JP2009258133A - Pulse radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfy both the high detection accuracy and the quick detection in a faraway place in computing a relative distance or a relative speed to an object in a pulse radar system. <P>SOLUTION: This pulse radar system includes a transmission means for transmitting pulsed radio waves and a receiving means for receiving reflection wave of transmitted radio waves by the transmission means, wherein a relative distance or a relative speed to an object is computed based on the relationship between the radio wave transmission of the transmission means and the radio wave receiving of the receiving means. Among range bins obtained by dividing a detection range for which a relative distance or a relative speed to an object is computed into a predetermined number, a presence range bin where an object exists is detected, and when the presence range bin is detected, hereinafter the pulse duration of a radio wave transmitted by the transmission means concerning the presence range bin is reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pulse radar device, and in particular, by transmitting a pulsed radio wave and receiving a reflected wave obtained by reflecting the transmitted radio wave on an object, the relative distance or relative to the object is obtained. The present invention relates to a pulse radar device suitable for detecting speed.

  Conventionally, the presence of an object is determined based on the relationship between the radio wave transmission and radio wave reception by transmitting a pulsed radio wave and receiving the reflected wave obtained by reflecting the transmitted radio wave on the object. A pulse radar device that calculates a relative distance or a relative speed with respect to an object is known (see, for example, Patent Document 1).

JP 2003-329964 A

  By the way, as the pulse width of the transmission radio wave is shorter, the detection accuracy of the distance to the object can be improved. However, it becomes difficult to make the distance detection immediately compatible with the medium / long distance, and the medium / long It takes a lot of time to deal with the distance. On the other hand, if the pulse width of the transmission radio wave is long, it is easy to perform distance detection corresponding to medium / long distance immediately, but the distance detection accuracy decreases.

  However, in the above-described pulse radar device described in Patent Document 1, the pulse width of the transmission radio wave is fixed, and is not varied according to the position of the detection range where the detection of the object is required. In this respect, in the above pulse radar device, it is difficult to achieve both rapid detection and high detection accuracy in calculating the relative distance or relative speed with respect to the object.

  The present invention has been made in view of the above points, and a pulse radar device capable of achieving both rapid detection and high detection accuracy in calculating the relative distance or relative speed with respect to an object. The purpose is to provide.

  The above object includes a transmission means for transmitting a pulsed radio wave and a reception means for receiving a reflected wave of the transmission radio wave by the transmission means. The radio wave transmission by the transmission means and the radio wave reception by the reception means A pulse radar device that calculates a relative distance or relative speed with respect to an object based on a relationship, wherein a target is selected from a range bin in which a detection range for calculating the relative distance or relative speed with respect to the object is divided into a predetermined number When the presence range bin is detected by the presence range bin detection unit that detects the presence range bin in which an object is present, and thereafter, the pulse width of the radio wave transmitted by the transmission unit is shortened for the presence range bin. And a pulse width shortening unit.

  In the invention of this aspect, when an existing range bin in which an object is present is detected from a range bin in which a detection range in which a relative distance or relative speed with respect to the object is to be calculated is divided into a predetermined number, transmission is performed for the existing range bin. The pulse width of the radio wave is shortened. If the pulse width of the transmitted radio wave is shortened, the resolution for detecting the object increases. Therefore, compared to when the pulse width is long before that, the presence range bin in which the object is detected is detected. It is possible to improve the detection accuracy of the object, and on the other hand, since the pulse width is relatively long before the pulse width is shortened, the object can be detected quickly within the entire detection range including far away. Is possible. Therefore, according to the present invention, it is possible to achieve both high detection accuracy and quick detection at a distance when calculating the relative distance or relative speed with respect to the object.

  Further, the above object is provided with a transmission means for transmitting a pulsed radio wave and a reception means for receiving a reflected wave of the transmission radio wave by the transmission means, the radio wave transmission by the transmission means and the radio wave reception by the reception means. A pulse radar device that calculates a relative distance or relative speed with respect to an object based on the relationship between the target and a range bin in which a detection range in which the relative distance or relative speed with respect to the object is to be calculated is divided into a plurality of ranges A presence range bin detecting means for detecting a presence range bin in which an object is present; and when the presence range bin is detected by the presence range bin detection means, a relative distance or relative to an object among all range bins in the detection range One or more range bins that include the existing range bin and one or more existing range bins that are required to calculate the speed are present at the end of the detection range. A calculation-requiring range bins limited means to limit the range bins is achieved by a pulse radar apparatus provided with.

  In the invention of this aspect, when an existing range bin in which the object is present is detected from among the range bins in which the detection range for calculating the relative distance or relative speed with respect to the object is divided into a plurality of detection ranges, thereafter, all of the detection ranges within the detection range are detected. Of the range bins, the required range bins for calculating the relative distance or relative speed with respect to the object are limited to one or more range bins including the existing range bin and one or more range bins present at the end of the detection range. If the calculation range bins are limited, it becomes possible to quickly detect an object within the detection range, compared to those in which the limitation is not made, and it is possible to cope with a relatively short pulse width of the transmission radio wave. It becomes possible. Therefore, according to the present invention, it is possible to achieve both high detection accuracy and quick detection at a distance when calculating the relative distance or relative speed with respect to the object.

  In the pulse radar apparatus described above, the calculation required range bin may be initially only a range bin existing at the end of the detection range.

  And a transmission means for transmitting a pulsed radio wave and a reception means for receiving a reflected wave of the transmission radio wave by the transmission means, based on a relationship between radio wave transmission by the transmission means and radio wave reception by the reception means. A pulse radar device that calculates the relative distance or relative speed with the target object, and the target exists among the range bins that divide the detection range into which the relative distance or relative speed with the target should be calculated. Presence range bin detection means for detecting a range bin, and when the existence range bin is detected by the presence range bin detection means, the received radio wave necessary for calculating the relative distance or relative speed of the presence range bin with the object is calculated. A pulse radar apparatus comprising an integration number increasing means for increasing the number of integration processes improves the SN ratio and increases the detection sensitivity. It is effective.

  In the invention of this aspect, when a presence range bin in which the target exists is detected from among the range bins in which the detection range in which the relative distance or relative speed with the target is to be calculated is divided into a plurality of detection ranges, The number of integration processes is increased. If the number of times of integration processing of received radio waves increases, the S / N ratio is improved, and the sensitivity for calculating the relative distance or relative speed with respect to the object increases. Therefore, according to the present invention, it is possible to improve the SN ratio and increase the detection sensitivity when calculating the relative distance or relative speed with the object.

  In the pulse radar device described above, pulse width varying means for varying the pulse width of the radio wave transmitted by the transmitting means in accordance with the position of the required detection range where the calculation of the relative distance or relative speed with the object is required. It is good also as providing.

  In the invention of this aspect, the pulse width of the radio wave transmitted by the transmission means is varied according to the position of the required detection range where the calculation of the relative distance or relative speed with the object is required. In such a configuration, if the pulse width is shortened when computation with a relatively near object is required, the resolution for detecting the object increases, so the detection accuracy of the relatively near object is increased. In addition, it is possible to detect a relatively distant object quickly by increasing the pulse width when computation with a relatively distant object is required. Therefore, according to the present invention, in calculating the relative distance or relative speed with respect to the object, it is possible to achieve both high detection accuracy in the near field and quick detection in the far field.

  In this case, the pulse width varying means shortens the pulse width as the position of the required detection range is closer, while increasing the pulse width as the position of the required detection range is farther. do it.

  According to the present invention, it is possible to achieve both high detection accuracy and quick detection at a distance when calculating the relative distance or relative speed with respect to the object.

1 is a configuration diagram of a pulse radar device according to a first embodiment of the present invention. It is the figure which each showed the mounting location of the transmission / reception antenna as a radar sensor with which the pulse radar apparatus of a present Example is equipped, the detection range, and the pulse width of a transmission radio wave. It is a figure for demonstrating the method to detect the distance from the own mobile body to a target in a present Example. It is a figure for demonstrating the method to detect the relative velocity of the target with respect to a self-moving body in a present Example. It is a figure for demonstrating the method to detect the angle position of the target with respect to a self-moving body in a present Example. It is a figure showing the operation | movement sequence of the pulse radar apparatus of a present Example. It is a flowchart of an example of the control routine performed in the pulse radar apparatus of a present Example. It is a figure for demonstrating the characteristic operation | movement in the pulse radar apparatus of a present Example. It is a figure for demonstrating the characteristic operation | movement in the pulse radar apparatus of a present Example. It is a flowchart of an example of the control routine performed in the pulse radar apparatus which is 2nd Example of this invention. It is a figure for demonstrating the characteristic operation | movement in the pulse radar apparatus of a present Example. It is a flowchart of an example of the control routine performed in the pulse radar apparatus which is 3rd Example of this invention. It is a figure for demonstrating the characteristic operation | movement in the pulse radar apparatus of a present Example. It is a flowchart of an example of the control routine performed in the pulse radar apparatus which is 4th Example of this invention. It is a figure for demonstrating the characteristic operation | movement in the pulse radar apparatus of a present Example. It is a block diagram of the pulse radar apparatus which is a modification of this invention. It is a block diagram of the pulse radar apparatus which is a modification of this invention.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a pulse radar device 20 according to an embodiment of the present invention. Also, FIG. 2 shows a place where a transmission / reception antenna as a radar sensor included in the pulse radar apparatus 20 of this embodiment is mounted (FIG. (A)), a detection range (FIG. (B)), and a pulse width ( The figure which each represented (C) of the figure is shown.

  The pulse radar device 20 of this embodiment is mounted on a moving body such as a vehicle, and transmits and receives pulsed radio waves toward a predetermined detection range such as forward and backward with respect to the moving body. This is a device for detecting an object (target) existing around the moving body. The moving body on which the pulse radar device 20 is mounted is not limited to a vehicle that moves on land, such as a vehicle, but may be a flying object that moves in the air.

  As shown in FIG. 1, the pulse radar device 20 includes a transmission circuit 22. The transmission circuit 22 includes a continuous wave source 24, a pulse formation unit 26, an amplifier 28, and a transmission antenna 30.

  The continuous wave source 24 continuously generates a high-frequency signal without interruption. The pulse forming unit 26 has a switch for switching between passing and blocking of the signal generated by the continuous wave source 24, and a pulse-modulated pulse signal having a predetermined pulse width at a predetermined cycle is turned on / off by the switch. Generate repeatedly. The amplifier 28 amplifies the pulse signal generated by the pulse forming unit 26. The transmission antenna 30 (Tx) radiates the pulse signal amplified by the amplifier 28 to the external space as a transmission radio wave.

  Radiation of the pulse signal from the transmitting antenna 30 is performed mainly in the moving direction of the own moving body, and is performed so that a predetermined detection range is formed in this direction (FIG. 2B). Further, this radiation may be performed so that a relatively narrow radiation beam is scanned over the entire detection range, or a plurality of transmission antennas 30 having different radiation directions may be provided to widen the detection range.

  The transmission period (pulse repetition frequency) T of the pulse signal from the transmission circuit 22 is T> 2 · Dmax / c, where Dmax is the maximum distance from the moving body to the target to be detected and c is the speed of light. Is set as follows. The pulse width (shown in FIG. 2C) W of the pulse signal from the transmission circuit 22 corresponds to the minimum distance (distance resolution: range bin) that can be separated as the distance to the target. When the distance is A and the speed of light is c, the relationship of W = 2 · A / c is established.

  The pulse radar device 20 also includes two receiving circuits 32 and 34 having substantially the same characteristics. The reception circuit 32 includes a reception antenna 36 (Rx1), an amplifier 38, two mixers 40 and 42, two integration circuits 44 and 46, two switches 48 and 50, and two AD conversion units 52 and 54. And have. The reception circuit 34 also includes a reception antenna 56 (Rx2), an amplifier 58, two mixers 60 and 62, two integration circuits 64 and 66, two switches 68 and 70, and two AD conversion units 72. , 74. The two receiving antennas 36 and 56 are arranged apart from each other by a predetermined distance d in the horizontal direction of the mobile body (for example, in the vehicle width direction in the case of a vehicle).

  As shown in FIG. 2A, the transmitting antenna 30 and the two receiving antennas 36 and 56 are arranged at the front, rear, side, upper, or lower part of the vehicle if the moving body is a vehicle. Installed in bumpers, front lights, rear lamps, pillars, mirrors, doors, etc.

  Each of the receiving antennas 36 and 56 receives the pulsed reflected wave when the pulsed transmitting radio wave transmitted from the transmitting antenna 30 is reflected by the target. The reception pulse received by the reception antenna 36 is amplified by the amplifier 38 and then supplied to both the mixers 40 and 42. The received pulse received by the receiving antenna 56 is amplified by the amplifier 58 and then supplied to both the mixers 60 and 62.

  The continuous wave source 24 is connected to the inputs of the mixers 40 and 42 through the switch 76 as well as the amplifier 38. The continuous wave source 24 is connected not only to the amplifier 58 but also to the inputs of the mixers 60 and 62 via the switch 76. The switch 76 is a switch that is turned on after a predetermined time delay from the switch-on in the pulse forming unit 26, that is, the transmission of the transmission pulse from the transmission antenna 30 of the transmission circuit 22.

  Both the mixers 40 and 42 receive the output of the amplifier 38 (= reception pulse) and a local pulse delayed by a predetermined time from the transmission pulse. The phase of the local pulse input to the mixer 42 is shifted (delayed) by + 90 ° with respect to the local pulse input to the mixer 40. Further, both the mixers 60 and 62 are supplied with the output of the amplifier 58 (= received pulse) and with a local pulse delayed by a predetermined time from the transmitted pulse. The phase of the local pulse input to the mixer 62 is shifted (delayed) by + 90 ° with respect to the local pulse input to the mixer 60.

  The local pulse described above is repeatedly generated while appropriately changing the delay time from transmission of the transmission pulse. The delay time is changed corresponding to each of the range bins obtained by dividing the maximum distance Dmax (detection range) from the moving object to the target to be detected into a plurality (for example, 100). The mixers 40, 42, 60, and 62 each mix and output the received pulse and the local pulse.

  An integrating circuit 44 is connected to the mixer 40, an integrating circuit 46 is connected to the mixer 42, an integrating circuit 64 is connected to the mixer 60, and an integrating circuit 66 is connected to the mixer 62. The integration circuits 44, 46, 64, and 66 respectively integrate the outputs of the mixers 40, 42, 60, and 62. Specifically, the integration circuits 44, 46, 64, and 66 perform a predetermined plurality of times (for example, 10 times) of transmission pulses for each pulse repetition frequency T. Accumulate the mixer output for transmission.

  The integrating circuit 44 has an AD converter 52 via a switch 48, the integrating circuit 46 has an AD converter 54 via a switch 50, the integrating circuit 64 has an AD converter 72 via a switch 68, An AD converter 74 is connected to the integrating circuit 66 via a switch 70. The AD converters 52, 54, 72, and 74 convert the outputs of the integrating circuits 44, 46, 64, and 66 into digital signals when the switches 48, 50, 68, and 70 are on, respectively.

  The pulse radar device 20 also includes a control circuit 80. The control circuit 80 is connected to the pulse forming unit 26 and the switches 48, 50, 68, 70, and 76 via a control line. The control circuit 80 controls the switch of the pulse forming unit 26 so that a transmission pulse having a predetermined pulse width W is radiated from the transmission antenna 30 to the outside at a predetermined pulse repetition frequency T, and transmits from the transmission antenna 30. The switch 76 is controlled so that a local pulse is generated with a predetermined time delay from the pulse emission and input to the mixers 40, 42, 60, 62.

  The control circuit 80 is also connected to the AD conversion units 52, 54, 72 and 74. The control circuit 80 is supplied with each digital output of the AD converters 52, 54, 72 and 74. Based on the digital output values of the AD conversion units 52, 54, 72, and 74 when the switches 48, 50, 68, and 70 are turned on, the control circuit 80, as will be described in detail later, from the own moving body to the target. , The relative speed of the target with respect to the moving body, and the angular position of the target with respect to the moving body. Then, the detection result of the target is output to the outside.

  Next, the basic operation of the pulse radar apparatus 20 of the present embodiment will be described with reference to FIGS. FIG. 3 is a diagram for explaining a method of detecting the distance from the moving body to the target in the present embodiment. FIG. 4 is a diagram for explaining a method of detecting the relative speed of the target with respect to the moving body in the present embodiment. FIG. 5 is a diagram for explaining a method of detecting the angular position of the target with respect to the moving body in the present embodiment. Moreover, FIG. 6 shows the figure showing the operation | movement sequence of the pulse radar apparatus 20 of a present Example. FIG. 6 shows a case where the number of range bins in the detection range is “4” and the number of receptions that should be continuously received in the same range bin is “3”.

  In the present embodiment, when a moving body equipped with the pulse radar device 20 is activated, the continuous wave source 24 of the pulse radar device 20 generates a continuous wave during the activation thereafter. The control circuit 80 controls the switch of the pulse forming unit 26 so that a transmission pulse is externally radiated from the transmission antenna 30 at a predetermined pulse repetition frequency T during generation of a continuous wave by the continuous wave source 24. In this case, a transmission pulse is radiated to the outside from the transmission antenna 30 at a predetermined pulse repetition frequency T.

  The transmission pulse radiated from the transmission antenna 30 is not reflected when the target does not exist within the detection range of the maximum distance Dmax to the target to be detected. In this case, the reflected wave of the transmission pulse is not received by the receiving antennas 36 and 56. On the other hand, the transmission pulse radiated from the transmission antenna 30 is reflected by the target when the target exists within the detection range. In this case, the reflected wave of the transmission pulse is received by the receiving antennas 36 and 56. When the reflected wave of the transmission pulse is received by the reception antennas 36 and 56, the reception pulse is amplified by the amplifiers 38 and 58 and then supplied to the mixers 40, 42, 60 and 62.

  The control circuit 80 controls the switch 76 so that every time a transmission pulse is radiated from the transmission antenna 30, a local pulse to be supplied to the mixers 40, 42, 60, 62 is generated with a predetermined delay time thereafter. . In this case, local pulses are supplied to the mixers 40, 42, 60, 62 after a predetermined delay time from the transmission pulse radiation from the transmission antenna 30.

  The control circuit 80 sets a predetermined delay time from the emission of the transmission pulse from the transmission antenna 30 to the generation of the local pulse corresponding to each range bin in which the detection range is divided into a plurality (for example, 100). It is changed in the order (for example, the order from the range bin whose position is close to the own moving body to the range bin which is far). Specifically, the predetermined delay time is shortened for range bins closer to the self-moving body within the detection range and longer for range bins farther from the self-moving body. Therefore, the local pulses supplied to the mixers 40, 42, 60, and 62 vary in the delay time from the emission of the transmission pulse in accordance with the range bin (position) to be detected at each point in the detection range. It becomes.

  It should be noted that while the transmission pulse is emitted continuously for a predetermined number of times (for example, 10 times), the range bin to be detected is limited to one within the detection range, and the above delay time is set to a constant value during that time. To do. Then, every time the transmission pulse is emitted for a predetermined number of times, the delay time is changed to a value different from the above, and the range bin to be detected is switched to the next range bin.

  The mixers 40, 42, 60, and 62 mix the reception pulses from the reception antennas 36 and 56 and the local pulses from the transmission circuit 22 side, respectively. When there is no target in the range bin to be detected, the mixer output is substantially zero because the received pulse and the local pulse cannot be correlated at that time. On the other hand, when there is a target in the range bin to be detected, the correlation between the received pulse and the local pulse is obtained at that time, so the value is high.

  The mixer outputs are integrated in the integrating circuits 44, 46, 64, and 66 when the same range bin is continuously detected a predetermined number of times. The integrated value is converted into a digital signal by the AD converters 52, 54, 72 and 74 and supplied to the control circuit 80.

  Each time the control circuit 80 generates a local pulse for each range bin within the detection range, whether or not the digital output supplied from the AD converters 52, 54, 72, and 74 reaches a predetermined threshold value. Is determined. As a result, when it is determined that the digital output from the AD converters 52, 54, 72, and 74 does not reach the predetermined threshold value, the correlation between the received pulse and the local pulse cannot be taken, and the delay time of the local pulse is determined. It is determined that no target exists in the corresponding range bin to be detected. On the other hand, when it is determined that the digital output reaches a predetermined threshold value, it is determined that the correlation between the received pulse and the local pulse can be taken, and the delay time of the local pulse that can take the correlation is specified, and detection corresponding to the delay time It is determined that the target exists in the target range bin.

  As described above, in the pulse radar device 20 of the present embodiment, it is possible to determine whether or not a target exists for each range bin in the detection range based on the correlation between the received pulse and the local pulse. The relative distance from the moving body to the target can be detected by specifying the position of the range bin where the target exists based on the time (reflection time) from the transmission of the signal to the reception of the received pulse.

  In the present embodiment, the control circuit 80 uses a pulse pair method for detecting a phase difference between signals (= received pulses) received by reflecting two transmission pulses transmitted with a time interval from the same distance. Then, the relative speed between the moving body and the target existing within the detection range is detected. The relative speed is detected for each range bin in the detection range.

  Specifically, as shown in FIG. 4, when one transmission pulse S is reflected by the target and received by the reception antenna 36 (or 56) as the reception pulse R, the mixers 40, 42 ( Alternatively, the I channel signal I and the Q channel signal Q are output from 60, 62). At this time, if the reception pulse R is a · sin (2πf · t + θ) (where f is the transmission frequency) and the local pulse is sin (2πf · t), the output I of the mixer 40 is a · cos θ, and the mixer 42 Output Q is a · sin θ. The control circuit 80 calculates the phase signal Z (= I + Q) based on the output I of the mixer 40 and the output Q of the mixer 42 (or based on the output I of the mixer 60 and the output Q of the mixer 62).

  Assuming that the target is moving at the relative speed Vr, two transmission pulses S (t11) and S (t21) transmitted at a time Δt are reflected on the target and received as reception pulses R11 and R21, respectively. 36 and 56, the phase signals Z11 and Z21 for the respective receptions are the distances that the target has moved during the time interval Δt during which the two transmission pulses S (t11) and S (t21) are transmitted. It changes by a phase difference Δθ of twice.

  The control circuit 80 detects the phase difference Δθ between the phase signals Z obtained for the transmission of two transmission pulses transmitted at time Δt for each range bin in the detection range. Then, the relative speed Vr of the target is detected according to the relational expression shown in the following (1) based on the detected Δθ for the range bin where the target exists.

Vr = Δθ · λ / (4πΔt) (where λ is the transmission wavelength) (1)
As described above, in the pulse radar device 20 of the present embodiment, with respect to the range bin in which the target in the detection range exists, the received pulse (= phase signal Z from the IQ detector) with respect to the transmission of the two transmission pulses separated by the time Δt. By detecting the phase difference Δθ between them, it is possible to detect the relative velocity Vr of the target with respect to the moving body.

  Further, in this embodiment, the control circuit 80 detects a phase difference between signals (= received pulses) received by two receiving antennas arranged at different positions with respect to one transmitted pulse. Is used to detect the angular position of the target with respect to the moving body. Then, this angular position is detected for each range bin within the detection range.

Specifically, as shown in FIG. 5, when one transmission pulse S is reflected by the target, the reception pulse R _A1 is received by the reception antenna 36, and the reception pulse R _A2 is received by the reception antenna 36, IQ detection is performed. The I channel signal I _A1 and the Q channel signal Q _A1 based on the reception pulse R _A1 are output from the mixers 40 and 42 constituting the detector, and based on the reception pulse R _A2 from the mixers 60 and 62 constituting the IQ detector An I channel signal I _A2 and a Q channel signal Q _A2 are output. The control circuit 80 calculates the phase signal Z _A1 (= I _A1 + Q _A1 ) based on the output I _{A1 of the} mixer 40 and the output Q _{A1 of the} mixer 42, and outputs the output I _{A2 of the} mixer 60 and the output Q of the mixer 42. Based on _A2 , the phase signal Z _A2 (= I _A2 + Q _A2 ) is calculated.

If the target for the moving body is located in a direction shifted by an angle φ with respect to the front direction of the pulse radar device 20 (that is, the direction orthogonal to the straight line connecting the two receiving antennas 36 and 56), The phase signals Z _A1 and Z _A2 based on the reception pulses R _A1 and R _A2 received by the two reception antennas 36 and 56 arranged at a predetermined distance d change by the phase difference Δθ corresponding to the distance d between the antennas. To do.

  The control circuit 80 detects the phase difference Δθ between the phase signals Z based on the reception pulses received by the two reception antennas 36 and 56 for the transmission of one transmission pulse for each range bin within the detection range. Then, for the range bin in which the target exists, the angular position φ of the target is detected according to the relational expression shown in (2) below based on the detected Δθ.

φ = sin ⁻¹ (Δθ · λ / (2πd)) (2)
As described above, in the pulse radar device 20 according to the present embodiment, the two receiving antennas 36 and 56 that are separated by the distance d with respect to the transmission of one transmission pulse are received with respect to the range bin in which the target in the detection range exists. By detecting the phase difference Δθ between the received pulses (= phase signal Z from the IQ detector), it is possible to detect the angular position φ of the target with respect to the own moving body.

  In the pulse radar device 20 of the present embodiment, the control circuit 80 detects the distance to the target, the relative speed Vr of the target, and the angular position φ of the target by the above-described method.

  Specifically, as shown in FIG. 6, it is determined whether or not there is a target in order from a range bin whose position in the detection range is close, and the distance to the target is detected. Further, for each range bin to be detected, the phase difference between the reception pulses of the two reception antennas 36 and 56 is detected to detect the angular position of the target. In this case, for the range bin where the target is present, not only the relative distance of the target but also the relative angular position can be detected.

  When distance detection and angular position detection are performed up to the farthest range bin within the detection range, distance detection and angular position detection are performed again in order from the range bin with the closest position within the detection range. At this time, for each same range bin, the phase difference Δθ between the received pulses with respect to the transmission of the two previous transmission pulses transmitted at a time interval is detected to detect the relative speed of the target. In this case, for the range bin where the target is present, not only the relative distance and relative angular position of the target but also the relative velocity can be detected.

  By the way, in this embodiment, the pulse width W of the transmission pulse that is a transmission radio wave radiated from the transmission circuit 22 corresponds to the minimum distance (distance resolution) A that can be separated as the distance to the target as described above. (W = 2 · A / c is established), it is effective to shorten the pulse width W if the distance resolution A is to be increased (the minimum distance that can be separated is to be shortened). However, if this pulse width W remains constant at a uniform value in the entire detection range, it is possible to improve the target detection accuracy, but an immediate response to medium / long distances due to an increase in processing load. Therefore, it is difficult to perform detection, and it takes a long time to perform target detection within the entire detection range.

  Therefore, the pulse radar device 20 of the present embodiment can change the pulse width W of the transmission pulse from the transmission circuit 22 as appropriate, thereby quickly detecting the medium / long distance and high detection accuracy corresponding to the short distance. To make it compatible. Hereinafter, the characteristic part of the present embodiment will be described with reference to FIGS.

  FIG. 7 shows a flowchart of an example of a control routine executed by the control circuit 80 in the pulse radar device 20 of the present embodiment. 8 and 9 are diagrams for explaining characteristic operations in the pulse radar device 20 of this embodiment. FIG. 8 is a diagram comparing a short range compatible range bin with a medium / long range range bin when viewed from the side of the vehicle, and FIG. The figure showing the length of the range bin for each distance from the vehicle when viewed from above is shown.

  In the pulse radar device 20 according to the present embodiment, the control circuit 80 pulses the transmission pulse so that the transmission pulse is externally radiated from the transmission antenna 30 at the predetermined pulse repetition frequency T while the continuous wave is generated by the continuous wave source 24 as described above. The switch of the forming unit 26 is controlled, and the switch of the pulse forming unit 26 is controlled so that the pulse width W becomes a predetermined value every time one transmission pulse is emitted to the outside.

  Specifically, first of all, within the entire detection range up to the maximum distance Dmax from the moving object to the target to be detected, the transmission pulse is actually emitted from the outside to receive the reflected wave (ie, the target). It is specified whether the position of the detection target is about to be detected (step 100).

  For example, the entire detection range is divided into three detection target positions (for example, a short distance of 10 m from the moving body, a medium distance of 10 m to 50 m, and a long distance of 50 m to 150 m). If it is, it is specified whether the position of the detection target is a short distance, a medium distance, or a long distance. When target detection within the detection range is performed in order from the position close to the moving body to the position farther away with time, the position of the detection target changes in the predetermined order.

  Then, in step 100, when the position of the detection target from which the transmission pulse is actually radiated from now on and the reflected wave is received is specified, the external radiation is now radiated from the present according to the position of the detection target. The pulse width W of the power transmission pulse is varied (step 102). Specifically, when the position of the detection target is close to the own moving body, the pulse width W is relatively short, and when the position of the detection target is far from the own moving body, the pulse width W is relatively long.

  For example, when the position of the detection target is a short distance, the pulse width W of the transmission pulse is set to a relatively short W1, and when the position of the detection target is a medium distance, the pulse width W of the transmission pulse is set to the above-described value. W2 longer than W1 is set, and when the position of the detection target is a long distance, the pulse width W of the transmission pulse is set to W3 longer than W2.

  Note that the control circuit 80 may store the relationship between the position of the detection target and the pulse width W in advance in the memory, and appropriately read and set the pulse width W according to the position of the detection target. When the pulse width W of the transmission pulse is set as described above, the control circuit 80 controls the switches of the pulse forming unit 26 so that the pulse width W is realized.

  According to the processing of the control circuit 80, the pulse width W of the transmission pulse from the transmission circuit 22 is relatively low when the position of the detection target for detecting the target in the entire detection range is a position close to the own moving body. When the position of the detection target for detecting the target in the entire detection range is a position far from the moving body, it can be made relatively long.

  As the pulse width W of the transmission pulse is shorter, the length per one range bin to be detected in the entire detection range is shortened, and the distance resolution for detecting the target is increased. For this reason, according to the configuration of the present embodiment described above, the target is detected with a finer resolution as the position of the detection target for detecting the target in the entire detection range is relatively closer to the moving body. It is possible to improve the detection accuracy of the target existing at that position (see FIGS. 8 and 9).

  On the other hand, as the pulse width W of the transmission pulse is longer, the length per one range bin to be detected in the detection range becomes longer and the number of range bins in the entire detection range becomes smaller. The time required to perform is reduced. Therefore, according to the configuration of the present embodiment, the target can be detected with a wider range bin as the position of the detection target for detecting the target in the entire detection range is relatively far from the moving body. Thus, it is possible to quickly detect the target existing at that position (see FIGS. 8 and 9).

  Therefore, according to the pulse radar device 20 of the present embodiment, in detecting the relative distance, relative speed, and relative angle with the target in the entire detection range, high detection accuracy in the near area and quick detection in the distant area. It is possible to achieve both. In addition, it is possible to realize such coexistence by using a common transmission / reception antenna without separately providing a transmission / reception antenna corresponding to a near field and a transmission / reception antenna corresponding to a remote field.

  In the first embodiment, the transmitting circuit 22 tries to detect the “transmitting means” described in the claims, and the receiving circuits 32 and 34 detect the “receiving means” described in the claims. In the entire detection range up to the maximum distance Dmax to the target to be detected, the position of the detection target from which the transmission pulse is actually radiated to the outside and receiving the reflected wave is now described in the claims. , And the control circuit 80 determines the pulse width W of the transmission pulse to be radiated from the outside to the outside in accordance with the position of the detection target from which the target is to be detected in the entire detection range. By changing the above, the “pulse width varying means” described in the claims is realized.

  By the way, in the first embodiment, the entire detection range of the maximum distance Dmax to the target to be detected is not only divided stepwise into, for example, three detection target positions, but also linearly divided into detection target positions. It is good as well.

  Further, in the first embodiment, the pulse width of the transmission pulse is varied in accordance with the position of the detection target in the process of changing the position of the detection target for target detection within the entire detection range in a predetermined order. However, the timing for changing the pulse width is not limited to this. For example, when the mobile unit travels at a low speed (for example, 10 km / h or less), the mobile unit is close to the surrounding area. Assuming that a state for detecting a target existing in the mobile station is required, that is, assuming that the position of the detection target is relatively close to the own moving body, the pulse width of the transmission pulse is made relatively short, and the self movement When the body travels at a high speed (for example, 40 km / h or more), it is assumed that the mobile body is required to detect a target that is located at a relatively long distance, that is, the position of the detection target As in a position relatively far to the own mobile body, it may be relatively long pulse width of the transmitted pulse.

  It should be noted that such a pulse width may be changed only when target detection is requested by a switch operation or the like by an occupant of a moving body. Also, a target detection request at low speed traveling and a high speed traveling may be performed. The target detection requests may be performed separately and separately.

  In such a modified example, a target existing near the moving body can be detected with fine resolution when traveling at low speed, and the detection accuracy of the target can be improved, and at the same time when traveling at high speed. It is possible to detect a target existing far away from the moving body with a wider range bin, and it is possible to quickly detect the target.

  In addition, when the pulse width is shortened during low-speed traveling as described above, the maximum distance Dmax of the target to be detected is relatively shortened so that the entire detection range is relatively narrow, while the pulse width is increased during high-speed traveling. In this case, the maximum distance Dmax itself may be relatively long so that the entire detection range is relatively wide. Further, the variable of the pulse width according to the traveling speed of the moving body is not limited to the one that corresponds to the low speed traveling and the one that corresponds to the high speed traveling as described above. It is good also as performing linearly according to.

  In the first embodiment described above, the detection to be detected at each time point in the entire detection range regardless of the presence or absence of the target within the entire detection range up to the maximum distance Dmax from the moving object to the target to be detected. The pulse width of the transmission pulse is varied according to the target position.

  On the other hand, in the second embodiment of the present invention, when a target is present in any of the range bins once set in the entire detection range, the pulse width of the transmission pulse for the range bin in which the target is present thereafter. The target detection accuracy is improved by shortening the length per one range bin (distance resolution).

  The pulse radar device 200 of the present embodiment is realized by causing the control circuit 80 to execute the routine shown in FIG. 10 in the configuration of the pulse radar device 20 shown in FIG. Hereinafter, with reference to FIG. 10 and FIG. 11, the characteristic part of a present Example is demonstrated. FIG. 10 shows a flowchart of an example of a control routine executed by the control circuit 80 in the pulse radar device 200 of the present embodiment. FIG. 11 is a diagram for explaining a characteristic operation in the pulse radar device 200 of the present embodiment.

  In the pulse radar apparatus 200 of the present embodiment, the control circuit 80 first starts control from a predetermined number ("1" or more) that defines a total detection range up to the maximum distance Dmax from the mobile body to the target to be detected. 11 is divided into two range bins (hereinafter, this range bin is referred to as the longest range bin). In addition, while performing switch control of the pulse forming unit 26 so that a transmission pulse having a pulse width W1 (= initial value) corresponding to the length of the longest range bin is externally emitted, it corresponds to the position of each longest range bin. By generating a local pulse, it is determined whether or not a target exists based on the digital output from the AD conversion units 52, 54, 72, and 74 for each longest range bin in the entire detection range (target detection; FIG. 11 scan 1). Then, a range bin in which the target exists (hereinafter referred to as a first existing range bin) is detected from the longest range bin obtained by dividing the entire detection range into a predetermined number (step 250).

  When no target exists in any of the longest range bins as a result of the target presence determination for each longest range bin within the entire detection range, and the presence of the first existing range bin is not detected, the control circuit 80 continues to transmit pulses. The pulse width W is maintained at the initial value W1 and the target is detected as described above (step 252). In this case, target detection is continued assuming that the entire detection range is a detection target in the longest range bin.

  On the other hand, when it is detected that the target exists in one of the longest range bins as a result of the target presence determination for each longest range bin within the entire detection range, and the presence of the first existing range bin is detected, The target detection is carried out by setting the pulse width W of the transmission pulse to half of the initial value W1 (= W1 / 2) while only the range of the detected first presence range bin is detected (step 254; Scan 2) in FIG. Specifically, the pulse width W1 / 2 corresponding to the length of the range bin (hereinafter referred to as the second long range bin) obtained by dividing the first existing range bin in half only for the range of the first existing range bin in which the target was present. While performing the switch control of the pulse forming unit 26 so that the transmission pulse it has is radiated to the outside, the local pulse is generated corresponding to the position of each of the second long range bins, thereby the second range bin of the first existence range bin. For each long range bin, it is determined whether a target exists based on the digital output from the AD conversion units 52, 54, 72, 74. Then, the range bin in which the target exists (hereinafter referred to as the second presence range bin) is detected from any second long range bin obtained by dividing the first presence range bin in half. In this case, target detection is continued assuming that the first existence range bin is a detection target in the second long range bin.

  When the second existence range bin in which the target exists is detected as a result of the target existence determination for each second long range bin within the range of the first existence range bin, the control circuit 80 next detects the range of the first existence range bin. The target detection is performed by setting the pulse width W of the transmission pulse to W1 / 4 while setting only the range of the detected second existence range bin as the detection target (step 256; scan 3 in FIG. 11). Then, a range bin in which the target is present (hereinafter referred to as a third existing range bin) is detected from any range bin (hereinafter referred to as a third long range bin) obtained by dividing the second existing range bin in half. In this case, the target detection is continued assuming that the second existence range bin is the detection target in the third long range bin.

  When the third presence range bin is detected, the control circuit 80 similarly shortens the pulse width W of the transmission pulse while reducing the range to be detected among all the detection ranges (that is, the length per one range bin). Target detection is performed until the pulse width W of the transmission pulse reaches a desired length W1 / 2n (n is a natural number equal to or greater than “1”) (that is, the length per one range bin). The target detection is performed until the (n + 1) th range bin in which the target exists is detected from the (n + 1) th range bin of the desired length.

  According to the processing of the control circuit 80, at the beginning of the control, the entire detection range up to the maximum distance Dmax from the moving object to the target to be detected is the detection target, while the pulse width W of the transmission pulse is relatively long. Therefore, the number of range bins to be calculated within the entire detection range can be reduced, and target detection within the entire detection range can be performed quickly in a short time.

  On the other hand, when the first existence range bin in which the target exists is detected from among the longest range bins in which the entire detection range is divided into a plurality, only the range of the first existence range bin is detected among the entire detection ranges. As it becomes a detection target, the pulse width W of the transmission pulse is shortened and halved. Subsequent target detection is performed in the same manner, and the range to be detected of the entire detection range is shortened until the pulse width W of the transmission pulse becomes a desired length.

  When the pulse width W of the transmission pulse is shortened, the distance resolution for detecting the target is increased. For this reason, in the present embodiment, it is possible to improve the detection accuracy of the target in the presence range bin in which the presence of the target is detected. Even if the pulse width W of the transmission pulse is shortened in this way, the range to be detected in the entire detection range is reduced at the same time, so the number of range bins to be calculated in the entire detection range increases. It is possible to prevent the amount of time required for detecting the target from being increased.

  Therefore, according to the pulse radar device 200 of the present embodiment, it is possible to achieve both high detection accuracy and quick detection at a long distance in detecting the relative distance, relative speed, and relative angle with the target within the entire detection range. It is possible. In particular, it is effective for shortening the detection time for detecting the target even when the maximum distance Dmax of the target to be detected is long and the entire detection range is wide or high distance resolution is required.

  In the second embodiment, the control circuit 80 detects the first existence range bin to the nth existence range bin so that the “existence range bin detection means” described in the claims is the k th (k = k =). 1 to n) When the existence range bin is detected, the pulse width W of the transmission pulse for the k-th existence range bin is reduced to half of the previous one (= W1 / 2k). Each “shortening means” is realized.

  By the way, in the second embodiment described above, when it is detected that there is an existing range bin in which the target exists, transmission is then performed while only the range for the detected existing range bin is detected among all the detection ranges. Target detection is performed by setting the pulse width W of the pulse to half that of the previous one, but the pulse width W of the transmission pulse is made different depending on the range bin while all the detection ranges are targeted for detection. For the range bins other than the detected presence range bin, the pulse width W of the transmission pulse is kept the same as before, while the pulse width W of the transmission pulse is halved only for the range of the existence range bin. Thus, target detection may be performed.

  When it is detected that there is an existing range bin in which the target exists, the pulse width W of the transmission pulse is halved (that is, the existing range bin is divided into two). It may be set to / 3 or 1/4 (that is, the existing range bin is divided into three or four).

  Furthermore, in the second embodiment, when it is detected that there is an existing range bin in which the target exists, transmission is performed while only the range for the detected existing range bin is detected among all the detection ranges. Target detection is performed to reduce the pulse width W of the pulse to half of the previous value. When target detection with the desired pulse width W is completed, the target is detected by returning the pulse width W to the initial value W1. May be repeated.

  In the second embodiment described above, in order to achieve both high detection accuracy and detection in a short time, at the beginning of the control, the entire detection range is set as the detection target, and the pulse width W of the transmission pulse is set to a long value in advance. In addition, when it is detected that there is an existing range bin in which the target exists, the target detection is performed by gradually reducing the pulse width W of the transmission pulse to a desired length while narrowing the detection target range. It is said.

  On the other hand, in the third embodiment of the present invention, after setting the pulse width W of the transmission pulse to a desired length from the beginning of the control, the range to be detected is one of all the detection ranges. Limited to the department.

  The pulse radar apparatus 300 of the present embodiment is realized by causing the control circuit 80 to execute the routine shown in FIG. 12 in the configuration of the pulse radar apparatus 20 shown in FIG. Hereinafter, the characteristic part of the present embodiment will be described with reference to FIGS. FIG. 12 shows a flowchart of an example of a control routine executed by the control circuit 80 in the pulse radar device 300 of the present embodiment. FIG. 13 is a diagram for explaining a characteristic operation in the pulse radar apparatus 300 of the present embodiment.

  In the pulse radar apparatus 300 of the present embodiment, the control circuit 80 firstly sets a predetermined number having a desired length over the entire detection range up to the maximum distance Dmax from the moving object to the target to be detected at the beginning of the control. Divide into range bins. In addition, while performing switch control of the pulse forming unit 26 so that a transmission pulse having a pulse width W corresponding to the range bin of the desired length is externally emitted, one front and rear end of each range bin in the entire detection range By generating a local pulse corresponding to only each range bin, it is determined whether or not a target exists for each range bin at the front and rear ends based on the digital output from the AD conversion units 52, 54, 72, and 74. Target detection is performed (step 350; scan 1 in FIG. 13). Then, one range bin at the front end (farthest from the moving body) and one range bin at the rear end (closest from the moving body) are set as the required calculation range bins for target detection, and the required calculation range bins are set. To detect the presence of a target.

  As a result, when it is not detected that the target exists in any of the set required calculation range bins (when a negative determination is made in step 352), the calculation is performed continuously for each of the front and rear range bins. Set the range bin to detect the target.

  On the other hand, when it is detected that a target is present in any of the set required calculation range bins (at the time of an affirmative determination in step 352), one range bin at each of the front and rear ends of each range bin in the entire detection range. , As well as each existing range bin in which the target is detected, and one or a plurality of adjacent range bins adjacent to the front and rear of the existing range bin. Target detection is performed for each range bin (step 354; scan 2 to scan k in FIG. 13). Then, the range bins at the front and rear ends, the existing range bins, and the range bins before and after the existing range bin are set as the required calculation range bins for target detection, and the target calculation target bin is detected from the required calculation range bins. The target detection is continued by appropriately changing the setting of the calculation range bin required according to the detection result.

  According to the processing of the control circuit 80, from the beginning of control, the number of range bins that divide the entire detection range up to the maximum distance Dmax from the moving object to the target to be detected is increased to shorten the length, that is, The pulse width W of the transmission pulse can be set relatively short to obtain a desired distance resolution. For this reason, the distance resolution in detecting the target can be increased, and the detection accuracy of the target can be improved.

  In addition, the calculation range bins that should be detected by the target among all the range bins in the entire detection range are limited to only one range bin at the front and rear ends of the entire detection range at the beginning of the control, and there may be a target. After being detected, the range bin can be limited to one each of the front and rear end range bins, the existing range bin where the target exists, and the range bins before and after the existing range bin. For this reason, the number of range bins subject to calculation within the entire detection range can be reduced compared to a configuration in which all range bins in the entire detection range are all required calculation range bins, and target detection within the entire detection range can be performed. It can be performed quickly in a short time.

  Note that the target does not suddenly appear in the vicinity of the center of the entire detection range, so it can be detected even if the calculation range bins are limited to the front and rear range bins at the beginning of the control as described above. It is reliably prevented that a target that is currently in range is lost during target detection. Even after the presence range bin in which the target is present is detected, the calculation required range bin is limited to the front and rear range bins, the existing range bin, and the range bins around the existing range bin as described above. It is reliably prevented that a target that actually exists or a target that has newly entered the entire detection range is lost during target detection.

  Therefore, according to the pulse radar apparatus 300 of the present embodiment, high detection accuracy and quick detection from near to far are compatible in detecting the relative distance, relative speed, and relative angle with the target in the entire detection range. It is possible to make it. In particular, it is effective for shortening the detection time for detecting the target even when the maximum distance Dmax of the target to be detected is long and the entire detection range is wide or high distance resolution is required.

  In the third embodiment, the control circuit 80 detects the presence range bin in which the target is present among the range bins in the entire detection range, whereby the “existing range bin detection means” described in the claims is provided. After the existence range bin where the target exists is detected, among the all range bins in the entire detection range, the target calculation range bin to be detected is the range bin for each of the front and rear ends of the detection range and the target exists. By limiting to the range bin and the range bins before and after the existing range bin, the “calculation range bin limiting means” described in the claims is realized.

  By the way, in the above third embodiment, at the beginning of the control, among the range bins in the entire detection range, the calculation range bins to be subjected to target detection are limited to only one range bin at the front and rear ends of the entire detection range. However, at the beginning of the control, all the range bins should be detected without limiting the calculation required range bins.

  In the third embodiment, after the existence range bin in which the target is present is detected, the operation required range bin is added to each of the front and rear end range bins of the entire detection range, and the existence range bin and its existence are added. The range bin is limited to one or a plurality of range bins adjacent to the front and back of the range bin, but the position of the range bin to be added as the required calculation range bin is changed according to the relative speed of the target when the existing range bin is detected. It is good to do. For example, when the target approaches the moving body, the number corresponding to the detected existing range bin and the relative speed adjacent to the rear of the existing range bin (the side closer to the moving body) (the higher the relative speed, the more When the target moves away from the moving object, the relative velocity adjacent to the detected existing range bin and the front of the existing range bin (the side far from the moving object) is set. The number of range bins corresponding to the number (the higher the relative speed is, the greater the number) is set as the calculation required range bin. According to such a modified example, it is possible to reliably prevent a target that currently exists within the detection range from being lost during target detection regardless of its relative speed.

  In the first to third embodiments described above, it is assumed that the pulse width of the transmission pulse is variable or the calculation range bins that are required to perform target detection within the entire detection range are limited to a part. In contrast, in the fourth embodiment of the present invention, when it is detected that a target is present in any range bin that divides the entire detection range in order to improve the SN ratio for detecting the target. Then, the number of pulse integrations in the existing range bin is increased.

  The pulse radar device 400 of this embodiment is realized by causing the control circuit 80 to execute the routine shown in FIG. 14 in the configuration of the pulse radar device 20 shown in FIG. Hereinafter, the characteristic part of the present embodiment will be described with reference to FIGS. 14 and 15. FIG. 14 shows a flowchart of an example of a control routine executed by the control circuit 80 in the pulse radar device 400 of the present embodiment. FIG. 15 is a diagram for explaining a characteristic operation in the pulse radar device 400 of this embodiment.

  In the pulse radar device 400 according to the present embodiment, the control circuit 80 divides the entire detection range up to the maximum distance Dmax from the moving object to the target to be detected into a plurality of predetermined range bins, and then determines the length of the range bin. By generating a local pulse corresponding to the position of each range bin while performing switch control of the pulse forming unit 26 so that a transmission pulse having a pulse width W corresponding to the depth is radiated to the outside, Target detection is performed for each range bin (step 450). The target detection in the same range bin is usually the result of integrating the mixer outputs obtained when the transmission pulse is emitted and the reception pulse is received a predetermined number of times c (for example, 10 times) continuously (for example, 10 times). Based on the pulse integration result). Then, an existing range bin in which the target is present is detected from among the range bins within the entire detection range.

  When there is no target in any of the range bins and the presence of the existing range bin is not detected (when a negative determination is made in step 452), the control circuit 80 continues to radiate and receive transmission pulses for each range bin. Is detected based on the integration result of the pulses obtained by integrating the mixer outputs obtained when the signal is continuously received a predetermined number of times c (for example, 10 times).

  On the other hand, when a target exists in any of the range bins and the presence of the existing range bin is detected (when an affirmative determination is made in step 452), the pulse of a pulse required for target detection is subsequently detected for the existing range bin. The number of integrations is increased to a number d (for example, 100 times) greater than the predetermined number of times c (step 454). For the existence range bin, the target detection is continued based on the integration result of the pulses obtained by integrating the mixer outputs obtained when the transmission pulse is radiated and the reception pulse is continuously received d times.

  According to the processing of the control circuit 80, the number of pulse integrations required for target detection is set to the number of times c that allows the target to be detected in advance at the start of control, and then the target is detected. When an existing range bin is detected, only the existing range bin can be increased to a number d that is greater than the number c.

  If the number of pulse integrations increases, the signal-to-noise ratio is improved and the detection sensitivity increases. Therefore, according to the pulse radar device 400 of the present embodiment, it is possible to improve the SN ratio and increase the detection sensitivity in detecting the relative distance, relative speed, and relative angle with the target in the entire detection range. It has become.

  In the configuration of the present embodiment, the number of pulse integrations can be set to a small number in advance before the presence range bin in which the target exists is detected. Compared with the set configuration, target detection within the entire detection range can be quickly performed in a short time.

  In the fourth embodiment, the control circuit 80 detects the presence range bin in which the target is present among the range bins in the entire detection range, whereby the “existing range bin detection means” described in the claims is provided. When the presence range bin in which the target is present is detected, the “integration number increasing means” described in the claims is increased by increasing the number of pulse integration required when performing target detection for the presence range bin. , Each has been realized.

  By the way, in said 4th Example, when the presence range bin in which the target exists is detected among all the detection ranges, the frequency | count of integration of the pulse required when performing target detection about the presence range bin is increased. However, while the number of pulse integrations for the existing range bin is increasing, target detection may not be performed for range bins other than the existing range bins. It is good also as setting to the frequency | count c as usual.

  In the first to fourth embodiments, the relative distance between the moving body and the target is detected by obtaining the correlation between the received pulse and the local pulse. According to such a detection method, it is possible to cope with AD converters 52, 54, 72, and 74 whose calculation speed is relatively low such as a pulse repetition frequency, and it is possible to perform target detection with a simple configuration. Become. However, the method of detecting the relative distance is not limited to this, and the time from the transmission edge of the transmission pulse to the reception edge of the reception pulse is directly measured using an AD converter capable of high-speed calculation. It is good also as realizing by requesting.

  Further, in the first to fourth embodiments, the relative speed between the host vehicle and the target is detected by detecting a signal (= This is performed using a pulse pair method for detecting a phase difference between the received pulses), but may be performed using a method of converting digitized received pulses into frequency components by FFT processing. According to such a configuration, it becomes possible to separately detect the velocity components of a plurality of targets in the same range bin.

  In the first to fourth embodiments described above, detection of the angular position of the target relative to the host vehicle is performed by detecting signals received by two receiving antennas arranged at different positions with respect to one transmission pulse (= reception). The phase comparison monopulse method that detects the phase difference between pulses) is used, but the method may also be performed using a method that compares the received intensities (for example, the sum and difference) of a plurality of receiving antennas. Moreover, it is good also as performing using a phased array and digital beam forming (DBF).

  In the first to fourth embodiments, one transmission antenna 30 and two reception antennas 36 and 56 are provided as shown in FIG. 1, but a plurality of transmission antennas may be provided. . When there are a plurality of receiving antennas, as shown in FIG. 1, the receiving circuit 32 and the receiving circuit 34 may be provided independently corresponding to the receiving antennas 36 and 56, respectively. As described above, one receiving circuit 500 (same configuration as the receiving circuit 32) common to the receiving antennas 36 and 56 and a switch for appropriately switching the receiving antenna connected to each component of the receiving circuit 500 between the receiving antennas 36 and 56. 502 may be provided. According to such a modification, it is possible to share the receiving circuit between the two receiving antennas 36 and 56, thereby simplifying the configuration of the pulse radar device.

  In addition, when a plurality of receiving antennas are provided, as shown in FIG. 16, these receiving antennas may be configured by receiving-only antennas 36 and 56. However, as shown in FIG. It is also possible to provide a switch 602 that switches between the transmitting circuit 22 side and the receiving circuit 500 (similar configuration to the receiving circuit 32) as appropriate, with at least one serving as the transmitting antenna 600. Good. According to such a modification, it is possible to share the transmission antenna and the reception antenna, thereby further simplifying the configuration of the pulse radar device.

  In the modification shown in FIGS. 16 and 17, the switches 502 and 602 are arranged and connected upstream of the amplifier 38, but are arranged and connected downstream of the amplifier 38 in order to improve the SN ratio. It is good as well.

  In the first to fourth embodiments and the modifications shown in FIGS. 16 and 17, the direct conversion method is adopted for the processing of signals to be transmitted and received. However, the down conversion method such as the double conversion method is used. May be any.

  Furthermore, in the first to fourth embodiments described above, in particular in FIGS. 8, 9, 11, 13, and 15 in the embodiment, up to the maximum distance Dmax from the moving body to the target to be detected. However, the present invention is not limited to this, and the detection range is two-dimensional in the front, rear, left, and right, and two-dimensional scanning is performed for target detection. Alternatively, the detection range may be three-dimensional in the front, rear, left, and right directions, and a three-dimensional scan may be performed for target detection. In particular, in the two-dimensional or three-dimensional detection range, the number of range bins is remarkably increased as compared with the one-dimensional detection range. Therefore, the methods of the second embodiment and the third embodiment described above detect the target. It is effective for shortening the time.

20, 200, 300, 400 Pulse radar device 22 Transmitting circuit 30 Transmitting antenna 32, 34 Receiving circuit 36, 56 Receiving antenna 80 Control circuit

Claims (6)

A transmission means for transmitting a pulsed radio wave, and a reception means for receiving a reflected wave of the transmission radio wave by the transmission means, and based on the relationship between the radio wave transmission by the transmission means and the radio wave reception by the reception means A pulse radar device for calculating a relative distance or a relative speed with an object,
An existence range bin detecting means for detecting an existence range bin in which the object is present, out of a range bin in which a detection range in which a relative distance or a relative speed with the object is to be calculated is divided into a predetermined number;
When the presence range bin is detected by the presence range bin detection means, a pulse width shortening means for shortening the pulse width of the radio wave transmitted from the transmission means for the presence range bin, and
A pulse radar device comprising: A transmission means for transmitting a pulsed radio wave, and a reception means for receiving a reflected wave of the transmission radio wave by the transmission means, and based on the relationship between the radio wave transmission by the transmission means and the radio wave reception by the reception means A pulse radar device for calculating a relative distance or a relative speed with an object,
An existence range bin detecting means for detecting an existence range bin in which the object is present among a range bin in which a detection range in which a relative distance or a relative speed with the object is to be calculated is divided into a plurality of ranges;
When the existence range bin is detected by the existence range bin detection means, a calculation range bin that needs to calculate a relative distance or a relative speed with respect to an object among all the range bins in the detection range includes the existence range bin. Calculation range bin limiting means that limits only one or more range bins in the vicinity and one or more range bins present at the end of the detection range;
A pulse radar device comprising:   3. The pulse radar device according to claim 2, wherein the calculation-required range bin is initially only a range bin existing at an end of the detection range. A transmission means for transmitting a pulsed radio wave, and a reception means for receiving a reflected wave of the transmission radio wave by the transmission means, and based on the relationship between the radio wave transmission by the transmission means and the radio wave reception by the reception means A pulse radar device for calculating a relative distance or a relative speed with an object,
An existence range bin detecting means for detecting an existence range bin in which the object is present among a range bin in which a detection range in which a relative distance or a relative speed with the object is to be calculated is divided into a plurality of ranges;
When the presence range bin is detected by the presence range bin detection means, the number of integrations is increased to increase the number of times of integration processing of the received radio wave necessary for calculating the relative distance or relative speed of the presence range bin with the object. Means,
A pulse radar device comprising:   The pulse width varying means for varying the pulse width of the radio wave transmitted by the transmitting means according to the position of the required detection range where the calculation of the relative distance or relative speed with the object is required. The pulse radar device according to any one of 1 to 4.   The pulse width varying means shortens the pulse width as the position of the required detection range is closer, while increasing the pulse width as the position of the required detection range is farther. The pulse radar device according to claim 5.