JP2007286033A - Radio detector and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce incorrect detection of objects to be detected in front. <P>SOLUTION: When reception signals to transmission signals from a wide-angle transmitting antenna are received (S1 to S3 YES), for example, a monopulse radar first computes angles on the basis of the reception signals and determines whether the presence of targets in front is possible or not on the basis of the angles (S4, S5). When it is determined that their presence is possible, the monopulse radar changes over to a narrow-angle transmitting antenna having a narrower half-value angle of directivity than that of the wide-angle transmitting antenna (S6), computes angles on the basis of reception signals to transmission signals from the narrow-angle transmitting antenna, and determines whether targets in front are detected or not on the basis of the angles (S7 to S10). When it is determined that the targets in front are detected, the monopulse radar outputs target detection signals (S11). The present invention can be applied to monopulse radars. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio wave detection apparatus and method, and in particular, when detecting an object, whether the detection is a correct detection for the actual existence of the object or a plurality of objects. The present invention relates to a radio wave detection apparatus and method for confirming whether a detection error has occurred.

  Conventionally, in order to avoid a collision between the own vehicle and another vehicle, a monopal radar is sometimes mounted on the own vehicle as a radio wave detection device (radar) for detecting another vehicle with a possibility of collision (for example, a patent) Reference 1).

  The monopulse method is a method for performing angle detection. That is, the monopulse radar detects the angle of the detection target object with respect to the front center direction of itself. In other words, when a monopulse radar is mounted in the front part of the own vehicle, the other vehicle in front of the own vehicle becomes a detection target, and the angle of the other vehicle in front of the own vehicle is detected by the monopulse radar. On the other hand, when a monopulse radar is mounted in the rear part of the own vehicle, the other vehicle behind the own vehicle becomes a detection target, and the angle of the other vehicle behind the own vehicle is detected by the monopulse radar.

  Hereinafter, the monopal type will be further described with reference to FIGS.

  As shown in FIG. 1, in the conventional monopulse radar 1, a transmission antenna 11 is provided, and reception antennas 12 -L and 12 -R are provided on the left and right sides of the transmission antenna 11, respectively.

  A transmission signal Ss is transmitted from the transmission antenna 11.

  The transmission signal Ss is reflected by the detection object 2, and the reflected signal is received as the reception signal Srl by the left reception antenna 12-L and is received as the reception signal Srr by the right reception antenna 12-R. .

  Therefore, the monopulse radar 1 calculates the angle θ of the detection object 2 by the monopulse method using the reception signal Srl and the reception signal Srr.

  In this case, the monopulse type can be broadly divided into a phase monopulse type and an amplitude monopulse type.

  The phase monopulse type refers to the following type.

  That is, as shown in FIG. 1, the distance between the detection object 2 and the left reception antenna 12-L is different from the distance between the detection object 2 and the right reception antenna 12-R. A phase difference Δφ is generated between the signal Srl and the received signal Srr. In this case, when the distance between the two receiving antennas 12-L and 12-R is described as d, the angle θ of the detection target object 2 is represented by the following equation (1).

Δφ = (2πd / λ) sin θ (1)
In equation (1), λ represents the wavelength of the received signals Srl and Srr.

  Accordingly, the monopulse radar 1 detects the phase difference Δφ between the reception signal Srl and the reception signal Srr, and calculates the angle θ of the detection target object 2 based on the phase difference Δφ and the equation (1). To do.

  Such a system is a phase monopulse type.

  On the other hand, the amplitude monopulse method refers to the following method.

  That is, the directivity Dr of the left receiving antenna 12-L and the directivity Dr of the right receiving antenna 12-R are distributed as in the gain characteristic of FIG. In this case, the signal strength due to the sum signal of the reception signal Srr from the left reception antenna 12-L and the reception signal Srr from the right reception antenna 12-R, and the signal strength due to the difference signal between the reception signal Srl and the reception signal Srr. Are respectively a curve Sadd and a curve Sdif shown by the gain characteristics in FIG. Further, the ratio of the signal strengths of the sum signal and the difference signal is represented by a curve R1 shown by the gain characteristic in FIG.

  Therefore, the monopulse radar 1 uses the reception signal Srl of the left reception antenna 12-L and the reception signal Srr of the right reception antenna 12-R to generate each of the sum signal and the difference signal. Then, the ratio of the signal intensity of the sum signal and the difference signal is calculated, and the calculation result is compared with the gain characteristic data of FIG. θ is calculated.

Such a method is an amplitude monopulse type.
JP 2002-267750 A

  However, in the conventional monopal radar 1, as shown in FIG. 5, in addition to the case where the detection target 2 exists in the front left and the detection target 3 exists in the front right, the angle θ is An angle close to 0 degrees is detected. As a result, even though there is actually nothing in the vicinity of the front center direction, the conventional monopulse radar 1 detects as if the detection object 4 is present in the vicinity of the front center direction. There is a problem that the detection object 4 that is only a phantom is detected.

  The cause of this problem is as follows. That is, as shown in FIG. 5, at the left receiving antenna 12-L, the reflected signal of the transmission signal Ss2 on the detection target 2 is received as the reception signal Sr2l, and the transmission signal Ss3 is reflected on the detection target 3 The signal is received as the reception signal Sr3l. Similarly, at the right receiving antenna 12-R, the reflection signal of the transmission signal Ss2 on the detection target 2 is received as the reception signal Sr2r, and the reflection signal of the transmission signal Ss3 on the detection target 3 is received as the reception signal Sr3r. Will be. Therefore, for the conventional monopulse radar 1, the mixed signal of the received signal Sr2l and the received signal Sr3l is used as the received signal of the left receiving antenna 12-L, and the mixed signal of the received signal Sr2r and the received signal Sr3r is used as the right signal. The angle is detected using the received signals of the receiving antenna 12-R. As a result, the above-described problem occurs.

  In this case, when the relative speed v1 of the detection target 2 and the relative speed v2 of the detection target 3 with respect to the monopulse radar 1 are different, the frequencies of the reception signal Sr2l and the reception signal Sr3l are different due to the Doppler effect. Further, the frequencies of the reception signal Sr2r and the reception signal Sr3r are different from each other. Therefore, if it is a monopulse radar that can detect the frequency (hereinafter referred to as the Doppler frequency), phase, etc. of the Doppler signal, for example, if it is a monopulse radar that employs the two-frequency CW method (see Patent Document 1), Since the received signal Sr2l can be distinguished from the received signal Sr3l, and the received signal Sr2r can be distinguished from the received signal Sr3r, the above-described problem can be solved.

  However, when the relative speed v1 of the detection target 2 and the relative speed v2 of the detection target 3 are the same, no Doppler frequency is generated. That is, the frequency of the reception signal Sr2l and the reception signal Sr3l is the same, and the frequency of the reception signal Sr2r and the reception signal Sr3r is the same. Therefore, even in a monopulse radar adopting the two-frequency CW method, it is impossible to distinguish between the reception signal Sr2l and the reception signal Sr3l, and it is impossible to distinguish between the reception signal Sr2r and the reception signal Sr3r. As a result, the above-mentioned problem still occurs.

  To summarize the above, in the conventional monopulse radar, when a detection object in the vicinity of the front center direction is detected, is the detection actually correct because there is a detection object in front? This results in the problem that it is impossible to accurately specify whether the detection object is a detection error because there is one detection object in front of the left and right.

  The present invention has been made in view of such a situation.When an object is detected in a predetermined range in front, is the detection actually correct because an object in front is present? Or it confirms more certainly whether it is a false detection.

  A radio wave detection device according to an aspect of the present invention is a radio wave detection device that uses a plurality of antennas and detects an object existing ahead based on reception signals received by two or more of these antennas, When the received signals received by the two or more antennas are used to specify the position of the object, and the position specified by the position specifying means is within a predetermined range, And an object detection means for confirming the existence.

  As a result, when a detection object in front is detected, that is, when it is determined that there is a possibility that the detection object exists, is the detection actually correct detection for the presence of the front object? Alternatively, it is possible to accurately identify whether the detection is an error due to the existence of one object at each of the left and right fronts.

  The plurality of antennas are constituted by antennas mounted on, for example, a monopulse radar.

  Each of the position specifying means and the object detection means is configured to include a circuit that performs signal processing, a computer that executes signal processing as software, and the like. It is described as including other components, for example, an antenna for receiving a signal to be processed, or a camera or a sensor that outputs a signal to be processed. Because it can.

  When the position specified by the position specifying means is within the predetermined range, the object detecting means has directivity with respect to the first transmission signal corresponding to the reception signal used by the position specifying means. Narrow-angle transmission means for transmitting a second transmission signal having a narrow angle, and the presence of the object is confirmed based on a signal obtained by reflecting the second transmission signal from the narrow-angle transmission means by the object. Confirming means.

  The plurality of antennas include a first antenna that transmits the first transmission signal and a second antenna as the narrow-angle transmission unit that transmits the second transmission signal. Can do.

  The position specifying means calculates an angle by a monopulse method, specifies the position of the object based on the angle, and the confirmation means determines that a signal obtained by reflecting the second transmission signal by the object is An angle can be calculated by a predetermined method using each received signal when received by each of two or more antennas, and the presence of the object can be confirmed based on the calculation result.

  Thereby, a part of the conventional monopulse radar can be used, and a radio wave detection device can be easily realized.

  When the position specified by the position specifying means is within a predetermined range, the transmitting antenna is switched to the second transmitting antenna, and after the confirmation of the presence of the object by the checking means is completed, Switching means for switching the antenna to the first transmission antenna can be further provided.

  Thereby, when the position of the object is specified by the position specifying means, the first transmission antenna is reliably used, and when the object is confirmed by the confirmation means, the second transmission antenna is surely used.

  The switching means is composed of a 1-input 2-output switch circuit, for example.

  Speed distance calculation means for calculating at least one of a relative speed and a distance to the detection target object using at least a part of the reception signals received by the two or more reception antennas is further provided. The position specifying means further uses at least a part of the calculation result of the speed distance calculation means to specify the position of the object, and the confirmation means includes the calculation result of the speed distance calculation means. The presence of the object can be confirmed by further using at least a part of.

  Thereby, since the determination material which can be used for specifying the position of the object by the specifying means and checking the object by the checking means increases, the detection of the object can be realized more accurately.

  When the position specified by the position specifying means is within a predetermined range, the target detecting means confirms the presence of the target using a technique different from the technique applied to the position specifying means. can do.

  The object detection means in this case is configured using, for example, any one or a plurality of ultrasonic sensors, laser radars, image sensors using cameras, and the like.

  As a result, the object is recognized by the two methods, so that a more accurate detection of the object can be realized.

  A radio wave detection method according to an aspect of the present invention is a radio wave detection device detection method that uses a plurality of antennas and detects an object existing ahead based on reception signals received by two or more of these antennas. Then, using each received signal received by the two or more antennas, the position of the object is specified, and when the specified position is within a predetermined range, the step of confirming the presence of the object is performed. Including.

  As a result, when a detection object in front is detected, that is, when it is determined that there is a possibility that the detection object exists, is the detection actually correct detection for the presence of the front object? Alternatively, it is possible to accurately identify whether the detection is an error due to the existence of one object at each of the left and right fronts.

  As described above, according to the present invention, a front object can be detected. In particular, erroneous detection at that time can be reduced. Specifically, when an object is detected within a predetermined range in front, it can be confirmed more reliably whether the detection is a correct detection for the presence of the object in front or a false detection. .

  First, with reference to FIGS. 6 and 7, one of the techniques to which the present invention is applied (hereinafter simply referred to as the technique of the present invention) will be described. Other methods to which the present invention is applied will be described later.

  The method of the present invention described here is based on the premise that the detection object near the front center direction is detected by the monopulse method. Such detection is executed by the monopulse radar 51 shown in FIGS.

  Here, the front refers to the front for the monopulse radar 51, that is, the upward direction in the drawings in FIGS. However, if attention is paid to the own vehicle on which the monopulse radar 51 is mounted, as described above in [Background Art], depending on where the monopulse radar 51 is mounted, the front here may be the front for the own vehicle. It will be behind.

  The monopulse radar 51 includes, in addition to the conventional antenna, that is, in addition to the two reception antennas 62-L and 62-R and the transmission antenna 61-W (FIG. 6), further from the transmission antenna 61-W. Has a transmitting antenna 61-N (FIG. 7) having a narrow half-value angle of directivity. That is, the monopulse radar 51 includes a transmission antenna 61-W having a directivity half-value angle of θw and a transmission antenna 61-N having a directivity half-value angle of θn (θn <θw). The transmission antennas 61-W and 61-N can be switched freely.

  Hereinafter, the transmission antenna 61-W is referred to as a wide-angle transmission antenna 61-W, and the transmission antenna 61-N is referred to as a narrow-angle transmission antenna 61-N.

  First, as shown in FIG. 6, the monopulse radar 51 uses a wide-angle transmitting antenna 61-W to detect a detection object in the vicinity of the front center direction (hereinafter referred to as a wide-angle detection). More precisely, since the actual detection is performed using the narrow-angle transmission antenna 61-N as described later, in the wide-angle detection, it is determined whether or not there is a detection object near the front center direction. become.

  For example, in the wide-angle detection of the present embodiment, the reception signals are received by the reception antennas 62-L and 62-R, and the monopulse detection angle with respect to the reception signals is equal to or less than a threshold value (for example, an angle smaller than θn in FIG. 7). In such a case, it is determined that there is a possibility that a detection object near the front center direction exists. On the other hand, in other cases, that is, when the reception signal is not received by the reception antennas 62-L and 62-R, or when the reception signal is received, the monopulse detection angle with respect to the reception signal has a threshold value. If it exceeds, it is determined that there is no possibility of the detection object near the front center direction.

  However, the wide-angle detection method is not particularly limited to the method of the present embodiment, and any method may be used as long as it uses a monopulse method. For example, when the monopulse radar 51 can measure not only the angle of the detection target object but also its relative speed and distance, for example, when it is configured as shown in FIG. It is also possible to adopt a method of determining whether or not there is a detection object near the front center direction in consideration of the above.

  When such a wide-angle detection detects the presence of a detection object in the vicinity of the front center direction, the monopulse radar 51 further uses a narrow-angle transmission antenna 61-N as shown in FIG. Then, a detection object in the vicinity of the front center direction is detected (hereinafter referred to as narrow angle detection).

  In the narrow-angle detection according to the present embodiment, the same technique as that of the above-described wide-angle detection according to the present embodiment is applied. That is, in the narrow-angle detection of the present embodiment, the reception signals are received by the reception antennas 62-L and 62-R, and the monopulse detection angle with respect to the reception signal is a threshold (for example, the threshold of the wide-angle detection in this embodiment). Or less), it is determined that a detection object near the front center direction has been detected. On the other hand, in other cases, that is, when the reception signal is not received by the reception antennas 62-L and 62-R, or when the reception signal is received, the monopulse detection angle with respect to the reception signal has a threshold value. If it exceeds, it is determined that the detection object near the front center direction is not detected.

  However, the narrow-angle detection method is not particularly limited to the method of the present embodiment, and any method may be used as long as it uses a monopulse method. For example, since the wide-angle detection itself has been completed, it is also possible to employ a method in which the presence / absence of detection of a detection object in the vicinity of the front center direction is determined simply by the presence / absence of a received signal. Further, for example, when the monopulse radar 51 can measure not only the angle of the detection target object but also the relative speed and distance thereof, for example, when configured as shown in FIG. It is also possible to adopt a method of determining the presence / absence of detection of a detection object near the front center direction in consideration of the distance.

  In the present embodiment, the threshold used for wide-angle detection and the threshold used for narrow-angle detection are the same angle. However, it is also possible to adopt different angles for both thresholds.

  In this way, when the monopulse radar 51 detects a detection object in the vicinity of the front center direction by wide-angle detection, the monopulse radar 51 performs further narrow-angle detection without making the detection a final detection result. Only when a detection object in the vicinity is detected, the detection is adopted as a final detection result. This makes it possible to obtain a more accurate final detection result.

  In other words, conventionally, only the wide-angle detection here is performed, and the detection result is directly adopted as the final detection result. However, as described above, such a wide-angle detection result is actually a correct detection result for the presence of a front detection object, or because there is one detection object at each of the left and right fronts. It was difficult to identify whether it was a false detection result. In particular, when the relative speeds of the detection objects existing one by one in the front left and right are the same, the identification is very difficult.

  On the other hand, the monopulse radar 51 uses the detection result of the narrow-angle detection, so that the wide-angle detection result is the correct detection result due to the presence of the detection object in front, or Therefore, it is possible to accurately specify whether the detection result is due to the presence of detection objects one by one in the front left and right.

  Specifically, for example, as shown in FIG. 6, the wide-angle transmission antenna 61 -W is used when the detection target object 2 exists in the front left and the detection target 3 exists in the front right. When the wide-angle detection is performed, an angle close to 0 degrees is detected as described above with reference to FIG. As a result, although there is actually nothing in the vicinity of the front center direction, it is detected as if the detection target object 4 exists. That is, the detection object 4 that is only a phantom is detected.

  Therefore, in such a case, as shown in FIG. 7, the monopulse radar 51 further performs narrow-angle detection using the narrow-angle transmission antenna 61-N. At this time, regardless of the relative speed v1 of the detection object 2 and the relative speed v2 of the detection object 3, that is, even when the relative speed v1 and the relative speed v2 are the same, the narrow-angle transmission antenna 61- Since the transmission signal from N does not reach the detection object 2 and the detection object 3, the reception signals are not received by the reception antennas 62-L and 62-R. As a result, the monopulse radar 51 is independent of the relative speed v1 of the detection target 2 and the relative speed v2 of the detection target 3, that is, even when the relative speed v1 and the relative speed v2 are the same. It is possible to determine that there is no detection target in the vicinity of the front center direction, that is, it is possible to determine that the detection target 4 detected by the wide-angle detection is only a phantom.

  On the other hand, as shown in FIGS. 14 and 15 to be described later, when an actual detection target object (detection target object 5 in the examples of FIGS. 14 and 15) exists in the vicinity of the front center direction, A transmission signal from the wide-angle transmission antenna 61-W and a transmission signal from the narrow-angle transmission antenna 61-N reach the detection target. As a result, the actual object to be detected is detected by both wide-angle detection and narrow-angle detection.

  The method of performing the wide angle detection and the narrow angle detection described above is one of the methods of the present invention.

  A functional block diagram showing functions of the monopulse radar 51 to which the method of the present invention is applied is shown in FIG.

  The monopulse radar 51 in the example of FIG. 8 includes the above-described antennas, that is, the wide-angle transmission antenna 61-W, the narrow-angle transmission antenna 61-N, the reception antenna 62-L, and the reception antenna 62-R. Yes. Further, in the monopulse radar 51, a transmission signal generator 63 to a front target detector 68 are provided.

  The transmission signal generation unit 63 generates a transmission signal and provides it to the switching unit 64.

  The form of the transmission signal generated by the transmission signal generation unit 63 is not particularly limited as long as it can be transmitted from the wide-angle transmission antenna 61-W and the narrow-angle transmission antenna 61-N. A specific example of the transmission signal will be described later with reference to FIG.

  Based on the control of the switching control unit 67, which will be described later, the switching unit 64 sets the output destination of the transmission signal from the transmission signal generation unit 63 among the wide-angle transmission antenna 61-W side and the narrow-angle transmission antenna 61-N side. Switch to one of these sides.

  That is, when the output destination of the switching unit 64 is switched to the wide-angle transmission antenna 61-W side, the transmission signal from the transmission signal generation unit 63 is output from the wide-angle transmission antenna 61-W, using FIG. The wide-angle detection described above is performed.

  On the other hand, when the output destination of the switching unit 64 is switched to the narrow-angle transmission antenna 61-N side, the transmission signal from the transmission signal generation unit 63 is output from the narrow-angle transmission antenna 61-N, and FIG. The above-described narrow angle detection is performed.

  When a detection target exists, the transmission signal from the wide-angle transmission antenna 61-W or the narrow-angle transmission antenna 61-N is reflected by the detection target, and the reflected signal is received as a reception signal. , 62-R.

  When the monopulse radar 51 adopts the phase monopulse type, the reception signal extraction unit 65-L extracts the reception signal received by the reception antenna 62-L as shown by the solid line in FIG. In response to this, it is appropriately converted into another form that can be used by the angle calculation unit 66 to be described later, and provided to the angle calculation unit 66 as an output signal. Further, the reception signal extraction unit 65-R extracts the reception signal received by the reception antenna 62-R, and further appropriately converts it into another form that can be used by the angle calculation unit 66 described later, if necessary. Then, it is provided as an output signal to the angle calculator 66.

  On the other hand, when the monopulse radar 51 adopts the amplitude monopulse type, the reception signal extraction unit 65-L receives the reception signal received by the reception antenna 62-L as indicated by a solid line and a dotted line in the figure. A sum signal with the received signal received by the receiving antenna 62-R is extracted, and further converted into a form that can be used by an angle calculating unit 66, which will be described later, as necessary. 66. The reception signal extraction unit 65-R extracts a difference signal between the reception signal received by the reception antenna 62-L and the reception signal received by the reception antenna 62-R, and will be described later if necessary. The angle calculation unit 66 appropriately converts it into a form that can be used and provides it to the angle calculation unit 66 as an output signal.

  The angle calculation unit 66 calculates the angle according to the phase monopulse type or the amplitude monopulse type using the output signals of the reception signal extraction units 65-R and 65-L. The calculation result of the angle calculation unit 66 is notified to the front target detection unit 68.

  The switching control unit 67 performs control to switch the output destination of the switching unit 64 in accordance with a switching command from the forward target detection unit 68 described later.

  The forward target detection unit 68 performs the above-described wide-angle detection or narrow-angle detection based on the angle notified from the angle calculation unit 66. When it is determined that the detection target near the front center direction is detected in the narrow-angle detection after the wide-angle detection, the front target detection unit 68 outputs a signal indicating the detection to the outside. The front target detection unit 68 issues a switching command to the switching control unit 67 when switching from wide-angle detection to narrow-angle detection or when switching from narrow-angle detection to wide-angle detection. Hereinafter, a signal output from the forward target detection unit 68 is referred to as a target detection signal. In addition, along with this designation, a detection target near the front center direction is also referred to as a front target.

  Note that the switching control unit 67 and the forward target detection unit 68 can be omitted. That is, the monopulse radar 51 can only perform angle detection. In this case, however, the functions of the switching control unit 67 and the forward target detection unit 68 need to be delegated to an external signal processing device (not shown).

  A processing example of the monopulse radar 51 having the functional configuration of FIG. 8 is shown in the flowchart of FIG.

  In step S <b> 1 of FIG. 9, the switching unit 64 switches the output destination to the wide-angle transmission antenna 61 -W side based on the control of the switching control unit 67.

  In step S <b> 2, the wide-angle transmission antenna 61 -W transmits the transmission signal provided from the transmission signal generation unit 63 via the switching unit 64.

  In step S3, the angle calculation unit 66 determines whether or not a reception signal has been received.

  While the output signals of the reception signal extraction units 65-L and 65-R have not been provided, it is determined in step S3 that the reception signal has not been received, and the process returns to step S1. The process is repeated. In this case, since the output destination of the switching unit 64 has already been switched to the wide-angle transmission antenna 61-W side, the process proceeds to step S2 without substantially executing the process of step S1.

  Thereafter, when one or more detection objects such as other vehicles have entered the range of ± θw in FIG. 6, the transmission signals transmitted in the process of step S2 are reflected by the one or more detection objects, respectively. Each reflected signal is received by the receiving antennas 62-L and 62-R. Then, as described above, the output signals of the reception signal extraction units 65 -L and 65 -R are provided to the angle calculation unit 66. Therefore, in step S4, the angle calculation unit 66 calculates the angle according to the phase monopulse type or the amplitude monopulse type using the output signals of the reception signal extraction units 65-L and 65-R, and the calculation result is used as the front target. The detection unit 68 is notified.

  In step S <b> 5, the forward target detection unit 68 determines whether or not there is a forward target based on the angle notified from the angle calculation unit 66. As described above, in the present embodiment, the forward target detection unit 68 determines whether or not the angle notified from the angle calculation unit 66 is a threshold value (for example, an angle smaller than θn in FIG. 7) or less. It is determined whether there is a possibility that a forward target exists.

  If it is determined in step S5 that there is no possibility of the presence of the front target, that is, if the angle exceeds the threshold in the present embodiment, the process returns to step S1, and the subsequent processes are repeated. In this case, since the output destination of the switching unit 64 has already been switched to the wide-angle transmission antenna 61-W side, the process proceeds to step S2 without substantially executing the process of step S1.

  On the other hand, when it is determined in step S5 that there is a possibility of the presence of the front target, that is, in this embodiment, when the angle is equal to or smaller than the threshold value, the front target detection unit 68 issues a switching command to the switching control unit 67. And the process proceeds to step S6.

  In step S6, the switching unit 64 switches the output destination to the narrow-angle transmission antenna 61-N side based on the control of the switching control unit 67 that has received the switching command.

  In step S <b> 7, the narrow-angle transmission antenna 61 -N transmits the transmission signal provided from the transmission signal generation unit 63 via the switching unit 64.

  In step S8, the angle calculation unit 66 determines whether or not a reception signal has been received.

  Specifically, for example, although an arrow or the like is not illustrated in FIG. 8, it is assumed that the angle calculation unit 66 can acquire the transmission timing of the transmission signal in step S <b> 7 from the transmission signal generation unit 63. In this case, when the output signals of the reception signal extraction units 65-L and 65-R are not provided even after a predetermined time has elapsed from the transmission timing, the angle calculation unit 66 determines in step S8 that the reception signal is It is determined that it has not been received. Then, the determination result is notified to the front target detection unit 68, and upon receiving the notification, a switching command is issued from the front target detection unit 68 to the switching control unit 67, and the process returns to step S1. In step S1, the output destination of the switching unit 64 is switched to the wide-angle transmission antenna 61-W side, and the processes in and after step S2 are executed.

  On the other hand, when the output signals of the reception signal extraction units 65-L and 65-R are provided before a predetermined time has elapsed from the transmission timing of the transmission signal, the angle calculation unit 66 In step S8, it is determined that the received signal has been received. In step S9, the angle calculation unit 66 calculates the angle according to the phase monopulse type or the amplitude monopulse type using the output signals of the reception signal extraction units 65-L and 65-R, and outputs the calculation result to the front target. The detection unit 68 is notified.

  In step S <b> 10, the front target detection unit 68 determines whether or not a front target has been detected based on the angle notified from the angle calculation unit 66. As described above, in the present embodiment, the forward target detector 68 determines whether or not a forward target has been detected based on whether or not the angle notified from the angle calculator 66 is equal to or less than a threshold value. .

  Note that, as described above, the threshold value used in the process of step S10 is the same angle as the threshold value used in the process of step S5 in the present embodiment, but different angles may be employed. it can.

  When it is determined in step S10 that the front target has not been detected, that is, in the present embodiment, when the angle exceeds the threshold value, a switching command is issued from the front target detection unit 68 to the switching control unit 67. The process is returned to step S1. In step S1, the output destination of the switching unit 64 is switched to the wide-angle transmission antenna 61-W side, and the processes in and after step S2 are executed.

  On the other hand, when it is determined in step S10 that the front target has been detected, that is, in the present embodiment, if the angle is equal to or smaller than the threshold value, the front target detector 68 outputs a target detection signal in step S11. .

  In step S12, the front target detection unit 68 determines whether or not an instruction to end the process is given.

  In step S12, when it is determined that the end of the process is instructed, the process of the monopulse radar 51 is ended.

  On the other hand, if it is determined in step S12 that the process has not been instructed yet, the front target detection unit 68 issues a switching command to the switching control unit 67, and the process returns to step S1. . In step S1, the output destination of the switching unit 64 is switched to the wide-angle transmission antenna 61-W side, and the processes in and after step S2 are executed.

  As described above, the monopulse radar 51 to which the present invention is applied does not immediately output the target detection signal when detecting the front target in the wide-angle detection, and the detection only indicates the possibility of existence. Narrow-angle detection is further performed. The monopulse radar 51 outputs a target detection signal only when the front target is detected even in the narrow-angle detection.

  That is, the monopulse radar 51 performs narrow-angle detection, so that the wide-angle detection performed before that is actually the correct detection for the presence of the front target, or is separated one by one on the left and right fronts. It is determined whether it was a false detection due to the existence of the target. The monopulse radar 51 outputs a target detection signal only when it is determined that the detection is correct.

  As a result, a signal processing unit (not shown) that performs processing for avoiding a collision between the host vehicle and another vehicle using the target detection signal can accurately execute the processing. That is, it is possible to significantly reduce collision detection errors and the like.

  By the way, the above-described series of processes (or a part of the processes), for example, the process according to the flowchart of FIG. 9 described above can be executed by hardware or can be executed by software.

  When the series of processes (or a part of the processes) is executed by hardware, the monopulse radar 51 can be configured as shown in FIG. 10, for example. That is, FIG. 10 shows a hardware configuration example of a monopulse radar 51 that employs an amplitude monopulse system.

  In the example of FIG. 10, the transmission signal generation unit 63 is configured to include a two-frequency CW oscillation unit 71, a modulation unit 72, and an amplification unit 73.

  The two-frequency CW oscillating unit 71 oscillates a signal (hereinafter referred to as a two-frequency CW) obtained as a result of switching, for example, a CW (Continuous Wave) having a frequency f1 and a CW having a frequency f2 in a time division manner as a carrier wave. 72.

  The modulation unit 72 performs AM (Amplitude Modulation) modulation on the two-frequency CW, for example, and provides a signal obtained as a result to the amplification unit 73. Note that AM is merely an example, and the modulation method by the modulation unit 72 may be arbitrary.

  The amplifying unit 73 appropriately performs various processing such as amplification processing on the two-frequency CW modulated by the modulating unit 72, and provides a signal obtained as a result to the switching unit 64 as an output signal. The output signal of the amplifying unit 73 is provided to the wide-angle transmitting antenna 61-W or the narrow-angle transmitting antenna 61-N via the switching unit 64, and is output as a transmission signal in the form of radio waves.

  The transmission signal is reflected by the detection object, and the reflected signal is received as a reception signal by each of the reception antennas 62-L and 62-R and provided to both of the reception signal extraction units 65-L and 65-R. .

  The received signal extraction unit 65-L includes a sum signal generation unit 81-L, an amplification unit 82-L, a mixing unit 83-L, an LPF unit 84-L, an A / D conversion unit 85-L, and an FFT unit 86-. L is included.

  The sum signal generation unit 81-L generates a sum signal of the reception signal received by the reception antenna 62-L and the reception signal received by the reception antenna 62-R, and provides it to the amplification unit 82-L.

  The amplifying unit 82-L appropriately performs various processing such as amplification processing on the sum signal from the sum signal generating unit 81-L, and provides the resulting signal to the mixing unit 83-L as an output signal.

  The mixing unit 83-L mixes the output signal of the amplification unit 82-L and the transmission signal from the transmission signal generation unit 63, and provides the resulting signal to the LPF unit 84-L as an output signal. The LPF unit 84-L performs an LPF (Low Pass Filter) process on the output signal of the mixing unit 83-L, and provides the resulting signal to the A / D conversion unit 85-L as an output signal. The A / D conversion unit 85-L performs A / D conversion (Analog to Digital) processing on the output signal of the LPF unit 84-L, and uses the resulting digital signal as an output signal to the FFT unit 86-L. provide.

  The FFT unit 86-L performs an FFT (Fast Fourier Transform) analysis process on the output signal of the A / D conversion unit 85-L, that is, the digital sum signal, and the FFT analysis result of the sum signal is converted into an angle calculation unit. 66 and a relative speed / distance calculation unit 69.

  In contrast to the reception signal extraction unit 65-L having such a configuration, the reception signal extraction unit 65-R is configured as follows. That is, the received signal extraction unit 65-R includes a difference signal generation unit 81-R, an amplification unit 82-R, a mixing unit 83-R, an LPF unit 84-R, an A / D conversion unit 85-R, and an FFT unit 86. -R is included.

  The difference signal generation unit 81-R generates a difference signal between the reception signal received by the reception antenna 62-L and the reception signal received by the reception antenna 62-R, and provides the difference signal to the amplification unit 82-R.

  The amplification unit 82-R, the mixing unit 83-R, the LPF unit 84-R, the A / D conversion unit 85-R, and the FFT unit 86-R are respectively the amplification unit 82-L and the mixing unit 83-L. The LPF unit 84-L, the A / D conversion unit 85-L, and the FFT unit 86-L have basically the same configurations and functions. Therefore, the individual description of each part is omitted.

  The reception signal extraction unit 65 -R having such a configuration eventually outputs the FFT analysis result of the difference signal and provides it to the angle calculation unit 66 and the relative speed / distance calculation unit 69.

  In this way, the angle calculation unit 66 is provided with each FFT analysis result of the sum signal and the difference signal. Specifically, in the example of FIG. 10, the angle calculation unit 66 is configured to include an amplitude calculation unit 91 and an angle determination unit 92. Of these, the amplitude calculation unit 91 is provided with each FFT analysis result of the sum signal and the difference signal.

  Based on the FFT analysis results of the sum signal and the difference signal, the amplitude calculation unit 91 calculates the ratio of the signal strengths of the sum signal and the difference signal described above with reference to FIG. This is provided to the determination unit 92.

  The angle determination unit 92 holds, for example, the gain characteristic data of FIG. 4 in advance. The angle determination unit 92 determines the angle by comparing the data of FIG. Part 68.

  In the example of FIG. 10, a relative speed / distance calculation unit 69 is also provided. The relative speed / distance calculation unit 69 is also provided with each FFT analysis result of the sum signal and the difference signal. Therefore, the relative speed / distance calculation unit 69 calculates at least one of the relative speed and the distance to the detection target using each FFT analysis result of the sum signal and the difference signal, and the calculation result. Is provided to the forward target detection unit 68.

  In the present embodiment, it is assumed that the relative speed / distance calculation unit 69 calculates both the relative speed and the distance to the detection target. In this case, the calculation method of the relative speed and distance to the detection target is not particularly limited. For example, in the present embodiment, the following calculation method using the two-frequency CW method is applied.

  That is, in the example of FIG. 10, the two-frequency CW in which the frequencies f1 and f2 are switched in a time division manner as described above is adopted as the carrier wave of the transmission signal. That is, in the example of FIG. 10, it can be said that the transmission signal has two frequencies f1 and f2.

  Again, this transmission signal is reflected by the object to be detected, and the reflected signal is received by the monopulse radar 51 as a reception signal.

  At this time, if a relative velocity v exists between the monopulse radar 51 and the detection target, Doppler frequencies Δf1 and Δf2 are generated for the frequencies f1 and f2 of the transmission signal, respectively. The frequencies of the received signals are frequencies f1 + Δf1, f2 + Δf2, respectively.

  In other words, a signal obtained as a result of modulation using a two-frequency CW having two frequencies f1 + Δf1 and f2 + Δf2 as a carrier wave is a signal equivalent to the received signal.

  Therefore, the relative speed / distance calculation unit 69 calculates the Doppler frequency Δf1 or Δf2 from each FFT analysis result of the sum signal and the difference signal, and calculates the following equation (2) or equation (3). Thus, the relative velocity v of the detection target with respect to the monopulse radar 51 can be obtained.

v = c * [Delta] f1 / (2 * f1) (2)
v = c * Δf2 / (2 * f2) (3)
Note that c represents the speed of light.

  Further, the relative speed / distance calculation unit 69 calculates the difference between the phase φ1 of the Doppler signal having the Doppler frequency Δf1 and the phase φ2 of the Doppler signal having the Doppler frequency Δf2, that is, the phase difference φ1-φ2 from the sum signal. The distance L between the monopulse radar 51 and the detection target can be obtained by calculating from the FFT analysis results with the signal and performing the following equation (4).

  L = c * (φ1−φ2) / 4π * (f1−f2) (4)

  Such a calculation method is a calculation method based on the two-frequency CW method.

  The calculation result of the relative speed / distance calculation unit 69 to which such a calculation method using the two-frequency CW method is applied, that is, the relative speed v and the distance L with respect to the detection target are provided to the front target detection unit 68. Therefore, the front target detection unit 68 can determine whether or not the front target is detected in consideration of the relative speed v and the distance L in addition to the angle from the angle calculation unit 66.

  That is, in the example of FIG. 10, not only whether the angle is equal to or less than the threshold value, but also at least one of the relative speed v and the distance L is used as a determination criterion for the process of step S <b> 5 in the example of FIG. It becomes possible to use. Similarly, not only whether or not the angle is equal to or smaller than the threshold value, but also at least one of the relative speed v and the distance L can be used as a determination criterion for the process of step S10 in the example of FIG. become.

  As described above, the forward target detection unit 68 in the example of FIG. 10 can detect the forward target in consideration of not only the angle but also the relative speed v and the distance L, so that the target detection signal can be output more accurately. It becomes possible.

  In the above, one embodiment in the case where the above-described series of processes (or a part of the processes) is executed by hardware has been described.

  On the other hand, when the above-described series of processes (or a part of them) is executed by software, the monopulse radar 51 or a part thereof can be constituted by a computer as shown in FIG. 11, for example. .

  11, a CPU (Central Processing Unit) 101 executes various processes according to a program recorded in a ROM (Read Only Memory) 102 or a program loaded from a storage unit 108 to a RAM (Random Access Memory) 103. To do. The RAM 103 also appropriately stores data necessary for the CPU 101 to execute various processes.

  The CPU 101, ROM 102, and RAM 103 are connected to each other via a bus 104. An input / output interface 105 is also connected to the bus 104.

  The input / output interface 105 includes an input unit 106 including a keyboard and a mouse, an output unit 107 including a display, a storage unit 108 including a hard disk, and a communication unit 109 including a modem and a terminal adapter. It is connected. The communication unit 109 performs communication processing with other devices via a network including the Internet. Furthermore, the communication unit 109 transmits a transmission signal from the wide-angle transmission antenna 61-W or the narrow-angle transmission antenna 61-N, and causes the reception antennas 62-L and 62-R to receive a reception signal corresponding to the transmission signal. The transmission / reception processing of the

  A drive 110 is connected to the input / output interface 105 as necessary, and a removable medium 111 made up of a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is appropriately attached, and a computer program read from them is loaded. These are installed in the storage unit 108 as necessary.

  When a series of processing is executed by software, a program constituting the software executes various functions by installing a computer incorporated in dedicated hardware or various programs. For example, a general-purpose personal computer is installed from a network or a recording medium.

  As shown in FIG. 11, the recording medium including such a program is distributed to provide a program to the user separately from the apparatus main body, and a magnetic disk (including a floppy disk) on which the program is recorded. Removable media (package media) consisting of optical disks (including CD-ROM (compact disk-read only memory), DVD (digital versatile disk)), magneto-optical disks (including MD (mini-disk)), or semiconductor memory ) 111 as well as a ROM 102 on which a program is recorded and a hard disk included in the storage unit 108 provided to the user in a state of being incorporated in the apparatus main body in advance.

  In the present specification, the step of describing the program recorded on the recording medium is not limited to the processing performed in chronological order according to the order, but is not necessarily performed in chronological order, either in parallel or individually. The process to be executed is also included.

  The present invention can be applied not only to the monopulse radar 51 described above but also to devices and systems having various configurations. In addition, a system represents the whole apparatus comprised by a some processing apparatus and a process part here.

  That is, the technique of the present invention described above is a technique premised on application to a monopulse radar in order to facilitate comparison with a conventional monopulse radar. However, one of the objects of the present invention is that when a front object is detected, the detection is a correct detection for the presence of the front object, or one object at the left and right in front. It is to be able to accurately identify whether it is a false detection due to the existence of. Therefore, in order to achieve such an object, it is not particularly limited to the method of the present invention described above, and for example, the following method is sufficient.

  That is, using a plurality of antennas, a method of detecting an object existing ahead based on reception signals received by two or more of these antennas, each received signal received by two or more antennas The above-described object can be achieved by using the technique of identifying the position of the object using the method and confirming the presence of the object when the identified position is within a predetermined range. In other words, this technique is the technique of the present invention, and an example thereof is a technique premised on application to the monopulse radar described above.

  Therefore, the radio wave detection device to which the present invention is applied can be realized as the following device in addition to the monopulse radar 51 described above.

  That is, the monopulse radar 51 described above calculates an angle according to a monopulse method using two or more received signals corresponding to the first transmission signal, and determines the position of the object based on the angle. The monopulse radar 51 determines that the position of the object is within a predetermined range when the angle is equal to or smaller than the first threshold, and the directivity is narrower than the first transmission signal described above. Transmit the transmission signal of 2 and recalculate the angle according to the monopulse method using two or more reception signals corresponding to the second transmission signal, and confirm that the object exists when the angle is equal to or less than the second threshold In other cases, it was confirmed that it did not exist.

  However, the angle calculation method used for specifying the position of the object or confirming its existence is not particularly limited to the monopulse method, and for example, the CAPON method, the MUSIC method, the SPACE method, etc. can be adopted. .

  Furthermore, the confirmation method for confirming the object is not particularly limited to the method using the angle described above, and various methods can be employed.

  For example, it is possible to employ a confirmation method in which an effective transmission radio wave output is generated by changing the transmission output to control the angle range. That is, the angle range is widened in the first period corresponding to the period in which the wide-angle transmitting antenna is used, while the angle range is narrowed in the second period corresponding to the period in which the narrow-angle transmitting antenna is used. It is possible to adopt a confirmation method of confirming an object in the period of 2.

  For example, a confirmation method of controlling directivity by using a phase shifter can be adopted. That is, the directivity is widened in the first period corresponding to the period in which the wide-angle transmitting antenna is used, while the directivity is narrowed in the second period corresponding to the period in which the narrow-angle transmitting antenna is used. It is possible to adopt a confirmation method of confirming an object in the period of 2.

  In addition, for example, in the above-described distance radar such as the two-frequency CW sensor, when there are objects with the same relative speed v at a short distance and a long distance, the intermediate point is detected as the position of the target object. Therefore, it is possible to adopt a confirmation method in which, by changing the transmission power of the transmission antenna, the radio wave reaches only within a certain range, and whether or not the target exists in that range is confirmed. A method for grasping such a method from another viewpoint will be described later with reference to FIG.

  Furthermore, for example, a confirmation method in which an ultrasonic sensor or the like is provided instead of the narrow-angle transmission antenna and the object is confirmed based on the detection signal can be employed.

  For example, instead of a narrow-angle transmission antenna, a confirmation method can be employed in which a camera that captures the front is provided and the object is confirmed based on an image captured by the camera. In addition, the image here is a broad concept including not only a still image but also a moving image.

  Here, when a camera, an ultrasonic sensor, and the like are collectively referred to as an object confirmation unit instead of the narrow-angle transmission antenna, the following apparatus is also an embodiment of an apparatus to which the present invention is applied. .

  That is, the apparatus calculates an angle according to a monopulse method using two or more reception signals corresponding to the first transmission signal, and determines the position of the object based on the angle. Further, the apparatus determines that the position of the object is within a predetermined range when the angle is equal to or less than the first threshold, and the object confirmation unit confirms whether or not the object exists. An apparatus that executes such a series of processes is an embodiment of an apparatus to which the present invention is applied. Hereinafter, such an apparatus is referred to as a monopulse radar with an object confirmation unit.

  FIG. 12 is a functional block diagram showing functions of a monopulse radar with an object confirmation unit.

  In FIG. 12, the same reference numerals are given to the portions corresponding to FIG. The description of these portions has been described above with reference to FIG.

  The monopulse radar 201 with the object confirmation unit in the example of FIG. 12 is provided with an object confirmation unit 212 instead of the narrow-angle transmission antenna 61-N of the monopulse radar 51 of FIG. That is, since the monopulse radar 201 with the object confirmation unit in the example of FIG. 12 is provided with only the wide-angle transmission antenna 61-W, the transmission signal generation unit 63 is provided on the output side of the switching unit 64. Accordingly, an operation command issuing unit 211 is provided on the input side of the switching unit 64.

  Accordingly, in the example of FIG. 12, the switching unit 64 determines the output destination of the operation command from the operation command issuing unit 211 based on the control of the switching control unit 67 as the transmission signal generation unit 63 side and the object confirmation unit 212 side. And switch to one of the two sides.

  That is, when the output destination of the switching unit 64 is switched to the transmission signal generation unit 63 side, the operation command from the operation command issue unit 211 is issued to the transmission signal generation unit 63, and A transmission signal is output from the wide-angle transmission antenna 61-W, and the wide-angle detection described above with reference to FIG. 6 is performed.

  On the other hand, when the output destination of the switching unit 64 is switched to the object confirmation unit 212 side, an operation command from the operation command issuing unit 211 is issued to the object confirmation unit 212, and the object by the object confirmation unit 212 An object confirmation operation is performed. The processing result of the object confirmation unit 212, that is, the presence / absence of the object is provided to the front target detection unit 68. That is, in the monopulse radar 201 with the object confirmation unit in the example of FIG. 12, the object confirmation operation by the object confirmation unit 212 is performed instead of the narrow-angle detection performed in the monopulse radar 51 in the example of FIG. Is done.

  The other functional configuration of the monopulse radar 201 with the object confirmation unit in the example of FIG. 12 is basically the same as the functional configuration of the monopulse radar 51 of the example of FIG.

  A processing example of the monopulse radar 201 with the object confirmation unit having the functional configuration of FIG. 12 is shown in the flowchart of FIG.

  Note that the processing from step S41 to step S45 in FIG. 13 is basically the same as the processing from step S1 to step S5 in FIG.

  However, “switching to the wide-angle transmitting antenna” in the process of step S41 means that the output destination of the switching unit 64 in FIG. 12 is switched to the transmission signal generating unit 63 side.

  In step S45, when it is determined that there is a possibility that the front target exists, that is, in the present embodiment, when the angle is equal to or smaller than the threshold value, a switching command is issued from the front target detection unit 68 to the switching control unit 67. The process proceeds to step S46.

  In step S46, the switching unit 64 switches to the object confirmation unit 212 side in FIG. 12 based on the control of the switching control unit 67 that has received the switching command.

  Then, as described above, the operation command from the operation command issuing unit 211 is issued to the object confirmation unit 212, and the object confirmation operation by the object confirmation unit 212, that is, the confirmation operation of the front target is performed. The processing result of the object confirmation unit 212, that is, the presence or absence of the front target is provided to the front target detection unit 68.

  Therefore, in step S47, the front target detection unit 68 determines whether or not the object confirmation unit 212 has detected the front target.

  If it is determined in step S47 that the front target has not been detected, that is, if the processing result of the target object confirmation unit 212 is that there is no target, a switching command is issued from the front target detection unit 68. Issued to the section 67, the process returns to step S41. In step S41, the output destination of the switching unit 64 is switched to the transmission signal generating unit 63 side, and the processing from step S42 is executed.

  On the other hand, if it is determined in step S47 that the front target has been detected, that is, if the processing result of the object confirmation unit 212 is a result that the object exists, the front target detection unit 68 In S48, a target detection signal (target detection signal) is output.

  In step S49, the front target detection unit 68 determines whether or not the end of the process has been instructed.

  When it is determined in step S49 that the process has been instructed to end, the process of the monopulse radar 201 with the object confirmation unit ends.

  On the other hand, when it is determined in step S49 that the process has not been instructed yet, the forward target detection unit 68 issues a switching command to the switching control unit 67, and the process returns to step S41. . In step S41, the output destination of the switching unit 64 is switched to the transmission signal generating unit 63 side, and the processing from step S42 is executed.

  As described above, the monopulse radar 201 with the object confirmation unit to which the present invention is applied does not immediately output the target detection signal (target detection signal) when detecting the front target in the wide-angle detection, It is determined that it merely indicates the existence possibility, and further, an object (front target) confirmation operation by the object confirmation unit 212 is performed. Then, the monopulse radar 201 with the object confirmation unit outputs a target detection signal (target detection signal) only when the front target is actually confirmed by the object confirmation unit 212.

  That is, the monopulse radar 201 with the object confirmation unit performs the object (front target) confirmation operation by the object confirmation unit 212, and the wide-angle detection performed before that is because the front target actually exists. It is determined whether the detection is correct, or whether the detection is incorrect because there is another target in front of each of the left and right. The monopulse radar 201 with the object confirmation unit outputs a target detection signal (target detection signal) only when it is determined that the detection is correct.

  As a result, a signal processing unit (not shown) that performs processing for avoiding a collision between the host vehicle and another vehicle using the target detection signal (target detection signal) can accurately execute the processing. That is, it is possible to significantly reduce collision detection errors and the like.

  A series of processes (or a part of the processes) executed by the monopulse radar 201 with the target object confirmation unit, for example, the process according to the flowchart of FIG. 13 described above can be executed by hardware. It can also be executed by software.

  For example, although not shown, in the case of execution by hardware, a camera, an ultrasonic sensor, etc. are prepared as the object confirmation unit 212, and an operation command issuing unit 211 configured by an appropriate circuit is prepared, By mounting these on hardware having a similar configuration in FIG. 10, it is possible to realize the monopulse radar 201 with the object confirmation unit. The similar configuration in FIG. 10 refers to a configuration in which the arrangement of the switching unit 64, the transmission signal generation unit 63, and the like is changed to an arrangement corresponding to FIG.

  Also, for example, although not shown, when executing by software, a camera, an ultrasonic sensor, or the like is prepared as the object confirmation unit 212 and connected to the input / output interface 105 of FIG. By executing the processing of the unit 211, it is possible to realize the monopulse radar 201 with the object confirmation unit.

  Here, a wide angle detection and a narrow angle detection, which are one of the techniques of the present invention applied to the monopulse radar, will be considered from another aspect.

  As shown in FIG. 14, it is assumed that only the detection target object 5 exists at a position at an angle of 0 degrees. In this case, the detection angle of the monopulse type for wide-angle detection is 0 degree. The result of this wide-angle detection is the same as the result shown in FIG. 6 described above (the angle 0 degrees of the detection object 4 that is only a phantom because there are a plurality of detection objects 2 and 3).

  On the other hand, as shown in FIG. 15, the monopulse detection angle of the narrow angle detection in the case where only the detection target object 5 exists at the position of the angle 0 degree is also 0 degree. The result of this narrow angle detection is different from the result of the narrow angle detection in the case shown in FIG. 7 described above (the result that the angle cannot be detected).

  That is, in the monopulse type angle detection, there is only one detection target object (detection target object 5 in the example of FIG. 14) by only one angle detection result (wide-angle detection in the above example). It is practically impossible to judge whether the result is correct or whether the result is incorrect because there are a plurality of detection objects (two detection objects 2 and 3 in the example of FIG. 6).

  Therefore, in the monopulse radar to which the present invention is applied, the second angle detection is performed by changing the directivity of the transmission antenna (in the above example, switching to the narrow angle transmission antenna 61-N) (the above example). Then, a narrow-angle detection is performed, and the second detection result and the first detection result are compared, and it can be determined that they match (in the above-described example, it is shown in FIGS. 14 and 15). In the case), the first detection result is determined to be a correct result when only one detection target object (detection target object 5 in the example of FIG. 14) exists, while in other cases (described above) In the example (in the case shown in FIGS. 6 and 7), the first result is erroneous because there are multiple detection objects (two detection objects 2 and 3 in the example of FIG. 6). It can be determined that there is a possibility of a result.

  It should be noted that here, “when it can be determined that they match” is described as a result of the time interval between the first detection result and the second detection result being open, so during the open time, This is because the actual angle of the object to be detected may change, and there is a possibility that the detection result itself of each time may contain an error, so that it is rare that the detection results of both are exactly the same. However, for the sake of simplicity, “when it can be determined that they match” is simply expressed as “when they match”, and “other than that” is expressed as “when they do not match”.

  Also, the expression “possibly incorrect result” is because there is a possibility of a correct result. However, hereinafter, in such a case, for the sake of simplicity of explanation, it may be expressed as an erroneous result.

  That is, in the above-described example, when it is determined that the result of the first angle detection (wide angle detection) is correct by the second angle detection (narrow angle detection), the target detection signal is output and the second angle is detected. If it is determined by detection (narrow-angle detection) that the result of the first angle detection (wide-angle detection) is an error, it can be understood that the output of the target detection signal is prohibited.

  In summary, in order to determine the correctness of the result of the first angle detection when the directivity of the transmission antenna is set to the first directivity as monopulse angle detection, the following is determined. A technique may be adopted. That is, when the directivity of the transmitting antenna is changed from the first directivity to the second directivity, the second angle detection is performed, and the first result and the second result are compared. In this case, it is possible to adopt a method of determining that the first result is a correct result, and determining that the first result is an incorrect result when the two do not match.

  In other words, this method is a method when the above-described method of the present invention is viewed from another aspect. Hereinafter, this method is particularly referred to as a transmission antenna directivity change method.

  Note that changing the directivity of the transmission antenna from the first directivity to the second directivity means changing the directivity from the first directivity to the second directivity using one transmission antenna. The first transmission antenna having the first directivity and the second transmission antenna having the second directivity are separately prepared, and the first transmission antenna is used at the first time. The second concept is a concept including using a second transmitting antenna. Also, “changing from the first directivity to the second directivity” as used in the former means changing the half-value angle of the directivity of the transmission antenna from the first angle to the second angle (changing the characteristic). This is a concept including changing the direction (arrangement position) of the transmission antenna from the first direction to the second direction (changing the physical arrangement). The above-described example is an example of the latter case, in which the wide-angle transmission antenna 61-W corresponds to the first antenna, and the narrow-angle transmission antenna 61-N corresponds to the second antenna.

  This transmitting antenna directivity changing method is applicable not only to measurements such as monopulse angle detection but also to various other measurements. For example, the transmission antenna directivity changing method can be applied to the distance measurement of the two-frequency CW method.

  Therefore, distance measurement of the two-frequency CW method to which the transmitting antenna directivity changing method is applied will be described below.

  The two-frequency CW method distance measurement refers to the following measurement. That is, as described above, when a two-frequency CW having frequencies f1 and f2 is transmitted as a transmission signal and reflected by a detection object, a two-frequency CW having frequencies f1 + Δf1 and f2 + Δf2 is received as a reception signal. Received. Therefore, Doppler frequencies Δf1 and Δf2 are extracted from the received signal by frequency separation and extraction processing such as FFT, and phases φ1 and φ2 are extracted. Then, as shown in the above equation (4), the distance L of the detection target is measured using the difference between the extracted phases φ1 and φ2, that is, the phase difference φ1 to φ2.

  Here, for example, consider a case where there are a plurality of detection objects a to z.

  In this case, the transmission signal is reflected by each of the plurality of detection objects a to z, and a signal obtained as a result of combining the respective reflection signals becomes a reception signal.

  Considering that the Doppler frequencies Δf1 and Δf2 depend on the relative velocity v of the detection object, as is clear from the above-described equations (2) and (3), the plurality of detection objects a to z are Even if it exists, when the relative velocities v are different, the Doppler frequencies Δf1a to Δf1z are different from each other and the Doppler frequencies Δf2a to Δf are different for the reflected signals of the plurality of detection objects a to z. Each f2z is also different. Therefore, the phases φ1a to φ1z corresponding to the Doppler frequencies Δf1a to Δf1z can be extracted from the received signal, and the phases φ2a to φ2z corresponding to the Doppler frequencies Δf2a to Δf2z can also be extracted. . Therefore, correct measurement is possible by using the phase differences (φ1a−φ2a) to (φ1z−φ2z) for the distances La to Lz of the detection objects a to z, respectively.

  On the other hand, when the relative speeds v of the plurality of detection objects a to z are the same, the Doppler frequencies Δf1a to Δf1z and Δf2a to Δf2z all have the same Doppler frequencies Δf1 and Δf2. However, the phases φ1a to φ1z and the phases φ2a to φ2z are different from each other. Therefore, the same Doppler frequencies Δf1 and Δf2 and phases φ1 and φ2 corresponding to the same Doppler frequencies Δf1 and Δf2 are extracted from the received signal. The phases φ1 and φ2 are extracted from the phases φ1a to φ1z, The values are completely different from the phases φ2a to φ2z. As a result, the phase difference φ1−φ2 is also distorted, and the problem is that the distance L measured using the phase difference Φ1−φ2 where such a distorted error occurs is an incorrect result. Will do. In other words, the details will be described later with reference to FIG. 16, but even if a plurality of detection objects a to z having different distances actually exist, if the relative speeds v are the same, the detection object The object a thru | or z is not detected, but the problem that the false detection that one detection target object which is only a phantom exists in the distance L will be made occurs.

  In this case, this problem can be solved by applying the transmitting antenna directivity changing method to the distance measurement of the two-frequency CW method.

  Hereinafter, the principle of distance measurement of the two-frequency CW method to which the transmitting antenna directivity changing method is applied will be described with reference to FIGS. 16 to 19.

  16 to 19, the two-frequency CW sensor 401 performs a two-frequency CW method distance measurement to which the transmission antenna directivity change method is applied. The two-frequency CW sensor 401 includes a wide-angle transmission antenna 61-W (see FIGS. 16 and 18) and a narrow-angle transmission antenna 61-N (see FIGS. 17 and 19) similar to the monopulse radar 51. The wide-angle transmitting antenna 61-W and the narrow-angle transmitting antenna 61-N can be freely switched.

  First, as shown in FIG. 16, the two-frequency CW sensor 401 uses the wide-angle transmission antenna 61-W to perform the first distance measurement of the two-frequency CW method.

  Here, within the directivity range of the wide-angle transmitting antenna 61-W (that is, within the range of the angle θw referred to in FIG. 6 and the like), as shown in FIG. 16, the detection target 301 exists at the position of the actual distance L1. In addition, it is assumed that the detection target object 302 exists at the position of the actual distance L2.

  In this case, as described above, the transmission signal from the wide-angle transmission antenna 61-W is reflected by each of the detection target object 301 and the detection target object 302, and a signal obtained as a result of combining the respective reflection signals is received. The signal is received by the two-frequency CW sensor 401 as a signal.

  At this time, if the relative speeds v of the detection object 301 and the detection object 302 are the same, the Doppler frequencies Δf1-301 and Δf1-302 have the same Doppler frequency Δf1, and The Doppler frequencies Δf2-301 and Δf2-302 have the same Doppler frequency Δf2, but the phases φ1-301, φ1-302 and the phases φ2-301, φ2-302 are different from each other. Therefore, the same Doppler frequencies Δf1 and Δf2 and the corresponding phases φ1 and φ2 are extracted from the received signal, and this phase φ1 is the phases φ1-301 and φ1-302. Are different from each other, and the phase φ2 is also different from the phases φ2-301 and φ2-302. That is, the phase difference φ1-φ2 is also different from the phase difference (φ1-301) − (φ2-301) and the phase difference (φ1-302) − (φ2-302). Therefore, the result of distance measurement using such a phase difference φ1−φ2 is a distance L3 different from the distance L1 and the distance L2. In other words, the two-frequency CW sensor 401 cannot measure the distance L1 of the detection target 301 or the distance L2 of the detection target 302, and measures the distance L3 of one detection target 303 that is only a phantom. It ’s gone.

  However, the two-frequency CW sensor 401 detects whether the distance L3, which is the first measurement result, is the distance of the actually detected object, that is, the correct measurement result, or the detection with the same relative velocity v. It cannot be determined whether the measurement result is an erroneous result due to the presence of the object 301 and the detection object 302.

  Therefore, the two-frequency CW sensor 401 uses the narrow-angle transmitting antenna 61-N, that is, changes the directivity of the transmitting antenna, as shown in FIG. I do.

  In this case, the directivity range of the narrow-angle transmission antenna 61-N (that is, the angle θn in FIG. 7 and the like) is within the directivity range of the wide-angle transmission antenna 61-W (that is, the angle θw in the range of FIG. 6 and the like). 17), as shown in FIG. 17, only the detection target 302 existing at the position of the actual distance L2 is within the directivity range of the narrow-angle transmission antenna 61-N, and the detection target 301 is narrow. It falls outside the directivity range of the corner transmitting antenna 61-N. That is, the transmission signal from the narrow-angle transmission antenna 61 -N reaches the detection target 302 but does not reach the detection target 301.

  Accordingly, the transmission signal from the narrow-angle transmission antenna 61-N is reflected only by the detection target 302, and the reflected signal is received by the two-frequency CW sensor 401 as a reception signal. Thereby, Doppler frequencies Δf1-302 and Δf2-302 and phases φ1-302 and φ2-302 corresponding to the Doppler frequencies Δf1-302 and Δf2-302 are extracted from the received signal. As a result, the second distance measurement is performed using the phase difference (φ1-302) − (φ2-302), and the result is the distance L2.

  Accordingly, since the distance L2 that is the second measurement result and the distance L3 that is the first measurement result do not coincide with each other, the two-frequency CW sensor 401 includes a plurality of detection objects. Judged to be an incorrect result because it existed.

  On the other hand, within the directivity range of the wide-angle transmitting antenna 61-W (that is, within the range of the angle θw in FIG. 6 and the like), as shown in FIG. Only exist.

  Also in this case, the two-frequency CW sensor 401 first performs the first distance measurement of the two-frequency CW method using the wide-angle transmission antenna 61-W as shown in FIG.

  This time, the transmission signal from the wide-angle transmission antenna 61-W is reflected only by the detection target 302, and the reflected signal is received by the two-frequency CW sensor 401 as a reception signal. Thereby, Doppler frequencies Δf1-302 and Δf2-302 and phases φ1-302 and φ2-302 corresponding to the Doppler frequencies Δf1-302 and Δf2-302 are extracted from the received signal. As a result, the first distance measurement is performed using the phase difference (φ1-302) − (φ2-302), and the result is the distance L2.

  However, in the two-frequency CW sensor 401, whether the distance L2 which is the first measurement result is the distance of the actually detected object 302, that is, the correct measurement result, or the relative velocity v is the same. It cannot be determined whether the measurement result is incorrect due to the presence of a plurality of detection objects.

  Therefore, as shown in FIG. 19, the two-frequency CW sensor 401 uses the narrow-angle transmitting antenna 61-N, that is, changes the directivity of the transmitting antenna, and performs the second distance measurement of the two-frequency CW method. I do.

  Also in this case, the transmission signal from the narrow-angle transmission antenna 61-N is reflected only by the detection target 302, and the reflected signal is received by the two-frequency CW sensor 401 as a reception signal. Thereby, Doppler frequencies Δf1-302 and Δf2-302 and phases φ1-302 and φ2-302 corresponding to the Doppler frequencies Δf1-302 and Δf2-302 are extracted from the received signal. As a result, the second distance measurement is performed using the phase difference (φ1-302) − (φ2-302), and the result is the distance L2.

  Therefore, since the distance L2 that is the second measurement result matches the distance L2 that is the first measurement result, the two-frequency CW sensor 401 determines that the first measurement result is a correct result. be able to.

  The above series of processing examples can be summarized as shown in the flowchart of FIG.

  That is, in step S61, the two-frequency CW sensor 401 switches the transmission antenna to be used to the wide-angle transmission antenna 61-W.

  In step S62, the two-frequency CW sensor 401 transmits a transmission signal from the wide-angle transmission antenna 61-W.

  In step S63, the two-frequency CW sensor 401 determines whether or not a reception signal has been received.

  If it is determined in step S63 that the received signal has not been received, the process returns to step S61, and the subsequent processes are repeated. In this case, since it has already been switched to the wide-angle transmission antenna 61-W, the process proceeds to step S62 without substantially executing the process of step S61.

  On the other hand, when it is determined in step S63 that the received signal has been received, in step S64, the two-frequency CW sensor 401 calculates a distance from the received signal.

  That is, the first distance measurement is performed by the wide-angle transmitting antenna 61-W through steps S61 to S64. Therefore, in the next steps S65 to S68, the second distance measurement is performed by the narrow-angle transmission antenna 61-N.

  That is, in step S65, the two-frequency CW sensor 401 switches the transmission antenna to be used to the narrow-angle transmission antenna 61-N.

  In step S66, the two-frequency CW sensor 401 transmits a transmission signal from the narrow-angle transmission antenna 61-N.

  In step S67, the two-frequency CW sensor 401 determines whether or not a reception signal has been received.

  Here, when the received signal is not received, the second distance measurement cannot be performed. That is, the result of the second distance measurement is “not measurable” and does not match the result of the first distance measurement. Therefore, in such a case, it is determined as NO in step S67, the process is returned to step S61, and the subsequent processes are repeated.

  On the other hand, when it is determined in step S67 that the received signal has been received, in step S68, the two-frequency CW sensor 401 calculates a distance from the received signal.

  In step S69, the two-frequency CW sensor 401 determines whether there is a possibility of a phantom image distance by a plurality of front targets (detection objects).

  If the distance calculated in step S68 changes with respect to the distance calculated in step S64, that is, if the first distance measurement result and the second distance measurement result do not match, step S69. , It is determined that there is a possibility of a phantom image distance by a plurality of front targets (detection objects), the process is returned to step S61, and the subsequent processes are repeated.

  On the other hand, when the distance calculated by the process of step S68 does not change with respect to the distance calculated by the process of step S64, that is, the first distance measurement result and the second distance measurement result are one. If yes, it is determined in step S69 that there is no possibility of a phantom image distance by a plurality of front targets (detection objects), that is, the first distance measurement result is determined to be a correct result, The process proceeds to step S70. In step S70, the two-frequency CW sensor 401 outputs the distance.

  In step S71, the two-frequency CW sensor 401 determines whether or not an instruction to end the process is given.

  If it is determined in step S71 that the process has been instructed, the process of the two-frequency CW sensor 401 ends.

  On the other hand, if it is determined in step S71 that the process has not been instructed yet, the process returns to step S61, and the subsequent processes are repeated.

  Such a two-frequency CW distance measurement process of FIG. 20 can be executed by hardware or can be executed by software.

  When the two-frequency CW distance measurement process of FIG. 20 is executed by hardware, the two-frequency CW sensor 401 can take the configuration of FIG. 10 described above, for example. On the other hand, when the 2-frequency CW distance measurement process (or a part of the process) of FIG. 20 is executed by software, the 2-frequency CW sensor 401 or a part thereof is configured by the above-described computer of FIG. be able to.

  That is, the two-frequency CW sensor 401 can be configured as a device having a function of changing the directivity of the transmission antenna, like the monopulse radar 51.

  Of course, the two-frequency CW sensor 401 need not be configured as a device similar to the monopulse radar 51, and may be configured as a device similar to the monopulse radar 201 with the object confirmation object in FIG. It may be configured.

  In addition, the two-frequency CW sensor to which the transmission antenna directivity changing method is applied is not particularly limited to the two-frequency CW sensor 401. That is, the wide-angle transmission antenna 61-W and the narrow-angle transmission antenna 61-N are used as transmission antennas. It is not particularly limited to the mounted two-frequency CW sensor 401, and a two-frequency CW sensor having a function of changing the directivity of the transmission antenna is sufficient.

  Here, the function of changing the directivity of the transmission antenna is equipped with one transmission antenna and a function capable of changing the directivity, as well as a plurality of transmission antennas having different directivities, Includes a function to switch the antenna to be used. In addition, “changing the directivity” as used in the former means changing the direction (arrangement position) of the transmission antenna in addition to changing the half-value angle of the directivity of the transmission antenna (changing the characteristic) (physical It is also a concept that includes changing the general arrangement). The two-frequency CW sensor 401 is an example of a two-frequency CW sensor having the latter function.

  Furthermore, as an explanation of the transmitting antenna directivity changing method, it has been described that the directivity of the transmitting antenna is changed from the first directivity to the second directivity, but the number of changes in directivity is not particularly limited to two. That is, the directivity may be discretely changed three times or more, or the directivity may be continuously changed.

  In addition, the transmitting antenna directivity changing method is applied to the monopulse radar and the two-frequency CW sensor in the above-described example, but other methods using the Doppler signal for the reflected signal of the transmission signal to be detected (hereinafter referred to as Doppler). Any other type of radio wave detector can be applied.

  Furthermore, in other words, the transmitting antenna directivity changing method is replaced by a more general method as follows. That is, as a Doppler type radio wave detection, a method for determining the validity of the first detection result when the radio wave arrival range (detection range) of the transmitting antenna is set to the first range R1, specifically, The method is as follows. That is, the radio wave detection device performs the second detection by changing the reachable range (detection range) of the transmission antenna from the first range R1 to the second range R2. In this case, the radio wave detection device compares the first detection result with the second detection result, and makes the following determination from the comparison result. That is, when the first detection result and the second detection result coincide with each other, the region corresponding to the common part of the first range R1 and the second range R2 (hereinafter referred to as region R1 + R2) It is determined that there is an object to be detected. When the first detection result and the second detection result do not match (except when the second detection result is a result that the detection target does not exist), the radio wave detection device is in the second range R2. A region corresponding to a portion excluding the first range R1 (hereinafter referred to as region R2-R1) and a region corresponding to a portion excluding the second range R2 in the first range R1 (hereinafter referred to as region R2-R1). , Which are referred to as regions R1-R2), it is determined that one or more (that is, plural or singular) detection objects exist. When the second detection result is a result that the detection target does not exist, the radio wave detection apparatus determines that a single detection target exists in the region R1-R2. Hereinafter, this method is referred to as a transmission antenna detection range changing method.

  In this transmission antenna detection range changing method, the method of changing the detection range of the transmission antenna itself is not particularly limited. For example, a method of changing the angle of the detection range by changing the directivity of the transmission antenna is adopted. Alternatively, a method of changing the reach of the radio wave from the transmission antenna may be adopted.

  That is, an example of the transmission antenna detection range changing method in the case of adopting a method of changing the angle of the detection range by changing the directivity of the transmission antenna as a method of changing the detection range of the transmission antenna is described above. This is an antenna directivity change method.

  In this case, as described above, various techniques for changing the directivity of the transmission antenna can be adopted, and two antennas having different directivities (half-value angles) (for example, the above-described FIGS. A wide-angle transmission antenna 61-W, a narrow-angle transmission antenna 61-N, etc.) may be prepared, and a method of switching these two antennas may be adopted, or one transmission antenna may be adopted as shown in FIG. A method of changing (shifting) the directivity by using may be adopted.

  In other words, FIG. 21 shows an example in which a method of changing (shifting) the direction of one transmission antenna is adopted as a method of changing the detection range of the transmission antenna.

  In the example of FIG. 21, it is assumed that this method is applied to, for example, a radio wave detection device 511 that performs distance measurement by the Doppler method. The radio wave detection device 511 is attached to the front portion of the own vehicle 501, and other vehicles as the detection objects 301 and 302 run at the same relative speed v in front of the own vehicle 501. Suppose that

  In this case, as shown in the diagram on the left side of FIG. 21, the radio wave detection device 511 first sets the directivity of the transmission antenna (not shown) to the front, that is, sets the detection range as the first range R1. The first Doppler distance measurement is performed.

  In this case, since the detection objects 301 and 302 are traveling at the same relative speed v, as described with reference to FIG. 16, the radio wave detection device 511 calculates the distance L3a of the detection object 303a that is only a phantom. Will be measured. That is, the result of the first detection is a detection result that the detection object 303a, which is only a phantom, exists at the position of the distance L3a.

  However, the radio wave detection device 511 determines whether the detection object 303a detected for the first time is a single detection object that actually exists, that is, a correct detection result, or as shown in FIG. Therefore, it cannot be determined whether the detection target 301 and the detection target 302 having the same relative velocity v are illusions, that is, an erroneous detection result.

  Therefore, the radio wave detection device 511 shifts the directivity of the transmission antenna, that is, changes the direction (angle) of the detection range of the transmission antenna as the second range R2 as shown in the right side of FIG. Perform the second detection. In this case, compared with the first time, the balance of the radio waves irradiated from the transmission antenna to the actual detection objects 301 and 302 changes, and as a result, the second distance is the first distance L3a. It becomes a different distance L3b. That is, the second detection result is a detection result that the detection object 303b that is only an illusion exists at the position of the distance L3b.

  As described above, since the first detection result and the second detection result are different, and the detection result 303b is detected although it is an illusion in the second detection result, the radio wave detection device 511 has the region R2-R1 and the region R2 to R1. It is determined that one or more (that is, plural or singular) detection objects exist in both R1 and R2. That is, the radio wave detection device 511 determines that the first (and second) detection result is an unreliable and invalid result.

  Note that the processing performed by the radio wave detection device 511 after determining that the result is invalid is not particularly limited. For example, the radio wave detection device 511 may further shift the directivity of the transmission antenna to perform detection for the third time or more times, or based on the directivity of the transmission antenna. You may return and redo the first detection.

  On the other hand, although not shown, when the first and second detection results do not change, that is, when the measurement distances are substantially the same, there is a single detection object in the region R1 + R2. become. Accordingly, in such a case, the radio wave detection device 511 may perform the subsequent processing with the first or second detection result as positive.

  In contrast to the example of FIG. 21, FIG. 22 shows an example in which a method of changing the reach of radio waves from the transmission antenna is adopted as a method of changing the detection range of the transmission antenna.

  In the example of FIG. 22, it is assumed that such a method is applied to, for example, a radio wave detection device 512 that performs distance measurement by the Doppler method. The radio wave detection device 512 is attached to the front portion of the own vehicle 501, and other vehicles as detection objects 301 and 302 run at the same relative speed v in front of the own vehicle 501. Suppose that

  In this case, as shown in the diagram on the left side of FIG. 22, the radio wave detection device 512 first sets the radio wave arrival distance from the transmission antenna (not shown) as a long distance, that is, sets the detection range to the first range. As R1, the first Doppler distance measurement is performed.

  In this case, since the detection objects 301 and 302 existing in the first range R1 are traveling at the same relative speed v, the radio wave detection device 512 is only an illusion as described with reference to FIG. The distance L3 of the detection target object 303 will be measured. That is, the result of the first detection is a detection result that the detection object 303 that is only an illusion exists at the position of the distance L3.

  However, the radio wave detection apparatus 512 determines whether the detection object 303 detected for the first time is a single detection object that actually exists, that is, a correct detection result, or is shown in FIG. Thus, it cannot be determined whether the detection target 301 and the detection target 302 having the same relative velocity v are illusions, that is, whether the detection result is incorrect.

  Therefore, as shown in the right side of FIG. 22, the radio wave detection device 512 reduces the transmission power of the transmission antenna to reduce the radio wave arrival distance from the transmission antenna, that is, the detection. The second detection is performed with the range as the second range R2. In this case, in the example of FIG. 22, the radio wave from the transmission antenna does not reach the detection target 301. As a result, the second distance is a distance L2 different from the first distance L3, that is, the detection target 302. Is the actual distance L2. That is, the second detection result is a detection result that the detection target object 302 exists at the position of the distance L2.

  As described above, since the first detection result and the second detection result are different, and the detection target 302 is detected in the second detection result, the radio wave detection apparatus 512 includes the region R2-R1 and the region R1-R2. It is determined that there may be one or more (that is, plural or singular) objects to be detected. That is, the radio wave detection device 512 determines that the first (and second) detection result is an unreliable and invalid result.

  Note that the processing performed by the radio wave detection device 512 after determining that the result is invalid is not particularly limited. For example, the radio wave detection device 512 may further reduce the reach of the radio wave from the transmission antenna to perform the third detection or the number of detections more than that, or from the transmission antenna. It is also possible to restore the first radio wave arrival distance and redo the first detection.

  On the other hand, although not shown, when the first and second detection results do not change, that is, when the measurement distances are substantially the same, there is a single detection object in the region R1 + R2. become. Therefore, in such a case, the radio wave detection device 512 may perform subsequent processing with the first or second detection result as positive.

  As described above, the radio wave detection device 511 in FIG. 21 and the radio wave detection device 512 in FIG. 22 have been described as examples of the Doppler radio wave detection device to which the transmission antenna detection range changing method of the present invention is applied. However, the transmission antenna detection range changing method of the present invention is applicable to any Doppler type radio wave detection device. Therefore, a processing example of the Doppler radio wave detection apparatus to which the transmission antenna detection range changing method of the present invention is applied will be described more generally with reference to the flowchart of FIG.

  That is, in step S91, the radio wave detection device switches the detection range of the transmission antenna to the first range R1.

  In step S92, the radio wave detection device transmits a transmission signal from the transmission antenna.

  In step S93, the radio wave detection device determines whether or not a reception signal has been received.

  If it is determined in step S93 that the received signal has not been received, the process returns to step S93, and the subsequent processes are repeated. In this case, since the detection range of the transmission antenna has already been switched to the first range R1, the process of step S91 is not substantially executed, and the process proceeds to step S92.

  On the other hand, when it is determined in step S93 that the received signal has been received, in step S94, the radio wave detection device calculates a detection determination amount from the received signal.

  Here, the detection judgment amount refers to the distance when the radio wave detection device performs distance measurement such as a two-frequency CW sensor, and the radio wave detection device performs angle measurement such as a monopulse sensor. In the case of an angle.

  That is, the first detection using the first range R1 as the detection range is performed in steps S91 to S94. Therefore, the second detection using the second range R2 as the detection range is performed in the following steps S95 to S99.

  That is, in step S95, the radio wave detection device switches the detection range of the transmission antenna to the second range R2.

  In step S96, the radio wave detection device transmits a transmission signal from the transmission antenna.

  In step S97, the radio wave detection device determines whether a reception signal has been received.

  Here, when the received signal is not received, the second detection judgment amount cannot be calculated. That is, the second detection result is a result of “no detection object exists” and does not coincide with the first detection result. Therefore, in such a case, it is determined as NO in step S97, and the process proceeds to step S98. In step S98, the radio wave detection device outputs a detection signal indicating that a detection target exists in the region R1-R2. Thereby, the process proceeds to step S103. However, the processing after step S103 will be described later.

  On the other hand, when it is determined in step S97 that the received signal has been received, in step S99, the radio wave detection device calculates a detection determination amount from the received signal.

  In step S100, the radio wave detection device compares the detection determination amount (second detection result) calculated in step S99 with the detection determination amount (first detection result) calculated in step S94. Thus, it is determined whether or not the detection judgment amount has changed.

  When the detection judgment amount calculated in step S99 does not change with respect to the detection judgment amount calculated in step S94, that is, when the first and second detection results match, In step S100, it is determined as NO, and the process proceeds to step S101. In step S101, the radio wave detection device outputs a detection signal indicating that a detection target exists in the region R1 + R2. Thereby, the process proceeds to step S103. However, the processing after step S103 will be described later.

  On the other hand, when the detection judgment amount calculated in step S99 changes with respect to the detection judgment amount calculated in step S94, that is, when the first and second detection results do not match. As described above, it is determined that one or more (that is, plural or singular) detection objects exist in both the region R2-R1 and the region R1-R2. Therefore, in such a case, it is determined as YES in the process of step S100, and the following process of step S102 is executed. That is, in step S102, the radio wave detection device outputs an error signal indicating that determination is impossible.

  In this manner, when any one of steps S98, S101, and S102 is executed, the process proceeds to step S103. In step S103, the radio wave detection device determines whether an instruction to end the process is given.

  In step S103, when it is determined that the end of the process has been instructed, the process of the Doppler type radio wave detection apparatus ends.

  On the other hand, if it is determined in step S103 that the process has not been instructed yet, the process returns to step S91 and the subsequent processes are repeated.

  The processing of the Doppler type radio wave detection apparatus of FIG. 23 can be executed by hardware or can be executed by software.

  When the processing of FIG. 23 is executed by hardware, the radio wave detection device can be configured as shown in FIG. 10, for example. On the other hand, when the process of FIG. 23 (or a part of the process) is executed by software, the radio wave detection device or a part thereof can be configured by the computer of FIG. 11 described above, for example.

  Regardless of the configuration, the distance measured by the two-frequency CW method can be adopted as the detection judgment amount, or the angle measured by the monopulse method can be adopted.

  Of course, the radio wave detection device does not need to be configured as a device having both functions of the monopulse type and the two-frequency CW method, and can be configured as a device having any one function or a device having other functions. .

  Further, as a description of the transmission antenna detection range changing method, the transmission antenna detection range has been described as being changed from the first range R1 to the second range R2, but the number of changes in the detection range is not particularly limited to two. That is, the detection range may be changed discretely three times or more, or the detection range may be changed continuously.

It is a figure explaining a monopulse type. It is a figure explaining a monopulse type. It is a figure explaining a monopulse type. It is a figure explaining a monopulse type. It is a figure explaining the problem which the conventional monopulse type radar has. It is a figure explaining the method of the monopulse type to which this invention is applied. It is a figure explaining the method of the monopulse type to which this invention is applied. It is a functional block diagram which shows the functional structural example of the monopulse type radar to which this invention is applied. It is a flowchart explaining the example of a process of the monopulse radar of FIG. It is a block diagram which shows the hardware structural example of the monopulse type radar to which this invention is applied. It is a block diagram which shows another example of the hardware constitutions of all or one part of the monopulse radar to which this invention is applied. It is a functional block diagram which shows the functional structural example of the monopulse radar with a target object confirmation part to which this invention is applied. It is a flowchart explaining the example of a process of the monopulse radar with a target object confirmation part of FIG. It is a figure explaining the method to which this invention is applied in contrast with FIG. It is a figure explaining the method to which this invention is applied in contrast with FIG. It is a figure explaining the distance measuring method of 2 frequency CW type to which the present invention is applied. It is a figure explaining the distance measuring method of 2 frequency CW type to which the present invention is applied. It is a figure explaining the distance measuring method of 2 frequency CW type to which the present invention is applied. It is a figure explaining the distance measuring method of 2 frequency CW type to which the present invention is applied. It is a flowchart explaining the distance measurement process example of 2 frequency CW type to which this invention is applied. It is a figure explaining the method to which this invention is applied. It is a figure explaining the method to which this invention is applied. It is a flowchart explaining the example of a process of the radio wave detection apparatus of the Doppler system to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conventional monopulse radar 2 Object to be detected 3 Object to be detected 4 Illusion detected erroneously as object to be detected 11 Transmitting antenna 12-L Receiving antenna 12-R Receiving antenna 51 Monopulse radar 61-W to which the present invention is applied Wide-angle transmitting antenna 61-N Narrow-angle transmitting antenna 62-L Receiving antenna 62-R Receiving antenna 63 Transmission signal generating unit 64 Switching unit 65-L Received signal extracting unit 65-R Received signal extracting unit 66 Angle calculating unit 67 Switching control unit 68 Forward target detection unit 69 Relative speed / distance calculation unit 71 2 frequency CW oscillation unit 72 Modulation unit 73 Amplification unit 81-L Sum signal generation unit 81-R Difference signal generation unit 82-L, 82-R Amplification unit 83-L , 83-R mixing unit 84-L, 84-R LPF unit 85-L, 85-R A / D conversion unit 86-L, 86-R F T 91 amplitude calculator 92 angle determining unit 101 CPU
102 ROM
103 RAM
104 Bus 105 Input / Output Interface 106 Input Unit 107 Output Unit 108 Storage Unit 109 Communication Unit 110 Drive 111 Removable Media 201 Monopulse Radar with Object Confirmation Unit 211 Operation Command Issuing Unit 212 Object Confirmation Unit 301 Detection Object 301 Detection Object 303 Illusion detected as an object to be detected 401 Two-frequency CW sensor 501 Own vehicle 511 Radio wave detection device 512 Radio wave detection device

Claims (8)

In a radio wave detection device that uses a plurality of antennas and detects an object existing ahead based on reception signals received by two or more of these antennas,
Position specifying means for specifying the position of an object using each received signal received by the two or more antennas;
A radio wave detection apparatus comprising: object detection means for confirming presence of the object when the position specified by the position specification means is within a predetermined range. The object detection means includes:
When the position specified by the position specifying means is within the predetermined range, the second directivity is narrow with respect to the first transmission signal corresponding to the received signal used by the position specifying means. Narrow-angle transmission means for transmitting a transmission signal;
The radio wave detection apparatus according to claim 1, further comprising: a confirmation unit configured to confirm the presence of the target object based on a signal reflected by the target object from the second transmission signal from the narrow-angle transmission unit. The plurality of antennas are:
A first antenna for transmitting the first transmission signal;
The radio wave detection device according to claim 2, further comprising: a second antenna serving as the narrow-angle transmission unit that transmits the second transmission signal. The position specifying means calculates an angle by a monopulse method, specifies the position of the object based on the angle,
The confirmation means calculates an angle by a predetermined method using each received signal when a signal obtained by reflecting the second transmission signal by the object is received by each of the two or more antennas, The radio wave detection apparatus according to claim 3, wherein presence of the object is confirmed based on a calculation result. When the position specified by the position specifying means is within a predetermined range, the transmitting antenna is switched to the second transmitting antenna, and after the confirmation of the presence of the object by the checking means is completed, The radio wave detection device according to claim 4, further comprising switching means for switching an antenna to the first transmission antenna. A speed distance calculating means for calculating at least one of a relative speed and a distance to the detection object using at least a part of each of the received signals received by two or more of the antennas;
The position specifying means further uses at least a part of the calculation result of the speed distance calculation means to specify the position of the object,
The radio wave detection device according to claim 2, wherein the confirmation unit further confirms the presence of the object by further using at least a part of a calculation result of the speed distance calculation unit. When the position specified by the position specifying means is within a predetermined range, the target detecting means confirms the presence of the target using a technique different from the technique applied to the position specifying means. The radio wave detector according to claim 1. In a detection method of a radio wave detection device that uses a plurality of antennas and detects an object existing ahead based on received signals received by two or more of these antennas,
Using each received signal received by the two or more antennas, identify the position of the object,
A detection method including a step of confirming the presence of the object when the specified position is within a predetermined range.

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