JPH1127195A - Communication system and receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To observe the earth or other heavenly bodies and to distribute the observed images in real time. SOLUTION: This communication system consists of a ground station 1, a satellite 2 which receives signals from the station 1 and transmits these signals again, and a receiving station 3 which receives the signals from the satellite 2. A camera 11 is attached to the satellite 2 to photograph the observed images sent from the satellite. The satellite 2 multiplexes together the signals photographed by the camera 11 and the signals received from the station 1, and sends these multiplexed signals to the station 3. As a result, the images of the earth or other heavenly bodies which are viewed in the outer space can be distributed in real time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system using satellites and a receiving device therefor, and more particularly to a system which enables direct viewing of images from satellites.

[0002]

2. Description of the Related Art A number of satellites have been launched in orbit around the earth, and from these satellites, a large number of images of the earth and other celestial bodies viewed from space have been transmitted. These images provide valuable information for academic research.

[0003] For example, when a comet approaches the earth, a visible, X-ray, infrared, etc.
Electromagnetic waves are received by various cameras and sent to the earth. This information is analyzed by specialized laboratories to analyze comets approaching Earth. Furthermore, the results of this analysis are broadcast on television or published in magazines, so that the state of a comet approaching the earth can be known.

Further, NASA (Federal Aeronautics and Space Administration) and the like provide programs for broadcasting images taken by satellite. Such programs allow you to see the state of the earth and other celestial bodies from space in real time. Such programs are not only important for academic purposes, but also the observation of the ever-changing state of the earth and celestial bodies is simply interesting.

[0005] In recent years, awareness of the global environment has been increasing, and such programs are also useful for raising the awareness of the global environment. In addition, astronomical enthusiasts climb the clear mountains of the air, observe astronomical objects with astronomical telescopes, etc., and appreciate various astronomical objects. It is thought to provide interesting images.

[0006]

However, in the above-mentioned conventional broadcasting program, an image taken by an academic astronomical observation satellite or a meteorological satellite or the like is once taken into a ground station, and then used by terrestrial broadcasting or satellite broadcasting. And distribute it again. For this reason, there is a problem that an observation image cannot be obtained in real time.

[0007] Further, in the above-mentioned conventional broadcast program, an image captured by a ground station is distributed again by using a terrestrial broadcast or a satellite broadcast, so that a viewer can see only an image of a fixed scene. . If the user can interactively control the position of the observation camera mounted on the satellite, more interesting images can be seen.

Accordingly, it is an object of the present invention to provide a communication system and a receiving apparatus capable of observing the earth or a celestial body other than the earth and distributing the obtained observation image in real time.

It is another object of the present invention to provide a communication system and a receiving apparatus which can easily change the position and size of an image to be observed.

[0010]

SUMMARY OF THE INVENTION The present invention comprises a ground station,
In a communication system including a satellite that receives and retransmits a signal from a ground station and a receiving station that receives a signal from the satellite, the satellite is captured by a camera that captures an observation image from the satellite, and captured by the camera. A communication system comprising: a multiplexing unit that multiplexes a signal and a received signal from a ground station.

According to the present invention, in a receiving apparatus for receiving a video signal transmitted from a ground station via a satellite, a camera for photographing an observation image from the satellite is attached to the satellite, and the camera is photographed from the satellite. The received signal from the ground station and the received signal from the ground station are multiplexed and transmitted, and include a storage unit that stores a signal captured by a camera, and a screen processing unit that processes a screen stored in the storage unit. This is a receiving device.

A video camera is mounted on the outer surface of a communication satellite, and images from the video camera are multiplexed with a satellite broadcast signal and transmitted. As a result, the state of the earth and other celestial bodies viewed from space can be viewed in real time.

On the receiving side, a screen processing circuit and a memory are provided. The image from the video camera is processed by the screen processing circuit and projected. By operating the screen stored in the memory by the screen processing circuit, an operation similar to operating a video camera or operating a zoom can be performed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of an image transmission system to which the present invention is applied. FIG.
, 1 is a ground station for transmitting a television broadcast program, 2 is a satellite, and 3 is a receiving system of each home.

The satellite 2 is a geostationary satellite launched in a geosynchronous orbit, and includes a communication system including a transmitting / receiving antenna and a transponder, a power system including a solar cell panel 4 and the like,
Attitude control system and TT & C (Tracking, Telemetry and Com
mand) system and propulsion system. Satellite 2
As BS (Broadcasting Satellite) or CS
(Communication Satellite) can be used.

The attitude of the satellite 2 is controlled as needed so that it is always constant in three directions. That is, the attitude is controlled so that the directional relationship between the direction perpendicular to the orbital plane, the direction traveling in the orbital plane, and the earth is always constant.

From the transmitting antenna 4 of the ground station 1, a video signal to be delivered to the receiving system 3 of each home is output at a predetermined frequency. The signal from the ground station 1 is received by the satellite 2. The transponder of the satellite 2 converts this signal to a predetermined frequency. Then, it is transmitted from the broadcasting satellite 2 to the receiving system 3 of each home.

An uplink from the ground station 1 to the satellite 2 is called an uplink, and a downlink from the satellite 2 to the receiving system 3 in each home is called a downlink. As a frequency band of satellite broadcasting, a C band or a Ku band of a microwave band is used. For example, when the Ku band is used, the uplink frequency is 14 GHz.
The z band is used and the downlink frequency is 12 GHz
The z band is used.

Further, in this example, a video camera 11 is attached to the satellite 2, and a state from space captured by the video camera 11 is directly sent to the receiving system 3 of each home. I have.

The receiving system 3 in each home includes a receiving antenna 6 and a television receiver to which a dedicated tuner is attached. In addition, the ground station 1
In some cases, a dedicated external control device may be provided for communicating with the user and performing collation and billing of the contractor.

From the ground station 1, a television broadcast program is transmitted. This television broadcast program is received by the receiving system 3 at each home via the satellite 2. Thereby, the television broadcast program transmitted from the ground station 1 via the satellite 2 can be enjoyed by the receiving system 3 of each home.
Further, in this example, a video camera 11 is attached to the satellite 2. For this reason, the receiving system 3 of each home
Thus, an image from space captured by the video camera of the satellite 2 can be viewed.

FIG. 2 shows an external configuration of the satellite 2 to which the video camera 11 is attached. As shown in FIG. 2, on the outer surface of the satellite 2, a receiving antenna 12 for receiving a signal from the ground station 1 and a transmitting antenna 13 for transmitting a signal to the receiving system 3 of each home are arranged. The video camera 11 is attached. This video camera 1
1 captures an image from space viewed from the satellite 2. A video signal of an image from space captured by the video camera 11 is multiplexed with a signal transmitted from the ground station 1 via the satellite 2 and transmitted to the receiving system 3 in each home.

As described above, in order to multiplex the video signal from the video camera 11 and the video signal from the ground station 1, the multiplexing circuit as shown in FIG. ing.

FIG. 3 shows a video signal transmitted from the ground station 1 via the satellite 2 to a video signal from space captured by the video camera 11 which is frequency-division multiplexed and transmitted to the receiving system 3 in each home. FIG. 3 shows an example of the configuration of a repeater arranged on the satellite 2 in the case of the above.

In FIG. 3, a signal from the ground station 1 is received by a receiving antenna 12, and the received signal is supplied to a mixer 22 via a low noise amplifier 21. Mixer 2
2, the output of the local oscillator 23 is supplied. Mixer 2
In 2, the uplink frequency signal received by the receiving antenna 12 is converted to a downlink frequency band signal. The output of the mixer 23 is supplied to a multiplexing circuit 24.

Video camera 11 mounted on satellite 2
Is supplied to the A / D converter 15. A
The video signal from the video camera 11 is digitized by the / D converter 25. The output of the A / D converter 25 is supplied to a compression circuit 26.

The compression circuit 26 is, for example, an MPEG (Movi)
ng Picture Experts Group) 2 and a compression circuit 26 compresses and encodes video data. The output of the compression circuit 26 is supplied to the modulation circuit 27.
The modulation circuit 27 modulates a carrier of a predetermined channel of the downlink. The output of the modulation circuit 27 is supplied to the multiplexing circuit 24.

The multiplexing circuit 24 multiplexes the signal from the ground station 1 and the image channel signal from the video camera 11. The output of the multiplexing circuit 24 is supplied to a power amplifier 28. The power amplification amplifier 28 power-amplifies the transmission signal. The output of the power amplification amplifier 28 is supplied to the transmitting antenna 13 and transmitted to the receiving system 3 of each home on the earth.

That is, as shown in FIG. 4A, of the channels 1 to N, the frequency band of the channel K is
Are reserved for transmitting an image from the video camera 11 attached to the ground station 1, and the other channels are used for broadcasting from the ground station 1. As shown in FIG. 3B, the frequency band of channel K is used as a channel for transmitting an image from video camera 11. As shown in FIG. 3C, the multiplexing circuit 24 outputs a broadcast channel signal from the ground station 1 shown in FIG.
B is multiplexed with an image channel signal from the video camera 11 attached to the satellite 2. The multiplexed signal is output from the satellite 2.

As described above, the satellite 2 has the video camera 1
1 is attached, and an image captured by the video camera 11 is transmitted using the channel K. Therefore, the viewer of the receiving system 3 in each home can directly view an image of the earth viewed from space in real time simply by setting the receiving channel to the K channel.

In the above example, the signal from the ground station 1 and the signal from the video camera 11 attached to the satellite 2 are frequency division multiplexed. However, time division multiplexing or code division multiplexing is performed. You may do it.

In the above example, the video camera 11 attached to the satellite 2 is fixed, but it is desired that the orientation of the video camera 11 can be controlled. Therefore, it is conceivable to provide a drive motor for the video camera 11 so that the direction of the video camera 11 can be freely changed.

FIGS. 5 and 6 show an example in which the direction of the video camera 11 can be changed by a command from the ground station 1. FIG. As shown in FIG. 5, the video camera 11 is provided with a camera driving unit 30 including a two-axis driving mechanism and a motor. The camera drive unit 30 enables the direction of the video camera 11 to move in two axial directions. Further, the zoom of the video camera 11 can be moved by the camera driving unit 30.

The ground station 1 is provided with a computer for operating the video camera 11.
A control signal for moving the video camera 11 is sent from the computer. An antenna 31 for receiving the control signal is attached to the satellite 2. The satellite 2 receives the control signal as shown in FIG.
Thus, a driving system circuit for operating the camera driving unit 30 is provided.

In FIG. 6, a control signal from the ground station 1 is received by an antenna 31, and this signal is supplied to a mixer 33 via a low noise amplifier 32. Mixer 3
The output of the local oscillator 34 is supplied to 3. Mixer 3
3 is supplied to the demodulation circuit 35. The data is demodulated by the demodulation circuit 35. The demodulated data is supplied to the control circuit 36.

To move the video camera 11, a command for moving the video camera is sent from the ground station 1. This command is demodulated by the demodulation circuit 35 and supplied to the control circuit 36. The control circuit 36 determines the control direction and control amount of the video camera 11 according to the command. Thereby, the camera driving unit 30 is driven, and the video camera 11 is moved.

Thus, according to the command from the ground station 1,
It is possible to freely control the video camera in a desired direction. Therefore, it is possible to control the video camera 11 to face the earth when the user wants to photograph the earth, and to control the video camera 11 to face the moon when he wants to photograph the moon. Furthermore, it is possible to track and photograph moving objects such as Halley's comet.

Furthermore, if the viewer can freely control the direction of the video camera 11 in addition to the operation at the ground station 1,
You can have a simulated experience like riding on a satellite,
It will be interesting. To enable the viewer to freely control the direction of the video camera 11, as shown in FIG. 7, the viewer's personal computer 38 of the receiving system 3 and the computer 39 of the ground station 1 are connected to the Internet 40 or the like. It is possible if they are connected by. Further, a control system that can be connected to the computer of the ground station 1 may be incorporated in the viewer's receiving system 3.

In the above example, one video camera 11 is attached to the satellite 2, but as shown in FIG.
A plurality of video cameras 11A, 11B, 11C,... May be attached. Multiple video cameras 11
A, 11B, 11C,... Are attached, and the direction and magnification of each video camera 11A, 11B, 11C,. become able to.

Further, for example, when a multi-screen configuration capable of simultaneously displaying a plurality of screens is used as the receiving system 3 in each home, as shown in FIG. 9A, a plurality of video cameras 11A, 11B, 11C, .. Can be displayed at once. Then, a desired image is selected from the images, and the image of the selected video camera can be displayed as shown in FIG. 9B.

FIG. 10 shows an example of the receiving system 3 capable of multi-screen display. In FIG. 10, a radio wave from the satellite 2 is received by the receiving antenna 6. From satellite 2,
The images from the plurality of video cameras 11A, 11B, 11C,... Are time-division multiplexed and sent. This received signal is supplied to the tuner circuit 43 via an external converter (not shown).

In the tuner circuit 43, a predetermined channel signal is selected based on a control signal from the control circuit 51, and this signal is converted into an intermediate frequency signal. The output of the tuner circuit 43 is supplied to the demodulation circuit 4 via the intermediate frequency circuit 44.
5 is supplied. The output of the demodulation circuit 45 is supplied to the MPEG2 decoder 46.

The MPEG2 decoder 46 decodes the video signal compressed by MPEG2. This MP
The output of the EG2 decoder 46 is supplied to the screen processing circuit 47. An image memory 48 is connected to the screen processing circuit 47. The screen processing circuit 47 performs an image conversion process based on a control signal from the control circuit 51. The screen processing circuit 47 can perform multi-screen processing such as dividing one screen into a plurality of screens. The output of the screen processing circuit 47 is supplied to the video processing circuit 49. The output of the video processing circuit 49 is supplied to the picture tube 50.

As described above, the screen processing circuit 47 is provided in the satellite broadcast receiving system, and the screen processing circuit 47 can form a multi-screen.
A command from the remote controller 53 is supplied to the control circuit 51 via the light receiving unit 52. By operating the remote controller 53, a plurality of video cameras 11A, 11B, 11B as shown in FIG.
A list of images from C,... Can be displayed. 9B by operating the remote controller 53.
As shown in (1), a desired image can be selected from these and projected.

By the way, as described above, if the viewer can freely control the direction of the video camera 11, the user can have a simulated experience like riding on a satellite, which is more interesting. As shown in FIG. 7, if the personal computer 38 of the viewer and the computer 39 of the ground station 1 are connected via the Internet 40, the viewer can freely control the direction of the video camera 11. However, in this case, a plurality of persons cannot control the direction of the video camera 11 at the same time. Also, controlling the direction of the video camera 11 by the viewer may cause management problems.

As shown in FIG. 10, when a receiving system provided with a memory 48 and a screen processing circuit 47 is used,
By controlling the cutout position of the screen, as if directly controlling the direction of the video camera 11,
Display can be performed.

That is, the screen sent from the video camera 11 is stored in the memory 48. As shown in FIG. 11, the address space A0 of the memory 48 is larger than the screen A1 actually displayed on the screen. In response to a command from the control circuit 51, a screen A1 corresponding to the actual screen size is selected from the images stored in the memory 48.
Is cut out and output. By moving the cutout address of this screen A1 in the vertical direction or the horizontal direction,
The screen moves as if the video camera 11 was moved in the vertical direction or the horizontal direction. In addition, the image stored in the memory 48 is thinned out or interpolated by a command from the control circuit 51, so that the screen can be enlarged or reduced as if the zoom of the video camera is being moved. it can.

In this case, it is necessary to store in the memory 48 an image larger than the information of the screen actually projected on the screen. Therefore, a plurality of video cameras 11A, 11B, 1
It is conceivable that the images obtained from 1C,... Are stored in the memory 48 corresponding to the respective positions. Further, an ultra wide angle lens may be used as the video camera 11. In addition, the transmitted screen is enlarged and interpolated to the memory 4.
8 may be stored.

In this way, without moving the video camera 11, the viewer can see an image from space while moving the viewpoint, as if moving the video camera 1.

In the above example, the video camera is attached to the geostationary satellite. However, a satellite other than the geostationary satellite may be used. For example, a low-orbit satellite used in a mobile phone system or the like may be used.

As a camera attached to the satellite, a still image camera may be attached in addition to a moving image camera. You can also attach filters to the camera,
A camera that captures special electromagnetic waves such as X-rays and infrared rays may be attached.

[0052]

According to the present invention, a video camera is mounted on the outer surface of a communication satellite, and an image from the video camera is multiplexed with a satellite broadcast signal and transmitted. As a result, the state of the earth and other celestial bodies viewed from space can be viewed in real time.

On the receiving side, a screen processing circuit and a memory are provided. The image from the video camera is processed by the screen processing circuit and projected. By operating the screen stored in the memory by the screen processing circuit, an operation similar to operating a video camera or operating a zoom can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an outline of a communication system to which the present invention is applied.

FIG. 2 is a perspective view of an example of a satellite in a communication system to which the present invention is applied.

FIG. 3 is a block diagram of an example of a repeater arranged on a satellite in a communication system to which the present invention is applied;

FIG. 4 is a frequency spectrum diagram used for describing a communication system to which the present invention is applied.

FIG. 5 is a perspective view of another example of the satellite in the communication system to which the present invention is applied.

FIG. 6 is a block diagram used to explain a control mechanism of a camera in a communication system to which the present invention is applied.

FIG. 7 is a block diagram used for describing camera operation in a communication system to which the present invention has been applied.

FIG. 8 is a perspective view of still another example of the satellite in the communication system to which the present invention is applied.

FIG. 9 is a schematic diagram used for explaining multi-screen display.

FIG. 10 is a block diagram showing an example of a configuration of a receiving side in a communication system to which the present invention is applied.

FIG. 11 is a schematic diagram used for describing virtual camera movement.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ground station, 2 ... Satellite, 3 ... Receiving system, 11 ... Video camera, 24 ... Multiplexing circuit,

Claims (10)

[Claims] 1. A communication system comprising a ground station, a satellite for receiving and retransmitting a signal from the ground station, and a receiving station for receiving a signal from the satellite, wherein: A communication system comprising: a camera that captures an observation image; and a multiplexing unit that multiplexes a signal captured by the camera and a reception signal from the ground station. 2. The satellite has driving means for changing the direction of the camera, and the ground station has control means for generating a control signal for controlling the direction of the camera. The communication system according to claim 1, wherein the direction of the camera can be changed on the ground station side. 3. The communication system according to claim 2, wherein the control means is connected to an external control means via a computer network, and the direction of the camera can be changed by operating the external control means. 4. The communication system according to claim 1, wherein said multiplexing means frequency-division multiplexes a signal photographed by said camera and a signal received from said ground station. 5. The communication system according to claim 1, wherein said multiplexing means multiplexes a signal photographed by said camera and a signal received from said ground station. 6. The communication system according to claim 1, wherein said multiplexing means code-division-multiplexes a signal photographed by said camera and a signal received from said ground station. 7. A receiving apparatus for receiving a video signal transmitted from a ground station via a satellite, wherein the satellite is provided with a camera for photographing an observation image from the satellite, and the camera is connected to the satellite by the camera. A photographed signal and a reception signal from the ground station are multiplexed and transmitted, and storage means for storing a signal photographed by the camera, and screen processing for processing a screen stored in the storage means And a receiving device. 8. The receiving apparatus according to claim 7, wherein said screen processing means forms a plurality of screens. 9. The receiving apparatus according to claim 7, wherein said screen processing means cuts out a predetermined area from a screen stored in said storage means and can change said cutout position. 10. The receiving apparatus according to claim 7, wherein said screen processing means can read the screen stored in said storage means by enlarging or reducing it.