may be an external storage device. The memory 103 is a semiconductor memory, for example, and includes a RAM area and a ROM area.

  The reading device 104 accesses the portable recording medium 105 according to an instruction from the CPU 101. The portable recording medium 105 includes, for example, a semiconductor device, a medium to / from which information is input / output by a magnetic action, and a medium to / from which information is input / output by an optical action. The communication interface 106 transmits / receives data via a network in accordance with instructions from the CPU 101. The input / output device 107 corresponds to, for example, a device that receives an instruction from a user.

The object detection program according to the embodiment is provided in the following form, for example.
(1) Installed in advance in the storage device 102.
(2) Provided by the portable recording medium 105.
(3) Download from the program server 110.

  The object detection apparatus according to the embodiment is realized by executing the object detection program with the processor system having the above configuration. That is, a part or all of the registration unit 34, the pair generation unit 35, the transmission control unit 36, the output 37, and the calculation unit 38 are realized by executing the object detection program of the embodiment on the processor system having the above configuration. The temporary registration table is created on the memory 103, for example.

The following supplementary notes are further disclosed with respect to the embodiments including the above examples.
(Appendix 1)
A transmission unit for transmitting a transmission wave including a frequency increase interval and a frequency decrease interval;
A beat signal generation unit that generates a beat signal of the transmission wave and a reflected wave corresponding to the transmission wave;
A storage unit for storing frequency information related to an ascending interval beat frequency detected in the frequency increasing interval and a falling interval beat frequency detected in the frequency decreasing interval;
When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, the frequency information includes the first rising section beat frequency and the first falling section beat frequency. A registration unit for registering distance data representing a first distance determined based on the storage unit;
When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, distance data in which the difference from the first distance is smaller than the threshold distance is stored in the storage unit. If already registered, a pair generation unit for pairing the first rising section beat frequency and the first falling section beat frequency;
Instructing the transmitter to transmit the transmission wave at a first time interval, and when the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency When distance data having a difference from the first distance smaller than the threshold distance is not registered in the storage unit, the transmission is performed to the transmission unit at a second time interval shorter than the first time interval. A transmission control unit for instructing transmission of waves;
An output unit that outputs a result of pairing by the pair generation unit at the first time interval;
An object detection apparatus having
(Appendix 2)
The object detection device according to attachment 1, wherein
When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, distance data in which the difference from the first distance is smaller than the threshold distance is the storage unit The transmission control unit causes the transmission unit to transmit one or a plurality of transmission waves before the next transmission wave transmitted at the first time interval. Object detection device.
(Appendix 3)
The object detection device according to appendix 1 or 2,
The apparatus further comprises a calculating unit that calculates a distance from the object detection device to the target based on the first rising section beat frequency and the first falling section beat frequency paired by the pair generation unit. An object detection device.
(Appendix 4)
The object detection device according to attachment 1, wherein
A second rising section beat frequency is detected in addition to the first rising section beat frequency in the frequency rising section, and a second falling section beat frequency in addition to the first falling section beat frequency in the frequency falling section. When an object is detected, the pairing unit performs pairing between the second rising section beat frequency and the second falling section beat frequency.
(Appendix 5)
The object detection device according to attachment 4, wherein
Based on the first rising section beat frequency and the first falling section beat frequency paired by the pair generation unit, the distance from the object detection device to the first target is calculated, and the pair generation The distance from the object detection device to the second target and the speed of the second target are calculated based on the second rising section beat frequency and the second falling section beat frequency paired by the unit. An object detection apparatus further comprising a calculation unit.
(Appendix 6)
The object detection device according to any one of appendices 1 to 5,
The distance data is represented by a sum of a corresponding rising section beat frequency and falling section beat frequency.
(Appendix 7)
Transmitter for transmitting a transmission wave including a frequency increase interval and a frequency decrease interval, a beat signal generation unit for generating a beat signal of the transmission wave and a reflected wave corresponding to the transmission wave, an increase detected in the frequency increase interval In an object detection apparatus comprising a storage unit and a processor for storing frequency information related to a section beat frequency and a falling section beat frequency detected in the frequency falling section, the processor includes:
When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, the frequency information includes the first rising section beat frequency and the first falling section beat frequency. A registration unit for registering distance data representing a first distance determined based on the storage unit;
When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, distance data in which the difference from the first distance is smaller than the threshold distance is stored in the storage unit. If already registered, a pair generation unit for pairing the first rising section beat frequency and the first falling section beat frequency,
Instructing the transmitter to transmit the transmission wave at a first time interval, and when the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency When distance data having a difference from the first distance smaller than the threshold distance is not registered in the storage unit, the transmission is performed to the transmission unit at a second time interval shorter than the first time interval. A transmission control unit for instructing transmission of waves,
An output unit that outputs a result of pairing by the pair generation unit at the first time interval;
Object detection program to function as

DESCRIPTION OF SYMBOLS 1 Object detection apparatus 12 Control part 13 Oscillator 22 Mixer 31 Transmission part 32 Beat signal generation part 33 Storage part 34 Registration part 35 Pair generation part 36 Transmission control part 37 Output part 38 Calculation part

Claims (5)

  1. A transmission unit for transmitting a transmission wave including a frequency increase interval and a frequency decrease interval;
    A beat signal generation unit that generates a beat signal of the transmission wave and a reflected wave corresponding to the transmission wave;
    A storage unit for storing frequency information related to an ascending interval beat frequency detected in the frequency increasing interval and a falling interval beat frequency detected in the frequency decreasing interval;
    When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, the frequency information includes the first rising section beat frequency and the first falling section beat frequency. A registration unit for registering distance data representing a first distance determined based on the storage unit;
    When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, distance data in which the difference from the first distance is smaller than the threshold distance is stored in the storage unit. If already registered, a pair generation unit for pairing the first rising section beat frequency and the first falling section beat frequency;
    Instructing the transmitter to transmit the transmission wave at a first time interval, and when the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency When distance data having a difference from the first distance smaller than the threshold distance is not registered in the storage unit, the transmission is performed to the transmission unit at a second time interval shorter than the first time interval. A transmission control unit for instructing transmission of waves;
    An output unit that outputs a result of pairing by the pair generation unit at the first time interval;
    An object detection apparatus having
  2. The object detection device according to claim 1,
    When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, distance data in which the difference from the first distance is smaller than the threshold distance is the storage unit The transmission control unit causes the transmission unit to transmit one or a plurality of transmission waves before the next transmission wave transmitted at the first time interval. Object detection device.
  3. The object detection device according to claim 1 or 2,
    The apparatus further comprises a calculating unit that calculates a distance from the object detection device to the target based on the first rising section beat frequency and the first falling section beat frequency paired by the pair generation unit. An object detection device.
  4. The object detection device according to claim 1,
    A second rising section beat frequency is detected in addition to the first rising section beat frequency in the frequency rising section, and a second falling section beat frequency in addition to the first falling section beat frequency in the frequency falling section. When an object is detected, the pairing unit performs pairing between the second rising section beat frequency and the second falling section beat frequency.
  5. Transmitter for transmitting a transmission wave including a frequency increase interval and a frequency decrease interval, a beat signal generation unit for generating a beat signal of the transmission wave and a reflected wave corresponding to the transmission wave, an increase detected in the frequency increase interval In an object detection apparatus comprising a storage unit and a processor for storing frequency information related to a section beat frequency and a falling section beat frequency detected in the frequency falling section, the processor includes:
    When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, the frequency information includes the first rising section beat frequency and the first falling section beat frequency. A registration unit for registering distance data representing a first distance determined based on the storage unit;
    When the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency, distance data in which the difference from the first distance is smaller than the threshold distance is stored in the storage unit. If already registered, a pair generation unit for pairing the first rising section beat frequency and the first falling section beat frequency,
    Instructing the transmitter to transmit the transmission wave at a first time interval, and when the difference between the first rising section beat frequency and the first falling section beat frequency is smaller than the threshold frequency When distance data having a difference from the first distance smaller than the threshold distance is not registered in the storage unit, the transmission is performed to the transmission unit at a second time interval shorter than the first time interval. A transmission control unit for instructing transmission of waves,
    An output unit that outputs a result of pairing by the pair generation unit at the first time interval;
    Object detection program to function as
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Citations (4)

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JP2003240843A (en) * 2002-02-19 2003-08-27 Denso Corp Fmcw radar unit and program
JP2007003476A (en) * 2005-06-27 2007-01-11 Nissan Motor Co Ltd Object detector and object detecting method
JP2008111779A (en) * 2006-10-31 2008-05-15 Fujitsu Ltd Object detector and object detecting method
JP2009145282A (en) * 2007-12-17 2009-07-02 Fujitsu Ltd Fmcw radar device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003240843A (en) * 2002-02-19 2003-08-27 Denso Corp Fmcw radar unit and program
JP2007003476A (en) * 2005-06-27 2007-01-11 Nissan Motor Co Ltd Object detector and object detecting method
JP2008111779A (en) * 2006-10-31 2008-05-15 Fujitsu Ltd Object detector and object detecting method
JP2009145282A (en) * 2007-12-17 2009-07-02 Fujitsu Ltd Fmcw radar device

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