Data Transmission Method, Data Generation Method and GNSS Receiver

Abstract

The present invention discloses a data transmission method, a data generation method and a GNSS receiver. The data transmission method is used for a measurement system, and the measurement system includes a reference station. It is characterized in that the data transmission method includes: the reference station receives GNSS signals; the reference station generates the GNSS signals into reference station signals with a target statement structure according to a data transmission protocol, and the target statement structure includes a preamble bit, a reserved bit, a statement length bit, a data block bit and a check bit, wherein the observed value data blocks in the data block bit combine and encode the data of the GPS system and the QZSS system; the reference station broadcasts the reference station signals. The present invention can reduce the data broadcast volume of the reference station and reduce the situation of data loss and inability to broadcast complete observation data when the radio station performs differential data broadcast.

Description

Technical Field

[0001] The present invention relates to a data transmission method, a data generation method, and a GNSS receiver. Background Art

[0002] Satellite navigation and positioning technology has basically replaced ground-based radio navigation, traditional geodetic, and astronomical navigation and positioning technologies, and has promoted a new development in the fields of geodetic surveying and navigation and positioning.

[0003] GNSS (Global Navigation Satellite System) refers to the world's four major navigation and positioning systems including the US GPS, Russia's GLONASS, Europe's Galileo, and China's Beidou, which can provide users with uninterrupted high-precision global coverage of navigation signal resources, thereby realizing all-weather real-time positioning, speed measurement, and timing functions.

[0004] The real-time kinematic (RTK) technology of the global positioning system requires a base station to broadcast observation data or corrections for differential positioning. The currently more commonly used broadcast format is the RTCM 10403.3 protocol, and its Multiple Signal Messages can support the broadcast of observation data for each frequency point of GPS, GLONASS, GALILEO, SBAS, QZSS, and BeiDou. However, the data volume of this format is relatively large, and data loss may occur when using a radio station to broadcast differential data, resulting in the inability to broadcast complete observation data. When the measurement environment is poor, due to incomplete differential data, there may not be enough satellite observations to obtain a fixed solution. Another commonly used protocol is the CMR protocol developed by Trimble. This protocol initially only supported the broadcast of GPS L1 and L2 observations. Subsequently, companies such as Leica imitated the GPS format and added a broadcast format for GLONASS observation data. In 2009, Trimble developed the CMRx protocol, aiming to expand the supported systems and frequency points, but this format was not made public. In addition, information such as signal-to-noise ratio and locktime is missing from the broadcast content. Therefore, there is also a situation of insufficient broadcast observation data when using the currently publicly available CMR / CMR+ protocol. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect that the data broadcast volume of the reference station in the prior art is relatively large, and data loss and the inability to broadcast complete observation data often occur, and to provide a data transmission method, a data generation method, and a GNSS receiver that can reduce the data broadcast volume of the reference station and reduce data loss and the inability to broadcast complete observation data when using a radio station to broadcast differential data.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A data transmission method based on a data transmission protocol, the data transmission method being used for a measurement system, the measurement system including a reference station, characterized in that the data transmission method includes:

[0008] The reference station receives GNSS signals;

[0009] The reference station generates a reference station signal with a target statement structure according to the data transmission protocol for the GNSS signals, the target statement structure including a leading bit, a reserved bit, a statement length bit, a data block bit, and a check bit, wherein the observed value data block in the data block bit combines and encodes the data of the GPS system and the QZSS system;

[0010] The reference station broadcasts the reference station signal.

[0011] Preferably, the observed value data block includes a satellite observed value data block, and the reference station generating a reference station signal with a target statement structure according to the data transmission protocol includes:

[0012] The reference station obtains the satellite main frequency point pseudorange 1 ms remainder data as the satellite observed value data block according to the observed values of the satellites;

[0013] Adding the satellite main frequency point pseudorange 1 ms remainder data to the data block bit.

[0014] Preferably, the measurement system includes a rover station, and the data transmission method includes:

[0015] The rover station receives the reference station signal generated according to the data transmission protocol;

[0016] Obtaining the satellite main frequency point pseudorange 1 ms remainder data and the reference station coordinates from the reference station signal;

[0017] Obtaining satellite observed values according to the rover station ephemeris, the satellite main frequency point pseudorange 1 ms remainder data, and the reference station coordinates.

[0018] Preferably, the length of the leading bit is 8 bits, the length of the reserved bit is 6 bits, the length of the statement length bit is 10 bits, the check bit is a cyclic redundancy check bit and the length is 24 bits;

[0019] The data block bit includes an observed value data block and a base station coordinate data block, and the observed value data block includes: statement code, base station number, time, epoch end flag, satellite number bitmap, satellite frequency point bitmap, satellite observation unit bitmap, satellite observed value data block, and frequency point observed value data block;

[0020] The base station coordinate data block includes: statement code, base station number, base station ARP X coordinate value, base station ARP Y coordinate value, base station ARP Z coordinate value, and base station antenna height.

[0021] Preferably, the data transmission protocol includes a schedule table, the schedule table includes several satellite systems, each satellite includes several satellite frequency points, the length of the satellite frequency point bitmap is a target length, the target length is the same as the number of satellite frequency points of the target satellite system, and the target satellite system is the satellite system with the most satellite frequency points among the several satellite systems.

[0022] Preferably, the length of the satellite frequency point bitmap is 6 bits, the several satellite systems include GPS system, QZSS system, GLONASS system, GALILEO system and BDS system, and the GPS system and the QZSS system are regarded as one satellite system.

[0023] Preferably, the reference station includes a collection module and an acquisition module, and the data transmission method includes:

[0024] The collection module collects the setting information of the user;

[0025] The acquisition module obtains the several satellite systems according to the setting information and generates the schedule table;

[0026] The reference station obtains the satellite frequency point bitmap according to the schedule table.

[0027] The present invention also provides a data generation method based on a data transmission protocol. The data generation method is used for a measurement system, and the measurement system includes a reference station. The data generation method includes:

[0028] The reference station receives GNSS signals;

[0029] The reference station generates the reference station signals of the target statement structure according to the data transmission protocol from the GNSS signals. The target statement structure includes a preamble bit, a reserved bit, a statement length bit, a data block bit, and a check bit, wherein the observed value data blocks in the GPS system and the QZSS system in the data block bit are combined and encoded;

[0030] Among them, the length of the preamble bit is 8 bits, the length of the reserved bit is 6 bits, the length of the statement length bit is 10 bits, the check bit is a cyclic redundancy check bit and the length is 24 bits;

[0031] The data block bit includes an observed value data block and a base station coordinate data block,

[0032] The observed value data block includes: statement code, base station number, time, epoch end flag, satellite number bitmap, satellite frequency point bitmap, satellite observation unit bitmap, satellite observed value data block, and frequency point observed value data block;

[0033] The base station coordinate data block includes: statement code, base station number, base station ARP X coordinate value, base station ARP Y coordinate value, base station ARP Z coordinate value, and base station antenna height;

[0034] The data transmission protocol includes a schedule, the schedule includes several satellite systems, each satellite includes several satellite frequency points, the length of the satellite frequency point bitmap is the target length, the target length is the same as the number of satellite frequency points of the target satellite system, and the target satellite system is the satellite system with the largest number of satellite frequency points among the several satellite systems;

[0035] The length of the satellite frequency point bitmap is 6 bits, the several satellite systems include GPS system, QZSS system, GLONASS system, GALILEO system and BDS system, and the GPS system and QZSS system are regarded as one satellite system.

[0036] Preferably, the data generation method includes:

[0037] Obtain pilot bit data;

[0038] Calculate the number of satellites and frequency points of the system to be encoded;

[0039] Generate a satellite observed value data block;

[0040] Generate a frequency point observed value data block.

[0041] The present invention also provides a GNSS receiver, the GNSS receiver generates a reference station signal by using the data generation method as described above; and / or,

[0042] The GNSS receiver transmits the reference station signal by using the data transmission method as described above.

[0043] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0044] The positive and progressive effects of the present invention are as follows:

[0045] The present invention can reduce the data broadcast volume of the reference station, and reduce the situation of data loss and inability to broadcast complete observed data when the radio station broadcasts differential data. Description of the Drawings

[0046] Figure 1 It is a flowchart of the data transmission method according to Embodiment 1 of the present invention.

[0047] Figure 2 This is another flowchart of the data transmission method according to Embodiment 1 of the present invention. Detailed implementation manners

[0048] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the described embodiments.

[0049] Embodiment 1

[0050] This embodiment provides a measurement system, which includes a reference station and a rover station, and both the reference station and the rover station are GNSS receivers.

[0051] The reference station is used for:

[0052] Receiving GNSS signals;

[0053] Generating a reference station signal with a target statement structure according to a data transmission protocol, where the target statement structure includes a preamble bit, a reserved bit, a statement length bit, a data block bit, and a check bit, and the observed value data block in the data block bit combines and encodes the data of the GPS system and the QZSS system;

[0054] Broadcasting the reference station signal to the rover station.

[0055] The observed value data block includes a satellite observed value data block, and the reference station is used for:

[0056] Obtaining satellite main frequency point pseudorange 1ms remainder data as the satellite observed value data block according to the observed values of the satellites;

[0057] Adding the satellite main frequency point pseudorange 1ms remainder data to the data block bit.

[0058] The rover station is used for:

[0059] Receiving the reference station signal generated according to the data transmission protocol;

[0060] Obtaining satellite main frequency point pseudorange 1ms remainder data and reference station coordinates from the reference station signal;

[0061] Obtaining satellite observed values according to the rover station ephemeris, satellite main frequency point pseudorange 1ms remainder data, and reference station coordinates.

[0062] Among them, the length of the preamble bit is 8 bits, the length of the reserved bit is 6 bits, the length of the statement length bit is 10 bits, and the check bit is a cyclic redundancy check bit and its length is 24 bits;

[0063] The data block bits include an observation value data block and a base station coordinate data block. The observation value data block includes: statement code, base station number, time, epoch end flag, satellite number bitmap, satellite frequency point bitmap, satellite observation unit bitmap, satellite observation value data block, and frequency point observation value data block;

[0064] The base station coordinate data block includes: statement code, base station number, base station ARP X coordinate value, base station ARP Y coordinate value, base station ARP Z coordinate value, and base station antenna height.

[0065] The data transmission protocol includes a schedule. The schedule includes several satellite systems. Each satellite includes several satellite frequency points. The length of the satellite frequency point bitmap is the target length, and the target length is the same as the number of satellite frequency points of the target satellite system. The target satellite system is the satellite system with the largest number of satellite frequency points among the several satellite systems.

[0066] The length of the satellite frequency point bitmap is 6 bits. The several satellite systems include the GPS system, QZSS system, GLONASS system, GALILEO system, and BDS system. Among them, the GPS system and the QZSS system are regarded as one satellite system.

[0067] The reference station includes a collection module and an acquisition module.

[0068] The collection module is used to collect the setting information of the user.

[0069] The acquisition module is used to obtain the several satellite systems according to the setting information and generate the schedule.

[0070] The reference station is used to obtain the satellite frequency point bitmap according to the schedule.

[0071] See Figure 1 , using the above measurement system, this embodiment also provides a data transmission method. The data transmission method includes:

[0072] Step 100, the reference station receives GNSS signals;

[0073] Step 101, the reference station generates a reference station signal with a target statement structure according to the data transmission protocol. The target statement structure includes a preamble bit, a reserved bit, a statement length bit, a data block bit, and a check bit. Among them, the data of the GPS system and the QZSS system in the observation value data block of the data block bit are combined and encoded;

[0074] Step 102, the reference station broadcasts the reference station signal.

[0075] The target statement structure of the reference station signal in this embodiment includes:

[0076] The pilot bit, with a length of 8 bits, can be 1011 1100;

[0077] The reserved bit, with a length of 6 bits, can be 000000;

[0078] The statement length bit, with a length of 10 bits, is the statement length in bytes;

[0079] The data block bit, with an indefinite length, can be 0 - 123 bytes;

[0080] The check bit, specifically CRC, with a length of 24 bits, can be CRC - 24.

[0081] In this embodiment, the GPS system and the QZSS system are regarded as a system for combined coding. A system includes satellites of the GPS system and satellites of the QZSS system.

[0082] The data transmission protocol of this embodiment combines the GPS system and the QZSS system for coding, broadcasts QZSS and GPS together, reduces the overlap of header information, and thus reduces the amount of data encoded by the GPS system and the QZSS system respectively.

[0083] The observed value data block includes the satellite observed value data block. Step 101 specifically includes:

[0084] The reference station obtains the satellite main frequency point pseudorange 1 ms remainder data based on the observations of the satellites as the satellite observed value data block;

[0085] Add the satellite main frequency point pseudorange 1 ms remainder data to the data block bit.

[0086] The measurement system includes a mobile station. After step 102, it includes:

[0087] Step 103, the mobile station receives the reference station signal generated by the data transmission protocol;

[0088] Step 104, obtain the satellite main frequency point pseudorange 1 ms remainder data and the reference station coordinates from the reference station signal;

[0089] Step 105, obtain the satellite observed values based on the rover ephemeris, the satellite main frequency point pseudorange 1 ms remainder data, and the reference station coordinates.

[0090] For example, the observed value of a satellite is 24998406.359, and 1 ms = 299792.4580 meters. When encoding, only the distance of mod(24998406.359, 299792.4580) = 1.1563e+05 is broadcast, that is, the part of the pseudorange less than 1 ms. The large number part of (24998406.359 - 1.1563e+05) is not broadcast. Thus, the amount of data that needs to be broadcast in the prior art is compressed.

[0091] When the mobile station decodes to restore this value, what needs to be done is to use the base station coordinates and the rover ephemeris to calculate the distance from the base station to this satellite at the corresponding time to restore (24998406.359 - 1.1563e+05), that is, 83 * 299792.4580 (1 ms).

[0092] Specifically, the length of the pilot bit is 8 bits, the length of the reserved bit is 6 bits, the length of the statement length bit is 10 bits, and the parity bit is a cyclic redundancy check bit with a length of 24 bits;

[0093] The data block bit includes an observed value data block and a base station coordinate data block. The observed value data block includes: statement code, base station number, time, epoch end flag, satellite number bitmap, satellite frequency point bitmap, satellite observation unit bitmap, satellite observed value data block, and frequency point observed value data block;

[0094] The base station coordinate data block includes: statement code, base station number, base station ARP X coordinate value, base station ARP Y coordinate value, base station ARP Z coordinate value, and base station antenna height.

[0095] The specific fields of the observed value data block are:

[0096] Statement code, data type is uint4, range is 0 - 15. In the statement code, GPS and QZSS satellites are combined and encoded. 1 corresponds to gps+qzss, 2 corresponds to glonass, 3 corresponds to galileo, and 4 corresponds to bds.

[0097] Base station number, data type is uint8, range is 0 - 255.

[0098] Time, data type is uint18, range is 0 - 240000, which is the GPS time of the base station receiver modulo 240 seconds.

[0099] Epoch end flag, data type is bit(1), range is 0 or 1. 1 means there are still statements not broadcast at this time point, and 0 means the statements at this moment have been broadcast.

[0100] Satellite ID bitmap, data type is bit(64), and for QZSS it is 40 - 60.

[0101] Satellite frequency position bitmap, data type is bit(6).

[0102] Satellite observation unit bitmap, data type is Bit(x), and the range is X = Nsat * Nsig, where Nsat is the number of satellites and Nsig is the number of frequency points.

[0103] The number of bits of the above module: 101 + Nsat * Nsig.

[0104] Satellite observation value data block, including the 1ms remainder part of the pseudorange at the main frequency point of each satellite (marked as P0), data type is uint16, range is 0 - 65536, resolution is to distinguish 0.02 meters (approximately equal to 1 / 9 of the L1 wavelength), and the integer part supplemented by the rover is obtained by calculating the distance from the base station to the satellite at this moment through the base station coordinates and the rover ephemeris to compensate for the integer part.

[0105] The number of bits of the satellite observation value data block: 16 * Nsat.

[0106] Frequency point observation value data block, including:

[0107] The difference between the pseudorange of the Nth frequency point and P0, data type is int15, and the inter-frequency difference is 0.02 * 2^14 (about 300m), and this field does not need to be encoded for the main frequency point.

[0108] The difference between the carrier of the Nth frequency point and P0, data type is int22.

[0109] The lock time of the Nth frequency point, data type is uint4.

[0110] The signal-to-noise ratio index of the Nth frequency point, data type is uint4, range is 0 - 15, resolution is 2dB, 0 represents less than 20dB, 1 represents 20 - 22dB, 2 represents 22 - 24dB, and so on, 15 represents greater than 50dB.

[0111] The number of bits of the frequency point observation value data block: 45 * Ncell (the number of data units) - 15 * Nsat.

[0112] Total data volume: 101 + Nsat * (1 + 46 * Nsig).

[0113] The specific fields of the base station coordinate data block are:

[0114] Statement code, data type is uint4, range is 0 - 15.

[0115] Base station number, data type is uint8, range is 0 - 255.

[0116] Base station ARP X coordinate value, with the data type of int38.

[0117] Base station ARP Y coordinate value, with the data type of int38.

[0118] Base station ARP Z coordinate value, with the data type of int38.

[0119] Base station antenna height, with the data type of uint16.

[0120] Total data volume: 138 bits.

[0121] Further, the data transmission protocol includes a schedule, the schedule includes several satellite systems, each satellite includes several satellite frequency points, the length of the satellite frequency point bitmap is the target length, the target length is the same as the number of satellite frequency points of the target satellite system, and the target satellite system is the satellite system with the largest number of satellite frequency points among the several satellite systems.

[0122] Specifically, the length of the satellite frequency point bitmap is 6 bits, the several satellite systems include GPS system, QZSS system, GLONASS system, GALILEO system and BDS system, and the GPS system and QZSS system are regarded as one satellite system.

[0123] The schedule specifically includes:

[0124] Systems: GPS and QZSS (co - coded), GLONASS, GALILEO, BDS.

[0125] GPS and QZSS include frequency points L1, L2, L5, L1C, L6;

[0126] GLONASS includes frequency points G1, G2, G3;

[0127] GALILEO includes frequency points E1, E5B, E5A, E5, E6;

[0128] BDS includes frequency points B1, B2, B3, B2a, B1C, B2b.

[0129] The target length is the same as the number of satellite frequency points of the target satellite system, which is 6 in this embodiment. They are numbered 0, 1, 2, 3, 4, 5 in sequence.

[0130] Further, the reference station includes a collection module and an acquisition module, and the data transmission method includes:

[0131] The collection module collects the user's setting information;

[0132] The obtaining module obtains the several satellite systems according to the setting information and generates the attached table;

[0133] The reference station obtains the satellite frequency point bitmap according to the attached table.

[0134] The above steps can be executed before step 100.

[0135] The data volume calculation formula for the RTCM3 MSM4 format is 169 + Nsat * (18 + 49 * Nsig). The data volume calculation formula for the data transmission protocol format of this application is 101 + Nsat * (1 + 46 * Nsig). Compared with the prior art, it reduces the data broadcast volume of the reference station and reduces the situation of data loss and incomplete observation data broadcast when the radio station performs differential data broadcast.

[0136] Specifically:

[0137] For the RTCM3.3 MSM4 format, the data volume calculation is as follows: 169 + Nsat * (18 + 49 * Nsig)

[0138] GPS: 169 + 8 * (18 + 49 * 3) = 1489 bits

[0139] GLONASS: 169 + 5 * (18 + 49 * 2) = 749 bits

[0140] BDS: 169 + 12 * (18 + 49 * 3) = 2149 bits

[0141] 169 + 9 * (18 + 49 * 3) = 1654 bits

[0142] GLALILEO: 169 + 8 * (18 + 49 * 3) = 1489 bits

[0143] QZSS: 169 + 4 * (18 + 49 * 3) = 829 bits

[0144] For the format of the data transmission protocol in this embodiment, the calculation formula is: 101 + Nsat * (1 + 46 * Nsig)

[0145] GPS + QZSS: 101 + 12 * (1 + 46 * 3) = 1769 bits

[0146] GLONASS: 101 + 5 * (1 + 46 * 2) = 566 bits

[0147] GLALILEO: 101 + 8 * (1 + 46 * 3) = 1213 bits

[0148] BDS: 101 + 12 * (1 + 46 * 3) = 1769 bits

[0149] 101 + 9 * (1 + 46 * 3) = 1575 bits

[0150] As can be seen from the above results, the present application can greatly reduce the data broadcast volume of the reference station.

[0151] This embodiment also provides a data generation method based on a data transmission protocol. The data generation method is used for a measurement system, and the measurement system includes a reference station. The data generation method includes:

[0152] The reference station receives GNSS signals;

[0153] The reference station generates the GNSS signals into reference station signals with a target statement structure according to the data transmission protocol. The target statement structure includes a leading bit, a reserved bit, a statement length bit, a data block bit, and a check bit. The observed value data block in the data block bit combines and encodes the data of the GPS system and the QZSS system;

[0154] Among them, the length of the leading bit is 8 bits, the length of the reserved bit is 6 bits, the length of the statement length bit is 10 bits, and the check bit is a cyclic redundancy check bit and its length is 24 bits;

[0155] The data block bit includes an observed value data block and a base station coordinate data block,

[0156] The observed value data block includes: statement code, base station number, time, epoch end flag, satellite number bitmap, satellite frequency point bitmap, satellite observation unit bitmap, satellite observed value data block, and frequency point observed value data block;

[0157] The base station coordinate data block includes: statement code, base station number, base station ARP X coordinate value, base station ARP Y coordinate value, base station ARP Z coordinate value, and base station antenna height;

[0158] The data transmission protocol includes a schedule. The schedule includes several satellite systems. Each satellite includes several satellite frequency points. The length of the satellite frequency point bitmap is a target length, and the target length is the same as the number of satellite frequency points of the target satellite system. The target satellite system is the satellite system with the most satellite frequency points among the several satellite systems;

[0159] The length of the satellite frequency point bitmap is 6 bits. The several satellite systems include the GPS system, the QZSS system, the GLONASS system, the GALILEO system, and the BDS system. Among them, the GPS system and the QZSS system are regarded as one satellite system.

[0160] See Figure 2 , specifically, the data generation method includes:

[0161] Step 200, obtain pilot bit data;

[0162] Step 201, calculate the number of satellites and the number of frequency points of the system to be encoded;

[0163] Step 202, generate a satellite observation value data block, the integer part of the observation value of each satellite;

[0164] Step 203, generate a frequency point observation value data block, the part of the observation value of each satellite less than 1 ms, and other information.

[0165] According to the data transmission protocol, add the data in the GNSS signal and the data of the reference station to the statement structure in a format.

[0166] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples. The protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A data transmission method based on a data transmission protocol, the data transmission method being used for a measurement system, the measurement system including a reference station, characterized in that, the data transmission method includes: The reference station receives GNSS signals; The reference station generates a reference station signal with a target statement structure according to the data transmission protocol, the target statement structure including a leading bit, a reserved bit, a statement length bit, a data block bit, and a check bit, wherein the observed value data block in the data block bit combines and encodes the data of the GPS system and the QZSS system; The reference station broadcasts the reference station signal; The observed value data block includes a satellite observed value data block, and the reference station generating a reference station signal with a target statement structure according to the data transmission protocol includes: The reference station obtains the satellite main frequency point pseudorange 1ms remainder data as the satellite observed value data block according to the observed values of the satellites; Adding the satellite main frequency point pseudorange 1ms remainder data to the data block bit.

2. The data transmission method according to claim 1, characterized in that, the measurement system includes a mobile station, and the data transmission method includes: The mobile station receives the reference station signal generated according to the data transmission protocol; Obtaining the satellite main frequency point pseudorange 1ms remainder data and the reference station coordinates from the reference station signal; Obtaining satellite observed values according to the rover ephemeris, the satellite main frequency point pseudorange 1ms remainder data, and the reference station coordinates.

3. The data transmission method according to claim 1, characterized in that, The length of the leading bit is 8 bits, the length of the reserved bit is 6 bits, the length of the statement length bit is 10 bits, the check bit is a cyclic redundancy check bit and the length is 24 bits; The data block bit includes an observed value data block and a base station coordinate data block, and the observed value data block includes: statement code, base station number, time, epoch end flag, satellite number bitmap, satellite frequency point bitmap, satellite observation unit bitmap, satellite observed value data block, and frequency point observed value data block; The base station coordinate data block includes: statement code, base station number, base station ARP X coordinate value, base station ARP Y coordinate value, base station ARP Z coordinate value, and base station antenna height.

4. The data transmission method according to claim 3, characterized in that, The data transmission protocol includes a schedule, the schedule including several satellite systems, each satellite including several satellite frequency points, the length of the satellite frequency point bitmap being a target length, the target length being the same as the number of satellite frequency points of the target satellite system, the target satellite system being the satellite system with the largest number of satellite frequency points among the several satellite systems.

5. The data transmission method according to claim 4, characterized in that, The length of the satellite frequency point bitmap is 6 bits, the several satellite systems including the GPS system, the QZSS system, the GLONASS system, the GALILEO system, and the BDS system, wherein the GPS system and the QZSS system are taken as one satellite system.

6. The data transmission method according to claim 4, characterized in that, The reference station includes a collection module and an acquisition module, and the data transmission method includes: The collection module collects the setting information of the user; The acquisition module obtains the several satellite systems according to the setting information and generates the attached table; The reference station obtains the satellite frequency point map according to the attached table.

7. A data generation method based on a data transmission protocol, the data generation method is used for a measurement system, and the measurement system includes a reference station. Characterized in that The data generation method includes: The reference station receives GNSS signals; The reference station generates a reference station signal with a target statement structure according to the data transmission protocol, and the target statement structure includes a lead bit, a reserved bit, a statement length bit, a data block bit and a check bit, wherein the observed value data blocks of the GPS system and the QZSS system in the data block bit are combined and encoded; Wherein, the length of the lead bit is 8 bits, the length of the reserved bit is 6 bits, the length of the statement length bit is 10 bits, the check bit is a cyclic redundancy check bit and the length is 24 bits; The data block bit includes an observed value data block and a base station coordinate data block; The observed value data block includes: statement code, base station number, time, epoch end flag, satellite number bitmap, satellite frequency point map, satellite observation unit bitmap, satellite observation value data block and frequency point observation value data block; The base station coordinate data block includes: statement code, base station number, base station ARP X coordinate value, base station ARP Y coordinate value, base station ARP Z coordinate value and base station antenna height; The data transmission protocol includes an attached table, the attached table includes several satellite systems, each satellite includes several satellite frequency points, the length of the satellite frequency point map is a target length, and the target length is the same as the number of satellite frequency points of the target satellite system, and the target satellite system is the satellite system with the most satellite frequency points among the several satellite systems; The length of the satellite frequency point map is 6 bits, the several satellite systems include the GPS system, the QZSS system, the GLONASS system, the GALILEO system and the BDS system, and the GPS system and the QZSS system are taken as one satellite system.

8. The data generation method according to claim 7, Characterized in that The data generation method includes: Obtaining lead bit data; Calculating the number of satellites and the number of frequency points of the system to be encoded; Generating a satellite observation value data block; Generating a frequency point observation value data block.

9. A GNSS receiver, Characterized in that The GNSS receiver generates a reference station signal by using the data generation method according to claim 8; and / or The GNSS receiver transmits a reference station signal by using the data transmission method according to any one of claims 1 to 6.

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