JPH0728254B2 - Satellite line monitoring system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a system for monitoring the line status of a satellite line in a satellite communication earth station that communicates via a satellite, and in particular to the effective isotropic radiated power of the satellite output. The present invention relates to a monitoring method in a satellite communication earth station that does not have a constant function.

[Conventional technology]

In satellite communication, attenuation of radio waves due to rainfall or the like generally affects the line condition. For this reason, in satellite communication using high frequency bands such as the quasi-millimeter wave band, as a countermeasure, the transmission power from the satellite communication earth station is controlled according to the rainfall attenuation of the uplink from the satellite communication earth station to the satellite. Measures are taken to provide a function (transmission power control function) that keeps the output isotropic radiated power constant.

However, in satellite communication using a frequency band lower than the quasi-millimeter wave band, it is common that the transmission power control function is not provided because the influence of rain attenuation on the line condition is within an allowable range.

[Problems to be Solved by the Invention]

As described above, when performing satellite communication between satellite communication earth stations that have a transmission power control function, the effective isotropic radiated power of the satellite output is constant, so it is the satellites that affect the line status It can be thought of as rain attenuation on the downlink to the communications earth station. Therefore, even if an error occurs in the signal communicated using the satellite line, by checking the weather condition of the satellite earth station on the receiving side, the cause of the error may be the line condition or the satellite communication device. You can judge whether it is a thing.

However, when satellite communication is performed between satellite communication earth stations that do not have a transmission power control function, the line condition is affected by the rain attenuation of the uplink from the satellite earth station to the satellite and from the satellite to the satellite. It must be considered as either or both due to downlink rain attenuation towards the communication earth station. Therefore, when an error occurs in the signal communicated using the satellite line,
It is necessary to check the weather conditions of the satellite communication earth stations on both the transmitting side and the receiving side to determine whether the cause of the error is the line condition or the satellite communication device.

However, it is not easy to check the weather condition of both satellite communication earth stations because the satellite communication earth stations are usually located at very distant positions. In particular, if the satellite earth station is unattended and an error occurs, the weather condition cannot be understood, and it is very difficult to find the cause.

It is an object of the present invention to provide a monitoring system capable of monitoring the line status of a satellite line of a communication partner station and its own station even in a satellite communication earth station that does not have a function of making effective isotropic radiated power constant.

[Means for Solving the Problems]

According to the monitoring system of the present invention, a transmitting means for transmitting the same signal as the communication signal transmitted by the communication partner station is provided to the satellite communication earth station which does not have the function of making the effective isotropic radiated power of the satellite output constant. And a logical means for estimating the uplink line condition of the satellite earth station of the other party based on the transmission output levels of the other station and the own station.

[Action]

In this configuration, the logic means receives the communication signal transmitted by the own station, and calculates the amount of downlink attenuation from the satellite to the own station from the received level. Then, the communication signal transmitted from the partner station is received, the uplink attenuation amount of the partner station is calculated from the reception level and the downlink attenuation amount of the own station, and the communication partner station and the own station are calculated based on this. It becomes possible to monitor the line status of the satellite line.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a satellite communication earth station of the present invention. FIG. 2 shows an example of a configuration of satellite communication for communicating via a satellite. That is, here, as shown in FIG. 2, an example in which the satellite communication earth stations 2 and 3 are communicating via the satellite 1 is shown, and each earth station 2 and 3 has the configuration shown in FIG. .

In the satellite communication earth station 2, the communication signal 102 from the satellite communication earth station 3 is received by the antenna 11, demodulated by the demodulator 14 through the low noise amplifier 12 and the reception frequency converter 13, and used as a reception signal. Further, the demodulator 14 performs automatic gain control (AGC) according to the reception level detected by the reception level detector 15. Further, the detected reception level is sent to the logic unit 17.

On the other hand, if there is an error in the received signal from the demodulator 14, the error detector 16 sends the information to the logic unit 17. The logic unit 17 normally controls the modulator 18 so as to transmit a communication signal from the satellite communication earth station 3 to the satellite communication earth station 2, but error information is sent from the error detector 16, etc. Depending on the conditions, the modulator 18 is controlled to transmit the same signal as the received signal transmitted from the satellite communication earth station 3, and the intermediate frequency amplifier 19,
The signal is output from the antenna 11 through the transmission frequency converter 20 and the transmission power amplifier 21, returned by the satellite 1, and received by the local station.
The reception level at this time is detected by the reception level detector 15 and sent to the logic unit 17.

Generally, since the antenna output level of the satellite communication earth station is required to have high stability, it is possible to calculate the attenuation amount of the uplink and downlink from the attenuation amount of the reception level with respect to the output level of the own station. The relationship between the uplink and downlink attenuation amounts is known in "Technical examination standards for radio stations that perform fixed satellite service using satellite communication" and the like. With this reference, the logic unit 17 can know the downlink attenuation amount of the own station. Therefore, from the reception signal level of the reception signal 102 from the other satellite earth station 3 and the downlink attenuation amount of the own station, the other station The uplink attenuation of can be estimated.

It should be noted that it is sufficient for the satellite return signal 101 to be transmitted and received at intervals that do not affect normal communication, and it is clear that another frequency considered to be an error range of the reception level may be used.

In this way, by estimating the downlink attenuation of the local station and the uplink attenuation of the remote station, the satellite communication status can be monitored, and even if an error occurs in the received signal, the cause It becomes easy to find out.

〔The invention's effect〕

As described above, the present invention is based on the transmitting means for transmitting the same signal as the communication signal transmitted by the communication partner station, and the uplink of the partner satellite earth station based on the transmission output level of the communication partner station and its own station. Since it is equipped with a logical means for estimating the line state of the satellite communication line, the line state of the satellite line of the communication partner station and its own station is also available in the satellite communication earth station which does not have the function of keeping the effective isotropic radiated power of the satellite output constant. It is possible to obtain the effect of facilitating the operation and maintenance of the satellite line because it is possible to monitor.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a satellite communication earth station of the present invention, and FIG. 2 is a diagram showing a configuration of satellite communication. 1 ... Satellite, 2 ... Satellite communication earth station (own station), 3 ... Satellite communication earth station (other station), 11 ... Antenna, 12 ... Low noise amplifier, 13 ... Reception frequency converter, 14 ...... Demodulator, 15
...... Reception level detector, 16 …… Error detector, 17 …… Logic device, 18 …… Modulator, 19 …… Intermediate frequency amplifier, 20 …… Transmission frequency converter, 21 …… Transmission power amplifier, 101 ・ ・ ・… Own station return signal, 102 …… Received signal from partner station.

Claims (2)

[Claims] 1. In a satellite communication earth station that performs communication via a satellite, receiving means for receiving a communication signal transmitted from a communication partner station, and reception level detecting means for detecting a reception level of the communication signal. Error detecting means for detecting an error in the communication signal, transmitting means for transmitting the same signal as the communication signal transmitted by the communication partner station, and recognition of the transmission output levels of the communication partner station and the own station A logical means for estimating the state of the uplink satellite channel going from the satellite earth station to the satellite, and calculating the uplink attenuation of the partner station by this logical means and detecting an error in the communication signal. And satellite line monitoring method. 2. The logic means receives a communication signal transmitted from its own station, calculates a downlink attenuation amount from a satellite to its own station based on the reception level, and outputs a communication signal transmitted from the other station. 2. The satellite line monitoring method according to claim 1, wherein the reception level is received, and the uplink attenuation amount of the partner station is calculated from the reception level and the downlink attenuation amount of the own station.