Space communication system, space communication device, space communication method, and space communication program
Patent Information
- Application Number
- PCT/JP2026/005274
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-25
- Filing Date
- 2026-02-13
- Publication Date
- 2026-09-03
Smart Images
Figure JP2026005274_03092026_PF_FP_ABST
Abstract
Description
Space communication system, space communication apparatus, space communication method and space communication program
[0001] The present disclosure relates to a space communication system, a space communication apparatus, a space communication method and a space communication program. This application claims priority based on Japanese Patent Application No. 2025-27574 filed on February 25, 2025, and the entire disclosure thereof is incorporated herein.
[0002] For example, spacecraft communicate with other spacecraft and the like by using the Space Packet Protocol, for which standardization work was carried out at the Consultative Committee for Space Data Systems, described in SPACE PACKET PROTOCOL, June 2020, [online], CCSDS, [retrieved February 25, 2025], Internet, <URL:https: / / public.ccsds.org / Pubs / 133x0b2e2.pdf> (Non-Patent Document 1), as an end-to-end protocol for space communication. For example, between spacecraft, and between spacecraft and ground stations, data is transmitted and received using space packets conforming to the Space Packet Protocol.
[0003] SPACE PACKET PROTOCOL, June 2020, [online], CCSDS, [retrieved February 25, 2025], Internet, <URL:https: / / public.ccsds.org / Pubs / 133x0b2e2.pdf>
[0004] The space communication system of the present disclosure includes a first space communication apparatus and a second space communication apparatus, the first space communication apparatus acquires a first packet conforming to a first standard used in space communication, the first space communication apparatus stores divided data obtained by dividing data included in the acquired first packet into a frame conforming to a second standard that is a CAN or CAN FD standard and transmits the frame to the second space communication apparatus, and the second space communication apparatus combines a plurality of pieces of the divided data respectively included in the plurality of frames received from the first space communication apparatus to restore the data.
[0005] One aspect of this disclosure can be realized not only as a space communication system equipped with such characteristic processing units, but also as a semiconductor integrated circuit that realizes part or all of the space communication system.
[0006] Figure 1 is a diagram showing an example of the configuration of a space communication system according to an embodiment of the present disclosure. Figure 2 is a diagram showing an example of the configuration of a spacecraft according to an embodiment of the present disclosure. Figure 3 is a diagram showing an example of the configuration of a space communication device according to an embodiment of the present disclosure. Figure 4 is a diagram showing an example of a CAN-MA packet transmitted by a space communication device according to an embodiment of the present disclosure. Figure 5 is a diagram for explaining the frame creation process by a space communication device according to an embodiment of the present disclosure. Figure 6 is a diagram showing an example of a CAN frame transmitted by a space communication device according to an embodiment of the present disclosure. Figure 7 is a diagram showing an example of the format of the DAT field in a CAN frame transmitted by a data transmission device according to an embodiment of the present disclosure. Figure 8 is a diagram showing another example of the configuration of a space communication device according to an embodiment of the present disclosure. Figure 9 is a flowchart defining an example of the operation procedure when a data transmission device according to an embodiment of the present disclosure performs the process of transmitting a CAN frame. Figure 10 is a flowchart defining an example of the operation procedure when a data transmission device according to an embodiment of the present disclosure performs the process of transmitting a CAN frame. Figure 11 is a flowchart defining an example of the operation procedure when a data receiving device according to an embodiment of the present disclosure performs the restoration process. Figure 12 is a flowchart showing an example of the operation procedure when a data receiving device according to an embodiment of this disclosure performs restoration processing. Figure 13 is a diagram showing an example of the processing sequence of a data transmitting device and a data receiving device in a space communication system according to an embodiment of this disclosure. Figure 14 is a diagram for explaining the priority set for commands and replies transmitted and received by Modification 1 of the space communication device according to an embodiment of this disclosure. Figure 15 is a diagram showing an example of the format of the DAT field in a CAN frame transmitted by Modification 2 of the data transmitting device according to an embodiment of this disclosure. Figure 16 is a diagram showing an example of the format of the DAT field in a CAN frame transmitted by Modification 3 of the data transmitting device according to an embodiment of this disclosure. Figure 17 is a diagram showing an example of the format of the DAT field in a CAN frame transmitted by Modification 3 of the data transmitting device according to an embodiment of this disclosure.Figure 18 shows an example of the format of the DAT field in a CAN frame transmitted by Modification 3 of the data transmission device according to the embodiment of the present disclosure.
[0007] Spacecraft such as artificial satellites communicate with other spacecraft in accordance with standards set by organizations such as the Consultative Committee for Space Data Systems (CCSDS).
[0008] [Issues this disclosure aims to solve] There are no standard communication standards defined for onboard subnetworks such as networks within spacecraft. For example, the Space Data Systems Advisory Committee recommends adopting standards such as MIL-STD-1553B, SpaceWire, Wireless, and CAN (Controller Area Network) as communication standards for onboard subnetworks.
[0009] In the future, if spacecraft are mass-produced, CAN or CAN FD (CAN with Flexible Data-Rate), which are used in mass-produced vehicles and other products, may be adopted as the communication standard for onboard subnetworks.
[0010] Here, the maximum data length of a space packet is 65,542 bytes. On the other hand, the maximum data length of a data field in a frame conforming to the CAN standard is 8 bytes. Therefore, a technology capable of processing data contained in space packets is desired in onboard subnetworks conforming to the CAN or CAN FD standard.
[0011] This disclosure was made to solve the above-mentioned problems, and its purpose is to provide a space communication system, space communication device, space communication method, and space communication program that can process data contained in packets conforming to space communication standards in a network conforming to CAN or CAN FD standards.
[0012] [Effects of this Disclosure] According to this disclosure, data contained in packets conforming to space communications standards can be processed in a network conforming to CAN or CAN FD standards.
[0013] [Description of Embodiments of the Disclosure] First, the contents of embodiments of the Disclosure will be listed and described. (1) The space communication system according to an embodiment of the Disclosure comprises a first space communication device and a second space communication device, wherein the first space communication device acquires a first packet in accordance with a first standard used in space communication, the first space communication device stores the divided data obtained by dividing the data contained in the acquired first packet into a frame in accordance with a second standard which is a standard for CAN or CAN FD and transmits it to the second space communication device, and the second space communication device combines the plurality of divided data contained in each of the plurality of frames received from the first space communication device to restore the data.
[0014] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by configuring the system to divide the data contained in the packet, store the divided data in the frame, and transmit it, the data can be transmitted more reliably to the space communication equipment of the communication partner. Furthermore, by configuring the space communication equipment that receives the frame to combine the multiple divided data contained in each of the received frames to reconstruct the data, various processing can be performed using the reconstructed data. Therefore, data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.
[0015] (2) In the above (1), the first space communication device may create a second packet which includes a header indicating the type of data, the data, and a CRC code, and which conforms to a third standard different from the first standard and the second standard, and the first space communication device may divide the created second packet and store it in the frame.
[0016] With this configuration, the space communication equipment receiving the frame can determine the type of data contained in the frame and perform error detection on the data using a CRC code.
[0017] (3) In (1) or (2) above, the first space communication device may create a second packet which includes the data and conforms to a third standard which is different from the first and second standards, and the second packet may further include information indicating that it requests the writing of the data to the memory of the second space communication device, or information indicating that it has read the data requested by the second space communication device from the memory of the first space communication device, and the first space communication device may divide the created second packet and store it in the frame.
[0018] This configuration makes it easy for the space communication equipment at the destination of the frame to understand what needs to be done with the recovered data.
[0019] (4) In any of (1) to (3) above, the first space communication device may transmit to the second space communication device a frame containing data which is divided data that is different from the data contained in the first packet, in addition to the divided data.
[0020] This configuration allows for the efficient transmission of various types of data in a network conforming to the CAN or CAN FD standard, by mixing data contained in packets conforming to space communication standards with other data.
[0021] (5) In (2) or (3) above, the first space communication device may further acquire a third packet which is a fourth standard used in space communications and conforms to a fourth standard different from the first standard, and the first space communication device may create a second packet which further includes the data contained in the third packet in addition to the data contained in the first packet.
[0022] This configuration allows for the transmission of multiple types of data corresponding to various space communication standards, enabling efficient transmission of multiple data types that support space communication standards.
[0023] (6) The space communication device according to the embodiment of the present disclosure includes an acquisition unit that acquires packets in accordance with a first standard used in space communication, a creation unit that creates a frame in accordance with a second standard which is a standard for CAN or CAN FD, and which includes divided data obtained by dividing the data contained in the packets acquired by the acquisition unit, and which transmits the frame created by the creation unit to another device.
[0024] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by configuring the system to divide the data contained in the packet, store the divided data in the frame, and transmit it, the data can be transmitted more reliably to the space communication equipment of the communication partner. Therefore, the data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.
[0025] (7) The space communication device according to the embodiment of the present disclosure is a space communication device used in a space communication system, comprising: a receiving unit that receives from another space communication device a frame that conforms to the CAN or CAN FD standard and stores divided data obtained by dividing data contained in a packet used in space communication; and a restoring unit that restores the data by combining a plurality of divided data contained in each of the plurality of frames received by the receiving unit.
[0026] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by receiving a frame containing segmented data obtained by dividing the data contained in the packet, and combining the segmented data contained in each of the received frames to reconstruct the data, various processing can be performed using the reconstructed data. Therefore, data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.
[0027] (8) An embodiment of the space communication method according to the present disclosure is a space communication method in a space communication system comprising a first space communication device and a second space communication device, the first space communication device acquiring a first packet in accordance with a first standard used in space communication; the first space communication device storing divided data, which is obtained by dividing the data contained in the acquired first packet, into a frame in accordance with a second standard which is a standard for CAN or CAN FD, and transmitting it to the second space communication device; and the second space communication device combining a plurality of divided data contained in a plurality of frames received from the first space communication device to restore the data.
[0028] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by dividing the data contained in the packet and storing the divided data in the frame before transmission, the data can be transmitted more reliably to the space communication equipment of the communication partner. Furthermore, at the space communication equipment to which the frame was transmitted, various processing can be performed using the reconstructed data by combining the multiple divided data contained in each of the received frames. Therefore, data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.
[0029] (9) The space communication program according to the embodiment of the present disclosure is a space communication program used in a space communication device, which causes a computer to function as an acquisition unit that acquires packets in accordance with a first standard used in space communication, and a transmission unit that stores the divided data obtained from the packets acquired by the acquisition unit into frames in accordance with a second standard which is a standard for CAN or CAN FD, and transmits them to another device.
[0030] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by configuring the system to divide the data contained in the packet, store the divided data in the frame, and transmit it, the data can be transmitted more reliably to the space communication equipment of the communication partner. Therefore, the data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.
[0031] (10) The space communication program according to the embodiment of the present disclosure is a space communication program used in a space communication device used in a space communication system, and is a program that causes a computer to function as a receiving unit that receives frames in which data included in packets used in space communication has been divided, in accordance with the CAN or CAN FD standard, from another space communication device, and a restoration unit that combines a plurality of the divided data included in each of the plurality of frames received by the receiving unit to restore the data.
[0032] The data length of a packet conforming to space communication standards is greater than the data length of a data field in a frame conforming to CAN or CAN FD standards. As described above, by receiving a frame containing segmented data obtained by dividing the data contained in the packet, and combining the segmented data contained in each of the received frames to reconstruct the data, various processing can be performed using the reconstructed data. Therefore, data contained in a packet conforming to space communication standards can be processed in a network conforming to CAN or CAN FD standards.
[0033] Embodiments of this disclosure will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any way.
[0034] [Space Communication System] Figure 1 is a diagram showing an example of the configuration of a space communication system according to an embodiment of the present disclosure. Referring to Figure 1, the space communication system 501 comprises, for example, a plurality of spacecraft 301.
[0035] In the example shown in Figure 1, the space communication system 501 comprises multiple spacecraft 301, namely spacecraft 301A and 301B. The spacecraft 301A and 301B are artificial satellites, space probes, and space shuttles, etc.
[0036] Furthermore, the space communication system 501 is not limited to a configuration comprising two spacecraft 301, but may also be configured to comprise three or more spacecraft 301. Also, the space communication system 501 is not limited to a configuration comprising multiple spacecraft 301, but may also be configured to comprise one spacecraft 301.
[0037] [Spacecraft] Figure 2 is a diagram showing an example of the configuration of a spacecraft according to an embodiment of the present disclosure. Figure 2 shows the configuration of spacecraft 301A.
[0038] Referring to Figure 2, the spacecraft 301A is equipped with multiple space communication devices 101. In the example shown in Figure 2, the spacecraft 301 is equipped with multiple space communication devices 101, namely space communication devices 101A, 101B, and 101C.
[0039] The space communication apparatuses 101B and 101C are connected to the space communication apparatus 101A via, for example, a CAN bus 51. The space communication apparatuses 101A, 101B, and 101C constitute an on-board subnetwork 401, which is a network inside the spacecraft 301A. CAN is an example of the second standard.
[0040] Note that the number of space communication apparatuses 101 connected to the CAN bus 51 is not limited to two, and may be three or more.
[0041] Information is transmitted and received between the space communication apparatuses 101 in accordance with the CAN standard. Specifically, a space communication apparatus 101 transmits a CAN frame including various types of information to another space communication apparatus 101.
[0042] For example, the space communication apparatus 101A transmits various types of data such as observation data indicating observation results of an object in outer space to the space communication apparatuses 101B and 101C. Hereinafter, the space communication apparatus 101A is also referred to as a data transmitting apparatus.
[0043] The space communication apparatuses 101B and 101C perform predetermined processing using various data received from the space communication apparatus 101A. Hereinafter, each of the space communication apparatuses 101B and 101C is also referred to as a data receiving apparatus.
[0044] [Data Transmitting Apparatus] FIG. 3 is a diagram showing an example of the configuration of a space communication apparatus according to an embodiment of the present disclosure. FIG. 3 shows the configuration of the space communication apparatus 101A, that is, the data transmitting apparatus.
[0045] Referring to FIG. 3, the data transmitting apparatus includes an observation unit 11, a space packet acquisition unit 12, a CAN-MA (CAN-Memory Access) packet creation unit 13, a CAN frame creation unit 14, a communication unit 15, and a storage unit 16. Part or all of the observation unit 11, the space packet acquisition unit 12, the CAN-MA packet creation unit 13, the CAN frame creation unit 14, and the communication unit 15 are realized by, for example, one or a plurality of processing circuits. The storage unit 16 is a non-volatile memory included in the processing circuit. The communication unit 15 is an example of a transmitting unit.
[0046] (Observation Unit) For example, the observation unit 11 performs observation processing for observing an object in outer space. Said object includes space debris, and other spacecraft 301 that is different from the spacecraft 301 on which the data transmission device of the present disclosure is mounted, etc.
[0047] The observation unit 11 performs observation processing periodically or irregularly, for example. Each time the observation unit 11 performs observation processing, it saves observation data indicating an observation result in the storage unit 16.
[0048] (Space Packet) A space packet acquisition unit 12 acquires a space packet P1 that conforms to the space packet protocol used in space communication. The space packet protocol is an example of a first standard, and the space packet P1 is an example of a first packet.
[0049] The space packet protocol is a communication protocol for space communication that has undergone standardization work at the Consultative Committee for Space Data Systems (CCSDS). The space packet protocol is a network layer protocol in the OSI reference model.
[0050] As processing for acquiring the space packet P1, the space packet acquisition unit 12 performs, for example, creation processing for generating the space packet P1.
[0051] Specifically, for example, the space packet acquisition unit 12 performs creation processing C1 for generating a space packet P1 (hereinafter also referred to as "space packet P11") including observation data for writing to a storage unit 24 (hereinafter also referred to as "Write processing") described later in a data receiving device.
[0052] Further, for example, the space packet acquisition unit 12 performs creation processing C2 for generating a space packet P1 (hereinafter also referred to as "space packet P12") including observation data requested by the data receiving device.
[0053] Space packet P1 has a data field. The data length of the data field is, for example, in the range of 1 byte to 65,536 bytes. For example, observation data is stored in the data field of space packet P1.
[0054] (a1) Creation of space packet P11 For example, when the processing timing T of the creation process C1 arrives, the space packet acquisition unit 12 retrieves multiple observation data stored in the storage unit 16 by the observation unit 11 during the period from the previous processing timing T to the current processing timing T.
[0055] Then, the space packet acquisition unit 12 creates a space packet P11 containing the multiple observation data that have been extracted.
[0056] The space packet acquisition unit 12 outputs the created space packet P11 to the CAN-MA packet creation unit 13, and also outputs data information B1 to the CAN-MA packet creation unit 13 indicating that the multiple observation data contained in the space packet P11 are data for write processing.
[0057] (a2) Creation of space packet P12 The data receiving device shown in Figure 2 holds, for example, an address table Tb2 that indicates the addresses of the observed data stored in the storage unit 16 of the data transmitting device.
[0058] The data receiving device uses its stored address table Tb2 to confirm the address in the storage unit 16 of the observed data that it requests the data transmitting device to transmit. Alternatively, the data receiving device may be configured to confirm the address in the storage unit 16 by a method other than the address table Tb2.
[0059] The data receiving device transmits data request information to the space communication device 101A, including the confirmed address, indicating a request to read out the observation data (hereinafter also referred to as "Read processing").
[0060] In the space communication device 101A, the communication unit 15 outputs data request information received from the space communication device 101B to the space packet acquisition unit 12.
[0061] The space packet acquisition unit 12 retrieves the observed data of the address indicated by the data request information received from the communication unit 15 from the storage unit 16.
[0062] Then, the space packet acquisition unit 12 creates a space packet P12 containing the extracted observation data.
[0063] The space packet acquisition unit 12 outputs the created space packet P12 to the CAN-MA packet creation unit 13, and also outputs data information B2 to the CAN-MA packet creation unit 13 indicating that the observed data contained in the space packet P12 is data corresponding to the Read processing requested by the data receiving device.
[0064] The space packet acquisition unit 12 may be configured to perform a process of acquiring space packets P1 from another spacecraft 301 different from the spacecraft 301A on which its own data transmission device is installed, instead of the creation processes C1 and C2 that create space packets P1.
[0065] Furthermore, the data stored in the data field of space packet P1 is not limited to observation data; it may also be other types of data, such as data related to health monitoring and data related to anomaly detection.
[0066] (Creation of CAN-MA packets) For example, the CAN-MA packet creation unit 13 creates a CAN-MA packet that contains data and conforms to the CAN-MA protocol. The CAN-MA packet is an example of a second packet. The CAN-MA protocol is an example of a third standard.
[0067] The CAN-MA protocol is a protocol that lies below the network layer and above the physical layer in the OSI reference model.
[0068] As an example, the CAN-MA packet creation unit 13 creates a CAN-MA packet containing observation data.
[0069] Figure 4 shows an example of a CAN-MA packet transmitted by a space communication device according to an embodiment of the present disclosure.
[0070] Referring to Figure 4, for example, a CAN-MA packet has a header Ha, a data field Da, and a CRC (Cyclic Redundancy Check) code. Specifically, a CAN-MA packet has the header Ha, the data field Da, and the CRC code in this order from the beginning of the packet.
[0071] In a CAN-MA packet, the header Ha indicates the type of data stored in the data field Da. Specifically, for example, the MSB (Most Significant Bit) of header Ha is flag F1, and the second bit from the MSB is flag F2.
[0072] Flag F1 indicates whether the data stored in data field Da corresponds to a Write operation or a Read operation. For example, if the data stored in data field Da corresponds to a Write operation, the value of flag F1 is set to "1". On the other hand, if the data stored in data field Da corresponds to a Read operation, the value of flag F1 is set to "zero".
[0073] Flag F2 indicates whether the data stored in the data field Da is data included in the request packet or data included in the response packet. A request packet is a CAN-MA packet containing information (hereinafter also referred to as a "command") indicating a request for the execution of a Write or Read process. A response packet is a CAN-MA packet containing information (hereinafter also referred to as a "reply") indicating that a Write or Read process has been executed. For example, if the CAN-MA packet is a request packet, the value of flag F2 is set to "1". On the other hand, if the CAN-MA packet is a response packet, the value of flag F2 is set to "zero".
[0074] In the following explanation, the space communication device 101 that sends commands will also be referred to as the controller node, and the space communication device 101 that sends replies will also be referred to as the responder node.
[0075] The data length of data field Da ranges from 7 bytes to 65542 bytes. In other words, the data length of data field Da is the same as the data length of space packet P1.
[0076] The CRC code is used in data receiving devices to detect errors in the header Ha and data field Da of CAN-MA packets.
[0077] When the CAN-MA packet creation unit 13 receives a space packet P1 from the space packet acquisition unit 12, it creates a CAN-MA packet.
[0078] Specifically, for example, when the CAN-MA packet creation unit 13 receives a space packet P11 and data information B1 from the space packet acquisition unit 12, it determines to create a CAN-MA packet related to the Write process.
[0079] For example, the storage unit 16 stores a usage status table Tb1 that shows the data writing status in the storage unit 24 of the data receiving device, which will be described later.
[0080] When the CAN-MA packet creation unit 13 determines that it will create a CAN-MA packet related to the Write process, it refers to the usage table Tb1 in the storage unit 16 to confirm addresses to which data has not been written (hereinafter also referred to as "free addresses").
[0081] When the CAN-MA packet creation unit 13 confirms an available address, it stores information indicating a request to execute a Write process (hereinafter also referred to as "write request information") and the available address in the header Ha, and creates a CAN-MA packet by storing the space packet P11 received from the space packet acquisition unit 12 in the data field Da. The CAN-MA packet creation unit 13 then sets the values of flags F1 and F2 in the header Ha of the CAN-MA packet to "1" and "1", respectively.
[0082] The memory unit 16 stores a predetermined generating polynomial used to calculate the CRC code. The CAN-MA packet creation unit 13 calculates the remainder by dividing the header Ha and data field Da of the created CAN-MA packet by the generating polynomial stored in the memory unit 16. The CAN-MA packet creation unit 13 then adds the calculated remainder as the CRC code to the created CAN-MA packet.
[0083] On the other hand, when the CAN-MA packet creation unit 13 receives the space packet P12 and data information B2 from the space packet acquisition unit 12, it decides to create a CAN-MA packet related to the Read process.
[0084] When the CAN-MA packet creation unit 13 determines that it is time to create a CAN-MA packet related to the Read process, it stores information indicating that it has read the observation data requested by the data receiving device from the storage unit 16 (hereinafter also referred to as "read completion information") in the header Ha, and creates a CAN-MA packet in which it stores the space packet P12 received from the space packet acquisition unit 12 in the data field Da. The CAN-MA packet creation unit 13 then sets the values of flags F1 and F2 in the header Ha of the CAN-MA packet to "zero" and "zero," respectively.
[0085] The CAN-MA packet creation unit 13 outputs a CAN-MA packet with a CRC code added to it to the CAN frame creation unit 14.
[0086] (Creation of CAN frame) Figure 5 is a diagram illustrating the frame creation process by a space communication device according to an embodiment of the present disclosure.
[0087] Referring to Figures 3 and 5, the CAN frame creation unit 14 performs frame creation processing to create a CAN frame that includes segmented data obtained by dividing the observed data contained in the space packet P1 acquired by the space packet acquisition unit 12, and that conforms to the CAN standard.
[0088] More specifically, for example, the CAN frame creation unit 14 stores the CAN-MA packets created by the CAN-MA packet creation unit 13 in a CAN frame.
[0089] Specifically, the CAN frame creation unit 14 divides the CAN-MA packet received from the CAN-MA packet creation unit 13 into multiple segmented packets. That is, the CAN frame creation unit 14 divides the space packet P1 stored in the data field Da of the CAN-MA packet.
[0090] Each segmented packet contains segmented data, which is obtained by dividing the space packet P1 stored in the data field Da, i.e., the observed data contained in space packet P1 is divided into segments.
[0091] Each segmented packet has a header Hb and a data field Db in which the segmented data is stored. For example, the length of the header Hb and the length of the data field Db are 2 bytes and 6 bytes, respectively.
[0092] The upper two bits of the header Hb indicate the position of the segmented data stored in the data field Db within the segmented packet.
[0093] Figure 6 shows an example of a CAN frame transmitted by a space communication device according to an embodiment of the present disclosure. Referring to Figure 6, the CAN frame has, in this order from the beginning of the frame, an SOF (Start Of Frame) field, an extension field, a CONTROL field, a data field (hereinafter also referred to as a DAT field), a CRC field, an ACK (Acknowledgement) field, and an EOF (End Of Frame) field.
[0094] Referring to Figures 3, 5, and 6, the CAN frame creation unit 14 divides the CAN-MA packet received from the CAN-MA packet creation unit 13 into multiple divided packets, and then creates a CAN frame containing each divided packet. The divided packets are stored, for example, in the DAT field of the CAN frame.
[0095] Figure 7 shows an example of the format of the DAT field in a CAN frame transmitted by a data transmission device according to an embodiment of the present disclosure.
[0096] In Figure 7, the vertical direction represents bytes, and the horizontal direction represents bits. The data length of the DAT field shown in Figure 7 is 8 bytes. The upper two bits of the "zero" byte in the DAT field represent the "Data Field Sequence". The "Data Field Sequence" indicates whether the CAN frame containing the DAT field is the first CAN frame, the last CAN frame, or another CAN frame other than the first and last CAN frames (hereinafter also referred to as an "intermediate frame") transmitted from the data transmission device.
[0097] Here, the "Data Field Sequence" value in the first CAN frame, the "Data Field Sequence" value in the last CAN frame, and the "Data Field Sequence" value in the intermediate frames are "1", "2", and "zero", respectively.
[0098] Furthermore, in the DAT field shown in Figure 7, the lower six bits of the "zero" byte and the "1" byte represent the "Data Field Count". The "Data Field Count" is a value that indicates which CAN frame the DAT field belongs to, as transmitted by the data transmission device. In the example shown in Figure 7, the "Data Field Count" is represented by 14 bits.
[0099] Furthermore, the segmented packets are stored in bytes 2 through 7 of the DAT field shown in Figure 7.
[0100] The CAN frame creation unit 14 sequentially outputs the multiple CAN frames it has created to the communication unit 15.
[0101] (Transmission of CAN frames) The communication unit 15 transmits multiple CAN frames created by the CAN frame creation unit 14 to the data receiving device.
[0102] More specifically, the communication unit 15 sequentially transmits multiple CAN frames received from the CAN frame creation unit 14 to the data receiving device.
[0103] [Data Receiving Device] Figure 8 shows another example of the configuration of a space communication device according to an embodiment of the present disclosure. Figure 8 shows the configuration of space communication device 101B or space communication device 101C, i.e., a data receiving device.
[0104] Referring to Figure 8, the data receiving device comprises a communication unit 21, a restoration unit 22, a packet processing unit 23, and a storage unit 24. Some or all of the communication unit 21, the restoration unit 22, and the packet processing unit 23 are implemented by, for example, one or more processing circuits. The storage unit 24 is a non-volatile memory included in the processing circuit. The communication unit 21 is an example of a receiving unit.
[0105] The communication unit 21 receives CAN frames from the space communication device 101A. More specifically, the communication unit 21 sequentially receives multiple CAN frames from the space communication device 101A.
[0106] The communication unit 21 outputs the CAN frame to the reconstruction unit 22 each time it receives a CAN frame from the space communication device 101A.
[0107] (Restoration Unit) The restoration unit 22 combines the multiple segmented data contained in each of the multiple CAN frames received by the communication unit 21 and performs restoration processing to restore the data contained in the space packet P1 acquired by the data transmission device.
[0108] More specifically, the restoration unit 22 restores the CAN-MA packet containing the space packet P1 by combining the multiple segmented packets contained in each of the multiple CAN frames received by the communication unit 21.
[0109] Specifically, when the restoration unit 22 receives a CAN frame from the communication unit 21, it checks the value of "Data Field Sequence" in the CAN frame. For example, if the value of "Data Field Sequence" in the CAN frame received from the communication unit 21 is "1" or "zero", the restoration unit 22 determines that the CAN frame is not the last CAN frame transmitted from the data transmission device. The restoration unit 22 then stores the CAN frame in the storage unit 24.
[0110] The restoration unit 22 determines that a CAN frame received from the communication unit 21 is the last CAN frame if the "Data Field Sequence" value in that CAN frame is "2". Then, the restoration unit 22 uses that CAN frame and multiple CAN frames stored in the storage unit 24, where the "Data Field Sequence" value is "1" or "zero", to restore the CAN-MA packet.
[0111] The restoration unit 22 then performs error detection on the header Ha and data field Da in the restored CAN-MA packet. For example, the storage unit 24 stores the same generator polynomial as the one held by the data transmission device.
[0112] The restoration unit 22 calculates the remainder by dividing the header Ha and data field Da of the restored CAN-MA packet by the generation polynomial stored in the storage unit 24. The restoration unit 22 compares the calculated remainder with the CRC code in the restored CAN-MA packet.
[0113] If the calculated remainder and the CRC code in the restored CAN-MA packet are the same, the restoration unit 22 outputs the CAN-MA packet to the packet processing unit 23.
[0114] On the other hand, if the calculated remainder differs from the CRC code in the restored CAN-MA packet, the restoration unit 22 discards the CAN-MA packet.
[0115] (Packet Processing Unit 23) The packet processing unit 23 performs predetermined processing using the CAN-MA packets restored by the restoration unit 22.
[0116] More specifically, when the packet processing unit 23 receives a CAN-MA packet from the restoration unit 22, it checks the flags F1 and F2 of the header Ha in the CAN-MA packet.
[0117] Then, the packet processing unit 23 performs a Write operation if flags F1 and F2 are "1" and "1", respectively. More specifically, the packet processing unit 23 writes the space packet P11 containing the observation data, which is stored in the data field Da of the CAN-MA packet received from the restoration unit 22, to the storage unit 24.
[0118] Specifically, the packet processing unit 23 writes the space packet P11 stored in the data field Da to an empty address stored in the header Ha. The packet processing unit 23 may also be configured to write the observed data to an arbitrary address in the storage unit 24. In other words, the header Ha does not necessarily have to include an empty address.
[0119] When the packet processing unit 23 completes the Write process, it sends write completion information to the data transmission device indicating that the Write process has been completed.
[0120] When the data transmission device shown in Figure 3 receives write completion information from the data receiving device, it updates the usage status table Tb1 in the storage unit 16. Specifically, for example, the data transmission device changes the write status in the usage status table Tb1 to "written" at the address corresponding to the write completion information received from the data receiving device.
[0121] On the other hand, in the data receiving device, if flags F1 and F2 are "zero" and "zero," respectively, the packet processing unit 23 performs predetermined processing using the space packet P12 containing the observed data stored in the data field Da of the CAN-MA packet received from the restoration unit 22. For example, the packet processing unit 23 uses the space packet P12 to generate a control signal for controlling equipment (not shown) connected to its own data receiving device.
[0122] [Operation Flow] Next, the operation flow of each device in the space communication system 501 according to the embodiment of this disclosure will be explained with reference to the drawings.
[0123] Figure 9 is a flowchart illustrating an example of the operation procedure when a data transmission device according to an embodiment of the present disclosure performs the process of transmitting a CAN frame. Figure 9 shows a case in which the data transmission device transmits a CAN frame containing segmented data obtained by dividing the observed data contained in a space packet P11.
[0124] Referring to Figure 9, first, the data transmission device waits for the processing timing T of the creation process C1, which creates the space packet P11, to arrive (NO in step ST101).
[0125] Then, when the processing timing T arrives (YES in step ST101), the data transmission device retrieves multiple observation data stored in the storage unit 16 during the period from the previous processing timing T to the current processing timing T (step ST102).
[0126] Next, the data transmission device creates a space packet P11 containing the extracted observation data (step ST103).
[0127] Next, the data transmission device creates a CAN-MA packet containing a header Ha storing write request information and an available address, a data field Da storing the created space packet P11, and a CRC code (step ST104).
[0128] Next, the data transmission device divides the created CAN-MA packet into multiple segmented packets (step ST105).
[0129] Next, the data transmission device creates multiple CAN frames, each containing multiple segmented packets (step ST106).
[0130] Next, the data transmission device sequentially transmits the multiple CAN frames it has created to the data receiving device (step ST107) and waits for the next processing timing T to arrive (NO in step ST101).
[0131] Figure 10 is a flowchart illustrating an example of the operation procedure when a data transmission device according to an embodiment of the present disclosure performs the process of transmitting a CAN frame. Figure 10 shows a case in which the data transmission device transmits a CAN frame containing segmented data obtained by dividing the observed data contained in a space packet P12.
[0132] Referring to Figure 10, first, the data transmission device waits for the reception of data request information from the data receiving device (NO in step ST201).
[0133] Then, when the data transmission device receives data request information from the data receiving device (YES in step ST201), it retrieves the observed data for the address indicated by the data request information from the storage unit 16 (step ST202).
[0134] Next, the data transmission device creates a space packet P12 containing the extracted observation data (step ST203).
[0135] Next, the data transmission device creates a CAN-MA packet having a header Ha containing read completion information, a data field Da containing the created space packet P12, and a CRC code (step ST204).
[0136] Steps ST205 and ST206 are the same as steps ST105 and ST106 shown in Figure 9, respectively.
[0137] Next, the data transmission device sequentially transmits the multiple CAN frames it has created to the data receiving device (step ST207) and waits for the reception of new data request information from the data receiving device (NO in step ST201).
[0138] Figures 11 and 12 are flowcharts illustrating an example of the operation procedure when a data receiving device according to an embodiment of the present disclosure performs a restoration process.
[0139] Referring to Figures 11 and 12, first, the data receiving device waits for the reception of a CAN frame from the data transmitting device (NO in step ST301).
[0140] The data receiving device then receives a CAN frame from the data transmitting device, and if the value of "Data Field Sequence" in the CAN frame is "1" or "zero" (YES in step ST301 and YES in step ST302), it stores the CAN frame in the storage unit 24 (step ST303) and waits for the reception of a new CAN frame from the data transmitting device (NO in step ST301).
[0141] On the other hand, if the value of "Data Field Sequence" in the received CAN frame is "2" (YES in step ST301 and NO in step ST302), the data receiving device performs a restoration process to restore the CAN-MA packet using the segmented packets contained in the received CAN frame and the segmented packets contained in other CAN frames stored in the storage unit 24 (step ST304).
[0142] Next, the data receiving device performs error detection on the restored CAN-MA packets (step ST305).
[0143] Next, if no errors are detected in the restored CAN-MA packet (NO in step ST305), the data receiving device performs predetermined processing using the CAN-MA packet (step ST306).
[0144] On the other hand, if the data receiving device detects an error in the restored CAN-MA packet (YES in step ST305), it discards the CAN-MA packet (step ST307).
[0145] Figure 13 is a diagram showing an example of the processing sequence of a data transmission device and a data reception device in a space communication system according to an embodiment of the present disclosure. Figure 13 shows a case where the segmented packets included in the CAN frame transmitted by the data transmission device to the data reception device are segmented packets obtained by dividing a CAN-MA packet in which a space packet P11 is stored in the data field Da.
[0146] Referring to Figure 13, first, the data transmission device creates a space packet P11 containing the observation data (step ST401).
[0147] Next, the data transmission device creates a CAN-MA packet containing a write request information, a header Ha storing a free address in the storage unit 24 of the data reception device, a data field Da storing the created space packet P11, and a CRC code (step ST402).
[0148] Next, the data transmission device divides the created CAN-MA packet into multiple segmented packets (step ST403).
[0149] Next, the data transmission device creates multiple CAN frames, each containing multiple segmented packets (step ST404).
[0150] Next, the data transmission device sequentially transmits the multiple CAN frames it has created to the data receiving device (step ST405).
[0151] Next, when the data receiving device receives all of the multiple CAN frames, each containing multiple segmented packets, from the data transmitting device, it uses the multiple segmented packets to reconstruct the CAN-MA packet (step ST406).
[0152] Next, the data receiving apparatus performs error detection on the restored CAN-MA packet. Here, it is assumed that the data receiving apparatus does not detect an error in the CAN-MA packet (step ST407).
[0153] Next, the data receiving apparatus performs predetermined processing using the restored CAN-MA packet. Here, the data receiving apparatus performs processing for writing the space packet P11 stored in the data field Da of the CAN-MA packet into the storage unit 24, that is, a Write process, in accordance with the write request information included in the restored CAN-MA packet (step ST408).
[0154] Note that, in the space communication system 501 according to the embodiment of the present disclosure, the data transmitting apparatus is configured to store divided packets obtained by dividing a CAN-MA packet, that is, packets obtained by dividing the space packet P1, into a CAN frame and transmit the CAN frame to the data receiving apparatus; however, the configuration is not limited thereto. The data transmitting apparatus may be configured to store divided data in a frame conforming to the CAN FD standard and transmit the frame to the data receiving apparatus.
[0155] Furthermore, in the space communication system 501 according to the embodiment of the present disclosure, the data transmitting apparatus is configured to store the space packet P1 in the data field Da of a packet that conforms to a protocol of a layer lower than the network layer in the OSI reference model and higher than the physical layer, and the packet has a header Ha and a CRC code; however, the configuration is not limited thereto. The packet in which the space packet P1 is stored does not need to include at least one of the header Ha and the CRC code.
[0156] Furthermore, in the space communication system 501 according to the embodiment of this disclosure, the data transmission device is configured to divide a CAN-MA packet containing write request information or read completion information, i.e., a CAN-MA packet containing information indicating whether the data contained in the data field Da is data corresponding to a Write process or data corresponding to a Read process, and store it in a CAN frame, but is not limited to this. The type of data transmitted to the data receiving device may be data related to purposes other than Write and Read processes.
[0157] Furthermore, while the space communication system 501 according to the embodiments of this disclosure is configured such that the data transmission device and the data reception device are each installed in an onboard subsystem 401 of a spacecraft 301, the disclosure is not limited to this configuration. The spacecraft 301 on which the data transmission device is installed and the spacecraft 301 on which the data reception device is installed may have different configurations. Also, the data transmission device and the data reception device may each be installed in a ground station that communicates with the spacecraft 301. In addition, when a vehicle communicates with the spacecraft 301, the data transmission device and the data reception device may each be installed in the vehicle. Furthermore, the data transmission device and the data reception device may each be installed in a subsystem of a spacecraft 301.
[0158] [Modification 1] Commands and replies transmitted and received between space communication devices 101 in the onboard subnetwork 401 may be assigned a priority.
[0159] Figure 14 is a diagram illustrating the priority set for commands and replies transmitted and received by Modification 1 of the space communication device according to the embodiment of this disclosure.
[0160] Referring to Figure 14, in the space communication system 501, for each command and reply, two types of priority, such as high and low, are set.
[0161] The space communication device 101 modifies the CAN-ID (Identifier) included in the CAN frame according to the command priority and the reply priority.
[0162] In the example shown in Figure 14, the CAN-ID of a CAN frame sent by a controller node, containing a "high priority command" and "various data," is "0x300" with the ID of the responder node to which the CAN frame is sent appended. The CAN-ID of a CAN frame sent by a responder node, containing a "high priority reply" and "various data," is "0x400" with the ID of the responder node appended. The CAN-ID of a CAN frame sent by a controller node, containing a "low priority command" and "various data," is "0x500" with the ID of the responder node to which the CAN frame is sent appended. The CAN-ID of a CAN frame sent by a responder node, containing a "low priority reply" and "various data," is "0x600" with the ID of the responder node appended. Here, a number starting with "0x" means that the numbers after "0x" are represented in hexadecimal.
[0163] Incidentally, in the space communication system 501, the time constraints on data may differ depending on the type of data. For example, for data transmitted and received in the onboard subnetwork 401, such as data related to status monitoring and anomaly detection, the required time from when the controller node sends a command until it receives a reply may be set shorter compared to other data such as data transmitted and received between spacecraft 301s and data transmitted and received between spacecraft 301s and ground stations. As described above, by setting priorities for each command and reply, the space communication system 501 can handle both the transmission and reception of data with strict time constraints and data with loose time constraints.
[0164] [Modification 2] The data transmission device may be configured to transmit a CAN frame having the following structure to the data receiving device.
[0165] Figure 15 shows an example of the format of the DAT field in a CAN frame transmitted by a modified example 2 of the data transmission device according to the embodiment of this disclosure.
[0166] In Figure 15, the vertical direction represents bytes and the horizontal direction represents bits. The format of the DAT field in the CAN frame shown in Figure 15 differs from the format shown in Figure 7 in that the lower 6 bits of the "zero" byte in the DAT field represent "Data Field Count," and the segmented packets are stored in bytes "1" through "7" of the DAT field. This makes it possible to increase the data size of segmented packets that can be stored in the DAT field.
[0167] [Modification 3] Alternatively, the data transmission device may be configured to transmit a CAN frame with the following structure to the data receiving device.
[0168] Figures 16, 17, and 18 show an example of the format of the DAT field in a CAN frame transmitted by Modification 3 of the data transmission device according to the embodiment of the present disclosure. In Figures 16, 17, and 18, the vertical direction represents bytes and the horizontal direction represents bits.
[0169] The DAT field format shown in Figure 16 represents the format of the DAT field in the first CAN frame transmitted by the data transmitter to the data receiver. The DAT field format shown in Figure 17 represents the format of the DAT field in an intermediate frame transmitted by the data transmitter to the data receiver. The DAT field format shown in Figure 18 represents the format of the DAT field in the final CAN frame transmitted by the data transmitter to the data receiver.
[0170] Referring to Figure 16, in the DAT field of the first CAN frame, the zeroth and first bytes represent a flag sequence S1 indicating that it contains the first segmented packet. In the example shown in Figure 16, the flag sequence S1 is "0x0001".
[0171] In the DAT field of the first CAN frame, the segmented packets are stored in bytes 2 through 7.
[0172] Referring to Figure 17, in the DAT field of the intermediate frame, the segmented packets are stored in bytes 0 through 7.
[0173] Referring to Figure 18, in the DAT field of the last CAN frame, the segmented packets are stored in bytes 0 through 5.
[0174] In the DAT field of the last CAN frame, the 6th and 7th bytes represent a flag sequence S2 indicating that it contains the last split packet. In the example shown in Figure 18, the flag sequence S2 is "0x0002".
[0175] In this configuration, where each of the multiple CAN frames transmitted from the data transmitting device to the data receiving device has a flag sequence S1 and a flag sequence S2, it becomes unnecessary to include information indicating which CAN frame it is in the intermediate frame. Furthermore, it is possible to include a segmented packet with the same data length as the maximum data length of the DAT field. Therefore, when the data length of the CAN-MA packet is large, the number of CAN frames transmitted and received between the data transmitting device and the data receiving device can be reduced.
[0176] [Modification 4] Alternatively, the data transmission device may be configured to create a CAN frame containing other data in addition to the data included in the space packet P1 and transmit it to the data receiving device.
[0177] Referring again to Figures 2 and 3, for example, the data transmission device may be configured to transmit to the data receiving device a CAN frame containing data different from the data contained in the space packet P1. This other data is, for example, data obtained from another device other than the data receiving device when that device is connected to the data transmission device via the CAN bus 51.
[0178] Furthermore, for example, a data transmission device may be configured to acquire a packet P2 in addition to a space packet P1, which conforms to another standard for space communications other than the Space Packet Protocol. Such other standards include CFDP (CCSDS File Delivery Protocol), etc.
[0179] In this case, for example, the data transmission device creates a CAN frame that includes the divided data obtained by dividing the data contained in space packet P1, as well as the divided data obtained by dividing the data contained in packet P2, and transmits it to the data receiving device.
[0180] The embodiments described above should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and all modifications within the meaning and scope of the claims are intended to be included.
[0181] Each process (each function) in the above-described embodiment is implemented by a processing circuit including one or more processors. The processing circuit may consist of an integrated circuit, etc., which combines one or more memories, various analog circuits, and various digital circuits in addition to the one or more processors. The one or more memories store programs (instructions) that cause the one or more processors to execute each of the above processes. The one or more processors may execute each of the above processes according to the programs read from the one or more memories, or they may execute each of the above processes according to logic circuits that have been designed in advance to execute each of the above processes. The above-mentioned processor may be various processors suitable for computer control, such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), and ASIC (Application Specific Integrated Circuit). Furthermore, multiple physically separated processors may cooperate with each other to perform the above-mentioned processes. For example, processors installed in multiple physically separated computers may cooperate with each other via a network such as a LAN (Local Area Network), WAN (Wide Area Network), and the Internet to perform the above-mentioned processes. The above program may be installed on the above memory via the above network from an external server device, or it may be distributed on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory), or semiconductor memory, and then installed on the above memory from the above recording medium.
[0182] The above description includes the following features: [Addendum 1] A space communication method in a space communication device, comprising the steps of: acquiring a packet conforming to a first standard used in space communication; creating a frame conforming to a second standard which is a CAN or CAN FD standard, wherein the data contained in the acquired packet is divided into segmented data; and transmitting the created frame to another device.
[0183] [Note 2] A space communication method for a space communication device used in a space communication system, comprising the steps of: receiving a frame from another space communication device, which is a frame conforming to the CAN or CAN FD standard, and which stores divided data obtained by dividing data contained in a packet used in space communication; and restoring the data by combining a plurality of the divided data contained in each of the received plurality of frames.
[0184] [Note 3] A space communication device comprising a processing circuit, the processing circuit acquiring packets in accordance with a first standard used in space communications, creating a frame in accordance with a second standard which is a CAN or CAN FD standard, and transmitting the created frame to another device.
[0185] [Note 4] A space communication device used in a space communication system, comprising a processing circuit, the processing circuit receiving a frame from another space communication device, the frame being a frame conforming to the CAN or CAN FD standard, the frame containing divided data obtained by dividing data included in a packet used in space communication, and the space communication device restoring the data by combining the multiple divided data included in each of the received frames.
[0186] 11 Observation Unit 12 Space Packet Acquisition Unit 13 CAN-MA Packet Creation Unit 14 CAN Frame Creation Unit 15, 21 Communication Unit 16, 24 Memory Unit 22 Restoration Unit 23 Packet Processing Unit 51 CAN Bus 101, 101A, 101B Space Communication Device 301, 301A, 301B Spacecraft 501 Space Communication System
Claims
1. A space communication system comprising a first space communication device and a second space communication device, wherein the first space communication device acquires a first packet in accordance with a first standard used in space communication, the first space communication device stores the divided data obtained from the acquired first packet into frames in accordance with a second standard which is a standard for CAN or CAN FD and transmits them to the second space communication device, and the second space communication device combines the multiple divided data contained in each of the multiple frames received from the first space communication device to restore the data.
2. The space communication system according to claim 1, wherein the first space communication device creates a second packet that includes a header indicating the type of data, the data, and a CRC code, and conforms to a third standard different from the first and second standards, and the first space communication device divides the created second packet and stores it in the frame.
3. The space communication system according to claim 1 or 2, wherein the first space communication device creates a second packet containing the data and conforming to a third standard different from the first and second standards, the second packet further includes information indicating a request to write the data to the memory of the second space communication device, or information indicating that the data requested by the second space communication device has been read from the memory of the first space communication device, and the first space communication device divides the created second packet and stores it in the frame.
4. The space communication system according to any one of claims 1 to 3, wherein the first space communication device transmits to the second space communication device a frame containing data which is divided data, in addition to the divided data, other data different from the data contained in the first packet.
5. The space communication system according to claim 2 or 3, wherein the first space communication device further acquires a third packet conforming to a fourth standard used in space communication, which is different from the first standard, and the first space communication device creates a second packet which further includes the data contained in the third packet in addition to the data contained in the first packet.
6. A space communication device comprising: an acquisition unit that acquires packets in accordance with a first standard used in space communications; a creation unit that creates a frame in accordance with a second standard, which is a CAN or CAN FD standard, and which includes divided data obtained by dividing the data contained in the packets acquired by the acquisition unit; and a transmission unit that transmits the frame created by the creation unit to another device.
7. A space communication device used in a space communication system, comprising: a receiving unit that receives a frame from another space communication device, which is a frame conforming to the CAN or CAN FD standard, and which stores divided data obtained by dividing data contained in a packet used in space communication; and a restoring unit that combines a plurality of the divided data contained in each of the plurality of frames received by the receiving unit to restore the data.
8. A space communication method in a space communication system comprising a first space communication device and a second space communication device, the method comprising: the first space communication device acquiring a first packet in accordance with a first standard used in space communication; the first space communication device storing divided data, obtained by dividing the data contained in the acquired first packet, into a frame in accordance with a second standard which is a standard for CAN or CAN FD, and transmitting it to the second space communication device; and the second space communication device combining a plurality of the divided data contained in a plurality of frames received from the first space communication device to restore the data.
9. A space communication program for use in space communication equipment, which causes a computer to function as an acquisition unit that acquires packets in accordance with a first standard used in space communication, and a transmission unit that stores the divided data obtained from the packets acquired by the acquisition unit into frames in accordance with a second standard which is a standard for CAN or CAN FD, and transmits them to another device.
10. A space communication program used in a space communication device used in a space communication system, the program causing a computer to function as a receiving unit that receives frames from another space communication device, frames conforming to the CAN or CAN FD standard, wherein frames contain divided data obtained by dividing data included in packets used in space communication; and a restoring unit that combines a plurality of the divided data contained in each of the plurality of frames received by the receiving unit to restore the data.