JP4804849B2 - Communication satellite and communication system - Google Patents

Description

  The present invention relates to a communication satellite. In particular, the present invention relates to an antenna used for communication between communication satellites.

In geostationary satellites (communication satellites) used for communication / broadcasting or the like, the direction (antenna beam) directed by the ground antenna is unique to each antenna. Assuming that the area on the earth where the antenna beam hits is the coverage, the geostationary satellite communicates / broadcasts with a ground station in a coverage area (attached) within the coverage, a gateway station, or the like.
Thereby, it is possible to communicate with each other between a ground station in a service area within a coverage, a gateway station, or the like via a geostationary satellite.
When one geostationary satellite has two or more coverages (for example, one ground antenna has one or more antenna beams, multiple ground antennas, etc.), the service area between different coverages Can also communicate with each other between the ground stations and gateway stations (conventional example 1).

In addition, there is an example in which a geostationary satellite has a function of relaying acquired data of a low orbiting satellite from a geostationary relay satellite to a ground station (conventional example 2).
JP 2004-120616 A

In Conventional Example 1, when one geostationary satellite has two or more coverages, communication between different coverages is possible, but communication between the coverages of different geostationary satellites is not possible. There is a problem.
Since the inter-satellite communication system of Conventional Example 2 is an intercommunication between a geosynchronous orbit and a low orbit satellite, the relative positional relationship constantly changes. For this reason, since the geostationary relay satellite needs a tracking function at a large angle, there is a problem that the cost is increased, the scale is increased, the system is complicated, and the mass and power consumption of the satellite are increased.

The communication satellite according to the present invention is:
In communication satellites that communicate with both ground stations and geostationary satellites that communicate with ground stations,
The main body of the communication satellite,
A plurality of antennas each directed in a predetermined direction fixed to the main body of the communication satellite;
A ground communication unit that communicates with the ground station via at least one of the plurality of antennas;
An anti-satellite communication unit that communicates with the geostationary satellite via at least one other antenna of the plurality of antennas;
A relay unit that relays communication between the ground communication unit and the satellite communication unit;
It is characterized by having.

The communication satellite according to the present invention includes, for example, a ground communication unit that communicates with a ground station and an anti-satellite communication unit that communicates with a geostationary satellite that communicates with the ground station, and thus communicates with the ground station and the ground station. Communication with geostationary satellites can be relayed. The geostationary satellite further relays the communication to the ground station with which the geostationary satellite communicates, thereby achieving an effect that communication / broadcasting between ground stations in an area where the geostationary satellite cannot directly communicate becomes possible.
Further, by operating the communication satellite according to the present invention on a geostationary orbit, the positional relationship between the ground station and the geostationary satellite with which the communication satellite communicates does not change. The pointing direction may be fixed. Therefore, it is not necessary to provide an antenna driving device or a tracking function, and the number of parts and the weight can be reduced, so that the manufacturing cost and the launch cost can be reduced.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

FIG. 1 is a block configuration diagram showing an example of a block configuration of a communication satellite 100 in this embodiment.
The communication satellite 100 includes ground antennas 111 and 112, an inter-stationary satellite antenna 113, an input switch matrix 120, a receiver group 130, a repeater group 140, an output switch matrix 150, a diplexer 163, an antenna adjustment mechanism 173 (an example of a direction adjustment unit) ).

The ground antennas 111 and 112 and the geostationary-satellite antenna 113 are examples of antennas, and have strong directivity in a predetermined direction.
The ground antennas 111 and 112 and the geostationary-satellite antenna 113 are fixed to the satellite body so that the pointing direction becomes a desired direction when the satellite is operated at a predetermined position on the geostationary orbit.

  The diplexer 163 separates the input signal according to the frequency band. Here, the signal from the geostationary inter-satellite antenna 113 is separated into a transmission frequency signal and a reception frequency signal, thereby separating the transmission signal and the reception signal.

  The input switch matrix 120 is a set of many switches. The input switch matrix 120 distributes and inputs the signals input from the ground antennas 111 and 112 and the diplexer 163 to any receiver in the receiver group 130. Thereby, for example, even when some receivers in the receiver group 130 fail, the function of the communication satellite 100 as a whole is maintained by distributing signals to other receivers.

  The receiver group 130 is a set of many receivers. The receiver converts the frequency and encoding method of the signal input from the input switch matrix 120 and outputs the converted signal.

  The repeater group 140 is a set of many repeaters. The repeater amplifies and outputs the signal input from the receiver.

  The output switch matrix 150 is a set of many switches. The output switch matrix 150 distributes and inputs the signals input from the repeaters to the ground antennas 111 and 112 or the diplexer 163.

Thereby, the receivers constituting the receiver group 130 function as a ground communication unit when the signals from the ground antennas 111 and 112 are input by the input switch matrix 120 and the signals from the diplexer 163 are input. Functions as a satellite communication unit.
The repeaters constituting the repeater group 140 function as a ground communication unit when outputting signals to the ground antennas 111 and 112 by the output switch matrix 150, and when outputting signals to the diplexer 163, Functions as a satellite communication unit.
The input switch matrix 120 and the output switch matrix 150 function as a relay unit by selecting receivers and repeaters and connecting the ground antennas 111 and 112 and the geostationary satellite antenna 113 as a whole. .

  The antenna adjustment mechanism 173 finely adjusts the direction of the geostationary satellite antenna 113. For example, the direction of the geostationary satellite antenna 113 is adjusted by a motor drive circuit. Further, the antenna adjustment mechanism 173 may adjust only one axis or may adjust two axes.

  A dedicated input port may be provided between the diplexer 163 and the input switch matrix 120. Further, an output dedicated port may be provided between the diplexer 163 and the output switch matrix 150.

  FIG. 2 is a diagram illustrating an example of an operation when two communication satellites 100 according to this embodiment are launched on a geostationary orbit and used as geostationary satellites 100a and 100b.

The ground antenna 111 of the geostationary satellite 100a is fixed in a direction pointing a predetermined range (coverage 201) on the ground with respect to the satellite body. For example, an uplink station 211 (an example of a ground station) in the coverage 201 ) Is received and transmitted to the downlink station 221 (an example of a ground station).
Similarly, the ground antenna 112 of the geostationary satellite 100a is fixed in a direction toward the coverage 202.
Further, the geostationary satellite antenna 113 of the geostationary satellite 100a is fixed in a direction toward the geostationary satellite 100b.

  The geostationary satellite 100b is fixed in a direction in which the ground antenna 111 is directed toward the coverage 203, and is fixed in a direction in which the ground antenna 112 is directed toward the coverage 204. The geostationary satellite antenna 113 is fixed in a direction pointing to the geostationary satellite 100a.

  Thereby, the geostationary satellite 100a and the geostationary satellite 100b can communicate via the geostationary satellite antenna 113.

Here, since the ground antennas 111 and 112 are fixed to the main bodies of the geostationary satellites 100a and 100b, the directivity directions of the ground antennas 111 and 112 vary depending on the directions of the geostationary satellites 100a and 100b.
The geostationary satellites 100a and 100b are equipped with an attitude control device (not shown), and the attitude control device keeps the directions of the geostationary satellites 100a and 100b constant. As a result, the ground antennas 111 and 112 face in the direction in which the respective coverages 201 to 204 are directed.

The geostationary satellite antenna 113 is basically fixed to the main bodies of the geostationary satellites 100a and 100b. Geostationary satellites are located on the same geostationary orbit, and their positional relationship does not change, so they are always in the same direction as long as they maintain a constant orientation with respect to the earth.
Therefore, if the orientation of the geostationary satellites 100a and 100b is kept constant by the attitude control device, even if the orientation of the geostationary satellite 100 is fixed with respect to the main bodies of the geostationary satellites 100a and 100b, The other party can be captured in the directivity direction and can communicate with each other.

For example, an uplink station 212 in coverage 202 transmits a signal.
In the geostationary satellite 100 a, the ground antenna 112 receives this signal, and the geostationary intersatellite antenna 113 passes through the receiver 132 (an example of the ground communication unit), the repeater 142 (an example of the satellite communication unit), and the diplexer 163. Send.
In the geostationary satellite 100b, the geostationary satellite-to-satellite antenna 113 receives this signal, and the ground antenna 112 passes through the diplexer 163, the receiver 134 (an example of the satellite communication unit), and the repeater 144 (an example of the ground communication unit). Send.
A downlink station 224 in coverage 204 receives this signal.
Accordingly, communication from the uplink station 212 to the downlink station 224 can be performed.

  Similarly, the signal transmitted by the uplink station 213 in the coverage 203 reaches the downlink station 222 in the coverage 202 via the geostationary satellite 100b and the geostationary satellite 100a.

FIG. 3 is a diagram showing an example of the positional relationship between the geostationary satellites 100a and 100b and the earth 200 in this embodiment.
The geostationary satellites 100a and 100b are arranged and operated on a geostationary orbit 300 whose revolution period coincides with the rotation period of the earth 200. Therefore, when viewed from above the earth 200, it appears to be stationary at one point in the air.
In addition, since the geostationary satellites 100a and 100b rotate in the same direction in the same cycle on the same orbit, the positional relationship between the earth 200 and the geostationary satellites 100a and 100b is always constant and does not change.

In FIG. 3, the geostationary satellite 100 a has a ground antenna 111 communicating with a ground station in the coverage 201 and a ground antenna 112 communicating with a ground station in the coverage 202. A geostationary satellite ground antenna is usually designed to preliminarily determine a region to communicate with and optimally match it, so it is difficult to point the ground antennas 111 and 112 to other regions and communicate with other coverage. It is.
Further, the geostationary satellite 100a is not visible from the coverages 203 and 204, or even if it can be seen, the direction is close to the horizon, so that the ground antennas 111 and 112 of the geostationary satellite 100a are directed to the coverages 203 and 204. However, it is difficult to directly communicate with the geostationary satellite 100a.

  According to this embodiment, it is possible to communicate between the coverages 201 and 202 and the coverages 203 and 204 via two geostationary satellites.

  FIG. 4 is a diagram illustrating an example of the coverages 201 to 204 of the geostationary satellites 100a and 100b in this embodiment.

  In FIG. 4, the geostationary satellite 100 a is a satellite whose main service area is an area centered in Europe, and communicates with ground stations in the coverages 201 and 202. The geostationary satellite 100b is a satellite whose main service area is an area centered on East Asia and Southeast Asia, and communicates with ground stations in the coverages 203 and 204.

  A geostationary satellite is normally launched on a geostationary orbit closest to the main service area. For example, the geostationary satellite 100a is located above Africa and the geostationary satellite 100b is located above Indonesia.

  Conventionally, when it becomes necessary to communicate via the geostationary satellite between the coverage 201 and the coverage 204 due to fluctuations in demand, for example, a new geostationary satellite is located at a position where both can be seen (for example, over the Indian Ocean). Need to be launched.

  According to this embodiment, since it is not necessary to launch a new satellite, the cost can be greatly reduced.

FIG. 5 is a diagram showing an example of a communication service supplied by this embodiment.
Within the coverage 201, there are service areas 231a to 231c and a gateway station 241 (an example of a base station and a ground station).
Similarly, within the coverage 202, there are service areas 232a and 232b and a gateway station 242. Within the coverage 203, there are service areas 233a to 233d. Within the coverage 204, there are service areas 234a and 234b and gateway stations 244a and 244b.
The gateway stations 241 to 244b are connected to, for example, a terrestrial communication network and connect communication with the terrestrial communication network to the geostationary satellites 100a and 100b.
In the service areas 231a to 234b, for example, there are satellite mobile phones and satellite broadcast receivers, which communicate with the geostationary satellites 100a and 100b and receive broadcasts from the geostationary satellites 100a and 100b.
Note that a gateway station, a satellite mobile phone in a service area, and the like are examples of communication apparatuses that communicate with the geostationary satellites 100a and 100b within the coverages 201 to 204. The coverages 201 to 204 may not include a gateway station like the coverage 203 or may include a plurality of gateway stations like the coverage 204 according to the contents of the service provided by each.

  According to this embodiment, by exchanging communication between the geostationary satellite 100a and the geostationary satellite 100b, communication between arbitrary ground stations in the coverage 201 to 204, reception of satellite broadcasts for other regions, etc. Is possible.

FIG. 6 is a conceptual diagram showing an example of communication between coverages enabled by this embodiment.
Conventionally, for example, a ground station in the coverage 201 can communicate with a ground station in the same coverage 201 or a ground station in the coverage 202 that is the coverage of the same geostationary satellite 100a. The ground station in the coverage 203 can communicate with a ground station in the same coverage 203 or a ground station in the coverage 204 that is the coverage of the same geostationary satellite 100b.
According to this embodiment, for example, communication between the ground station in the coverage 201 that is the coverage of the geostationary satellite 100a and the coverage 203 that is the coverage of the geostationary satellite 100b is also performed through the relay line of the geostationary satellite communication. Can be connected.
That is, the coverages 201 to 204 can be freely connected as if they were the coverage of one geostationary satellite.

FIG. 7 is a diagram illustrating an example of a time-series change in the direction of the geostationary satellite 100b as seen from the geostationary satellite 100a in this embodiment.
As described above, since the positional relationship between the geostationary satellite 100a and the geostationary satellite 100b is constant and does not change, the direction of the geostationary satellite 100b viewed from the geostationary satellite 100a should not change.
However, in reality, the direction of the geostationary satellite 100b may change due to factors such as attitude control errors. This change is considered to be a minute change within 0.1 degree at most.

Therefore, in this embodiment, the antenna 113 between the geostationary satellites is provided with an antenna adjustment mechanism 173 (an example of a direction adjustment unit).
The antenna adjustment mechanism 173 adjusts the direction of the geostationary-satellite antenna 113, but the range is minute within a maximum of 0.1 degree.

  FIG. 8 is a diagram illustrating an example of a time-series change in the direction of the low orbiting satellite as seen from the geostationary satellite.

As described above, when communicating between geostationary satellites, the change in the direction of the communication partner is extremely small compared to the case of communicating with the low orbiting satellite.
Therefore, there is no need for a large antenna driving device as in the case of communicating with a low orbiting satellite.

  Thus, even if the antenna adjustment mechanism 173 is provided, the manufacturing cost of the communication satellite 100 can be suppressed.

  Further, if the antenna adjustment mechanism 173 adjusts the direction of the geostationary satellite to satellite antenna 113 in the geostationary orbit plane, it is not necessary to adjust the geostationary satellite to satellite antenna 113 in an arbitrary direction. Good. Therefore, compared with the case of controlling two axes, there is an effect that a simple device is sufficient.

  Further, the antenna adjusting mechanism 173 may not be provided, and the stationary inter-satellite antenna 113 may be completely fixed to the main body of the satellite. In that case, the direction of the stationary inter-satellite antenna 113 is adjusted by the attitude control device of the satellite. If it does so, there exists an effect that the manufacturing cost of the communication satellite 100 can be suppressed further low.

For example, the communication satellite of this embodiment can be manufactured by the following process.
That is, the ground antennas 111 and 112 and the stationary inter-satellite antennas 113 (multiple antennas) are fixed to the main body of the communication satellite (antenna fixing step).
Next, the ground antennas 111 and 112 are connected to the ground communication unit (ground communication unit connection step).
Also, the geostationary satellite-to-satellite antenna 113 is connected to the satellite communication unit (step for connecting to the satellite communication unit).
And the relay part which relays communication between a ground communication part and a satellite communication part is connected (relay part connection process).

  In the antenna fixing step, the ground antennas 111 and 112 and the geostationary-satellite antenna 113 are directed in a predetermined direction determined so as to be able to communicate with a coverage designed in advance or a geostationary satellite according to the stationary position of the communication satellite. , Fixed to the main body of the communication satellite.

In the antenna fixing step, the ground antennas 111 and 112 and the stationary inter-satellite antenna 113 may be completely fixed to the main body of the communication satellite.
In that case, the antenna pointing direction is finely adjusted by the attitude control function of the communication satellite.

Further, the antenna adjustment mechanism 173 may be attached so that only a minute angle of about 0.2 degrees can be adjusted.
In that case, the antenna adjustment mechanism 173 finely adjusts the directivity direction of the antenna.

As described above, when the antenna directivity direction is finely adjusted by the attitude control function of the communication satellite without providing the antenna adjustment mechanism 173, the number of parts to be added is smaller than that of the existing communication satellite equipment. Since the manufacturing process is reduced, the manufacturing cost of the communication satellite can be reduced.
In addition, since the size and mass of the communication satellite do not increase, the launch cost can be suppressed.

  When the antenna adjustment mechanism 173 is provided, the manufacturing cost and the launch cost increase as compared with the case where the antenna adjustment mechanism 173 is not provided, but the increase is very large as compared with the case where the adjustment mechanism with a large angle is provided. It's small. Therefore, there are advantageous effects in terms of manufacturing cost and launch cost.

According to this embodiment, communication channels and coverage can be shared by performing inter-satellite communication among a plurality of geostationary satellites.
That is, in communication satellites, in particular, geostationary communication satellites, it is possible to relax restrictions on the communicable range due to fixed allocation of the stationary positions and service coverage of the communication satellites to each communication satellite, and to provide more flexible coverage. There is an effect.

The relative direction between the two geostationary satellites does not change. Therefore, it is relatively easy to add two or more geostationary satellite communication functions.
That is, with the addition of a minimum function, the communication repeater and antenna coverage of two or more geostationary satellites can be shared, and a more flexible service can be provided.

  Satellite communication / broadcasting operators usually have multiple satellites. For this reason, this embodiment which realizes expansion and change of service areas using a plurality of satellites with satellites may create a new communication / broadcasting business.

FIG. 9 is a block configuration diagram showing another example of the block configuration of the communication satellite 100 in this embodiment.
9, the communication satellite 100 has an input switch matrix 120a for the ground antenna 111 and an input switch matrix 120b for the ground antenna 112 instead of the input switch matrix 120 in the communication satellite 100 of FIG. .
In addition, the receiver group 130, the repeater group 140, and the output switch matrix 150 are also included in the receiver groups 130a and 130b, the repeater groups 140a and 140b, and the output switch matrices 150a and 150b for the respective input switch matrices 120a and 120b. I know. However, in order to arbitrarily connect the coverage 201 of the ground antenna 111 and the coverage 202 of the ground antenna 112, the outputs of the output switch matrices 150a and 150b are connected to the ground antennas 111 and 112, respectively.

  Thereby, the number of switches in the input switch matrices 120a and 120b and the output switch matrices 150a and 150b can be reduced. Although the utilization rate of repeaters and the like is lowered, there are advantageous effects in terms of manufacturing costs, launch costs, and the like.

  Further, an input dedicated port 181 is provided between the diplexer 163 and the input switch matrices 120a and 120b, and an output dedicated port 182 is provided between the output switch matrices 150a and 150b.

  As a result, it is possible to package the geostationary inter-satellite antenna 113, the diplexer 163, and the antenna adjustment mechanism 173, which are components added in comparison with the conventional communication satellite, so that the configuration can be connected to an existing geostationary satellite configuration. Is possible.

In this way, by introducing geostationary-satellite communications, two or more geostationary communications broadcasting satellites are connected, and two communications broadcasting service coverages and channels that are fixedly assigned to each geostationary satellite are connected. It can be shared by all the above satellites.
As a result, communication information or broadcast data can be exchanged only within the coverage of a single satellite in the past, but it is possible to freely exchange in a network in which a plurality of satellites are combined.

As a result, expansion of the service area, expansion of the degree of freedom of connection, change of the channel and service target corresponding to the change of the business environment, etc. can be arbitrarily performed and can be changed at any time.
For example, there is no need to launch a new satellite even if you want to communicate / broadcast between coverages of different geostationary satellites, such as when demand changes after launch or when a satellite breaks down. There is an effect that the time and cost corresponding to can be reduced.
That is, even if the coverages of a plurality of geostationary satellites are geographically separated, communication and broadcasting between the coverages are possible. In addition, flexible services can be provided according to changes in demand after launch.

According to this embodiment, a wide range of communication coverage can be realized.
A general communication satellite operator operates a plurality of satellites at a plurality of stationary positions. Since it becomes possible to couple | bond the communication repeater and antenna mounted in these satellites bidirectionally, it is possible to combine the areas where the respective communication satellites were independently serviced. That is, a wide range of service coverage that could not be realized by using a plurality of geostationary satellites can be realized with a minimum configuration of adding antenna channels between geostationary satellites.

In addition, it can flexibly respond to changes in the business environment even after launch.
Due to changes in the business environment, communication demand in the coverage covered by a certain geostationary satellite may increase or decrease. As a result, the satellite side repeaters that have become insufficient or excessive can be interchanged not only with the communication satellites equipped with the repeaters but also with stationary satellites that require more channels using mutual inter-satellite communication channels. Matching operation becomes possible. Therefore, it is possible to flexibly respond to changes in the business environment at low cost, and there is no need to plan additional geostationary satellites.

Furthermore, it is possible to respond quickly and at low cost to satellite failures.
Even if several repeaters of a certain geostationary satellite break down and there is no surplus in the redundant repeaters, there is no need to stop the service, so there is no loss of business opportunities. In other words, it is possible to use a surplus repeater of another geostationary satellite, so that it is possible to minimize a business opportunity loss due to a satellite failure.

Another advantage of this embodiment is that the configuration having the above-described effects can be realized at low cost.
In particular, when applied to a geostationary satellite, since it is a communication between geostationary satellites, the relative direction between one geostationary satellite and another geostationary satellite is fixed. Therefore, a large-scale and high-cost tracking type inter-satellite communication device required between a geostationary satellite and a low orbit satellite is unnecessary.
This embodiment can be realized by adding an inter-satellite antenna and an input / output of an inter-satellite channel to an existing switch matrix to the configuration of a conventional geostationary satellite. The added cost and weight can be minimized.
As for communication between geostationary satellites, even if the antennas between the stationary geostationary satellites are fixed, the required pointing error is within the range that can be compensated by the attitude control system of the satellite that is conventionally equipped, as shown in FIG. There is no need to add a tracking control device.

This also makes it possible to rent communication satellite equipment to other satellite operators.
In other words, the construction of a system consisting of two or more geostationary satellites can also be used as a backup when a geostationary satellite owned by another satellite operator breaks down. By renting, efficient business management can be achieved.

Further, if the adjustment angle of the antenna adjustment mechanism 173 is expanded so that the angle can be adjusted within a range of ± θ (θ <10 °), another stationary position within the range of the stationary position (longitude) ± 2θ. It is also possible to change the connection to the satellite.
That is, when there are multiple geostationary satellites of this embodiment, not only the connection to one of the geostationary satellites but also the other geostationary satellites can be fixed by driving the antenna between geostationary satellites with a small angle command and then fixing it. Connection is possible, and the connection between geostationary satellites in orbit can be flexibly changed by adjusting the bias angle (± several degrees) of the geostationary satellite communication antenna.

Embodiment 2. FIG.
The second embodiment will be described with reference to FIGS.

  Here, the case where it is developed into three or more geostationary satellites will be described.

FIG. 10 is a block configuration diagram showing an example of a block configuration of the communication satellite 100 in this embodiment.
The communication satellite 100 includes ground antennas 111 and 112, geostationary satellite antennas 113 and 114, an input switch matrix 120, a receiver group 130, a repeater group 140, an output switch matrix 150, diplexers 163 and 164, and antenna adjustment mechanisms 173 and 174. (An example of a direction adjustment unit).
Communication satellite 100 is the same as that described in Embodiment 1 with reference to FIG. 1 except that it has two geostationary satellite antennas 113 and 114, two diplexers 163 and 164, and two antenna adjustment mechanisms 173 and 174. Since there is, description is abbreviate | omitted here.

FIG. 11 is a diagram showing an example of a positional relationship when three communication satellites 100 in this embodiment are launched on a geostationary orbit and used as geostationary satellites 100a, 100b, and 100c.
As the geostationary satellites 100b and 100c, the communication satellite 100 described in the first embodiment may be used.

The geostationary satellite 100 a communicates with ground stations in the coverages 201 and 202 on the earth 200 via the ground antennas 111 and 112. Further, it communicates with the geostationary satellite 100c via the geostationary-satellite antenna 113 and with the geostationary satellite 100b via the geostationary-satellite antenna 114, respectively.
The geostationary satellite 100 b communicates with ground stations in the coverages 203 and 204 on the earth 200 via the ground antennas 111 and 112. Further, it communicates with the geostationary satellite 100a via the geostationary satellite antenna 113.
The geostationary satellite 100c communicates with ground stations in the coverages 205 and 206 (not shown) on the earth 200 via the ground antennas 111 and 112. Further, it communicates with the geostationary satellite 100a via the geostationary satellite antenna 113.

  FIG. 4 is a diagram illustrating an example of the coverages 201 to 206 of the geostationary satellites 100a, 100b, and 100c in this embodiment.

  FIG. 12 is a diagram showing an example of the operation of the geostationary satellites 100a, 100b, and 100c in this embodiment.

For example, the uplink station 216 within the coverage 206 of the geostationary satellite 100c transmits a signal.
In the geostationary satellite 100 c, the ground antenna 112 receives this, and the geostationary intersatellite antenna 113 transmits via the receiver 136, the repeater 146, and the diplexer 163.
In the geostationary satellite 100a, the geostationary intersatellite antenna 113 receives this, and the geostationary intersatellite antenna 114 transmits via the diplexer 163, the receiver 131, the repeater 141, and the diplexer 164.
In the geostationary satellite 100b, the geostationary satellite antenna 113 receives this, and the ground antenna 112 transmits the signal via the diplexer 163, the receiver 133, and the repeater 143.
This is received by a downlink station 224 within the coverage 204 of the geostationary satellite 100b.

  Thus, if the geostationary satellite 100a relays communication between the geostationary satellite 100b and the geostationary satellite 100c, the geostationary satellite 100b and the geostationary satellite 100c cannot communicate directly (for example, just across the earth 200 on the opposite side). Even if it is a shadow of the earth 200 because it is located, communication between the mutual coverages can be made possible.

  Similarly, the signal transmitted by the uplink station 213 in the coverage 203 reaches the downlink station 221 in the coverage 201 via the geostationary satellites 100b and 100a.

  Further, the signal transmitted by the uplink station 215 in the coverage 205 reaches the downlink station 226 in the coverage 206 via the geostationary satellite 100c.

  In this way, communication between arbitrary coverages is possible by freely changing the number of geostationary satellites to be relayed.

FIG. 13 is a conceptual diagram showing an example of communication between coverages enabled by this embodiment.
As described above, according to this embodiment, it is possible to communicate not only between the coverages of stationary satellites that can communicate with each other but also between the coverages of stationary satellites that cannot communicate directly (indicated by broken lines in the figure). Play.

In this way, by introducing a plurality of geostationary-satellite communications, 3 or more geostationary communications broadcasting satellites are connected, and the service coverage and channels of communications broadcasting that are fixedly assigned to each geostationary satellite are connected. It can be shared by all satellites above the plane.
As a result, communication information or broadcast data can be exchanged only within the coverage of a single satellite in the past, but it is possible to freely exchange in a network in which a plurality of satellites are combined.

As described above, this embodiment can be developed to three or more geostationary satellites.
In this case, a wider range of service coverage can be configured.
That is, in order to connect three geostationary satellites, two intersatellite communication antennas are mounted on one of the three geostationary satellites.
Compared to a service using one geostationary satellite, it is possible to dramatically improve the degree of freedom of connection.

  Furthermore, for example, by connecting four geostationary satellites whose geostationary longitudes are 90 degrees apart with adjacent satellites by inter-satellite communication, communication / broadcasting services between almost all regions in the world are possible.

FIG. 14 is a block configuration diagram showing another example of the block configuration of the communication satellite 100 in this embodiment.
14, in addition to the communication satellite 100 described with reference to FIG. 1 in the first embodiment, the communication satellite 100 includes an inter-stationary satellite antenna 114, a diplexer 163, an antenna adjustment mechanism 174, and changeover switches 191 and 192. ing.

The changeover switch 191 selects one of the inputs from the diplexers 163 and 164 and outputs it to the input switch matrix 120.
The changeover switch 192 selects and outputs one of the diplexers 163 and 164 from the output switch matrix 150.

  Thus, the number of switches in the input switch matrix 120 and the output switch matrix 150 can be reduced as compared with the configuration described in FIG. Although the degree of freedom of connection is reduced, there are advantageous effects in terms of manufacturing cost, launch cost, and the like.

  The contents described above will be supplementarily explained.

FIG. 15 is a diagram showing an example of a part added to the prior art necessary for configuring the present invention. .
For each of the plurality of geostationary satellites, an antenna 113 between the geostationary satellites as an antenna system, an antenna adjustment mechanism 173 (micro angle adjustment motor) and a motor drive circuit 175 as a minute angle adjustment system, a diplexer 163 and a dedicated input port 181 as a relay system A dedicated output port 182 is provided and connected to the existing geostationary satellite configuration.
The antenna adjustment mechanism 173 only needs to be able to adjust one axis or two axes, and does not require tracking control by only fine adjustment of the bias for directing to other geostationary satellite directions.
Since the motor drive circuit 175 is between geostationary satellites, only a fine adjustment angle is required.
Therefore, the antenna adjustment mechanism 173 and the motor drive circuit 175 can be realized with a simple configuration, and the number of parts, the volume, and the weight are small.
As described above, since there are few parts to be added to the configuration of the existing geostationary satellite, the satellite can be operated efficiently without significantly increasing the manufacturing cost, the launch cost, and the like. Play.

With the inter-stationary satellite communication of the present invention, for example, as shown in FIG. 11, communication channels of a plurality of satellites are connected, and coverage can be shared.
Thus, bidirectional communication between the antenna coverages 201 and 202 to the antenna coverages 203 and 204 becomes possible by relaying communication between a plurality of geostationary satellites using the present invention.
That is, by introducing one or more geostationary satellite communications, two or more geostationary communications broadcast satellites were connected, and the service coverage and channels of communication broadcasting that were fixedly assigned to each geostationary satellite were connected. It can be shared by all satellites of two or more.
For example, the relays / channels of the geostationary satellite 100a and 100b can be shared by communication between the geostationary satellite 100a and the geostationary satellite 100b, and the antenna coverage 201 and 202 of the geostationary satellite 100a and the antenna coverage 2003 of the geostationary satellite 100b. , 204 can be communicated with each other.
Alternatively, the relays / channels of the geostationary satellite 100a and 100c can be shared by communication between the geostationary satellite 100a and the geostationary satellite 100c, and the antenna coverages 201 and 202 of the geostationary satellite 100a and the antenna coverage 205 of the geostationary satellite 100c. , 206 can be bidirectionally communicated.
Thus, conventionally, communication information or broadcast data can be exchanged only within the coverage of one satellite, but it is possible to freely exchange in a network in which a plurality of satellites are combined.

In the prior art, communication can be performed only within the coverage of the antenna beam of a single satellite.
Since the coverage is determined by the direction of the antenna beam of the ground antenna, it cannot be changed later.
That is, when the satellite 1 has the antenna beams 1 and 2, the service areas 1 A and 1 B and the service areas 2 A and 2 B or the gateway station 2 C attached to the antenna beam 1 and the antenna beam 2 inherent to the satellite 1, It is limited to an intercommunication service or a broadcast service only between 2D.

According to the present invention, a service area can be connected by connecting a plurality of satellites.
For example, service areas 231a to 231c and a gateway station 241 are attached to the antenna beam coverage 201 inherently possessed by the geostationary satellite 100a of FIG.
The coverage 202 is accompanied by service areas 232a and 232b and a gateway station 242.
Similarly, service areas 233a to 233d are attached to the antenna beam coverage 203 inherent to the geostationary satellite 100b, and service areas 234a and 234b and gateway stations 244a and 244b are attached to the coverage 204.
By connecting these coverages 201 to 204 to each other as shown in FIG. 6, communication / broadcasting services can be performed between the entire system including all of the service areas 231a to 234b and the gateway stations 241 to 244b. Become.
It is possible to arbitrarily change channel and service target corresponding to expansion of service area, expansion of freedom of connection, and change of business environment, and can be changed at any time.

According to the conventional concept of communication services using geostationary satellites, service coverage is fixed for each satellite.
In other words, in communication satellites, especially geostationary communication satellites, a fixed antenna coverage is supplied to the ground coverage that is serviced from a fixed stationary position for each satellite, and each channel of the repeater is fixedly allocated to this antenna coverage. Alternatively, the communication service is supplied by switching with a switch in the satellite.
Therefore, the service coverage for one geostationary satellite is fixed to one type by the coverage of a plurality of mounted antennas, and of course, communication broadcasting service is not possible for other service coverage that cannot be seen from the stationary position.
Since the geostationary satellite 1 can communicate only within the antenna coverage of the geostationary satellite 1 and the geostationary satellite 2 can communicate only within the coverage of the geostationary satellite 2, communication and broadcasting between the coverages are impossible if the coverage is geographically separated. It is impossible to change the coverage after the service is started, and a flexible service according to the change in demand after the launch is not possible. Even if the stationary position is changed, the antenna pattern is designed for each stationary position, so that it is not possible to provide optimum coverage.
In other words, even if it is desired to communicate or broadcast from Coverage 1 to Coverage 2 due to demand changes after launch or failure of the satellite, or vice versa, it is necessary to launch a new satellite, and the time / Cost is high.

  Conventionally, some geostationary satellites have a function to relay the data acquired by the low-orbit orbit satellite from the geostationary relay satellite to the ground station. For this reason, a geostationary relay satellite needs a tracking function with a large angle, and there is a problem of high cost, large scale, and mass power increase.

  A geostationary relay satellite that communicates with such a low-orbit orbiting satellite requires a large antenna tracking angle as shown in FIG.

  The present invention uses the components shown in FIG. 15 as examples of necessary components (an antenna between geostationary satellites, a minute angle adjustment motor and motor drive circuit, a diplexer, an input-only port, an output-only port) for existing geostationary satellites. Since it can be configured simply by adding, it is effective in reducing the additional cost.

FIG. 16 is a diagram illustrating an example of communication channel and coverage sharing by communication between a plurality of (two examples) geostationary satellites 100a and 100b.
The connection between the coverages 201 and 202 of the geostationary satellite 100a and the coverages 203 and 204 of the geostationary satellite 100b is shown.
For example, as indicated by a bold line, a signal transmitted by the user uplink station 211 in the coverage 201 is received by the antenna 111a of the geostationary satellite 100a and is input to the receiver 131a via the input switch matrix 120a. The output of the receiver 131a is amplified by the repeater 141a and input to the diplexer 163a via the output switch matrix 150a. The output of the diplexer 163a is transmitted to the geostationary satellite 100b by the inter-satellite communication antenna 113a.
In the geostationary satellite 100b, the inter-satellite communication antenna 113b receives this and inputs it to the diplexer 163b. The output of the diplexer 163b is input to the receiver 131c via the input switch matrix 120c. The output of the receiver 131c is amplified by the repeater 141c, transmitted by the antenna 112b via the output switch matrix 150c, and received by the user downlink station 224 in the coverage 204.
Similarly, by following a route indicated by a dotted line, communication from the user uplink station 213 in the coverage 203 to the user downlink station 212 in the coverage 201 can be performed.
In this way, communication / broadcasting between coverages of a plurality of geostationary satellites becomes possible.
With the conventional configuration, only the user uplink station 211 relays to the user downlink station 221 in the same coverage within the antenna coverage 201a included only in the geostationary satellite 100a. By realizing the bold line of the present invention, the user down in the coverage 203 covered by the geostationary satellite 100b from the user uplink station 211 in the antenna coverage 201 included in the geostationary satellite 100a through the relay line for inter-geostationary satellite communication is achieved. Connection to the link station 223 is also possible.
The reverse is also possible. With the conventional configuration, only the user uplink station 213 is relayed to the user downlink station 223 in the same coverage in the antenna coverage 203 included only in the geostationary satellite 100b. Since the dotted line of the present invention is realized at the same time, the user in the coverage 202 covered by the geostationary satellite 100a from the user uplink station 213 in the antenna coverage 203 included in the geostationary satellite 100b through the relay line for geostationary satellite communication. Connection to the downlink station 222 is also possible.

  Thereby, conventionally, for example, only the connection between the coverage 201 and the coverage 202 in FIG. 6 or between the coverage 203 and the coverage 204 was possible, but connection between all the coverages 201 to 204 is possible. It becomes.

  The requirement for the directivity angle of the inter-satellite antenna is normally ± 0.1 ° to 0.2 ° (standard value, broken line in FIG. 7). If the satellite orientation can be correctly controlled by controlling the attitude of the satellite, the directivity is The angle error (solid line in FIG. 7) is smaller than this.

Furthermore, as shown in FIG. 11, it is possible to connect three or more geostationary satellites.
As described above, if two geostationary satellite communication antennas are added to one geostationary satellite (geostationary satellite 100a), communication between the geostationary satellite 100b and the geostationary satellite 100c, which cannot perform direct communication, can be relayed.

  Thereby, for example, the connection indicated by the solid line arrow in FIG. 13 is not only possible, but also the connection indicated by the broken line arrow is possible.

FIG. 2 is a block configuration diagram showing an example of a block configuration of a communication satellite 100 in the first embodiment. The figure which shows an example of operation | movement at the time of launching the two communication satellites 100 in Embodiment 1 on a geostationary orbit, and operating as a geostationary satellite 100a, 100b. FIG. 3 shows an example of a positional relationship between geostationary satellites 100a and 100b and the earth 200 in the first embodiment. FIG. 3 shows an example of coverages 201 to 204 of geostationary satellites 100a and 100b in the first embodiment. FIG. 3 is a diagram illustrating an example of a communication service supplied by the first embodiment. FIG. 3 is a conceptual diagram illustrating an example of communication between coverages enabled by the first embodiment. The figure which shows an example of the time-sequential change of the direction of the geostationary satellite 100b seen from the geostationary satellite 100a in Embodiment 1. The figure which shows an example of the time-sequential change of the direction of a low orbit orbit satellite seen from a geostationary satellite. FIG. 4 is a block configuration diagram showing another example of the block configuration of the communication satellite 100 according to the first embodiment. FIG. 4 is a block configuration diagram showing an example of a block configuration of a communication satellite 100 in a second embodiment. The figure which shows an example of the positional relationship at the time of launching the three communication satellites 100 in Embodiment 2 on a geostationary orbit, and operating as the geostationary satellites 100a, 100b, and 100c. The figure which shows an example of operation | movement of the geostationary satellites 100a, 100b, 100c in Embodiment 2. FIG. FIG. 9 is a conceptual diagram illustrating an example of communication between coverages enabled by the second embodiment. FIG. 10 is a block configuration diagram showing another example of a block configuration of the communication satellite 100 according to the second embodiment. The figure which shows an example of the addition part to the prior art required in order to comprise this invention. The figure which shows an example of the sharing of the communication channel and coverage by the communication between several geostationary satellites (example of 2 apparatuses).

Explanation of symbols

  100 communication satellite, 100a, 100b, 100c geostationary satellite, 111,112 ground antenna, 113,114 geostationary satellite, 120 input switch matrix, 130 receiver group, 131-134 receiver, 140 repeater group, 141-144 Repeater, 150 output switch matrix, 163,164 diplexer, 173,174 antenna adjustment mechanism, 175 motor drive circuit, 181 input dedicated port, 182 output dedicated port, 191,192 changeover switch, 200 earth, 201-206 coverage 211-216 Uplink stations, 221-226 Downlink stations, 231a-234b Service areas, 241-244b Gateway stations.

Claims (4)

In communication satellites operating in geostationary orbit,
The satellite body,
A ground antenna having directivity for directing a fixed direction with respect to the satellite body;
A geostationary satellite-to-satellite antenna having directivity directed in a predetermined direction;
The direction in which the stationary inter-satellite antenna is directed is adjusted within a range of ± 0.2 degrees around the direction fixed to the satellite body and different from the direction in which the ground antenna is directed. A direction adjustment unit to perform,
A receiver for receiving signals via the ground antenna or the geostationary satellite antenna;
A relay unit for transmitting a signal received by the receiving unit via the ground antenna or the geostationary satellite antenna;
A predetermined range on the ground is positioned in a direction in which the ground antenna is directed, and another communication satellite operated at a position different from the communication satellite on the geostationary orbit is in a direction in which the inter-stationary satellite antenna is directed. A communication satellite comprising an attitude control device that controls the attitude of the satellite body so as to be positioned. In communication satellites operating in geostationary orbit,
The satellite body,
A ground antenna having directivity for directing a fixed direction with respect to the satellite body;
A first stationary inter-satellite antenna having a directivity that is directed in a direction that is fixed to the satellite body and that is different from the direction in which the ground antenna is directed;
A second geostationary intersatellite antenna having directivity that directs in a predetermined direction;
The direction in which the second stationary inter-satellite antenna is directed is a direction fixed to the satellite body, the direction in which the ground antenna is directed and the direction in which the first stationary inter-satellite antenna is directed. A direction adjustment unit that adjusts within a range of ± 0.2 degrees around a different direction from each other;
A receiver for receiving signals via the ground antenna or the first geostationary satellite antenna or the second geostationary satellite antenna;
A relay unit for transmitting a signal received by the receiving unit via the ground antenna, the first geostationary satellite antenna, or the second geostationary satellite antenna;
A predetermined range on the ground is located in the direction in which the ground antenna is directed, and another communication satellite operated at a position different from the communication satellite on the geostationary orbit is directed to the first geostationary satellite antenna. And another communication satellite operated at a position different from any of the communication satellite and the other communication satellite on the geostationary orbit is in a direction in which the second inter-stationary satellite antenna is directed. A communication satellite comprising an attitude control device that controls the attitude of the satellite body so as to be positioned. In communication satellites operating in geostationary orbit,
The satellite body,
A ground antenna having directivity for directing a fixed direction with respect to the satellite body;
A first geostationary-satellite antenna having directivity directed in a predetermined direction;
The direction in which the first stationary inter-satellite antenna is directed is a direction that is fixed with respect to the satellite body and that is within ± 0.2 degrees centered on a direction different from the direction in which the ground antenna is directed. A first direction adjustment unit for adjusting the range;
A second geostationary intersatellite antenna having directivity that directs in a predetermined direction;
The direction in which the second stationary inter-satellite antenna is directed is a direction fixed to the satellite body, the direction in which the ground antenna is directed and the direction in which the first stationary inter-satellite antenna is directed. A second direction adjustment unit that adjusts within a range of ± 0.2 degrees around a different direction from each other;
A receiver for receiving signals via the ground antenna or the first geostationary satellite antenna or the second geostationary satellite antenna;
A relay unit for transmitting a signal received by the receiving unit via the ground antenna, the first geostationary satellite antenna, or the second geostationary satellite antenna;
A predetermined range on the ground is located in the direction in which the ground antenna is directed, and another communication satellite operated at a position different from the communication satellite on the geostationary orbit is directed to the first geostationary satellite antenna. And another communication satellite operated at a position different from any of the communication satellite and the other communication satellite on the geostationary orbit is in a direction in which the second inter-stationary satellite antenna is directed. A communication satellite comprising an attitude control device that controls the attitude of the satellite body so as to be positioned. A communication satellite according to any one of claims 1 to 3 ,
The communication satellite according to any one of claims 1 to 3 , wherein the communication satellite is operated at a position on a geosynchronous orbit to which an antenna between the geostationary satellites of the communication satellite is directed, and the antenna in the direction in which the antenna between the geostationary satellites points With other communication satellites where communication satellites are located,
A first ground station located in a predetermined range on the ground located in a direction in which the ground antenna of the communication satellite is directed, and communicating with the communication satellite;
A communication system, comprising: a second ground station that is located within a predetermined range on the ground and is positioned in a direction in which a ground antenna of the other communication satellite is directed, and that communicates with the other communication satellite.

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