JPH05206910A - Satellite acquisition system for satellite communication earth station - Google Patents

Abstract

PURPOSE:To accurately acquire a communication satellite in a simple addition circuit. CONSTITUTION:A control circuit 12 discriminates whether AGC voltage 10 which a receiver 6 generates exceeds prescribed voltage or not. An ID code is detected from a demodulation signal 8 which the receiver 5 outputs and it is discriminated whether the ID code coincides with a previously decided ID code or not. An antenna 1 is adjusted as follows. First, a reception frequency is set so that an SCPC carrier signal transmitted from the satellite can be received in the receiver 6. Then, the antenna 1 is adjusted and it is set to receive the signal in a regular level based on the discriminated result of AGC voltage 10 by the control circuit 12. Then, the discriminated result of the 1D code by the control circuit 12 is monitored. When the ID code detected by a demodulation signal 8 coincides with the previously decided ID code, it is judged that the direction of the antenna 1 is correctly set. When it does not coincide in evidence that the satellite different from the prescribed satellite is acquired, so adjustment is tried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for adjusting the direction of an antenna of a satellite communication earth station to acquire a satellite.

[0002]

2. Description of the Related Art SCPC (Single Channel Per Carrie)
FIG. 2 shows an example of a conventional satellite communication earth station for transmitting voice or data signals by the r) method. Transmission signal 9 is S
It is supplied to the feeder 2 through the CPC transmitter 4 and the high frequency amplifier 3, and then transmitted to the communication satellite through the antenna 1. On the other hand, the signal from the communication satellite is received by the antenna 1 and passed through the feeder 2 and the low noise amplifier 5 to S
The signal is input to the CPC receiver 6, and the receiver 6 outputs a carrier signal of the SCPC system, that is, a demodulated signal 8 of the SCPC carrier signal.

By the way, in order to perform satellite communication by such an earth station, it is necessary to orient the direction of the antenna 1 to a required satellite accurately. Therefore, in the past, the received signal was observed by the spectrum analyzer 7 and the direction of the antenna was adjusted.
Since the level of the SCPC carrier signal is lower than that of the TV signal and has a narrow band, the spectrum analyzer 7 is generally connected to the output of the amplifier 5 and has a relatively high level in the received signal.
Adjust the antenna by observing V signals.

Further, when the earth station is a portable station and lightweight is required and therefore the spectrum analyzer cannot be used, the meter circuit 11 is used instead of the spectrum analyzer as shown in FIG. Generated by receiving a carry signal for
The C voltage 10 is observed by the swing of the meter of the meter circuit 11, and the direction of the antenna is adjusted so that the reception level represented by the AGC voltage becomes maximum. The receiver 6 specifically generates an AGC voltage by a pilot signal that serves as a reference signal for frequency stabilization in the SCPC method.

[0005]

However, recently, a large number of communication satellites have been launched, and the distance between the satellites is narrowed to a few degrees in the azimuth direction. Therefore, in the case of a mobile station in which the spectrum analyzer cannot be used, it is difficult to correctly acquire satellites arranged in such a close proximity.

Particularly, when a plurality of satellites using the SCPC signal of the same frequency are arranged close to each other, there is a possibility that a portable station which can observe only the reception level may erroneously capture another satellite. high. For example, when an active satellite and a spare satellite are arranged, the transponder is often set to the same frequency, and the pilot signal is also set to the same frequency. Therefore, in such a case, it is extremely difficult to correctly acquire the required satellite.

An object of the present invention is to solve the above problems and to provide a satellite acquisition system for a satellite communication earth station which can correctly acquire a communication satellite by only adding a simple circuit.

[0008]

The present invention outputs a demodulated signal of an SCPC carrier signal and generates an AGC voltage in a system for acquiring the satellite by adjusting the direction of the antenna of a satellite communication earth station. By the receiver for SCPC and the AGC voltage generated by the receiver for SCPC,
Level discriminating means for discriminating a reception level, and the SCPC
The satellite communication earth station is provided with a code discriminating means for obtaining an ID code from the demodulated signal output from the receiver for radio and comparing the ID code with a predetermined ID code to discriminate whether or not they match. It is characterized by

[0009]

For example, even when a working satellite and a spare satellite are present and their transponders are set to the same frequency, the SCPC carrier signal is different between the working and the spare I.
It is modulated with the D code. Therefore, in the satellite communication earth station based on the satellite acquisition system of the present invention, the direction of the antenna can be adjusted correctly as follows. That is, first SC
The reception frequency is set to the frequency of the carry signal so that the PC receiver can receive the SCPC carrier signal transmitted from the satellite. Next, the antenna is adjusted so that the signal can be received at a normal level based on the result of the AGC voltage discrimination by the level discriminating means. After that, the result of ID code discrimination by the code discriminating means is monitored, and when the ID code detected from the demodulated signal matches a predetermined ID code, it is determined that the direction of the antenna is set correctly. On the other hand, if the ID codes do not match, it means that a satellite different from the required satellite has been captured, and the antenna adjustment is performed again.

Since the level discriminating means merely discriminates the voltage level and the code discriminating means merely discriminates the ID code, they can be easily realized by using, for example, a CPU. Therefore, according to the present invention, the communication satellite can be correctly captured only by adding a simple circuit.
The present invention is particularly effective for a portable station that needs to be lightweight.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows an example of a satellite communication earth station based on the satellite acquisition system of the present invention. The basic configuration of this earth station is the same as the earth station shown in FIGS. 2 and 3, and is provided with an antenna 1, a feeder 2, a high frequency amplifier 3, a transmitter 4 for SCPC, a low noise amplifier 5 and a receiver 6 for SCPC. ing.
Then, the transmission signal 9 is supplied to the feeder 2 through the SCPC transmitter 4 and the high frequency amplifier 3, and is transmitted to the communication satellite through the antenna 1. On the other hand, the signal from the communication satellite is received by the antenna 1, is input to the receiver 6 for the SCPC through the feeder 2 and the low noise amplifier 5, and the receiver 6 outputs the demodulated signal 8 of the SCPC carrier signal, and the reception level is changed. Generate a corresponding AGC voltage 10.

The earth station further includes a control circuit 12. The control circuit 12 has two functions. First, it is determined whether the AGC voltage 10 generated by the receiver 6 exceeds a predetermined voltage. The control circuit 12 also detects the ID code from the demodulated signal 8 output from the receiver 6 and determines whether or not it matches the predetermined ID code.

In this earth station, the antenna 1 is adjusted as follows. First, the reception frequency is set to the frequency of the carry signal so that the receiver 6 can receive the SCPC carrier signal sent from the satellite. Next, antenna 1
Is adjusted so that the control circuit 12 can receive the signal at a normal level based on the determination result of the AGC voltage 10. After that, the result of the ID code discrimination by the control circuit 12 is monitored, and if the ID code detected from the demodulated signal 8 matches the predetermined ID code, the direction of the antenna 1 is set correctly. to decide. On the other hand, if the ID codes do not match, it means that a satellite different from the required satellite is captured, and the antenna 1 is readjusted.

Since the control circuit 12 only judges the AGC voltage and the ID code, it can be easily realized by using a CPU or the like.

[0015]

In the satellite communication earth station based on the satellite acquisition system of the present invention, the direction of the antenna is adjusted as follows. That is, first, the reception frequency is set to the frequency of the carry signal so that the SCPC receiver can receive the SCPC carrier signal sent from the satellite. Next, the antenna is adjusted so that the signal can be received at a normal level based on the result of the AGC voltage discrimination by the level discriminating means. After that, the result of ID code discrimination by the code discriminating means is monitored, and when the ID code detected from the demodulated signal matches a predetermined ID code, it is determined that the direction of the antenna is set correctly. On the other hand, if the ID codes do not match, it means that a satellite different from the required satellite has been captured, and the antenna adjustment is performed again.

As described above, not only the AGC voltage level but also the ID code is referred to. Therefore, even when a plurality of satellites are arranged close to each other or even when the same frequency is used, communication is performed. The satellite can be captured correctly.

Since the level discriminating means merely discriminates the voltage level and the code discriminating means merely discriminates the ID code, they can be easily realized by using, for example, a CPU. Therefore, according to the present invention, the communication satellite can be correctly captured only by adding a simple circuit.
The present invention is particularly effective for a portable station that needs to be lightweight.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a satellite communication earth station based on a satellite acquisition system of the present invention.

FIG. 2 is a block diagram showing an example of a satellite communication earth station based on a conventional satellite acquisition system.

FIG. 3 is a block diagram showing another example of a satellite communication earth station based on a conventional satellite acquisition system.

[Explanation of symbols]

 1 Antenna 2 Feeder 3 High Frequency Amplifier 4 Transmitter for SCPC 5 Low Noise Amplifier 6 Receiver for SCPC 12 Control Circuit

Claims (1)

[Claims] 1. A system for adjusting a direction of an antenna of a satellite communication earth station to capture a satellite, wherein a demodulated signal of an SCPC carrier signal is output and AGC is performed.
A receiver for SCPC that generates a voltage, a level discriminating unit that discriminates a reception level by the AGC voltage generated by the receiver for SCPC, and an ID based on the demodulated signal output by the receiver for SCPC.
A satellite of the satellite communication earth station, characterized in that the satellite communication earth station is provided with code judging means for obtaining a code and comparing the ID code with a predetermined ID code to judge whether or not they match. Capture method.