JP2006090800A - Radar equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse radar device capable of accurately detecting an object existing from a short distance area to a long distance area.
In a pulse radar device, during a short range mode, an oscillator 12 generates a carrier wave having a constant frequency, and a pulse generator 13 repeatedly generates a first pulse having a relatively short pulse width. The modulation unit 14 modulates the carrier wave with the first pulse to generate the first high-frequency pulse. Further, during the long distance mode, the oscillator 12 generates a chirp signal swept between a low frequency and a high frequency, and the pulse generator 13 generates a second pulse having a relatively long pulse width, Further, the modulation unit 14 modulates the chirp signal with the second pulse to generate a second high-frequency pulse. The transmitting antenna transmits the first high-frequency pulse and the second high-frequency pulse as described above to the space.
[Selection] Figure 1

Description

  The present invention relates to a radar apparatus, and more particularly to a radar apparatus that detects a distance to a surrounding object by receiving and processing a reflected wave of a high-frequency signal transmitted by itself.

  One known radar device is a so-called pulse radar device. First, the pulse radar device sends a pulsed high-frequency signal (hereinafter referred to as a high-frequency pulse signal) to the space. Thereafter, the pulse radar device receives the reflected pulse signal from the object, and obtains the distance to the object based on the time from when the high frequency pulse is transmitted until the reflected pulse signal is received. An advantage of the pulse radar device is that a plurality of objects located at different distances can be detected.

Among the parameters indicating the performance of such a palace radar device, the distance resolution Rres, that is, the minimum distance difference that can be confirmed by separating two objects in the same scanning direction is approximately proportional to the pulse width τ, and 1).
Rres = c · τ / 2 (1)
Here, c is the speed of light.

  Furthermore, the accuracy of the measured distance also greatly depends on the accuracy of the reference clock used and / or the calculation accuracy of the processor, but in the case of a pulse radar device, it also largely depends on the pulse width τ.

  Also, when the antenna for transmitting the high-frequency pulse signal and the antenna for receiving the reflected pulse signal are shared, the minimum distance that can be measured is the state in which the transmission / reception switcher is in the reception state after the high-frequency pulse signal starts to be output. It is determined by the time until it becomes, and is approximately the same as the pulse width τ.

  In recent years, there has been a growing need for short-range radar devices (short range radar) that measure the distance to objects in a short-range region with high accuracy and high resolution by making the pulse width extremely short. Legislation has also been made.

On the other hand, in order to increase the maximum detection distance, a large energy is required, so that the pulse width needs to be increased. In this case, there has been proposed a pulse radar device that modulates a basic pulse signal with various methods instead of modulating with a carrier wave having a constant frequency. As a typical example, a method of modulating a pulse signal with a carrier wave (chirp signal) whose frequency has been swept has been proposed (see, for example, Patent Document 1). Specifically, a chirp signal is used, a pulse compression receiver is added, and when a reflected signal from an object is received, the S / N ratio ( Signal to Noise Ratio) is improved to increase the detection distance.
JP 2001-116839 A

  However, in the short-range radar apparatus, the pulse width is set to be short in order to shorten the minimum distance that can be measured, and thus the frequency band of the high-frequency pulse signal to be transmitted is widened. Such a spread of the frequency band may cause interference with other wireless systems, so the transmission output of the short-range radar apparatus is kept low due to legal regulations. As a result, the short-range radar apparatus has a problem that the maximum detection distance becomes small and an object in a long-distance region cannot be detected.

  On the other hand, the pulse compression radar apparatus disclosed in the above publication can detect an object in a longer distance region as the pulse width is longer due to the effect of pulse compression. However, the pulse compression radar apparatus correlates a replica of a high-frequency pulse signal to be transmitted with a reflected pulse signal from an object. For accurate correlation processing, the frequency of the reflected pulse signal from the object needs to change in the same manner as the frequency of the high-frequency pulse signal to be transmitted. However, since the waveform after pulse compression is disturbed in the actual reflected pulse signal, the accuracy of the distance to be detected is reduced, and the pulse compression radar apparatus is capable of detecting an object at a short distance that requires accurate and fine resolution. Has the problem of being unsuitable.

  Therefore, an object of the present invention is to provide a pulse radar device that can accurately detect an object existing from a short-distance region to a long-distance region.

  In order to achieve the above object, one aspect of the present invention is a radar apparatus that detects a distance to a surrounding object by receiving and processing a reflected wave of a high-frequency signal transmitted by itself, and includes a short-distance mode. And a mode designating unit that designates either of the long-distance mode and the mode designating unit repeatedly generates the first pulse having a relatively short pulse width while the mode designating unit designates the short-distance mode. While the distance mode is specified, a pulse generation unit that generates a second pulse having a relatively long pulse width and a carrier wave having a constant frequency while the mode specification unit specifies the short distance mode While the mode designation unit designates the long distance mode, an oscillator that generates a chirp signal swept between a low frequency and a high frequency and the mode designation unit designates the short distance mode. During, pulse raw The first high-frequency pulse is generated by modulating the carrier wave generated by the oscillator with the first pulse generated by the unit, and is generated by the pulse generation unit while the mode specifying unit specifies the long distance mode. The second pulse is used to modulate the chirp signal generated by the oscillator to generate the second high-frequency pulse, and while the mode designating unit designates the short-range mode, A transmission antenna that transmits the first high-frequency pulse to the space, and transmits the second high-frequency pulse modulated by the modulation unit to the space while the mode specifying unit specifies the long-distance mode.

  Preferably, the radar apparatus generates a first replica pulse based on the first high-frequency pulse generated by the modulation unit while the mode specifying unit specifies the short-distance mode, and the mode specifying unit While specifying the long distance mode, the delay circuit that generates the second replica pulse based on the second high-frequency pulse generated by the modulation unit, and the first high-frequency pulse transmitted from the transmitting antenna or The receiving antenna receiving the first reflected pulse or the second reflected pulse reflected by the second high frequency pulse hitting the object, and the first generated by the delay circuit while the mode designating unit designates the short distance mode. 1 replica pulse and the first reflected pulse received by the receiving antenna are output to output a first correlation signal. While the mode designation unit designates the long-distance mode, A correlator that correlates the second replica pulse generated in step 2 and the second reflected pulse received by the receiving antenna and outputs a second correlation signal, and the first or the output from the correlator A detector that detects the second correlation signal and outputs a first detection result indicating that an object is present in the short-range range or a second detection result indicating that an object is present in the long-range range; And a calculation unit for obtaining a distance to the object based on the first or second detection result output from the detector, and an output unit for outputting information representing the distance obtained by the calculation unit to the user. . Here, the delay circuit generates the second replica pulse in a time period corresponding to the repetition period of the first pulse generated by the pulse generation unit while the mode specifying unit specifies the long distance mode. do not do.

  Also, preferably, the radar apparatus is information indicating whether or not an object is detected in the short distance range during the short distance mode, or whether or not an object is detected in the long distance range during the long distance mode. A result information storage unit for storing information indicating the above, and the mode designating unit designates either the short distance mode or the long distance mode based on the information stored in the result information storage unit.

  Preferably, the radar apparatus further includes a vehicle information acquisition unit that periodically acquires state information indicating the current state of the vehicle, and the mode designating unit is configured to receive the near information based on the vehicle information acquired by the vehicle information acquisition unit. Specify either distance mode or long distance mode.

  For example, the pulse generation unit generates a first pulse at a first repetition period, and generates a second pulse at a second repetition period longer than the first repetition period. Alternatively, the pulse generator generates the first and second pulses at random time intervals.

  As described above, according to the present pulse radar device, the first high-frequency pulse in which the carrier wave having a constant frequency is modulated by the first pulse having a relatively short pulse width during the short-distance mode is sent to the space. During the long distance mode, a second high-frequency pulse in which a chirp signal having a swept frequency is modulated with a second pulse having a relatively long pulse width is transmitted to the space. Such a short distance mode and a long distance mode are switched by the mode designation unit. As a result, the pulse radar device alone can accurately detect an object existing from a short-distance region to a long-distance region.

(Embodiment)
FIG. 1 is a block diagram showing a configuration of a pulse radar device 1 according to an embodiment of the present invention. In FIG. 1, a pulse radar device 1 includes a control unit 11, an oscillator 12, a pulse generation unit 13, a modulation unit 14, a filter 15, an amplifier 16, a transmission antenna 17, a delay circuit 18, and a reception. Antenna 19, a low-noise amplifier (hereinafter referred to as LNA (Low Noise Amplifier)) 20, a filter 21, a correlator 22, a detector 23, a calculation unit 24, and an output unit 25. .

  In order to control each component of the pulse radar device 1, the control unit 11 includes at least a mode specifying unit 111, an oscillation frequency specifying unit 112, a timing specifying unit 113, a pulse width specifying unit 114, and a delay time specifying. Part 115.

  The mode designating unit 111 generates a mode designating signal Smode as shown in FIG. 2 and outputs it to the oscillation frequency designating unit 112, the timing designating unit 113, the pulse width designating unit 114, and the delay time designating unit 115. The mode designation signal Smode indicates whether the pulse radar device 1 operates in the short distance mode Ma or the long distance mode Mb. In the present embodiment, the short distance mode Ma and the long distance mode Mb appear alternately. Here, in the following description, the length of the time interval in the short distance mode Ma is Pa, and the length of the time interval in the long distance mode Mb is Pb. Further, a combination of the short distance mode Ma and the long distance mode Mb is referred to as a unit cycle UC.

  In FIG. 1 again, the oscillation frequency designating unit 112 generates a frequency control signal Sfreq indicating the oscillation frequency of the oscillator 12 according to the input mode signal Smode, and outputs the frequency control signal Sfreq to the oscillator 12. The frequency control signal Sfreq is a signal for instructing the oscillation frequency of the oscillator 12 to be substantially constant while the input mode signal Smode indicates the short-distance mode Ma. While shown, it is a signal for instructing to sweep the oscillation frequency from a low frequency to a high frequency.

  The timing designation unit 113 generates and outputs a timing signal Sclk indicating the repetition period of the pulses generated by the pulse generation unit 13 in accordance with the input mode signal Smode. As shown in FIG. 2, the timing signal Sclk indicates a relatively short repetition period Ta while the input mode signal Smode indicates the short distance mode Ma, and conversely, while the long distance mode Mb is indicated. A relatively long repetition period Tb is shown. Here, Ta is determined based on the maximum detection distance of the pulse radar device 1 in the short-range mode Ma. If the maximum sensing distance is about 10 meters, Ta is illustratively set to 67 nanoseconds. Tb is determined based on the maximum detection distance in the long-distance mode, and is selected to be at least larger than Ta. Further, the total number of repetition periods Ta in one short distance mode Ma and the total number of repetition periods Tb in one long distance mode Mb are respectively determined in advance.

  The pulse width specifying unit 114 generates a pulse width specifying signal Swidth indicating the pulse width of the pulse generated by the pulse generating unit 13 according to the input mode signal Smode, and outputs the pulse width specifying signal Swidth to the pulse generating unit 13. The pulse width designation signal Swidth indicates a relatively short pulse width τa during the short distance mode Ma, and conversely indicates a relatively long pulse width τb during the long distance mode Mb. Here, τa is preferably selected to be as small as possible, and τb is selected to be at least larger than τa because large energy is required to increase the maximum detection distance.

  The delay time designation unit 115 generates and outputs a delay time designation signal Sdelay for designating the amount of delay that the delay circuit 18 gives to the output signal of the modulation unit 14 in accordance with the input mode signal Smode.

  Specifically, as shown in FIG. 2, the delay time designating unit 115 generates one clock when the time of i × ΔTa elapses after the start of each repetition period Ta in the short distance mode Ma. The first replica pulse FRP (details will be described later) is instructed to be output according to a different clock. Here, i is a natural number indicating how many clocks are input from the start of each short distance mode Ma, and is a natural number from 1 to I. ΔTa is determined by the design specifications of the pulse radar device 1, and is preferably set as small as possible from the viewpoint of increasing the distance resolution (resolution). ΔTa is equal to or less than Ta / I. Further, I is the total number of clocks included in the delay time designation signal Sdelay in one short distance mode.

  In addition, as shown in FIG. 2, the delay time designating unit 115 passes the time j × ΔTb after the time I × ΔTa has elapsed from the start of the repetition period Tb during each repetition period Tb in the long distance mode Mb. Then, one clock is generated. The delay time designating unit 115 instructs the delay circuit 18 to output a second replica pulse SRP (details will be described later) according to such a clock. Here, j is a natural number indicating how many clocks are input from the start of each long distance mode Mb, and is a natural number from 1 to J. ΔTb is determined based on the design specification in the same manner as ΔTa, and is preferably set as small as possible from the viewpoint of increasing the resolution. ΔTb is equal to or less than (Tb−I × ΔTa) / J. Furthermore, J is the total number of clocks included in the delay time designation signal Sdelay in one long distance mode. In the present embodiment, in one long distance mode, the total number of clocks included in the timing signal Sclk is the same as the total number of clocks included in the delay time designation signal Sdelay.

  As will be described in detail later, the pulse radar device 1 can be operated in a short distance mode Mb in the long distance mode Mb by not generating a clock between the start of the repetition period Tb and the time I × ΔTa. An object that can exist in the range is not detected. In the following description, a time zone from the start of the repetition period Tb to time I × ΔTa is referred to as a dead zone.

  The delay time designation unit 115 outputs a signal having a time waveform represented by the clock as described above as a delay time designation signal Sdelay. The delay time designation signal Sdelay is also given to the detector 23 in order to designate the operation timing of the detector 23.

  Next, the oscillator 12 oscillates according to the frequency control signal Sfreq output from the oscillation frequency specifying unit 112, generates a high frequency signal HS, and outputs the high frequency signal HS to the modulation unit 14. Specifically, the oscillator 12 outputs an electric signal having a constant high frequency as the high frequency signal HS while the input frequency control signal Sfreq indicates a constant frequency. On the other hand, while the input frequency control signal Sfreq indicates that the frequency is swept, a chirp signal having the swept frequency is output as the high-frequency signal HS.

  The pulse generation unit 13 generates and outputs a pulse signal PS in accordance with the timing signal Sclk from the timing specification unit 113 and the pulse width specification signal Swidth from the pulse width specification unit 114. Specifically, as shown in FIG. 2, the pulse generator 13 generates a first pulse FP having a pulse width τa and a repetition period Ta during the short distance mode Ma, and the long distance mode Mb. Meanwhile, a second pulse SP having a pulse width τb and a repetition period Tb is generated. Therefore, the pulse generator 13 outputs a pulse signal PS including I first pulses FP and J second pulses SP per unit cycle.

  The modulation unit 14 modulates the high frequency signal HS from the oscillator 12 with the pulse signal PS from the pulse generation unit 13 to generate and output a high frequency pulse signal PHS. As shown in FIG. 2, the time waveform of such a high-frequency pulse signal PHS includes a first high-frequency pulse FHP having a constant frequency in the time zone corresponding to the pulse width τa during the short distance mode Ma (illustrated first). 2) appear at every repetition period Ta, and during the long distance mode Mb, the frequency is swept in a time zone corresponding to the pulse width τb, and the second high-frequency pulse SHP (represented by Only) appears. The high-frequency pulse signal PHS as described above is output to the HPF 15 and the delay circuit 18.

  The delay circuit 18 gives a delay amount to the inputted high frequency pulse signal PHS according to the delay time designation signal Sdelay output from the delay time designation unit 115 to generate a replica pulse signal RPS of the high frequency pulse signal PHS, and a correlator 22. Output to.

  Specifically, as shown in FIG. 3, in the short distance mode Ma, the delay circuit 18 is inputted this time as soon as a clock constituting the delay time designation signal Sdelay is given during the repetition period Ta. A replica (hereinafter referred to as a first replica pulse) FRP of the first high-frequency pulse FHP (shown by a dotted line) is generated and output to the correlator 22. That is, the first replica pulse FRP is output every i × ΔTa after the start of the current repetition period Ta.

  Further, in the long distance mode Mb, the delay circuit 18 receives the second high-frequency pulse SHP (shown by a dotted line) inputted this time as soon as a clock constituting the delay time designation signal Sdelay is given during the repetition period Tb. A replica (hereinafter referred to as a second replica pulse) SRP is generated and output to the correlator 22. That is, the second replica pulse SRP is output every time j × ΔTb after the dead zone I × ΔTa has elapsed.

  The delay circuit 18 generates a replica pulse signal RPS composed of I first replica pulses FRP and J second replica pulses SRP during each unit cycle UC by the method as described above. And output to the correlator 22.

  Further, as described above, the high-frequency pulse signal PHS is also output to the filter 15. The high-frequency pulse signal PHS is amplified by the amplifier 16 after being removed from the unnecessary frequency component by the filter 15 and sent out from the transmitting antenna 17 to the space. In FIG. 3, the time waveform of such a high-frequency pulse signal PHS is also drawn immediately below the replica pulse signal RPS for reference.

  The high-frequency pulse signal PHS transmitted as described above is reflected at the same time when the object A exists in the short distance range and the object B exists in the long distance range. Become. More specifically, since the first high-frequency pulse FHP with low energy is transmitted in the time zone Pa, the first high-frequency pulse FHP does not reach the far range. Therefore, the receiving antenna 19 receives only the reflected pulse rPa from the object A every time the first high-frequency pulse FHP is transmitted in the time zone Pa. On the other hand, since the high-energy second high-frequency pulse SHP is transmitted in the time zone Pb, the second high-frequency pulse SHP hits both the object A and the object B and is reflected. Therefore, the receiving antenna 19 receives the reflected pulse rPa 'from the object A and the reflected pulse rPb from the object B every time the second high-frequency pulse SHP is transmitted in the time zone Pb. Therefore, in the above case, the output signal (hereinafter referred to as a reflected pulse signal) rPS of the receiving antenna 19 has a waveform as depicted directly below the high-frequency pulse signal PHS in FIG.

  The reflected pulse signal rPS as described above is received by the receiving antenna 19, amplified by the LNA 20, unnecessary frequency components are removed by the filter 21, and then input to the correlator 22.

  The correlator 22 correlates the replica pulse signal RPS output from the delay circuit 18 and the reflected pulse signal rPS output from the filter 21, generates a correlation signal CS, and outputs the correlation signal CS to the detector 23. The time waveform of the correlation signal CS has a pulse waveform when the reflected pulse signal rPS and the replica pulse signal RPS are correlated during the short distance mode Ma. On the other hand, the time waveform of the correlation signal CS has a pulse-compressed waveform when the correlation is obtained during the long distance mode Mb. That is, a sharp peak appears in the correlation signal CS.

  Here, in FIG. 3, the reflected pulses rPa and rPa ′ are received when the time τ1 has elapsed after the transmission of the first high-frequency pulse FHP and the second high-frequency pulse SHP, respectively. It is assumed that the signal is received when time τ2 has elapsed after the transmission of the high-frequency pulse SHP. Also, τ1 is assumed to be substantially equal to 2 × ΔTa. Under such an assumption, as shown in FIG. 3, the first replica pulse FRP generated at the second repetition period Ta and the reflected pulse rPa are input to the correlator 22 almost simultaneously, so that the short distance In the mode, the correlator 22 outputs a correlation signal CS having a pulse waveform. However, since the correlation cannot be obtained at other timings, the correlator 22 outputs substantially nothing.

  It is also assumed that τ2 is substantially equal to time I × ΔTa + 2 × ΔTb). Under such an assumption, as shown in FIG. 3, the second replica pulse SRP generated in the second repetition period Tb and the reflected pulse rPb are input to the correlator 22 almost simultaneously. 22 outputs a correlation signal CS having a sharp peak PKb as shown. Since no clock is supplied from the delay time designating unit 115 until the dead zone I × ΔTa elapses after the start of the long distance mode Mb, even if the reflected pulse rPa ′ is input to the correlator 22 during this period. A sharp peak does not appear in the correlation signal CS. Thus, by providing the dead zone I × ΔTa, it is possible to prevent the object A existing in the short distance range from being detected in the long distance mode Mb.

  The detector 23 operates in response to each clock constituting the input delay time designation signal Sdelay. Specifically, the detector 23 detects the correlation signal CS output from the correlator 22 at the start of operation, generates a detection result DS indicating whether or not a peak is set, and outputs the detection result DS to the arithmetic processing unit 24. To do. The calculation unit 24 calculates the distance D from the pulse radar apparatus 1 to the detected object based on a known method. The output unit 25 provides the user with the distance D calculated by the calculation unit 24.

  Next, the operation of the pulse radar device 1 shown in FIG. 1 will be described in detail with reference to the flowchart of FIG. In FIG. 4, first, the mode designating unit 111 generates a mode designating signal Smode (see FIG. 2) indicating the short distance mode Ma, and generates an oscillation frequency designating unit 112, a timing designating unit 113, a pulse width designating unit 114, and a delay. It outputs to the time designation | designated part 115 (step S1).

  In response to the current mode designation signal Smode, the oscillation frequency designation unit 112 generates a frequency control signal Sfreq for making the oscillation frequency of the oscillator 12 constant and outputs it to the oscillator 12 (step S2).

  Further, in response to the current mode signal Smode, the timing specifying unit 113 outputs a timing signal Sclk (see FIG. 2) indicating a relatively short repetition period Ta to the pulse generation unit 13 (step S3).

  In response to the current mode signal Smode, the pulse width designation unit 114 outputs a pulse width designation signal Swidth indicating a relatively short pulse width τa to the pulse generation unit 13 (step S4).

  Further, in response to the current mode signal Smode, the delay time specifying unit 115 generates one clock each time i × ΔTa has elapsed after the start of the i-th repetition period Ta, thereby Then, a delay time designation signal Sdelay (see FIG. 2) indicating the output timing of the first replica pulse FRP is output to the delay circuit 18. The delay time designating circuit Sdelay is also output to the detector 23 in order to control the operation timing of the detector 23 (step S5).

  When the setting as described above is completed, the pulse radar device 1 detects the object existing in the short-range range as described above during the short-range mode Ma and indicates the distance of the detected object. Information is provided to the user (step S6).

  When the processing of the short distance mode Ma is completed, the mode specifying unit 111 generates a mode specifying signal Smode (see FIG. 2) indicating the long distance mode Mb, and the oscillation frequency specifying unit 112, the timing specifying unit 113, It outputs to the pulse width designation | designated part 114 and the delay time designation | designated part 115 (step S7).

  In response to the current mode designation signal Smode, the oscillation frequency designation unit 112 generates a frequency control signal Sfreq for sweeping the oscillation frequency of the oscillator 12 and outputs it to the oscillator 12 (step S8).

  Further, in response to the current mode signal Smode, the timing specifying unit 113 outputs a timing signal Sclk (see FIG. 2) indicating a relatively long repetition period Tb to the pulse generation unit 13 (step S9).

  In response to the current mode signal Smode, the pulse width specifying unit 114 outputs a pulse width specifying signal Swidth indicating a relatively long pulse width τb to the pulse generating unit 13 (step S10).

  Furthermore, in response to the current mode signal Smode, the delay time designating unit 115 waits for the dead zone I × ΔTa after the start of the j-th repetition period Ta, and then every time j × ΔTb elapses. One clock is generated, and one clock is generated every time ΔTb elapses, whereby a delay time designation signal Sdelay (see FIG. 2) indicating the timing of outputting the second replica pulse SRP is generated. Output to the delay circuit 18. The delay time designating circuit Sdelay is also output to the detector 23 in order to control the operation timing of the detector 23 (step S11).

  When the above settings are completed, the pulse radar device 1 detects the object existing in the long distance range and indicates the distance of the detected object as described above during the long distance mode Mb. Information is provided to the user (step S12).

  As described above, according to the present pulse radar device 1, the mode designating unit 111 designates the short distance mode Ma and the long distance mode Mb. During the short distance mode Ma, the oscillation frequency specifying unit 112 controls the oscillation frequency of the oscillator 12 to be constant, and the timing specifying unit 113 sets the repetition period of the pulses to be generated by the pulse generating unit 13 to be short, and the pulse width The designation unit 114 sets a short pulse width generated by the pulse generation unit 13 and generates a high-frequency pulse signal PHS suitable for detecting an object in the short-range range. Further, during the long distance mode Mb, the oscillation frequency designation unit 112 controls to sweep the oscillation frequency of the oscillator 12, and the timing designation unit 113 sets a long repetition period of the pulses to be generated by the pulse generation unit 13. The pulse width specifying unit 114 sets the width of the pulse generated by the pulse generating unit 13 to be long, and generates a high-frequency pulse signal PHS suitable for detecting an object in the long distance range during the long distance mode Mb. . As a result, the present pulse radar device 1 alone can accurately detect an object existing from a short-distance region to a long-distance region.

  Further, in the long distance mode of the pulse radar device 1, the delay circuit 18 does not generate the second replica pulse SRP until the dead zone I × ΔTa elapses after the second high frequency pulse SHP is applied. As a result, in the long-distance mode, even if the reflected pulse rPa 'from the object existing in the short-distance range is returned, the correlator 22 cannot take a correlation. That is, according to the present pulse radar device 1, an object in the short-range range is detected using the first high-frequency pulse FHP directed toward the short-range range, and a near-range range is detected using the second high-frequency pulse SHP directed toward the long-range range. Since an object in the distance range is not detected, the object can be detected with high accuracy.

  In the above description, the delay time designating unit 15 generates one clock when the time of i × ΔTa has elapsed after the start of each repetition period Ta in the short distance mode Ma (see FIG. 2). . However, the present invention is not limited to this, and the delay time designating unit 15 may repeatedly generate a clock at an interval of time ΔTa after the start of the repetition period Ta in the short distance mode Ma. Similarly, the delay time designating unit 15 may repeatedly generate a clock at an interval of time ΔTb after the start of each repetition period Tb in the long distance mode Mb.

  In the above description, in the short distance mode Ma, one clock is generated when the time of i × ΔTa has elapsed after the start of each repetition period Ta, and I pulses are transmitted in total during the time Pa. In this case, by repeating Pa several times (Na times), the calculation unit 24 performs object detection processing using a signal obtained by integrating the signal from the detector 23 Na times, thereby detecting the object detection accuracy. May be improved. Similarly, in the long-distance mode Mb, after starting each repetition period Tb, J pulses were sent in total during time Pb to detect the object, but Pb is repeated a plurality of times (Nb times). Thus, the calculation unit 24 may perform object detection processing using a signal obtained by integrating the signal from the detector 23 Nb times to improve the object detection accuracy. The same applies to the case where the unit cycle UC is repeated a plurality of times.

(First modification)
FIG. 5 is a block diagram showing a configuration of a pulse radar apparatus 1a according to the first modification of the present invention. In FIG. 5, the pulse radar device 1a is different from the pulse radar device 1 shown in FIG. 1 in that a detection result storage unit 26 is further provided. There are no other structural differences between the two pulse radar apparatuses 1 and 1a. Therefore, in FIG. 5, the same reference numerals are assigned to the components corresponding to the configuration shown in FIG.

  The result information storage unit 26 stores information (hereinafter referred to as a detection flag) indicating whether or not an object is detected in the short distance range during the short distance mode Ma. In the following, for convenience of explanation, it is assumed that “1” as a detection flag indicates that an object is detected in the short-range range, and “0” indicates that it is not.

  Next, the operation of the pulse radar device 1a shown in FIG. 5 will be described in detail with reference to the flowchart of FIG. 6 is different from FIG. 4 in that steps S13 to S15 are further included. Other than that, there is no difference between the two flowcharts. Therefore, in FIG. 6, the steps corresponding to the steps shown in FIG.

  In FIG. 6, after the pulse radar device 1a executes steps S1-S6, when the calculation unit 24 detects an object in the short distance mode Ma (Yes in step S13), the detection held in the result information storage unit 26 is detected. The flag is updated to “1” (step S14).

  When the calculation unit 24 does not detect an object in the short distance mode Ma (No in step S13) or after step S14, the mode designation unit 111 sets the detection flag in the result information storage unit 26 to “1”. Is determined (step S15).

  If it is determined Yes, the mode designating unit 111 performs Step S1, but if it is determined No, it performs Step S7.

  As described above, according to the present pulse radar 1a, when an object is detected in the short distance mode Ma, the short distance mode Ma is continued. As a result, the user can continue to check an object in the short distance range on the output unit 25.

  Contrary to the above, the result information storage unit 26 stores information indicating whether or not an object is detected in the long distance range during the long distance mode Mb, and the mode designating unit 111 performs step S15. In step S7, if it is determined as Yes, step S7 may be performed.

(Second modification)
FIG. 7 is a block diagram showing a configuration of a pulse radar apparatus 1b according to the second modification of the present invention. In FIG. 7, the pulse radar device 1 b is different from the pulse radar device 1 shown in FIG. 1 in that it further includes a vehicle information storage unit 27. There are no other structural differences between the two pulse radar apparatuses 1 and 1b. Therefore, in FIG. 7, components corresponding to those shown in FIG.

  The vehicle information acquisition unit 27 periodically acquires state information indicating the current state of the vehicle, which is a typical example in which the present pulse radar device 1b is installed. The state information is typically a vehicle moving speed, steering angle, angular velocity, or shift position.

  Next, the operation of the pulse radar device 1b shown in FIG. 7 will be described in detail with reference to the flowchart of FIG. 8 differs from FIG. 4 in that step S16-18 is further included. Other than that, there is no difference between the two flowcharts. Therefore, in FIG. 8, the same step numbers are assigned to the steps corresponding to the steps shown in FIG.

  In FIG. 8, after the pulse radar device 1b executes steps S1-S6, the vehicle information acquisition unit 27 acquires the moving speed of the vehicle, which is one of the state information, and passes it to the mode specification unit 111 (step S16). .

  Next, the mode designating unit 111 determines whether or not the moving speed received this time is equal to or less than a predetermined reference value (step S17). In the description of this modification, the reference value is a value that can be considered that the vehicle is traveling at a low speed, and is illustratively 20 km / h.

  If it is determined Yes, the mode designating unit 111 performs Step S1, but if it is determined No, it performs Step S7.

  In general, when the vehicle is moving at a low speed (for example, when parked), the user is interested in objects in the short range. Therefore, according to the present pulse radar 1b, when the vehicle is moving at a low speed after the execution of the short distance mode Ma, the short distance mode Ma is continued. As a result, the user can continue to check an object in the short distance range on the output unit 25.

  Contrary to the above, if the mode designating unit 111 determines that the moving speed obtained from the vehicle information obtaining unit 27 can be regarded as high after the long distance mode Mb is over, the mode designating unit 111 performs step S7. It doesn't matter.

  In addition, when the state information is the steering angle or the angular velocity, the mode designating unit 111 determines that the steering angle or the angular velocity obtained from the vehicle information acquisition unit 27 is large after the short distance mode Ma is executed. S1 may be performed. In general, when the vehicle is turning, it can be assumed that the user is highly interested in objects in the short range. Therefore, by performing the processing as described above, the short distance mode Ma continues in the pulse radar device 1b while the vehicle is turning. As a result, the user can continue to check on the output unit 25 an object in the short-range range as he / she desires when turning the vehicle.

  In addition, when the state information is a shift position, the mode designating unit 111 performs step S1 when it is determined that the shift position obtained from the vehicle information acquisition unit 27 is reverse after execution of the short distance mode Ma. It doesn't matter. In general, while the vehicle is moving backward, it can be assumed that the user is highly interested in objects in the short range. Therefore, by performing the processing as described above, the short distance mode Ma continues in the pulse radar device 1b while the vehicle is turning. As a result, when the vehicle moves backward, the user can continue to confirm on the output unit 25 an object in the short-range range as desired. Similarly, the present pulse radar device 1b may be designed so that the short-distance mode Ma continues even when the shift position is low.

  By the way, in the said embodiment, as shown in FIG. 2, the timing designation | designated part 114 generates a clock for every repetition period Ta in short distance mode Ma, and also generate | occur | produces a clock for every repetition period Tb in long distance mode Mb. Was. However, the present invention is not limited to this, and a clock may be generated as described in the following third or fourth modification.

(Third Modification)
FIG. 9 is a block diagram showing a configuration of a pulse radar apparatus 1c according to the third modification of the present invention. In FIG. 9, the configuration of the pulse radar device 1 c is compared with the configuration of the pulse radar device 1 shown in FIG. 1, the control unit 11 replaces the mode specification unit 111, the timing specification unit 113, and the delay time specification unit 115. The difference is that a mode specifying unit 111c, a timing specifying unit 113c, and a delay time specifying unit 115c are included. Other than that, there is no difference in configuration between the two pulse radar apparatuses 1 and 1c. Therefore, in FIG. 9, components corresponding to those shown in FIG.

  The mode designating unit 111c generates a mode designating signal Smode as shown in FIG. 10 and outputs it to the oscillation frequency designating unit 112, the timing designating unit 113c, the pulse width designating unit 114, and the delay time designating unit 115c. The mode designation signal Smode indicates whether the pulse radar device 1 operates in the short distance mode Ma or the long distance mode Mb. In the present embodiment, the short distance mode Ma and the long distance mode Mb appear alternately. In the following description, the length of the time interval in the short distance mode Ma is Pa ′, and the length of the time interval in the long distance mode Mb is Pb ′.

  The timing designation unit 113c generates and outputs a timing signal Sclk 'that defines the transmission timing of the pulses generated by the pulse generation unit 13 in accordance with the input mode signal Smode. Specifically, the timing designating unit 113c generates a PN (Pseudo Noise) code immediately before the repetition period Ta described in the first embodiment starts during the short distance mode Ma, and based on the generated PN code. Thus, it is determined whether or not to output the clock at the current cycle Ta. For example, the timing designating unit 113c outputs a clock when the current PN code is “0”, and determines not to output a clock otherwise. In addition, during the long distance mode Mb, the timing designating unit 113c determines whether or not to output the clock at the current cycle Tb based on the PN code generated immediately before the repetition cycle Tb starts. As a result of the processing as described above, the timing signal Sclk ′ is on the time axis while the input mode signal Smode indicates the short distance mode Ma and while the long distance mode Mb indicates, as shown in FIG. Will include a random clock. The timing signal Sclk 'as described above is output to the pulse generation unit 113 and the delay time designation unit 115c.

  The delay time designating unit 115c generates a delay time designating signal Sdelay ′ for designating the amount of delay that the delay circuit 18 gives to the output signal of the modulation unit 14 in accordance with the input mode signal Smode and the input timing signal Sclk ′. Output.

  Specifically, the delay time specifying unit 115c generates one clock (see FIG. 10) when the time of i × ΔTa has elapsed after the input of the clock constituting the timing signal Sclk ′ in the short distance mode Ma. The delay circuit 18 is instructed to output the first replica pulse FRP according to such a clock. Here, i and ΔTa are determined in the same manner as in the above-described embodiment.

  Further, when the clock is given from the timing designating unit 113c in the long distance mode Mb, the delay time designating unit 115c generates one clock when the time j × ΔTb elapses after the time I × ΔTa. . The delay time specifying unit 115c instructs the delay circuit 18 to output the second replica pulse SRP according to such a clock. Here, also in this modification, j and ΔTb are determined in the same manner as in the above-described embodiment.

  The delay time designation unit 115c outputs a signal having a time waveform represented by the clock as described above as a delay time designation signal Sdelay '. The delay time designation signal Sdelay 'is also given to the detector 23 in order to designate the operation timing of the detector 23.

  As described above, since the control unit 11 has a configuration different from that of the above-described embodiment, the other elements included in the pulse radar device 1c are the same as those of the above-described embodiment in terms of configuration, but are described above in terms of processing. This embodiment is slightly different from the embodiment. Specifically, it is as follows.

  First, the pulse generator 13 generates and outputs a pulse signal PS according to the timing signal Sclk 'from the timing specification unit 113 and the pulse width specification signal Swidth from the pulse width specification unit 114. Specifically, as shown in FIG. 10, the pulse generator 13 generates a first pulse FP having a pulse width τa during the short distance mode Ma in response to a clock constituting the input timing signal Sclk ′. The second pulse SP having the pulse width τb is generated during the long distance mode Mb.

  The modulation unit 14 modulates the high frequency signal HS from the oscillator 12 with the pulse signal PS from the pulse generation unit 13 to generate and output the high frequency pulse signal PHS. As shown in FIG. 10, the time waveform of such a high-frequency pulse signal PHS includes a first high-frequency pulse FHP having a constant frequency in a time zone corresponding to the pulse width τa during the short distance mode Ma (illustrated first). The second high frequency pulse SHP (only the first one shown in the drawing) appears in the time zone corresponding to the pulse width τb during the long distance mode Mb. The high-frequency pulse signal PHS as described above is output to the HPF 15 and the delay circuit 18.

  The delay circuit 18 gives a delay amount to the inputted high frequency pulse signal PHS according to the delay time designation signal Sdelay 'outputted from the delay time designation unit 115, generates a replica pulse signal RPS of the high frequency pulse signal PHS, and generates a correlator. 22 to output.

  Specifically, the delay circuit 18 receives the first high-frequency pulse FHP (shown by a dotted line) inputted this time as soon as a clock constituting the delay time designation signal Sdelay ′ is given during the short distance mode Ma. ) Replica (hereinafter referred to as the first replica pulse) FRP (see FIG. 11) is generated and output to the correlator 22. Also, the delay circuit 18 receives a replica of the second high-frequency pulse SHP (shown by a dotted line) inputted this time as soon as a clock constituting the delay time designation signal Sdelay ′ is given during the long distance mode Mb. An SRP (referred to as a second replica pulse hereinafter) SRP (see FIG. 11) is generated and output to the correlator 22.

  Further, as described above, the high-frequency pulse signal PHS is also output to the filter 15. The high-frequency pulse signal PHS is amplified by the amplifier 16 after being removed from the unnecessary frequency component by the filter 15 and sent out from the transmitting antenna 17 to the space. In FIG. 11, the time waveform of such a high-frequency pulse signal PHS is also drawn immediately below the replica pulse signal RPS for reference.

  From the above, the correlator 22 processes the output signal (reflected pulse signal) rPS of the receiving antenna 19 using the replica pulse signal RPS generated based on the delay time designation signal Sdelay '.

By the way, although it depends on directivity, the reception antenna 19 directly receives not only the reflected pulses rPa and rPb but also the first high-frequency pulse FHP and the second high-frequency pulse SHP transmitted from the transmission antenna 17 of another radar device. It may be received. In such a case, the correlator 22 performs correlation processing on the direct wave instead of the reflected wave. Such a correlation process is not a correct process.
However, according to the present modification, the timing specifying unit 113c generates and outputs a timing specifying signal Sclk ′ composed of a random clock using the PN code in the short distance mode Ma and the long distance mode Mb. A high frequency pulse signal PHS is generated based on such a timing designation signal Sclk ′. Therefore, unlike the above-described embodiment, in the other radar apparatuses, the first high-frequency pulse FHP and the second high-frequency pulse SHP are not necessarily generated at the periods of Ta and Tb. The non-periodic first high-frequency pulse FHP and the second high-frequency pulse SHP are applied to the pulse radar device 1c, and a plurality of correlators 22 obtained by repeating the cycle Pa ′, Pb ′ or the unit cycle UC are used. By adding the results in the calculation unit 23, when there is an object, it can be assumed that the moving object is hardly moved because it is a very short time, so that the transmission high-frequency pulses FHP and SHP can be assumed. The reflected pulses rPa and pRb (reflected waves) always return after a predetermined time corresponding to the distance when the signal is transmitted, whereas the high-frequency pulses FHP and SHP transmitted from the transmitting antenna 17 of the other radar apparatus. Is not necessarily so, the reflected pulse rPa (reflected wave) and the high-frequency pulse transmitted from the transmitting antenna 17 of another radar device HP, it is possible to accurately distinguish the SHP (direct wave), it is possible not to perform the erroneous detection processing.

(Fourth modification)
FIG. 12 is a block diagram showing a configuration of a pulse radar device 1d according to a fourth modification of the present invention. In FIG. 12, the configuration of the pulse radar device 1 d is compared with the configuration of the pulse radar device 1 shown in FIG. 1, in which the control unit 11 replaces the mode specification unit 111, the timing specification unit 113, and the delay time specification unit 115. The difference is that a mode specifying unit 111d, a timing specifying unit 113d, and a delay time specifying unit 115d are included. Other than that, there is no difference in configuration between the two pulse radar apparatuses 1 and 1d. Therefore, in FIG. 12, components corresponding to those shown in FIG.

  The mode designating unit 111d generates a mode designating signal Smode as shown in FIG. 13 and outputs it to the oscillation frequency designating unit 112, the timing designating unit 113d, the pulse width designating unit 114, and the delay time designating unit 115d. The mode designation signal Smode indicates whether the pulse radar device 1 operates in the short distance mode Ma or the long distance mode Mb. In the present embodiment, the short distance mode Ma and the long distance mode Mb appear alternately. In the following description, the length of the time interval in the short distance mode Ma is Pa ″, and the length of the time interval in the long distance mode Mb is Pb ″.

  The timing designation unit 113d generates and outputs a timing signal Sclk "that defines the transmission timing of the pulses generated by the pulse generation unit 13 according to the input mode signal Smode. Specifically, the timing designation unit 113c During the mode Ma, I clocks are generated and output at different time intervals Ta1-TaI, and during the long distance mode Mb, J clocks are generated and transmitted at different time intervals Tb1-TbJ. Such a timing signal Sclk ″ is as shown in FIG. 13, and is output to the pulse generation unit 113 and the delay time designation unit 115d.

  The delay time designation unit 115d generates a delay time designation signal Sdelay "for designating the amount of delay that the delay circuit 18 gives to the output signal of the modulation unit 14 according to the input mode signal Smode and the input timing signal Sclk". Output.

  Specifically, the delay time specifying unit 115d generates one clock (see FIG. 13) when the time of i × ΔTa has elapsed after the input of the clock constituting the timing signal Sclk ″ in the short distance mode Ma. Then, the delay circuit 18 is instructed to output the first replica pulse FRP according to such a clock, where i and ΔTa are determined in the same manner as in the above-described embodiment, where I, ΔTa, and Tai The minimum value needs to satisfy the minimum value of I × ΔTa> Tai.

  Further, when the clock is given from the timing designating unit 113c in the long distance mode Mb, the delay time designating unit 115d generates one clock when the time j × ΔTb elapses after the time I × ΔTa has elapsed. . The delay time specifying unit 115d instructs the delay circuit 18 to output the second replica pulse SRP according to such a clock. Here, also in this modification, j and ΔTb are determined in the same manner as in the above-described embodiment. Note that the minimum values of J, ΔTb, and Tbi must satisfy the minimum value of I × ΔTa + J × ΔTb> Tbi.

  The delay time specifying unit 115d outputs a signal having a time waveform represented by the clock as described above as a delay time specifying signal Sdelay ". The delay time specifying signal Sdelay" indicates the operation timing of the detector 23. It is also given to the detector 23 for designation.

  As described above, since the control unit 11 has a configuration different from that of the above-described embodiment, the other elements included in the pulse radar device 1d are the same as those of the above-described embodiment in terms of configuration, but are described above in terms of processing. This embodiment is slightly different from the embodiment. Specifically, it is as follows.

  First, the pulse generator 13 generates and outputs a pulse signal PS according to the timing signal Sclk ″ from the timing specification unit 113 and the pulse width specification signal Swidth from the pulse width specification unit 114. Specifically, the pulse generation unit 13 outputs the pulse signal PS. 13 generates a first pulse FP having a pulse width τa during the short distance mode Ma in response to the clock constituting the input timing signal Sclk ″, as shown in FIG. Meanwhile, the second pulse SP having the pulse width τb is generated.

  The modulation unit 14 modulates the high frequency signal HS from the oscillator 12 with the pulse signal PS from the pulse generation unit 13 to generate and output the high frequency pulse signal PHS. As shown in FIG. 13, the time waveform of such a high-frequency pulse signal PHS includes a first high-frequency pulse FHP having a constant frequency in the time zone corresponding to the pulse width τa during the short distance mode Ma (illustrated first). The second high frequency pulse SHP (only the first one shown in the drawing) appears in the time zone corresponding to the pulse width τb during the long distance mode Mb. The high-frequency pulse signal PHS as described above is output to the HPF 15 and the delay circuit 18.

  The delay circuit 18 gives a delay amount to the inputted high frequency pulse signal PHS according to the delay time designation signal Sdelay "outputted from the delay time designation unit 115 to generate a replica pulse signal RPS of the high frequency pulse signal PHS, and a correlator. 22 to output.

  Specifically, the delay circuit 18 receives the first high-frequency pulse FHP (shown by a dotted line) inputted this time as soon as a clock constituting the delay time designation signal Sdelay "is given during the short distance mode Ma. ) FRP (referred to as the first replica pulse hereinafter) FRP (see FIG. 14) is generated and output to the correlator 22. The delay circuit 18 also delays the delay time designation signal Sdelay during the long distance mode Mb. As soon as a clock constituting "" is given, a replica (hereinafter referred to as second replica pulse) SRP of the second high-frequency pulse SHP (shown by a dotted line) inputted this time is generated and supplied to the correlator 22 Output.

  Further, as described above, the high-frequency pulse signal PHS is also output to the filter 15. The high-frequency pulse signal PHS is amplified by the amplifier 16 after being removed from the unnecessary frequency component by the filter 15 and sent out from the transmitting antenna 17 to the space. In FIG. 14, for reference, the time waveform of such a high-frequency pulse signal PHS is also drawn immediately below the replica pulse signal RPS.

  From the above, the correlator 22 processes the output signal (reflected pulse signal) rPS of the receiving antenna 19 using the replica pulse signal RPS generated based on the delay time designation signal Sdelay ″.

  As described above, according to the present modification, the timing designation unit 113d generates and outputs the timing designation signal Sclk "composed of random clocks using the PN code in the short distance mode Ma and the long distance mode Mb. The high frequency pulse signal PHS is generated based on the timing designation signal Sclk ″. Therefore, unlike the above-described embodiment, the first high-frequency pulse FHP and the second high-frequency pulse SHP are not necessarily generated at the periods of Ta and Tb. By applying the non-periodic first high-frequency pulse FHP and second high-frequency pulse SHP to the pulse radar device 1c as described above, the computing unit 23 can output the first high-frequency pulse FHP and the second high-frequency pulse SHP transmitted this time as in the third modification. It is possible to accurately distinguish one high-frequency pulse FHP (direct wave) and the reflected pulse rPa (reflected wave) of the first high-frequency pulse FHP sent last time, so that erroneous detection processing is not performed. It becomes possible.

  In the above modification, the conditions of the time intervals Tai and Tbj are that the minimum value of Tai exceeds I × ΔTa, and that the minimum value of Tbj exceeds I × ΔTa + J × ΔTb. It was. However, the present invention is not limited to this, and the time intervals Tai and Tbj may be TA + Δtai and TB + Δtbi. Here, TA is I × ΔTa, and TB is I × ΔTa + J × ΔTb. Further, Δtai and Δtbj may be freely determined.

  The pulse radar device according to the present invention can accurately detect an object existing from a short-distance region to a long-distance region, and can be applied to a vehicle-mounted application.

1 is a block diagram showing a configuration of a pulse radar device 1 according to an embodiment of the present invention. The schematic diagram which shows the signal waveform of each part in the transmission system of the pulse radar apparatus 1 shown in FIG. The schematic diagram which shows the signal waveform of each part in the receiving system of the pulse radar apparatus 1 shown in FIG. 1 is a flowchart showing the operation of the pulse radar device 1 shown in FIG. The block diagram which shows the structure of the pulse radar apparatus 1a which concerns on the 1st modification of this invention. The flowchart which shows operation | movement of the pulse radar apparatus 1a shown in FIG. The block diagram which shows the structure of the pulse radar apparatus 1b which concerns on the 2nd modification of this invention. The flowchart which shows operation | movement of the pulse radar apparatus 1b shown in FIG. The block diagram which shows the structure of the pulse radar apparatus 1c which concerns on the 3rd modification of this invention. The schematic diagram which shows the signal waveform of each part in the transmission system of the pulse radar apparatus 1c shown in FIG. The schematic diagram which shows the signal waveform of each part in the receiving system of the pulse radar apparatus 1c shown in FIG. The block diagram which shows the structure of the pulse radar apparatus 1d which concerns on the 4th modification of this invention. The schematic diagram which shows the signal waveform of each part in the transmission system of the pulse radar apparatus 1d shown in FIG. The schematic diagram which shows the signal waveform of each part in the receiving system of the pulse radar apparatus 1d shown in FIG.

Explanation of symbols

1,1a-1d pulse radar device 11 control unit 111, 111c, 111d mode designation unit 112 oscillation frequency designation unit 113, 113c, 113d timing designation unit 114 pulse width designation unit 115, 115c, 115d delay time designation unit 12 oscillator 13 pulse Generation unit 14 Modulation unit 15 Filter 16 Amplifier 17 Transmission antenna 18 Delay circuit 19 Reception antenna 20 Low noise amplifier 21 Filter 22 Correlator 23 Detector 24 Calculation unit 25 Output unit 26 Detection result storage unit 27 Vehicle information storage unit

Claims (6)

A radar device that detects a distance to a surrounding object by receiving and processing a reflected wave of a high-frequency signal transmitted by itself,
A mode designating unit for designating either the short distance mode or the long distance mode;
While the mode designating unit designates the short distance mode, the first pulse having a relatively short pulse width is repeatedly generated, and while the mode designating unit designates the long distance mode, the relatively pulse is generated. A pulse generator for generating a second pulse having a long width;
While the mode designating unit designates the short distance mode, a carrier wave having a constant frequency is generated, and while the mode designating unit designates the long distance mode, the frequency is low and high. An oscillator that generates a chirp signal swept by
While the mode designating unit designates the short distance mode, the first pulse generated by the pulse generating unit modulates the carrier wave generated by the oscillator to generate a first high frequency pulse, A modulation unit that modulates the chirp signal generated by the oscillator with the second pulse generated by the pulse generation unit to generate a second high-frequency pulse while the mode specification unit specifies the long distance mode. When,
While the mode designating unit designates the short-distance mode, the first high-frequency pulse generated by the modulation unit is transmitted to the space, and while the mode designating unit designates the long-distance mode, the modulation is performed. A radar apparatus comprising: a transmission antenna that transmits a second high-frequency pulse modulated by the unit to space. While the mode designating unit designates the short distance mode, a first replica pulse is generated based on the first high frequency pulse generated by the modulation unit, and the mode designating unit designates the long distance mode. A delay circuit for generating a second replica pulse based on the second high-frequency pulse generated by the modulation unit,
A receiving antenna that receives the first reflected pulse or the second reflected pulse reflected by the first high-frequency pulse or the second high-frequency pulse transmitted from the transmitting antenna and hitting an object;
While the mode designating unit designates the short-distance mode, the first replica pulse generated by the delay circuit and the first reflected pulse received by the receiving antenna are correlated to obtain the first. The second replica pulse generated by the delay circuit and the second reflected pulse received by the receiving antenna while the mode designating unit designates the long-distance mode A correlator that takes the correlation of and outputs a second correlation signal;
The first or second correlation signal output from the correlator is detected, and a first detection result indicating that an object is present in the short-range range, or a first result indicating that an object is present in the long-range range A detector that outputs the detection result of 2;
A calculation unit for obtaining a distance to an object based on the first or second detection result output from the detector;
An output unit that outputs information representing the distance obtained by the calculation unit to the user;
The delay circuit generates a second replica pulse in a time period corresponding to a repetition period of the first pulse generated by the pulse generator while the mode specifying unit specifies the long distance mode. The radar device according to claim 1, wherein: Information indicating whether or not an object is detected in the short distance range during the short distance mode, or information indicating whether or not an object is detected in the long distance range during the long distance mode A storage unit;
The radar apparatus according to claim 1, wherein the mode specifying unit specifies one of a short-distance mode and a long-distance mode based on information stored in the result information storage unit. A vehicle information acquisition unit that periodically acquires state information indicating the current state of the vehicle,
The radar apparatus according to claim 1, wherein the mode designating unit designates either a short distance mode or a long distance mode based on vehicle information acquired by the vehicle information acquiring unit.   2. The radar according to claim 1, wherein the pulse generation unit generates a first pulse at a first repetition period and generates a second pulse at a second repetition period longer than the first repetition period. apparatus.   The radar device according to claim 1, wherein the pulse generation unit generates the first and second pulses at random time intervals.

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