Space application data preprocessing method and system based on CCSDS protocol

Abstract

The invention belongs to the field of data preprocessing, and provides a space application data preprocessing method and system based on a CCSDS protocol. The method comprises the following steps: calculating a forward jump array and a reverse jump array of a current layer data encapsulation format data synchronization identifier; the processing result of the upper layer is stored in a cache region, and search data synchronization identification is carried out in the cache region; the position where the first data synchronization identifier is found is recorded as pos1, the length len of the current data frame is obtained according to data length marks filled in main and auxiliary guide heads of the data frame, and the byte length of the data synchronization identifier is set as L; setting the appearing position of the data synchronization identifier of the next frame as E (pos) = pos1 + len, and searching the data synchronization identifier of the next frame by taking the E (pos) position as an expected position; performing data synchronization identifier matching at the position E (pos) + L = pos1 + lens + L, updating the position of the data synchronization identifier, and continuing to search the data synchronization identifier.

Description

Technical Field

[0001] The present invention belongs to the field of data preprocessing, and particularly relates to a method and system for preprocessing space application data based on the CCSDS protocol. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] In order to promote international cooperation and standardization in the field of aerospace and space applications, the Consultative Committee for Space Data System (CCSDS) has developed a series of space application data protocols; its protocol stack includes data transmission protocols at multiple levels such as the application layer, transport layer, network layer, data link layer, and physical layer. CCSDS member organizations formulate intra-organizational space application data transmission protocols based on the protocol architecture of CCSDS and design the data processing flow of the ground system accordingly. The basic processing flow experienced by the application data generated by space application payloads includes: (1) the payload data packetization and encryption processing flow on the flight system; (2) the physical layer transmission control and modulation / demodulation of the space-ground link; and (3) the data preprocessing of the ground system. Among them, the process of unpacking and sub-packing the data involved in the ground system and finally restoring it to the payload application data is called data preprocessing.

[0004] Currently, the main space-ground communication method is microwave communication, and its communication quality is greatly affected by factors such as weather and pointing. Since the space-ground transmission does not have the ability of two-way handshake communication and error retransmission similar to the TCP / IP protocol and the error correction ability of the link layer LDPC (Low-density Parity-check) is limited, the situation of transmission errors in the transmission link will exist widely. Based on the application scenario where the data volume increases rapidly and transmission errors exist widely, it is very important for the ground preprocessing to perform efficient frame synchronization operations and propose effective and reliable data frames. Traditional methods based on simple pattern matching will encounter many bottlenecks in processing speed. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method and system for preprocessing space application data based on the CCSDS protocol. For the frame synchronization operation of each data layer, it adopts a two-way retrieval mode, which can search in both forward and reverse directions at the expected position of the data synchronization identifier to reduce the matching range.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention provides a method for preprocessing space application data based on the CCSDS protocol.

[0008] In one or more embodiments, a method for preprocessing space application data based on the CCSDS protocol is provided, including:

[0009] Calculating the forward jump array and the reverse jump array of the data synchronization identifier of the current layer data encapsulation format;

[0010] Storing the processing result of the previous layer into the buffer area, and performing an operation of searching for the data synchronization identifier in the buffer area; recording the position where the first data synchronization identifier is found as pos1, obtaining the length len of the current data frame according to the data length flag filled in the main and secondary headers of the data frame, and setting the byte length of the data synchronization identifier as L; setting the position where the data synchronization identifier of the next frame appears as E(pos) = pos1 + len, and searching for the data synchronization identifier of the next frame with the E(pos) position as the expected position;

[0011] Performing data synchronization identifier matching first at the position of E(pos) + L = pos1 + len + L. If the data synchronization identifier is found during the reverse search process, update the data synchronization identifier and continue to search for the data synchronization identifier in the buffer area; otherwise, start a forward search from the E(pos) position, find the position of the data synchronization identifier of the next frame and update the data synchronization identifier, and continue to search for the data synchronization identifier in the buffer area.

[0012] As an implementation manner of the first aspect of the present invention, if the data synchronization identifier is found during the reverse search process, and the new data synchronization identifier position is set as pos2, if pos2 < E(pos), it indicates that there is a data packet loss / misframe in the previous layer, and there must be no valid data frames in the interval [pos1, pos2), and the matching process is directly exited.

[0013] As an implementation manner of the first aspect of the present invention, if the data synchronization identifier is found during the reverse search process, and the new data synchronization identifier position is set as pos2, if pos2 >= E(pos), there may be valid data frames in the interval [pos1, pos2), and extract and verify them.

[0014] As an implementation manner of the first aspect of the present invention, the current layer is a protocol layer, which corresponds to byte-level data.

[0015] As an implementation manner of the first aspect of the present invention, the current layer is an application layer, which corresponds to bit-level data.

[0016] The second aspect of the present invention provides a system for preprocessing space application data based on the CCSDS protocol.

[0017] In one or more embodiments, a space application data preprocessing system based on the CCSDS protocol includes:

[0018] A two-way jump array calculation module, which is used to calculate the forward jump array and the reverse jump array of the data synchronization identifier of the current layer data encapsulation format;

[0019] A data synchronization identifier search module, which is used to store the processing result of the previous layer into the buffer area and search for the data synchronization identifier in the buffer area; record the position where the first data synchronization identifier is found as pos1, obtain the current data frame length len according to the data length flag filled in the main and secondary headers of the data frame, and set the byte length of the data synchronization identifier as L; set the position where the data synchronization identifier of the next frame appears as E(pos) = pos1 + len, and search for the data synchronization identifier of the next frame with E(pos) as the expected position;

[0020] A data synchronization identifier matching module, which is used to first perform data synchronization identifier matching at the position of E(pos) + L = pos1 + len + L. If the data synchronization identifier is found during the reverse search process, update the data synchronization identifier and continue to search for the data synchronization identifier in the buffer area; otherwise, start a forward search from the E(pos) position, find the position of the data synchronization identifier of the next frame and update the data synchronization identifier, and continue to search for the data synchronization identifier in the buffer area.

[0021] As an implementation manner of the second aspect of the present invention, in the data synchronization identifier matching module, if the data synchronization identifier is found during the reverse search process, set the new data synchronization identifier position as pos2. If pos2 < E(pos), it means that there is a data packet loss / misframe in the previous layer, and there must be no valid data frames in the interval [pos1, pos2), and directly exit the matching process.

[0022] As an implementation manner of the second aspect of the present invention, in the data synchronization identifier matching module, if the data synchronization identifier is found during the reverse search process, set the new data synchronization identifier position as pos2. If pos2 >= E(pos), there may be valid data frames in the interval [pos1, pos2), extract and verify them.

[0023] The third aspect of the present invention provides a computer-readable storage medium.

[0024] A computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the steps in the above-mentioned space application data preprocessing method based on the CCSDS protocol.

[0025] The fourth aspect of the present invention provides an electronic device.

[0026] An electronic device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in the above-mentioned space application data preprocessing method based on the CCSDS protocol.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The present invention presets the starting position for searching for a data synchronization identifier according to the data frame length information filled in the main and secondary headers of the data. Through a two-way retrieval mode, it can search in both forward and reverse directions at the expected position of the data synchronization identifier to reduce the matching range. After matching the data synchronization identifier, for bit-level matching, it is only necessary to define the comparison operator between the pattern string and the matching string, and it can be easily extended to the bit level, realizing the formal unity of bit matching and byte matching and allowing flexible switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0030] Figure 1 is the basic protocol structure of CCSDS in the embodiments of the present invention;

[0031] Figure 2 is the space data transmission and ground processing flow in the embodiments of the present invention;

[0032] Figure 3 is a schematic flow chart of the space application data preprocessing method based on the CCSDS protocol in the embodiments of the present invention;

[0033] Figure 4 is the schematic diagram of the space application data preprocessing principle based on the CCSDS protocol at the protocol layer in the embodiments of the present invention;

[0034] Figure 5 is the schematic diagram of the space application data preprocessing principle based on the CCSDS protocol at the application layer in the embodiments of the present invention;

[0035] Figure 6 is the schematic diagram of the structure of the space application data preprocessing system based on the CCSDS protocol in the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0037] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the present invention belongs.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] The basic protocol structure of CCSDS is as Figure 1 shown, Figure 2 for the space data transmission and ground processing flow. The process of unpacking and sub-packing the data involved in the ground system in Figure 2 and finally restoring it to the payload application data is called data preprocessing.

[0040] Figure 3 is a schematic flow chart of a method for preprocessing space application data based on the CCSDS protocol in an embodiment of the present invention. As Figure 3 shown, the method for preprocessing space application data based on the CCSDS protocol in this embodiment may include:

[0041] S301, calculating the forward jump array and the reverse jump array of the data synchronization identifier of the current layer data encapsulation format;

[0042] S302, storing the processing result of the previous layer in the buffer area, and performing a search for the data synchronization identifier operation in the buffer area; recording the position where the first data synchronization identifier is found as pos1, obtaining the current data frame length len according to the data length flag filled in the main and secondary headers of the data frame, and setting the byte length of the data synchronization identifier as L; setting the position where the data synchronization identifier of the next frame appears as E(pos) = pos1 + len, and searching for the data synchronization identifier of the next frame with the E(pos) position as the expected position;

[0043] S303, first performing a data synchronization identifier match at the position of E(pos) + L = pos1 + len + L. If the data synchronization identifier is found during the reverse search process, update the data synchronization identifier and continue to search for the data synchronization identifier in the buffer area; otherwise, start a forward search from the E(pos) position, find the position of the data synchronization identifier of the next frame and update the data synchronization identifier, and continue to search for the data synchronization identifier in the buffer area.

[0044] In this embodiment, if a data synchronization identifier is found during the reverse search process, the position of the new data synchronization identifier is set to pos2. If pos2 < E(pos), it indicates that packet loss / frame error occurred in the previous layer, and there must be no valid data frames in the interval [pos1, pos2), and the matching process is directly exited.

[0045] If a data synchronization identifier is found during the reverse search process, the position of the new data synchronization identifier is set to pos2. If pos2 >= E(pos), there may be valid data frames in the interval [pos1, pos2), and they are extracted and verified.

[0046] In some embodiments, the current layer is the protocol layer, which corresponds to byte-level data, such as Figure 4 As shown, the algorithm pseudocode for the key process is as follows:

[0047] Step 1: Calculate the next array and the next_back array; assume the length of ASM is L, and the meaning of next[i] is the position to which the pointer i should jump after the mismatch between ASM[i + 1] and the corresponding byte in the cached data.

[0048] (1) Calculate the next array:

[0049] (1.1) Initialize the next array with next[0] = -1; and assign initial values to the double pointers i and j; i = 0, j = -1; at this time, next[i] = j;

[0050] (1.2) Control the double pointers i and j to traverse and complete the calculation of the jump array of the pattern string ASM

[0051] for(i = 0, j = -1; i < L; )

[0052] while(j!= -1 && ASM[i + 1]!= ASM[j + 1]) j = next[j];

[0053] if(j == -1) i++;

[0054] else next[++i] = ++j;

[0055] (2) Calculate the next_back array; the length of ASM is L, and next_back[i] represents the pointer value to which ASM[i] jumps after the mismatch with the cached character.

[0056] (2.1) First, next_back[L] = L + 1, and assign initial values to the double pointers i and j; i = L, j = L + 1; at this time, next[i] = j;

[0057] (2.2) The process of calculating the complete next_back array by controlling the double pointers i and j is as follows:

[0058] For (i = L, j = L + 1; i >= 0; )

[0059] While (j!= L + 1 && ASM[i - 1]!= ASM[j - 1]) j = next[j]

[0060] If (j == L + 1) i--;

[0061] else next[--i] = --j;

[0062] Step 2: Perform forward matching of data. The specific process is as follows:

[0063] Control the double pointers i and j to point to the bytes to be matched in the buffer array and ASM respectively. The algorithm process is as follows:

[0064] a) Assume the length of the buffer is N and the length of ASM is L.

[0065] Initialize i = 0, j = 0;

[0066] for (i = 0, j = 0; i < N; )

[0067] If (j == L) return i - j; / / Return the position where the match is successful

[0068] If (j == -1 || buffer[i] == ASM[j]) i++, j++;

[0069] else j = next[j];

[0070] b) Assume the position returned by the above process is recorded as pos. Obtain the frame length len according to the filling information in the leading header; Set the starting position for searching the next ASM as E(pos) = pos + len.

[0071] Step 3: Synchronize the data frame at the expected position E(pos) where ASM appears. First, perform a reverse search of the data.

[0072] a) Perform a reverse search at the position pos1 = E(pos) + L, and the search range is [pos, pos1];

[0073] for (i = pos1, j = L, i >= pos; )

[0074] If (j == -1) return i; / / Return the position record pos2 of the new ASM

[0075] if (j == L + 1 || arr[i] == head[j]) i--; j--;

[0076] else j = next[j]

[0077] b) If there is no return in the above reverse search process, it means no match is found. A forward search should be performed at the position of E(pos) - L. The specific process is the same as in Step 2. The position of the second-frame ASM obtained by matching is pos2. If pos2 - pos1 >= len, then extract the valid data frame in [pos1, pos1 + len) and perform subsequent verification and processing.

[0078] Step 4: Let pos = pos2 and repeat Step 2 and Step 3

[0079] In some other embodiments, the current layer is the application layer, which corresponds to bit-level data, as Figure 5 shown.

[0080] The main steps for bit-frame synchronization in the application layer are as follows:

[0081] Step 1: Convert the ASM into a bit-level synchronization identifier and convert it into a boolean array ASM_bit.

[0082] for (bitIndex = 0; bitIndex < 8 * L; bitIndex++)

[0083] Mask = 1 << (7 - bitIndex & 7)

[0084] ASM_bit[bitIndex] = ASM[bitIndex >> 3] & Mask

[0085] Step 2: Calculate the next array and next_back data based on ASM_bit. The meaning of next[bitIndex] is the bit position to which it should jump if the bitIndex-th bit of ASM fails to match.

[0086] for (i = 0, j = -1; i < 8 * L;)

[0087] while (j!= -1 && ASM_bit[i + 1]!= ASM_bit[j + 1]) j = next[j];

[0088] if (j == -1) i++;

[0089] else next[++i] = ++j;

[0090] The pseudo-code for calculating the next_back array is as follows:

[0091] for(i = 8*L, j = 8*L + 1; i >= 0; )

[0092] While(j != 8*L + 1 && ASM_bit[i - 1] != ASM_bit[j - 1]) j = next_back[j]

[0093] if(j == 8*L + 1) i--;

[0094] else next[--i] = --j;

[0095] Step 3: Match the data matching string and the pattern string, where the matching algorithm is the same. The key thing to focus on is the redefined comparison function. Let there be two pointers i and j pointing to the matching string and the pattern string respectively. Define the following operation rules

[0096] bitOpASM(j) = ASM[j >> 3] & (1 << (7 - j & 7))

[0097] bitOpBuffer(i) = buffer[i >> 3] & (i << (7 - i & 7))

[0098] Bool comp(I, j) = ~(bitOpASM(i) ^ bitOpBuffer(j))

[0099] where i and j represent the i-th bit and the j-th bit in the target data and the pattern string respectively. If cmp(i, j) is true, the bit at the current position is matched; otherwise, it needs to backtrack according to the next or next_back array. The value range of j is [0, 8*L]. When j == 8*L during the forward matching process or j == -1 during the reverse matching process, it means that ASM matches successfully in the bit buffer of the application data. The data extraction process is the same as that in Section 4.1.

[0100] The pseudo-code for the forward matching process is as follows:

[0101] for(i = 0, j = 0; i < N; )

[0102] If(j == 8*L) return i - j; / / Return the position where the match is successful

[0103] If(j == -1 || cmp(i, j) == true) i++, j++;

[0104] else j = next[j];

[0105] The pseudo-code for the reverse matching process is:

[0106] for(i = E(pos), j = 8 * L, i >= pos;)

[0107] If(j == -1) return i; / / Return the position record pos2 of the new ASM

[0108] if(j == 8 * L + 1 || cmp(i, j) == true) i--; j--;

[0109] else j = next[j]

[0110] The KMP (Knuth - Morris - Pratt) algorithm is a search algorithm for solving the text string matching problem. Its greatest advantage lies in that the time complexity of its matching is o(n). Data frame synchronization is the basis for data pre - processing in the ground system. The ground processing software needs to delimit the data frame through the ASM (Attached Sync Mark) before processing the CCSDS data frame. In this invention, the KMP algorithm is effectively applied in the data frame synchronization link and further modified according to the characteristics of the data frame encapsulation stipulated in the CCSDS protocol stack, so that the synchronization operation of the data frame has a higher rate and can effectively meet the processing requirements of the space application data with rapid growth. It can be seen from the above algorithm process that in this link, only a bit comparison function for the pattern string and the matching string is newly defined, and the matching process is extended from the byte level to the bit level. Moreover, the jump position can be obtained by looking up the table in the next array, which greatly improves the efficiency. Compared with the traditional method of bit - by - bit comparison, the efficiency is increased by up to 8 * L times.

[0111] Figure 6 It is a schematic structural diagram of a space application data pre - processing system based on the CCSDS protocol in an embodiment of the present invention. This embodiment corresponds to Figure 3 the space application data pre - processing method based on the CCSDS protocol, as Figure 6 shown, the space application data pre - processing system based on the CCSDS protocol in this embodiment may include:

[0112] A two - way jump array calculation module 601, which is used to calculate the forward jump array and the reverse jump array of the data synchronization identifier in the current - layer data encapsulation format;

[0113] The data synchronization flag search module 602 is used to store the processing result of the upper layer in the buffer area and perform the operation of searching for the data synchronization flag in the buffer area; record the position where the first data synchronization flag is found as pos1, obtain the current data frame length len according to the data length flag filled in the main and secondary headers of the data frame, and set the byte length of the data synchronization flag as L; set the position where the data synchronization flag of the next frame appears as E(pos) = pos1 + len, and search for the data synchronization flag of the next frame with the position of E(pos) as the expected position;

[0114] The data synchronization flag matching module 603 is used to first perform data synchronization flag matching at the position of E(pos) + L = pos1 + len + L. If the data synchronization flag is found during the reverse search process, update the data synchronization flag and continue to search for the data synchronization flag in the buffer area; otherwise, start a forward search from the position of E(pos), find the position of the data synchronization flag of the next frame and update the data synchronization flag, and continue to search for the data synchronization flag in the buffer area.

[0115] Among them, in the data synchronization flag matching module 603, if the data synchronization flag is found during the reverse search process, set the new data synchronization flag position as pos2. If pos2 < E(pos), it means that there is a packet loss / frame error in the upper layer, and there must be no valid data frames in the interval [pos1, pos2), and directly exit the matching process.

[0116] In the data synchronization flag matching module 603, if the data synchronization flag is found during the reverse search process, set the new data synchronization flag position as pos2. If pos2 >= E(pos), there may be valid data frames in the interval [pos1, pos2), extract and verify them.

[0117] It should be noted here that Figure 6 each module in the space application data preprocessing system based on the CCSDS protocol in Figure 3 corresponds one by one to each step in the space application data preprocessing method based on the CCSDS protocol in

[0118] In one or more embodiments, the electronic device includes a central processing unit (CPU), which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) or the program loaded from the storage part into the random access memory (RAM). In the RAM, various programs and data required for system operation are also stored. The central processing unit, ROM, and RAM are connected to each other through a bus. The input / output (I / O) interface is also connected to the bus.

[0119] The following components are connected to the I / O interface: an input part including a keyboard, a mouse, etc.; an output part including a cathode ray tube (CRT), a liquid crystal display (LCD), etc. and a speaker, etc.; a storage part including a hard disk, etc.; and a communication part including a network interface card such as a local area network (LAN) card, a modem, etc. The communication part performs communication processing via a network such as the Internet. A drive is also connected to the I / O interface as needed. Removable media such as magnetic disks, optical discs, magneto-optical discs, semiconductor memories, etc. are installed on the drive as needed so that computer programs read from them are installed into the storage part as needed.

[0120] When the central processing unit in the electronic device of this embodiment executes the program, it implements the steps in the space application data preprocessing method based on the CCSDS protocol as Figure 3 shown.

[0121] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program codes for executing Figure 3 the method shown. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part, and / or installed from the removable medium. When the computer program is executed by the central processing unit, various functions defined in the device of the present application are executed.

[0122] Among them, Figure 3 the computer program instructions corresponding to the method shown can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one process or multiple processes and / or Figure 1 one block or multiple blocks.

[0123] Those of ordinary skill in the art can understand that to implement all or part of the processes in the above-described embodiment methods, it can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-described methods. Among them, the storage medium can be a magnetic disk, an optical disc, a read-only memory (ROM), or a random access memory (RAM), etc.

[0124] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A spatial application data preprocessing method based on the CCSDS protocol, characterized in that: Including: Calculating the forward jump array and the reverse jump array of the data synchronization identifier for the data encapsulation format of the current layer; Storing the processing result of the previous layer in the buffer and performing an operation to search for the data synchronization identifier in the buffer; Recording the position where the first data synchronization identifier is found as pos1, obtaining the current data frame length len based on the data length flag filled in the main and secondary headers of the data frame, and setting the byte length of the data synchronization identifier as L; setting the position where the data synchronization identifier of the next frame appears as E(pos) = pos1 + len, and searching for the data synchronization identifier of the next frame with the E(pos) position as the expected position; First performing data synchronization identifier matching at the position of E(pos) + L = pos1 + len + L. If the data synchronization identifier is found during the reverse search process, updating the data synchronization identifier and continuing to search for the data synchronization identifier in the buffer; otherwise, starting a forward search from the E(pos) position, finding the position of the data synchronization identifier of the next frame and updating the data synchronization identifier, and continuing to search for the data synchronization identifier in the buffer.

2. The spatial application data preprocessing method based on the CCSDS protocol according to claim 1, characterized in that: If the data synchronization identifier is found during the reverse search process, setting the new data synchronization identifier position as pos2. If pos2 < E(pos), it indicates that there is a packet loss / frame error in the previous layer, and there must be no valid data frames in the interval [pos1, pos2), and the matching process is directly exited.

3. The spatial application data preprocessing method based on the CCSDS protocol according to claim 1, characterized in that: If the data synchronization identifier is found during the reverse search process, setting the new data synchronization identifier position as pos2. If pos2 >= E(pos), there may be valid data frames in the interval [pos1, pos2), and they are extracted and verified.

4. The spatial application data preprocessing method based on the CCSDS protocol according to claim 1, characterized in that: The current layer is a protocol layer, corresponding to byte-level data.

5. The spatial application data preprocessing method based on the CCSDS protocol according to claim 1, characterized in that: The current layer is an application layer, corresponding to bit-level data.

6. A space application data preprocessing system based on CCSDS protocol, characterized in that: Including: A bidirectional jump array calculation module, which is used to calculate the forward jump array and the reverse jump array of the data synchronization identifier for the data encapsulation format of the current layer; A data synchronization identifier search module, which is used to store the processing result of the previous layer in the buffer and perform an operation to search for the data synchronization identifier in the buffer; Recording the position where the first data synchronization identifier is found as pos1, obtaining the current data frame length len based on the data length flag filled in the main and secondary headers of the data frame, and setting the byte length of the data synchronization identifier as L; setting the position where the data synchronization identifier of the next frame appears as E(pos) = pos1 + len, and searching for the data synchronization identifier of the next frame with the E(pos) position as the expected position; A data synchronization identifier matching module, which is used to first perform data synchronization identifier matching at the position of E(pos) + L = pos1 + len + L. If the data synchronization identifier is found during the reverse search process, updating the data synchronization identifier and continuing to search for the data synchronization identifier in the buffer; otherwise, starting a forward search from the E(pos) position, finding the position of the data synchronization identifier of the next frame and updating the data synchronization identifier, and continuing to search for the data synchronization identifier in the buffer.

7. The space application data preprocessing system based on the CCSDS protocol as claimed in claim 6, characterized in that: In the data synchronization flag matching module, if a data synchronization flag is found during the reverse search, set the position of the new data synchronization flag as pos2. If pos2 < E(pos), it indicates that packet loss / frame error occurs in the upper layer, and there must be no valid data frames in the interval [pos1, pos2), and directly exit the matching process.

8. The space application data preprocessing system based on the CCSDS protocol as claimed in claim 6, characterized in that: In the data synchronization flag matching module, if a data synchronization flag is found during the reverse search, set the position of the new data synchronization flag as pos2. If pos2 >= E(pos), there may be valid data frames in the interval [pos1, pos2), and extract and verify them.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, it implements the steps in the space application data preprocessing method based on the CCSDS protocol described in any one of claims 1-5.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, it implements the steps in the space application data preprocessing method based on the CCSDS protocol described in any one of claims 1-5.

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