JP5682930B2 - Tracking antenna device and tracking antenna control method - Google Patents

Description

  The present invention relates to a tracking antenna device and a tracking antenna control method in a mobile satellite communication earth station.

  Since satellite communication has a wide service area, it is widely used in mobile bodies such as marine vessels, aircraft, and trains where it is difficult to use ground lines. However, geostationary satellites used in broadband communications and the like are arranged at geostationary orbits at intervals of 2 to 4 degrees, and there is a risk of interference with other satellites if the antenna direction of the earth station deviates. is there. On the other hand, geostationary satellites are 36,000 km away from the ground and have a very large propagation loss. For example, when using the Ku band, which provides services to ships, it is necessary to use a large antenna of at least 60 cm or more. However, the directivity of an antenna of this size is sharp and the beam width becomes as narrow as about 2 degrees. For this reason, when installing an earth station antenna device on a mobile object such as a ship, aircraft, or train, a tracking mechanism that mechanically controls the antenna directivity (elevation angle and azimuth angle) is provided. A tracking antenna device is used in which the antenna is always directed in the satellite direction with respect to fluctuations (Non-Patent Document 1).

  In order to improve the communication speed, it is necessary to improve the performance of the earth station such as an antenna device. As a technique for easily realizing this, an antenna device that cooperates a plurality of tracking antennas has been studied (Non-Patent Document 2). The cooperative operation of the plurality of tracking antennas improves the antenna gain and improves the shielding resistance.

Higaki, Tsuchiya, “Design method of vibration isolation mechanism and tracking control system for marine broadband antenna”, IEICE Transactions 2008/12 Vol.J91-B No.12 Susaki, Suzuki, Yamashita, Kobayashi, “Examination of tracking antenna for shipboard earth station using multiple antennas”, 2010 IEICE Society Conference B-3-19 4-3-12 Selecting the operation location p.29 www.lascom.or.jp/member/iomver/iomver4 303.pdf

  For example, when installing a tracking antenna device on a ship, considering the ship's position (latitude / longitude), azimuth, and inclination of the ship due to shaking, the azimuth angle is 360 degrees and the elevation angle is 0-90 degrees. It is desirable to install it in a place where it can be secured. However, depending on the structure of the ship, the tracking antenna may not be installed in a place where such a line of sight can be secured. Therefore, if a ship structure blocks an electric wave as an obstacle between the satellite direction and the tracking antenna, communication cannot be performed.

  In response to such a problem, by providing a plurality of tracking antennas on the earth station side for one satellite, even if some tracking antennas are shielded by obstacles, communication is performed using other tracking antennas. A way to maintain is considered. However, unnecessary waves are not radiated in the direction of other satellites due to reflection / diffraction by obstacles, so if there is an obstacle within 3 degrees when looking at the satellite direction from the tracking antenna, the communication signal is stopped. Is taken (Non-Patent Document 3). For this reason, even if a plurality of tracking antennas are provided for one satellite, it is not always possible to secure a line of sight in all directions, and there may be a time during which communication cannot be performed for a certain period of time.

  On the other hand, there is a case where a backup satellite for securing a backup line is prepared for a working satellite for which a communication line is set. In such a configuration, when the communication line is interrupted due to blocking by an obstacle, the tracking antenna is controlled to search for a backup satellite, and the communication is continued by switching to the secured backup line. Communication is interrupted. Note that tracking antennas used in satellite communications have sharp directivity because radio waves are weaker than terrestrial antennas such as wireless LANs and mobile phones. Therefore, since it is basically impossible to track a plurality of satellites with one tracking antenna, a communication stop accompanying satellite switching is inevitable.

  The present invention utilizes a plurality of tracking antennas and a plurality of satellites (current satellites and backup satellites) provided in a moving body, always adopts a redundant configuration of a communication line and a backup line, and can improve the communication operation rate. An object is to provide an antenna device and a tracking antenna control method.

A first aspect of the present invention is directed to a first satellite used in a communication line among a plurality of satellites in the orientation of the plurality of tracking antennas that the installed earth station to the mobile is provided to back up the relationship with each other, one tracking A communication line is set between the antenna and the first satellite, a backup line is set between the other tracking antenna and the first satellite, and the line can be switched between the communication line and the backup line. In the tracking antenna device, it is sequentially determined whether or not a line of sight with respect to the first satellite is secured from the plurality of tracking antennas, and one tracking antenna with the line of sight with respect to the first satellite is secured. A communication line is set up with the first satellite, a backup line is set up between the other tracking antenna and the first satellite with a view to the first satellite, and the first satellite is seen. Tracking antenna control means with teeth to set a new backup line between the other tracking antenna and the second satellite prospects for a second satellite in the backup of the relationship between the first satellite is not ensured is ensured Is provided.

  In the tracking antenna device of the first invention, the tracking antenna control means includes a plurality of tracking antennas based on posture / position sensor information indicating the position, azimuth, and posture of the moving body, and shape data of a structure constituting the moving body. An angle between the pointing direction from the antenna to the first satellite and the outline of the structure is calculated, and it is determined that a line-of-sight with respect to the first satellite is not secured for the tracking antenna having the angle smaller than a predetermined threshold.

  In the tracking antenna device according to the first aspect, the tracking antenna control means detects the reception signal levels of the plurality of tracking antennas, and the tracking antenna has an average value of the reception signal levels that is smaller than a predetermined reference value. Judge that the outlook for the satellite is not secured.

The second invention is directed to a first satellite used in a communication line among a plurality of satellites in the orientation of the plurality of tracking antennas that the installed earth station to the mobile is provided to back up the relationship with each other, one tracking A communication line is set between the antenna and the first satellite, a backup line is set between the other tracking antenna and the first satellite, and the line can be switched between the communication line and the backup line. In the tracking antenna method, the tracking antenna control means sequentially determines whether or not a line of sight with respect to the first satellite is secured from the plurality of tracking antennas, and one tracking antenna with the line of sight with respect to the first satellite is secured. Set up a communication line between the first satellite and the first satellite, set up a backup line between the other tracking antenna and the first satellite with a view to the first satellite, One new backup line between the first first second other tracking antenna and the second satellite prospect is secured relative to the satellites in the relationship of the satellite backup without sight is secured relative to the satellites Set .

  In the tracking antenna control method according to the second aspect of the invention, the tracking antenna control means includes a plurality of tracking antenna control means based on posture / position sensor information indicating the position, azimuth, and posture of the moving body, and shape data of the structure constituting the moving body. The angle between the pointing direction from the tracking antenna to the first satellite and the outline of the structure is calculated, and it is determined that the line of sight with respect to the first satellite is not secured for the tracking antenna whose angle is smaller than a predetermined threshold. .

  In the tracking antenna control method according to the second invention, the tracking antenna control means detects the reception signal levels of the plurality of tracking antennas respectively, and the tracking antenna has a first value for the tracking antenna whose average value of the reception signal levels is smaller than a predetermined reference value. Judging from the prospects for future satellites.

  The present invention prepares a backup line with another satellite when the structure of the moving object becomes an obstacle in the direction of the tracking antenna and the line of sight with the satellite cannot be secured. In addition, a redundant configuration is possible between a plurality of tracking antennas and a plurality of satellites, and the communication operation rate can be improved. Conventionally, tracking antennas had to secure line-of-sight in all directions, but multiple tracking antennas only need to be able to secure line-of-sight individually for multiple satellites. The degree of freedom can be improved.

It is a figure which shows the outline | summary of Example 1 of the tracking antenna apparatus of this invention. It is a figure which shows the structural example of Example 1 of the tracking antenna apparatus of this invention. It is a flowchart which shows the example of a process sequence of Example 1 of the tracking antenna apparatus of this invention. It is a figure which shows the outline | summary of Example 2 of the tracking antenna apparatus of this invention.

FIG. 1 shows an outline of a tracking antenna device according to a first embodiment of the present invention.
FIG. 1 (1) shows a normal state, and there is a line of sight of the satellite (working satellite) 1 from a plurality (two in this case) of the tracking antennas 11 and 12, and between the tracking antennas 11 and 12 and the satellite 1 A redundant configuration is used for communication. In a redundant configuration with two tracking antennas and one satellite, one tracking antenna is used as a communication line and the other tracking antenna is used as a backup line. However, two tracking antennas are linked as in the prior art. It may be configured to operate so that the transmission EIRP and the reception G / T are maximized and optimized.

  Here, as shown in FIG. 1 (2), when one tracking antenna 12 is blocked by an obstacle on the ship due to a change in position or direction of the ship or shaking, the tracking antenna 12 is not connected to another satellite ( The backup satellite) 2 is controlled to secure a backup line. That is, while maintaining a communication line between the tracking antenna 11 and the satellite 1, a redundant configuration is taken with the tracking antenna 12 and the satellite 2 as a backup line. Thereby, even if the tracking antenna 11 and the satellite 1 are subsequently blocked, switching to the backup line between the tracking antenna 12 and the satellite 2 can prevent the complete communication line of the entire system from being interrupted. .

  If the blocking between the tracking antenna 12 and the satellite 1 is temporary, a backup line may be reset between the tracking antenna 12 and the satellite 1. Further, the tracking antenna 11 and the satellite 1 are blocked, and after the communication line is shifted between the tracking antenna 12 and the satellite 2, a backup line is set between the tracking antenna 11 and the satellite 2. Also good.

FIG. 2 shows a configuration example of the tracking antenna device according to the first embodiment of the present invention.
In FIG. 2, the tracking antenna apparatus according to the first embodiment receives tracking antennas 11 and 12 having a satellite tracking function, and received signals from the tracking antennas 11 and 12, and outputs tracking control signals to the tracking antennas 11 and 12. The tracking antenna control device 20 is configured. The tracking antenna control device 20 includes satellite links / tracking control units 21 and 22, a position / attitude sensor 23, a data memory 24, and a blocking occurrence detection unit 25 corresponding to the tracking antennas 11 and 12, respectively.

  The position / orientation sensor 23 is a GPS sensor or a gyro sensor attached to the ship or the tracking antenna device itself, and outputs position (latitude / longitude) information and attitude (azimuth and inclination) information of the tracking antennas 11 and 12. The data memory 24 stores shape data of the ship structure.

  The blocking occurrence detection unit 25 inputs the received signal level of the tracking antennas 11 and 12, the position information and attitude information of the tracking antennas 11 and 12, and the shape data of the structure of the ship, and the tracking antennas 11 and 12 and the satellite 1 When it is detected whether the line of sight can be secured, that is, when the occurrence of blocking accompanying the movement or swinging of the ship is detected, the satellite line / tracking control unit for the tracking antenna in which the blocking has occurred is notified. The satellite line / tracking control unit that has received the notification searches for another satellite 2 for the tracking antenna whose line-of-sight cannot be secured, and sends a command to secure the control line.

  For example, as shown in FIG. 1 (2), the distance between the pointing direction of the tracking antenna 12 and the outline of the structure is less than x degrees (x is set during operation, 3 degrees in Non-Patent Document 3), or If the average received signal level is y times the reference value (0 ≦ y <1, y is set during operation), blocking is considered to be impossible to communicate, and tracking is performed via the satellite line / tracking control unit 22. A command is sent to the antenna 12 to search for another satellite 2. The tracking antenna 12 that has received the command searches the satellite 2 and secures a control line.

  FIG. 3 shows a processing procedure example of the tracking antenna device according to the first embodiment of the present invention. Hereinafter, a case where a line of sight between the tracking antenna 12 and the satellite 1 cannot be secured will be described as an example with reference to FIGS.

  There is a line of sight between the tracking antennas 11 and 12 and the satellite 1, and the tracking antennas 11 and 12 and the satellite 1 have a communication line and a backup line in a redundant configuration, or perform communication in cooperation ( S1). At this time, the blocking occurrence detection unit 25 acquires the received signal level and position / posture information of the tracking antennas 11 and 12 (S2), and whether or not the line of sight between the tracking antennas 11 and 12 and the satellite 1 is secured. Whether or not blocking has occurred is confirmed (S3). Here, when both tracking antennas 11 and 12 have a line-of-sight between the satellites 1 (S3: Yes), communication between the tracking antennas 11 and 12 and the satellites 1 through a redundant configuration or cooperative operation is performed. Continue (S1).

  On the other hand, in the tracking antennas 11 and 12, here, it is detected from the received signal level of the tracking antenna 12 and the position / posture information that blocking has occurred due to an obstacle between the tracking antenna 12 and the satellite 1 ( (S3: No), communication is continued between the tracking antenna 11 and the satellite 1 (S4), and the backup satellite 2 for the satellite 1 is searched from the tracking antenna 12 to secure a control line (S5).

  Next, the blocking occurrence detection unit 25 acquires the received signal level and position / posture information of the tracking antenna 11 (S6), and the line-of-sight between the tracking antenna 12 and the satellite 1 that has lost line-of-sight with the satellite 1 is restored. Then, it is confirmed whether or not improvement of the reception status can be expected (S7), and further, it is confirmed whether or not a line of sight between the tracking antenna 11 and the satellite 1 is secured (S8). Here, when the line-of-sight between the tracking antenna 12 and the satellite 1 can be recovered (S7: Yes), the tracking antenna 12 and the satellite 1 are reconnected (S9), and the tracking antennas 11 and 12 and the satellite 1 are connected. The communication returns to the redundant configuration or the communication by the cooperative operation (S1).

  On the other hand, if the line-of-sight between the tracking antenna 12 and the satellite 1 cannot be recovered (S7: No), and the line-of-sight between the tracking antenna 11 and the satellite 1 can be secured (S8: Yes), the tracking antenna 11 And communication with the satellite 1 is continued. Here, when the line-of-sight between the tracking antenna 11 and the satellite 1 cannot be secured (S8: No), the communication shifts to the communication between the tracking antenna 12 and the satellite 2 (S10). Further, the satellite 2 is searched from the tracking antenna 11 to secure a control line (S11), and then communication is performed between the tracking antennas 11 and 12 and the satellite 2 in a redundant configuration or cooperative operation (S12).

  In the first embodiment described above, the two tracking antennas 11 and 12 and the two satellites 1 and 2 are used. However, the same control is performed even when three or more tracking antennas and three or more satellites are used. In that case, communication may be performed by selecting a combination of a tracking antenna and a satellite with the best communication status or the best communication speed.

FIG. 4 shows an outline of Embodiment 2 of the tracking antenna apparatus of the present invention.
The tracking antenna 13 of the second embodiment shown in FIG. 4 (1) uses, for example, a phased array antenna that can freely control the antenna pattern electrically, and communicates with the satellite 1 while also transmitting a weak beam to the satellite 2. Redundant configuration to be directed. In this case, although there is only one tracking antenna, a function equivalent to a configuration using a plurality of tracking antennas substantially the same as in the first embodiment can be realized.

  Here, as shown in FIG. 4 (2), when the communication status with the satellite 1 deteriorates, the main beam directed to the satellite 1 and the weak beam directed to the satellite 2 are switched, and the main beam is transmitted to the satellite 2. The satellite 1 is quickly handed over by forming a null or the like.

  This embodiment can also be applied to a configuration using two or more tracking antennas (phased array antennas) and three or more satellites.

1, 2 Satellites 11, 12 Tracking antenna 13 Tracking antenna (phased array antenna)
20 Tracking Antenna Control Device 21, 22 Satellite Link / Tracking Control Unit 23 Position / Attitude Sensor 24 Data Memory 25 Blocking Occurrence Detection Unit

Claims (6)

Towards the first satellite using a pointing direction of a plurality of tracking antennas that the installed earth station to the mobile is provided to a communication line among a plurality of satellites in the backup relationship to each other, wherein as one of the tracking antenna first A communication line is set up with the other satellite, a backup line is set up between the other tracking antenna and the first satellite, and the line can be switched between the communication line and the backup line. In the tracking antenna device,
It is sequentially determined whether or not a line of sight with respect to the first satellite is secured from the plurality of tracking antennas, and the one tracking antenna with the line of sight with respect to the first satellite secured and the first satellite The communication line is set between the other tracking antenna and the first satellite having a line-of-sight with respect to the first satellite, and the first satellite is set. Tracking for setting a new backup line between the other tracking antenna and the second satellite in which the prospect for the second satellite in the relationship of backup of the first satellite is not secured and the prospect for the second satellite is secured A tracking antenna device comprising an antenna control means. The tracking antenna device according to claim 1,
The tracking antenna control means, based on posture / position sensor information indicating the position, azimuth, and posture of the moving body, and shape data of a structure constituting the moving body, from the plurality of tracking antennas, Calculating an angle between a pointing direction with respect to a satellite and an outline of the structure, and determining that a line-of-sight with respect to the first satellite is not secured for a tracking antenna having the angle smaller than a predetermined threshold. Tracking antenna device. The tracking antenna device according to claim 1,
The tracking antenna control means detects the reception signal levels of the plurality of tracking antennas, respectively, and the tracking antenna having an average value of the reception signal levels smaller than a predetermined reference value does not ensure a line of sight with respect to the first satellite. A tracking antenna device characterized by judging. Towards the first satellite using a pointing direction of a plurality of tracking antennas that the installed earth station to the mobile is provided to a communication line among a plurality of satellites in the backup relationship to each other, wherein as one of the tracking antenna first A communication line is set up with the other satellite, a backup line is set up between the other tracking antenna and the first satellite, and the line can be switched between the communication line and the backup line. In the tracking antenna method,
With tracking antenna control means,
Sequentially determining whether or not a line of sight to the first satellite is secured from the plurality of tracking antennas,
Setting the communication line between the one tracking antenna and the first satellite in which a line of sight with respect to the first satellite is secured;
The backup line is set between the other tracking antenna and the first satellite for which the line of sight with respect to the first satellite is secured, and the line of sight with respect to the first satellite is not secured . A tracking antenna method, wherein a new backup line is set between the second satellite and the other tracking antenna that secures a line of sight to the second satellite in a satellite backup relationship. In the tracking antenna control method according to claim 4,
The tracking antenna control means, based on posture / position sensor information indicating the position, azimuth, and posture of the moving body, and shape data of a structure constituting the moving body, from the plurality of tracking antennas, Calculating an angle between a pointing direction with respect to a satellite and an outline of the structure, and determining that a line-of-sight with respect to the first satellite is not secured for a tracking antenna having the angle smaller than a predetermined threshold. Tracking antenna control method. In the tracking antenna control method according to claim 4,
The tracking antenna control means detects the reception signal levels of the plurality of tracking antennas, respectively, and the tracking antenna having an average value of the reception signal levels smaller than a predetermined reference value does not ensure a line of sight with respect to the first satellite. A tracking antenna control method characterized by determining.

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