JPH09230040A - Tracking data judging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To select correct information and collate it with tracking even when information generated from a moving body is seemingly input as a plurality of information, for the purpose of performing automatic collation of tracking of radar information with tracking data, and automatic collation of the tracking data with information of the attribute of the moving body, by setting a code generated from the moving body as an identifier in radar information processing. SOLUTION: Correct tracking data 13 of a radar are selected in a plurality of radar tracking data of a moving body from the previously obtained course information of the moving body 4 and the generated position of the moving body 4 obtained from the radar 1. An average value is computed from coordinates of a plurality of radar targets 11 so as to synthesize them into a single radar target 11. Further, when a reliability facter is not higher than a previously set reference value, the tracking is interrupted, and the tracking data 13 are removed from a display screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving object monitoring system such as an air traffic control system using a radar, which automatically tracks radar information and collates it with tracking data, and tracks tracking data and attribute information of a moving object such as an aircraft. The present invention relates to the performance improvement of a radar control information processing system that facilitates automatic verification of.

[0002]

2. Description of the Related Art Generally, a primary surveillance radar called PSR can confirm the existence of the aircraft by receiving a reflected wave from the aircraft, but a secondary surveillance radar called SSR is It is possible to transmit an inquiry wave to an aircraft and identify the aircraft by the discrete beacon code included in the response wave from the aircraft. An important problem is automatic correlation that associates the radar target obtained from the response wave with a target of an aircraft with the tracking data displayed on the display screen as the air control data.

FIG. 6 is a flowchart showing a method of selecting a radar target that can be used as tracking data in a conventional tracking process. A method of selecting a radar target that can be used as tracking data from the radar target will be described below with reference to the flowchart of FIG. The response wave input to the secondary surveillance radar is digitized by the data processing section of the secondary surveillance radar and sent to the tracking processing device as position information and radar target. The radar target is input at almost constant intervals according to the rotation cycle of the secondary surveillance radar. Since the discrete beacon code set by the pilot is not changed in principle, the tracking data created from the radar target input up to the previous time and the radar target input this time have the same discrete beacon code (step S40). ), If the difference in position between the two is within the range of the velocity of the aircraft or the measurement error of the radar and the radar target that responds to the discrete beacon code is single (step S41), it can be determined that they are the same aircraft ( Step S
42). If there are a plurality of radar targets, the judgment is stopped or one of them is selected (step S43). Further, if there is no radar target that responds with the same beacon code in step S40, naturally the correlation between the radar target and tracking data is not established (step S44).

Next, the automatic correlation between the tracking data of the radar target and the aircraft attribute information in the above conventional air traffic control will be described with reference to the flowchart of FIG. The discrete beacon code of the aircraft attribute information is assigned to only one aircraft, and the aircraft in flight responds to the discrete beacon code by one.
Since it is only the aircraft, by searching for the one that has a one-to-one correspondence with the discrete beacon code stored in the radar control information processing system with the discrete beacon code in the tracking data (step S4
5) The tracking data and the aircraft attribute information are automatically correlated (step S47). In step S46, if there is not only one tracking data that responds with the same beacon code, there is no correlation between the tracking data and the aircraft attribute information (step S).
48).

Next, a method of determining whether or not to continue tracking will be described with reference to the flowchart of FIG. The reliability coefficient with high tracking accuracy is used, and the coefficient is changed depending on the correlation with the radar target. That is, tracking data correlated with the radar target (step S49) raises the reliability coefficient of tracking (step S50), and tracking data not correlated with the radar target lowers the reliability coefficient of tracking (step S51). . When the reliability coefficient of tracking falls below a certain value, the continuation of tracking is stopped (step S53). If the reliability coefficient is not equal to or less than the predetermined value in step S52, it is considered that the correlation is established, and the tracking is further continued (step S54).

[0006]

Since the conventional tracking data determination method is configured as described above, even if a single aircraft is assigned a beacon code that does not exist in the control area or radar coverage area. However, due to the lack of the central part of the radar response wave, one radar target or a plurality of radar targets may actually appear to be split. This is called a split phenomenon.
If the missing part is small, it can be determined that one target is cracked and appears as multiple targets, but if the threshold value set by the system is exceeded, there may actually be multiple aircraft,
It is determined that there are multiple radar targets. Therefore, it is not possible to determine which radar target is positive in tracking,
It was one of the causes of the deterioration of tracking quality.

Further, due to the reflection of buildings near the radar and other causes, there is a case where an aircraft having the same beacon code is input from the radar as if it were present at a position that does not actually exist. This is called a ghost. In particular, this phenomenon often occurs immediately after the aircraft takes off from the airport. Therefore, when a ghost phenomenon occurs, a plurality of tracking data having the same candidate discrete beacon code are generated in the tracking processing device, and even if an attempt is made to automatically associate aircraft information with tracking data, it is not independent. Therefore, correct tracking data could not be determined.

Further, even if the ghost phenomenon disappears after the occurrence of the ghost phenomenon, if the tracking continues for a long time until then, the tracking data is not erased in order to deal with a temporary loss of the radar target, and the above phenomenon occurs. Had the flaw that it would continue. There is also a problem in that a non-existent aircraft is displayed as if it were present.

The present invention has been made in order to solve the above-mentioned problems, and even if a ghost phenomenon or a split phenomenon occurs in the radar, the automatic control of the aircraft information and the radar target can be started as much as possible to control. The purpose is to reduce the public burden and improve the tracking performance.

[0010]

According to the tracking data determination method of the present invention, a response wave including a discrete beacon code is transmitted to a secondary monitoring radar from a moving body within a radar coverage area by emitting an interrogation wave from the secondary monitoring radar. In the mobile object monitoring system that returns, the respective altitudes of the plurality of radar targets match, the respective range coordinates are within the preset first reference value, and the distance between the respective radar targets is set to the second preset target. When it is within the reference value, the average value is calculated from the coordinates of the plurality of radar targets and combined into a single radar target.

In addition, in a mobile body monitoring system that transmits an interrogation wave from the secondary surveillance radar and returns a response wave including a discrete beacon code from the mobile body within the radar coverage area to the secondary surveillance radar, it is more appropriate than the mobile body attribute information. When the tracking data in the range determined as the position and altitude and the altitude of the tracking data other than the range determined as the appropriate position are close to each other, the tracking data outside the range determined as the appropriate position are regarded as ghosts. It is a judgment.

Further, when the tracking data is determined to be a ghost, the tracking data is erased from the display screen.

Further, when the tracking data is determined to be a ghost, the display form of the tracking data is changed.

Furthermore, in the moving body monitoring system, the interrogating wave is emitted from the secondary monitoring radar, and the response wave containing the discrete beacon code is returned from the moving body within the radar coverage area to the secondary monitoring radar. When the correlation between the radar target input to the tracking processing device and the tracking data generated by the tracking processing device is not established at regular intervals depending on the rotation cycle, the reliability coefficient is reduced by a preset ratio, When the reliability coefficient is less than or equal to a preset ghost elimination reference value, tracking data in a range determined to be an appropriate position and altitude from the mobile attribute information and altitudes of tracking data outside the range determined to be an appropriate position. Is close, tracking data other than the range determined to be an appropriate position is deleted from the display screen.

Further, a moving body monitoring in which an interrogation wave is emitted from the secondary monitoring radar and a response wave including a discrete beacon code is returned from the moving body within the radar coverage area to the secondary monitoring radar to generate tracking data by a tracking processing device. In the system, when the correlation between the radar target input to the tracking processing device and the tracking data generated by the tracking processing device is not established at regular intervals according to the rotation cycle of the secondary monitoring radar, the reliability coefficient Is reduced by a preset ratio, and when the reliability coefficient is equal to or lower than a preset reference value, the display form of the tracking data is changed and the tracking is continued.

Further, the moving body monitoring in which the secondary monitoring radar emits an interrogation wave, and a response wave including a discrete beacon code is returned from the moving body within the radar coverage area to the secondary monitoring radar to generate tracking data by the tracking processing device. In the system, when the correlation between the radar target input to the tracking processing device and the tracking data generated by the tracking processing device is not established at regular intervals according to the rotation cycle of the secondary monitoring radar, the reliability coefficient Is reduced by a preset first ratio, and when the reliability coefficient is less than or equal to a preset reference value, the reliability coefficient is reduced by a preset second ratio.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 shows an embodiment according to the present invention, in which tracking of radar information using a secondary surveillance radar and automatic correlation with tracking data, and automatic tracking data with attribute information of a moving object such as an aircraft are automatically performed. FIG. 1 is a system configuration diagram of an air traffic control system which is a mobile body monitoring system for realizing correlation. In FIG. 1, the sensor unit 2 of the secondary surveillance radar 1
Question wave 3 is emitted from the air. An aircraft 4 which is a mobile object within the radar coverage area and which is equipped with a transponder (not shown) capable of responding to this interrogation wave returns a response wave 5 to the secondary surveillance radar. The secondary surveillance radar 1 measures the distance from the time from the transmission of the interrogation wave 3 to the return of the response wave 5, obtains the azimuth from the azimuth at the time of transmission, and estimates the position. The response wave 5 includes a mode A beacon code and a mode C beacon code. The mode C beacon code is used for transmitting altitude information, and the mode A beacon code is mainly used for identifying an aircraft. Since the mode A beacon code is composed of 12-bit information, 4096 codes can be identified. Thousands of codes can be assigned even if they are not used for a specific code indicating an emergency condition or a specific code used for other purposes, and for aircraft flying simultaneously in the country,
It is possible to assign different codes individually. Hereinafter, a code that can be assigned to each aircraft will be referred to as a discrete beacon code. On the other hand, as the aircraft attribute information 6 including attributes such as flight number, model and destination of the aircraft, data is input from terminals in various places, and the flight data processor 7 that centrally manages aircraft information of domestic control agencies by data transmission. And is delivered to the required radar control information processing system 8 as aircraft information. In this information 6, the information of the discrete beacon code assigned to each aircraft is included and transmitted. The radar control information processing system 8 displays this information on the control console display device 9. The controller sees this information and wirelessly instructs the pilot of the aircraft to set the discrete beacon code.

Next, the operation of the first embodiment will be described. In FIG. 1, the sensor unit 2 of the secondary surveillance radar 1
Question wave 3 is emitted from the air. The aircraft 4, which has the transponder capable of responding to this interrogation wave in the aircraft 4 in the radar coverage area, returns the response wave 5 to the secondary surveillance radar 1. The response wave 5 includes a mode A beacon code and a mode C beacon code. The mode A beacon code is a discrete beacon code, and the response is digitized by the data processing unit 10 of the secondary surveillance radar 1 in a state of being divided by the split phenomenon, and is input to the tracking processing device 12 as a plurality of radar targets 11. It is generated and output as tracking data 13. FIG. 2 is a flowchart showing a method of determining whether or not a plurality of radar targets belong to a single aircraft. When there are radar targets 11 that respond with a plurality of discrete beacon codes within the allowable range of the predicted position of the current cycle of the tracking data 13 including the discrete beacon code as an attribute, if the mode C altitude information is the same. , It is extremely unlikely that there are a plurality of aircraft 4 that respond with the same altitude and the same discrete beacon code in the vicinity.
Can be determined. Further, when the split phenomenon occurs, the range coordinate of each radar target 11 is utilized by utilizing the property that the range coordinate indicating the distance is almost the same even if the position is different in the azimuth direction due to the split phenomenon in the polar coordinate. It is determined whether or not it is within the preset first range, and whether or not the distance between the respective targets in the azimuth direction is within the preset second range, and these conditions are all satisfied. For example, it is determined that the information of the response wave 5 of the single machine has caused the split phenomenon. From the coordinates of each radar target 11, the coordinates of one radar target 11 are calculated from the weighted average, and the position is calculated and combined to enable correlation with the tracking data 13.

In FIG. 2, first, a beacon code to be tracked is selected (step S1). Next, it is determined whether or not there is a radar target 11 that responds to the same bean code within the radar coverage that is within the tracking prediction allowable position (step S2), and if there is, only one radar target 11 is determined. If there are a plurality of radar targets 11, it is determined whether or not the altitudes of the radar targets 11 match (step S4). If they match, the radar targets 1 are matched.
It is determined whether the range coordinate of 1 is within the first reference value (step S5), and if it is within the reference value, it is determined whether the distance between the radar targets 11 is within the second reference value. However, if it is within the reference value, a weighted average value is calculated from the coordinates of the plurality of radar targets 11 and combined into one radar target 11, and the correlation between the radar target 11 and the tracking data 13 is calculated. It is established (step S6). When there is no radar target 11 in step S2, the correlation is not established (step S8). In step S3,
When only one radar target 11 is provided, the correlation is established (step S9). When all of the steps S4, S5, and S6 are denied, the correlation is not established or the correlation is established with the radar target 11 having a good condition (step S10).

Embodiment 2 FIG. 3 is a flowchart showing automatic correlation between tracking data and aircraft attribute data according to the embodiment of the present invention. The aircraft attribute information 6 including the information of the discrete beacon code assigned to each aircraft is delivered to the required radar control information processing system 8 as aircraft information. Assume that the response wave 5 from the aircraft 4 is reflected to generate true tracking data 13 and ghost data. The automatic correlation between the true tracking data 13 and the aircraft attribute information 6 when the ghost tracking data 13 exists will be described below with reference to the flowchart of FIG. The discrete beacon code of the aircraft attribute information 6 is assigned to only one aircraft 4. The aircraft attribute information 6 also includes route information of the aircraft 4. Therefore, it is possible to limit the range in which the tracking data 13 of the aircraft is generated within the radar coverage area. In the case of ghost tracking data, it is normal to deviate from this range, so if there is only one tracking data 13 within the generation allowable area of the tracking data 13, the tracking data 13 that responds with the discrete beacon code at another position It is possible to identify even if it exists. Further, although the altitude information can be obtained from the mode C beacon code, for example, in the case of an aircraft immediately after takeoff, the altitude should be low, which is a factor for determining that the tracking data is correct.

In FIG. 3, first, the aircraft attribute information 6 is selected (step S17). Next, it is determined whether the aircraft information 6 has been correlated with the tracking data 13 (step S18), and if it is not correlated, it is determined whether the aircraft attribute information 6 has a discrete beacon code (step S1).
9). If so, it is searched whether or not there is tracking data 13 that responds with the same discrete beacon code as the discrete beacon code (step S20). Tracking data 13 that responds with the same discrete beacon code
If there is one, it is determined whether or not there is only one tracking data 13 (step S21). If there are multiple, the tracking data 13 is generated at an appropriate position in light of the route information obtained from the aircraft attribute information 6. It is checked whether or not there is tracking data 13 (step S22). If there is one, it is further checked whether or not there is only one tracking data 13 occurring at the appropriate position (step S23). If there is only one, it is determined whether the altitude of the tracking data 13 is appropriate in light of the track information. Yes (step S24). If appropriate, it is checked whether or not the altitudes of the tracking data 13 other than the appropriate position and the tracking data 13 at the appropriate position are close to each other (step S25). If the altitudes are close to each other, the tracking data at the appropriate position is checked. 13 and the aircraft attribute information 6 are correlated with each other, and the tracking data 13 other than the appropriate position is determined to be a ghost (step S2).
6). In step S25, a plurality of tracking data 13
If the altitudes of are not close to each other, it is assumed that the tracking data 13 at the appropriate position and the aircraft attribute information 6 have a correlation,
The tracking data 13 other than the appropriate position is determined to be other than the ghost (step S29). Further, when there is only one tracking data 13 in step S21, it is assumed that the tracking data 13 and the aircraft attribute information 6 have a correlation (step S27). Furthermore, steps S22 and S
If the result in S23 or S24 is NO, the aircraft attribute information 6 and the tracking data 13 are not correlated (step S28). When it is determined to be a ghost in step S26, the tracking data 13 can be deleted from the display screen of the control console display device 9 to eliminate the ghost and monitor only the correct tracking data. Further, a method of changing the display form of the tracking data 13 such as changing the display color or blinking on the display screen of the control console display device 9 can be considered. By changing the display form, the correct tracking data can be easily viewed, and the subsequent trend of the tracking data 13 determined as a ghost can be monitored.

Embodiment 3 FIG. FIG. 4 is a flowchart showing a method of determining whether or not to continue tracking according to an embodiment of the present invention. First, the tracking data 13 as a tracking target is selected (step S31). Next, the tracking data 13
Determines whether the correlation with the radar target 11 is established (step S32), and if not established, reduces the reliability coefficient of the tracking data 13 by a preset ratio (step S33). Next, it is determined whether the reliability coefficient after the reduction is equal to or less than a preset ghost elimination reference value (step S3
4) If it is less than the reference value, the tracking data determination method described in the second embodiment is used for determination (step S35). If it is determined to be a ghost, the tracking is interrupted and the tracking data 13 is displayed on the control console. It is deleted from the display screen of the device 9 (step S37). If it is not determined to be a ghost in step S35, it is determined whether the reliability coefficient is equal to or less than the general erasure standard (step S36). If the reliability coefficient is less than the standard value, tracking is interrupted and the tracking data 13 is displayed on the control console display device 9. Is deleted from the display screen (step S37), but if it is not less than the reference value, the tracking is continued (step S39). If the correlation is established in step S32, the tracking data 13
The reliability coefficient is increased by a preset ratio and tracking is continued (step S38). In this way, since the correlation is established or not established repeatedly by continuously performing the tracking, the reliability coefficient increases or decreases, and when the reliability coefficient becomes zero, the tracking is interrupted and the tracking data 13 Is deleted from the display screen of the control console display device 9. By adopting the above determination method, even if the reliability coefficient is not lower than the general erasure standard, by determining whether or not it is a ghost, it is possible to interrupt the tracking at an early stage when it is determined to be a ghost.

Further, in step S36 of FIG. 4, even when the reliability coefficient after the reduction is equal to or less than the preset general erasure reference value, the tracking data 13 is displayed on the display screen of the control console display device 9 without interrupting the tracking. A method of changing the display form such as changing the display color or blinking can be considered, and if the reception state of the radio wave is bad due to the weather condition or the like, it is possible to continue tracking and observe the condition.

Embodiment 4 FIG. 5 is a flowchart showing a method of determining whether or not to continue tracking according to the embodiment of the present invention. First, the tracking data 13 as a tracking target
Is selected (step S48). Next, it is determined whether the tracking data 13 has a correlation with the radar target 11 (step S49). If the correlation has not been established, the tracking data 13 is determined.
The reliability coefficient is reduced by a general ratio that is a preset first ratio (step S50). Next, it is determined whether the tracking data is determined to be a ghost (step S51). When it is determined to be a ghost, the reliability coefficient of the tracking data 13 is further reduced by the ghost ratio which is a second ratio higher than the preset general ratio (step S52). Next, it is determined whether or not the reliability coefficient that has been further reduced is equal to or less than the erasing reference value (step S53). If it is less than or equal to the erasing reference value, the tracking is interrupted and the tracking data 13 is displayed on the display screen of the control console display device 9. Erase (step S5
4). When the correlation is established in step S49, the reliability coefficient of the tracking data 13 is increased by a preset ratio and the tracking is continued (step S55). Step S5
When the determination results are negative in 1 and S53, the tracking is continued (step S56).

When the tracking data and the radar target cannot be correlated with each other as described above, the reliability coefficient of the tracking data is lowered, but at this time, a different ratio is set between the tracking data which is likely to be a ghost and other tracking data. By providing and reducing the reliability coefficient, it is possible to quickly erase the tracking data, which is originally a ghost.

Although the embodiments described above have been described by taking the air traffic control system using the secondary surveillance radar as an example, it is similarly applicable to the case of monitoring a marine vessel using the secondary surveillance radar. Needless to say. Further, although the above-mentioned embodiment shows the case of the identification using the mode A beacon code of the secondary surveillance radar, the SSR mode S radar is used and the data input of a plurality of the same mode S addresses using the mode S address as an identifier. It can also be applied if there is.

[0027]

Since the present invention is configured as described above, it has the following effects.

Since an average value is calculated from the coordinates of a plurality of radar targets and combined into a single radar target,
Even if one radar target can be regarded as a plurality of aircrafts due to the split phenomenon, they are processed as a single aircraft, and the tracking performance is improved.

Further, since the tracking data other than the range determined to be an appropriate position obtained from the aircraft attribute information is determined to be a ghost, the response data of the radar may be reflected to a position different from the actual position. With respect to a ghost phenomenon in which radar information is input as if an aircraft were present, there is an effect that it can be determined as false tracking data and true tracking data can be determined.

Further, since the tracking data determined to be a ghost is erased from the display screen, only the true tracking data can be monitored without being disturbed by the ghost.

Further, since the display form of the tracking data determined to be a ghost is changed and displayed on the screen, the true tracking data can be monitored separately from the ghost, and the ghost itself can be monitored. can do.

Furthermore, if the reliability coefficient is less than or equal to a preset ghost elimination reference value, it is determined whether or not it is a ghost, and if it is determined to be a ghost, the tracking data is erased from the display screen. Since it is configured, it is possible to eliminate the ghost early.

Further, when the reliability coefficient is equal to or less than the preset reference value, the display form of the tracking data is changed and the tracking is continued. Therefore, even if there is a strong possibility that it is false tracking data, Since the situation can be monitored, there is an effect that it can contribute to safety in air traffic control.

Further, since the ratio of decreasing the reliability coefficient when the correlation is not established is changed between the normal case and the case where the ghost is likely to occur, the ghost can be erased from the display screen early. It is possible to reduce the burden on the observer.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a second embodiment of the present invention.

FIG. 3 is a flowchart showing a third embodiment of the present invention.

FIG. 4 is a flowchart showing a fourth embodiment of the present invention.

FIG. 5 is a flowchart showing a fifth embodiment of the present invention.

FIG. 6 is a flowchart showing a tracking data determination method of a conventional example.

FIG. 7 is a flowchart showing a tracking data determination method of a conventional example.

FIG. 8 is a flowchart showing a tracking data determination method of a conventional example.

[Explanation of symbols]

1 secondary surveillance radar, 3 interrogation wave, 4 moving body, 5 response wave, 6 moving body attribute information, 11 radar target, 12
Tracking processor, 13 tracking data

Claims (7)

[Claims] 1. A mobile object monitoring system that emits an interrogation wave from a secondary monitoring radar and returns a response wave including a discrete beacon code from a mobile object within a radar coverage area to the secondary monitoring radar, wherein each of a plurality of radar targets When the altitudes match and each range coordinate is within a preset first reference value and the distance between each radar target is within a preset second reference value, the coordinates of the plurality of radar targets are A tracking data determination method, characterized in that an average value is calculated from the values and combined into a single radar target. 2. In a mobile body monitoring system, which transmits an interrogation wave from a secondary surveillance radar and returns a response wave containing a discrete beacon code from a mobile body within the radar coverage area to the secondary surveillance radar, which is more appropriate than mobile body attribute information. When the tracking data in the range determined as the position and altitude and the altitude of the tracking data other than the range determined as the appropriate position are close to each other, the tracking data outside the range determined as the appropriate position are regarded as ghosts. A tracking data determination method characterized by determining. 3. The tracking data determination method according to claim 2, wherein when the tracking data is determined to be a ghost, the tracking data is erased from the display screen. 4. The tracking data determination method according to claim 2, wherein when the tracking data is determined to be a ghost, the display form of the tracking data is changed. 5. A mobile monitoring system in which an interrogation wave is emitted from a secondary surveillance radar and a response wave containing a discrete beacon code is returned from the mobile in the radar coverage area to the secondary surveillance radar. When the correlation between the radar target input to the tracking processing device and the tracking data generated by the tracking processing device is not established at regular intervals according to the cycle, the reliability coefficient is reduced by a preset ratio, and When the reliability coefficient is less than or equal to the preset ghost elimination reference value, the tracking data in a range determined to be an appropriate position and altitude from the mobile attribute information and the altitude of tracking data outside the range determined to be an appropriate position A tracking data determination method characterized in that tracking data other than a range determined to be an appropriate position is erased from the display screen when approximated. 6. A moving body monitoring system in which an interrogation wave is emitted from the secondary monitoring radar, and a response wave containing a discrete beacon code is returned from the moving body in the radar coverage area to the secondary monitoring radar to generate tracking data by a tracking processing device. In the system, when the correlation between the radar target input to the tracking processing device and the tracking data generated by the tracking processing device is not established at regular intervals according to the rotation cycle of the secondary monitoring radar, the reliability coefficient Is reduced by a preset ratio, and when the reliability coefficient is equal to or lower than a preset reference value, the display form of the tracking data is changed and the tracking is continued. 7. A moving body monitoring system in which an interrogation wave is emitted from the secondary monitoring radar, and a response wave containing a discrete beacon code is returned from the moving body within the radar coverage area to the secondary monitoring radar to generate tracking data by a tracking processing device. In the system, when the correlation between the radar target input to the tracking processing device and the tracking data generated by the tracking processing device is not established at regular intervals according to the rotation cycle of the secondary monitoring radar, the reliability coefficient Tracking data determination, characterized in that the reliability coefficient is reduced by a preset second ratio when the reliability coefficient is less than or equal to a preset reference value. Method.