Satellite system, data relay equipment, data relay method, and program

Abstract

To provide a satellite system capable of easily and stably repeating data.SOLUTION: A satellite system comprises a first satellite control system 102 which communicates with a first satellite 101 and a second satellite control system 202 which communicates with a second satellite 201. The first satellite control system 102 transmits first command data 110 having commands for operating the first satellite and information related to the first satellite to the second satellite control system 202. The second satellite control system 202 generates second command data 210 having the information, related to the first satellite, imparted to the first command data 110 as a header that the second satellite 201 can read, and transmits the second command data 210 to the second satellite 201. The second satellite 201 having received the second command data 210 transfers the first command data 110 to the first satellite 101 based upon the header.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a satellite system, a data relay device, a data relay method, and a program.

Background Art

[0002] Patent Document 1 discloses a data relay method for performing data transfer between a ground station and an observation satellite via a data relay satellite.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When performing high-capacity data communication between the ground and a satellite, centimeter waves with a frequency of about 9 GHz and a wavelength of about 33 mm, called the X-band, are often used.

[0005] Since the radio waves in the X-band have high directivity, high-speed data communication can be performed. However, since the beam width becomes narrow, high-precision tracking, antenna control, and a large-scale transmission / reception antenna are required. In addition, in a communication system using radio waves with a high frequency and a short wavelength such as the X-band, it is easily affected by the atmosphere, and rain attenuation is significant.

[0006] In addition, since the radio waves in the X-band have high directivity and are weak against obstacles, data communication between the ground and a satellite is performed in a state where the satellite is visible from the ground station antenna.

[0007] In recent years, the number of satellites orbiting the Earth has been increasing, and satellite constellations, involving thousands of satellites launched and coordinated to orbit the Earth, are being planned and executed. In satellite systems like satellite constellations, which aim to accomplish a single mission in coordination with other satellites, real-time data distribution is crucial.

[0008] In such satellite systems, distributing data to all satellites presents challenges, such as the need to complete distribution only after all satellites are visible, or the requirement to install and operate ground station antennas at every point on Earth.

[0009] Patent Document 1 discloses a data relay method for transferring data between a ground station antenna and an observation satellite via a data relay satellite. However, the data relay satellite disclosed in Patent Document 1 is a satellite dedicated to data relay, and it was necessary to manage and control its orbit and orbit, which differed from that of other observation satellites.

[0010] Furthermore, if the data format differs between the data relay satellite and the observation satellite during data transfer, the interface will need to be modified. In addition, in the event of a failure in the satellite system, particularly the data relay satellite, means of recovery or redundancy will be necessary.

[0011] This disclosure was made in consideration of these challenges and aims to provide a satellite system that can perform data relay simply and stably. [Means for solving the problem]

[0012] The satellite system according to this disclosure comprises a first satellite control system that communicates with a first satellite and a second satellite control system that communicates with a second satellite. The first satellite control system transmits first command data having commands to operate the first satellite and information relating to the first satellite to the second satellite control system. The second satellite control system generates second command data by adding information relating to the first satellite as a header readable by the second satellite to the first command data, transmits the second command data to the second satellite, and the second satellite, upon receiving the second command data, forwards the first command data to the first satellite based on the header.

[0013] The data relay device according to this disclosure is a data relay device that transfers command data to a first satellite via a second satellite, and comprises a data receiving unit that receives the command data from a satellite control system that controls the first satellite, a data generating unit that generates data in which information relating to the first satellite is attached to the command data as a header readable by the second satellite, and a data transmitting unit that transmits the data to the second satellite.

[0014] The data relay method relating to this disclosure is a data relay method for transferring command data to a first satellite via a second satellite, the method comprising: receiving the command data from a satellite control system controlling the first satellite; generating data by adding information about the first satellite as a header readable by the second satellite to the command data; and transmitting the data to the second satellite.

[0015] The program relating to this disclosure is a program for transferring command data to a first satellite via a second satellite, and causes a computer to receive the command data from a satellite control system that controls the first satellite, generate data in which information about the first satellite is attached to the command data as a header readable by the second satellite, and transmit the data to the second satellite. [Effects of the Invention]

[0016] According to the present disclosure, a satellite system capable of simply and stably performing data relay can be provided.

Brief Description of the Drawings

[0017] [Figure 1] It is an explanatory diagram of the satellite system according to Embodiment 1. [Figure 2] It is a flowchart of the operation in the satellite system according to Embodiment 1. [Figure 3] It is a flowchart of the process in the first satellite control system according to Embodiment 2. [Figure 4] It is a schematic diagram of the data relay device according to Embodiment 3. <000007​​​​​​​​​​​​​​​​​​​​The second satellite control system 202 processes the information regarding the first satellite included in the first satellite header 112 into a second satellite header 212 that can be read by the second satellite 201. The second satellite control system 202 attaches the second satellite header 212 to the first command data 110 to generate second command data 210 for the second satellite 201. Thereafter, the second satellite control system 202 transmits the second command data 210 to the ground station antenna 301, and causes the ground station antenna 301 to transmit the second command data 210 to the second satellite 201 (S12).

[0022] The second satellite 201 interprets the second satellite header 212 (S13), and determines whether the received command data is for the second satellite 201 itself or for another satellite (S14). To interpret can be paraphrased as to read.

[0023] If the interpreted command data is command data for the second satellite 201, the second satellite 201 interprets the command data and executes the command at the specified time based on the command data (S15). Command data for the second satellite 201 is command data targeted at the second satellite 201.

[0024] If the interpreted command data is command data for the first satellite 101, the command data is transferred to the first satellite 101 (S16). Command data for the first satellite 101 is command data targeted at the first satellite 101.

[0025] The first satellite 101 interprets the received command data (S17) and executes the command at the specified time based on the command data (S18).

[0026] In this way, the satellite system according to this embodiment can transmit command data to the first satellite via the second satellite.

[0027] <Embodiment 2> In this embodiment, the satellite system according to Embodiment 1 will be described in detail.

[0028] The first satellite control system 102 controls or manages the orbit of the first satellite 101. The second satellite control system 202 controls or manages the orbit of the second satellite 201.

[0029] The ground station antenna 301 is used when the first satellite control system 102 transmits data to the first satellite 101 and when the second satellite control system 202 transmits data to the second satellite 201. Alternatively, the first satellite control system 102 and the second satellite control system 202 may each be equipped with a transmitting and receiving antenna. In this case, the first satellite control system 102 transmits data to the first satellite 101 using its transmitting and receiving antenna, and the second satellite control system 202 transmits data to the second satellite 201 using its transmitting and receiving antenna.

[0030] When performing high-capacity data communication, the ground station antenna 301 uses high-frequency, short-wavelength radio waves such as the X-band. On the other hand, when performing relatively low-capacity data communication, it is also possible to use radio waves such as the S-band, which have lower frequencies and longer wavelengths compared to the X-band.

[0031] For example, the S-band is a centimeter wave with a frequency of around 3 GHz and a wavelength of around 100 mm. Compared to the X-band, it is less affected by the atmosphere and can be controlled with simple transmitting and receiving antennas. Therefore, by using low-frequency bands such as the S-band, although the communication capacity and speed are inferior to the X-band, communication constraints such as antenna control accuracy and rain attenuation are less severe, enabling stable communication.

[0032] Furthermore, when transferring data from the second satellite 201 to the first satellite 101, it is not necessary to consider atmospheric effects, so the X-band, which offers superior communication capacity and speed, may be used.

[0033] The first satellite control system 102 creates the first command data 110 when it transmits command data directly to the first satellite 101, that is, when the first satellite 101 is visible from the ground station antenna 301.

[0034] Therefore, in the satellite system according to this embodiment, the command data received by the first satellite 101 is the same whether the first satellite 101 is visible from the ground station antenna 301 or not. When the first satellite 101 is visible from the ground station antenna 301, the first satellite 101 receives the command data via the ground station antenna 301. When the first satellite 101 is not visible from the ground station antenna 301, the first satellite 101 receives the command data via the second satellite. As a result, the command data received by the first satellite 101 is in the same format as when it is received directly from the ground station antenna 301, so no change to the interface is necessary.

[0035] Here, the processing of the first satellite control system 102 in the cases where the first satellite 101 is visible from the ground station antenna 301 and when it is not visible will be explained using the flowchart shown in Figure 3.

[0036] First, the first satellite control system 102 checks the positional relationship between the ground station antenna 301 and the first satellite 101 (S21). The method of checking may be, for example, to periodically transmit data to the first satellite 101 and determine whether or not a response can be received to determine whether or not the first satellite 101 is in a position visible from the ground station antenna 301. Alternatively, the positional relationship may be determined from the coordinate information of the first satellite 101.

[0037] Next, it is determined whether the first satellite 101 is visible from the ground station antenna 301 (S22). If the first satellite 101 is visible, the first satellite control system 102 creates the first command data 110 (S23) and transmits the first command data 110 directly to the first satellite 101 via the ground station antenna 301 (S24).

[0038] If the first satellite 101 is invisible, the first satellite control system 102 creates the first command data 110 (S25) and transmits the first command data 110 to the second satellite control system 202 (S26). The subsequent processing is the same as from S12 onwards in Figure 2, so it is omitted.

[0039] The information regarding the first satellite 101 included in the first satellite header 112 includes, for example, the satellite identifier, the satellite's orbit and coordinates, and communication parameters with the satellite.

[0040] The second satellite control system 202 generates the second command data 210 by adding the second satellite header 212, obtained by processing the first satellite header 112, to the first command data 110. For example, the second satellite control system 202 processes the first satellite header into a second satellite header 212 that is in a format that the second satellite 201 can interpret. In other words, the second satellite control system 202 converts the first satellite header into a second satellite header 212 that is in a format that the second satellite 201 can interpret. Specifically, the second satellite control system 202 may set information about the first satellite 101 into the second satellite header 212 that is in a format that the second satellite 201 can interpret, and then add the second satellite header to the first command data.

[0041] Alternatively, the data may be stored in an existing header section, such as the header for the first satellite 112, without adding the header for the second satellite 212. For example, the second satellite 201 may be able to interpret a specific area in the header for the first satellite 112, and information regarding the first satellite 101 may be stored in an area that the second satellite 201 can interpret.

[0042] The first satellite control system 102 does not need to store information other than the satellite identifier, such as the satellite's orbit and coordinates, and communication parameters with the satellite, within the first command data 110, which is included in the first satellite header 112. Furthermore, the second satellite control system 202 may set or store at least the satellite identifier, among the information related to the first satellite 101, in the second satellite header 212. For example, information other than the satellite identifier, such as the satellite's orbit and coordinates, and communication parameters with the satellite, may be associated and managed for each satellite in a database constructed within the satellite constellation. In this case, the second satellite 201 can obtain information about the first satellite 101 by querying the database using the satellite identifier of the first satellite 101 obtained from the second command data 210.

[0043] The ground station antenna 301 transmits the second command data 210 received from the second satellite control system 202 to the second satellite 201. At this time, the second command data 210 may be transmitted in the frequency band used for satellite control operations of the second satellite 201.

[0044] For example, by using the S-band, which is a lower frequency and longer wavelength radio wave than the X-band, the second satellite 201 does not need to be equipped with equipment that is required for satellites dedicated to data relay, namely antennas that transmit and receive X-band radio waves, thus reducing costs. In addition, even if the second satellite 201 is not a satellite dedicated to data relay, if it is equipped with antennas that transmit and receive S-band radio waves, it will be able to receive command data intended for other satellites.

[0045] Furthermore, data relay may be repeated multiple times, passing through one or more other relay satellites before reaching the first satellite 101. For example, in data relay from the second satellite 201 to the first satellite 101, a third satellite (not shown) may be passed between these satellites.

[0046] At this time, the second satellite control system 202 may specify all the relay satellites to be traversed. Alternatively, it may specify only the final relay destination satellite (the first satellite 101 in this embodiment), and use the relay satellite's stored information on other relayable satellites to determine the next relay destination and perform data relay.

[0047] Furthermore, there may be more than one relay satellite. For example, data may be distributed to multiple other relay satellites in the satellite constellation to which the first satellite 101 belongs. In this case, the relay data may include flag information to determine whether or not it has been received.

[0048] Furthermore, if a relay satellite (the second satellite 201 in this embodiment) experiences a failure, data relay may be performed by a satellite outside the satellite constellation to which the failed relay satellite belongs. By using the data relay method of this embodiment, a header that can be read by relay satellites belonging to different satellite constellations can be added, making data relay easier. Therefore, the satellite system according to this embodiment can be made redundant. <Embodiment 3>

[0049] This embodiment describes the internal structure of the data relay device in the satellite system according to Embodiments 1 and 2. Figure 4 is a configuration diagram of the data relay device according to this embodiment. The data relay device is installed inside the second satellite control system 202 and comprises a data receiving unit 401, a data generation unit 402, and a data transmission unit 403.

[0050] The data receiving unit 401 receives the first command data 110 transmitted from the first satellite control system 102.

[0051] The data generation unit 402 processes the information about the first satellite 101 contained in the received first command data 110 into a second satellite header 212 that can be read by the second satellite 201. Then, it adds the second satellite header 212 to the first command data 110 to generate the second command data 210 for the second satellite 201.

[0052] The data transmission unit 403 transmits the second command data 210 to the ground station antenna 301, causing the ground station antenna 301 to transmit the second command data 210 to the second satellite 201. Subsequently, the second satellite 201, having received the second command data 210, forwards the first command data 110 to the first satellite 101.

[0053] Thus, the data relay device according to this embodiment can provide a satellite system that transfers command data to the first satellite via the second satellite.

[0054] In the examples described above, the program includes a set of instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more of the functions described in the embodiments. The program may be stored on a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include temporary computer-readable medium or a communication medium that includes electrically, optically, acoustically or otherwise propagating signals.

[0055] This disclosure is not limited to the embodiments described above, and can be modified as appropriate without departing from its spirit. The first satellite 101 and the second satellite 201 are described as belonging to the same satellite constellation operating the satellite system of this disclosure, but are not limited thereto. For example, a satellite that needs to transmit command data but is not visible from the ground station antenna 301 may be referred to as the first satellite 101, and a satellite that is visible from the ground station antenna 301 and is in a position to communicate with the first satellite 101 may be referred to as the second satellite 201. By using the data relay method of this disclosure, command data can be reliably relayed even if the first satellite 101 and the second satellite 201 belong to different satellite constellations. [Explanation of symbols]

[0056] 101 1st satellite 102 First Satellite Control System 110 First command data 111 Data for the first satellite 112 Header for the first satellite 201 2nd satellite 202 Second Satellite Control System 210 Second command data 212 Header for the second satellite 301 Ground station antenna 401 Data Receiving Unit 402 Data Generation Unit 403 Data Transmission Unit

Claims

1. The first satellite control system communicates with the first satellite, It is equipped with a second satellite control system that communicates with the second satellite, The first satellite control system transmits first command data having commands to operate the first satellite and information relating to the first satellite to the second satellite control system. The second satellite control system generates second command data by adding information about the first satellite as a header readable by the second satellite to the first command data, and transmits the second command data to the second satellite. Upon receiving the second command data, the second satellite forwards the first command data to the first satellite based on the header. Satellite system.

2. When the second satellite control system transmits the second command data to the second satellite, it uses the frequency band used for the satellite control operations of the second satellite. The aforementioned frequency band is in a lower frequency range than the frequency band used for communication between the second satellite and the first satellite. The satellite system according to claim 1.

3. Furthermore, it is equipped with a ground station antenna, When the first satellite is invisible from the ground station antenna, the first satellite control system transmits the first command data to the second satellite control system. The satellite system according to claim 1 or 2.

4. The first command data has a header section that stores information about the first satellite, The header generated by the second satellite control system is stored in the header section. The satellite system according to claim 1 or 2.

5. The transfer of the first command data from the second satellite to the first satellite is carried out via a third satellite located between the second satellite and the first satellite. The satellite system according to claim 1 or 2.

6. A data relay device that transmits command data to the first satellite via the second satellite, A data receiving unit that receives the command data from the satellite control system that controls the first satellite, A data generation unit that generates data in which information relating to the first satellite is added to the command data as a header readable by the second satellite, The system includes a data transmission unit that transmits the aforementioned data to the second satellite, Data relay device.

7. When the data transmission unit transmits the data to the second satellite, it uses the frequency band used for the satellite control operations of the second satellite. The aforementioned frequency band is in a lower frequency range than the frequency band used for communication between the second satellite and the first satellite. The data relay device according to claim 6.

8. A data relay method for transferring command data to a first satellite via a second satellite, The command data is received from the satellite control system that controls the first satellite. Data is generated in which information about the first satellite is added to the command data as a header that can be read by the second satellite. The data is transmitted to the second satellite. Data relay method.

9. When transmitting the aforementioned data to the second satellite, the frequency band used for the satellite control operations of the second satellite shall be used. The aforementioned frequency band is in a lower frequency range than the frequency band used for communication between the second satellite and the first satellite. The data relay method according to claim 8.

10. A program that transfers command data to the first satellite via the second satellite, The command data is received from the satellite control system that controls the first satellite. Data is generated in which information about the first satellite is added to the command data as a header that can be read by the second satellite. The computer is instructed to transmit the aforementioned data to the second satellite. program.

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