A method and system for satellite-ground data transmission for on-orbit satellite software

Abstract

The present invention discloses a space-ground data transmission method and system for satellite on-orbit software. The method includes: the ground data transmission end encapsulates the data transmission task file according to the multi-layer protocol format and places it in the buffer; calculates the transmission frequency of the data frames in the sending buffer, and sends the data frames in the buffer frame by frame using the transmission frequency; the target on-board device decrypts the received data frames and parses the data transmission task file; determines whether there is a transmission file in the data transmission task. If there is, verifies the decrypted data frames, and sends a retransmission request to the ground data transmission end when the verification fails, and counts the data frames when the verification is successful; when the count reaches the total value of the sent data frames, replies to the ground data transmission end that the data transmission task file transmission is completed, and splices and stores the decrypted data frames; if not, writes the data transmission task into the data transmission task file and replies to the ground data transmission end that the data transmission task is completed.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and particularly to a space-ground data transmission method and system for satellite on-orbit software. Background Art

[0002] With the increasing complexity of satellite functions, higher requirements are put forward for the control accuracy, stability, and intelligence level of satellite platforms. The performance of traditional on-board computers is insufficient to meet the computing power requirements. Due to the increasing demand for on-orbit deployment of intelligent applications, heterogeneous computing needs to be adopted to achieve computing acceleration and provide sufficient and flexible computing resources.

[0003] An existing data uploading method for satellite on-orbit software reconstruction, CN112003643B, can, without adding new ground station hardware and satellite hardware, based on the existing space-ground TT&C system and satellite platform, through the design of the space-ground data transmission protocol, support the uploading of both remote control commands and software reconstruction data, achieve the space-ground uploading of software reconstruction data at the level of hundreds of megabits within several minutes, and store the data in the on-board solid-state memory. Although this method can realize the transmission of space-ground data, it has the following deficiencies:

[0004] This method has great limitations, that is, it cannot adapt to existing data transmission protocols. This method transmits remote control commands and data transmission data by mixing them in a data frame, and adjusts the uploading rate (transmission frequency) of software reconstruction data through the mixing ratio of the two. Since the uploading rate only considers the mixing ratio, packet loss is likely to occur during data transmission when the data transmission channel is occupied. Summary of the Invention

[0005] Aiming at the above deficiencies in the prior art, the space-ground data transmission method and system for satellite on-orbit software provided by the present invention solve the problem that packet loss easily occurs in the prior art when data is transmitted using the transmission frequency calculated based on the mixing ratio.

[0006] To achieve the above invention purpose, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, a space-ground data transmission method for satellite on-orbit software is provided, which includes the steps of:

[0008] S1. The ground data transmission end reads the data transmission task file in JSON format in the data transmission task, encapsulates the data transmission task file according to the multi-layer protocol format, and then puts the encapsulated data frame into the buffer;

[0009] S2. Calculate the transmission frequency of the data frames in the transmission buffer according to the average response time interval when the data frames are sent, and send the data frames in the buffer to the target on-board device frame by frame using the transmission frequency;

[0010] S3. The target on-board device decrypts the received data frames according to the multi-layer protocol format and parses the data transmission task file;

[0011] S4. According to the parameters of the parsed data transmission task, determine whether there is a transmission file for the data transmission task. If there is, go to step S5; otherwise, go to step S7;

[0012] S5. Verify the decrypted data frames, and send a retransmission request to the ground data transmission end when the verification fails, and count the data frames when the verification is successful;

[0013] S6. When the count reaches the total value of the sent data frames, reply to the ground data transmission end that the data transmission task file transmission is completed, splice and store the decrypted data frames, and then go to step S7;

[0014] S7. The target on-board device writes the data transmission task into the data transmission task file and replies to the ground data transmission end that the data transmission task is completed.

[0015] Further, the expression for calculating the transmission frequency of the data frames in the transmission buffer is:

[0016]

[0017]

[0018] where f n is the transmission frequency after the n th adjustment; T n and T n-1 are the transmission time intervals after the n th and n -1th adjustments respectively; A n is the coefficient for adjusting the transmission frequency at the n th time; t α is the minimum adjusted transmission time interval; and are the average values of the time from the start of the n th and n -1th transmissions before adjusting the transmission frequency to receiving the reply, statistically for the first M times; is the n th time before adjusting the transmission frequency, and thei The time interval from the start of transmission to receiving a reply during the successful communication between the satellite and the ground for the first time.

[0019] Furthermore, the time average has the following expression:

[0020]

[0021] where M is the number of times of the satellite-ground communication time statistics, i is a variable.

[0022] Furthermore, when n = 1, calculate T n-1 has the following expression:

[0023]

[0024] where T 0 is the first transmission time interval; f recv is the buffer reading frequency of the ground data transmission end; S recv is the buffer size of the ground data transmission end; W band is the bandwidth size; N thread is the number of threads used; S send is the maximum size of the data frame to be sent.

[0025] Furthermore, after encapsulating the data transmission task file, it also includes:

[0026] A1. Determine whether a load file needs to be transmitted during the transmission of the current data transmission task file. If so, go to step A2; otherwise, go to step S2;

[0027] A2. Unpack the load file according to the load size of the first-layer protocol in the multi-layer protocol format, and encapsulate the unpacked data using a data frame encapsulator.

[0028] Furthermore, the JSON format includes three layers of parameters. The first-layer parameters are the overall parameters of the multi-layer protocol; the second-layer parameters are the parameters of a single protocol; the third-layer parameters are the parameters of a single protocol field.

[0029] Furthermore, the overall parameters include the number of protocols and the protocol array. The number of protocols is the number of layers of the protocol that needs to be encapsulated for transmitting data, and the protocol array is the specific parameters of each layer of the protocol; the parameters of a single protocol include the protocol name, the total protocol length, the number of fields, and the field parameter list; the parameters of a single protocol field include the field name, the field length, and the field reserved parameters.

[0030] In a second aspect, a system for a space-ground data transmission method applied to on-orbit satellite software is provided, which includes a ground data transmission terminal and a target on-board device. The ground data transmission terminal includes a ground data transmission device, a data unpacker for unpacking a data transmission task file and a load file, a data frame encapsulator for encapsulating the split data according to a multi-layer protocol format, and a data transceiver controller connected to the data frame encapsulator. The ground data transmission device is configured to store the encapsulated data sent by the data transceiver controller in its buffer area, calculate the transmission frequency, and send a data frame to the target on-board device according to the transmission frequency.

[0031] The target on-board device includes an on-board main device for receiving the data frame sent by the ground data transmission device, an on-board data transceiver controller for sending the data frame received by the on-board main device to a data frame de-encapsulator, a data frame de-encapsulator for de-encapsulating the received data frame according to a multi-layer protocol format, and a data packet gluer for splicing the de-encapsulated data.

[0032] The data transceiver controller is configured to parse the data transmission task file, and based on the parameters of the parsed data transmission task, determine whether there is a transmission file for the data transmission task. If there is, it checks the de-encapsulated data frame, and when the check fails, sends a retransmission request to the ground data transmission terminal. When the check is successful, it counts the data frame. When the count reaches the total value of the sent data frames, it replies to the ground data transmission terminal that the data transmission task file transmission is completed, and splices and stores the de-encapsulated data frames. If not, it writes the data transmission task into the data transmission task file and replies to the ground data transmission terminal that the data transmission task is completed.

[0033] The beneficial effects of the present invention are as follows: When performing space-ground data transmission, through the average response time interval of the target on-board device, the congestion situation of the data transmission channel can be determined. On this basis, the transmission frequency of the sent data frame is dynamically adjusted to avoid data frame loss, so as to make full use of the space-ground channel transmission resources.

[0034] The data transmission task file of this solution is based on the JSON format, which can adapt to the data frame encapsulation format used by existing satellites, and adjust the supported multi-layer protocol format according to the actual model satellite, so as to ensure that this solution can adapt to multiple protocols in the prior art.

[0035] When performing data transmission in this solution, the transmission frequency is determined based on the average response time interval of the target on-board device, which takes into account the congestion situation of the channel transmission. During the data transmission process, it does not continuously occupy the transmission channel, so as not to affect higher-priority data transmission tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flowchart of a space - ground data transmission method for satellite on - orbit software.

[0037] Figure 2 It is a schematic block diagram of the principle of a space - ground data transmission system for satellite on - orbit software.

[0038] Figure 3 It is a schematic diagram for parsing the JSON protocol format. Specific embodiments

[0039] The following describes the specific embodiments of the present invention to facilitate those skilled in the art of this technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of this technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0040] Referring to Figure 1 , Figure 1 shows a flowchart of a space - ground data transmission method for satellite on - orbit software; as Figure 1 shown, this method S includes steps S1 to S7.

[0041] In step S1, the ground data transmission end reads the data transmission task file in JSON format in the data transmission task, encapsulates the data transmission task file according to the multi - layer protocol format, and then puts the encapsulated data frame into the buffer;

[0042] In implementation, it is preferably that the JSON format in this solution includes three - layer parameters. The first - layer parameters are the overall parameters of the multi - layer protocol, which include the number of protocols and the protocol array. The number of protocols is the number of layers of the protocol that needs to encapsulate the transmitted data, and the protocol array is the specific parameters of each layer of the protocol; the second - layer parameters are the parameters of a single protocol, which include the protocol name, the total length of the protocol, the number of fields, and the field parameter list; the third - layer parameters are the parameters of a single protocol field, which include the field name, the field length, and the field reserved parameter.

[0043] Among them, the protocol name is the name of this layer of protocol, which only has an identification meaning. The total length of the protocol is the maximum overall length after encapsulation of this protocol. The number of fields is the total number of segments of this protocol. The field parameter list is the specific parameter of each field; the field name is the name of this field, which only has an identification meaning. The field length is in bits as the minimum unit (1 byte equals 8 bits), indicating the effective length of this field. The field reserved parameter is a parameter unique to each field. For example, the reserved parameter of the checksum field is the check type, which is used to identify the calculation method of this field. The data in JSON format has great flexibility. If the existing parameters of a certain layer of protocol parameters cannot be fully identified, it can also be flexibly added for adaptation.

[0044] The multi - layer protocol format is the protocol parameters encapsulated in JSON format. Specifically, the JSON representation description of the multi - layer protocol format can be referred to Table 1.

[0045] Table 1 JSON representation description of multi - layer protocol format

[0046]

[0047] In step S2, according to the average reply time interval when the data frame is sent, calculate the sending frequency of the data frames in the sending buffer, and send the data frames in the buffer to the target on - board device frame by frame using the sending frequency.

[0048] During implementation, the preferred expression for calculating the sending frequency of the data frames in the sending buffer in this solution is:

[0049]

[0050]

[0051] Among them, f n is the sending frequency after the n th adjustment; T n and T n-1 are the sending time intervals after the n , n -1th adjustments respectively; A n is the coefficient for adjusting the sending frequency at the n th time; t α is the minimum adjustment of the sending time interval; and are the time means from the start of the n , n -1th times of sending frequency adjustment to receiving the reply, statistically calculated for the previous M times; is the time interval from the start of sending to receiving the reply during the n th successful satellite - ground communication of the ground data transmission end before the i th adjustment of the sending frequency.

[0052] Among them, the expression of the time mean is:

[0053]

[0054] Among them, M is the number of times of satellite - ground communication time statistically calculated, i is a variable.

[0055] When n = 1, calculate the T n-1 expression as:

[0056]

[0057] wherein, T 0 is the first transmission time interval; f recv is the buffer reading frequency of the ground data transmission end; S recv is the buffer size of the ground data transmission end; W band is the bandwidth size; N thread is the number of threads used; S send is the maximum size of the data frame to be sent.

[0058] In step S3, the target on-board device unpacks the received data frame according to the multi-layer protocol format and parses the data transmission task file;

[0059] In step S4, according to the parameters of the parsed data transmission task, determine whether there is a transmission file for the data transmission task. If so, go to step S5; otherwise, go to step S7. The parameters of the data transmission task may include the size of the transmission file, file name, file path, file checksum, file check type, whether the file needs to be differenced, whether the file needs to be compressed, etc.

[0060] In step S5, check the unpacked data frame, and send a retransmission request to the ground data transmission end when the check fails, and count the data frame when the check is successful;

[0061] In step S6, when the count reaches the total value of the data frames to be sent, reply to the ground data transmission end that the data transmission task file transmission is completed, splice and store the unpacked data frames, and then go to step S7;

[0062] In step S7, the target on-board device writes the data transmission task into the data transmission task file and replies to the ground data transmission end that the data transmission task is completed.

[0063] In an embodiment of the present invention, after encapsulating the data transmission task file, it further includes:

[0064] A1. Determine whether a load file needs to be transmitted during the transmission of the current data transmission task file. If so, go to step A2; otherwise, go to step S2;

[0065] A2. Unpack the payload file according to the payload size of the first-layer protocol in the multi-layer protocol format, and encapsulate the unpacked data using a data frame encapsulator, then proceed to step S2.

[0066] The data transfer task file is used to describe this data transfer task, including simple transfer data and some parameters related to the transfer task. The payload file is the file to be mainly transferred in this data transfer task, which can be understood as the main object of this transfer task. When making a judgment, it can be known according to the information included in the parameters of the data transfer task.

[0067] The detailed processing flow of step A2 is as follows: The ground data transfer end uses a data unpacker to unpack the payload file according to the payload size of the first-layer protocol in the multi-layer protocol format, and uses a data frame encapsulator to encapsulate the unpacking result (including the filling of each field of the frame header and the calculation of the check code). This solution adopts Figure 3 the JSON protocol format parsing shown, which can flexibly support existing protocol formats, and according to actual needs, also supports multi-level protocol encapsulation. For different satellites, just configure different protocol format parsing documents.

[0068] Such as Figure 2 shown, this solution also provides a system for the space-ground data transfer method applied to the on-orbit satellite software, which includes a ground data transfer end and a target on-board device. The ground data transfer end includes a ground data transfer device, a data unpacker for unpacking the data transfer task file and the payload file, a data frame encapsulator for encapsulating the split data according to the multi-layer protocol format, and a data transceiver controller connected to the data frame encapsulator; The ground data transfer device is used to store the encapsulated data sent by the data transceiver controller in its buffer area and calculate the sending frequency, and send data frames to the target on-board device according to the sending frequency;

[0069] The target on-board device includes an on-board main device for receiving data frames sent by the ground data transfer device, an on-board data transceiver controller for sending the data frames received by the on-board main device to a data frame de-encapsulator, a data frame de-encapsulator for de-encapsulating the received data frames according to the multi-layer protocol format, and a data packet assembler for splicing the de-encapsulated data;

[0070] The data transceiver controller is used to parse the data transmission task file, and based on the parameters of the parsed data transmission task, determine whether there is a transmission file for the data transmission task. If there is, it checks the decrypted data frame, and when the check fails, sends a retransmission request to the ground data transmission end. When the check is successful, it counts the data frames; when the count reaches the total value of the sent data frames, it replies to the ground data transmission end that the data transmission task file transmission is completed, and splices and stores the decrypted data frames; if not, it writes the data transmission task into the data transmission task file and replies to the ground data transmission end that the data transmission task is completed.

[0071] The operating system of the target on-board device in this solution only requires a file system, and it is not necessary to be Linux system, Linux The system comes with a file system, which is also the future trend of the operating system for on-board devices.

[0072] In summary, since this solution can dynamically adjust the transmission frequency and make full use of the transmission bandwidth, it can, to a certain extent, alleviate the problems of low space-ground communication bandwidth and high communication costs.

Claims

1. A satellite-to-ground data transmission method for satellite on-orbit software, characterized in that: Includes steps: S1. The ground data transmission terminal reads the data transmission task file in the JSON format in the data transmission task, encapsulates the data transmission task file according to the multi-layer protocol format, and then puts the encapsulated data frame into the buffer area; S2. Calculate the sending frequency of the data frames in the sending buffer area according to the average reply time interval when the data frames are sent, and send the data frames in the buffer area to the target satellite-borne equipment frame by frame using the sending frequency; The expression for calculating the sending frequency of the data frame in the sending buffer is: in, f n For the n The sending frequency after adjustment; T n and T n-1 Respectively n , n -1 adjusted sending interval; A n For the n The coefficient for adjusting the sending frequency; t α The minimum adjustment sending time interval; and Respectively n , n -1 adjustment of the previous statistics before the sending frequency M The average time from the start of sending to receiving a reply; S3, the target satellite-borne equipment decapsulates the received data frame according to the multi-layer protocol format and parses the data transmission task file; S4, judging whether there is a transfer file for the data transmission task according to the parameters of the parsed data transmission task, if so, proceeding to step S5, otherwise proceeding to step S7; S5, verifying the unsealed data frame, and sending a retransmission request to the ground data transmission end when the verification fails, and counting the data frames when the verification succeeds; S6. When the count reaches the total value of the sent data frames, the ground data transmission end is replied that the data transmission task file transmission is completed, and the unsealed data frames are spliced ​​and stored, and then the process goes to step S7; S7. The target satellite-borne device writes the data transmission task into the data transmission task file and replies to the ground data transmission end that the data transmission task is completed.

2. The satellite-to-ground data transmission method for satellite on-orbit software according to claim 1, characterized in that: Calculate the mean time The expression is: in, M The number of satellite-to-ground communication times is counted. i is a variable; For the n Before adjusting the transmission frequency for the first time, the ground data transmission end i The time interval from sending to receiving a reply during a successful satellite-to-ground communication.

3. The satellite-to-ground data transmission method for satellite on-orbit software according to claim 1, characterized in that: when n =1, calculate T n-1 The expression is: in, T 0 is the first sending time interval; f recv Read the frequency from the buffer area of ​​the ground data transmission end; S recv is the buffer size of the ground data transmission end; W band is the bandwidth size; N thread The number of threads used; S send The maximum size of the data frame to be sent.

4. The satellite-to-ground data transmission method for satellite on-orbit software according to any one of claims 1 to 3, characterized in that: After the data transmission task file is encapsulated, it also includes: A1, determine whether the current data transmission task file needs to transmit the load file, if so, go to step A2, otherwise go to step S2; A2. Unpack the payload file according to the payload size of the layer 1 protocol in the multi-layer protocol format, and use a data frame encapsulator to encapsulate the unpacked data.

5. The satellite-to-ground data transmission method for satellite on-orbit software according to any one of claims 1 to 3, characterized in that: The JSON format includes three layers of parameters, the first layer of parameters are the overall parameters of the multi-layer protocol; The second layer parameters are the parameters of a single protocol; the third layer parameters are the parameters of a single protocol field.

6. The satellite-to-ground data transmission method for satellite on-orbit software according to claim 5, characterized in that: The overall parameters include the number of protocols and the protocol array. The number of protocols is the number of layers of protocols that need to be encapsulated for data transmission, and the protocol array is the specific parameters of each layer of protocol. The parameters of a single protocol include the protocol name, total length of the protocol, number of fields, and field parameter list. The parameters of a single protocol field include the field name, field length, and field reservation parameters.

7. A system for satellite-to-ground data transmission method for satellite on-orbit software according to any one of claims 1 to 6, characterized in that: It comprises a ground data transmission end and a target satellite-borne device, wherein the ground data transmission end comprises a ground data transmission device, a data depacketizer for depacketizing a data transmission task file and a load file, a data frame encapsulator for encapsulating the depacketized data according to a multi-layer protocol format, and a data transceiver controller connected to the data frame encapsulator; the ground data transmission device is used to store the encapsulated data sent by the data transceiver controller into its buffer area and calculate the sending frequency, and send the data frame to the target satellite-borne device according to the sending frequency; The target satellite-borne equipment includes a satellite service master device for receiving data frames sent from ground data transmission equipment, a satellite service data transceiver controller for sending data frames received by the satellite service master device to a data frame decapsulator, a data frame decapsulator for decapsulating received data frames according to a multi-layer protocol format, and a data gluer for splicing decapsulated data; The data transceiver controller is used to parse the data transmission task file, and determine whether there is a transmission file for the data transmission task according to the parameters of the parsed data transmission task, and if so, verify the unsealed data frame, and send a retransmission request to the ground data transmission end when the verification fails, and count the data frames when the verification succeeds; When the count reaches the total value of the data frames sent, the ground data transmission end is replied that the data transmission task file is completed, and the unsealed data frames are spliced ​​and stored; if it does not exist, the data transmission task is written into the data transmission task file, and the ground data transmission end is replied that the data transmission task is completed.

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