JP2003309415A - Satellite acquisition system for on-vehicle relay station and satellite acquisition method for on-vehicle relay station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a satellite acquisition system capable of reliably and automatically directing an on-vehicle station antenna to an acquisition object satellite. <P>SOLUTION: The satellite acquisition system is provided with: a beacon reception discrimination apparatus 7 for discriminating a beacon signal from the acquisition object satellite on the basis of a reception frequency and a reception level; an antenna controller 6 for calculating an azimuth angle and an elevating angle on the basis of positional information of an on-vehicle station 10 and the acquisition object satellite 1; and an antenna driver 5 for driving an antenna 2. The antenna driver 5 drives the antenna 2 within a first angular rang around the azimuth angle calculated by the antenna controller 6, and the antenna 2 locks on the beacon signal on the basis of a discrimination signal from the beacon reception discrimination apparatus 7. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite acquisition system for an on-vehicle relay station and a satellite acquisition method for an on-vehicle relay station, and more particularly, to automatically direct an antenna of an on-vehicle satellite communication station to an acquisition target satellite. The present invention relates to a satellite acquisition system and method.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a configuration of a conventional satellite acquisition system, showing an on-vehicle relay station for satellite communication. In the figure, 1 is a communication satellite, 2 is an in-vehicle station antenna, 3 is a power feeding device, 4 is a transmitting / receiving device, 5 is an antenna driving device, 6 is an antenna control device, 8 is a spectrum analyzer, and 10 is a satellite communication in-vehicle station. .

After arriving at the relay site, the vehicle-mounted station 10 must first direct the vehicle-mounted station antenna 2 to the communication satellite 1 (capture target satellite) to be captured. Therefore, the onboard station operator inputs the position information of the satellite 1 to be captured and the onboard station 10 to the antenna control device 6. The antenna control device 6 calculates the azimuth angle and the elevation angle of the vehicle-mounted station antenna 2 with respect to the capture target satellite 1 based on the position information input by the operator. The antenna driving device 5 drives the vehicle-mounted station antenna 2 based on the calculated azimuth angle and elevation angle, and directs the vehicle-mounted station antenna 2 to the capture target satellite 1.

However, the communication satellite 1 is moving slightly but constantly. Further, when transmitting and receiving a signal of 10 GHz or more, a parabolic antenna with high directivity is used as the vehicle-mounted station antenna 2, but its reception beam width (half-value width) is about 1 degree or less, which is very narrow. Furthermore, there is a limit to the detection accuracy of the angle detection mechanism of the antenna 2. Therefore,
Even if the above-mentioned antenna control method is used, it is not possible to accurately drive and control the vehicle-mounted station antenna 2 so that the capture target satellite 1 is at the true center position of the beam of the vehicle-mounted station antenna 2. It was

For this reason, the conventional on-vehicle station operator finally monitors the reception carrier from the satellite 1 to be captured by using the spectrum analyzer 8 and azimuth / elevation angle of the antenna 2 so that the reception level becomes maximum. Were manually adjusted to direct the beam to the beam center position of the satellite 1 to be captured.

[0006]

As described above, in the conventional satellite acquisition system, when the on-vehicle station antenna is directed to the satellite to be acquired, the on-vehicle station operator manually finely adjusts the on-vehicle station antenna. Was there. Therefore, it takes a considerable time (for example, about 15 minutes) from when the vehicle-mounted station arrives at the site to start the relay. In addition, it is not possible to determine whether or not the satellite to be captured is actually captured only by observing the received carrier from the communication satellite with a spectrum analyzer, and there is a possibility of causing an operational error that the satellite not to be captured is mistakenly captured. It was Therefore, for satellite acquisition,
Quite skilled operators were needed.

The present invention has been made to solve the above problems, and provides a satellite acquisition system and a satellite acquisition method capable of directing an on-vehicle station antenna to an acquisition target satellite in a short time. The purpose is to Another object of the present invention is to provide a satellite acquisition system and a satellite acquisition method that do not mistakenly acquire satellites that are not targets for acquisition. Another object of the present invention is to provide a satellite acquisition system and a satellite acquisition method that can automatically orient an on-vehicle station antenna to a satellite to be acquired.

[0008]

A satellite acquisition system for an on-vehicle relay station according to the present invention according to claim 1 acquires an antenna for receiving a beacon signal transmitted from a communication satellite, and an acquisition based on a reception frequency and a reception level. A beacon reception determination device that determines a beacon signal from a target satellite, an antenna control device that calculates an azimuth angle and an elevation angle based on position information of an in-vehicle station and a capture target satellite, and an antenna drive device that drives an antenna, By automatically driving the satellite to be captured by driving the antenna within the first angle range centered on the azimuth calculated by the antenna control device and locking on the beacon signal based on the determination signal from the beacon reception determination device. Configured to capture.

According to a second aspect of the present invention, there is provided a satellite acquisition system for a vehicle-mounted relay station, which locks on a beacon signal of a satellite to be acquired, and then an antenna within a second angle range narrower than the first angle range. Is configured to be driven to perform a peak search.

According to a third aspect of the present invention, there is provided a satellite capturing method for a vehicle-mounted relay station, the receiving step of receiving a beacon signal transmitted from a communication satellite, and the beacon from the capturing target satellite based on the receiving frequency and the receiving level. A beacon signal determination step of determining a signal, an angle calculation step of calculating an azimuth angle and an elevation angle based on position information of an in-vehicle station and a satellite to be captured, and a first centered on the azimuth angle calculated by the angle calculation step. A lock-on step of driving the antenna within the angle range and locking on the beacon signal based on the determination result of the beacon signal determination step.

According to a fourth aspect of the present invention, there is provided a satellite acquisition method for a vehicle-mounted relay station, wherein a lock-on step locks on a beacon signal of a satellite to be acquired, and then a second angle narrower than a first angle range. It comprises a peak search step of driving the antenna within the range to search for an azimuth angle and an elevation angle at which the reception level becomes maximum.

[0012]

1 is a block diagram showing an example of the configuration of a satellite acquisition system for a vehicle-mounted relay station according to the present invention. In the figure, 1 is a satellite to be captured, 2 is an in-vehicle station antenna, 3
Is a power feeding device, 4 is a transmitting / receiving device, 5 is an antenna driving device,
6 is an antenna control device, 7 is a beacon reception determination device, 1
0 is an in-vehicle station for satellite communication.

The capture target satellite 1 is a communication satellite to be captured by the vehicle-mounted station 10, and transmits and receives communication signals.
An unmodulated wave having a known predetermined frequency is transmitted as a beacon signal. Here, the satellite 1 is a commercial geostationary satellite launched on the equator, and the frequency of the transmitted / received wave is 10
GHz or higher, for example, the transmitted wave is 14 GHz and the received wave is 12
It shall be GHz.

The on-vehicle station 10 is a relay station for mobile satellite communication, which comprises an on-vehicle station antenna 2, a power feeding device 3, a transmitting / receiving device 4, an antenna driving device 5, an antenna control device 6 and a beacon reception discriminating device 7. Transmission and reception with the communication satellite 1 are performed in a stationary state at the destination.

As the vehicle-mounted station antenna 2, a parabolic antenna having a high directivity is used for transmitting and receiving a high frequency of 10 GHz or more. The beam width of the parabolic antenna is narrower than that of a directional planar antenna (phased array antenna), and becomes smaller as the diameter increases. For example, when a parabolic antenna with a diameter of 1.4 m is used, the beam width of the antenna is as narrow as about 1 degree.

The power feeding device 3 is a waveguide for transmitting a transmission wave and a reception wave between the antenna 2 and the transmission / reception device 4. The transmission / reception device 4 performs transmission / reception processing such as modulation / demodulation of communication signals and frequency conversion.

The beacon reception discriminating device 7 measures the reception level by extracting the frequency component of the beacon signal of the satellite 1 to be captured from the reception signal of the antenna 2. During the search for lock-on of the beacon signal, it is determined whether the beacon signal is from the capture target satellite 1. That is, based on the reception frequency and the reception level, it is determined whether or not the beacon signal from the capture target satellite 1 is locked on, and the determination signal is output to the antenna control device 6. At the time of peak search after lock-on, the direction (azimuth angle and elevation angle) that maximizes the reception level is obtained.

The antenna control device 6 controls the elevation angle and azimuth angle of the vehicle-mounted station antenna 2 based on the position information of the satellite 1 to be captured and the vehicle-mounted station 10 input by the operator. Further, the elevation angle and the azimuth angle of the vehicle-mounted station antenna 2 are automatically controlled based on the determination signal of the beacon signal to capture the capture target satellite 1. The antenna driving device 5 drives the vehicle-mounted station antenna 2 by performing motor control or the like based on the control signal from the antenna control device 6.

Steps S100 to S107 of FIG. 2 are a flow chart showing an example of the satellite capturing method of the vehicle-mounted relay station according to the present invention. After the satellite communication vehicle-mounted station 10 arrives at the relay site, the antenna 2 is captured. The operation for automatically pointing the satellite 1 is shown.

First, the in-vehicle station operator inputs positional information such as the geographical position of the own station and the orbital position of the satellite 1 to be captured to the antenna control device 6 (step S101). For example, latitude and longitude data is input as the geographical position of the own station. If the satellite 1 to be captured is a geostationary satellite on the equator, since the altitude and latitude are constant, these data are preset and only the longitude data is input.
Further, the reception frequency of the beacon reception determination device 7 is set to the beacon frequency of the capture target satellite 1 (step S10).
2). The antenna control device 6 calculates the azimuth angle and the elevation angle of the antenna 2 with respect to the capture target satellite 1 based on the input position information (step S103).

Next, the in-vehicle station operator switches the antenna control device 6 to the satellite capture mode to start automatic satellite capture. That is, after that, satellite acquisition is performed without the intervention of the on-board station operator. First, the antenna driving device 5 sets the antenna 2 so that the elevation angle of the antenna 2 becomes the angle calculated by the antenna control device 6.
Is driven and fixed in the elevation direction (step S104).

On the other hand, as for the azimuth of the antenna 2, the beacon signal search is started within a predetermined angle range (2α degrees) centered on the angle calculated by the antenna control device 6 (S105). That is, the antenna control device 6 obtains an angle obtained by adding −α (or + α) to the calculated azimuth angle as the search start angle, and outputs it to the antenna drive device 5 as the antenna azimuth angle. afterwards,
The antenna control device 6 sequentially increases (or decreases) the azimuth angle.
Then, the azimuth angle at which the beacon signal is locked on is searched for.

At this time, the beacon reception discriminating device 7 extracts the frequency component of the beacon signal from the received wave of the antenna 2 and obtains its reception level. The antenna control device 6 compares the reception level of the locked-on beacon signal with a predetermined threshold value. As a result, if the reception level exceeds the threshold value, the search is stopped, while if it does not exceed the threshold value, the search is performed. Is continued (step S106).

When two or more communication satellites are transmitting beacon signals of the same frequency, the reception level of the beacon signal from the communication satellite other than the closest satellite to be captured becomes the reception level of the beacon signal from the satellite to be captured. Since it is significantly smaller than the above, the beacon signal from the acquisition target satellite can be identified by appropriately setting the threshold level.

If the beacon signal is locked on and the reception level exceeds a predetermined threshold value, fine adjustment is performed by peak search (step S107). That is, the elevation level and the azimuth angle are respectively changed in a minute angle range, and the beacon reception determination device 7 obtains the reception level, so that the reception level becomes maximum and
The elevation angle and the azimuth angle at which the capture target satellite 1 is located at the center of the beam are obtained. The peak search angle range is smaller than the search angle range (2α degrees) for lock-on.

FIG. 3 is a diagram showing an example of the movement of the beam of the antenna 2 of FIG. 1 at the time of automatic satellite acquisition.
Shows a search operation for lock-on, and (b) shows a peak search operation. D1 to D5 in the figure are beam directions (azimuth angles) of the antenna 2, 1 is a satellite to be captured, and 1'is a satellite not to be captured.

The beam azimuth D1 is an azimuth calculated from the position information of the satellite 1 to be captured and the vehicle-mounted station 10. The beam of the antenna 2 is driven from the azimuth D2 to D3 so that the angular range is 2α with the azimuth D1 as the center.
At this time, the beacon signal of the satellite 1'is received, but since the reception level does not exceed the threshold value, the search is continued and the direction D4
When the beacon signal of the satellite 1 whose reception level exceeds the threshold value is received at, the search is stopped. After that, the beam of the antenna 2 is driven so that the angular range is 2β centering on the azimuth D4, and the azimuth D5 having the maximum reception level is detected.

In this way, if the reception level of the locked-on beacon signal exceeds the threshold value, it is determined as the satellite to be captured, and further fine adjustment is performed by peak search to complete satellite capture. This automatic satellite acquisition (step S103
~ S107) takes 2 to 3 minutes, and satellite acquisition can be completed in a shorter time compared to the conventional manual operation. Further, since the beacon signal is searched based on the frequency and reception level of the beacon signal, satellites other than the satellite to be captured will not be erroneously captured.

[0029]

According to the satellite capturing system of the vehicle-mounted relay station and the satellite capturing method of the vehicle-mounted relay station according to the present invention, the antenna of the vehicle-mounted station can be directed to the satellite to be captured in a short time. Therefore, it is possible to realize an in-vehicle station that can start relaying in a short time after arriving at the relay site.

Further, according to the satellite capturing system of the vehicle-mounted relay station and the satellite capturing method of the vehicle-mounted relay station according to the present invention, it is possible to prevent the communication satellite which is not the capturing target from being captured by mistake and to reliably capture the capturing target satellite. can do. Further, since the communication satellite can be automatically captured, a skilled operator is not required, labor cost can be reduced, and operating cost can be reduced, and human error of the operator can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a satellite acquisition system for an on-vehicle relay station according to the present invention.

FIG. 2 is a flowchart showing an example of a satellite acquisition method for an onboard relay station according to the present invention.

FIG. 3 is a diagram showing an example of a beam movement of the antenna 2 of FIG. 1 during automatic satellite acquisition.

FIG. 4 is a block diagram showing a configuration of a conventional satellite acquisition system.

[Explanation of symbols]

1 satellite to be captured, 2 in-vehicle station antenna, 3 power feeding device, 4 transmitting / receiving device, 5 antenna driving device, 6 antenna control device, 7 beacon receiving device, 8 spectrum analyzer 10 satellite communication in-vehicle station, D1 to D5 beam azimuth

Claims (4)

[Claims] 1. An antenna for receiving a beacon signal transmitted from a communication satellite, a beacon reception discriminating device for discriminating a beacon signal from a capture target satellite based on a reception frequency and a reception level, an on-vehicle station and a capture target satellite. An antenna control device that calculates an azimuth angle and an elevation angle based on position information, and an antenna drive device that drives the antenna are provided, and the antenna is controlled within a first angle range centered on the azimuth angle calculated by the antenna control device. A satellite acquisition system for an on-vehicle relay station, which is automatically driven to lock on to a beacon signal based on a determination signal from a beacon reception determination device. 2. The peak search is performed by driving the antenna within a second angle range narrower than the first angle range after locking on the beacon signal of the satellite to be captured. The satellite acquisition system for the vehicle-mounted relay station described in. 3. A receiving step of receiving a beacon signal transmitted from a communication satellite, a beacon signal determining step of determining a beacon signal from a capture target satellite based on a reception frequency and a reception level, an in-vehicle station and a capture target satellite. The angle calculation step of calculating the azimuth angle and the elevation angle based on the position information of the antenna, the antenna is driven within the first angle range centered on the azimuth angle calculated by the angle calculation step, and the discrimination result by the beacon signal discrimination step Lock-on step of locking on to a beacon signal based on the above. 4. An azimuth angle at which the reception level becomes maximum by driving the antenna within a second angle range narrower than the first angle range after locking on the beacon signal of the satellite to be captured by the lock-on step. And a peak search step for searching an elevation angle, the satellite capturing method for a vehicle-mounted relay station according to claim 3, characterized in that: