Satellite-ground data transmission method and system for satellite in-orbit software

Abstract

The invention discloses a satellite-ground data transmission method and system for satellite in-orbit software, and the method comprises the steps: packaging a data transmission task file through a ground data transmission end according to a multilayer protocol format, and putting the data transmission task file into a cache region; the sending frequency for sending the data frames in the cache region is calculated, and the data frames in the cache region are sent frame by frame by adopting the sending frequency; the target satellite-borne device unpacks the received data frame and analyzes the data transmission task file; whether a transmission file exists in the data transmission task or not is judged, if yes, the unpacked data frames are verified, a retransmission request is sent to a ground data transmission end when verification fails, and the data frames are counted when verification succeeds; when the count reaches the total value of the sent data frames, replying a ground data transmission end that the transmission of the data transmission task file is completed, and splicing and storing the unpacked data frames; and if not, writing the data transmission task into the data transmission task file, and replying 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 in particular to a satellite-to-ground data transmission method and system for satellite on-orbit software. Background Art

[0002] As satellite functions become increasingly complex, higher requirements are placed on the control accuracy, stability and intelligence level of satellite platforms. The performance of traditional onboard computers is insufficient to meet the computing power requirements. Due to the increasing demand for on-orbit deployment of intelligent applications, heterogeneous computing is needed to achieve computing acceleration and provide sufficient and flexible computing resources.

[0003] Prior art A method for uploading data for satellite on-orbit software reconstruction CN112003643B, without adding new ground station hardware and satellite hardware, based on the existing satellite-to-ground measurement and control system and satellite platform, through the design of satellite-to-ground data transmission protocol, supports uploading of remote control commands and software reconstruction data at the same time, realizes satellite-to-ground uploading of hundreds of megabits of software reconstruction data within several minutes, and stores the data in the satellite service solid-state memory. Although this method can realize the transmission of satellite-to-ground data, it has the following shortcomings: This method has a great limitation, that is, it cannot adapt to the existing data transmission protocol. This method mixes the remote control command and the data transmission data in one data frame for transmission, and adjusts the upload rate (sending frequency) of the software reconstruction data by the mixing ratio of the two. Since the upload rate only considers the mixing ratio, if the data transmission channel is occupied during the data transmission process, packet loss is likely to occur. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the satellite-to-ground data transmission method and system for satellite on-orbit software provided by the present invention solves the problem that packet loss is prone to occur when the prior art uses a sending frequency calculated based on a mixing ratio for data transmission.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is: In a first aspect, a satellite-to-ground data transmission method for satellite on-orbit software is provided, comprising the steps of: 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; 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.

[0006] Furthermore, the expression for calculating the sending frequency of the data frame in the sending buffer area is:

[0007]

[0008] 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 between sending and receiving a reply; 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.

[0009] Furthermore, the time mean The expression is:

[0010] in, MThe number of satellite-to-ground communication times is counted. i is a variable.

[0011] Furthermore, when n=1, calculate T n-1 The expression is:

[0012] 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.

[0013] Furthermore, 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.

[0014] Furthermore, the JSON format includes three layers of parameters, the first layer parameters are the overall parameters of the multi-layer protocols; the second layer parameters are the parameters of a single protocol; and the third layer parameters are the parameters of a single protocol field.

[0015] Furthermore, 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 the protocol; the parameters of a single protocol include the protocol name, the total length of the protocol, the number of fields and the field parameter list; the parameters of a single protocol field include the field name, field length and field reservation parameters.

[0016] In a second aspect, a system for a satellite-to-ground data transmission method for satellite on-orbit software is provided, which includes a ground data transmission end and a target satellite-borne device, wherein the ground data transmission end includes a ground data transmission device, a data depacketizer for unpacking a data transmission task file and a payload 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 data frames 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 the data frames received by the satellite service master device to a data frame decapsulator, a data frame decapsulator for decapsulating the received data frames according to a multi-layer protocol format, and a data gluer for splicing the 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 based on the parameters of the parsed data transmission task. If so, the unsealed data frame is verified, and a retransmission request is sent to the ground data transmission end when the verification fails, and the data frames are counted 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 transmission 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.

[0017] The beneficial effects of the present invention are as follows: when performing satellite-to-ground data transmission, the present scheme can determine the congestion of the data transmission channel through the average response time interval of the target satellite-borne equipment, and on this basis dynamically adjust the transmission frequency of sending data frames to avoid data frame loss, thereby achieving full utilization of satellite-to-ground channel transmission resources.

[0018] 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 of the satellite, thereby ensuring that this solution can adapt to multiple protocols in the existing technology.

[0019] When this scheme performs data transmission, the transmission frequency is determined based on the average response time interval of the target satellite-borne equipment. It takes into account the congestion of channel transmission and will not continuously occupy the transmission channel during the data transmission process, thereby not affecting data transmission tasks with higher priority. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flow chart of a satellite-to-ground data transmission method for satellite on-orbit software.

[0021] Figure 2 This is a principle block diagram of the satellite-to-ground data transmission system for satellite on-orbit software.

[0022] Figure 3 This is a schematic diagram of JSON protocol format parsing. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0024] refer to Figure 1 , Figure 1 A flow chart of a satellite-to-ground data transmission method for satellite on-orbit software is shown; Figure 1 As shown, the method S includes steps S1 to S7.

[0025] In step S1, the ground data transmission terminal reads the data transmission task file in the JSON format in the data transmission task, and encapsulates the data transmission task file according to the multi-layer protocol format, and then puts the encapsulated data frame into the buffer area; During implementation, the preferred JSON format of this scheme includes three layers of parameters. The first layer of 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 protocols that need to be encapsulated to transmit data, and the protocol array is the specific parameters of each layer of protocol; the second layer of 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 of parameters are the parameters of a single protocol field, which include the field name, field length and field reservation parameters.

[0026] Among them, the protocol name is the name of the protocol at this layer, which only has the meaning of identification, the total length of the protocol is the overall maximum length of the protocol after encapsulation, the number of fields is the total number of each segment of the protocol, and the field parameter list is the specific parameters of each field; the field name is the name of the field, which only has the meaning of identification, the field length is in bits as the smallest unit (1 byte equals 8 bits), indicating the effective length of the field, and the field reserved parameters are parameters unique to each field, such as the reserved parameters of the check code field are the check type, which is used to identify the calculation method of the field. Data in JSON format has great flexibility. If the existing parameters of a certain layer of protocol parameters cannot be fully identified, you can also flexibly add adaptations.

[0027] The multi-layer protocol format is a protocol parameter encapsulated in JSON format. For the specific meaning, that is, the multi-layer protocol format JSON representation, please refer to Table 1.

[0028] Table 1 Multi-layer protocol format JSON representation

[0029] In step S2, the sending frequency of the data frames in the buffer area is calculated according to the average reply time interval when the data frames are sent, and the data frames in the buffer area are sent to the target satellite-borne device frame by frame using the sending frequency; During implementation, the scheme preferably calculates the expression for the sending frequency of the data frame in the sending buffer area as follows:

[0030]

[0031] 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 between sending and receiving a reply; 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.

[0032] The time mean The expression is:

[0033] in, M The number of satellite-to-ground communication times is counted. i is a variable.

[0034] when n =1, calculate T n-1 The expression is:

[0035] 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.

[0036] In step S3, the target satellite-borne device decapsulates the received data frame according to the multi-layer protocol format and parses the data transmission task file; In step S4, based on the parsed parameters of the data transmission task, determine whether there is a transfer file for the data transmission task. If so, proceed to step S5, otherwise proceed to step S7. The parameters of the data transmission task may include the size of the transfer file, the file name, the file path, the file check code, the file check type, whether the file needs to be differentiated, whether the file needs to be compressed, etc.

[0037] In step S5, the unsealed data frame is verified, and a retransmission request is sent to the ground data transmission end when the verification fails, and the data frame is counted when the verification succeeds; In step S6, 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 transmission is completed, and the unsealed data frames are spliced ​​and stored, and then the process goes to step S7; In step 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.

[0038] In one embodiment of the present invention, after packaging the data transmission task file, the method further 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, and then enter step S2.

[0039] The data transmission task file is used to describe this data transmission task, including simple transmission data and some transmission task related parameters. The payload file is the file that needs to be mainly transmitted in this data transmission task, which can be understood as the main object of this transmission task. When judging, it can be known according to the information included in the parameters of the data transmission task.

[0040] The detailed processing flow of step A2 is as follows: the ground data transmission end uses the data depacketizer to depacketize the payload file according to the payload size of the layer 1 protocol in the multi-layer protocol format, and uses the data frame encapsulator to encapsulate the depacketization result (including the filling of each field in the frame header and the calculation of the checksum). Figure 3 The JSON protocol format parsing shown can flexibly support the existing protocol format, and according to actual needs, it also supports multi-level protocol encapsulation. For different satellites, different protocol format parsing documents can be configured.

[0041] like Figure 2 As shown, the present solution also provides a system for a satellite-to-ground data transmission method for satellite on-orbit software, which includes a ground data transmission end and a target satellite-borne device, wherein the ground data transmission end includes 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 data frames 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 the data frames received by the satellite service master device to a data frame decapsulator, a data frame decapsulator for decapsulating the received data frames according to a multi-layer protocol format, and a data gluer for splicing the 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 based on the parameters of the parsed data transmission task. If so, the unsealed data frame is verified, and a retransmission request is sent to the ground data transmission end when the verification fails, and the data frames are counted 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 transmission 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.

[0042] The operating system of the target satellite device in this solution only needs to have a file system, not necessarily Linux system, Linux The system comes with its own file system, which is also the popular operating system trend for satellite-borne devices in the future.

[0043] In summary, this scheme can dynamically adjust the transmission frequency and make full use of the transmission bandwidth, which can alleviate the problem of low bandwidth and high communication cost between satellite and ground to a certain extent.

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; 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: 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 between sending and receiving a reply; 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 2, 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.

4. The satellite-to-ground data transmission method for satellite on-orbit software according to claim 2, 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.

5. The satellite-to-ground data transmission method for satellite on-orbit software according to any one of claims 1 to 4, 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.

6. The satellite-to-ground data transmission method for satellite on-orbit software according to any one of claims 1 to 4, 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.

7. The satellite-to-ground data transmission method for satellite on-orbit software according to claim 6, 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.

8. A system for the satellite-to-ground data transmission method for satellite on-orbit software according to any one of claims 1 to 7, 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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