JP5284310B2 - Broadband radar apparatus and control method for broadband radar apparatus - Google Patents

Description

  The present invention relates to a broadband radar apparatus (hereinafter referred to as a radar apparatus) and a method for controlling the radar apparatus. For example, the present invention relates to a radar apparatus in which a transmission signal passes through a shield and a method for controlling the radar apparatus.

  A radar apparatus has been developed that detects a target through a shield by transmitting the transmission signal through a shield such as concrete or wood and receiving a transmission signal reflected from the target. As such a radar device, for example, there is a radar device using UWB (Ultra Wideband) (for example, Patent Document 1). The UWB radar device is used, for example, for monitoring the inside of a building through a wall from outside the building. For example, UWB radar devices can be used in crime and terrorism countermeasures and disaster relief activities.

JP 2006-194716 A

  However, the transmission characteristics of transmission signals differ depending on the material and thickness of the shield. For this reason, when the shielding objects are different, at least one of the transmission condition of the transmission signal and the reception condition of the reception signal of the radar apparatus may not be appropriate. When these conditions are set appropriately, it takes time until the radar apparatus can be used.

  An object of the present radar apparatus and radar apparatus control method is to appropriately set at least one of a transmission condition of a transmission signal and a reception condition of a reception signal.

For example, a transmission unit that transmits a transmission signal to a target through a shielding object, and a transmission signal reflected by at least the shielding object among the shielding object and the target object is transmitted as a reception signal, and then the transmission signal is transmitted. And receiving a transmission signal reflected by the shield based on a peak value of the amplitude of the received signal with respect to the time at a time in the vicinity corresponding to the reflection from the shield. When the power increases, the transmission unit transmits the transmission signal and the reception unit receives the reception signal so that at least one of the transmission power of the transmission signal and the reception gain of the reception unit decreases. A broadband radar apparatus comprising: a setting unit that sets at least one of the conditions. Is used.

For example, a transmission unit that transmits a transmission signal to a target through a shielding object, and a transmission signal reflected from at least the shielding object among the shielding object and the target object, and a time after the transmission signal is transmitted. a method of controlling a radar apparatus comprising a receiver, a receiving correspondingly, received, the peak amplitude of the received signal corresponding to the time in the time vicinity corresponding to reflection from the shield Based on this, when the reception power of the transmission signal reflected by the shield increases, the transmission unit transmits the transmission signal such that at least one of the transmission power of the transmission signal and the reception gain of the reception unit decreases. A control method for a broadband radar apparatus, comprising: a step of setting at least one of a condition for receiving and a condition for the receiving unit to receive the received signal

  According to the radar apparatus and the radar apparatus control method, it is an object to appropriately set at least one of a transmission condition of a transmission signal and a reception condition of a reception signal.

FIG. 1 is a block diagram of the radar apparatus according to the first embodiment. FIG. 2 is a diagram in which a radar device is installed on a wall as an example of a shield. FIG. 3A to FIG. 3C are diagrams showing the surface of the radar apparatus. FIG. 4 is a block diagram of the transmission unit. FIG. 5 is a block diagram of the receiving unit. FIG. 6A to FIG. 6D are diagrams for explaining equivalent time sampling. FIG. 7 is a block diagram of the AD conversion unit. FIG. 8 is a functional block diagram of the processing unit. FIG. 9 is a flowchart showing processing of the control unit. FIG. 10 is a diagram illustrating the amplitude with respect to the range of the noise level. FIG. 11 is a diagram illustrating an example of the amplitude with respect to the range of the received signal received by the receiving unit. FIG. 12A to FIG. 12D are diagrams illustrating signals that pass through the shield. FIGS. 13A to 13D are diagrams showing the amplitude of the received signal with respect to the range corresponding to FIGS. 12A to 12D. FIG. 14 is a flowchart illustrating processing of the control unit. FIG. 15 is a diagram illustrating an example of amplitude with respect to a range of a reception signal received by the reception unit. FIGS. 16A to 16D are diagrams illustrating examples of display on the operation display unit in step S40 of FIG. FIG. 17A is a diagram illustrating an example of transmission power with respect to the target distance, and FIG. 17B is a diagram illustrating an example of reception gain with respect to the target distance. FIG. 18 is a flowchart showing the processing of the control unit, and corresponds to step S22 in FIG. FIG. 19A to FIG. 19D are diagrams for explaining signal processing. FIG. 20A to FIG. 20D are diagrams illustrating an equivalent time sampling method according to the second embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a block diagram of the radar apparatus according to the first embodiment. As shown in FIG. 1, the radar apparatus 100 includes a transmission antenna 10, a reception antenna 12, a transmission unit 20, a reception unit 30, an AD conversion unit 40, a processing unit 50, a control unit 60, and an operation display unit 70. The transmission unit 20 generates a transmission signal (for example, a broadband impulse signal) and amplifies the transmission signal. The transmission unit 20 transmits a transmission signal via the transmission antenna 10. The transmission antenna 10 radiates a transmission signal into the air. The transmitted signal is transmitted through a shield such as a wall and reflected by the target. The reception antenna 12 receives a transmission signal reflected by at least the shield and the target. The receiving unit 30 receives a transmission signal received by the reception antenna 12 as a reception signal. The receiving unit 30 amplifies the received signal and down-converts it. A plurality of reception antennas 12 and reception units 30 are provided to detect the angle of the target. However, when the reception antennas are mechanically scanned, one reception antenna 12 and one reception unit 30 may be provided.

  The AD converter 40 AD (analog-digital) converts the down-converted received signal. The processing unit 50 detects the angle and distance of the target from the received signal converted into a digital signal, and tracks the target. The processing unit 50 detects the distance of the target from the time from when the transmission unit 20 transmits the transmission signal until the reception unit 30 receives the reception signal. Further, the angle of the target is detected from the time difference when the plurality of receiving units 30 receive the received signals. The operation display unit 70 displays the processing result. In addition, the operation display unit 70 transmits an operation signal to the control unit 60. The control unit 60 controls the transmission unit 20, the reception unit 30, the AD conversion unit 40, and the processing unit 50. The control unit 60 functions as a setting unit.

  FIG. 2 is a diagram in which a radar device is installed on a wall as an example of a shield. In FIG. 2, the reinforcing bar 112 in the wall 110 and the radar device 100 are seen through. As shown in FIG. 2, the wall 110 includes concrete, and a reinforcing bar 112 is provided in the concrete. Radar device 100 is brought into contact with wall 110. A plurality of reception antennas 12 and transmission antennas 10 are provided on the surface of the radar apparatus 100. Since the reinforcing bar 112 is conductive, when the reception antenna 12 is located at a position corresponding to the reinforcing bar 112, it is difficult for the reception antenna 12 to receive the transmission signal reflected from the target. Therefore, the radar apparatus 100 is installed avoiding the reinforcing bar 112.

  FIG. 3A to FIG. 3C are diagrams showing the surface of the radar apparatus. In the example of FIG. 3A, the transmission antenna 10 is provided near the center of the surface 102 of the radar apparatus 100, and four reception antennas 12 are provided on the diagonal line of the surface 102 of the radar apparatus 100. The distances L between the transmitting antenna 10 and the plurality of receiving antennas 12 are set to be approximately equal. This facilitates the calculation when the processing unit 50 calculates the angle of the target. In the example of FIG. 3B, the transmission antenna 10 is provided near the center of the surface 102 of the radar apparatus 100, and four reception antennas 12 are provided near the center of each square side of the surface 102 of the radar apparatus 100. Yes. In the case of FIG. 3B as well, the distances L between the transmitting antenna 10 and the plurality of receiving antennas 12 can be set substantially equal. In the example of FIG. 3C, a plurality of reception antennas 12 are provided at positions corresponding to the apexes of the trapezoid. As shown in FIG. 2, the reinforcing bars 112 are often provided orthogonally in the wall 110. Therefore, by shifting the positions of the plurality of reception antennas 12 from the positions corresponding to the vertices of the rectangle, it is possible to suppress the plurality of reception antennas 12 from being in positions corresponding to the reinforcing bars 112.

  FIG. 4 is a block diagram of the transmission unit. As shown in FIG. 4, the transmission unit 20 includes an impulse generator 22 and an amplifier 24. The impulse generator 22 generates an impulse signal in synchronization with the transmission timing signal received from the control unit 60. The pulse width of the impulse signal is, for example, several hundred picoseconds or less. The impulse generator 22 generates a wideband impulse signal in a band to be used from the frequency component of the impulse signal using a bandpass filter. The amplifier 24 amplifies the broadband impulse signal and transmits it as a transmission signal from the transmission antenna 10 into the air. The amplifier 24 is a variable gain amplifier and can vary the gain for amplifying the wideband impulse signal based on the level adjustment signal received from the control unit 60. Thereby, the transmission part 20 can set the electric power of a transmission signal.

  FIG. 5 is a block diagram of the receiving unit. The receiving unit 30 includes an LNA (low noise amplifier) 31, an attenuator 32, an amplifier 33, a mixer 34, a generator 35, an LPF (low pass filter) 36, an amplifier 38, and a BPF (band pass filter) 39. The LNA 31 amplifies the reception signal received by the reception antenna 12. The attenuator 32 attenuates the signal amplified by the LNA 31. The attenuator 32 is a variable attenuator and can vary the attenuation rate of the received signal based on the level adjustment signal received from the control unit 60. The amplifier 33 amplifies the received signal. The generator 35 outputs a Lo (correlation) signal in synchronization with the reception timing signal of the control unit 60. The generator 35 may be provided in common for the plurality of receiving units 30. The mixer 34 samples the received signal based on the Lo signal. The LPF 36 removes high frequency components such as harmonic components of the received signal. The amplifier 38 amplifies the received signal. The BPF 39 removes signals other than the signal in the band to be used.

  The receiving unit 30 down-converts the received signal by sampling the equivalent time, and outputs the down-converted received signal to the AD converting unit 40. By performing equivalent time sampling, the AD converter 40 for low-speed processing can be used. Thereby, the radar apparatus 100 can be reduced in size, weight, and cost. Note that the AD converter 40 capable of high-speed processing without performing equivalent time sampling may be used.

  FIG. 6A to FIG. 6D are diagrams for explaining equivalent time sampling. 6A is a timing chart of a transmission timing signal, FIG. 6B is a timing chart of a reception timing signal, FIG. 2C is a timing chart of a reception signal before equivalent time sampling, and FIG. ) Is a timing chart of a received signal after equivalent time sampling.

  As shown in FIGS. 6A and 6B, the reception timing signal is synchronized with the transmission timing signal at pulse 0. In pulse 1, the reception timing signal is delayed by Δt from the transmission timing signal. In pulse 2, the reception timing signal is delayed by 2Δt from the transmission timing signal. Thus, the reception timing signal is set to be delayed by Δt from the transmission timing signal each time the pulse increases. Thus, one sampling is performed with one pulse. For example, as shown in FIGS. 6C and 6D, the amplitude of the pulse signal at time 0 is sampled using pulse 0. Using pulse 1, the amplitude is sampled at time Δt. Using pulse 2, the amplitude is sampled at time 2Δt. In this manner, one pulse is sampled using pulses 0 to 16. Each time corresponds to the distance from the radar apparatus 100 because the transmission signal is reflected by the target and returned. Further, when digital processing is performed in the processing unit 50, time is processed as a range.

  FIG. 7 is a block diagram of the AD conversion unit. As illustrated in FIG. 7, the AD conversion unit 40 includes an AD converter 42 and a buffer 44. A plurality of AD converters 42 are provided corresponding to the receiving unit 30. Each AD converter 42 receives the reception signal down-converted by each receiving unit 30. Each AD converter 42 synchronizes with the reception timing signal received from the control unit 60 and converts the received signal into a digital signal. The buffer 44 buffers the reception signal digitally converted by each AD converter 42 and transmits it to the processing unit 50.

  FIG. 8 is a functional block diagram of the processing unit. As shown in FIG. 8, the processing unit 50 includes a buffer 51, a moving average unit 52, a moving target processing unit 59a, and a stationary target processing unit 59b. The buffer 51 buffers the reception signal received from the AD conversion unit 40. A plurality of moving average units 52 are provided corresponding to the receiving unit 30. Each moving average unit 52 performs a moving average of the received signals corresponding to each receiving unit 30. For example, a plurality of pulse signals are averaged.

  The movement target processing unit 59a detects a movement target. For example, a person who moves through the wall 110 is detected. The stationary target processing unit 59b detects a stationary target. For example, a person who is stationary through the wall 110 is detected. For example, it is detected that the person is stationary by detecting a minute movement according to breathing or the like. The movement target processing unit 59a uses STFT (Short Time Fourier Transform) processing capable of high-speed processing with reduced resolution in order to supplement moving people and the like. On the other hand, the stationary target processing unit 59b uses a low-speed but high-resolution FFT (Fast Fourier Transform) process in order to make a stationary person thin.

  The movement target processing unit 59a includes an STFT unit 53, a CFAR (Constant False Alarm Ratio) unit 55, a target range detection unit 56, an angle measurement unit 57, and an information output unit 58. A plurality of STFT units 53, CFAR units 55, and target range detection units 56 are provided corresponding to the reception unit 30. The STFT unit 53 uses a plurality of pulses (for example, 8) and performs Fourier transform on the amplitude of the received signal for each range. The maximum amplitude after Fourier transform in each range is defined as the amplitude of each range. The CFAR unit 55 performs CFAR processing. The CFAR process is a process for extracting a range having a larger amplitude than the preceding and following ranges. The target range detection unit 56 detects the distance from the extracted range to the target. The angle measuring unit 57 calculates the angle of the target from the distance to the target corresponding to the plurality of received signals. The information output unit 58 outputs information on the distance to the target and the angle on the operation display unit 70.

  The stationary target processing unit 59b is the same as the movement target processing unit 59a except that the STFT unit 53 is replaced with an FFT unit 54. The FFT unit 54 performs Fourier transform on the amplitude of the received signal for each range using a larger number of pulses (for example, 256) than the STFT unit 53. Other configurations are the same as those of the movement target processing unit 59a, and a description thereof will be omitted.

  FIG. 9 is a flowchart showing processing of the control unit. The control unit 60 observes the attenuation characteristics of a shield such as a wall, and automatically sets the radar apparatus 100 from the observation data. As a premise when the control unit 60 performs the setting, when the radar apparatus 100 transmits and receives a pulse signal in a state where there is no obstacle such as a wall, an RCS (Rader) of an assumed target (for example, a human) is assumed. In Cross Section, the radar apparatus 100 is set so that the receiving unit 30 is not saturated. For example, the transmission power transmitted by the transmission unit 20 and the gain of the reception unit 30 are appropriately set. In this state, the radar apparatus 100 is installed at a place of use (for example, facing a shield such as a wall).

  Referring to FIG. 9, the control unit 60 acquires a noise level specific to the radar apparatus 100 (step S10). For example, the control unit 60 corresponds to each reception unit 30 and acquires the amplitude of the reception signal with respect to the range for a predetermined time (for example, several seconds) without transmitting the transmission signal. FIG. 10 is a diagram illustrating the amplitude with respect to the range of the noise level. As shown in FIG. 10, the average noise level is defined as the off power Roff. The off power Roff can be the maximum power within a predetermined time in addition to the time average of the noise level.

  Next, the control unit 60 causes the transmission unit 20 to transmit a transmission signal (step S12). For example, the transmission unit 20 transmits an impulse signal having a predetermined interval as a transmission signal for several seconds. Next, the control part 60 makes each receiving part 30 receive a received signal (step S14). FIG. 11 is a diagram illustrating an example of the amplitude with respect to the range of the received signal received by the receiving unit 30. As shown in FIG. 11, the amplitude in the vicinity of 0 in the range (time near 0) is large, and the range in the vicinity of 0 is a signal reflected near the radar apparatus 100 and a signal reflected by the shielding object.

  Based on the received signal, the control unit 60 determines whether the transmission signal is transmitted through the shield (step S16). In the case of No, the operator is notified that the transmission signal does not pass through the shield (step S18). The operator changes the installation location of the radar apparatus 100 and the like. Return to step S10. In the case of Yes in step S16, the control unit 60 is based on the received signal. At least one of a condition for the transmission unit 20 to transmit a transmission signal and a condition for the reception unit 30 to receive a reception signal is set (step S20). The controller 60 sets a CFAR minimum threshold (step S22). The control unit 60 starts operation of the radar apparatus 100 (step S24). The control unit 60 determines whether the mode of the radar apparatus 100 has been changed during operation of the radar apparatus 100 (step S26). If no, the process ends. If Yes, the process returns to step S22, and the CFAR minimum threshold is reset (step S22).

  Next, an example of processing in steps S16 and S20 in FIG. 9 will be described. FIG. 12A to FIG. 12D are diagrams illustrating signals that pass through the shield. FIGS. 13A to 13D are diagrams showing the amplitude of the received signal with respect to the range corresponding to FIGS. 12A to 12D. 13A to 13D illustrate the range corresponding to the time after the transmission antenna 10 outputs the transmission signal. On the other hand, FIG. 11 shows the range from the peak of the received signal (corresponding to the opposite surface of the wall to the radar device 100).

  As shown in FIG. 12A, in the case of the metal wall 114, almost all the transmission signal is reflected by the metal wall 114. For this reason, the peak amplitude of the received signal becomes large as shown in FIG. As shown in FIG. 12B, when the non-metallic wall 110 is thin, the transmission signal is mainly reflected on the surface 116 of the wall 110 opposite to the radar device 100. For this reason, the signal absorbed by the wall 110 is small. Part of the transmitted signal passes through the wall 110. As shown in FIG. 13B, the peak amplitude of the received signal is relatively smaller than that shown in FIG. 13A, but is larger than those shown in FIGS. 13C and 13D described later. As shown in FIGS. 12C and 12D, the transmission signal is mainly reflected by the surface 116. The signal absorbed by the wall 110 increases as the wall 110 becomes thicker. As shown in FIGS. 13C and 13D, the peak amplitude of the received signal decreases as the wall 110 becomes thicker.

  FIG. 14 is a flowchart illustrating processing of the control unit. The following processing can also be performed for each receiving unit 30. The control unit 60 analyzes the received signal received in step S14 of FIG. 9 (step S30). For example, data in the vicinity of the received signal corresponding to reflection from the wall 110 is cut out. The amplitude peak value of the received signal is extracted from the extracted data. The cut out data is, for example, data as shown in FIG. 13 (a) to FIG. 13 (d). As shown in FIGS. 13A to 13D, the peak value Pn of the amplitude is extracted. A large peak value Pn indicates that the signal attenuation by the wall 110 is small. In addition, the peak position substantially corresponds to the position of the surface 116.

  The control unit 60 determines whether or not the peak value Pn is greater than or equal to the threshold value A (step S32). In No, the control part 60 judges whether the peak value Pn is more than threshold value A1 (step S34). In the case of No, the control unit 60 further determines whether it is greater than or equal to the threshold value A2. In this way, the control unit 60 sequentially determines whether the peak value Pn is greater than or equal to the threshold values A2 to An-1. Finally, the control unit 60 determines whether the peak value Pn is greater than or equal to the threshold value An (step S36). The thresholds A to An are values that become smaller in order as shown in FIG. 13 (a) to FIG. 13 (d). In the case of FIG. 13A, since the peak value Pn is equal to or greater than the threshold value A, it is determined Yes in step S32. In the case of FIG. 13B, the peak value Pn is smaller than the threshold value A and greater than or equal to the threshold value A1, and therefore it is determined Yes in step S32. In the case of FIG. 13C, the peak value Pn is smaller than the threshold value An−1 and is equal to or larger than the threshold value An, and therefore, “Yes” is determined in step S34. In the case of FIG. 13D, since the peak value Pn is smaller than the threshold value An, it is determined No in step S36. Thus, the cases are classified based on the magnitude of the peak value Pn.

  In the case of Yes in steps S32 to S36 and in the case of No in step S36, the control unit 60 determines whether or not the received power Rf beyond the vicinity is equal to or less than the threshold B (step S38). FIG. 15 is a diagram illustrating an example of amplitude with respect to a range of a reception signal received by the reception unit. As shown in FIG. 15, the average of the received power of the reflected signal beyond the vicinity is defined as the received power Rf. When the received power Rf is smaller than the threshold value B, there is almost no signal reflected from beyond the vicinity. That is, there is a strong possibility that the transmission signal does not pass through the shield. Therefore, in the case of Yes in step S38, the control unit 60 notifies the operator that the transmission signal does not pass through the shield (step S40). Step S38 corresponds to step S16 in FIG. 9, and step S40 corresponds to step S18 in FIG. In the case of No in step S38, the control unit 60 determines that there is nothing that inhibits transmission signal transmission like metal (step S42). As the threshold B, for example, the off power Roff acquired in step S10 of FIG. 9 can be used. Alternatively, the threshold value B can be set to a value sufficiently larger than the off power Roff. For example, the threshold B can be a value obtained by adding a certain amount to the off power Roff, or a value obtained by multiplying the off power Roff by a certain amount greater than 1.

  FIGS. 16A to 16D are diagrams illustrating examples of display on the operation display unit in step S40 of FIG. FIG. 16A shows a screen 72 of the operation display unit 70. Images in FIGS. 16B to 16D are displayed in an area 74 in the screen 72. As shown in FIG. 16B to FIG. 16C, the color of the reception antenna 12 in the reception antenna 12 in the radar apparatus 100 from which the reception signal farther from the vicinity cannot be obtained is changed (FIG. 12B). From FIG. 12 (d), it is shown as a cross). In FIG. 12B, the reception antennas 12 other than the lower left cannot obtain a reception signal. In FIG. 12C, all the reception antennas 12 cannot obtain the reception signal. Thereby, it is thought that the reinforcing bar 112 is provided in the shield as indicated by the dotted lines in FIGS. 12 (b) and 12 (c). Therefore, the operator changes the position of the radar apparatus 100. As a result, as shown in FIG. 12D, all reception antennas 12 can obtain reception signals. In this way, the operator can recognize the reception antenna 12 from which a reception signal cannot be obtained.

  In FIG. 14, the control unit 60 determines at least one of a condition for the transmission unit 20 to transmit a transmission signal and a condition for the reception unit 30 to receive a reception signal according to the magnitude of reception power in the vicinity (for example, the peak value Pn). Is set (step S44). FIG. 17A is a diagram illustrating an example of transmission power with respect to the distance of the target, and FIG. 17B is a diagram illustrating an example of reception gain with respect to the distance of the target. As shown in FIG. 17A, the transmission power is set to increase as the distance from the target increases. The reason why the transmission power is saturated in the region where the distance is long is that the transmission power becomes maximum. As shown in FIG. 17B, the reception gain is set to increase as the distance to the target increases. The reason why the reception gain is saturated in the region where the distance is long is that the reception gain is maximized. In the case of Yes in step S32 of FIG. 14 (when the reception power in the vicinity is greater than or equal to the threshold A), the control unit 60 sets the transmission power and the reception gain to setting 1. In the case of Yes in step S34 of FIG. 14 (when the reception power in the vicinity is smaller than the threshold value A1 and greater than or equal to A2), the control unit 60 sets the transmission power and the reception gain to setting 2. In the case of No in step S36 of FIG. 14 (when the reception power in the vicinity is smaller than the threshold value An), the control unit 60 sets the transmission power and the reception gain to the setting n.

  As described above, the control unit 60 sets the transmission power so that the transmission power decreases when the reception power of the transmission signal reflected by the shielding object increases. In addition, the control unit 60 sets the reception gain so that the reception gain decreases when the reception power of the transmission signal reflected by the shield increases. Thereby, when the attenuation by the shield is small, it is possible to suppress saturation of the reception signal by reducing the transmission power and the reception gain. On the other hand, when the attenuation by the shield is large, the loss due to the shield of the signal can be compensated by increasing the transmission power and the reception gain. The reception gain can be changed by changing the attenuation factor of the attenuator 32 of the receiving unit 30 in FIG. It can also be performed by changing the amplification factor of the amplifier of the receiving unit 30. Further, the reception gain can be changed for each receiving unit 30.

  FIG. 18 is a flowchart showing the processing of the control unit, and corresponds to step S22 in FIG. FIG. 19A to FIG. 19D are diagrams for explaining signal processing. As illustrated in FIG. 18, the control unit 60 causes the transmission unit 20 to transmit a transmission signal and causes the reception unit 30 to receive the reception signal (step S50). FIG. 19A is a diagram illustrating the amplitude with respect to the range of the received signal. The controller 60 performs an averaging process after the STFT or FFT process (step S52). FIG. 19B is a diagram of amplitude with respect to the range after STFT processing. FIG. 19C is a diagram of the amplitude with respect to the range after the averaging process. The control unit 60 obtains the amplitude distribution of FIG. 19C (step S54). FIG. 19D is a diagram in which the amplitude distribution of FIG. 19C is obtained. In FIG. 19D, the control unit 60 sets the CFAR minimum threshold based on the peak value of the amplitude frequency (step S56). For example, in FIG. 19D, n times the peak value is the CFAR minimum threshold Th. As shown in FIG. 19C, the CFAR minimum threshold Th is set. Step S22 in FIG. 9 ends. In this manner, the CFAR minimum threshold is set based on the peak of the distribution of the amplitude of the received signal with respect to the distance (range) to the target. Thereby, it is possible to suppress detection of a target due to fluctuations in the amplitude of the noise level during the CFAR process.

  According to the first embodiment, as in step S20 of FIG. 9, the condition in which the control unit 60 (setting unit) transmits the transmission signal based on the reception signal and the condition in which the reception unit 30 receives the reception signal. Set at least one of Thereby, at least one of the transmission condition of the transmission unit 20 and the reception condition of the reception unit 30 can be appropriately set according to the electrical property of the shield.

  For example, as illustrated in FIG. 17A, the control unit 60 can set the transmission power of the transmission signal based on the reception power of the transmission signal reflected by the shield. Further, the control unit 60 can set the gain of the reception signal based on the reception power of the transmission signal reflected by the shield.

  Further, as in step S38 of FIG. 15, the control unit 60 can determine whether or not the transmission signal is transmitted through the shield based on the received power of the pulse signal reflected beyond the shield. Thereby, the operator can install the radar apparatus 100 appropriately. For example, the control unit 60 can determine that the transmission signal does not pass through the shielding object when the reception power of the transmission signal reflected beyond the shielding object is smaller than the threshold value.

  Further, as in step S56 of FIG. 18, the control unit 60 can set the amplitude larger than the peak of the amplitude distribution of the received signal with respect to the distance to the target as the CFAR minimum threshold. During the CFAR process, it is possible to suppress the detection of the target due to the vibration of the amplitude of the noise level.

  FIG. 20A to FIG. 20D are diagrams illustrating an equivalent time sampling method according to the second embodiment. As shown in FIG. 20B, the reception timing signal is synchronized with the transmission timing signal from pulse 0 to pulse 2. In the pulse 3 to the pulse 6, the reception timing signal is delayed by a time Δt from the transmission timing signal. As shown in FIGS. 20C and 20D, the sampled amplitudes from pulse 0 to pulse 3 are averaged to obtain an amplitude at time 0. FIG. The sampled amplitudes from pulse 4 to pulse 6 are averaged to obtain the amplitude at time Δt. As described above, when the reception unit 30 performs the equivalent time sampling of the reception signal, the reception unit 30 performs sampling a plurality of times continuously at the same sampling point. Thereby, the movement of the target in a sampling interval can be made small. Therefore, the S / N ratio can be improved.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Transmission antenna 12 Reception antenna 20 Transmission part 30 Reception part 40 AD conversion part 50 Processing part 60 Control part

Claims (8)

A transmission unit that transmits the transmission signal to the target through the shield,
A receiving unit that receives a transmission signal reflected by at least the shielding object among the shielding object and the target object as a reception signal and corresponding to a time after transmitting the transmission signal;
Based on the peak value of the amplitude of the received signal with respect to the time in the vicinity of the time corresponding to the reflection from the shielding object, when the reception power of the transmission signal reflected on the shielding object increases, the transmission power of the transmission signal A setting unit that sets at least one of a condition for the transmission unit to transmit the transmission signal and a condition for the reception unit to receive the reception signal so that at least one of the reception gain of the reception unit is small ;
A broadband radar apparatus comprising: The setting unit may change the peak value of the amplitude of the received signal corresponding to the time, using a plurality of pulses, based on the peak value that the amplitude Fourier transform of the received signal corresponding to the time, the shield The transmission unit transmits the transmission signal and the reception so that at least one of the transmission power of the transmission signal and the reception gain of the reception unit decreases when the reception power of the transmission signal reflected in 2. The broadband radar apparatus according to claim 1, wherein the unit sets at least one of the conditions for receiving the received signal. The broadband according to claim 1 or 2 , wherein the setting unit determines whether or not the transmission signal is transmitted through the shield based on reception power of a transmission signal reflected beyond the shield. Radar device. 4. The broadband according to claim 3 , wherein the setting unit determines that the transmission signal does not pass through the shielding object when the reception power of the transmission signal reflected beyond the shielding object is smaller than a threshold value. Radar device. The setting unit includes Wideband radar according to any one of claims 1 to 4, characterized in that the said target and said received signal amplitude large amplitude minimum threshold of CFAR than the peak of the distribution of relative distances apparatus. The receiving unit, when the equivalent time sampling the received signal, the wideband radar apparatus according to any one claim of succession in the same sampling point from claim 1, characterized in that a plurality of times sampling 5. A transmission unit that transmits the transmission signal to the target through the shielding object, and a transmission signal reflected by at least the shielding object among the shielding object and the target object, corresponding to the time after the transmission signal is transmitted In a method for controlling a radar apparatus comprising:
Based on the peak value of the amplitude of the received signal corresponding to the time in the vicinity of the time corresponding to the reflection from the shield, the transmission power is increased when the reception power of the transmission signal reflected by the shield is increased. At least one of a condition for the transmission unit to transmit the transmission signal and a condition for the reception unit to receive the reception signal is set so that at least one of the transmission power of the signal and the reception gain of the reception unit becomes small A control method for a broadband radar apparatus, comprising a step. Step condition and the receiving portion and the transmitting portion transmits the transmission signal to set at least one of the conditions for receiving the reception signal, instead of the peak value of the amplitude of the received signal corresponding to the time, more When the reception power of the transmission signal reflected by the shield increases based on the peak value obtained by Fourier transforming the amplitude of the reception signal corresponding to the time, the transmission power of the transmission signal and the reception unit 8. The method for controlling a broadband radar apparatus according to claim 7 , wherein at least one of the reception gain is set to be small .

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