JP6397665B2 - Secondary monitoring radar apparatus and azimuth correction method used for the secondary monitoring radar apparatus - Google Patents

Description

  Embodiments described herein relate generally to a secondary monitoring radar apparatus and an azimuth correction method used for the secondary monitoring radar apparatus.

  The secondary monitoring radar device receives a response signal to the interrogation signal transmitted from the ground to the aircraft, acquires various information for monitoring the target aircraft, including its position information, and outputs it as a target report. Output to. The position information is acquired as distance information and direction information from the own station based on, for example, the reception time of the response signal and the pointing direction of the antenna at that time.

  Therefore, since the accuracy of the acquired position information depends on the accuracy of the distance information as well as the accuracy of the antenna direction information, the calibration of the antenna direction is accurate with respect to the reference direction (for example, magnetic north). In addition to the adjustment, for example, based on the difference in position information for the same machine detected by the adjacent secondary monitoring radar site in operation, which has an overlapping coverage area, the difference from the reference direction is corrected more precisely. An orientation correction value is acquired, and is manually set and stored as an initial correction value in the apparatus in advance when the apparatus is installed.

JP2013-79816A (15th page, FIG. 4) Japanese Patent Laying-Open No. 2011-158452 (8th page, FIG. 2)

  By the way, with the increase in air traffic volume, the density of aircraft in the target airspace is also increasing, and it is required to acquire the position information in the target report acquired by the secondary monitoring radar device with higher accuracy. It has become like this. The position information of the aircraft acquired by the secondary monitoring radar device is calibrated with respect to the reference azimuth by the azimuth correction value in which the azimuth information is set in advance as described above.

  However, with respect to the azimuth information as compared with the distance information, a bias error is likely to occur due to electrical and mechanical factors caused by changes in the installation environment of the apparatus and changes over time. Also, in order to reacquire the azimuth correction value to eliminate this type of error, for example, it is necessary to cooperate with the secondary monitoring radar site where the coverage is adjacent, and the azimuth correction value is reacquired by itself. It was not always easy to do. For this reason, if the azimuth information is not sufficiently corrected, the accuracy of the acquired position information will be affected, and the accuracy of the position information in the target report sent to the subsequent stage may not be sufficiently maintained. It was.

  The present embodiment has been made in consideration of the above-described circumstances, and can provide a secondary monitoring radar apparatus that can send a target report having a good position accuracy, and an azimuth correction used for the secondary monitoring radar apparatus. It aims to provide a method.

In order to achieve the above object, the secondary monitoring radar apparatus according to the present embodiment uses the ADS-B signal transmitted from the same aircraft as the position information of the aircraft obtained by receiving the SSR response signal from the aircraft. In the secondary monitoring radar device that corrects and uses the position information received and acquired, edits and outputs the target report of the aircraft including the corrected position information, receives the SSR response signal from the aircraft, An SSR reception processing unit that acquires the position information as an observation position, and an azimuth correction value for correcting the azimuth information in the aircraft position information acquired as the observation position is updated and stored with a secondary correction value. Based on the correction value storage unit and the azimuth correction value stored in the correction value storage unit, the aircraft position information acquired as the observation position is corrected, and the SSR position information is obtained. An SSR position correction unit that operates, a target report editing unit that edits a target report of the aircraft including the SSR position information, and an ADS-B signal transmitted from the aircraft, and receives the position information as ADS-B Based on a comparison result at the same time between the SSR position information of the aircraft and the ADS-B position information, the secondary correction value for updating the azimuth correction value is obtained. A secondary correction value calculation unit that calculates and sends the correction value storage unit to the correction value storage unit, and the secondary correction value calculation unit stores the ADS-B position information of the aircraft in time series, and the stored contents thereof ADS-B position management unit for calculating ADS-B position information of the aircraft at the same time as the time when the SSR position information was acquired based on The SSR position information at the time and the ADS-B position information are compared, and the difference in the azimuth information viewed from the own apparatus is stored as a azimuth deviation in time series along with the passage of the time when the SSR position information is acquired. And calculating the secondary correction value for updating the azimuth correction value stored in the correction value storage unit based on a result of statistical processing of the azimuth deviation stored in the time series. And a correction value calculation unit that sends the correction value to the correction value storage unit.

  Further, the azimuth correction method used in the secondary monitoring radar apparatus of the present embodiment receives the position information of the aircraft obtained by receiving the SSR response signal from the aircraft, and receives the ADS-B signal transmitted from the same aircraft. A direction correction method used in a secondary monitoring radar apparatus that corrects using the position information acquired in this way and edits and outputs the target report of the aircraft including the corrected position information, which is transmitted from the aircraft Receiving the ADS-B signal and storing the position information in time series as ADS-B position information; receiving the SSR response signal from the aircraft; and receiving the position information based on a pre-stored azimuth correction value Obtaining SSR position information corrected for the ADS-B position information of the aircraft at the same time as the time when the SSR position information was acquired Comparing the step of calculating based on the ADS-B position information stored in time series with the SSR position information and the ADS-B position information at the same time of the aircraft, and the difference in the azimuth information seen from the own device As a azimuth deviation, a step of storing the time series of the time when the SSR position information was acquired, a statistical process of the azimuth deviation stored in the time series, and the azimuth based on the processing result A step of calculating a secondary correction value for updating the correction value, and updating the azimuth correction value with the secondary correction value. After the update, the SSR position information is calculated based on the updated azimuth correction value. And a calculating step.

The block diagram which shows an example of a structure of the secondary monitoring radar apparatus of this embodiment. Explanatory drawing which models and shows the calculation timing of azimuth | direction deviation. Explanatory drawing which models and shows secondary correction. FIG. 3 is a first flowchart for explaining the operation of the secondary monitoring radar apparatus illustrated in FIG. 1; FIG. 4 is a second flowchart for explaining the operation of the secondary monitoring radar apparatus illustrated in FIG. 1. The block diagram which shows an example of a structure of the modification of the secondary monitoring radar apparatus illustrated in FIG.

  The best mode for carrying out the secondary monitoring radar apparatus according to the present embodiment and the azimuth correction method used in the secondary monitoring radar apparatus will be described below with reference to FIGS.

  FIG. 1 is a block diagram showing an example of the configuration of the secondary monitoring radar apparatus of the present embodiment. As illustrated in FIG. 1, the secondary monitoring radar device 1 is a system that mainly receives an SSR response signal from the aircraft 10 and edits a predetermined target report while correcting its position information. Antenna 11, SSR receiver 12, SSR position detector 13, operation unit 14, correction value storage unit 15, SSR position corrector 16, target report editor 17, and ADS-B mainly emitted from the same aircraft 10 An ADS-B antenna 21, an ADS-B receiving unit 22, an ADS-B position detecting unit, and a secondary correction value, which is a system for receiving a signal, acquiring its position information, and calculating a secondary correction value to be described later The calculation unit 24 is configured. The SSR reception processing unit corresponds to the SSR antenna 11, the SSR reception unit 12, and the SSR position detection unit 13. The ADS-B reception processing unit corresponds to the ADS-B antenna 21, the ADS-B reception unit 22, and the ADS-B position detection unit 23.

  The SSR antenna 11 receives the SSR response signal from the aircraft 10 and sends it to the SSR receiver 12. The SSR reception unit 12 performs various reception processes on the SSR response signal to decode the response signal content, and also determines the reception time of the SSR response signal and the pointing direction of the SSR antenna 11 at the time of reception by the SSR position detection unit 13. Notify The SSR position detection unit 13 receives these notifications from the SSR reception unit 12 and acquires position information of the aircraft 10 as an observation position as distance and direction information.

  The operation unit 14 is an interface unit that receives various instruction operations by the operator for the secondary monitoring radar apparatus 1, receives an input operation for setting an initial correction value by the operator, and transfers the input operation to the correction value storage unit 15. . For example, a magnetic declination correction value is input as the initial correction value. The correction value storage unit 15 stores the initial correction value as a primary correction value, updates the primary correction value while storing the secondary correction value from the secondary correction value calculation unit described later, The correction value is sent to the SSR position correction unit 16.

  The SSR position correction unit 16 corrects the position information (distance information and azimuth information) of the aircraft 10 acquired as the observation position by the SSR position detection unit 13 based on the azimuth correction value from the correction value storage unit 15. Are sent to the target report editing unit 17 and the secondary correction value calculating unit 24 described later as SSR position information together with the reception time. The target report editing unit 17 edits the target report of the aircraft 10 based on the SSR position information, which is the corrected position information, and the decoding result of the response signal in the SSR receiving unit 12, and sends the target report to the subsequent device. .

  On the other hand, the ADS-B antenna 21 receives the ADS-B signal emitted from the aircraft and sends it to the ADS-B receiving unit 22. The ADS-B receiving unit 22 performs various reception processes on the ADS-B signal and decodes the signal content. The ADS-B position detection unit 23 extracts the position information of the aircraft 10 at the reception time of the ADS-B signal from this decoding result, and sends this to the secondary correction value calculation unit 24 as ADS-B position information. The secondary correction value calculation unit 24 receives the ADS-B position information, accumulates the ADS-B position information sequentially in time series, and statistical processing results of the deviation between the ADS-B position information and the SSR position information for the same aircraft 10 Based on the above, a correction value necessary for correcting the azimuth deviation is calculated and sent to the correction value storage unit 15 as a secondary correction value.

  The secondary correction value calculation unit 24 includes an ADS-B position management unit 241, an azimuth deviation storage unit 242, and a correction value calculation unit 243. The ADS-B position management unit 241 uses the position information of the aircraft 10 acquired by the ADS-B position detection unit 23 as the ADS-B position information together with the acquired time, for example, to draw a wake. ADS-B position information at the designated time is calculated and sent to the position deviation storage unit 242. The azimuth deviation storage unit 242 requires the SSR position information of the aircraft 10 output from the SSR position correction unit 16 and the ADS-B position information of the same aircraft 10 acquired by the ADS-B position detection unit 23 as necessary. Coordinate conversion or the like is performed to convert the distance information and the direction information from the own device position, and comparison is made at the same time, and the difference in the direction information is stored in time series as the direction deviation.

  Here, the relationship between the timing when the position information of the aircraft 10 is acquired by the SSR response signal and the timing acquired by the ADS-B will be described in detail with reference to FIG. The SSR response signal and the ADS-B signal are received asynchronously with each other, and the SSR response signal is received with a longer period. That is, the SSR response signal is a response signal from the aircraft 10 to the SSR inquiry signal from the ground side, and is generally received at a period of several seconds to several tens of seconds as illustrated in FIG. The On the other hand, the ADS-B signal is repeatedly transmitted by the aircraft 10 itself at a cycle of, for example, about 1 second, and the signal is received at the transmission cycle as illustrated in FIG. .

  The azimuth deviation storage unit 242 compares the azimuth information of the position information of the aircraft 10 at the timing detected by the SSR response signal, calculates the deviation, and sequentially stores the calculated azimuth deviation over time. -Accumulated. That is, since the position information acquired by the ADS-B position detection unit 23 at the time of receiving the SSR response signal is necessary for calculating the azimuth deviation, first, the ADS-B position management unit 241 stores the position information in time series. For example, the ADS-B position information at the corresponding time is obtained by extrapolating the set of position information. Then, necessary coordinate conversion or the like is performed on the ADS-B position information, converted into distance information and azimuth information from the own apparatus position, compared with each other, and calculated azimuth deviation (Δθ in FIG. 2) Are sequentially stored and accumulated. As described above, the azimuth deviation storage unit 242 stores the azimuth deviation in the time series of the SSR position information and the ADS-B position information of the same aircraft 10 at the reception time of the SSR response signal as seen from the own apparatus position. Accumulated.

  The correction value calculation unit 243 statistically processes the time-series azimuth deviation stored in the azimuth deviation storage unit 242 and determines the necessity of correction based on the result to calculate a correction value. As a secondary correction value, the correction value is stored in the correction value storage unit 15. In the present embodiment, as statistical processing, for example, the most recent predetermined parameter is extracted from the time-series azimuth deviations stored in the azimuth deviation storage unit 242, and the average value is calculated. When the value exceeds a preset threshold value, it is determined that correction is necessary.

  In the correction, priority is given to the ADS-B position information. That is, as illustrated in FIG. 3, for the azimuth correction so that the corrected position information (SSR position information) of the aircraft 10 output from the SSR position correction unit 16 matches the ADS-B position information. The secondary correction value is calculated. The secondary correction value calculated in this way cancels out error factors such as a bias error that occurs due to, for example, a change in installation environment or aging after the installation of the secondary monitoring radar device. By adding this secondary correction value to the primary correction value (initial correction value) of the azimuth correction, it is always possible to achieve good accuracy with an independent method without the need for cooperation with other secondary monitoring radar sites. The azimuth information can be acquired / maintained at the same time, and the position information of the aircraft 10 output from the SSR position correction unit 16 can also be maintained with good accuracy.

  Next, the operation of the secondary monitoring radar apparatus 1 of the present embodiment configured as described above will be described with reference to FIGS. 1 to 3 and the flowcharts of FIGS. 4 and 5 are flowcharts for explaining the operation of the secondary monitoring radar apparatus 1.

  First, when the apparatus is installed, an initial correction value for azimuth correction is acquired based on fine calibration with respect to the reference azimuth. In this embodiment, the initial correction value is, for example, a magnetic declination correction value, and is sent from the operation unit 14 to the correction value storage unit 15 as a primary correction value by an input operation by an operator or the like and stored. Then, the operation of the apparatus is started and continued using this primary correction value (ST401). Next, in order to compare the detected position of the aircraft based on the SSR response signal and the detected position of the same aircraft based on the ADS-B signal, an aircraft from which position information is to be acquired is designated. When designating the target aircraft, it is verified that the status information regarding the positional accuracy included in the ADS-B signal is particularly good and stable (ST402).

  Next, after the ADS-B signal repeatedly emitted from the target aircraft 10 is received by the ADS-B antenna 21 and subjected to various reception processes by the ADS-B receiver 22 (ST403), the ADS-B position detector In 23, the position information is acquired. The acquired position information is sequentially sent to the secondary correction value calculation unit 24, and is stored in the ADS-B position management unit 241 in time series as ADS-B position information (ST404).

  On the other hand, the SSR response signal is also transmitted from the aircraft 10 asynchronously with these ADS-B signals. This SSR response signal is received by SSR antenna 11, and after reception processing by SSR receiver 12, position information of aircraft 10 at the time of response signal reception is acquired as an observation position by SSR position detector 13 (ST405). Further, the acquired position information as the observation position is corrected based on the azimuth correction value from the correction value storage unit 15 in the SSR position correction unit 16, and the target report editing unit 17 and the secondary correction value as the SSR position information. It is sent to the calculation unit 24. Note that the azimuth correction value from the correction value storage unit 15 applied in the azimuth correction in the SSR position correction unit 16 includes only a primary correction value (initial correction value) or a secondary correction value. In any case, the correction value is updated to a more appropriate correction value by an operation step described later (ST406).

  Next, the secondary correction value calculation unit 24 compares the ADS-B position information and the SSR position information at the same time of the same aircraft, and calculates the secondary correction value by statistically processing the comparison result. That is, since the ADS-B position information and the SSR position information of the same aircraft are acquired at an asynchronous timing, for example, as illustrated in FIG. 2, first, in the ADS-B position information management unit 241, The ADS-B position information at the time when the information is acquired is calculated by extrapolating the time-series ADS-B position information stored therein (ST407).

  Next, the necessary coordinate transformation is performed on the position information, and the azimuth deviation between the two is sequentially calculated by comparison with the same coordinate system, for example, the distance and azimuth from the position of the own apparatus, and the azimuth deviation storage unit It is stored and accumulated in time series at 242 (ST408). Next, in the correction value calculation unit 243, for example, the average value is calculated from the time series azimuth deviations stored in the azimuth deviation storage unit 242, and the preset value is set in advance. It is compared with a threshold value (ST409). When the threshold value is exceeded, it is determined that correction is necessary because the azimuth deviation is large, and a correction value is calculated (Y in ST410). As illustrated in FIG. 3, the calculated correction value is used to eliminate the azimuth deviation so that the SSR position information matches the ADS-B position information, and is corrected from the correction value calculation unit 243 as a secondary correction value. It is sent to the value storage unit 15. In the correction value storage unit 15, the previous azimuth correction value (for example, primary correction value) is updated to a new azimuth correction value by adding this secondary correction value (ST411).

  Thus, the updated azimuth correction value is sent from the correction value storage unit 15 to the SSR position correction unit 16, and thereafter, the SSR position information corrected with the updated azimuth correction value. Based on the above, the target report editing unit 17 edits a predetermined target report. (ST412). Thereafter, the above-described operation steps are repeated until an operation end is instructed.

  As described above, in the present embodiment, the same aircraft as the SSR position information obtained by correcting the observation position of the aircraft detected based on the SSR response signal based on the azimuth correction value stored in advance is spontaneous. ADS-B position information notified to the same time is compared at the same time, and the difference in azimuth when the aircraft is viewed from its own apparatus in both position information is stored and accumulated as azimuth deviation in time series. Then, an average value of the azimuth deviations stored in these time series is calculated, and when the value exceeds a preset threshold value, the azimuth deviation correction is performed so as to match the ADS-B position information. The secondary correction value is calculated and sent to the correction value storage unit 15.

  As a result, in the correction value storage unit 15, the secondary correction value is added to the primary correction value (the previous azimuth correction value), and for example, a bias error in the apparatus due to an environmental change, a secular change, or the like. Since the azimuth correction value is updated so as to be eliminated, the SSR position correction unit 16 can obtain the position information of the aircraft with better accuracy using the updated azimuth correction value. In addition, the direction correction value can be acquired by an independent method without requiring cooperation with other secondary monitoring radar sites or the like. Therefore, a target report having good position accuracy can be edited using this position information, and can be sent to a subsequent device.

Modified example

  FIG. 6 is a block diagram illustrating a configuration of a modified example of the secondary monitoring radar apparatus 1 illustrated in FIG. 1. 6, the same parts as those in FIG. 1 are denoted by the same reference numerals. The secondary monitoring radar device 2 of this modification is different from the secondary monitoring radar device 1 illustrated in FIG. 1 in that an initial correction value for azimuth correction is stored in the correction value storage unit 15 as illustrated in FIG. In the secondary monitoring radar apparatus 1, which is sent from the operation unit 14 to the correction value storage unit 15 based on an input operation by an operator or the like, the secondary monitoring radar apparatus 2 of the modified example illustrated in FIG. A magnetic declination sensor 18 is newly provided, and the magnetic declination correction value acquired by the magnetic declination sensor 18 is sent to the correction value storage unit 15 as an initial correction value (primary correction value) for azimuth correction. This is the point. Hereinafter, the description of the same part is omitted, and the difference will be briefly described.

  As illustrated in FIG. 6, the secondary monitoring radar apparatus 2 newly includes a magnetic declination sensor 18. The magnetic declination sensor 18 acquires the magnetic declination at the installation position of the apparatus and sends this to the correction value storage unit 15 as a magnetic declination correction value. Then, the correction value storage unit 15 stores the correction value from the magnetic declination sensor 18 instead of the correction value from the operation unit 14.

  Next, the operation of the secondary monitoring radar apparatus 2 will be described only with reference to the flowcharts of the secondary monitoring radar apparatus 1 shown in FIGS. 4 to 5. The difference in operation is the operation step of ST401 in FIG. In other words, in the secondary monitoring radar device 2 of this modification, the magnetic declination correction value acquired by the magnetic declination sensor 18 is the correction value as the initial correction value (primary correction value) of the azimuth correction in the operation step of ST401. It is stored in the storage unit 15. The subsequent operation is the same as that of the secondary monitoring radar apparatus 1.

  As described above, also in the secondary monitoring radar apparatus 2 of this modification, the azimuth correction value stored in the correction value storage unit 15 is updated by the ADS-B position information, as in the above-described embodiment. Therefore, the SSR position correction unit 16 can obtain aircraft position information with good accuracy using the updated azimuth correction value. Thereby, the target report which has favorable position accuracy can be edited.

  Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. For example, in the above-described embodiment, the correction value is acquired for one aircraft. However, for example, the correction value is acquired for a plurality of aircraft at the same time, and the results are combined. Can be modified. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1, 2 Secondary monitoring radar device 10 Aircraft 11 SSR antenna 12 SSR receiver 13 SSR position detector 14 Operation unit 15 Correction value storage unit 16 SSR position correction unit 17 Target report editing unit 18 Magnetic declination sensor 21 ADS-B antenna 22 ADS-B receiving unit 23 ADS-B position detecting unit 24 secondary correction value calculating unit 241 ADS-B position managing unit 242 azimuth deviation storage unit 243 correction value calculating unit

Claims (8)

The position information of this aircraft acquired by receiving the SSR response signal from the aircraft is corrected using the position information acquired by receiving the ADS-B signal transmitted from the same aircraft, and the corrected position information is In the secondary monitoring radar device that edits and outputs the target report of the aircraft including
An SSR reception processing unit that receives an SSR response signal from the aircraft and acquires the position information as an observation position;
A correction value storage unit for storing an azimuth correction value for correcting the azimuth information in the position information of the aircraft acquired as the observation position, while updating the secondary correction value;
An SSR position correction unit that corrects the position information of the aircraft acquired as the observation position based on the azimuth correction value stored in the correction value storage unit, and outputs the corrected position information as SSR position information;
A target report editing unit for editing a target report of the aircraft including the SSR position information;
An ADS-B reception processing unit that receives an ADS-B signal transmitted from the aircraft and acquires the position information as ADS-B position information;
A secondary correction value for updating the azimuth correction value is calculated based on a comparison result at the same time between the SSR position information and the ADS-B position information of the aircraft, and is sent to the correction value storage unit. A correction value calculation unit,
The secondary correction value calculation unit
The ADS-B position information of the aircraft is stored in time series, and the ADS-B position information of the aircraft at the same time as the time when the SSR position information is acquired based on the stored contents. A location manager,
The SSR position information and the ADS-B position information at the same time of the aircraft are compared, and the difference of the direction information viewed from the own apparatus is defined as the direction deviation along the passage of the time when the SSR position information is acquired. Azimuth deviation storage unit for storing time series,
Based on the result of statistical processing of the azimuth deviation stored in time series, the secondary correction value for updating the azimuth correction value stored in the correction value storage unit is calculated, and this is calculated as a correction value storage unit A secondary monitoring radar apparatus, comprising: a correction value calculation unit that transmits to
  When calculating the ADS-B position information of the aircraft at the same time as the time when the SSR position information was acquired in the ADS-B position management unit, the ADS-B position up to the most recently stored in the time series The secondary monitoring radar apparatus according to claim 1, wherein the secondary monitoring radar apparatus is calculated by extrapolating information. In the statistical processing in the correction value calculation unit, the average value for the predetermined parameter of the azimuth deviation stored in the time series is calculated, and when the value exceeds a preset threshold value Is a correction value for updating the azimuth correction value stored in the correction value storage unit so that the azimuth information in the SSR position information matches the azimuth information in the ADS-B position information at the same time. The secondary monitoring radar apparatus according to claim 1, wherein the secondary monitoring radar apparatus calculates and sends the result as a secondary correction value to a correction value storage unit.
  The operation unit according to any one of claims 1 to 3, further comprising an operation unit that receives an input operation of the direction correction value by an operator and transfers the operation to the correction value storage unit. Next monitoring radar device.   The magnetic declination sensor according to any one of claims 1 to 3, further comprising a magnetic declination sensor that acquires a magnetic declination and sends the obtained magnetic declination as the azimuth correction value to the correction value storage unit. Secondary monitoring radar equipment. The position information of this aircraft acquired by receiving the SSR response signal from the aircraft is corrected using the position information acquired by receiving the ADS-B signal transmitted from the same aircraft, and the corrected position information is An azimuth correction method used for a secondary monitoring radar apparatus that edits and outputs a target report of the aircraft including:
Receiving an ADS-B signal transmitted from the aircraft and storing the position information in time series as ADS-B position information;
Receiving an SSR response signal from the aircraft and obtaining SSR position information obtained by correcting the position information based on a pre-stored azimuth correction value;
Calculating the ADS-B position information of the aircraft at the same time as the time when the SSR position information was acquired based on the ADS-B position information stored in the time series;
The SSR position information and the ADS-B position information at the same time of the aircraft are compared, and the difference of the direction information viewed from the own apparatus is defined as the direction deviation along the passage of the time when the SSR position information is acquired. Memorizing in time series;
Statistically processing the azimuth deviation stored in the time series, and calculating a secondary correction value for updating the azimuth correction value based on the processing result;
A secondary monitoring radar apparatus comprising: updating the azimuth correction value with the secondary correction value, and calculating the SSR position information based on the updated azimuth correction value after the update. Orientation correction method used for   When calculating the ADS-B position information of the aircraft at the same time as the time when the SSR position information was acquired, the calculation is performed by extrapolating the most recent ADS-B position information stored in the time series. An azimuth correction method used for the secondary monitoring radar apparatus according to claim 6.   In the statistical processing of the azimuth deviation stored in the time series, the average value for a predetermined parameter of these azimuth deviations is calculated, and when the value exceeds a preset threshold value, A correction value for updating the azimuth correction value is calculated so that the azimuth information in the SSR position information matches the azimuth information in the ADS-B position information at the same time. The azimuth | direction correction method used for the secondary monitoring radar apparatus of Claim 6 or Claim 7 characterized by the above-mentioned.