JP3732151B2 - Satellite capture system for in-vehicle relay station and satellite capture method for in-vehicle relay station - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a satellite acquisition system for an in-vehicle relay station and a satellite acquisition method for the in-vehicle relay station, and more particularly to a satellite acquisition system and method for automatically pointing an antenna of an in-vehicle station for satellite communication to a capture target satellite. .
[0002]
[Prior art]
FIG. 4 is a block diagram showing the configuration of a conventional satellite acquisition system, showing an in-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 transmission / reception device, 5 is an antenna driving device, 6 is an antenna control device, 8 is a spectrum analyzer, and 10 is an in-vehicle station for satellite communication. .
[0003]
After arriving at the relay site, the in-vehicle station 10 must first direct the in-vehicle station antenna 2 to the communication satellite 1 (capture target satellite) to be captured. Therefore, the in-vehicle station operator inputs the position information of the capture target satellite 1 and the in-vehicle station 10 to the antenna control device 6. The antenna control device 6 calculates the azimuth angle and elevation angle of the in-vehicle 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 in-vehicle station antenna 2 based on the calculated azimuth angle and elevation angle, and directs the in-vehicle station antenna 2 toward the capture target satellite 1.
[0004]
However, the communication satellite 1 is constantly moving slightly. When transmitting and receiving a signal of 10 GHz or higher, a parabolic antenna with high directivity is used as the in-vehicle station antenna 2, but its reception beam width (half-value width) is about 1 degree or less and is very narrow. Furthermore, the detection accuracy of the angle detection mechanism of the antenna 2 is limited. Therefore, even if the above-described antenna control method is used, it is impossible to accurately drive and control the in-vehicle station antenna 2 so that the capture target satellite 1 is at the true center position of the beam of the in-vehicle station antenna 2. Met.
[0005]
For this reason, the conventional in-vehicle station operator finally monitors the received carrier from the acquisition target satellite 1 using the spectrum analyzer 8, and manually sets the azimuth angle and elevation angle of the antenna 2 so that the reception level becomes maximum. Were fine-tuned to point to the beam center position of the capture target satellite 1.
[0006]
[Problems to be solved by the invention]
In the conventional satellite acquisition system, as described above, when the in-vehicle station antenna is directed to the acquisition target satellite, the in-vehicle station operator finally finely adjusts the in-vehicle station antenna manually. For this reason, it takes a considerable time (for example, about 15 minutes) from the arrival of the in-vehicle station to the start of the relay. In addition, simply observing the received carrier from the communication satellite with a spectrum analyzer cannot determine whether the capture target satellite is actually captured, and may cause an operational error of erroneously capturing a satellite that is not captured. It was. Therefore, a highly skilled operator was required for satellite acquisition.
[0007]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a satellite capturing system and a satellite capturing method capable of directing an in-vehicle station antenna to a capture target satellite in a short time. And It is another object of the present invention to provide a satellite acquisition system and a satellite acquisition method that do not erroneously acquire satellites that are not to be acquired. It is another object of the present invention to provide a satellite acquisition system and a satellite acquisition method capable of automatically directing an in-vehicle station antenna to an acquisition target satellite.
[0008]
[Means for Solving the Problems]
The satellite acquisition system of the in-vehicle relay station according to the first aspect of the present invention determines an beacon signal from a capture target satellite based on an antenna that receives a beacon signal transmitted from a communication satellite and a reception frequency and reception level. An azimuth angle calculated by the antenna control device, comprising: a beacon reception determination device; 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 the antenna. The satellite is driven within a first angle range centered on the beacon and is locked on the beacon signal based on the determination signal from the beacon reception determination device, thereby automatically capturing the capture target satellite.
[0009]
The satellite acquisition system of the in-vehicle relay station according to the second aspect of the present invention locks on the beacon signal of the acquisition target satellite and then drives the antenna within a second angular range narrower than the first angular range. Configured to perform a peak search.
[0010]
According to a third aspect of the present invention, there is provided a satellite acquisition method for an in-vehicle relay station according to the present invention, wherein a reception step of receiving a beacon signal transmitted from a communication satellite and a beacon signal from a capture target satellite are determined based on a reception frequency and a reception level A beacon signal determination step, an angle calculation step for calculating an azimuth angle and an elevation angle based on the position information of the in-vehicle station and the capture target satellite, and a first angle range centered on the azimuth angle calculated by the angle calculation step And a lock-on step for driving on the beacon signal based on the determination result in the beacon signal determination step.
[0011]
According to a fourth aspect of the present invention, there is provided a satellite acquisition method for an in-vehicle relay station according to the present invention, wherein the lock-on step locks on the beacon signal of the acquisition target satellite, and then within a second angle range narrower than the first angle range. A peak search step for searching for an azimuth angle and an elevation angle at which the reception level is maximized by driving the antenna is configured.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a configuration example of a satellite acquisition system for an in-vehicle 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, and 10 is a vehicle for satellite communication Station.
[0013]
The capture target satellite 1 is a communication satellite to be captured by the in-vehicle station 10 and transmits / receives a communication signal and transmits a non-modulated wave having a known predetermined frequency as a beacon signal. Here, it is assumed that the satellite 1 is a commercial geostationary satellite launched on the equator, and the frequency of the transmission / reception wave is 10 GHz or more, for example, the transmission wave is 14 GHz and the reception wave is 12 GHz.
[0014]
The in-vehicle station 10 is a mobile satellite communication relay station including the in-vehicle station antenna 2, the power feeding device 3, the transmission / reception device 4, the antenna driving device 5, the antenna control device 6, and the beacon reception determination device 7. Transmission / reception with the communication satellite 1 is performed in a stationary state.
[0015]
A parabolic antenna with high directivity is used for the in-vehicle station antenna 2 in order to perform transmission and reception at 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 decreases as the diameter increases. For example, when a parabolic antenna having a diameter of 1.4 m is used, the beam width of the antenna is as narrow as about 1 degree.
[0016]
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.
[0017]
The beacon reception determination device 7 extracts the frequency component of the beacon signal of the capture target satellite 1 from the reception signal of the antenna 2 and measures the reception level. At the time of searching for lock-on of the beacon signal, it is determined whether or not the beacon signal is from the acquisition 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. In the peak search after lock-on, the direction (azimuth angle and elevation angle) in which the reception level is maximum is obtained.
[0018]
The antenna control device 6 controls the elevation angle and the azimuth angle of the in-vehicle station antenna 2 based on the position information of the capture target satellite 1 and the in-vehicle station 10 input by the operator. Further, the satellite 1 is captured by automatically controlling the elevation angle and azimuth angle of the in-vehicle station antenna 2 based on the determination signal of the beacon signal. The antenna driving device 5 performs motor control or the like based on a control signal from the antenna control device 6 to drive the in-vehicle station antenna 2.
[0019]
Steps S100 to S107 in FIG. 2 are flowcharts showing an example of the satellite capturing method of the in-vehicle relay station according to the present invention. After the satellite communication in-vehicle station 10 arrives at the relay site, the antenna 2 is set as the capturing target satellite 1. An operation for automatically pointing is shown.
[0020]
First, the in-vehicle station operator inputs position information such as the geographical position of the own station and the orbit position of the capture target satellite 1 to the antenna control device 6 (step S101). For example, latitude and longitude data are input as the geographical position of the local station. Further, if the capture target satellite 1 is a geostationary satellite on the equator, the altitude and latitude are constant, so these data are set in advance, and only 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 S102). The antenna control device 6 calculates the azimuth angle and elevation angle of the antenna 2 with respect to the capture target satellite 1 based on the input position information (step S103).
[0021]
Next, the in-vehicle station operator switches the antenna control device 6 to the satellite acquisition mode, whereby automatic satellite acquisition is started. That is, after that, satellite acquisition is performed without the intervention of the in-vehicle station operator. First, the antenna driving device 5 drives and fixes the antenna 2 in the elevation angle direction so that the elevation angle of the antenna 2 becomes the angle calculated by the antenna control device 6 (step S104).
[0022]
On the other hand, the azimuth angle of the antenna 2 starts searching for a beacon signal 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. Thereafter, the antenna control device 6 sequentially increases (or decreases) the azimuth angle, and searches for the azimuth angle that locks on the beacon signal.
[0023]
At this time, the beacon reception determination device 7 extracts the frequency component of the beacon signal from the received wave of the antenna 2 and obtains the 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. Is continued (step S106).
[0024]
When two or more communication satellites are transmitting beacon signals of the same frequency, the reception level of beacon signals from communication satellites other than the nearest capture target satellite is compared to the reception level of beacon signals from the capture target satellite. Since it becomes remarkably small, a beacon signal from a capture target satellite can be identified by appropriately setting the threshold level.
[0025]
If the beacon signal is locked on and the reception level exceeds a predetermined threshold, fine adjustment is performed by peak search (step S107). In other words, the elevation angle and the azimuth angle are changed in a minute angle range, and the beacon reception determination device 7 obtains the reception level, whereby the reception level is maximized and the elevation angle at which the capture target satellite 1 is located at the center of the beam of the antenna 2. And azimuth. The peak search angle range is smaller than the search angle range (2α degrees) for lock-on.
[0026]
FIGS. 3A and 3B are diagrams showing an example of the beam movement of the antenna 2 in FIG. 1 at the time of capturing an automatic satellite. FIG. 3A shows a search operation for lock-on, and FIG. 3B shows a peak search operation. D1 to D5 in the figure are the beam direction (azimuth angle) of the antenna 2, 1 is a satellite to be captured, and 1 'is a satellite that is not to be captured.
[0027]
The beam azimuth D1 is an azimuth angle calculated from position information of the capture target satellite 1 and the in-vehicle station 10. The beam of the antenna 2 is driven from the direction D2 to D3 so that the angle range is 2α with the direction D1 as the center. At this time, the beacon signal of the satellite 1 ′ is received, but the search is continued because the reception level does not exceed the threshold value, and the search is stopped when the beacon signal of the satellite 1 whose reception level exceeds the threshold value in the direction D4 is received. Thereafter, the beam of the antenna 2 is driven so that the angle range is 2β with the azimuth D4 as the center, and the azimuth D5 having the maximum reception level is detected.
[0028]
In this way, if the reception level of the locked-on beacon signal exceeds the threshold value, it is determined that the satellite is a capture target satellite, and further fine adjustment is performed by peak search, thereby completing satellite capture. The time required for this automatic satellite capture (steps S103 to S107) is 2 to 3 minutes, and the satellite capture can be completed in a shorter time compared to the conventional manual capture. In addition, since the beacon signal is searched based on the frequency and reception level of the beacon signal, satellites other than the capture target satellite are not erroneously captured.
[0029]
【The invention's effect】
According to the satellite acquisition system of the in-vehicle relay station and the satellite acquisition method of the in-vehicle relay station according to the present invention, the in-vehicle station antenna can be directed to the acquisition target satellite in a short time. For this reason, it is possible to realize an in-vehicle station that can start relaying in a short time after arrival at the relay site.
[0030]
In addition, according to the satellite capture system of the in-vehicle relay station and the satellite capture method of the in-vehicle relay station according to the present invention, it is possible to prevent erroneous capture of communication satellites that are not captured, and reliably capture the capture target satellite. it can. Further, since the communication satellite can be automatically acquired, a skilled operator is not required, the operation cost can be reduced by reducing the labor cost, and the human error of the operator can be prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of a satellite acquisition system for an in-vehicle relay station according to the present invention.
FIG. 2 is a flowchart illustrating an example of a satellite acquisition method for an in-vehicle relay station according to the present invention.
FIG. 3 is a diagram showing an example of 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 Car station antenna, 3 Feeder, 4 Transmitter / receiver,
5 antenna driving device, 6 antenna control device, 7 beacon receiving device,
8 Spectrum Analyzer 10 Satellite Communication Vehicle Station, D1-D5 Beam Direction

Claims (4)

Based on the antenna that receives the beacon signal transmitted from the communication satellite, the beacon reception determination device that determines the beacon signal from the capture target satellite based on the reception frequency and the reception level, and the position information of the in-vehicle station and the capture target satellite An antenna control device that calculates an azimuth angle and an elevation angle and an antenna drive device that drives the antenna are provided, the antenna is driven within a first angle range centered on the azimuth angle calculated by the antenna control device, and a beacon is received. A satellite capture system for an in-vehicle relay station, wherein a capture target satellite is automatically captured by locking on a beacon signal based on a determination signal from a determination device. 2. The in-vehicle relay according to claim 1, wherein after the lock-on to the beacon signal of the acquisition target satellite, the peak search is performed by driving the antenna within a second angle range narrower than the first angle range. Station satellite acquisition system. Based on a reception step of receiving a beacon signal transmitted from a communication satellite, a beacon signal determination step of determining a beacon signal from a capture target satellite based on the reception frequency and reception level, and position information of the in-vehicle station and the capture target satellite An angle calculation step for calculating an azimuth angle and an elevation angle, and driving an antenna within a first angle range centered on the azimuth angle calculated by the angle calculation step, and a beacon signal based on the determination result in the beacon signal determination step And an on-vehicle relay station satellite capturing method, comprising: After locking on the beacon signal of the acquisition target satellite by the lock-on step, the antenna is driven within the second angle range narrower than the first angle range to search for the azimuth angle and elevation angle at which the reception level is maximum. 4. The satellite acquisition method for an in-vehicle relay station according to claim 3, further comprising a peak search step.

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