CN117478203A - Solidified satellite-borne CAN bus communication system - Google Patents

Abstract

A solidified on-board CAN bus communication system comprises a master node and at least one slave node, wherein data are transmitted between the master node and the slave nodes through a CAN bus. The communication protocol is realized by adopting a CCSDS packet protocol and a non-packet customized protocol together, and for data with the byte number not more than 6 bytes, the non-packet customized single frame protocol is selected; both telemetry data and remote control instructions having a byte count greater than 6 bytes are in a CCSDS packet format. According to the invention, the solidified on-board CAN bus communication application layer is introduced to form the standard of the on-board network transmission protocol, so that the universal use of different types is realized, the solidified part CAN be directly applied, the workload of on-board equipment bus communication design test is reduced, and the efficiency of component joint test and whole-satellite test is improved. The packets transmitted on the CAN bus adopt a more general CCSDS packet format, so that transparent transmission of data is realized, a master-slave one-to-one communication waiting mode is broken, response time of slave nodes is widened, and transmission efficiency is improved when a machine is saved.

Description

Solidified satellite-borne CAN bus communication system

Technical Field

The invention belongs to the technical field of satellite communication, and relates to a satellite communication system based on a CAN bus, which CAN realize solidification on an FPGA/ASIC/CPU.

Background

In recent years, spacecraft, especially small satellites, are rapidly developed, the number of on-orbit satellites is rapidly increased, functions are more and more powerful, and the requirements on satellite-borne CAN bus communication are higher and higher. The current satellite-borne CAN bus communication has a plurality of problems, and the actual requirements are difficult to meet.

First, the CAN bus application layer communication protocol definition is not standard enough and cannot be commonly used. The current CAN bus standard only provides for a physical layer and a data link layer, the application layer protocol of the satellite-borne CAN bus is mainly model-customized, and the whole satellite interface joint test workload is large.

Secondly, the allocation designs of the CAN bus lower computer station addresses, the shielding codes and the like are not flexible enough, a designer needs to allocate the station addresses according to the specific receiving and transmitting data requirements of each lower computer, the shielding code design also needs to select an optimal scheme in the arrangement of a plurality of different station addresses, and the complexity of the design process is high.

Further, in the case of a limited bus code rate, an increase in the amount of data interaction is required to improve the bus utilization. For communication between master nodes and slave nodes, a one-to-one communication mode of polling, response and judgment is mostly adopted at present, and when a large number of master node CPU machines are occupied, the communication efficiency is low.

Finally, the current CAN bus communication has higher response time requirements on the slave nodes, if the generation time intervals of different data types of the slave nodes are larger, the master node is required to carry out additional time-sharing design on the polling of the slave nodes, the polling time sequences of different types are required to be specially customized, and the software design complexity is increased.

In summary, the application data types and the data volumes of the communication channels of the on-board network are more and more, and a standard general communication protocol and a high-efficiency flexible and simple logic communication system are needed to support the data transmission of multiple types, large capacity and multiple users.

Disclosure of Invention

The invention solves the technical problems that: aiming at the problems that the current satellite-borne CAN bus communication has various protocols, high complexity of station address/shielding word design, low communication efficiency, excessive occupation of a main node machine and the like, the transmission requirements of a plurality of satellite-borne network nodes and large data volume cannot be met, the solidified satellite-borne CAN bus communication system is provided, and CAN be realized in an FPGA/ASIC/CPU, so that the communication transmission efficiency is improved, and the logic design is simplified.

The technical scheme of the invention is as follows: a solidified satellite-borne CAN bus communication system comprises a master node and at least one slave node, wherein data transmission is carried out between the master node and the slave nodes through a CAN bus; the CAN bus communication protocol is realized by adopting a CCSDS packet protocol and a non-packet customized protocol together, and for data with the byte number not more than 6 bytes, a non-packet customized single frame protocol is selected; and the CCSDS packet format is adopted for the telemetry data with the byte number larger than 6 bytes and the remote control command transmission, so that the transparent transmission of the telemetry data acquisition and the remote control command distribution is realized.

Further, the single frame transmission format of the non-packet customized protocol includes an arbitration field, a control field, and an effective data field, wherein the arbitration field and the control field each occupy 1 byte, and the effective data field includes at most 6 bytes of effective data.

Further, the master node comprises a master node bus communication solidification layer and a master node data processing module, and the slave node comprises a slave node bus communication solidification layer and a slave node data processing module; the master node data processing module is used for receiving an external remote control instruction and forming remote control polling data, and forming remote control polling data of the slave node at the same time; the master node bus communication solidified layer is used for forming a remote control polling data packet and a remote measurement polling data packet which are sent by the master node to the slave node; the slave node data processing module is used for forming self remote sensing response data and remote sensing response data after the remote sensing polling data is executed, and the slave node bus communication solidifying layer is used for forming a remote sensing response data packet and a remote sensing response data packet which are sent from the slave node to the master node; and the master node bus communication solidified layer and the slave node bus communication solidified layer transmit data packets according to the CAN bus communication protocol.

Furthermore, the master node bus communication solidified layer and the slave node bus communication solidified layer are realized by adopting an FPGA, a CPU or an ASIC.

Further, the main node data processing module comprises a configuration parameter unit, a telemetry polling packet unit, a remote control frame receiving unit, a remote control polling packet unit, a response data packet framing unit, a telemetry frame sending unit and a response state updating unit; the configuration parameter unit sends the station addresses of the master node and the slave nodes, the polling data type of each slave node, the bus code rate and the shielding word to the bus communication solidified layer of the master node to initialize bus communication; after initialization is completed, the remote control frame receiving unit receives a remote control data frame through an external remote control interface, and the remote control polling packet unit extracts a remote control polling packet from the remote control data frame; simultaneously, a telemetry polling group packet unit prepares a telemetry polling packet of the slave node, and both the telemetry polling packet and the telemetry polling packet are sent to a bus communication solidification layer of the master node; the response state updating unit matches corresponding polling according to the APID in the packet identification, sets the response state of the polling to be closed, updates the response type and the number of times, and finishes remote control data communication when the response type is remote control; when the response type is remote, the response data packet framing unit extracts the telemetry data from the response data packet which passes through the interpretation to carry out framing, and the telemetry frame transmitting unit transmits the framed telemetry data to an external telemetry interface.

Further, the master node mask word is set to be all recessive, all is logic 1, and an address with recessive bit not less than 4 is selected as the slave node station address.

Further, the main node bus communication solidification layer comprises a bus initialization unit, a polling packet FIFO unit, a polling packet sending unit, a response packet receiving unit, a response data interpretation unit and a bus fault tolerance management unit; the bus initialization unit performs bus communication initialization according to the parameters transmitted by the configuration parameter unit in the main node data processing module, the polling packet FIFO unit performs remote control polling packet and remote measurement polling packet storage, the polling packet transmitting unit extracts the polling packet from the polling packet FIFO unit, frames according to the CAN bus communication protocol, and transmits the polling packet to the CAN bus; the response data receiving unit receives response data frames of the slave nodes from the CAN bus, judges whether the response data frames are received completely according to the frame format, and puts the response data frames into the response data judging unit to judge the frame format and the CCSDS packet format of the effective data field after the response data frames are received completely, and the judging state is sent to the bus fault tolerance management unit; if the judging states received by the bus fault-tolerant management unit are all passed, judging that the response data is valid; otherwise, judging that the response data is invalid, and executing bus reset operation; the bus fault tolerance management unit sends the effective data, the interpretation state and the execution operation to the response state updating unit in the main node data processing module.

Further, the slave node bus communication solidification layer comprises a bus initialization unit, a bus fault tolerance management unit, a polling packet receiving unit, a format interpretation unit, a response buffer unit and an automatic response packet sending unit; the bus initialization unit performs bus communication initialization according to the received parameters, and after the initialization is completed, the receiving polling packet unit receives a data frame from the CAN bus based on the CAN bus communication protocol and sends the data frame to the format interpretation unit; the format interpretation unit interprets the data frame format and the CCSDS packet format of the effective data field, and the interpretation state is sent to the bus fault tolerance management unit; if the judging states received by the bus fault-tolerant management unit are all passed, judging that the polling data is valid; otherwise, judging that the polling data is invalid, and executing bus reset operation; the bus fault tolerance management unit sends effective data, interpretation state and execution operation to the slave node data processing module; the response buffer unit receives response data from the slave node data processing module, and when the response identifier is valid, the automatic response packet sending unit reads the response data framing from the response buffer unit and sends the response data framing to the CAN bus, and the post response identifier is invalid after the transmission is finished.

Further, the slave node data processing module comprises a configuration parameter unit, a polling state updating unit, a remote control data executing unit and a response data generating unit; the configuration parameter unit sends the station address, the polling data type, the bus code rate and the shielding word of the node to a bus initialization unit in the slave node bus communication solidified layer for bus initialization; the polling state updating unit updates the polling state according to the parameters transmitted from the bus fault tolerance management unit in the node bus communication solidification layer, wherein the polling state updating unit comprises a polling type, a polling interpretation state and polling times; the remote control data execution unit executes related operations according to the content of remote control polling data packets, generates response data packets and sends the response data packets to a response buffer unit in a slave node bus communication solidified layer; if the remote measurement polling is carried out, setting a response mark as effective and sending the response mark to an automatic response sending packet unit in a slave node bus communication solidified layer; and the response data generating unit generates telemetry response data according to the time sequence of the node self-function algorithm, and stores the telemetry response data into a response buffer zone unit in the slave node bus communication solidified layer.

Further, the slave node shielding words are set to be all recessive and all logic 1, and the slave node filters unnecessary data according to station address filtering and packet master header APID filtering continuous secondary filtering.

Compared with the prior art, the invention has the advantages that:

(1) The packets transmitted on the CAN bus adopt a more universal CCSDS packet format, realize transparent transmission of telemetry and remote control and bus data, support long packet transmission and consider the flexibility and reliability of bus communication;

(2) The design of the CAN bus node station address selection classification, the shielding code and the hierarchical filtering ensures that the station address allocation and the shielding code arrangement are simple and clear, and the design complexity of the data stream is greatly reduced;

(3) In the bus communication system of the invention, the master node designs a data packet FIFO and a response buffer area, and only requires the slave node data to respond in a configured period. In the response data interpretation submodule, the transmitted data packet FIFO and response data are compared one by one, and after successful pairing, the data packet FIFO and the response data are put into a response buffer area, a one-to-one communication waiting mode of a master node and a slave node is broken, response time of a slave node is widened, and transmission efficiency is improved when a machine is saved;

(4) In the bus communication system, the data generation and response of the slave node are stripped, the data can be put into a response buffer area when being generated, and the latest data is automatically responded when the master node polls a data packet; the master node does not need to poll at intervals, so that the logic complexity is reduced;

(5) According to the invention, by introducing a solidified on-board CAN bus communication application layer design, an on-board network transmission protocol standard is formed, the universality of different types is realized, the solidifying part CAN be directly applied, the on-board equipment bus communication design test workload is reduced, and the component joint test and whole-board test efficiency is improved.

Drawings

FIG. 1 is a block diagram of the principles of the system of the present invention;

FIG. 2 is a schematic diagram of the CAN bus protocol of the present invention for implementing transparent transmission;

FIG. 3 is a flow chart of the CAN bus telemetry data communication of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 1, a schematic block diagram of a solidified on-board CAN bus communication system according to the present invention mainly includes a master communication node (abbreviated as master node) and at least one slave communication node (abbreviated as slave node), where the master node further includes a master node bus communication solidified layer and a master node data processing module. The slave node further comprises a slave node bus communication solidified layer and a slave node data processing module. And data transmission is performed between the master node and the slave node mainly through a CAN bus between the master node bus communication solidified layer and the slave node bus communication solidified layer.

The main node data processing module further comprises a configuration parameter unit, a remote measurement polling packet unit, a remote control frame receiving unit, a remote control polling packet unit, a response data packet framing unit, a remote measurement frame transmitting unit and a response state updating unit. The main node bus communication solidifying layer further comprises a bus initializing unit, a polling packet FIFO unit, a polling packet sending unit, a response packet receiving unit, a response data judging unit and a bus fault tolerance management unit. The solidified layer may be implemented by FPGA/ASIC/CPU.

Firstly, the configuration parameter unit sends the station address of the master/slave node, the polling data type of each slave node, the bus code rate, the mask word and other parameters to the bus initializing unit, and the bus initializing unit performs bus communication initialization according to the received parameters.

The master node mask word is set to be all recessive (logic 1 indicates that all data are received), and an address with more recessive (logic 1) bits (more than or equal to 4) is selected as the address of the slave node station, so that the slave node can conveniently receive and transmit broadcast.

After initialization is completed, the remote control frame receiving unit receives a remote control data frame through an external remote control interface, and the remote control polling packet unit extracts a remote control polling packet from the remote control data frame; simultaneously, the telemetry polling packet unit prepares a telemetry polling packet of the slave node, the remote control polling packet and the telemetry polling packet (collectively referred to as polling packets) are sent to the polling packet FIFO unit for storage, the transmission polling packet unit extracts the polling packet from the polling packet FIFO unit, frames according to a CAN bus communication protocol, and transmits the polling packet to a CAN bus.

The CAN bus communication protocol is jointly realized by adopting a CCSDS packet protocol and a non-packet customized protocol, and for data with fewer bytes (less than or equal to 6 bytes) (such as 4-byte instructions, 6-byte time broadcasting and the like), the non-packet customized single-frame protocol is selected (table 1); other data (telemetry data and remote control commands greater than 6 bytes) transmissions all take the form of CCSDS packets. Wherein the single frame transmission CCSDS packet format is shown in table 2 and the multi-frame transmission CCSDS packet format is shown in table 3.

In tables 1 to 3, only the effective data field content is different, the transmission content of the CCSDS packet format consists of a 6-byte master header and a data field, wherein the definition of the 6-byte master header is shown in table 4, and the data field can be divided into a secondary header, effective content and a checksum. In the case of the data in table 3 being multi-frame, the first byte Index in the valid data field is high by 2 bits to identify the first frame (01 b), the last frame (10 b) and the intermediate frame (00 b), and low by 6 bits to be used for the cycle count.

Table 1 non-packet formatted single frame transmission

Table 2CCSDS packet format single frame transmission

Table 3CCSDS packet format multiframe transmission

Table 4CCSDS packet Format definition

The bus data communication adopts CCSDS packet format, and can realize the transparent transmission of telemetry data acquisition and remote control command distribution. Taking telemetry data acquisition as an example, as shown in fig. 2, a common transmission processing flow is that firstly, effective data is intercepted from a bus transmission frame according to a transmission protocol, and the effective data is spliced (multi-frame); then, according to the slave node identification, the length and the like, filling the data packet header, calculating a packet checksum; and finally, putting the whole packet of data into a telemetry frame data field. The transparent transmission process under the packet format is to directly read the whole packet data from the bus transmission frame, put the whole packet data into the telemetry frame data field for framing and downloading, and the main node is not required to process.

The slave node bus communication solidifying layer further comprises a bus initializing unit, a bus fault tolerance management unit, a polling packet receiving unit, a format judging unit, a response buffer unit and an automatic response packet sending unit. The slave node data processing module further comprises a configuration parameter unit, a polling state updating unit, a remote control data executing unit and a response data generating unit.

Firstly, the configuration parameter unit sends the station address, the polling data type, the bus code rate, the shielding word and other parameters of the node to the bus initializing unit, and the bus initializing unit initializes the bus communication according to the received parameters. The slave node mask is set to all implicit (logic 1, all data received) and the slave node filters out unwanted data based on station address filtering (first stage filtering), packet master pilot APID filtering (second stage filtering).

After the initialization is completed, the receiving and polling packet unit receives the data frame from the CAN bus based on the bus communication protocol, and sends the data frame to the format interpretation unit after secondary filtering. The format interpretation unit performs the interpretation of the data frame format (arbitration field, control field, frame number, checksum, etc.) and the CCSDS packet format of the valid data field (packet identification, packet length, accumulation sum, etc.), and the interpretation status is sent to the bus fault tolerance management unit.

The fault-tolerant management unit judges that the polling data is valid if the judging states are all received, and clears the error count (accumulation); otherwise, the polling data is determined to be invalid, and a bus reset operation is performed according to the type of error in the interpretation state and the count value (accumulated or not). The bus fault-tolerant management unit sends effective data, an interpretation state, an execution operation and the like to the polling state updating unit, and the polling state updating unit updates the polling state at this time, wherein the polling state updating unit comprises a polling type (remote control or remote measurement), a polling interpretation state, a polling frequency and the like.

The remote control data execution unit executes related operations according to the content of the remote control polling data packet, generates a response data packet and sends the response data packet to the response buffer area unit; if the remote measurement polling is performed, the response identification is set to be valid, and the immediate response to the polling is not required.

The response data generating unit generates telemetry response data according to the time sequence of the node self-function algorithm, stores the telemetry response data in the response buffer area unit, and when the response identification is valid, the automatic response packet transmitting unit reads the response data from the response buffer area unit, frames and transmits the response data, and after the transmission is finished, the response identification is invalid.

The receiving response packet unit of the master node receives the response data frame of the slave node from the CAN bus, judges whether the receiving is finished according to the CAN frame format (tail frame), and puts the response data frame into the response data judging unit to judge the CCSDS packet format of the CAN frame format (arbitration field, control field, frame number, checksum and the like) and the effective data field (packet identification, packet length, accumulation sum and the like) after the receiving is finished, and the judging state is sent to the bus fault tolerance management unit.

If the judging states received by the bus fault-tolerant management unit are all passed, judging that the response data is valid, and clearing error counting (accumulation); otherwise, the answer data is determined to be invalid, and a bus reset operation is performed according to the type of error in the interpretation state and the count value (accumulation or non-accumulation). The bus fault-tolerant management unit sends effective data, interpretation state, execution operation and the like to the response state updating unit, and the response state updating unit is required to match corresponding polling according to the APID (table 4) in packet identification because the master communication and the slave communication are not in a one-to-one waiting mode, the current polling response state is set to be closed, the response type, the number of times and other states are updated, and when the response type is remote control, the remote control data communication is ended. When the response type is remote, the response data packet framing unit extracts the remote measurement data from the response data packet which is interpreted by the response data, framing is carried out, the remote measurement frame sending unit sends the remote measurement data to an external remote measurement interface, and the remote measurement data communication is finished.

Taking telemetry data as an example, as shown in fig. 3, a specific communication process of the system of the present invention is:

(1) Initializing a master node bus and a slave node bus;

(2) The main node packs the telemetry polling data and sends the telemetry polling data to a polling packet FIFO unit;

(3) The main node solidification layer reads the data packet from the FIFO, frames according to the CAN bus protocol, and sends a polling packet to the CAN bus;

(4) After receiving the polling data packet, the slave node performs CAN frame format (arbitration field, control field, frame number, checksum, etc.) and CCSDS packet format interpretation (packet identification, packet length, accumulation sum, etc.) of the effective data field, and the interpretation state and data perform bus fault tolerance management, polling state update and the response mark is valid;

(5) After the slave communication node data processing layer generates response data according to the self-function algorithm time sequence, storing the response data into a response buffer area, and transmitting the response data by the response buffer area when the response mark is valid, wherein the response mark is invalid after the transmission is finished;

(6) The main node receives response data and puts the response data into a response buffer zone, judges whether the receiving is finished according to a CAN frame format (tail frame), judges the CAN frame format (arbitration field, control field, frame sequence number, checksum and the like) and CCSDS packet format judging (packet identification, packet length, accumulation sum and the like) of an effective data field after the receiving is finished, and the main node needs to match corresponding polling according to an APID (table 4) in the packet identification, sets the polling response state as closed, and carries out bus fault tolerance management and response state updating on judging state and data;

(7) And the main node directly puts the response data packet in the CCSDS format into a telemetry frame data field, and the telemetry frame is sent to a telemetry interface, so that telemetry data communication is finished.

What is not described in detail in the present specification is a well known technology to those skilled in the art.

Claims (10)

1. A solidified on-board CAN bus communication system, characterized by: the system comprises a master node and at least one slave node, wherein data transmission is carried out between the master node and the slave nodes through a CAN bus; the CAN bus communication protocol is realized by adopting a CCSDS packet protocol and a non-packet customized protocol together, and for data with the byte number not more than 6 bytes, a non-packet customized single frame protocol is selected; and the CCSDS packet format is adopted for the telemetry data with the byte number larger than 6 bytes and the remote control command transmission, so that the transparent transmission of the telemetry data acquisition and the remote control command distribution is realized.

2. A solidified on-board CAN bus communication system according to claim 1, characterized in that: the single frame transmission format of the non-packet customized protocol comprises an arbitration field, a control field and an effective data field, wherein the arbitration field and the control field occupy 1 byte respectively, and the effective data field comprises 6 bytes of effective data at most.

3. A solidified on-board CAN bus communication system according to claim 1 or 2, characterized in that: the master node comprises a master node bus communication solidification layer and a master node data processing module, and the slave node comprises a slave node bus communication solidification layer and a slave node data processing module; the master node data processing module is used for receiving an external remote control instruction and forming remote control polling data, and forming remote control polling data of the slave node at the same time; the master node bus communication solidified layer is used for forming a remote control polling data packet and a remote measurement polling data packet which are sent by the master node to the slave node; the slave node data processing module is used for forming self remote sensing response data and remote sensing response data after the remote sensing polling data is executed, and the slave node bus communication solidifying layer is used for forming a remote sensing response data packet and a remote sensing response data packet which are sent from the slave node to the master node; and the master node bus communication solidified layer and the slave node bus communication solidified layer transmit data packets according to the CAN bus communication protocol.

4. A solidified on-board CAN bus communication system according to claim 3, characterized in that: the master node bus communication solidification layer and the slave node bus communication solidification layer are realized by adopting an FPGA, a CPU or an ASIC.

5. A solidified on-board CAN bus communication system according to claim 3, characterized in that: the main node data processing module comprises a configuration parameter unit, a remote sensing polling packet unit, a remote control frame receiving unit, a remote control polling packet unit, a response data packet framing unit, a remote sensing frame transmitting unit and a response state updating unit; the configuration parameter unit sends the station addresses of the master node and the slave nodes, the polling data type of each slave node, the bus code rate and the shielding word to the bus communication solidified layer of the master node to initialize bus communication; after initialization is completed, the remote control frame receiving unit receives a remote control data frame through an external remote control interface, and the remote control polling packet unit extracts a remote control polling packet from the remote control data frame; simultaneously, a telemetry polling group packet unit prepares a telemetry polling packet of the slave node, and both the telemetry polling packet and the telemetry polling packet are sent to a bus communication solidification layer of the master node; the response state updating unit matches corresponding polling according to the APID in the packet identification, sets the response state of the polling to be closed, updates the response type and the number of times, and finishes remote control data communication when the response type is remote control; when the response type is remote, the response data packet framing unit extracts the telemetry data from the response data packet which passes through the interpretation to carry out framing, and the telemetry frame transmitting unit transmits the framed telemetry data to an external telemetry interface.

6. The solidified satellite-borne CAN bus communication system of claim 5, further comprising: the master node shielding word is set to be totally hidden, all are logic 1, and an address with a hidden bit not less than 4 is selected as a slave node station address.

7. The solidified satellite-borne CAN bus communication system of claim 5, further comprising: the main node bus communication solidifying layer comprises a bus initializing unit, a polling packet FIFO unit, a polling packet sending unit, a response packet receiving unit, a response data judging unit and a bus fault tolerance management unit; the bus initialization unit performs bus communication initialization according to the parameters transmitted by the configuration parameter unit in the main node data processing module, the polling packet FIFO unit performs remote control polling packet and remote measurement polling packet storage, the polling packet transmitting unit extracts the polling packet from the polling packet FIFO unit, frames according to the CAN bus communication protocol, and transmits the polling packet to the CAN bus; the response data receiving unit receives response data frames of the slave nodes from the CAN bus, judges whether the response data frames are received completely according to the frame format, and puts the response data frames into the response data judging unit to judge the frame format and the CCSDS packet format of the effective data field after the response data frames are received completely, and the judging state is sent to the bus fault tolerance management unit; if the judging states received by the bus fault-tolerant management unit are all passed, judging that the response data is valid; otherwise, judging that the response data is invalid, and executing bus reset operation; the bus fault tolerance management unit sends the effective data, the interpretation state and the execution operation to the response state updating unit in the main node data processing module.

8. The solidified satellite-borne CAN bus communication system of claim 7, wherein: the slave node bus communication solidification layer comprises a bus initialization unit, a bus fault tolerance management unit, a polling packet receiving unit, a format interpretation unit, a response buffer unit and an automatic response packet sending unit; the bus initialization unit performs bus communication initialization according to the received parameters, and after the initialization is completed, the receiving polling packet unit receives a data frame from the CAN bus based on the CAN bus communication protocol and sends the data frame to the format interpretation unit; the format interpretation unit interprets the data frame format and the CCSDS packet format of the effective data field, and the interpretation state is sent to the bus fault tolerance management unit; if the judging states received by the bus fault-tolerant management unit are all passed, judging that the polling data is valid; otherwise, judging that the polling data is invalid, and executing bus reset operation; the bus fault tolerance management unit sends effective data, interpretation state and execution operation to the slave node data processing module; the response buffer unit receives response data from the slave node data processing module, and when the response identifier is valid, the automatic response packet sending unit reads the response data framing from the response buffer unit and sends the response data framing to the CAN bus, and the post response identifier is invalid after the transmission is finished.

9. The solidified satellite-borne CAN bus communication system of claim 8, further comprising: the slave node data processing module comprises a configuration parameter unit, a polling state updating unit, a remote control data executing unit and a response data generating unit; the configuration parameter unit sends the station address, the polling data type, the bus code rate and the shielding word of the node to a bus initialization unit in the slave node bus communication solidified layer for bus initialization; the polling state updating unit updates the polling state according to the parameters transmitted from the bus fault tolerance management unit in the node bus communication solidification layer, wherein the polling state updating unit comprises a polling type, a polling interpretation state and polling times; the remote control data execution unit executes related operations according to the content of remote control polling data packets, generates response data packets and sends the response data packets to a response buffer unit in a slave node bus communication solidified layer; if the remote measurement polling is carried out, setting a response mark as effective and sending the response mark to an automatic response sending packet unit in a slave node bus communication solidified layer; and the response data generating unit generates telemetry response data according to the time sequence of the node self-function algorithm, and stores the telemetry response data into a response buffer zone unit in the slave node bus communication solidified layer.

10. The solidified on-board CAN bus communication system of claim 9, further comprising: the slave node shielding words are set to be all recessive and all are logic 1, and the slave nodes filter unnecessary data according to station address filtering and packet master header APID filtering continuous secondary filtering.