A method for improving the success rate of shipborne beidou short message transmission in high latitude sea area

Abstract

The application provides a method for improving the success rate of shipborne Beidou short message transmission in high-latitude sea area, which comprises the following steps: firstly, designing a coding dictionary, wherein the coding dictionary is composed of a state byte, a complete longitude byte, a complete latitude byte, a partial longitude byte and a partial latitude byte; secondly, encoding the original information to be transmitted by the message transmitting end according to the newly designed coding dictionary; thirdly, highly simplifying the message content and minimizing the message length; and fourthly, reducing the probability of error caused by interference and improving the success rate of message transmission.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite navigation and communication, in particular to a method for improving the success rate of shipborne Beidou short message transmission in high latitude sea area. BACKGROUND

[0002] During the navigation of ocean-going ships, the shipborne communication system is needed to report the navigation state of the ship and important information such as environmental parameters and operation conditions to the ship company in a timely manner. However, when the ship sails in the sea far from the land, once it encounters an abnormal space environment (such as solar magnetic explosion), almost all communication means will fail, and the ship will be in a state of short-term or long-term disconnection. During this period, the ship company cannot know the navigation state of the ship; if the ship encounters risks, it can only get the message after the abnormal space environment disappears. Influenced by the earth's magnetic field, high-energy charged particles in space will converge to the two poles of the earth's magnetic field, thereby affecting the polar ionosphere, so the communication disturbance or even blockage caused thereby is particularly serious in high latitude areas. The time of a solar magnetic storm can last for 27 days, and the time of polar communication interruption caused by intense solar activity can even last for 2 days. Therefore, when the ship sails in high latitude areas, especially in the Arctic sea, it is still important to send short messages in the event of extreme space environment anomalies, which is of great significance to the operation and management of the ship company.

[0003] Simply increasing the transmission power is of no help to solve the problem, because the intensity of solar magnetic storm is much higher than that of general communication signals. The existing technical means cannot solve the communication problem in extreme space environment. Except for strengthening the observation of solar activity, summarizing the rules of solar activity to provide accurate prediction to avoid it, there is no effective method to realize communication.

[0004] When an abnormal space environment occurs, telephone and digital communication based on artificial satellites are basically unable to maintain connection, and only short message transmission based on Beidou has the possibility of successful transmission. However, short messages also face a very high bit error rate, and more importantly, in order to ensure the correctness and safety of message transmission, general Beidou short message communication needs to encrypt the message. However, if there is even only 1 bit error in the encrypted message, the entire message will be discarded due to decryption failure. Therefore, the encryption measure increases the probability of message transmission failure.

[0005] Although simple clear text transmission does not reduce the success rate of short message transmission, it still faces the problem of communication security, and due to the lack of verification means, the receiving party cannot confirm the correctness of the message content, and cannot locate the error position, so even if the short message transmission is successful, reliable information cannot be obtained. Therefore, simple clear text transmission can improve the success rate of communication, but it cannot be directly used in actual work. SUMMARY

[0006] To solve the problem that the ship can still send short information accurately through the Beidou short message when it encounters extreme changes in the space environment in high latitude areas, especially in the Arctic sea area, the application provides a method for improving the success rate of ship-borne Beidou short message transmission in high latitude sea areas, which realizes the transmission of fault-tolerant plaintext when the ship encounters extreme environment in the polar sea area, improves the success rate of Beidou short message transmission, and greatly improves the safety of navigation.

[0007] The specific scheme is as follows:

[0008] A method for improving the success rate of ship-borne Beidou short message transmission in high latitude sea areas,

[0009] S1: According to the main navigation and related state that may occur during ship navigation, a code dictionary is prepared; the message structure is designed according to the shortest message target, and the message is composed of state bytes, complete longitude bytes and complete latitude bytes, and part of the longitude and part of the latitude bytes; the original information to be sent by the message sending end is coded to form a coded message defined as information A using the code dictionary; the coding process is carried out locally on the message sending end;

[0010] S2: Information transmission is carried out by using fault-tolerant plaintext transmission method and verification: the fault-tolerant plaintext transmission method includes information transmission process and verification process: the information transmission process is to take the information A generated by S1 as Beidou short message, transmit the Beidou short message to the message receiving end, and define the Beidou short message received by the message receiving end as information B; the verification process is to verify the information B by election method, if the verification content is consistent, it is considered that the short message transmission is successful and the information B is regarded as reliable information; the election method verification content includes two parts of verifying the coded ship state and verifying the longitude and latitude information; the verification is passed, and the reliable information B is obtained;

[0011] S3: The coded dictionary of S1 is used to decode the reliable information B in S2 to generate readable final information.

[0012] Preferably, the coded message of S1 includes 12 bytes, each byte contains 8 bits; the state byte occupies the first 5 bytes; the complete longitude occupies the 6th-7th byte; the complete latitude occupies the 8th-9th byte; and the part of the longitude and the part of the latitude occupy the 10th-12th byte.

[0013] Preferably, the state byte represents the pre-defined state information of the ship navigation, which is stored in the code dictionary in two levels of category and subclass, each occupying 4 bits.

[0014] Preferably, the state byte S1 occupies 1 byte, i.e. 8 bits, the first 4 bits store the category, which can store 1 or 2 categories, and the last 4 bits store the subcategory; the first 4 bits store the sum of the 1 or 2 categories in binary form; the first 2 bits of the last 4 bits store the subcategory of the first category, and the last 2 bits of the last 4 bits store the subcategory of the second category.

[0015] Preferably, the full longitude byte S1 occupies 2 bytes, i.e. 16 bits; the first bit stores the direction, i.e. 0 for east longitude and 1 for west longitude; the second bit is filled with 0, and if it is 1, it indicates that the full longitude byte is wrong and should be discarded; the remaining 14 bits are used to store the binary number converted from the longitude value in minutes, and the actual value range of the longitude value is 0-10799.

[0016] Preferably, the full latitude byte S1 occupies 2 bytes, i.e. 16 bits; the first bit stores the direction, i.e. 0 for north latitude and 1 for south latitude; the second and third bits are filled with 0, and if they are 1, it indicates that the latitude byte is wrong and should be discarded; the remaining 13 bits are used to store the binary number converted from the latitude value in minutes, and the actual value range of the latitude value is 0-5399.

[0017] Preferably, the partial longitude and partial latitude bytes together occupy 3 bytes, i.e. 24 bits; the partial longitude and partial latitude store the partial minutes of longitude and latitude twice, which are used to verify the partial minutes of full longitude and full latitude; the method of storing twice is that 6 bits are used to store the partial minutes of longitude / latitude, and the partial minutes of longitude twice occupy 12 bits, and the partial minutes of latitude twice occupy 12 bits.

[0018] Preferably, the method of verifying the encoded ship state S2 by using the election method is that the same state information in the byte is repeated 5 times in a message by setting the state byte to occupy 5 bytes, and the receiving end determines whether to accept and which piece of information to accept as the trusted information by comparing the differences of the 5 contents.

[0019] Preferably, the method of determining by the election method includes basic determination, extended determination, and other cases; the basic determination is that if 3-5 pieces of content are completely the same and are X, it is determined that the content of the received information is X; the extended determination is that under the premise that the basic determination fails, if 2 pieces of content are completely the same and are Y, and the other 3 pieces of content are completely different, it is determined that the content of the received information is Y; and other cases are determined as sending failure.

[0020] Preferably, the method for decoding the trusted information B in S3 is: when decoding the latitude and longitude information, for the degree part of the latitude and longitude data, it can be judged according to historical data; for the minute part, the complete latitude and longitude is compared with the partial latitude and longitude, if the latitude and longitude information cannot be decoded, the context of the decoded information is further analyzed to determine the trustworthiness of the trusted information B.

[0021] Preferably, the method for comparing the complete latitude and longitude with the partial latitude and longitude is:

[0022] If the minute data of the complete latitude and longitude is the same as 1 or 2 of the partial latitude and longitude, the complete latitude and longitude is determined as the final data;

[0023] If the minute data of the complete latitude and longitude is completely different from the data in the partial latitude and longitude, but 2 data in the partial latitude and longitude are the same, the partial latitude and longitude is determined as the final data;

[0024] If the minute data of the complete latitude and longitude is completely different from the data in the partial latitude and longitude, and 2 data in the partial latitude and longitude are also not the same, the final value c of the minute part of the latitude and longitude is:

[0025]

[0026] Let the minute part of the complete latitude and longitude be a, and the minute part of the partial latitude and longitude be b1 and b2.

[0027] The present application has the following beneficial effects:

[0028] 1. The present application provides a method for improving the success rate of shipborne Beidou short message transmission in high-latitude sea areas, which first designs a coding dictionary, the coding dictionary is composed of a state byte, a complete longitude byte and a complete latitude byte, and a partial longitude and a partial latitude byte, encodes the original information to be sent by the message sending end according to the newly designed coding dictionary, highly simplifies the message content, maximally reduces the message length, the shorter the message length, the lower the probability of error caused by interference, thereby improving the success rate of message transmission, and the information transmission after coding by the coding dictionary also ensures the security of the information.

[0029] 2. The present application provides a method for improving the success rate of shipborne Beidou short message transmission in high-latitude sea areas, S1 generates information A after coding, and transmits the Beidou short message by the fault-tolerant plaintext transmission method, in the process of transmitting the Beidou short message, the Beidou short message system only adopts the method of calculating the exclusive or checksum to perform simple inspection on the transmitted message, therefore, there are about 12.2% of inspection failure cases. Therefore, the fault-tolerant plaintext transmission method is proposed to recover all or part of the content from the 12.2% of error messages to improve the overall success rate of transmission.

[0030] The use of plaintext avoids the situation that if there is even only 1 bit error in the encrypted message, the whole message will be discarded due to decryption failure, thereby increasing the success rate of message sending.

[0031] 3. The application provides a method for improving the success rate of shipborne Beidou short message sending in high-latitude sea areas, which verifies information B in S2 by an election method, thereby improving the success rate of message sending, ensuring the integrity of communication content, and improving the reliability of accepted information. In the application, a 5-segment election method is particularly used to set the state byte to 5 bytes, and experimental analysis shows that the probability of determination failure is less than 0.20%, and the reliability is acceptable. If a 3-segment election method is used, that is, the state byte is 3 bytes, the probability of judging the error state as correct is about 1.6%, which is much higher than 0.2% of the 5-time repetition and is unacceptable. If a 7-segment election method is used, it increases 2 bytes compared with the 5-segment election method, but the probability of overall bit inversion (error) caused by electromagnetic interference increases by 6.25%, and the probability of undetectable even parity check failure (which can be utilized by the fault-tolerant plaintext transmission method) caused thereby only increases by 0.02%. The overall trend is that the more the repetition (total number of bytes) increases, the greater the additional overall error probability increases, and it is much greater than the benefit brought by the fault-tolerant plaintext transmission method proposed in the application. Therefore, considering various factors, 5-time repetition is selected, that is, the state byte is set to 5 bytes. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A flowchart of a method for improving the success rate of shipborne Beidou short message sending in high-latitude sea areas.

[0033] Figure 2 A field structure diagram of an encoded information in an embodiment. DETAILED DESCRIPTION

[0034] The application will be further described below in combination with the drawings and embodiments.

[0035] A method for improving the success rate of shipborne Beidou short message sending in high-latitude sea areas, in order to ensure successful short message sending, the whole information transmission process and state change in the application are as shown in Figure 1 The information transmission steps are as follows:

[0036] S1: preparing a coding dictionary according to the main navigation and related states that may occur during ship navigation; designing a message structure according to the shortest message target, the message being composed of a state byte, a complete longitude byte and a complete latitude byte, and a partial longitude and a partial latitude byte as shown in Figure 2 ; coding the original information to be sent by the message sending end by using the coding dictionary to form an encoded message, which is defined as information A; the coding process is performed locally at the message sending end;

[0037] The high simplification of the content of the message is realized by designing the coding dictionary, and the length of the message is minimized. The less the content is sent, the lower the probability of error caused by interference is, and thus the higher the success rate of sending is. Theoretically, the shortest length of the coded information is 1 byte, but too little information is useless. In addition, too few bytes make it impossible for the receiving end to effectively verify the correctness of the sent information. The actual maximum length of the Beidou international short message is 78 bytes, but because of the significant increase in length, the probability of error in sending is greatly increased in the same space environment. Therefore, the shortest length of the coded information designed by the present application is 12 bytes. The probability of error in sending a 12-byte message is only 15.4% of that of a 78-byte message. Therefore, limiting the length of the message can greatly improve the success rate of sending. The length of 12 bytes is the minimum length that can achieve the transmission of valuable information based on the success rate of communication and the reliability of information transmission. Each byte of the coded information has a specific meaning and function, and the length and field position are unchangeable.

[0038] S2: transmitting information by using a fault-tolerant plaintext transmission method and verifying: the fault-tolerant plaintext transmission method includes an information transmission process and a verification process; the information transmission process is to transmit the information A generated by S1 after coding as a Beidou short message, transmit the Beidou short message to a message receiving end, and define the Beidou short message received by the message receiving end as information B; the verification process is to verify the information B by using an election method. If the verification contents are consistent, it is considered that the short message is sent successfully, and the information B is regarded as a trusted information. The verification contents of the election method include two parts: verifying the coded ship state and verifying the latitude and longitude information. If the verification is passed, the information B is trusted.

[0039] S3: decoding the trusted information B in S2 by using the coding dictionary in S1 to generate readable final information.

[0040] As a preferred embodiment, the fault-tolerant plaintext transmission method in S2 means that, in the process of transmitting the Beidou short message, the Beidou short message system only uses the method of calculating the exclusive or checksum to verify the sent message. Therefore, there is about 12.2% of the verification failure. Therefore, the fault-tolerant plaintext transmission method is proposed to recover all or part of the content from the 12.2% of the error message to improve the overall success rate of sending.

[0041] In the process of transmitting short message of Beidou, the system of short message of Beidou adopts exclusive or check sum to check the sent message, so there is a certain probability to find the error in the short message and terminate the transmission of the message, thus leading to the failure of sending the short message. If the number of flipped bit (error) is odd, the error will be found by the system of short message of Beidou 100%; if the number of bit is even, there is a certain probability to be missed by the system of short message of Beidou; the content of the message transmitted in the application is 12 bytes, the content of the message plus the sent message header of 18 bytes and the check of 2 bytes is 32 bytes in total, which is 256 bits; through calculation, when the length of the message of 256 bits is subjected to 8-bit exclusive or check sum, the probability of missing the error of even number of flipped bits is 12.2% in all error conditions. The application utilizes the 12.2% of the failure check to propose the method of fault-tolerant plaintext transmission.

[0042] Although there are 12.2% of the short message sending process with errors, the errors are not completely uncorrectable. Under the pressure of the length limit of the short message, the application adopts the election method to recover the correct content from the message with even number of flipped bits.

[0043] As preferred, the method for checking the coded ship state in S2 is that: by setting the state byte to occupy 5 bytes, the same state information in the byte is repeated 5 times in a message, and the receiving end determines whether to accept and which information to accept as the trusted information by comparing the difference of the 5 contents.

[0044] 12、As preferred, the method for determining the election includes basic determination, extended determination and other conditions; the basic determination is that: if 3-5 contents are all X, it is determined that the content of the received information is X; the extended determination is that: under the premise of the failure of the basic determination, if 2 contents are all Y and the other 3 contents are all different, it is determined that the content of the received information is Y; and the other conditions are determined as sending failure. The probability of determining failure by the 5-election method in the application is less than 0.20%, and the reliability is acceptable.

[0045] As preferred, as shown in the coded byte structure diagram, Figure 2 the state byte occupies 1 byte each and is repeated 5 times, so the state byte occupies 5 bytes in total, occupying the 1st-5th bytes; the complete longitude and complete latitude byte each occupies 2 bytes, the complete longitude occupies the 6th-7th byte, and the complete longitude and latitude occupies the 8th-9th byte; the partial longitude and partial latitude occupies the 10th-12th byte.

[0046] As preferred, each status byte contains 8 bits, and the status byte stores predefined status information of the ship sailing, which is divided into two levels of category and subcategory, each occupying 4 bits; the specific content of the stored predefined status information of the ship sailing is shown in the following table:

[0047] Table 1

[0048]

[0049]

[0050] As preferred, the first 4 bits of the 8 bits of the status byte store the category, and 1 or 2 categories can be stored, and the sum of the 1 or 2 categories is converted into a binary number and stored in the first 4 bits; for example, there are both "natural disasters" and "pirates and wars", and the high four bits are 9, and the corresponding binary number is 1001; the first 2 bits of the last 4 bits store the subcategory of the first category, and the last 2 bits of the last 4 bits store the subcategory of the second category; if there is no second category, the first 2 bits are assigned 0; in particular, if the 8 bits of the status byte are all "0", it represents "all normal", and if the 8 bits of the status byte are all "1", it represents "uncategorized great danger or sinking".

[0051] As preferred, the complete longitude byte of S1 occupies 2 bytes, a total of 16 bits, the first bit of the complete longitude byte stores the direction, east longitude is 0 and west longitude is 1; the second bit is filled with 0, and if it is 1, it indicates that the complete longitude byte is wrong and should be discarded; the remaining 14 bits are used to store the binary number converted from the longitude value in minutes as the minimum unit, and the actual value range of the longitude value is 0-10799.

[0052] As preferred, the complete latitude byte of S1 occupies 2 bytes, a total of 16 bits, the first bit of the complete latitude byte stores the direction, north latitude is 0 and south latitude is 1; the second and third bits are filled with 0, and if they are 1, it indicates that the latitude byte is wrong and should be discarded; the remaining 13 bits are used to store the binary number converted from the latitude value in minutes as the minimum unit, and the actual value range of the latitude value is 0-5399.

[0053] As preferred, the partial longitude and partial latitude bytes of S1 together occupy 3 bytes, a total of 24 bits, the partial longitude and partial latitude store the partial minutes of longitude and latitude, and store twice for checking the partial minutes of the complete longitude and complete latitude; 6 bits are used to store the partial minutes of longitude / latitude, and the partial minutes of longitude occupy 12 bits twice, and the partial minutes of latitude occupy 12 bits twice;

[0054] As preferred, the method for decoding the trusted information described in S4 is: when decoding the longitude and latitude information, for the degree part of the longitude and latitude data, historical data can be referred to for judgment; for the minute part, the complete longitude and latitude and the partial longitude and latitude need to be compared: if the minute data of the complete longitude and latitude is the same as 1-2 data in the partial longitude and latitude, the complete longitude and latitude is determined as the final data; if the minute data of the complete longitude and latitude is completely different from the data in the partial longitude and latitude, but 2 data in the partial longitude and latitude are the same, the partial longitude and latitude is determined as the final data; if the minute data of the complete longitude and latitude is completely different from the data in the partial longitude and latitude, and 2 data in the partial longitude and latitude are also not the same, the minute part of the complete longitude and latitude is a, the minute part of the partial longitude and latitude is b1 and b2; the final value c of the minute part of the longitude and latitude is:

[0055]

[0056] The longitude and latitude fields are relatively secondary fields, which can be analyzed according to the information context to further determine the trustworthiness thereof. If the longitude and latitude cannot be parsed according to the above rules, it should not be regarded as a failure of the message sending.

[0057] It should be noted that the above specific embodiments can enable those skilled in the art to more fully understand the present invention, but in no way limit the present invention. Therefore, although the present invention has been described in detail with reference to the drawings and examples, those skilled in the art should understand that the present invention can still be modified or equivalently replaced, in short, all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered in the protection scope of the patent of the present invention.

Claims

1. A method for improving the success rate of shipborne Beidou short message transmission in high-latitude sea areas, characterized in that S1: A code dictionary is prepared according to the main navigation and related states that may occur during ship navigation; the message structure is designed according to the shortest message target, and the message is composed of a state byte, a complete longitude byte and a complete latitude byte, and a partial longitude and a partial latitude byte; the original information to be sent by the message sending end is coded using the code dictionary to form a coded message, which is defined as information A; The coding process is carried out locally at the message sending end; S2: Information transmission is carried out using a fault-tolerant plaintext transmission method and verification: the fault-tolerant plaintext transmission method includes an information transmission process and a verification process; the information transmission process is to transmit the information A generated by S1 coding as a Beidou short message to the message receiving end, and the Beidou short message received by the message receiving end is defined as information B; the verification process is to verify the information B by election method, if the verification content is consistent, it is considered that the short message transmission is successful and the information B is considered as trusted information; the election method verification content includes two parts of verifying the coded ship state and verifying the longitude and latitude information; the trusted information B is verified and trusted; S3: The trusted information B in S2 is decoded using the code dictionary in S1 to generate readable final information; The coded message in S1 includes 12 bytes, each byte contains 8 bits; the state byte occupies the first 5 bytes; the complete longitude occupies the 6th and 7th bytes; the complete latitude occupies the 8th and 9th bytes; the partial longitude and partial latitude occupy the 10th to 12th bytes.

2. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 1, characterized in that, The state byte represents the predefined state information of the ship during navigation, which is stored in the code dictionary in two levels of category and subcategory, each occupying 4 bits.

3. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 1, characterized in that, The state byte in S1 occupies 1 byte, which contains 8 bits, the first 4 bits store the category, which can store 1 or 2 categories, and the last 4 bits store the subcategory; the first 4 bits are converted into binary numbers after adding the 1 or 2 categories, and then stored in the first 4 bits; the first 2 bits in the last 4 bits store the subcategory of the first category, and the last 2 bits in the last 4 bits store the subcategory of the second category.

4. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 1, characterized in that, The complete longitude byte in S1 occupies 2 bytes, which contains 16 bits; the first bit of the complete longitude byte stores the direction, east longitude is 0 and west longitude is 1; the second bit is filled with 0, if it is 1, it means that the complete longitude byte is wrong and should be discarded; the remaining 14 bits are used to store the binary number converted from the longitude value in minutes as the smallest unit, the actual value range of the longitude value is 0-10799.

5. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 1, characterized in that, The complete latitude byte occupies 2 bytes, and a total of 16 bits; the first bit of the complete latitude byte stores the direction, with north latitude being 0 and south latitude being 1; the second and third bits are filled with 0, and if 1 appears, it indicates that the latitude byte is wrong and should be discarded; and the remaining 13 bits are used to store the binary number converted from the latitude value in minutes as the minimum unit, and the actual value range of the latitude value is 0-5399.

6. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 1, characterized in that, The partial longitude and partial latitude bytes jointly occupy 3 bytes, and a total of 24 bits; the partial longitude and partial latitude store the partial longitude and partial latitude in minutes and store twice, and are used to verify the partial minutes of the complete longitude and complete latitude; the method of storing twice is that 6 bits are used to store a partial minute of longitude / latitude, and the partial minutes of longitude twice occupy 12 bits, and the partial minutes of latitude twice occupy 12 bits.

7. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 1, characterized in that, The method for verifying the encoded ship state by using the election method in S2 is that: by setting that the state byte occupies 5 bytes, the same state information in the byte is repeated 5 times in a message, and the receiving end determines whether to accept and which piece of information to accept as trusted information by comparing the differences of the 5 times of contents.

8. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 7, characterized in that, The method for determining by the election method includes basic determination, extended determination and other cases; the basic determination is that: if 3-5 pieces of contents are completely the same and are X, it is determined that the content of the received information is X; the extended determination is that: on the premise that the basic determination fails, if 2 pieces of contents are completely the same and are Y, and the other 3 pieces of contents are completely different, it is determined that the content of the received information is Y; and other cases are determined as sending failure.

9. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 1, characterized in that, The method for decoding the trusted information B in S3 is that: when decoding the longitude and latitude information, for the degree part of the longitude and latitude data, it can be judged according to historical data; for the minute part, the complete longitude and latitude are compared with the partial longitude and latitude, and if the longitude and latitude information cannot be decoded, the context of the decoded information is further analyzed to determine the credibility of the trusted information B.

10. The method for improving the success rate of shipboard Beidou short message transmission in high-latitude sea areas according to claim 9, characterized in that, The method for comparing the complete longitude and latitude with the partial longitude and latitude is that: If the minute data of the complete longitude and latitude is the same as 1 or 2 of the partial longitude and latitude, the complete longitude and latitude is determined as the final data; If the minute data of the complete longitude and latitude is completely different from the data in the partial longitude and latitude, but 2 data in the partial longitude and latitude are the same, the partial longitude and latitude is determined as the final data; If the minute data of the complete longitude and latitude is completely different from the data in the partial longitude and latitude, and 2 data in the partial longitude and latitude are also not the same, the final value c of the minute part of the longitude and latitude is: Let the minute part of the complete longitude and latitude be a, and the minute part of the partial longitude and latitude be b1 and b2.

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