阅读说明：本技术 一种基于北斗短报文的望远镜远程数据传输与控制方法 (Telescope remote data transmission and control method based on Beidou short message ) 是由 谭思远 姚骑均 段文英 林镇辉 于 2020-11-17 设计创作，主要内容包括：本发明公开了一种基于北斗短报文的望远镜远程数据传输与控制方法,它通过设计协议,设置DT标志位,对具体数据中存在的特殊字符进行转义,对较大数据块采取分帧组帧机制,对实际传输的数据进行必要的差错控制和拥塞控制机制,成功地实现了利用北斗短报文RDSS-DTU传输望远镜远程数据的功能。应用本发明的数据传输方法,使用户能够传输包含特定字符的短报文,且传回的观测数据持续正常,保证了通信的可靠性。(The invention discloses a telescope remote data transmission and control method based on Beidou short messages, which sets DT flag bits through designing a protocol, performs escape on special characters existing in specific data, adopts a framing and framing mechanism for a larger data block, performs necessary error control and congestion control mechanisms on actually transmitted data, and successfully realizes the function of transmitting telescope remote data by using the Beidou short messages RDSS-DTU. By applying the data transmission method of the invention, the user can transmit the short message containing the specific character, and the returned observation data is continuous and normal, thereby ensuring the reliability of communication.)

1. A telescope remote data transmission and control method based on Beidou short messages is characterized by comprising the following steps:

s1, dividing the data segment from the highest bit to the lowest bit into 4 protocol fields: SCF (2 bits), DT (6 bits), SN (8 bits), DataLoad (600 bits);

s2, defining a protocol field SCF (2 bits) for indicating whether the data is framed; if the data to be transmitted is larger than the maximum 76 bytes supported by each frame, splitting the transmitted data into a plurality of frames for transmission;

s3, defining a protocol field DT (6 bits) for indicating a user data type;

s4, defining a protocol field SN (8 bits) for representing a frame number, and distinguishing single-frame data and multi-frame data by using the protocol field SN corresponding to the SCF;

s5, defining a processing method for multi-frame data receiving and transmitting integrity: when multi-frame data starts to be sent, the total data frame number is given through the SN; if the received SNs are continuous and the last frame is received, all the frame data are received; if the SN is missing, sending a general response frame to request the receiving end to send the specific data segment again;

s6, defining a processing method for data including special characters:

a sending end: the escape character is represented by 0x7D, and the user Data is filtered from the first byte of the Data Frame; escape 0x7D in user data to 0x7D, 0x 5D; then, searching all the user data after escaping, and escaping 0x0D if finding that continuous 0x0D-0x0A appears;

receiving end: for the last frame of a single frame or continuous data frames, obtaining the length of the data load and judging the end of the data by using two fields of SCF and SN according to the rule in the step S4;

s7, storing original data to be sent into a data buffer area in a memory, and performing escape processing on specific byte sequences continuously appearing in the original data according to the data preprocessing method of the sending end in the step S6;

s8, calculating the concrete numerical values of each field according to the frame structure and the fields defined in the steps S2 to S4 for the preprocessed data, and combining the numerical values to obtain a data frame;

s9, grouping the generated data frames according to types and adding the data frames into a data sending queue in sequence;

s10, for the receiving end, reading the data state of the receiving buffer area every 1S; extracting all the framed data, and combining the frame data to generate a complete data frame;

s11, carrying out preprocessing reduction on the complete data frame generated in the step S10 according to the receiving end processing method in the step S6 to obtain original data.

2. The telescope remote data transmission and control method as claimed in claim 1, wherein in step S3, 64 types of data are reserved for the frame format; the user data types include, general response frame (0x00), weather station data (0x01), system script execution data (0x02), device monitoring status data (0x 03).

3. The telescope remote data transmission and control method according to claim 1, wherein step S4 includes defining SCF-0 x00 as consecutive frames, SN indicating the current data frame number in the multi-frame data; SCF 0x01 represents the first frame of multi-frame data, and SN is the total number of frames of transmission data; SCF-0 x10 indicates the last frame of multi-frame data, and SN indicates the data length of the current data frame; SCF-0 x11 indicates a single data frame, and SN indicates the data length of the current data frame.

4. The telescope remote data transmission and control method according to claim 2, wherein the step S5 further comprises buffering all current consecutive data frames by both the transmitting end and the receiving end during data reception and transmission until receiving the response frame from the other end, and removing the buffering after confirming that all data frames have been received.

5. The telescope remote data transmission and control method according to claim 4, wherein the response frame type is data of 0x00 type defined in step S3, the first byte in the content represents the total number N of received data frames, and starting from the second byte, the status of each bit represents whether the corresponding data frame is received.

6. The telescope remote Data transmission and control method as claimed in claim 1, wherein the transmitting end in step S6 includes, for consecutive frames, the bytes of the current Data Frame that exceed the Data load length after being processed are included in the Data Frame of the next Frame.

7. The telescope remote data transmission and control method as claimed in claim 1, wherein the receiving end in step S6 includes, for consecutive data frames, directly intercepting as 77 bytes DataFrame; when all Data is received, all 0x7D are scanned from the first byte of Data Load, if 0x7D occurs, 0x7D is removed and 1 byte after 0x7D is exclusive-ored to 0x 20.

8. The telescope remote data transmission and control method as claimed in claim 1, wherein the step S8 includes performing data splitting on the preprocessed data with length greater than 75 bytes, and generating frame data of all the sub-frames as defined in the steps S2 and S4.

9. The telescope remote data transmission and control method as claimed in claim 1, wherein the step S9 includes that the basic unit of the data transmission queue is a data frame of a data type, and each element in the queue transmits each frame data sequentially at a specific time interval in a first-come-first-served order by default.

10. The telescope remote data transmission and control method as claimed in claim 1, wherein the step S10 comprises obtaining the values of the relevant fields and the preprocessed data according to the data frame structure after the data is received in the receiving buffer; obtaining the data type according to the DT field in the step S3, and judging whether the data frame is framed according to the definition of the SN field in the step S4; if the frame is a single frame, acquiring the byte length of the data segment through the SN; if the data is multi-frame data and not a tail frame, extracting the data according to the length of 75 bytes; when the last frame is received, acquiring the data length of the current frame according to the SN field; and when all the framed data are extracted, combining the frame data and generating a complete data frame.

Technical Field

The invention belongs to the technical field of observation data transmission and control, and particularly relates to a telescope remote data transmission and control method based on Beidou short messages.

Background

At present, some scientific research projects need to set up an unattended small-sized observation station to collect weather and other data around a candidate astronomical site in an unmanned area, and need to realize that observation data on site of the site can be transmitted back to the astronomical site, and the site can remotely control observation tasks on site. As the unmanned area of the abdominal region of the Qinghai-Tibet plateau does not have conventional communication modes such as mobile communication, optical fiber communication and the like at present, the environmental parameters of the candidate astronomical site are sequentially evaluated, and the process needs to uninterruptedly acquire environmental observation data near the candidate site and return the data in real time and evaluate the data in time. Therefore, a feasible method of returning field observation data can only be via satellite communication. In view of that the Beidou satellite navigation system independently constructed in China can provide RDSS-DTU short message service, the sending time interval of the Beidou No. 2 short message for common users is 60s, the maximum data which can be supported by each message is not more than 80 bytes (different commercial short message platforms have slight difference), and the price is also greatly lower than the communication charge of maritime satellites and iridium satellites. The method can meet the tasks of returning and remotely controlling the observation data in the early period in an inexpensive manner. With formal operation of the Beidou No. 3 global satellite navigation system, the short message communication capacity is also upgraded. Compared with Beidou No. 2, the data of each message of providing RDSS-DTU short message service of Beidou No. 3 in the regional range is expanded to 1750 bytes, so that the method can adapt to the growth change of future astronomical site observation data, and also provides technical accumulation for other telescope remote data transmission adopting narrow-band communication.

The application of the Beidou short message RDSS-DTU as a communication mode generally utilizes a commercial Beidou short message platform, the platform provides a Beidou communication card, a radio frequency circuit and an antenna, for a common user, the operation of sending the short message by Beidou short message communication equipment is to send data in a fixed format to a port of the equipment, and the operation of receiving the short message is to read the data in the fixed format from the port of the equipment. However, such fixed format data cannot contain a specific character sequence, which requires the user to preprocess the data. In addition, for a specific device platform, the data length has a certain byte limit, which means that the operations of data framing, framing and the like must be processed by a user corresponding to larger data. In addition, the platform does not provide necessary error control and congestion control mechanisms after data is sent out, and users need to add the mechanisms by themselves in order to ensure the reliability of communication.

Disclosure of Invention

The invention researches and designs a set of efficient and universal data transmission and control method based on the Beidou short message RDSS-DTU, which is used for performing escape on special characters in specific data, adopting a framing and framing mechanism for a larger data block, performing necessary error control and congestion control mechanism on actually transmitted data, and finally realizing that the designed scheme can be applied to other applications of communication in any adopted Beidou short message mode.

Aiming at the defects in the prior art, the invention provides a telescope remote data transmission and control method based on Beidou short messages, which comprises two parts: 1) a set of universal data transmission protocol is designed; 2) a data transmission processing flow and a control method are designed.

The designed general data transmission protocol is defined on a user-defined data part provided by a Beidou satellite short message platform, and the invention adopts the following technical scheme: a telescope remote data transmission and control method based on Beidou short messages comprises the following steps:

s1, dividing the data segment from the highest bit to the lowest bit into 4 protocol fields: SCF (2 bits), DT (6 bits), SN (8 bits), DataLoad (600 bits);

s2, defining a protocol field SCF (2 bits) for indicating whether the data is framed; if the data to be transmitted is larger than the maximum 76 bytes supported by each frame, splitting the transmitted data into a plurality of frames for transmission;

s3, defining a protocol field DT (6 bits) for indicating a user data type;

s4, defining a protocol field SN (8 bits) for representing a frame number, and distinguishing single-frame data and multi-frame data by using the protocol field SN corresponding to the SCF;

s5, defining a processing method for multi-frame data receiving and transmitting integrity: when multi-frame data starts to be sent, the total data frame number is given through the SN; if the received SNs are continuous and the last frame is received, all the frame data are received; if the SN is missing, sending a general response frame to request the receiving end to send the specific data segment again;

s6, defining a processing method for data including special characters:

a sending end: the escape character is represented by 0x7D, and the user Data is filtered from the first byte of the Data Frame; escape 0x7D in user data to 0x7D, 0x 5D; then, searching all the user data after escaping, and escaping 0x0D if finding that continuous 0x0D-0x0A appears;

receiving end: for the last frame of a single frame or continuous data frames, obtaining the length of the data load and judging the end of the data by using two fields of SCF and SN according to the rule in the step S4;

s7, storing original data to be sent into a data buffer area in a memory, and performing escape processing on specific byte sequences continuously appearing in the original data according to the data preprocessing method of the sending end in the step S6;

s8, calculating the concrete numerical values of each field according to the frame structure and the fields defined in the steps S2 to S4 for the preprocessed data, and combining the numerical values to obtain a data frame;

s9, grouping the generated data frames according to types and adding the data frames into a data sending queue in sequence;

s10, for the receiving end, reading the data state of the receiving buffer area every 1S; extracting all the framed data, and combining the frame data to generate a complete data frame;

s11, carrying out preprocessing reduction on the complete data frame generated in the step S10 according to the receiving end processing method in the step S6 to obtain original data.

In order to optimize the technical scheme, the specific measures adopted further comprise:

further, in step S3, 64 types of data are reserved in the frame format; the user data types include, general response frame (0x00), weather station data (0x01), system script execution data (0x02), device monitoring status data (0x 03).

Further, step S4 includes defining that SCF-0 x00 represents consecutive frames, and SN indicates the current data frame number in the multi-frame data; SCF 0x01 represents the first frame of multi-frame data, and SN is the total number of frames of transmission data; SCF-0 x10 indicates the last frame of multi-frame data, and SN indicates the data length of the current data frame; SCF-0 x11 indicates a single data frame, and SN indicates the data length of the current data frame.

Further, step S5 includes that, when receiving and transmitting data, both the transmitting end and the receiving end need to buffer all current continuous data frames until receiving the response frame of the other end, and it is determined that all data frames are received, and then the buffer cannot be cleared.

Further, the response frame type is data of type 0x00 defined in step S3, the first byte in its content represents the total number N of received data frames, and starting from the second byte, the state of each bit represents whether the corresponding data frame is received or not.

Further, in step S6, the sender includes, for consecutive frames, the bytes of the current Data Frame that exceed the Data load length after being processed are included in the Data Frame of the next Frame.

Further, the receiving end in step S6 includes, for the consecutive data frames, directly intercepting the data frames according to 77 bytes; when all Data is received, all 0x7D are scanned from the first byte of Data Load, if 0x7D occurs, 0x7D is removed and 1 byte after 0x7D is exclusive-ored to 0x 20.

Further, step S8 includes performing data splitting on the preprocessed data with length greater than 75 bytes, and generating frame data of all the subframes according to the definitions in step S2 and step S4.

Further, step S9 includes that the basic unit of the data transmission queue is a data frame of data type, and each element in the queue transmits each frame data in turn at a specific time interval in a first-come-first-transmit order by default.

Further, step S10 specifically includes, after the receiving buffer has received the data, obtaining the value of the relevant field and the preprocessed data according to the data frame structure; obtaining the data type according to the DT field in the step S3, and judging whether the data frame is framed according to the definition of the SN field in the step S4; if the frame is a single frame, acquiring the byte length of the data segment through the SN; if the data is multi-frame data and not a tail frame, extracting the data according to the length of 75 bytes; when the last frame is received, acquiring the data length of the current frame according to the SN field; and when all the framed data are extracted, combining the frame data and generating a complete data frame.

The invention has the beneficial effects that: the invention sets DT zone bits through designing a protocol, performs escape on special characters existing in specific data, adopts a framing and framing mechanism for a larger data block, performs necessary error control and congestion control mechanisms on actually transmitted data, and successfully realizes the function of transmitting telescope remote data by using the Beidou short message RDSS-DTU. By applying the data transmission method of the invention, the user can transmit the short message containing the specific character, and the returned observation data is continuous and normal, thereby ensuring the reliability of communication. The method provided by the invention can also be applied to other applications of communication in any short message mode, and has important significance for actively promoting the development of the Beidou satellite industry.

Drawings

Fig. 1 is a flow chart of the telescope remote data transmission method based on the big dipper short message.

Fig. 2 is a field schematic diagram of a data transmission protocol commonly used for telescope remote data transmission based on the Beidou short message.

Fig. 3 shows a screenshot of a sending and receiving data stream (under an ubuntu linux operating system) obtained by performing a certain actual data transmission by using the method of the present invention.

Detailed Description

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

In an embodiment of the invention, Beidou short message communication equipment which is independently developed and produced by Shanghai Beijing industrial automation company Limited is adopted by a Beidou short message platform aiming at a cold lake area station address, and can support single-time data message transmission of maximum data of 77 bytes. Because the platform provides the Beidou communication card, the radio frequency circuit and the antenna, for a common user, the operation of sending the short message is to send data with a fixed format to the port of the equipment, and the operation of receiving the short message is to read the data with the fixed format from the port of the equipment. However, such fixed format data cannot contain a specific character sequence, which requires the user to preprocess the data. In addition, the data length is limited to 77 bytes, which means that the user has to deal with data framing, etc. for larger data. In addition, the platform does not provide necessary error control and congestion control mechanisms after data is sent out, and users can add the mechanisms to ensure the reliability of communication.

In order to realize the communication task of astronomical site remote observation data transmission and control based on the Beidou short message platform, three major problems need to be solved. Therefore, a set of general data transmission protocol needs to be established on the existing Beidou short message RDSS-DTU data structure. The universal transmission protocol and the universal transmission method can be applied to the site observation data transmission task in the early engineering of the cold lake, can also be applied to other applications of communication in any short message mode, and have positive significance for promoting the development of the Beidou satellite industry in China. In addition, the method is easy to expand, and is convenient to be transplanted to a short message data structure of a Beidou No. 3 satellite subsequently and conveniently, so that more transmission data capacity is borne.

In view of this, a set of efficient and general data transmission and control method based on the beidou short message RDSS-DTU needs to be researched and designed, the special characters existing in specific data are transferred, a framing and framing mechanism is adopted for a large data block, necessary error control and congestion control mechanisms are carried out on actually transmitted data, and finally the designed scheme can be applied to other applications of communication in any adopted beidou short message mode. In addition, aiming at various types of data and control instructions involved in telescope remote operation and control, an effective method for processing and responding to the various types of data and control instructions needs to be researched, and a solution is provided for promoting the application of the Beidou satellite industry, particularly Beidou satellite navigation, in a telescope remote operation and control system.

The invention provides a universal method for telescope remote data transmission and control by using Beidou short messages, which comprises two parts: 1) a set of universal data transmission protocol is designed; 2) a data transmission processing flow and a control method are designed.

Wherein, the general data transmission protocol who designs is defined on the user's self-defined data part that big dipper satellite short message platform provided, and user's self-defined data length is 77 bytes in the big dipper satellite short message platform that this embodiment adopted, and to these 77 bytes, as shown in fig. 2, the data transmission protocol who designs includes:

s1, dividing the data segment of 77 bytes (616 bits) into 4 parts (the middle parenthesis indicates the bit length) from the highest bit to the lowest bit: SCF [2 bit ], DT [6 bit ], SN [8 bit ], DataLoad [600 bit ];

s2, the protocol field SCF [2 bits ] is used to indicate whether the data is framed or not. If the data to be transmitted is larger than the maximum 76 bytes supported by each frame, the transmitted data must be split into a plurality of frames for transmission, the SCF has 4 different values, and the significances represented by the values are explained in S4;

s3, protocol field DT [6 bits ] is used to indicate the user data type. The designed frame format reserves 64 types of data. To ensure compatibility with data transfer between the simple command mode PC and DTU, DT cannot occur in two types, 0x22 and 0x0D, so that a total of 62 different data types can be supported, which are currently determined to be: general response frames (0x00), weather station data (0x01), system script execution data (0x02), device monitoring status data (0x03), other types may follow-up. The user can design and customize the Data structure type in the Data load section in conjunction with the DT.

S4, and the protocol field SN (8 bits) is used for indicating the frame number and is used together with the SCF to realize the discrimination of single-frame or multi-frame data. The design rule is as follows: SCF-0 x00 indicates consecutive frames, and SN indicates the current data frame number in the multi-frame data. SCF 0x01 indicates the first frame of multi-frame data, and SN is the total number of frames of transmission data. SCF 0x10 indicates the last frame of multi-frame data, and SN indicates the data length of the current data frame. SCF-0 x11 indicates a single data frame, and SN indicates the data length of the current data frame.

S5, the processing method of the protocol to the integrity of multi-frame data receiving and transmitting is as follows: when multi-frame data starts to be transmitted, the total data frame number is given through SN. If the received SNs are continuous and the last frame is received, all the frame data are received; if the SN is missing, the receiving end can be requested to send a specific data segment again by sending a general response frame through the control protocol. When receiving and transmitting data, both the transmitting end and the receiving end need to buffer all current continuous data frames, and the buffering can not be cleared until the response frame of the other side is received to confirm that all the data frames are received. The response frame type is data of type 0x00 defined in S3, the first byte in the content represents the total number N of received data frames, and starting from the second byte, the state of each bit represents whether the corresponding data frame is received (0: indicating not received; 1: indicating received), and represents the first frame and the second frame … … in sequence from left to right.

S6, a processing method of the protocol for the data containing the special characters:

a sending end: referring to the HDLC filtering protocol, escape characters are denoted by 0x 7D. Starting from the first byte of the Data Frame, the user Data (up to 75 bytes at a time) is filtered. Escape 0x7D in user data to 0x7D, 0x 5D. Then, all the user data after the escape is searched, and if the continuous 0x0D-0x0A is found, we escape 0x0D (add 0x7D before 0x0D, and xor 0x20H to the following 0x0D to become 0x 2D). For the continuous frames, the bytes of the current Data Frame which exceed the Data load length after the processing are included in the Data Frame of the next Frame.

Receiving end: for the last frame of a single frame or consecutive data frames, the length of the data load is obtained and the end of data is judged by means of the SCF and SN fields and referring to the rule in S4. For consecutive data frames, they belong to fixed-length data because they fill the entire RDSS maximum data capacity. We only need to directly intercept 77 bytes DataFrame. For insurance, the \ r \ n end flag is also checked after 77 bytes. When all Data is received, all 0x7D are scanned from the first byte of Data Load, if 0x7D occurs, 0x7D is removed and the next 1 byte is exclusive-ored to 0x 20. For example, 0x7D-0x2D-0x0A contained in the Data Frame becomes 0x0D-0x0A after the above rule processing.

The data transmission processing flow and control method of the present invention is shown in fig. 1, and comprises:

s7, storing original data to be transmitted into a data buffer area in a memory, and performing escape processing on specific byte sequences (0x7D and 0x0D-0x0A) continuously appearing in the original data according to a data preprocessing method of a transmitting end in S6;

and S8, calculating specific values of each field of the preprocessed data according to the frame structure defined in the figure 2 and the fields defined by the S2 to the S4, and combining the values to obtain the data frame. Data splitting is also performed on the preprocessed data with the data length larger than 75 bytes, and frame data of all the subframes are generated according to the definitions in S2 and S4.

And S9, grouping the generated data frames according to types and adding the data frames into a data transmission queue in sequence. The basic unit of the data queue is a data frame of a certain data type, and each element in the queue sends each frame data in turn at a specific time interval according to a first-come first-send sequence by default. If the priority is set for the data frame type field DT, sorting the data frame groups in the queue according to the set priority, and sequentially sending the corresponding frame data in each group according to the sorting order.

S10, the receiving end needs to read the data state of the receiving buffer every 1S. After the receiving buffer has received the data, the values of the relevant fields and the preprocessed data are obtained according to the data frame structure shown in fig. 2. And obtaining the data type according to the DT field in S3, and judging whether the data frame is framed according to the definition of the SN field in S4. If the frame is a single frame, acquiring the byte length of the data segment through the SN; if the data is multi-frame data and not a tail frame, advancing the data according to the length of 75 bytes; when the last frame is received, the data length of the current frame is obtained according to SN, and after all the data of the sub-frames are extracted, the data of each frame is combined to generate a complete data frame;

and S11, carrying out pretreatment reduction on the complete data generated in the S10 according to the receiving end processing method in the S6 to obtain original data, and handing the original data together with the obtained data type to specific application of an upper layer for processing.

The following further describes the present invention by taking a certain actually transmitted data as an example.

As shown in fig. 3, if a user has a group of data types 0x01, the original data with a length of 180 bytes is to be transmitted by using the beidou short message method described in the present invention. This set of data is expressed in hexadecimal (same below) as follows:

0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 42 56 52 65 7D 12 31 89 0A 0D BA FF 7D 7D 220A 0D 99 98 87

according to the steps described in the present invention, the first step requires preprocessing of the data, which involves performing escape processing of specific endianness (0x7D and 0x0D-0x0A) that continuously appear in the original data, and then amplifying the processed data to 279 bytes, wherein the specific data is as follows:

7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 42 56 52 65 7D 5D 12 31 89 0A 0D BA FF 7D 5D 7D 5D 22 0A 0D 99 98 87

according to the description of the present invention, the data length of each frame is 75 bytes at most, so the preprocessed data needs to be divided into 4 bytes for transmission, the type of the data is 0x01, and the first two bytes of each frame need to be determined according to the actual frame type and defined fields. Specifically, the data generated for each frame is:

first frame data:

41 04 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D

second frame data:

01 02 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52

third frame data:

01 03 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D

fourth frame data:

81 36 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 42 56 52 65 7D 5D 12 31 89 0A 0D BA FF 7D 5D 7D 5D 22 0A 0D 99 98 87

the generated 4 frames of data are then assembled to generate a group of transmission data queues, and the transmission data queues are sent to a transmission data buffer zone to wait for a system to transmit at a fixed frequency. When all data in the transmission is confirmed to be received (the receiving end sends an acknowledgement frame of type 0x00 to confirm that the data has been received), the content of the queue in the transmission buffer can be cleared.

Corresponding to the receiving end, it is assumed that the following data are received in sequence:

first frame data:

41 04 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D

second frame data:

01 02 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52

third frame data:

01 03 23 7D 5D 56 31 22 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 14 52 23 7D 5D 56 31 22 7D 2D 0A 7D 5D

fourth frame data:

81 36 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 22 7D 5D 41 21 34 7D 5D 42 12 7D 2D 0A 7D 5D 7D 2D 0A 7D 5D 42 56 52 65 7D 5D 12 31 89 0A 0D BA FF 7D 5D 7D 5D 22 0A 0D 99 98 87

by checking the header field of the data of each frame, it is determined that the 4 frames of data are sequentially the sub-frames of a group of data frames with the frame length of 4, and then the data content of the received 4 frames of data is extracted and recombined, so as to obtain the following content: 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 227D 5D 4121347D 5D 42127D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 1452237D 5D 5631227D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 1452237D 5631227D 2D 0A 7D 2D 0A 7D 5D 7D 5D 227D 4121347D 5D 42127D 2D 0D 7D 5D 7D 5D 227D A7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 1452237D 5D 5631227D 2A 7D 5D 7D 2D 0A 7D 5D 7D 5D 227D 4121347D 5D 42127D 2D 0A 7D 5D 7D 2D 0A 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 7D 5D 1452237D 5D 5631227D 2D 0A 7D 2D 0D 7D 2D 0A 7D 5D 7 5D 227D 5D 4121347D 5D 42127D 2D 0A 7D 5D 7D 2D 0A 7D 5D 425652657D 5D 1231890A 0D BA FF 7D 5D 7D 5D 220A 0D 999887

Next, the data is restored. If 0x7D appears, then 0x7D is removed and the following 1 byte is xor 0x20, and the restored data is:

0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 7D 14 52 23 7D 56 31 22 0D 0A 7D 0D 0A 7D 7D 7D 7D 22 7D 41 21 34 7D 42 12 0D 0A 7D 0D 0A 7D 42 56 52 65 7D 12 31 89 0A 0D BA FF 7D 7D 22 0A 0D 99 98 87

compared with the Beidou No. 2, the RDSS-DTU short message service provided by the Beidou No. 3 has the capacity expanded to 1750 bytes in the region range of each message data, can adapt to the growth and change of future astronomical site observation data, and also provides technical accumulation for other telescope remote data transmission adopting narrow-band communication, for example, the Kunlun station astronomical station of Antarctic inland ice dome A to be built in China in the future.

Based on the method, a set of transceiver is set up to carry out a remote data transmission experiment of the telescope. The experiment was tested for up to 10 months without interruption, and the test results indicate the correctness and robustness of the method. At present, the remote meteorological station adopting the method is installed in a snow mountain pasture of Changha, Qinghai, and the returned data are continuous and normal. The method can also be applied to other applications of communication in any short message mode, and has important significance for actively promoting the development of the Beidou satellite industry.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.