JP2017207418A - Monitoring system and monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a saturation of receivers, while increasing the maximum searching distance of a radar.SOLUTION: A monitoring system includes: a radar control part for controlling radar units arranged to face an area of a monitoring object; and a moving body detection part for detecting a moving body in the area of the monitoring object. The moving body detection part detects a position of the moving body when the moving body is detected in the area of the monitoring area. If the moving body is a non-scan object that avoids irradiation of radar beams of a radar unit, an estimated position after the predetermined time of the body of the non-scan object is calculated. The radar control part divides the scan area of the radar unit for detection into a plurality of scan areas, and defines the zone in which the frequency for irradiating the radar beams in the scan area is divided according to the number of scan areas as a time slot, and when the body of the non-scan object is detected, the scan area is allotted to the time slot according to the position of the body and the estimation position after the predetermined time of the body.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a monitoring system for detecting foreign matter existing in a monitoring area such as a runway using a radar.

  If foreign objects are present on the airport runway or taxiway, a serious accident may occur if the aircraft touches the foreign objects or the engine sucks the foreign objects. Therefore, foreign objects on the runway are monitored.

  In addition, when a patrol car runs on an expressway and there is a foreign object on the road, the road administrator performs a task of removing the foreign object. A foreign object detection technique used has been developed (see, for example, Patent Document 1).

  The transmission power of the radar is determined by the radar reflection cross section of the object to be detected and the maximum detection distance. The radar transmission power needs to be increased as the radar reflection cross section is smaller, and the radar transmission power needs to be increased as the maximum detection distance is longer.

  On the other hand, if the transmission power is large, the reflected power received by the radar receiver increases, and performance degradation due to saturation of the radar receiver cannot be ignored.

  At an airport, when an airplane having a large radar reflection cross section exists within the radar detection range, it is necessary to determine the transmission power so that the reflected power from the airplane does not exceed the saturation power of the radar receiver. The size of foreign objects assumed on airport runways and taxiways is about 3 cm, and the radar reflection cross section is small. For this reason, in the conventional technique, the transmission power is determined so as not to cause saturation of the receiver in the radar reflection cross-sectional area of 3 cm of foreign matter, and thus there is a restriction on the maximum detection distance.

JP-A-2015-194371

  There is a need for a monitoring system that detects foreign objects at an airport to increase the detection distance or the detection distance in order to ensure safety on the airport surface such as a taxiway and a parking lot as well as a runway. For example, the foreign matter size can satisfy the above-mentioned needs by setting the detection distance of about 3 cm to about 100 m and the detection distance of about 500 m or more. However, if the detection distance is increased five times, the transmission power increases about ten times.

  That is, when the radar has a maximum detection distance of 10 times the maximum detection distance of the conventional radar, the transmission power of the radar needs to be increased by 40 dB = 10000 times. In this case, if the reflected power received by the conventional radar from the airplane existing at a distance α from the radar is βdBm, the reflected power received by the radar having a maximum detection distance of 10 times from the airplane existing at the distance α from the radar is Becomes (β + 40) dBm.

  In the conventional radar, the reflected power is not so great even when a radar beam is irradiated on an airplane close to the radar. However, in the radar having a maximum detection distance 10 times that of the conventional example, the reflected power is 40 dB = 10000 times larger than that of the conventional radar. Therefore, there has been a problem that performance degradation occurs due to saturation of the receiver.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a technique for suppressing saturation of a receiver while increasing the maximum detection distance of a radar.

  The present invention relates to a radar unit arranged to face an area to be monitored, a moving object detection unit for detecting an object in the area to be monitored, a radar control unit for controlling the radar unit having a processor and a memory. The moving body detection unit detects a position of the object when detecting the object in the monitoring target region, and the object avoids irradiation of the radar beam of the radar unit. Whether or not it is a target, calculates a predicted position of the non-scan target object after a predetermined time, and the radar control unit detects the object by irradiating the radar beam. Is divided into a plurality of scanning areas, and a period obtained by dividing a period in which the radar beam is irradiated in the scanning area into a plurality of times according to the number of the scanning areas is defined as a time slot. When the moving object detection unit detects the non-scan target object in the monitoring target area, the scan area is set in the time slot according to the position of the object and a predicted position after a predetermined time of the object. assign.

  Therefore, the present invention can suppress the saturation of the receiver while increasing the maximum detection distance of the radar by scheduling the scanning area of the radar according to the detected position of the moving object.

1 is a block diagram illustrating an entire monitoring system according to a first embodiment of this invention. 1 is a functional block diagram of a monitoring system according to a first embodiment of this invention. It is a flowchart which shows a 1st Example of this invention and shows an example of the process performed in an image analysis part. It is a figure which shows 1st Example of this invention and shows an example of the table of an image database. It is a flowchart which shows a 1st Example of this invention and shows an example of the process performed in an image analysis part. It is a flowchart which shows a 1st Example of this invention and shows an example of the process performed by a radar control part. It is a flowchart which shows a 1st Example of this invention and shows an example of the scheduling process of a radar control part. It is a figure which shows a 1st Example of this invention and shows an example of the scanning area at the time of dividing the area which a radar unit scans in the circumferential direction. It is a figure which shows a 1st Example of this invention and shows an example of the time slot which allocates a scanning area. It is a figure which shows the 1st Example of this invention and shows an example of a scheduling table. It is a figure which shows the 1st Example of this invention and shows the other example of a scheduling table. It is a figure which shows a 2nd Example of this invention and shows an example of the scanning area at the time of dividing | segmenting the cover area which a radar unit covers in a perpendicular direction. It is a figure which shows a 3rd Example of this invention and shows an example of the scanning area at the time of dividing | segmenting the cover area which a radar unit covers into the vertical direction and the horizontal direction. It is a block diagram which shows the 1st Example of this invention and shows an example of a moving body detection apparatus. It is a block diagram which shows the 1st Example of this invention and shows an example of a structure of a radar control apparatus. It is a figure which shows the 1st Example of this invention and shows an example of an arrangement | positioning table.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that this embodiment is merely an example for realizing the present invention, and does not limit the technical scope of the present invention. In each figure, the same reference numerals are given to common configurations.

  The first embodiment relates to a monitoring system that monitors foreign objects on a road surface such as a runway, a highway, and a rail. For example, an accident may occur when an aircraft touches a foreign object while the foreign object remains on the runway surface, and monitoring is performed for the presence of the foreign object on the road surface. In addition, when a patrol car runs on a highway and there is a foreign object, removal is performed every day. As described above, it is important to monitor the foreign matter on the road surface, and a foreign matter detection technique using a camera or a radar for detecting the foreign matter has been developed.

  FIG. 1 is a block diagram illustrating the overall configuration of a monitoring system for a runway 1 according to the first embodiment. A plurality of camera units 102-1 to 102-m are arranged along the runway 1 at positions where the road surface of the runway 1 (or taxiway, parking lot) can be monitored, and the camera units 102-1 to 102-m are predetermined. A moving object detection device 103 that detects a moving object (such as an airplane or a maintenance vehicle) 2 having a large radar reflection cross-sectional area as a non-scanning object is installed based on the image data captured at the period of.

  A plurality of radar units 101-1 to 101-n are arranged along the runway 1, and the radar control device 104 detects foreign matter on the runway 1 based on the detection results from the radar units 101-1 to 101-n. Is installed. The radar control device 104 controls the radar units 101-1 to 101-n and displays the detection results based on the detection results of the moving object detection device 103.

  In the following description, the entire radar units 101-1 to 101-n are denoted by reference numeral 101 without "-". The same applies to the reference numerals of other components such as the camera units 102-1 to 102-m.

  The radar units 101 are arranged at predetermined intervals along the runway 1 in order to form a plurality of radar scanning areas (cover areas) 50-1 to 50-n on the runway 1. The camera unit 102 is arranged at a predetermined position where the moving body 2 can be detected to enter or leave the runway 1, for example, at a connection position between the runway 1 and a taxiway (not shown). Note that the cover area 50 indicates an area in which the radar unit 101 detects an object by irradiating a radar beam.

  FIG. 2 schematically shows a functional block diagram of the runway 1 monitoring system.

  Image data captured by the camera unit 102 at a predetermined cycle is transferred to the image analysis unit 111 in the moving object detection device 103. The moving object detection device 103 includes an image analysis unit 111 that compares image data with data in the image database 110 and analyzes the position of the moving object 2 and the like, and an image analysis unit 112 that analyzes reflected power of the moving object 2 and the like.

  FIG. 13 is a block diagram illustrating an example of the configuration of the moving object detection apparatus 103. The motion detection apparatus 103 includes a processor 60, a memory 62, a chip set 61 that connects the processor 60 and an I / O device, a storage device 63 that is connected to the chip set 61 and functions as an I / O device, and a network I / O. F64, the input-output device 65, and the signal processing part 66 are included.

  The network I / F 64 is connected to the radar control device 104 via the network 80. The input / output device 65 includes a display, a mouse, a keyboard, and the like. The signal processing unit 66 is connected to the camera unit 102 and acquires image data.

  The OS 62, the image analysis unit 111, and the image analysis unit 112 are loaded on the memory 62 and executed by the processor 60. An image database 110 that stores images to be compared with the moving object 2 and an arrangement table 5 that stores information on the radar unit 101 are loaded into the memory 62 and referred to by the image analysis unit 111 and the image analysis unit 112.

  The image analysis unit 111 and the image analysis unit 112 are loaded into the memory 62 as programs. The processor 60 operates as a functional unit that provides a predetermined function by performing processing according to a program of each functional unit. For example, the processor 60 functions as the image analysis unit 111 by performing processing according to the image analysis program. The same applies to other programs. Furthermore, the processor 60 also operates as a functional unit that provides each function of a plurality of processes executed by each program. A computer and a computer system are an apparatus and a system including these functional units.

  FIG. 15 is a diagram illustrating an example of the arrangement table 5. The arrangement table 5 is a table in which positions of the radar unit 101 and the camera unit 102 are set in advance. The X coordinate 52, Y coordinate 53, and Z coordinate 54 included in the entry of the arrangement table 5 may be three-dimensional coordinates such as longitude, latitude, altitude, and airport coordinates.

  FIG. 14 is a block diagram illustrating an example of the configuration of the radar control device 104. The radar controller 104 includes a processor 70, a memory 72, a chipset 71 that connects the processor 70 and an I / O device, a storage device 73 that is connected to the chipset 71 and functions as an I / O device, and a network I / F74, an input / output device 77, a signal processing unit 76, and a signal source 75 for supplying a predetermined signal to the radar unit 101 and the signal processing unit 76.

  The network I / F 74 is connected to the moving object detection device 103 via the network 80. The input / output device 77 includes a display, a mouse, a keyboard, and the like. The signal processing unit 76 is connected to the radar unit 101 and acquires received data.

  The memory 72 is loaded with the OS 12, the radar control unit 120, and the detection processing unit 123 and executed by the processor 70. A scheduling table 15 for controlling the radar unit 101 is stored in the memory 72.

  The radar control unit 120 and the detection processing unit 123 are loaded into the memory 72 as programs. The processor 70 operates as a functional unit that provides a predetermined function by performing processing according to a program of each functional unit. For example, the processor 70 functions as the radar control unit 120 by performing processing according to the radar control program. The same applies to other programs. Furthermore, the processor 70 also operates as a functional unit that provides each function of a plurality of processes executed by each program. A computer and a computer system are an apparatus and a system including these functional units.

  FIG. 3 is a flowchart illustrating an example of processing performed by the image analysis unit 111. When the image analysis unit 111 receives the image data from the camera unit 102, the image analysis unit 111 executes the process of FIG. 3 (S201).

  First, the image analysis unit 111 performs background difference extraction processing (S202). The background difference extraction process exists in the background image acquired in advance by comparing the observed image data with the background image registered in advance in the registration table 300 of the image database 110 for each camera unit 102. This is a process of extracting an object that is not performed.

  The image analysis unit 111 performs an image feature amount calculation process based on the obtained background difference (object image) (S203). In the image feature amount calculation processing, the image of the moving object 2 extracted by the image analysis unit 111 is divided into P pieces in the vertical direction and Q pieces in the horizontal direction, and luminance I (x, y) is used as the feature amount of each region. (X = 0... P-1, y = 0... Q-1). The image analysis unit 111 collates the obtained luminance I (x, y) result with an image registered in the registration table 300 of the image database 110 (S204).

  FIG. 4 is a diagram showing an example of a registration table 300 for image data held in the image database 110. The registration table 300 includes a type 301 for storing the type of the moving object 2, an image 302 for storing image data, a direction 303 for storing the direction of the moving object 2 in the image data, and the reflection of the radar beam emitted from the radar unit 101. The power 304 is included in one entry. Note that the direction 303 and the reflected power 304 of the moving object 2 are values measured or set in advance for each type 301 of the moving object 2. Note that the luminance I (x, y) of the image 302 may be calculated in advance and stored in the registration table 300.

  Next, the image analysis unit 111 has the highest similarity between the feature amount (luminance) obtained by the image feature amount calculation processing in step S203 of FIG. Is extracted as an image of the moving object 2. The similarity calculation method performed by the image analysis unit 111 can use SSD (Sum of Squared Difference) or SAD (Sub of Absolute Difference).

  When the similarity is calculated by SSD, the image analysis unit 111 divides the luminance I (x, y) of the image extracted in step S203 and the various images 302 into the same regions as I (x, y). The result of accumulating the difference from U (x, y) for which the luminance has been calculated is defined as similarity C. Specifically, the similarity C is calculated from the following equation (1).

  The image analysis unit 111 determines the moving object 2 having the similarity C equal to or higher than a predetermined threshold as a non-scanning target that avoids the irradiation of the radar beam. Further, the image analysis unit 111 refers to the registration table 300 of the image database 110 and acquires the direction 303 and the reflected power 304 corresponding to the image 302 extracted by collation.

  Next, the image analysis unit 111 performs an analysis process (S205). In the analysis processing, the moving object position (x1, y1, z1) to be detected is calculated from the position (direction 303) of the image extracted by the image analysis unit 111 and the scale ratio. The scale ratio is a ratio of the size of the moving object 2 extracted from the image data and the size of the image 302 in the registration table 300 of the image database 110. The moving object position (x1, y1, z1) is the center of the moving object 2 image.

  As for the moving object position, the image analysis unit 111 calculates the distance from the camera unit 102 to the moving object 2 based on the scale ratio of the image data, and the direction of the acquired image and the known camera unit 102 that captured the moving object 2 are known. The position (x0, y0, z0) may be obtained from the arrangement table 5 and calculated.

  The image analysis unit 111 acquires the coordinates of each radar unit 101 from the arrangement table 5, and calculates the distance L between the two points from the position (x2, y2, z2) and the moving object position (x1, y1, z1) of each radar unit. Is calculated by the following equation (2).

  Then, the image analysis unit 111 selects the radar unit 101 having the smallest distance L between the two points as the radar unit 101 that is close to the moving object 2 and holds the distance L between the two points as the moving object distance R.

  The image analysis unit 111 transmits the type of the moving object 2, the moving object position, the direction, the moving object distance R, and the reflected power calculated by the above processing to the image analysis unit 112 (S206).

  FIG. 5 is a flowchart illustrating an example of processing performed in the image analysis unit. This process is started when the process of FIG. 3 is completed.

  When the image analysis unit 112 of the moving object detection apparatus 103 receives the result from the image analysis unit 111 (S401), the image analysis unit 112 estimates the received power of the radar unit 101. The estimated value of the received power of the radar unit 101 is calculated by the image analysis unit 112 from the moving object distance R and the reflected power 304 obtained from the image analysis unit 111 (S402). Specifically, the estimated received power Pv is calculated by the following equation (3).

  In the above equation (3), Ptrx can be calculated using the transmission power, G the transmission / reception antenna gain, σ the reflected power 304, τ the transmitter duty cycle, and R the moving object distance. The reflected power (304) σ is a predicted value of the power of the radar beam reflected by the non-scanning target moving body 2.

  Next, the image analysis unit 112 predicts the movement amount of the non-scanning target moving object 2 from the position information and direction information of the non-scanning target moving object 2 obtained from the image analysis unit 111 and the past position information of the moving object 2 ( S403). This can be estimated from the difference between the past position information of the moving object 2 and the current position information. In simple terms, it is possible to estimate that the past and present travel distances will be equivalent to the future, and since the behavior is limited on Runway 1, the past travel results are stored in a database It is also possible to guess from the history.

  In addition, when the object detected by the image analysis unit 111 is the non-scan target moving body 2, the image analysis unit 112 predicts the predicted position after a predetermined time after the moving body 2 (for example, when the scanning of the cover area of the radar unit 101 ends) May be calculated.

  For the prediction of the moving amount, latitude and longitude information is calculated as predicted position information at two times, the radar scanning start time of the radar unit 101 and the radar scanning completion time. The radar control device 104 scans the radar beam at a predetermined cycle (for example, 2 seconds), and can also transmit a trigger indicating the start of scanning to the moving object detection device 103 at the timing of the start of scanning, for example. Alternatively, the clocks of the moving object detection device 103 and the radar control device 104 or the scan start timing may be synchronized at predetermined time intervals.

  The moving object detection device 103 determines the predicted position of the moving object 2 at the start of the radar scan in the cover area 50 and the end of the radar scan from the irradiation timing of the radar beam with a predetermined period, and the detected position information and orientation information of the moving object 2. The predicted position of the moving body 2 is calculated as moving body information. The image analysis unit 112 notifies the calculated moving object information (latitude at the start of scanning, longitude at the start of scanning, latitude at the end of scanning, longitude at the end of scanning) and the reflected power to the radar control unit 120 of the radar control device 104.

  The radar control unit 120 manages all the radar units 101, and each radar unit 101 manages the cover area 50 by dividing it into N scanning areas in units of scheduling (see FIG. 8A).

  The scanning area is not necessarily equal to the radar one-beam irradiation range, and is larger than the radar one-beam irradiation and narrower than the radar unit cover range. The radar control apparatus 104 manages the time when beam irradiation is completed in each scanning area obtained by dividing the cover area 50 as T, and manages the section (time) during which beam irradiation is performed in the divided scanning area as a time slot. When one radar unit 101 is the cover area 50 and the time (cycle) in which the beam irradiation of all the scanning areas is completed is Tall, Tall ÷ T = the number of time slots. For example, when the time T for completing the beam irradiation in one scanning area is T = 2 seconds and the time Tall for completing the beam irradiation in the cover area is 16 seconds, the number of time slots is 8. That is, the time slot is a time obtained by dividing the period in which the radar beam is irradiated in the cover area 50 into a plurality according to the number of scanning areas.

  FIG. 8A is a diagram illustrating an example in which the radar unit 101 divides a cover area 50 that irradiates a radar beam into circumferential scanning areas. In the illustrated example, one radar unit 101 has a semicircular cover area, and an example of N = 8 scanning areas # 1 to # 8 obtained by dividing the inside of the cover area into eight equal parts will be described.

  In this example, the radar control device 104 divides scanning areas # 1 to # 8 (701 to 708) in the circumferential direction, and performs irradiation control of the radar beam. This premise is based on the premise that the transmission antenna block 131 and the reception antenna block 133 form a narrow beam in the horizontal direction and a wide beam in the vertical direction, and irradiate the beam to scan the cover area. Note that the radar unit 101 of this embodiment is configured by a phased array radar or the like, as long as the positions of the scanning areas # 1 to # 8 and the order of the time slots for irradiating the beam can be changed as appropriate.

  The cover area from the radar unit 101 is divided into a plurality of fan-shaped scanning areas # 1 to # 8 (701 to 708). In this case, since the scanning area is divided into eight, the number of time slots is eight.

  FIG. 8B is a diagram illustrating an example of a time slot in which the radar unit 101 scans a radar beam. In the illustrated example, one time slot performs radar beam irradiation at intervals of 2 seconds, and scans the cover area in 16 seconds. The radar control device 104 assigns scanning areas # 1 to # 8 for performing beam irradiation for each of the time slots # 1 to # 8 according to the position information and the reflected power of the moving body 2 to be scanned.

  As will be described later, the radar control device 104 allocates one scanning area to one time slot and executes irradiation with a radar beam.

  FIG. 9 is a diagram showing an example of the scheduling table 15 in which the relationship between the scanning area for irradiating the radar beam and the time slot is set. The radar control unit 120 creates the scheduling table 15 of FIG. 9 for each of the radar units 101-1 to 101-n, and manages time slots, position prediction results, scheduling results, and transmission power.

  The scheduling table 15 includes a time slot number 151, a moving object position prediction result 152 that stores a scanning area corresponding to the predicted position of the moving object 2, a scheduling 153 that stores a scanning area for irradiating a radar beam, and an irradiation to the scanning area. The transmission power 154 of the radar beam to be transmitted is included in one entry.

  The moving body position prediction result 152 obtains the scanning start latitude, the scanning start longitude, the scanning end latitude, and the scanning end longitude from the moving body information, and the position (longitude, latitude) of the non-scan target moving body 2 in each time slot. And the scanning area including the estimated position of the moving object 2 is set as a moving object position prediction result 152. Alternatively, a scanning area including a line connecting the estimated position of the moving object 2 and the radar unit 101 may be used as the moving object position prediction result 152. That is, the case where the moving body 2 exists in the scanning area and the case where the moving body 2 exists on the extension of the scanning area may be handled equally. Note that when the predicted position of the moving object 2 to be scanned is far from the radar unit 101 beyond a predetermined threshold, the received power Pv is not saturated and may be excluded from the moving object position prediction result 152.

  FIG. 6 is a flowchart illustrating an example of processing performed by the radar control device 104. This process is executed when moving object information and reflected power are received from the moving object detection device 103.

  When information is input from the moving object detection device 103 (S501), the radar control unit 120 determines which scanning area of each radar unit corresponds to the moving object position to be scanned (S502).

  For example, in the radar control unit 120, the scan start latitude and the scan start longitude received from the image analysis unit 112 correspond to the area # 7 (707), and the scan end latitude and the scan end longitude are the area # 7. FIG. 9 shows the moving object position prediction result 152 in the case of 4 (704).

  The radar control unit 120 uses the area # 7 (707) for the predicted position of the moving object 2 in the time slots # 1 and # 2, the area # 6 (706) in the time slots # 3 and # 4, the time slots # 5 and # 4. 6 predicts area # 5 (705) and time slots # 7 and # 8 as area # 4 (704), and stores the result in the scheduling table 15 of FIG. Assuming a prediction error as the prediction result, a plurality of scanning areas may be predicted for one time slot number.

  Next, the radar control unit 120 performs radar beam irradiation scheduling (S503). FIG. 7 is a flowchart illustrating an example of the scheduling process. After starting the scheduling, the radar control unit 120 first selects the time slot # 1 that is the head of the time axis (S602).

  First, the radar control unit 120 refers to the moving object position prediction result 152 in the scheduling table 15 and extracts a scanning area group α in which the moving object 2 to be scanned is present in one scanning section (cover area) of the radar unit 101. (S603). In the example of FIG. 9, scanning areas # 4, # 5, # 6, and # 7 (704, 705, 706, and 707) where the moving body 2 is predicted to exist are applicable.

  Next, the radar control unit 120 extracts a scanning area group β in which the non-scanning moving object 2 does not exist in the currently selected time slot from the scanning area group α (S604). Since the current time slot # 1 is scheduled, the current time slot is # 1, and in the example of FIG. 9, it is estimated that the scanning area where the moving object 2 exists in the time slot # 1 is 707. β becomes scanning areas # 4, # 5, and # 6 (704, 705, and 706) excluding scanning area # 7 (707).

  Next, the radar control unit 120 determines whether there is an unallocated scanning area in the scanning area group β (S605), and if there is an unallocated scanning area in the scanning area group β, One of the scanning areas is allocated (S612). In the example of time slot # 1 in FIG. 9, the scanning areas # 4, # 5, and # 6 (704, 705, and 706) of the scanning area group β are all unallocated, and thus are one of the scanning areas # 6 (706) is assigned to the current time slot # 1.

  Next, the radar control unit 120 determines whether or not the time slot number is the same as the last time slot (S613), and if not, increments the time slot number (S614).

  In the example of time slot # 1 in FIG. 9, the time slot is incremented from # 1 to # 2. In the case of the last time slot, the scheduling process is terminated, and the process returns to the process of FIG. 6 (S611).

  The radar control unit 120 assigns from the scanning area group β until time slot # 4, assigns scanning area # 5 (705) in time slot # 2, and scans in time slot # 3. Area # 4 (704) is allocated, and scanning slot # 7 (707) is allocated in time slot # 4.

  Since there are no unallocated scanning areas in the scanning area group β after the time slot # 5, the radar control unit 120 selects the scanning area group γ in which there is no moving object 2 to be unscanned in one scanning section of the radar unit 101. Extract (S606).

  In the example of FIG. 9, scanning areas # 1, # 2, # 3, and # 8 (701, 702, 703, and 708) correspond. When there is an unallocated scanning area # in the scanning area group γ (S607), one of the scanning areas is allocated (S612). In the example of time slot # 5 in FIG. 9, since the scanning areas # 1, # 2, # 3, and # 8 (701, 702, 703, 708) are not assigned, the radar control unit 120 is one of the scanning areas. Allocation of a certain scanning area # 8 (708) is performed.

  Similarly, the radar control unit 120 assigns scanning area # 3 (703) in time slot # 6, assigns scanning area # 2 (702) in time slot # 7, and scan area # 1 (701) in time slot # 8. Assign. When the radar control unit 120 completes the scheduling up to time slot # 8, it completes the scheduling up to the final time slot (S613), and thus completes the scheduling process and returns to the process of FIG.

  Next, the radar control unit 120 returns to FIG. 6 and performs transmission power determination processing (S504). In step S504, the radar control unit 120 registers transmission power in the scheduling table 15 based on the moving object position prediction result 152 and the result of scheduling 153. However, in the example of FIG. 9, since there is no time slot for irradiating the radar beam to the moving object 2 to be scanned, the transmission power can be scanned at the maximum Tmax.

  The radar control unit 120 performs the above processing for each of the radar units 101-1 to 101-n, generates the scheduling table 15, and notifies the radar unit 101 (S <b> 505). The radar control unit 120 scans areas # 1 to # 8 within the area group γ where there is no non-scanning object when there is no non-scanning target moving body 2 in the monitoring target area (runway 1). Are sequentially assigned to time slots # 1 to # 8.

  Next, an example of the scheduling table 15 for limiting the transmission power of the radar unit 101 will be described with reference to FIG. In the example of FIG. 10, the moving object position prediction result 152 is the scanning area # 7 (707) in all the time slots # 1 to # 8, and the moving speed of the moving object 2 that is not to be scanned is slow or stationary. It becomes.

  The scanning area group α in which the non-scanning target moving object 2 exists becomes the scanning area # 7 (707), but the non-scanning target moving object 2 does not exist in the current time slot. Therefore, the radar control unit 120 scans the scanning areas # 1, # 2, # 3, # 4, # 5, # 6, # 8 (701, 702, 703) of the scanning area group γ where there is no moving object 2 to be scanned. 704, 705, 706, and 708) are sequentially assigned to time slots # 1 to # 7.

  Then, the radar control unit 120 eliminates the scan area group σ corresponding to the scan area group γ in the time slot # 8, so the scan area group σ in which the non-scan target moving object 2 exists in the current time slot # 8. Extract (S608). In the example of FIG. 10, the radar control unit 120 sets the scanning area group σ to scanning area # 7 (707). Since there is an unallocated scanning area # 7 in the scanning area group (S609), one of the scanning areas is allocated to the current time slot # 7 (S612). In the example of FIG. 10, since the radar beam is irradiated to the non-detection target moving body 2 at time slot # 8, the power of the radar unit 101 is reduced. The transmission power Tlow of the radar unit 101 is implemented by the following equation (4).

Transmission power Tlow = Tmax− (estimated reception power Pv calculated in S402
-Maximum received power Rmax of radar unit) (4)

  The transmission power Tlow is irradiated with a radar beam by reducing in advance the amount that the received power Pv reflected by the moving body exceeds the maximum power of the radar unit 101. In other words, the output of the radar beam is equal to or less than the transmission power obtained by subtracting the reflected power from the non-scan target object from the maximum received power of the radar unit 101. That is, the reflection power of the moving body 2 that is not to be scanned is limited to a range that does not exceed the maximum received power Rmax that is allowed by the radar unit 101.

  When the scheduling is completed, the radar control unit 120 transmits information in the scheduling table 15 and a message designating transmission power to the unit control units 130 of the radar units 101-1 to 101-n.

  When the radar unit 101 receives the message, it generates beam scanning according to the information (scheduling information) in the scheduling table 15 and transmission power control information at the next scanning timing, and notifies the transmission antenna block 131 for each time slot. Control.

  The transmitting antenna block 131 regularly arranges a plurality of antenna elements like an array antenna for performing beam control freely, and controls the antenna directivity by electrically controlling the amplitude and phase of the radiating elements. It is desirable to use an antenna that can be used. As the transmission signal, an FM-CW (Frequency Modulated-Continuous Wave) signal that transmits a continuous wave with a variable frequency generated by the signal source 121 is generated and transferred to the transmitter block 132. Since the FM-CW signal is generated and transmitted in the IF (Intermediate Frequency) band, the transmitter block 132 performs upsampling from the IF band to the RF (Radio Frequency) band, and transfers it to the transmitting antenna block 131. The radar unit 101 can realize desired transmission control by transmitting FM-CW according to the scheduling information described above.

  The reception antenna block 133 receives a signal reflected from the moving body and foreign matter on the runway 1 as a transmission signal (radar beam) of the radar unit 101. The scheduling information generated by the radar control unit 120 is also transmitted to the receiving antenna block 133.

  The reception antenna block 133 is preferably a separate unit in consideration of isolation from the transmission antenna 131, but antenna scanning control is performed in the same manner as the transmission antenna block 131. When the reception antenna block 133 receives the FM-CW signal according to the scheduling information, the reception result is transferred to the receiver block 134 together with the received antenna angle information. The receiver block 134 performs downsampling from the RF band to the IF band and transfers the signal to the signal processing unit 122.

  The signal processing unit 122 performs mixing with the transmission signal, and from the result obtained by performing FFT analysis on the obtained beat signal, the reception intensity and distance of the signal from the foreign object can be determined. The signal processing unit 122 transfers the determination result to the detection processing unit 123, and the detection processing unit 123 graphically displays the runway foreign object detection result together with the moving object detection result on the display of the input / output device 77 or the like. It is possible to support foreign object detection work on the road 1.

  As described above, according to the first embodiment, the radar control unit 120 divides the cover area of the radar unit 101 into a plurality of scanning areas, and the intrusion of the non-detected moving object 2 is predicted in the scanning area. Performs scheduling for each time slot so that radar beam irradiation is performed in a scanning area other than the scanning area. Then, when the radar control unit 120 irradiates a radar beam in a scanning area where the intrusion of the non-detection target moving body 2 is predicted, the radar control unit 120 reduces the transmission power and the reception power Pv of the receiver block 134 of the radar unit 101. Is controlled so as not to exceed the maximum allowable value. Accordingly, an object is to provide a technique for suppressing the saturation of the receiver block 134 while increasing the maximum detection distance of the radar unit 101.

  In the airport monitoring system shown in the first embodiment, a moving object (airplane, maintenance vehicle, etc.) having a large radar reflection cross-sectional area is set as a non-scanning target, and scanning of the radar beam is scheduled so as to avoid the non-scanning target. As a result of scheduling, when beam irradiation to a non-scan target is inevitable, saturation of the receiver block 134 is avoided by reducing transmission power from the radar.

  (1) The irradiation range of one scan of the radar unit 101 is divided into a plurality of scanning areas, and the irradiation time is divided into a plurality of time slots.

  (2) During one scan, it is estimated when (when time slot #T) and where (position of area #N) the non-scan target is present. The estimation result is held in the scheduling table 15.

  (3) Scheduling of the scanning area for irradiating the radar beam in the order of time slots.

  The scheduling is specifically as follows.

  Flow 1: First, the radar control unit 120 extracts a scanning area group α where the moving object 2 to be non-scanned exists within the scanning period. Next, from the scanning area group α, a scanning area group β in which no non-scan target exists in the current time slot is extracted. Next, an unallocated area in the scanning area group β is set as a scanning area in the current time slot.

  Flow 2: When there is no unassigned scanning area in the scanning area group β, the radar control unit 120 extracts a scanning area group γ in which no non-scanning target exists from other time slots. An unallocated scanning area in the scanning area group γ is set as a scanning area in the current time slot.

  Flow 3: The radar control unit 120 extracts a scanning area group σ in which a non-scan target exists in the current time slot when there is no unallocated scanning area in the scanning area group γ. Among the scanning area group σ, an unallocated scanning area is set as a scanning area in the current time slot.

  As a result of scheduling, when beam irradiation to a non-scan target is unavoidable, the transmission power of the radar is limited to the transmission power setting value− (reception power prediction value (reception power Pv) −maximum reception power of the radar unit). .

  By performing the flow 1 before the flow 2, the scanning area that may have a non-scan target in another time slot is preferentially given to the initial time slot in the scanning cycle as a scanning area. Therefore, the possibility of irradiating a non-scan target with a beam during one scan can be reliably reduced.

  In the first embodiment, an example in which the moving object detection device 103 uses an image of the camera unit 102 provided on the runway 1 is shown, but the present invention is not limited to this. For example, the coordinates of the moving object 2 detected by the airport surface detection radar ASDE (Airport Surface Detection Equipment) installed at the airport, position information transmitted by the aircraft (for example, ADS-B: Automatic Dependent Surveillance-Broadcast), etc. are acquired. Thus, the moving body 2 to be non-scanned may be detected on the runway 1 to be monitored.

  In the first embodiment, an example is shown in which the moving object detection device 103 and the radar control device 104 are configured separately, but a single device may be used. In this case, a monitoring device having a moving object detection unit and a radar control unit may control the radar unit 101 and the camera unit 102.

  Moreover, in the said Example 1, although the example which made the monitoring area | region the runway 1 of the airport was shown, it is not limited to this, If it is a surface which needs to detect a foreign material, such as a road and a track Good.

  FIG. 11 is a diagram illustrating an example of an area when the cover area covered by the radar unit 101 is divided in the vertical direction according to the second embodiment of the present invention. Other configurations are the same as those of the first embodiment.

  FIG. 11 shows an example in which the scanning area of the radar unit 101 is divided into eight parts in the vertical (Z-axis) direction. In this example, the scanning area # is divided in the vertical direction (801 to 808), and control is performed. This premise is that the transmission antenna block 131 and the reception antenna block 133 are narrow in the vertical direction and form a wide radar beam in the horizontal direction, and the scanning of the scanning area # is performed in the vertical direction by irradiating the radar beam.

  Even in this case, the scheduling algorithm extracts the scanning area groups α, β, γ, and σ according to FIG. 7 and assigns them sequentially to the time slots, so that the same effect as in the first embodiment can be obtained.

  FIG. 12 shows a third embodiment of the present invention, and shows an example of an area when the cover area covered by the radar unit 101 is divided in the vertical direction and the circumferential direction. Other configurations are the same as those of the first embodiment.

  FIG. 12 shows an example in which the scanning area is divided into 16 parts in the vertical direction and the circumferential direction. In this example, the scanning area is divided into a circumferential direction and a vertical direction (901 to 916), and control is performed. In this example, the transmission antenna block 131 and the reception antenna block 133 are narrow in the vertical direction and form a narrow beam in the horizontal direction, and the scanning area is sequentially scanned by irradiating the radar beam.

  Even in this case, the scheduling algorithm extracts the scanning area groups α, β, γ, and σ according to FIG. 7 and assigns them sequentially to the time slots, so that the same effect as in the first embodiment can be obtained.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments are described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, any of the additions, deletions, or substitutions of other configurations can be applied to a part of the configuration of each embodiment, either alone or in combination.

  Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. In addition, each of the above-described configurations, functions, and the like may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files for realizing each function can be stored in a memory, a hard disk, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

  Further, the control lines and information lines are those that are considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

101-1 to 101-n Radar unit 102-1 to 102-m Camera unit 103 Moving object detection device 104 Radar control device 110 Image database 111 Image analysis unit 112 Image analysis unit 120 Radar control unit 130 Unit control unit 132 Transmitter block 134 Receiver block

Claims (9)

A radar unit placed facing the monitored area;
A moving object detection unit for detecting an object in the region to be monitored;
A radar control unit that has a processor and a memory and controls the radar unit;
The moving object detection unit includes:
When an object is detected in the region to be monitored, the position of the object is detected, it is determined whether or not the object is a non-scanning target that avoids irradiation of a radar beam of a radar unit, and the non-scanning target object To calculate the predicted position after a predetermined time,
The radar control unit
A section in which a scanning area of the radar unit that irradiates the radar beam to detect an object is divided into a plurality of scanning areas, and a period in which the radar beam is irradiated in the scanning area is divided into a plurality of sections according to the number of scanning areas. Is a time slot,
When the moving object detection unit detects the non-scan target object in the monitoring target area, the scan area is allocated to the time slot according to the position of the object and a predicted position after a predetermined time of the object. A monitoring system characterized by that. The monitoring system according to claim 1,
The radar control unit
When there is a scanning area where the non-scan target object exists within the period of irradiation of the radar beam, the scan area is defined as a scan area group, and the scan area within the scan area group includes the non-scan target. A monitoring system characterized by assigning to a time slot that does not. The monitoring system according to claim 2,
The radar control unit
When there is a scanning area where the non-scan target object exists within the period of irradiation of the radar beam, the scan area is defined as a scan area group, and the scan area within the scan area group includes the non-scan target. When the time slot cannot be assigned, the scanning area in which the non-scan target object exists is assigned to the time slot to reduce the output of the radar beam. The monitoring system according to claim 3,
The radar control unit
In the time slot in which the radar beam is irradiated in the scanning area where the non-scan target object exists, the radar beam is within a range where the reflected power of the non-scan target object does not exceed the maximum received power allowed by the radar radar unit. Monitoring system characterized by limiting the output of the. The monitoring system according to claim 1,
The radar control unit
A monitoring system that divides a plurality of scanning areas in a circumferential direction of a scanning area of the radar unit that detects an object by irradiating a radar beam. The monitoring system according to claim 1,
The moving object detection unit includes:
Including a camera disposed facing the monitoring target area, detecting the object from image data captured by the camera, and comparing the image data with a pre-registered image of the non-scan target object A characteristic surveillance system. A radar control unit that controls a radar unit that has a processor and a memory and faces a monitoring target region, and a moving object detection unit that detects an object in the monitoring target region monitors the monitoring target region. A monitoring method,
When the moving object detection unit detects an object in the monitoring target area, it detects the position of the object, and determines whether the object is a non-scanning target that avoids irradiation of a radar beam from a radar unit. A first step of calculating a predicted position of the non-scan target object after a predetermined time;
The radar control unit divides a scanning area of the radar unit that detects an object by irradiating a radar beam into a plurality of scanning areas, and a period in which the radar beam is irradiated in the scanning area according to the number of the scanning areas. A second step of assigning the scanning area to the time slot, with the section divided into a plurality of time slots,
The second step includes
When the moving object detection unit detects the non-scan target object in the monitoring target area, the scan area is allocated to the time slot according to the position of the object and a predicted position after a predetermined time of the object. A monitoring method characterized by that. The monitoring method according to claim 7, comprising:
The second step includes
When there is a scanning area where the non-scan target object exists within the period of irradiation of the radar beam, the scan area is defined as a scan area group, and the scan area within the scan area group includes the non-scan target. A monitoring method characterized by assigning to a non-performing time slot. The monitoring method according to claim 8, comprising:
The second step includes
When there is a scanning area where the non-scan target object exists within the period of irradiation of the radar beam, the scan area is defined as a scan area group, and the scan area within the scan area group includes the non-scan target. When the time slot cannot be assigned, a scanning area in which the non-scanning object is present is assigned to the time slot to reduce the output of the radar beam.

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