JP3613521B2 - Target detection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, for example, is a system that detects a target such as an aircraft on the airport surface and displays its position on a display screen when controlling an aircraft or vehicle traveling in an airport. To Related.
[0002]
[Prior art]
Conventionally, in order to ensure the safe and smooth operation of aircraft that take off and land at airports, or aircraft and vehicles that run in airports, airport surface detection equipment (hereinafter referred to as “ASDE”), airport surveillance radars. (Airport Surveillance Radar. Hereinafter referred to as “ASR”) and secondary surveillance radar (Secondary Surveillance Radar. Hereinafter referred to as “SSR”) to detect and control a target is known.
[0003]
For example, Japanese Patent Laid-Open No. 08-146130 discloses an example of such a control system. FIG. 16 is a block diagram showing the configuration of the airport surface ground control system. As shown in the figure, this system includes a radar antenna 1 that detects a target on an airport surface, a transmitter 2 that transmits a radio wave via the radar antenna 1, and a radio wave reflected by the target and returned to the radar antenna 1. An ASDE 101 including a receiver 3 that receives the signal via the circulator 8 and a circulator 8 that switches a transmission / reception direction of the radio wave, an ASDE target detection device 4 that detects a target based on the received radio wave (hereinafter referred to as radar video), and radar target detection An identification code adding device 5 for adding an identification code such as a call sign to the target detected by the device 4, a high-function display device 6 for displaying the position of the detected target, and an aircraft in the airspace around the airport are monitored. , ASR / SSR14 for control and detection of target and predetermined beacon code from received radio wave of ASR / SSR14 ASR / SSR target detection device 15, flight information processing device (Flight Plan Processing system hereafter) 18 that transmits flight information such as call signs of each aircraft, and a spot surrounding the ASDE radio blind spot An optical sensor 20, a blind target detection device 21 that detects aircraft position information based on information from the optical sensor 20, an SSR mode transceiver 24 that receives a mode S signal of an SSR mode S-equipped aircraft, and an SSR A vehicle positioning GPS 25 that detects a target position and a beacon code from a mode S signal, and a GPS (Global Navigation Positioning System) mounted on a vehicle that monitors and manages the interior of the airport. A transceiver 28, a vehicle target detection device 29 for calculating the position of the vehicle on the airport surface, Aircraft dynamic, configured by a collision prediction apparatus 32 for generating an alarm for collision prevention performs collision prediction by the prediction of the movement position of the vehicle.
[0004]
Next, the operation of this airport surface ground control system will be described. The radar antenna 1 emits a transmission radio wave 10 from the transmitter 2 into the space as a radio wave 7 via a circulator 8. The emitted radio wave 7 is reflected by a target such as an aircraft and received again by the radar antenna 1, and is input as a radio wave 7 to the receiver 3 as a received radio wave 9 via a circulator 8. The receiver 3 amplifies and frequency-converts the weak aircraft signal to generate the radar video 11. The radar video 11 is input to the ASDE target detection device 4. The ASDE target detection device 4 detects the position of the aircraft from the radar video 11. The detection result is input to the identification code adding device 5 as ASDE target detection position data 12.
[0005]
In addition, the ASR / SSR radar video 16 from the ASR / SSR 14 is input to the ASR / SSR target detection device 15, and the ASR / SSR target detection device 15 determines the airspace around the airport from the input ASR / SSR radar video 16. Detect the position of the aircraft in flight and the beacon code. The detection result is input to the identification code adding device 5 as ASR / SSR target detection data 17. Flight plan data 19 transmitted from the FDP 18 is also input to the identification code adding device 5.
[0006]
Further, the blind area where the ASDE radio wave does not reach such as around the spot on the airport surface is photographed by the optical sensor 20, and the image data 22 is input to the blind target detection device 21. The blind target detection device 21 performs image processing on the image data 22 to detect a target. The detection result is input to the identification code adding device 5 as blind target position data 23.
[0007]
The identification code adding device 5 automatically matches the beacon code detected by the ASR / SSR target detection device 15 with the beacon code described in the flight plan data 19 transmitted from the FDP 18 to automatically call the aircraft. And so on. In addition, the radar coverage area of ASR / SSR 14 and ASDE and the overlapping area of the monitoring area of ASDE and optical sensor 20 are provided, and the call sign added by ASR / SSR 14 is calculated by calculating the respective position correlations. Maintain continuously from area to optical sensor area.
[0008]
The SSR mode S signal 26 received by the SSR mode S transceiver 24 is input to the position rating device 25, and the position rating device 25 detects the target position based on the signal. An aircraft equipped with SSR mode S can use the SSR mode S position data 27 obtained thereby to make an individual question and answer, and beacon from a pre-departure state where there is no radio wave interference and is parked at a spot position. You can get the code. Further, by collating with the beacon code of the flight plan data 19 obtained by the FDP 18, the call sign can be automatically added.
[0009]
The vehicle-mounted GPS transmitter 28 mounted on various vehicles transmits the GPS position of the vehicle as GPS position data 30 to the vehicle position detection device 29 by radio waves. The vehicle position detection device 29 calculates a vehicle position converted into airport plane coordinates, and inputs the calculated vehicle position information 31 to the identification code adding device 5. Thereby, an identification code such as a vehicle number is also added to the vehicle.
[0010]
The target information to which the identification code is added by the identification code adding device 5 is input to the high function display device 6 and the collision prediction device 32 as the aircraft identification display data 13. The high function display device 6 displays the detected target as a symbol on the map indicating the airport surface based on the inputted aircraft identification display data 13. On the other hand, the collision prediction device 32 grasps the relative relationship of the target positions from the inputted aircraft identification display data 13, and predicts the future position of each target based on the relation. The necessity of a collision prevention alarm is calculated from the prediction result, and is transmitted to the high function display device 6 as the collision prediction data 33. The high function display device 6 displays a warning about a target predicted to be collided on the screen together with the symbol.
[0011]
[Problems to be solved by the invention]
In order for such a system to be effective, it is essential to accurately detect the target. However, in general, target detection is performed by determining the presence or absence of a target based on whether or not a signal representing radar echo exceeds a predetermined threshold. Therefore, reflection from a target other than the target due to the influence of snow or rain (hereinafter referred to as clutter). ) Becomes stronger, the detection accuracy may temporarily deteriorate.
[0012]
For this reason, conventionally, various methods for accurately detecting a target even under adverse conditions have been studied. For example, Japanese Patent Laid-Open No. 10-142329 proposes a method of suppressing clutter contained in a radar signal by feedback-controlling the input / output characteristic curve of an amplifier that amplifies the received radar signal based on the number of erroneous targets. ing. However, such a method only adjusts the amplitude of the signal in order to make it easier to detect the target. Therefore, although the detection rate is improved, the target cannot be detected with 100% accuracy, and there is always a limit. And in bad conditions that exceed that limit, there is a possibility that the target may be misidentified.
[0013]
The only effective countermeasure against this is that the air traffic controller correctly recognizes the limitations of the system, and does not make a judgment easily only by displaying the system. However, even though the system was introduced to improve the efficiency of air traffic control, it must always be carefully judged while doubting the system, which could increase the burden on the air traffic controller and reduce the efficiency. There is.
[0014]
The present invention has been made to solve such problems, and performs efficient monitoring of aircraft and vehicles without increasing the burden on air traffic controllers, etc., and air traffic controllers etc. overtrust the system. The purpose is to ensure traffic safety by taking appropriate measures as necessary.
[0015]
[Means for Solving the Problems]
The present invention is a target detection system that detects a target based on whether or not a signal value representing radar echo exceeds a predetermined threshold, and displays the position of the target on a display screen.
Radar coverage The predetermined observation area is memorized, and it is discriminated whether the area being swept is the observation area or not by the input signal from the radar. Clutter factor investigation means for investigating clutter factor,
By the clutter factor investigation means Only the radar echoes in the observation area are extracted, and the radar echoes in the observation area in a situation where no pre-stored clutter occurs are compared with the extracted radar echoes in the observation area. Clutter level determining means for determining the level;
Outputs information indicating the reliability of the target detection result based on the clutter level determined by the clutter level determination means. When the clutter level becomes high, a warning is displayed. A target detection system comprising: a reliability information output unit.
[0016]
More particularly, the present invention comprises A / D conversion means for digitizing an analog signal representing radar echo,
Recording means for temporarily recording a radar echo signal digitized by the A / D conversion means;
A target extraction means for comparing the value of the signal recorded in the recording means with a predetermined threshold to determine a signal that exceeds the threshold as a signal representing a target, and for extracting a target;
Radar coverage The predetermined observation area is memorized, and it is discriminated whether the area being swept is the observation area or not by the input signal from the radar. Clutter factor investigation means for investigating clutter factor,
By the clutter factor investigation means Only the radar echoes in the observation area are extracted, and the radar echoes in the observation area in a situation where no pre-stored clutter occurs are compared with the extracted radar echoes in the observation area. Clutter level determining means for determining the level;
Outputs information indicating the reliability of the target detection result based on the clutter level determined by the clutter level determination means. When the clutter level becomes high, a warning is displayed. A target detection system comprising: a reliability information output unit.
[0017]
Information indicating reliability output by the reliability information output means Is a composite image of the map image of the observation area and the target symbol. It is more preferable to further include a display means for visual display and to perform visual display.
[0018]
Here, it is preferable that the system further includes a threshold adjustment unit that adjusts the threshold according to a determination result of the clutter level determination unit.
[0019]
Alternatively, the clutter factor investigation means is means for obtaining a signal value representing a radar echo of a pseudo target installed in the radar coverage, and the clutter level determination means compares the obtained signal value with a predetermined signal value. By doing so, it may be a means for determining the level of clutter that may occur.
[0020]
Alternatively, the clutter factor investigating means is a means for calculating the attenuation amount of the radar echo of the pseudo target installed in the radar coverage, and the clutter level determining means is based on the attenuation amount. It may be a means for determining the level.
[0021]
Alternatively, the clutter factor investigation means is a rainfall intensity meter installed at a predetermined observation point in the radar coverage, and the clutter level determination means is a clutter level that can be generated based on a measurement value of the rainfall intensity meter. It may be a means for determining the level.
[0022]
Alternatively, the clutter factor investigation means is a means comprising a voice receiving device that acquires weather information provided as voice and a voice recognition device that converts the acquired weather information into numerical data, and the clutter level determination means includes: Means for determining the level of clutter that may occur based on the numerical data may be used.
[0023]
Alternatively, the clutter factor investigation means is a pattern recognition processing device that converts weather information provided as an image into numerical data, and the clutter level determination means determines the level of clutter that can occur based on the numerical data. It may be a means for determining. In this case, as the weather information provided as the image, the weather information distributed by the Internet, the weather information distributed by television teletext, the weather information acquired by the weather satellite, the weather information acquired by the weather radar Weather information can be considered.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described. Note that each of the following embodiments is a system that receives the radar video 11 that is the output of the ASDE 101 in FIG.
[0025]
Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating a configuration of the target detection system according to the first embodiment. As shown in the figure, this system includes an A / D converter 34 that converts an input radar video 11 into a digital signal, a radar timing converter 36 that generates a transmission / reception timing signal of the radar, and a generated timing. A range / azimuth integration processing unit 39 (range: distance direction, azimuth: azimuth direction) for integrating the radar video 38 based on the signal 37, and a radar video buffer unit 41 for temporarily recording the integrated radar video 40. A threshold level calculation unit 44 for calculating a threshold level for hit test, a hit test processing unit 45 for truncating a signal below the calculated threshold level, and a radar video 47 extracted by the hit test 2 Dimension memory 48 and radar video 49 A shrinkage processing unit 50 for reducing minute clutter, a two-dimensional moving average processing unit 52 for removing noise by moving average processing the data after clutter reduction, and a blank map indicating a target detection unnecessary area such as a terminal building Blank map memory 56 to store, binarization processing unit 54 for detecting a target based on radar video 53 and blank map 57 after noise removal, and clustering / labeling processing unit for labeling and integrating the detected target 58, a center-of-gravity position calculation processing unit 60 that calculates the center-of-gravity position of the target, a target tracking processing unit 62 that tracks a target that moves based on the change in the calculated center-of-gravity position, and the position of the detected and tracked target A display data generation processing unit 64 that converts the data into a format and outputs it to the high-function display device 6.
[0026]
The system further includes a radar map memory 66 corresponding to the clutter factor investigation means of the present invention and a clutter level determination unit 68 corresponding to the clutter level determination means. The display data generation processing unit 64 also has a function as reliability information output means of the present invention.
[0027]
Next, the operation of this system, that is, the processing performed by each of the above means will be described. The radar video 11 that is the output of ASDE is input to the A / D converter 34 and converted into a digital signal (radar video 38). On the other hand, an ACP (Azimuth Count Pulse), an ARP (Azimuth Reference Pulse), and a trigger signal 35 from a radar are input to a radar timing conversion unit 36 and a range / azimuth integration processing unit as an internal timing signal 37 for radar video processing. 39. The range / azimuth integration processing unit 39 grasps the radar antenna rotation timing and the measurement unit in the distance direction from the internal timing signal 37, and integrates the radar video 38 in accordance with them. When sweeping is repeated at the same place, a high signal value is always obtained if the radar echo is actually strong, and therefore a high value can be obtained even if integration processing is performed. On the other hand, for example, electrical noise and the like are generated randomly, so that a low value is obtained if integration is performed. That is, only the radar echo signal is enhanced by the range / azimuth integration process. After the integration process, the radar video 40 is stored in the radar video buffer unit 41 for several sweeps, and is sequentially output to the threshold level calculation unit 44 and the hit test processing unit 45 for each sweep. The threshold level calculation unit 44 calculates a threshold level for a hit test process to be described later for each sweep. The threshold level is calculated based on the information 69 sent from the clutter level determination unit 68. This process will be described later. Also, the threshold level can be calculated based on the information 103 manually input by the controller. Which information the threshold level calculation unit 44 refers to is switched by the automatic / manual switch 102.
[0028]
The target detection is performed by the binarization processing unit 54 after three-stage preprocessing by the hit test processing unit 45, the contraction processing unit 50, and the two-dimensional moving average processing unit 52. First, the hit test processing unit 45 compares the calculated threshold level 46 with the radar video 43 for each sweep, and if the amplitude of the signal exceeds the threshold level 46, it is regarded as a hit, and the signal that has not been hit is discarded. As a result, the radar video 47 for each sweep in which the amplitude of signals other than the hit signal is 0 is sequentially recorded in the two-dimensional memory 48. With this processing, a part of noise included in the radar video 43 can be removed. Here, once the radar video 47 is recorded in the two-dimensional memory 48, the radar video that has been processed for each sweep (one-dimensionally) is converted into a range (distance direction), azimuth (azimuth) in the subsequent processing. (Direction) can be handled as a two-dimensional image having coordinate axes. Next, the contraction processing unit 50 performs image processing on the radar video 49 that has become a two-dimensional image, and removes scattered clutter as unnecessary signals. This is because a target such as an airplane has a certain size, and thus signals appearing scatteredly may be regarded as minute clutter. Next, the two-dimensional moving average processing unit 52 performs two-dimensional moving average processing on the radar video 51 after removing the fine clutter. In the two-dimensional moving average processing, the two-dimensional image is smoothed as a whole by replacing the signal value of each pixel constituting the two-dimensional image with an average value obtained by applying a predetermined weight to the values of the surrounding pixels. It is processing. By this processing, noise mixed in an effective signal can be removed. The binarization processing unit 54 binarizes the radar video 53 that has undergone the above preprocessing based on a predetermined threshold level. However, since the position of a building such as a terminal building does not need to be detected again, when performing binarization processing, the blank map 57 storing the target detection unnecessary area is read from the blank map memory 56 and the target detection is not required. The signal value of the area is 0, and binarization is performed for the other areas. Thereby, the binarized image 55 in which only the signal indicating the detection target remains is obtained.
[0029]
Next, the clustering / labeling processing unit 58 integrates the signals in the radar video 55 for each group (cluster), and labels each cluster. That is, a label is attached to each target such as an airplane or a vehicle. The center-of-gravity position calculation processing unit 60 calculates the center-of-gravity position of each target based on the binarized image 59 labeled. The target tracking processing unit 62 temporarily stores the calculated data 61 of the center of gravity position, generates tracking data 63 representing the difference from the data stored before one scan, and receives the received data by the display data generation processing unit 64. hand over. Based on these data, the display data generation processing unit 64 synthesizes a map image showing airport facilities and a symbol showing an airplane or the like. Furthermore, display data 65 in a predetermined format is generated and output to the high function display device 6 by performing an enlargement process on the surrounding map image where the target is detected as necessary.
[0030]
Next, processing of the radar map memory 66 and the clutter level determination unit 68 that should be called the features of the present invention will be described. The processing performed by the display data generation processing unit 64 described above as reliability information output means of the present invention will also be described. The radar map memory 66 stores a predetermined observation area of the radar coverage, and when an ACP, ARP, or trigger signal 35 is input from the radar, it is distinguished whether the area being swept is an observation area. be able to. The clutter level determination unit 68 receives the map coordinates 67 of the observation area from the radar map memory 66 and collates it with the radar video 38 after digital conversion received from the A / D conversion unit 34 to thereby detect the radar of the observation area. Extract only echo. At this time, the clutter level determination unit 68 stores in advance radar echoes in the observation area in a situation where no clutter occurs, such as during fine weather. The clutter level determination unit 68 compares the radar echoes in the observation area with the radar echoes stored in advance, determines how much clutter is occurring, and determines the level according to the degree of occurrence. The determination information is input to the display data generation processing unit 64 and the threshold level calculation unit 44 described above.
[0031]
Based on the determination information 70 from the clutter level determination unit 68, the display data generation processing unit 64 combines characters, marks, and the like indicating detection accuracy or system reliability with the image indicating the target position described above. Output to the high function display device 6. FIG. 2 is a diagram illustrating an example of a display screen. In the upper right part of the display screen, a display 99 indicating that the reliability of target detection is C rank is displayed. Depending on the clutter level, this display changes like “Reliability A” and “Reliability B”. In the first embodiment, the reliability display is always performed. However, the warning message may be displayed only when the clutter level becomes high, that is, when the reliability decreases. The controller will be alerted to visual control based on the reliability indication of the target detection. For example, when the weather is fine, the clutter level is low, and the reliability of target detection is displayed as “Reliability A”. In such a case, the display reliability of the present system is high, and visual control can be limited to a confirmation level. On the contrary, the clutter level becomes high during rainy weather, and the reliability of target detection is displayed as “Reliability C”. In such a case, the reliability of the display by this system becomes low, and it is necessary to carefully perform visual control. As described above, by displaying the reliability of target detection on the screen and presenting it to the controller, the controller can efficiently use the information from this system and perform visual control.
[0032]
On the other hand, the threshold level calculation unit 44 sets the threshold level to a predetermined fixed value when the clutter level is low, and sets a threshold level higher than normal when the clutter level is high, based on the determination information 69, for example. Automatically adjust the threshold level for the test. Alternatively, the threshold level may be set based on the information 103 input by the controller using the system by switching the input to the threshold level calculation unit 44 by the automatic / manual switch 102. In other words, the controller may visually confirm the display of the reliability of the target detection on the display screen of the high-function display device 6 and manually adjust the threshold level to be optimum based on an independent determination.
[0033]
3 and 4 are diagrams for explaining the effectiveness of the reliability display and the adjustment of the threshold level. FIG. 3 is a radar video display of an aircraft 92 and a surrounding buffered green area 91. FIG. 3 (a) shows the time when the weather is fine, and FIG. 3 (b) shows the time when it rains. As shown in FIG. 3B, during the rain, the radar echo from the airport surface itself becomes large due to the rain, so the obtained image is the radar echo from the aircraft 92 and the buffered green space 91. The image is buried in 94. FIG. 4 is a diagram showing the amplitude of the radar echo. 4A shows the amplitude in the cross section X in FIG. 3A, and FIG. 4B shows the amplitude in the cross section Y in FIG. 3B. As is clear from these figures, in clear weather, the radar echo 95 of the aircraft is larger than the radar echo 96 of the buffer green space, and the aircraft target can be easily recognized. The radar echo amplitude in the observation area 93 is also smaller than that of the aircraft echo 95. On the other hand, it is difficult to compare the radar echo 96 of the buffer green space 91 with the radar echo 95 of the aircraft during rain.
[0034]
Therefore, as described above, determining the clutter level based on radar echoes in the observation area, evaluating the reliability of the system based on this, and notifying the user reduce the load on the air traffic controller, It can be said that it is effective in improving the control efficiency and ensuring safety. Furthermore, if the threshold level for hit verification is adjusted based on the clutter level of the observation area, the system performance can be drawn to the limit and a warning can be issued only when there is still a problem in detection accuracy.
[0035]
Embodiment 2.
Figure 5 These are block diagrams which show the structure of the target detection system of Embodiment 2. FIG. In the first embodiment, in order to investigate how much clutter causes the airport surface, an observation area is provided and radar echoes in the area are extracted from the radar video. A pseudo target is set in the area, and a radar echo of the pseudo target is acquired. For this purpose, the system of the second embodiment includes a pseudo target processing unit 85 in place of the radar map memory of the first embodiment, and further includes other means similar to those of the first embodiment.
[0036]
Next, processing of the system according to the second embodiment will be described. In the system according to the second embodiment, as shown in FIG. 6A, it is necessary that the pseudo target 97 is installed around the airport and the vicinity of the airport. The radar echo of the pseudo target 97 in fine weather is observed in advance and stored in the clutter level determination unit 68. The pseudo target processing unit 85 converts the ratio between the stored radar echo and the radar echo 98 of the pseudo target acquired at the time of target search as shown in FIG. 86 is passed to the clutter level determination unit 68. The clutter level determination unit 68 determines the clutter level based on the clutter observation reference data 86. The processing of each other means is the same as the processing of each means described in the first embodiment.
[0037]
As in the first embodiment, the second embodiment is effective in reducing the load on the air traffic controller, improving the control efficiency, and ensuring safety. Since it is possible to determine the ratio of the radar echo when it is sunny and when it rains more accurately than when observing the area, the accuracy of the clutter level determination is improved compared to the first embodiment.
[0038]
Embodiment 3.
FIG. 7 is a block diagram illustrating a configuration of the target detection system according to the third embodiment. This system is a system for measuring radar echoes of a pseudo target installed in a radar coverage area as in the second embodiment, and includes a radar echo attenuation determination unit 87 instead of the pseudo target processing unit 85 in the second embodiment. . Since radio waves with short wavelengths are significantly attenuated by rain, the clutter level is determined from the amount of radio wave attenuation.
[0039]
Next, processing of the system according to the third embodiment will be described. The radar echo attenuation determination unit 87 according to the third embodiment outputs the attenuation amount, that is, the difference to the clutter level determination unit 68 instead of the radar echo ratio. That is, the radar echo attenuation determination unit 87 stores the radar echo at the time of fine weather of the pseudo target as shown in FIG. 8A, and at the time of observation (in rainy weather) as shown in FIG. 8B. It is calculated how much the radar echo of the simulated target is attenuated as compared with that in fine weather, and the clutter level is determined based on the attenuation amount 88. The processing of each other means is the same as the processing of each means described in the first embodiment.
[0040]
The third embodiment, like the first and second embodiments, is effective in reducing the load of the air traffic controller, improving the control efficiency and ensuring safety, and by setting a pseudo target, Accurate determination can be made.
[0041]
Embodiment 4 FIG.
FIG. 9 is a block diagram illustrating a configuration of the target detection system according to the fourth embodiment. The fourth embodiment includes a rainfall intensity meter 71 as means for examining clutter factors, and also includes the same means as in the first embodiment.
[0042]
The clutter level determination unit 68 determines the clutter level based on the rainfall intensity 72 measured by the rainfall intensity meter 71. The processing of each other means is the same as the processing of each means described in the first embodiment.
[0043]
The fourth embodiment is effective in reducing the load on the air traffic controller and improving the control efficiency to ensure safety, as in the above-described embodiments. In addition, since the radar echo is not used for the clutter level determination and the measurement value of the rainfall intensity meter 71 is used, the trigger signal 35 or the radar video 38 from the radar ACP or the like is not required to investigate the clutter factor. For this reason, the system can be simplified.
[0044]
Embodiment 5.
FIG. 10 is a block diagram illustrating a configuration of the target detection system according to the fifth embodiment. In the fifth embodiment, airport information that is periodically updated is used in order to investigate clutter factors. As a means for that purpose, an airport information receiving device 73 and a voice recognition device 75 are provided. Means similar to those of the first embodiment are provided.
[0045]
The airport information receiving device 73 receives radio waves from an airport information transmitting device (ATIS) that is constantly performing audio broadcasting related to the wind direction, wind speed, and weather around the airport. Since the received airport information is voice information, the voice recognition device 75 converts it to numerical data. The clutter level determination unit 68 extracts only information related to rainfall from the digitized airport information 76, and determines the clutter level based on this information. The processing of each other means is the same as the processing of each means described in the first embodiment.
[0046]
The fifth embodiment is effective in reducing the load on the air traffic controller and improving the control efficiency to ensure safety, as in the above-described embodiments. In addition, unlike the above-described embodiments, it is not necessary to newly install equipment in the radar coverage area, and an existing airport information receiving device or voice recognition device may be used. Can do.
[0047]
Embodiment 6.
FIG. 11 is a block diagram illustrating a configuration of the target detection system according to the sixth embodiment. In the sixth embodiment, weather information provided on the Internet is used to investigate clutter factors. As a means for this, an Internet connection terminal 77 and a pattern recognition device 79 are provided. 1 is provided. The Internet connection terminal 77 is an information processing terminal provided with communication facilities such as a router, a terminal adapter, and a modem.
[0048]
The Internet connection terminal 77 is always or periodically connected to the Internet, and acquires weather information around the radar coverage from a Web site that provides weather information. The pattern recognition device 79 processes weather information 78 provided as characters or images based on a known pattern recognition method, and converts it into numerical data. The clutter level determination unit 68 extracts only information related to rainfall from the digitized weather information 80, and determines the clutter level based on this information. The processing of each other means is the same as the processing of each means described in the first embodiment.
[0049]
The sixth embodiment is effective in reducing the load on the air traffic controller, improving the control efficiency, and ensuring safety, as in the previous embodiments. Further, as in the fifth embodiment, it is not necessary to newly install equipment in the radar coverage area, and an existing Internet connection terminal or pattern recognition device may be used, so that a system can be constructed at low cost.
[0050]
Embodiment 7 FIG.
FIG. 12 is a block diagram illustrating a configuration of the target detection system according to the seventh embodiment. The seventh embodiment is a form in which television teletext is used to investigate clutter factors, and includes a teletext broadcast receiving terminal 83 and a pattern recognition device 79 as means for that purpose. Similar means are provided.
[0051]
The television teletext terminal 83 receives broadcast radio waves related to weather information among text broadcasts. The pattern recognition device 79 processes the weather information 84 of the character based on a known pattern recognition method, and converts it into numerical data. The clutter level determination unit 68 extracts only information related to rainfall from the digitized weather information 80, and determines the clutter level based on this information. The processing of each other means is the same as the processing of each means described in the first embodiment.
[0052]
The seventh embodiment is effective in reducing the load on the air traffic controller, improving the control efficiency, and ensuring safety, as in the previous embodiments. In addition, there is an advantage that pattern recognition is easy in that the received information is limited to characters.
[0053]
Embodiment 8 FIG.
FIG. 13 is a block diagram illustrating a configuration of the target detection system according to the eighth embodiment. In the eighth embodiment, meteorological satellite data (for example, a ground observation photograph of a meteorological satellite sunflower) is used in order to investigate clutter factors. As means for this, a meteorological satellite data receiving terminal 81, a pattern recognition device 79, and the like are used. And other means similar to those of the first embodiment. The meteorological satellite data receiving terminal 81 may be a terminal that installs a satellite antenna for receiving radio waves from the weather satellite sunflower in the airport and receives a signal from the antenna, but from a specialized organization equipped with an antenna and receiving equipment. It may be a terminal that receives data through a telephone line or the like.
[0054]
FIG. 14 is an example of a ground photograph taken by the weather satellite Himawari, and shows a state where the cloud 100 covers the entire Japanese archipelago. Such image information 82 received by the meteorological satellite data receiving terminal 81 is processed by the pattern recognition device 79. For example, based on a known pattern recognition method, the movement and occurrence of the cloud 100 are roughly recognized, and the rainfall intensity in the radar coverage is estimated from the situation, and the rainfall intensity is converted into numerical data. The clutter level determination unit 68 determines the clutter level based on the numerical data 80. The processing of each other means is the same as the processing of each means described in the first embodiment.
[0055]
The eighth embodiment is effective in reducing the load on the air traffic controller, improving the control efficiency, and ensuring safety, as in the previous embodiments.
[0056]
Embodiment 9 FIG.
FIG. 15 is a block diagram illustrating a configuration of the target detection system according to the ninth embodiment. In the ninth embodiment, a weather radar is used to investigate clutter factors. As a means for that purpose, a weather radar receiving terminal 89 and a pattern recognition device 79 are provided. Means.
[0057]
In this system, weather radar rainfall information 90 is received by an airport weather radar receiving terminal 89 installed around the airport. Further, the pattern recognition device 79 recognizes the cloud generation state and predicts rainfall. The rainfall prediction result is converted into numerical data 80, and the clutter level determination unit 68 performs clutter determination.
[0058]
The ninth embodiment is effective in reducing the load on the air traffic controller and improving the control efficiency to ensure safety, as in the above-described embodiments. In addition, by replacing the image data from the meteorological satellite according to the eighth embodiment with the received data from the weather radar, it is possible to detect the movement of the cloud in real time and to determine the clutter level more accurately. .
[0059]
Other embodiments.
In each of the above embodiments, a character indicating the reliability of target detection is output on the display screen. However, a warning mark may be displayed instead of the character, a beep sound or sound A warning by sound such as a message may be issued.
[0060]
In each of the above-described embodiments, target detection is performed by performing binarization processing after three stages of hit verification, contraction processing, and two-dimensional moving average processing, and hit verification processing among them. Although the threshold level used in is adjusted based on the clutter level determination result, the threshold level to be adjusted is not limited to that for hit testing. For example, the threshold level used in the binarization process is adjusted. May be. In addition to the above, various methods for detecting a target by defining a threshold level are conceivable, but the method of the present invention is applicable to any case. In addition, in the case of a method of defining a plurality of threshold levels and performing target detection step by step, the determination result of the clutter level may be used at any step.
[0061]
【The invention's effect】
Target detection system of the present invention Mu According to the survey, the clutter factors such as rainfall are investigated, and the reliability of target detection is evaluated and displayed using the survey results. Can be appropriately warned to a user such as an air traffic controller. As a result, efficient target detection can be realized without imposing an excessive burden on the user, accidents due to overconfidence of the system can be prevented, and traffic safety can be achieved.
[0062]
In addition, if the threshold for target detection is adjusted according to the survey results, reliability is reduced only when there is a risk of erroneous target detection while maximizing system performance. A warning to this effect can be issued.
[0063]
At this time, if the cause of clutter is investigated by extracting the radar echo from a predetermined observation area and comparing it with the radar echo stored in advance, it is possible to determine exactly how much clutter can actually occur. I can grasp it. In addition, a pseudo target is set up, and the radar echo is compared with a pre-stored radar echo, or the attenuation of the radar echo from the pseudo target is calculated, and the cause of clutter is investigated based on it. In this case, a more accurate judgment can be made.
[0064]
In addition, if a rainfall intensity meter is installed in the radar coverage and the cause of clutter is investigated based on the measured rainfall intensity, it is not necessary to extract radar echo for clutter level determination, thus simplifying the system be able to.
[0065]
In addition, if information on rainfall and snowfall that is a cause of clutter is extracted from airport information that is periodically transmitted and the clutter level is determined based on that information, it is necessary to install new equipment in the radar coverage area. In addition, since an existing airport information receiver can be used, a system can be constructed at a low cost.
[0066]
In addition, by performing well-known pattern recognition processing on weather information obtained from the Internet and TV teletext, satellite images distributed from weather satellites, and images acquired by weather radar, It is not necessary to install new equipment in the radar coverage area and to build a low-cost system using existing equipment when taking out snowfall information and determining the clutter level based on that information. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a system configuration in Embodiment 1 of the present invention.
FIG. 2 is a diagram showing an example of a target detection result display screen in the first embodiment.
FIG. 3 is a diagram for explaining the effect of the first embodiment;
FIG. 4 is a diagram for explaining the effect of the first embodiment.
FIG. 5 is a block diagram showing a system configuration according to Embodiment 2 of the present invention.
6 is a diagram for explaining a target detection method in Embodiment 2. FIG.
FIG. 7 is a block diagram showing a system configuration according to Embodiment 3 of the present invention.
8 is a diagram for explaining a target detection method according to Embodiment 3. FIG.
FIG. 9 is a block diagram showing a system configuration in Embodiment 4 of the present invention.
FIG. 10 is a block diagram showing a system configuration in a fifth embodiment of the present invention.
FIG. 11 is a block diagram showing a system configuration according to Embodiment 6 of the present invention.
FIG. 12 is a block diagram showing a system configuration according to Embodiment 7 of the present invention.
FIG. 13 is a block diagram showing a system configuration in an eighth embodiment of the present invention.
FIG. 14 is a diagram showing an example of a satellite photograph acquired by the meteorological satellite data receiving terminal according to the eighth embodiment.
FIG. 15 is a block diagram showing a system configuration according to Embodiment 9 of the present invention.
FIG. 16 is a block diagram showing an example of a conventional target detection system.
[Explanation of symbols]
7 radio waves, 9 received radio waves, 10 transmit radio waves, 11, 16 radar video, 12 ADSE target detection position data, 13 aircraft identification display data, 17 target detection data, 19 flight plan data, 22 image data, 23 blind target position data, 26 SSR mode S signal, 27 SSR mode S position data, 30 GPS position data, 31 vehicle position information, 33 collision prediction data, 35 ACP, ARP, trigger signal, 37 timing signal, 38, 40, 43, 47, 49, 51, 53 Radar video, 46 Threshold level, 55, 59 Binary image, 57 Blank map, 61 Center of gravity position data, 63 Tracking data, 64 Display data generation processing unit (reliability information output means), 65 Display data , 66 Radar map memory (clutter factor investigation means), 67 map coordinates, 68 Clutter level determination unit, 69, 70 Judgment information, 72 Rainfall intensity, 76 Airport information, 78, 80, 84 Weather information, 82 Image information, 86 Clutter observation reference data, 88 Attenuation, 90 Rainfall information, 91 Buffer green space, 92 Aircraft, 93 Observation area , 94 Radar echo due to rain, 95 Radar echo of aircraft, 96 Radar echo of buffer green space, 97 Pseudo target, 98 Pseudo target radar echo, 99 Reliability display, 100 clouds, 101 ASDE, 102 Automatic / manual switcher, 103 Information entered by the controller.

Claims (13)

In a target detection system that detects a target based on whether or not a signal value representing radar echo exceeds a predetermined threshold, and displays the position of the target on a display screen,
A predetermined observation area of the radar coverage is stored, and a clutter factor investigation means for investigating the clutter factor by distinguishing whether the area being swept is an observation area or not by an input signal from the radar ,
Extract only the radar echo of the observation area by the clutter factor investigation means , compare the radar echo of the observation area in the situation where the pre-stored clutter does not occur and the radar echo of the extracted observation area, Clutter level determination means for determining the level according to
Reliability information output means for outputting information indicating the reliability of the target detection result based on the clutter level determined by the clutter level determination means and displaying a warning when the clutter level becomes high. A target detection system characterized by that. A / D conversion means for digitizing an analog signal representing radar echo,
Recording means for temporarily recording a radar echo signal digitized by the A / D conversion means;
A target extraction means for comparing the value of the signal recorded in the recording means with a predetermined threshold to determine a signal that exceeds the threshold as a signal representing a target, and for extracting a target;
A predetermined observation area of the radar coverage is stored, and a clutter factor investigation means for investigating the clutter factor by distinguishing whether the area being swept is an observation area or not by an input signal from the radar ,
Extract only the radar echo of the observation area by the clutter factor investigation means , compare the radar echo of the observation area in the situation where the pre-stored clutter does not occur and the radar echo of the extracted observation area, Clutter level determination means for determining the level according to
Reliability information output means for outputting information indicating the reliability of the target detection result based on the clutter level determined by the clutter level determination means and displaying a warning when the clutter level becomes high. A target detection system characterized by that. The information indicating the reliability output by the reliability information output means further comprises display means for visually displaying a map image of the observation area and a target symbol on a screen obtained by image synthesis. Or the target detection system of 2 description. 4. The target detection system according to claim 1, further comprising a threshold adjustment unit that adjusts the threshold according to a determination result of the clutter level determination unit. The clutter factor investigation means is means for obtaining a signal value representing a radar echo of a pseudo target installed in the radar coverage area,
The said clutter level determination means is a means to determine the level of the clutter which can generate | occur | produce by comparing the acquired signal value with a predetermined | prescribed signal value, The Claim 1 characterized by the above-mentioned. Target detection system. The clutter factor investigation means is means for calculating the attenuation amount of the radar echo of the pseudo target installed in the radar coverage area,
5. The target detection system according to claim 1, wherein the clutter level determination unit is a unit that determines a level of a clutter that can be generated based on the amount of attenuation. The clutter factor investigation means is a rainfall intensity meter installed at a predetermined observation point in the radar coverage area,
5. The target detection system according to claim 1, wherein the clutter level determination unit is a unit that determines a level of a clutter that may occur based on a measurement value of the rainfall intensity meter. The clutter factor investigation means includes a voice receiving device that acquires weather information provided as voice, and a voice recognition device that converts the acquired weather information into numerical data.
5. The target detection system according to claim 1, wherein the clutter level determination unit is a unit that determines a level of a clutter that can be generated based on the numerical data. The clutter factor investigation means is a pattern recognition processing device that converts weather information provided as an image into numerical data,
5. The target detection system according to claim 1, wherein the clutter level determination unit is a unit that determines a level of a clutter that can be generated based on the numerical data. The target detection system according to claim 9, wherein the weather information provided as the image is weather information distributed via the Internet. The target detection system according to claim 9, wherein the information provided as the image is weather information distributed by teletext on a television. The target detection system according to claim 9, wherein the weather information provided as the image is weather information acquired and distributed by a weather satellite. The target detection system according to claim 9, wherein the information provided as the image is weather information acquired by a weather radar.

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