Multi-mode self-adaptive switching method for satellite-borne multi-path high-speed data interface

Abstract

The invention discloses a multi-mode self-adaptive switching method for a satellite-borne multi-path high-speed data interface. The method comprises the following steps that: a state machine monitors multi-path data received by a modulator; when any path of data is enabled to arrive, the state machine counts and waits, and judges whether multi-path arrival or single-path arrival is carried out after the specified time is up: if the single-path arrival is carried out, a read-write signal is sent to the modulator; when multiple paths arrive, if the state machine determines that the receiving sequence does not need to be adaptively adjusted, a default sequence receiving signal is sent, and the modulator writes in data according to the default sequence; if the receiving sequence needs to be adjusted in a self-adaptive mode, the state machine judges whether the identifiers are consistent or not, if not, default sequence receiving signals are sent to the modulator, and the modulator writes in according to the default sequence; if yes, the state machine further sends a frame counting sequence receiving signal to the modulator, and the modulator writes in each path of data according to the frame counting sequence; and after the modulator writes in, the data are read out, and the read data are transmitted to the antenna through the radio frequency interface.

Description

Technical Field

[0001] The present invention relates to a multimode adaptive switching method for a spaceborne multi-channel high-speed data interface, belonging to the field of data transmission. Background Art

[0002] Currently, the satellite application industry serving the national economic and social development is showing great vitality. Among them, satellite remote sensing technology can collect a large amount of data in agriculture, forestry, ocean, land, environmental protection, meteorology, etc., and has very broad application scenarios in the fields of land resources, forest resources, geological and mineral resources, water resources, crop yield estimation, disaster prevention and mitigation, etc. While the demand for remote sensing satellites is surging, users hope that their service types are more, the on-orbit robustness is stronger, and the transmission bandwidth is higher, which puts higher requirements on the modulator of the data transmission subsystem of remote sensing satellites. The modulator of the data transmission subsystem receives the remote sensing data transmitted from the front-end payload, and after data processing, encoding, and modulation, it sends the radio frequency signal into the data transmission channel. Therefore, the effective bandwidth part transmitted by the entire data transmission channel is limited by the data interface between the modulator and the front-end payload. To increase the bandwidth of this data interface, it is a feasible method to simultaneously transmit multiple channels of data, process them in parallel, and send them serially. In practical applications, this solution based on the spaceborne multi-channel data interface still has the following problems:

[0003] (1) The multi-channel interface modulator often adopts a single transmission mode. For example, when there are two channels of interfaces between the modulator and the front-end payload, the modulator generally processes data according to the process of two channels of data being transmitted, processed in parallel, and sent serially. When the data transmission of a certain channel is abnormal, or the front-end payload switches to single-channel data transmission, the modulator cannot adapt, which will directly lead to the confusion of valid data and the loss of link lock.

[0004] (2) The multi-channel interface modulator highly depends on command control to switch the transmission mode. In some remote sensing satellites, the modulator will receive the commands transmitted from the front-end controller and passively switch the data interface mode according to the system requirements. On the one hand, this passive switching mode of the data interface needs to add command and response functions to the modulator, increasing the design cost and operation complexity. On the other hand, when a failure occurs in the front-end payload and the command is not transmitted to the modulator in time, it will still lead to the confusion of valid data and the loss of link lock. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: overcoming the deficiencies of the prior art, providing a multimode adaptive switching method for a spaceborne multi-channel high-speed data interface, which can adaptively switch between single-channel and multi-channel data reception modes without an instruction system, and ensure the correct order of valid data when serially transmitted.

[0006] The technical solution of the present invention is: a multimode adaptive switching method for a spaceborne multi-channel high-speed data interface, including:

[0007] After preprocessing by the load data transmission data processor, the data processor transmits the preprocessed data to the modulator through the multi-channel high-speed data interface, and the state machine monitors the data status information received by the modulator; the state machine is an internal algorithm module of the modulator.

[0008] The primary enable signal for each path of data corresponds to the transmission of one frame of data. When the enable signal of any path of data reaches the modulator, the state machine enters the waiting state. When the counter of the state machine counts up to the specified time, it determines whether it is a multi-path arrival or a single-path arrival:

[0009] When it is determined to be a single-path arrival, the state machine sends a read / write signal to the modulator, and the modulator writes the data of this path.

[0010] When it is determined to be a multi-path arrival, the state machine determines whether the multi-path data needs to adaptively adjust the reception order: If it does not need to adaptively adjust the reception order, the state machine sends a default order reception signal to the modulator to make the modulator write the data of each path in the default order; If it needs to adaptively adjust the reception order, the state machine stores the identifiers and frame counter values of each path of data, and first determines whether the identifiers are the same: If the identifiers of each path of data are different, the state machine sends a default order reception signal to the modulator to make the modulator write the data of each path in the default order; If the identifiers are the same, the state machine further sends a frame count order reception signal to the modulator to make the modulator write the data of each path in the frame count order.

[0011] After the modulator completes writing the data in the order given by the state machine, it reads out the data and transmits the read data to the antenna through the radio frequency interface, and ends the process after the transmission is completed.

[0012] Preferably, when the counter of the state machine counts up to the specified time and determines whether it is a multi-path arrival or a single-path arrival:

[0013] The specified time of the counter needs to cover the delay state of the multi-channel high-speed data interface;

[0014] When the counter counts up to the specified time, the state machine determines whether there is an enable arrival of other paths in the waiting state. If there is an enable arrival of other paths of data, it is a multi-path arrival; otherwise, it is a single-path arrival.

[0015] Preferably, when the modulator writes and reads data, each RAM is divided into upper and lower partitions, and the capacity of one partition is greater than the size of one frame of data.

[0016] Preferably, when writing data to a RAM with upper and lower partitions:

[0017] When the first frame of data arrives, it is first written into the upper half of the RAM, and at this time, the read pointer of the RAM remains unchanged; when the first frame of data in the RAM is completely written into the upper half of the RAM, the write pointer of the RAM jumps to the starting position of the lower half, and the read pointer of the RAM jumps to the starting position of the upper half, and the read pointer starts to read the upper half until the first frame of data is completely read out and then stops; when the second frame of data arrives, it is written into the lower half, and after being full, the write pointer jumps back to the starting position of the upper half again, and the read pointer jumps to the starting position of the lower half; when the writing is completed, the read pointer starts to read the lower half until the second frame of data is completely read out and stops; this cycle continues until all data transmissions are completed.

[0018] Preferably, the state machine adjusts the receiving order adaptively according to whether the multiplexed data requires it based on the instructions in the enable signal.

[0019] Preferably, when the modulator receives the data of each path in the default order, specifically: it receives the frame data on the corresponding path in the order of the serial numbers of each interface.

[0020] Preferably, when the modulator receives the data of each path in the frame count order, specifically:

[0021] The state machine further judges the values of the frame counters of the data of each path, and receives the frame data in ascending order of the values of the frame counters to ensure the correct incoming order of the same payload data.

[0022] Preferably, in the case of multiple paths arriving, after the data of each path is written full in half of the RAM, it is read out in the order of the RAM when reading.

[0023] Preferably, the frame data format adopts the data transmission AOS frame format recommended by CCSDS.

[0024] The present invention has the following advantages compared with the prior art:

[0025] (1) The design of the state machine of the present invention provides a data interface design method with higher bandwidth for the data transmission modulator, and expands the data transmission bandwidth of the data transmission channel;

[0026] (2) The adaptive switching feature possessed by the present invention makes the data interface of the modulator more robust and has a wider application scenario. At the same time, the instruction transceiver system can be omitted, saving the design cost. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the data transmission sub-system of the remote sensing satellite of the present invention;

[0028] Figure 2Schematic diagrams of writing and reading under dual-channel data input of the present invention: (a) Schematic diagram of two-channel data arriving and writing to the upper half of the RAM; (b) Schematic diagram of the upper half being fully written; (c) Schematic diagram of reading the upper half and writing the lower half; (d) Schematic diagram of writing and reading simultaneously.

[0029] Figure 3 Flowchart of the control logic of the outer state machine of the present invention;

[0030] Figure 4 Schematic diagram of the data transmission frame format recommended by CCSDS of the present invention. Specific implementation manner

[0031] The present invention provides a multi-mode adaptive switching method based on a spaceborne multi-channel data interface, which can provide a data interface with higher bandwidth, more flexible application, and stronger robustness for the modulator of the data transmission subsystem of a remote sensing satellite, facilitating an increase in the effective data downlink rate of the entire data transmission channel.

[0032] Figure 1 Schematic diagram of the data transmission subsystem of a remote sensing satellite. The modulator is connected after the data processor and before the data transmission microwave channel (antenna). After the front-end payload (camera, SAR, etc.) transmits remote sensing data to the data processor, the data processor will perform pre-data processing on the remote sensing data (such as AOS frame format arrangement); thereafter, the data processor transmits the data to the modulator through a multi-channel high-speed data interface (such as SERDES, 2711, optical port, etc.); after the modulator performs post-data processing on the data (scrambling, encoding, constellation mapping), it is transmitted to the antenna through the RF interface. The bandwidth of the data interface between the data processor and the modulator directly determines the bandwidth of the downlink rate of the entire data transmission channel.

[0033] To avoid possible read-write conflicts when data is transmitted through the multi-channel data interface, for each data interface, the present invention designs a data reading method with upper and lower partitions of the RAM and separate read and write operations. After the modulator is powered on, when the first frame of data arrives, it is first written to the upper half of the RAM, and at this time, the read pointer of the RAM remains unchanged; when the first frame of data is completely written to the upper half of the RAM, the write pointer of the RAM jumps to the starting position of the lower half, and the read pointer of the RAM jumps to the starting position of the upper half; when the "read upper half" instruction is received, the read pointer starts to read the upper half until the first frame of data is completely read out and then stops; when the second frame of data arrives, it is written to the lower half, and after being fully written, it jumps back to the starting position of the upper half; when the "read lower half" instruction is received, the read pointer starts to read the lower half until the second frame of data is completely read out and stops, and so on in a loop. In this write-read mode, reading and writing can be performed simultaneously or non-simultaneously according to the interface situation, and it can be ensured that there will be no problem of conflict between the read pointer and the write pointer. Figure 2 Taking the dual-channel data interface as an example, this data reception method is described.

[0034] When the data interface is extended to multiple channels, each data interface is still used independently Figure 2 The reading method shown, but the writing and reading timing are controlled by the state machine to achieve multi-mode adaptive switching. The state machine is an internal algorithm module of the modulator; the design logic of the state machine is as Figure 3 . Under this method, in the modes where the front-end data processor sends multiple channels of data simultaneously, sends multiple channels of data with offset, or only sends a single channel of data, the modulator can adaptively switch the receiving mode and correctly receive the incoming data. And in the mode where multiple channels of data are incoming simultaneously, the modulator can combine with the AOS frame format, and by judging the type identifier and the frame counter, automatically switch the writing order to ensure the correct order of the read data. Among them, the recommended AOS frame format for data transmission by CCSDS is as Figure 4 .

[0035] Figure 1 is a schematic diagram of the data transmission sub-system of a remote sensing satellite. The modulator is located after the data processor and before the data transmission microwave channel. After the data processor pre-processes the remote sensing data of the main payload, it is transmitted into the modulator through the data interface; the modulator post-processes the data and transmits it into the data transmission microwave channel through the RF port. Therefore, the effective rate of the data interface between the modulator and the data processor is one of the bottlenecks of the effective bandwidth of the entire data transmission channel for ground transmission. The present invention can provide a data processing method with higher bandwidth, stronger robustness, and broader application scenarios for the data interface between the modulator and the data processor, indirectly expanding the effective bandwidth of the entire data transmission channel.

[0036] The designed data receiving method of the present invention has the same writing and reading methods for each data interface, and they are independent of each other. Figure 2 shows this writing and reading method: each data interface has a RAM with upper and lower partitions; when the first frame of data arrives, the modulator first passes the data through the input buffer, and after clock synchronization processing, writes it into the upper half of the RAM; when the write pointer of the RAM writes to the upper half, the read pointer does not move; until the upper half is full and the first frame of data is written, the read pointer starts to read data from the upper half, and at the same time the write pointer jumps to the starting position of the lower half, waiting for the second frame of data to arrive. Under this writing and reading method, the data is alternately written into the upper and lower halves of the RAM, and it is ensured that after a certain half is full, the data in that half is read, and at the same time it does not affect the writing of the subsequent valid data into the other half. In this mode, the read and write pointers do not interfere with each other, and the content and order of the read data will not be incorrect.

[0037] In addition, the writing and reading timing of each channel of data are controlled by the outer state machine, and the design logic of the state machine is as Figure 3After the modulator is ready, the state machine is ready and waits for the data enable signal of any path to arrive. One data enable signal for each path corresponds to the transmission of one frame of data. When the data enable signal of any path arrives, the state machine enters the waiting state because the time delays of the data processor and each data interface of the modulator are different, which may cause the data enable signals received by the modulator not to arrive simultaneously in the multi-path simultaneous transmission mode of the data processor. Designers can design the waiting time according to the time delay state of the link distance. When the counter counts up to the specified time, the state machine determines whether there are data enables of other paths arriving in the waiting state. If there are data enables of other paths arriving, it enters the multi-path reception mode; otherwise, it enters the single-path reception mode.

[0038] In the multi-path reception mode, the state machine first determines whether the designer requires adaptive adjustment of the reception order. If adaptive adjustment of the order is not required, after each path of data fills half of the RAM area, the state machine reads in the default order. In the mode of adaptive adjustment of the reception order, the state machine reads the data type identifier and frame counter in the AOS frame format of multi-path data, and determines the order of writing data to each path of RAM according to the principle that under the same type identifier, the frame counter with a smaller value comes first and the one with a larger value comes later. After that, wait until each path of data fills half of the RAM, and then read in the order of the RAM. In the single-path reception mode, the program determines the data interface number of the arriving data, waits until the data fills half of the RAM area, and then the modulator starts to read the data.

[0039] When the modulator has multiple data interfaces, such as four interfaces A, B, C, and D. The data on the interfaces may arrive simultaneously or non-simultaneously. The modulator can correctly receive the data arriving on a single path or simultaneously on multiple paths on these interfaces. In the state of simultaneous arrival of multiple paths, the modulator can receive the four paths of data completely and store them in the RAM according to the interface number (i.e., the default state).

[0040] When the modulator needs to receive data in the order of frame count, it receives the data of each path in the order of frame count. For example, if the modulator has four interfaces A, B, C, and D, the data transmitted on each interface may be the same type of payload data (the frame identifier is the same), or different types of payload data (the frame identifier is different). When multiple paths of data are simultaneously input on the interfaces, the modulator can first obtain the frame identifiers of each path of data before the RAM write operation and determine whether they are the same type of payload data. If it is the same type of payload data, it receives the data in the order of frame count (this can ensure that the order of the same type of payload data will not be disordered after being transmitted to the ground); if it is not the same type of payload, it still stores the data in the order of the interface number in the RAM.

[0041] The content not described in detail in the specification of the present invention belongs to the prior art well-known to those skilled in the art.

Claims

1. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface, characterized in that Including: After the payload data is transmitted to the data processor for preprocessing, the data processor transmits the preprocessed data to the modulator through a multi-channel high-speed data interface, and the state machine monitors the data status information received by the modulator; the state machine is an internal algorithm module of the modulator. The primary enable signal for each path of data corresponds to the transmission of one frame of data. When the enable signal of any path of data reaches the modulator, the state machine enters the waiting state. When the counter of the state machine counts up to the specified time, it is determined whether it is a multi-path arrival or a single-path arrival: When it is determined to be a single-path arrival, the state machine sends a read / write signal to the modulator, and the modulator writes the data of this path. When it is determined to be a multi-path arrival, the state machine determines whether the multi-path data needs to adaptively adjust the reception order: If the reception order does not need to be adaptively adjusted, the state machine sends a default-order reception signal to the modulator to make the modulator write the data of each path in the default order; If the reception order needs to be adaptively adjusted, the state machine stores the identifiers and frame counter values of each path of data. First, it determines whether the identifiers are the same: If the identifiers of each path of data are different, the state machine sends a default-order reception signal to the modulator to make the modulator write the data of each path in the default order; If the identifiers are the same, the state machine further sends a frame-count-order reception signal to the modulator to make the modulator write the data of each path in the frame-count order; After the modulator completes the data writing according to the order given by the state machine, it reads out the data and transmits the read data to the antenna through the radio frequency interface, and the process ends after the transmission is completed.

2. The multi-mode adaptive switching method of a spaceborne multi-channel high-speed data interface according to claim 1, characterized in that: When the counter of the state machine counts up to the specified time and determines whether it is a multi-path arrival or a single-path arrival: The specified time of the counter needs to cover the delay state of the multi-channel high-speed data interface; When the counter counts up to the specified time, the state machine determines whether there is an enable signal of other paths arriving during the waiting state. If there is an enable signal of other paths of data arriving, it is a multi-path arrival; Otherwise, it is a single-path arrival.

3. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface according to claim 1, characterized in that: When the modulator performs data writing and reading, each RAM has upper and lower partitions, and the capacity of one partition is greater than the size of one frame of data.

4. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface according to claim 3, characterized in that: When writing data to a RAM with upper and lower partitions: When the first frame of data arrives, it is first written into the upper half of the RAM, and the read pointer of the RAM does not move at this time; when the first frame of data is completely written into the upper half of the RAM, the write pointer of the RAM jumps to the starting position of the lower half, and the read pointer of the RAM jumps to the starting position of the upper half, and the read pointer starts to read the upper half until the first frame of data is completely read out and then stops; After the second frame of data arrives, it is written into the lower half. After being written full, the write pointer jumps back to the starting position of the upper half again, and the read pointer jumps to the starting position of the lower half; when the writing is completed, the read pointer starts to read the lower half until the second frame of data is completely read out and stops; and so on in a cycle until all data transmissions are completed.

5. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface according to claim 1, characterized in that: The state machine determines whether the multi-path data needs to adaptively adjust the reception order according to the instruction in the enable signal.

6. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface according to claim 1, characterized in that: When the modulator receives the data of each path in the default order, specifically: it receives the frame data on the corresponding path in the order of the serial numbers of each path interface.

7. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface according to claim 1, characterized in that: When the modulator receives the data of each path in the frame-count order, specifically: The state machine further judges the frame counter values of each path of data, receives the frame data in ascending order of the frame counter values, and ensures the correct incoming order of the same kind of payload data.

8. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface according to claim 1, characterized in that: In the case of multiple paths arriving, after each path of data fills half of the RAM, the data is read out in the order of the RAM when reading.

9. A multi-mode adaptive switching method for a spaceborne multi-channel high-speed data interface according to claim 7, characterized in that: The frame data format adopts the data transmission AOS frame format recommended by CCSDS.

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