JP2011208998A - Gps signal receiving means of satellite communication device for ship - Google Patents

Abstract

【Task】
When a structure such as a ship-mounted object exists in the direction of the antenna of the GPS receiver, there is a problem that this becomes a blocking object and a signal cannot be received from a GPS satellite.
[Solution]
In the case where the communication antenna and the GPS antenna are fixed to the rotating device and the positional relationship between them is fixed, when the shipboard satellite communication shipboard device is equipped, the GPS is shielded by the structure on the ship. A means for storing the azimuth angle of the communication antenna that prevents the GPS antenna from receiving a signal from the satellite and storing it in a storage device, and the azimuth of the communication antenna when the GPS antenna receives a signal from the GPS satellite When the angle is within the range described by the database, the communication satellite and the GPS antenna are rotated in a horizontal plane, so that the GPS satellite viewed from the GPS antenna is within a viewing angle. And
[Selection] Figure 7

Description

The present invention relates to a bow heading indexing system for transmitting and receiving radio waves from a geostationary satellite, and is useful when GPS is used as the bow heading indexing method.

  In a satellite automatic tracking device for a satellite communication antenna mounted on a conventional mobile body (vehicle, ship, etc.), a sensor such as an inclinometer and a magnetic compass or a gyrocompass is used as a sensor for determining the azimuth angle and tilt angle of the mobile body itself. Are used in combination.

For the target angle to the communication satellite, the operator obtains the latitude and longitude based on the map information, calculates the target angle from the value and inputs it to the control unit of the rotary head, or the global positioning system (hereinafter referred to as GPS). ) A method of taking a received signal, recognizing its own position, and calculating a target angle is used. In capturing satellites when operating in a stationary state, it is often the case that the direction of the antenna is finely adjusted by hand while observing the level of the received signal.

  As an example, FIG. 1 shows a configuration diagram of a mobile-mounted satellite automatic tracking device using an inclinometer and a gyrocompass. 1 uses a gyro compass 6 capable of detecting an inclination angle and an azimuth angle as a sensor unit and a biaxial inclinometer 5 for correcting the accuracy of the inclination angle. Similarly, the detected value is output to the control unit 4.

Similarly, the signal of the GPS receiver 7 is also taken into the control unit 4 and calculated as the detection value of the sensor unit, the target azimuth angle and the vertical attack angle to the target communication satellite are obtained, and the rotary head 2 is moved to the target angle Control and drive and capture the satellite radio wave with the antenna 1 pointing toward the satellite. The captured satellite radio wave is processed by the modem unit 3 into an I / F signal suitable for the target operational equipment.

Thus, in a moving object equipped with a gyrocompass, since the gyrocompass indicates the heading, the direction of the antenna can be directed to the satellite using this angle, and if the gyrocompass is not installed, A method is used in which the elevation angle of the antenna with respect to the satellite is obtained from the GPS positioning value, the reception intensity is measured while rotating the antenna, and the direction in which the radio wave is strong is searched.

As another satellite tracking method, for example, Patent Document 1 describes means for searching for a satellite having a maximum frequency offset in order to know which satellite is optimal to use. Patent Document 2 describes means for using a GPS, a 2-axis inclinometer, and a 3-axis rate gyro to perform satellite tracking.

JP 2000-59281 A JP 2005-300347 A

However, according to the conventional means, as shown in FIG. 2, when there is a structure 10 such as a ship-mounted object in the direction of the antenna 9 of the GPS receiver, it becomes a shield and receives signals from GPS satellites. It becomes a blocking state that can not be done. In the figure, 1 is a communication antenna and 8 is a pedestal of an antenna device.

Thus, if there is a shield in the direction of the GPS antenna, positioning using the GPS receiver cannot be performed, and setting of the bearing angle of the antenna 1 becomes impossible. The meaning of the bearing angle is shown in FIG.

As shown in the figure, with respect to the ship 11, the bow direction seen from the true north direction is called a heading angle, and the azimuth direction of the satellite position seen from the bow direction is called a bearing angle. In other words, if positioning by GPS cannot be performed due to blocking, the position of the ship itself is not known, and setting of the bearing angle, which is the difference between the bow direction and the satellite position, becomes impossible.

In order to solve the above problems, the present invention provides:
In the case of a marine satellite communication onboard device, in which the communication antenna and the GPS antenna are fixed to the rotating device, and each positional relationship is fixed,
When the shipboard satellite communication shipboard device is equipped, the azimuth angle of the communication antenna that makes it impossible for the GPS antenna to receive signals from GPS satellites due to shielding of structures on the ship is made into a database and stored in a storage device. Means to keep
When the GPS antenna receives a signal from the GPS satellite and the azimuth angle of the communication antenna is within the range described by the database, the communication antenna and the GPS antenna are placed on a horizontal plane. Means for rotating to cause the GPS satellite as seen from the GPS antenna to lie within an angle of view;
A GPS signal receiving means for a marine satellite communication onboard device.

In the present invention, when creating the database,
The communication antenna and the GPS antenna fixed to the rotating device rotate around the rotation axis of the rotating device, and the received signal intensity according to the azimuth angle of the communication antenna from the GPS satellite to the GPS antenna When the received signal strength is equal to or less than a predetermined threshold value, the azimuth angle of the communication antenna is recorded.

According to the present invention, since the blocking state can be avoided in the GPS positioning, it is not necessary to wait until the blocking state is released, so that the GPS positioning time can be shortened.

In addition, since there is no significant fluctuation in the GPS reception intensity, it is not difficult to determine the positioning result, and therefore a search for the entire circumference of the communication antenna due to the fact that the position of the ship cannot be determined becomes unnecessary. The all-round search of the communication antenna is to rotate the communication antenna 360 degrees in order to find a direction in which the intensity of the received radio wave from the communication satellite is maximized.

Conventional satellite search means Positioning impossible due to blocking Explanation of terminology for angle State of blocking state avoidance according to the present invention GPS antenna position according to azimuth angle of communication antenna Initial work when installing ADE GPS antenna blocking avoidance routine

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As an embodiment, satellite communication in a ship is taken as an example, and FIG. 4 is a diagram showing a state of avoiding a blocking state according to the present invention. For example, when the communication antenna 1 installed in the pedestal 8 is directed to the communication satellite, the GPS antenna 9 installed in a part of the communication antenna device with respect to the GPS satellite as shown in FIG. 13 and FIG. May fall into the shadow of the shield 10.

As shown in FIG. 15, the present invention relates to means for rotating the communication antenna device in the AZ plane and bringing the GPS antenna out of the shield when performing GPS communication.

This will be further described with reference to FIG. In FIG. 5A, the communication antenna 1 faces the bow direction, and the GPS antenna 9 is in the shadow of the structure 10. In FIG. 5B, the communication antenna 1 is rotated by θb with respect to the bow direction, and the GPS antenna 9 is in the shadow of the structure 10. In FIG. 5C, the communication antenna 1 is rotated by θc, and the GPS antenna 9 is not in the shadow of the structure 10.

Thus, in the present invention, when the GPS antenna 9 necessary for acquiring the traveling direction (heading angle) of the ship is in the shadow of the structure 10, the communication antenna 1 is rotated by θc to A GPS antenna 9 connected to the communication antenna 1 is placed out of the shadow of the structure 10.

As described above, in order to prevent the GPS antenna from being unable to receive the GPS satellite signal due to the directivity azimuth angle of the communication antenna 1, the initial setting performed when the marine satellite communication onboard device (ADE) is installed is illustrated in FIG. A flowchart is shown in FIG.

First, the ADE is installed on the ship (S61). Next, while rotating the communication antenna (S62), the signal level received by the GPS antenna from the GPS satellite is compared with a predetermined threshold value (S63). Here, if the reception level is equal to or lower than the threshold value, it is determined that the GPS antenna is in the shadow of the structure, and the rotation angle of the communication antenna at that time is stored (S64). This process completes the range database 16 for determining whether the GPS antenna is in a blocking state with respect to the rotation angle of the communication antenna in the azimuth direction.

A processing procedure for avoiding the blocking state of the GPS antenna using the database 16 is shown in the flowchart of FIG.

When the power of the ADE is turned on (S71), first, the ADE performs AZ axis origin detection processing where it is the azimuth plane (S72). The origin detection in the moving body means that the device is directed in the moving direction, that is, in this case, the antenna surface is directed in the bow direction. As the origin detection method, various methods such as acquiring the direction of acceleration with a gyro sensor are conceivable, but the present invention is not limited to this.

Then, when the communication antenna is directed in a direction in which transmission / reception with the communication satellite can be performed, the GPS antenna attached to the communication antenna may enter the shadow of the structure as shown in FIG. When it is necessary to receive a GPS signal (S73), the range data database 16 stores the view of the GPS antenna over the sky according to the direction of the communication antenna as described above. The azimuth angles of the communication antennas are compared (S74).

Note that there are various situations where it is necessary to receive a GPS signal, for example, when it is necessary to know the latitude and longitude of a moving object, or when it is necessary to obtain an accurate time. However, the use of the GPS signal is not limited.

If the communication antenna is outside the range data, the GPS antenna receives the GPS signal as it is (S76). If the communication antenna is within the range data, the communication antenna is rotated to the maximum on the AZ axis (S75), for example. To improve the view to the sky.

It should be noted that a method of minimizing the rotation angle of the communication antenna is conceivable as to how many times the communication antenna is tilted to improve the view from above the GPS antenna. In the present invention, the rotation angle of the communication antenna is not limited to this. Is not limited.

As described above, the present invention creates a database in advance as to whether or not a GPS antenna and a GPS satellite can communicate with each other when a radio wave is blocked by a structure. GPS satellite communication is always possible, and can be used as means for ensuring continuity of communication.

DESCRIPTION OF SYMBOLS 1 ... Communication antenna, 2 ... Rotating pan head, 3 ... Modulation / demodulation part,
4 ... control unit, 5 ... biaxial inclinometer, 6 ... gyro compass,
7 ... GPS receiver, 8 ... Pedestal, 9 ... GPS antenna,
10 ... structure, 11 ... own ship, 12 ... communication satellite,
13 ... View from the side of the GPS antenna in the shadow of the structure,
14: A top view of the GPS antenna in the shadow of the structure,
15 ... View from above of moving the GPS antenna so that it does not become a shadow of the structure,
16 ... blocking range database,

Claims (2)

In the case of a marine satellite communication onboard device, in which the communication antenna and the GPS antenna are fixed to the rotating device, and each positional relationship is fixed,
When the shipboard satellite communication shipboard device is equipped, the azimuth angle of the communication antenna that makes it impossible for the GPS antenna to receive signals from GPS satellites due to shielding of structures on the ship is made into a database and stored in a storage device. Means to keep
When the GPS antenna receives a signal from the GPS satellite and the azimuth angle of the communication antenna is within the range described by the database, the communication antenna and the GPS antenna are placed on a horizontal plane. Means for rotating to cause the GPS satellite as seen from the GPS antenna to lie within an angle of view;
A GPS signal receiving means for a marine satellite communication shipboard device, characterized by comprising: When creating the database according to claim 1,
The communication antenna and the GPS antenna fixed to the rotating device rotate around the rotation axis of the rotating device, and the received signal intensity according to the azimuth angle of the communication antenna from the GPS satellite to the GPS antenna GPS signal receiving means for a shipboard satellite communication shipboard device, wherein the azimuth angle of the communication antenna is recorded when the received signal strength is less than or equal to a predetermined threshold value.