Differential navigation data framing transmission method

Abstract

The invention provides a differential navigation data framing transmission method which is characterized by comprising the following steps: S1, a frame synchronization module receives an input signal and judges whether a data frame header is a required data frame header; s2, taking a first byte behind a frame header of the data frame, and judging whether the data frame is valid or not; and S3, when the data frame is an effective frame and a plurality of data exist in the first-in first-out FIFO cache, reading is started, and reading is stopped until no data exist in the first-in first-out cache, so that transmission of the navigation data frame is completed. According to the differential navigation data framing transmission method, based on hardware design, link protocol design and reliability and safety design of FPGA firmware data framing, the validity of data transmission is confirmed by using a frame type flag bit in data, and once communication is established with navigation equipment, the whole link is kept in a communication state all the time.

Description

Technical Field

[0001] The present invention relates to the field of data framing transmission, and in particular to a differential navigation data framing transmission method. Background Art

[0002] The frame of navigation data includes not only the frame header, frame footer, valid data, and checksum, but also the frame type. The frame type is the index number of a data frame, indicating the type of data frame currently being sent or received. The valid data in the navigation data includes the latitude and longitude of the current device location, the number of receivable navigation satellites, etc. The device environment status parameters directly reflect the location status of the device and provide a basis for the navigation and positioning of the back-end device.

[0003] Patent document CN116909978B discloses a data framing method, device, electronic device and storage medium, but the data to be framed needs to be cached in a first cache unit and a second cache unit in sequence, and then framed after a handshake protocol and the required data size, which takes a long time for data transmission.

[0004] Patent document CN114706100B discloses a differential data broadcasting method based on Beidou RDSS, which generates RDSS differential data after receiving the differential data sent down, and then frames and broadcasts the compressed RDSS differential data, but cannot achieve the continuity of navigation link communication. Summary of the invention

[0005] To solve the above problems, the present invention provides a differential navigation data framing transmission method based on FPGA firmware data framing. After the navigation device establishes communication with a framing machine, the framing machine maintains the entire link in a communication state.

[0006] The present invention provides a differential navigation data framing transmission method, characterized in that it comprises the following steps:

[0007] S1, the frame synchronization module receives the input signal and determines whether the data frame header is the required data frame header;

[0008] S2, take the first byte after the data frame header, and determine whether the data frame is valid;

[0009] S3. When the data frame is a valid frame and there is data in the FIFO buffer, it starts to read out, and stops reading when there is no data in the FIFO buffer, thus completing the transmission of the navigation data frame.

[0010] Furthermore, if the data frame header in step S1 is the required data frame header, the frame synchronization flag signal is pulled high; if the data frame header in step S1 is not the required data frame header, the search for the required data frame header is returned.

[0011] Furthermore, the first byte after the data frame header in step S2 is a valid frame flag:

[0012] When the entire data frame is valid, the valid data starts to be written into the FIFO buffer and the write count starts until the write count reaches the valid frame length and the writing stops.

[0013] When part of the data frame is valid, the valid data is written into the FIFO buffer and the write count is started until the write count reaches the valid frame length, then the writing count is stopped and the invalid data is filled after the valid count to a full frame.

[0014] Furthermore, in step S2, the first byte after the data frame header is an invalid frame flag, and invalid data is filled to a whole frame, and an invalid frame is sent.

[0015] Furthermore, the differential navigation data frame is 200 bytes, including a data frame header bit, a valid / invalid frame flag bit, a valid byte number bit, a frame count bit, and a data byte bit.

[0016] Furthermore, the data frame header is represented by EB90, which is 2 bytes.

[0017] Furthermore, the valid / invalid frame flag is the first byte after the data frame header, the valid frame bit is represented by AA, and the invalid frame bit is represented by 66.

[0018] Furthermore, the valid byte number is the number of valid bytes in the data byte position of the data frame, representing valid frame length information.

[0019] Furthermore, the frame count bit represents which frame of data the data frame is.

[0020] Furthermore, the data byte is a demodulated data byte.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The differential navigation data framing transmission method of the present invention is based on the hardware design, link protocol design, reliability and security design of FPGA firmware data framing, and uses the frame type flag in the data to confirm the validity of data transmission, so as to maintain the communication state of the entire link once communication is established with the navigation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions disclosed in the present invention, the following briefly introduces the drawings required to be used in some embodiments disclosed in the present invention. Obviously, the drawings described below are only drawings of some embodiments disclosed in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the products involved in the embodiments disclosed in the present invention, the actual process of the method, etc.

[0024] Figure 1 The invention discloses a differential navigation data framing transmission method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0026] like Figure 1 The figure shows a differential navigation data framing transmission method provided by an embodiment of the present invention. Based on FPGA firmware data framing, after the navigation device establishes communication with the framing stand-alone machine, the framing stand-alone machine maintains the entire link in a communication state. The method includes the following steps:

[0027] S1, the frame synchronization module receives an input signal, determines whether the data frame header is the required data frame header, and if the data frame header is the required data frame header, pulls the frame synchronization flag signal high;

[0028] If the data frame header is not the required data frame header, the process returns to search for the required data frame header.

[0029] S2. Get the first byte after the data frame header to determine whether the data frame is valid

[0030] The first byte after the data frame header is a valid frame flag:

[0031] When the entire data frame is valid, the valid data starts to be written into the first-in-first-out (FIFO) buffer and the write count starts until the write count reaches the valid frame length and the writing stops.

[0032] When part of the data frame is valid, the valid data is written into the FIFO buffer and the write count is started until the write count reaches the valid frame length, at which time the write count is stopped and invalid data is filled after the valid count to a full frame.

[0033] The first byte after the data frame header is an invalid frame flag:

[0034] Fill invalid data to a whole frame and send an invalid frame;

[0035] S3. When the data frame is a valid frame and there is data in the FIFO buffer, it starts to read out, and stops reading when there is no data in the FIFO buffer, thus completing the transmission of the navigation data frame.

[0036] In one embodiment, the differential navigation data frame is 200 bytes, including a data frame header, a valid / invalid frame flag, a valid byte digit, a frame count, and a data byte digit. The data frame header is represented by EB90, which is 2 bytes; the valid / invalid frame flag is the first byte after the data frame header, the valid frame is represented by AA, and the invalid frame is represented by 66; the valid byte digit is the number of valid bytes in the data frame data byte digit, representing the valid frame length information; the frame count indicates which frame of data the data frame is; and the data byte digit is the demodulated data byte.

[0037] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention using the above disclosed contents without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the contents of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A differential navigation data framing transmission method, characterized in that: The following steps are involved: S1, the frame synchronization module receives the input signal and determines whether the data frame header is the required data frame header; S2, take the first byte after the data frame header, and determine whether the data frame is valid; S3. When the data frame is a valid frame and there is data in the FIFO buffer, it starts to read out, and stops reading when there is no data in the FIFO buffer, thus completing the transmission of the navigation data frame.

2. A differential navigation data framing transmission method according to claim 1, characterized in that: If the data frame header in step S1 is the required data frame header, the frame synchronization flag signal is pulled high; if the data frame header in step S1 is not the required data frame header, the process returns to find the required data frame header.

3. The differential navigation data framing transmission method according to claim 1, characterized in that: The first byte after the data frame header in step S2 is a valid frame flag: When the entire data frame is valid, the valid data starts to be written into the FIFO buffer and the write count starts until the write count reaches the valid frame length and the writing stops. When part of the data frame is valid, the valid data is written into the FIFO buffer and the write count is started until the write count reaches the valid frame length, then the writing count is stopped and the invalid data is filled after the valid count to a full frame.

4. The differential navigation data framing transmission method according to claim 1, characterized in that: In step S2, the first byte after the data frame header is an invalid frame flag, and invalid data is filled to a full frame, and an invalid frame is sent.

5. The differential navigation data framing transmission method according to claim 1, characterized in that: The differential navigation data frame is 200 bytes, including a data frame header bit, a valid / invalid frame flag bit, a valid byte number bit, a frame count bit, and a data byte bit.

6. A differential navigation data framing transmission method according to claim 5, characterized in that: The data frame header is represented by EB90, which is 2 bytes.

7. A differential navigation data framing transmission method according to claim 5, characterized in that: The valid / invalid frame flag is the first byte after the data frame header, the valid frame bit is represented by AA, and the invalid frame bit is represented by 66.

8. The differential navigation data framing transmission method according to claim 5, characterized in that: The valid byte number is the number of valid bytes in the data byte position of the data frame, representing the valid frame length information.

9. The differential navigation data framing transmission method according to claim 5, characterized in that: The frame count bit represents the data frame number of the data frame.

10. The differential navigation data framing transmission method according to claim 5, characterized in that: The data byte bits are demodulated data bytes.

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