A regional short message encoding method and a positioning method based on regional short message

Abstract

The embodiment of the present application discloses a regional short message encoding method and a positioning method based on regional short messages, which relate to the field of GNSS navigation and positioning technology. The encoding method includes: calculating the spatial signal ranging error correction number of each satellite based on the initial position of the user terminal; determining the deviation change of the pseudorange observation value of each satellite; obtaining the phase observation value deviation of each satellite; determining the broadcast satellite; encoding the spatial signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of the broadcast satellite into a regional short message. The present application increases the number of satellites broadcasting short messages by more effectively utilizing the data length of the regional short message, reduces the accuracy loss caused by encoding, and improves positioning accuracy and convergence speed. Under the premise that satellite visibility, spatial signal ranging error, pseudorange and phase deviation are all within the valid range, multiple visible satellites are selected for encoding and broadcasting, which effectively improves positioning accuracy.

Description

Technical Field

[0001] The present application relates to the field of GNSS navigation and positioning technology, and in particular to a regional short message encoding method and a positioning method based on regional short messages. Background Art

[0002] With the widespread adoption of GNSS technology, users have an urgent need for real-time, high-precision positioning services. The IGS publishes high-precision real-time orbit, clock, and hardware delay correction information, enabling users to achieve real-time, precise point positioning with decimeter- to centimeter-level accuracy.

[0003] Among them, the precise single-point positioning service system needs to broadcast enhanced information such as satellite space signal ranging error and pseudorange phase deviation. However, the current transmission methods based on the Internet and mobile communications are limited by the distribution of base stations, and coverage is insufficient in areas such as deserts and oceans. The links based on satellite communications are susceptible to interference and have low security. In contrast, Beidou short message communication does not require external communication link support, is fully autonomous and controllable, highly secure and cost-effective, and provides all-weather, all-day service capabilities. However, each Beidou regional short message has a data length limit. For example, the data length of the Beidou regional short message secondary card is 1835 bits, which makes it impossible to use conventional encoding schemes to achieve precise positioning based on regional short messages.

[0004] Based on this, a new coding scheme is needed to transmit the satellite space signal ranging error and pseudorange phase deviation for real-time precise point positioning. Summary of the Invention

[0005] The embodiments of the present application provide a method for encoding a regional short message and a positioning method based on a regional short message, which are used to address the defects of the above-mentioned related technologies. The technical solutions are as follows:

[0006] In a first aspect, an embodiment of the present application provides a method for encoding a regional short message, which is applied to a server, and the method includes:

[0007] Determine the initial position of the user terminal based on the regional short message sent by the user terminal, and calculate the space signal ranging error correction number of each satellite according to the initial position;

[0008] Determine an initial value of the pseudorange observation value deviation of each satellite, and subtract the pseudorange observation value deviation of each satellite from the corresponding initial value of the pseudorange observation value deviation to obtain a change in the pseudorange observation value deviation of each satellite; and obtain a phase observation value deviation of each satellite;

[0009] Determining the broadcasting satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value bias, and the phase observation value bias;

[0010] The space signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of the broadcasting satellite are encoded into a server-side regional short message;

[0011] The data length of the short message in the server area is less than a preset short message data length threshold.

[0012] In a preferred embodiment of the first aspect, the server-side regional short message includes a message header, satellite correction information, and a CRC check code in sequence;

[0013] The message header includes a synchronization code, a time identifier, and a satellite identifier in sequence;

[0014] The satellite correction information includes, in sequence, the ephemeris age of each of the broadcasting satellites, the space signal ranging error correction number of each of the broadcasting satellites, the pseudorange observation value deviation change, and the phase observation value deviation.

[0015] In a preferred solution of the first aspect, the satellite identifier includes an identification bit of each satellite arranged in a preset order, the identification bit of the broadcasting satellite is 1, and the identification bit of the non-broadcasting satellite is 0;

[0016] The generating of the server-side regional short message based on the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation of the broadcasting satellite includes:

[0017] Filling the ephemeris age, space signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of the corresponding broadcast satellite into the satellite correction information based on the order of the satellite identifiers;

[0018] The server area short message is generated by combining the message header, the satellite correction information, and the CRC check code.

[0019] In a preferred solution of the first aspect, the pseudorange observation value deviation change of the broadcasting satellite includes the pseudorange observation value deviation change of the first frequency point and the pseudorange observation value deviation change of the second frequency point, and the phase observation value deviation of the broadcasting satellite includes the phase observation value deviation of the first frequency point and the phase observation value deviation of the second frequency point.

[0020] In a preferred solution of the first aspect, determining the broadcasting satellite based on the visibility, space signal ranging error correction number, pseudorange observation value bias, and phase observation value bias of each satellite includes:

[0021] The visibility of each satellite is determined based on the initial position, and a satellite that meets the visibility requirements, has a corresponding space signal ranging error correction number within a preset space signal ranging error correction number range, has a corresponding pseudorange observation value deviation within a preset pseudorange observation value deviation range, and has a corresponding phase observation value deviation within a preset phase observation value deviation range is selected as the broadcast satellite.

[0022] In a preferred solution of the first aspect, the encoding method of the broadcast satellite's signal-in-space ranging error correction number, pseudorange observation value deviation change, and phase observation value deviation in the server-side regional short message is determined by the following method, including:

[0023] Determine the coding scale ratio of the space signal ranging error correction number, the pseudorange observation value deviation change and the phase observation value deviation;

[0024] Determining a coding scale of the space signal ranging error correction number based on a coding scale ratio of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation;

[0025] The coding scales of the pseudorange observation value deviation change and the phase observation value deviation are respectively calculated based on the determined coding scale of the space signal ranging error correction number and the coding scale ratio. The coding data lengths of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation are respectively determined based on the valid ranges of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation.

[0026] In a second aspect, an embodiment of the present application further provides a positioning method based on regional short messages, which is applied to a user terminal and includes:

[0027] Obtaining a regional short message generated by the regional short message encoding method provided by the first aspect and sent by the server;

[0028] Decoding the server-side regional short message to obtain the space signal ranging error correction number, pseudorange observation value deviation change, and phase observation value deviation of each broadcasting satellite;

[0029] Obtaining a preset initial value of the pseudorange observation value deviation of each of the broadcasting satellites, and adding a change in the pseudorange observation value deviation to the initial value of the pseudorange observation value deviation to obtain the pseudorange observation value deviation of each of the broadcasting satellites;

[0030] Obtaining a pseudorange observation value and a phase observation value of each of the broadcasting satellites, correcting the corresponding pseudorange observation value by the pseudorange observation value deviation, and correcting the corresponding phase observation value by the phase observation value deviation, to obtain a corrected pseudorange and phase for each of the broadcasting satellites;

[0031] Based on the corrected pseudorange and phase, the wide lane ambiguity is calculated and fixed by applying the MW combined observation value, and the narrow lane ambiguity is calculated and fixed based on the real-time precise point positioning algorithm;

[0032] The location coordinates of the user terminal are calculated.

[0033] In a third aspect, an embodiment of the present application further provides a regional short message encoding device, including:

[0034] A data module is used to determine the initial position of the user terminal based on the regional short message sent by the user terminal, and calculate the space signal ranging error correction number of each satellite based on the initial position;

[0035] The data module is further configured to determine an initial value of the pseudorange observation deviation of each satellite, and to obtain a change in the pseudorange observation deviation of each satellite by subtracting the pseudorange observation deviation of each satellite from the corresponding initial value of the pseudorange observation deviation; and to obtain a phase observation deviation of each satellite;

[0036] A satellite selection module is used to determine the broadcast satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value deviation and the phase observation value deviation;

[0037] A regional short message encoding module is used to generate a server-side regional short message based on the space signal ranging error correction number, the pseudorange observation value deviation change and the phase observation value deviation of the broadcasting satellite;

[0038] The data length of the short message in the server area is less than a preset short message data length threshold.

[0039] In a fourth aspect, an embodiment of the present application further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and runnable on the processor, wherein when the processor executes the program, the first aspect of the embodiment of the present application or any one of the implementation methods of the first aspect or the method provided by the second aspect is implemented.

[0040] In a fifth aspect, the present application also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, it implements the first aspect of the embodiment of the present application or any one of the implementation methods of the first aspect or the method provided by the second aspect.

[0041] The beneficial effects of the technical solutions provided by some embodiments of the present application include at least:

[0042] The embodiments of the present application provide a regional short message encoding method and a positioning method based on regional short messages. This application makes more effective use of the data length of regional short messages and greatly increases the number of satellites broadcasting a single short message, further reducing the accuracy loss caused by encoding and improving the accuracy and convergence speed of positioning. Under the premise of ensuring that satellite visibility, spatial signal ranging error, pseudorange observation value deviation, and phase observation value deviation are all within the effective range, multiple visible satellites can be selected for encoding and broadcasting, which can be adapted to the precise single-point positioning of the three positioning and navigation systems of GPS, Galileo, and Beidou, and can effectively improve positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 This is a flow chart of a method for encoding regional short messages according to an embodiment of the present application;

[0045] Figure 2 This is a flow chart of a positioning method based on regional short messages according to an embodiment of the present application;

[0046] Figure 3 This is a structural diagram of a regional short message encoding device provided in an embodiment of the present application;

[0047] Figure 4 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0049] The terms "including" and "having," and any variations thereof, in the specification and claims of this application and the accompanying drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or modules is not limited to the listed steps or modules, but may optionally include steps or modules not listed, or may optionally include other steps or modules inherent to the process, method, product, or apparatus.

[0050] It should be noted that the terms "first" and "second" used in this application are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understood that the terms "first" and "second" may interchangeably represent a specific order or precedence, where permitted. It should be understood that the objects distinguished by "first" and "second" may interchangeably represent a specific order or precedence, where appropriate, such that the embodiments of the present application described herein can be implemented in an order other than that described or illustrated herein.

[0051] It can be understood that the regional short message encoding method and the positioning method based on regional short messages provided in the embodiments of the present application are applied to positioning and navigation application scenarios, and the user's precise location coordinates are determined through two-way data transmission between the user and the server.

[0052] Specifically, the server providing positioning services receives regional short messages sent by the user end via satellite. The user end includes but is not limited to mobile phones, tablets, navigators and other devices. The server can be used to execute the regional short message encoding method provided in this application to generate a server regional short message, and return the server regional short message to the user end via satellite.

[0053] Specifically, the user terminal can send a regional short message to the server terminal via a satellite, and receive the server regional short message forwarded by the server terminal via a satellite, and obtain the coordinates of the user terminal's location based on the decoding result of the regional short message sent by the user terminal.

[0054] Understandably, while there are currently four major global satellite navigation systems in the world—GPS, BDS, Galileo, and GLONASS—my country's BeiDou satellite navigation system is the only one capable of simultaneously achieving real-time positioning and short message communication, providing users with all-weather high-precision positioning, precise timing, and real-time short message communication over large areas and long distances. BeiDou's short message communication service is fully autonomous and controllable, independent of external communication links, and supports two-way data transmission between users and between users and ground control centers. The BeiDou-3 system's short message communication service includes global short messages and regional short messages. Regional short messages serve China and surrounding areas, but the data length of a single short message is limited. The communication capacity of the secondary card for regional short messages is 1835 bits (approximately 131 Chinese characters), making it difficult to achieve precise positioning using regional short messages based on conventional coding schemes.

[0055] The present application is described in detail below with reference to specific embodiments.

[0056] Next, combine Figure 1 Taking the regional short message encoding method executed by the server as an example, the regional short message encoding method provided by the embodiment of the present application is introduced. The regional short message encoding method includes the following steps:

[0057] S101, determining the initial position of the user terminal based on the regional short message sent by the user terminal, and calculating the space signal ranging error correction number of each satellite according to the initial position.

[0058] Specifically, the regional short message sent by the user terminal is forwarded to the service terminal by the satellite. The regional short message is used to determine the initial position of the user terminal, and the accuracy of the initial position is relatively low.

[0059] Specifically, the space signal ranging error correction number of each satellite can be calculated by the following methods, including:

[0060] Obtain the real-time satellite orbit and clock error, broadcast ephemeris, obtain the real-time satellite orbit and clock error correction at time t0, and then calculate the satellite orbit correction δx in the Earth-centered Earth-fixed coordinate system ECEF s ,

[0061] δx s =[e r , e a , e c ]·δO;

[0062]

[0063] Where, δO=[δO r δO a δO a ] T is the satellite orbit state space representation (SSR) at the current time t, r represents the satellite position in the ECEF coordinate system obtained from the satellite broadcast ephemeris, represents the satellite velocity in the ECEF coordinate system obtained from the satellite broadcast ephemeris, e r , e a , e c They represent the unit vectors of the radial, tangential and normal axes of the orbital coordinate system in the inertial system respectively;

[0064] Further calculation is performed to obtain the space signal ranging error correction number at the current time t It can be expressed as:

[0065]

[0066] Among them, e represents the unit vector from the satellite to the user end, x r and x sThey represent the user’s initial position obtained from the regional short message and the satellite position calculated from the broadcast ephemeris, respectively. δC represents the satellite clock error state-space representation (SSR) at the current time t, and c represents the speed of light.

[0067] It can be understood that the satellite broadcast ephemeris involved in the calculation should be consistent with the satellite broadcast ephemeris used for user-side positioning, and the ephemeris age of the calculated space signal ranging error correction number is the ephemeris age of the broadcast ephemeris involved in the calculation of the corresponding satellite.

[0068] S102: Determine the initial value of the pseudorange observation bias of each satellite, subtract the pseudorange observation bias (Observable-specific Signal Bias, OSB) of each satellite from the corresponding initial value of the pseudorange observation bias to obtain the change in the pseudorange observation bias of each satellite; and obtain the phase observation bias of each satellite.

[0069] Specifically, the initial value of the pseudorange observation value deviation of each satellite can be selected according to actual conditions. For example, the pseudorange observation value deviation of the first day in an observation cycle is selected as the above initial value of the pseudorange observation value deviation.

[0070] S103, determining the broadcasting satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value deviation and the phase observation value deviation.

[0071] Specifically, the visibility of each satellite is determined based on the initial position of the user terminal, and satellites that meet the visibility requirements, whose corresponding space signal ranging error correction number is within the preset space signal ranging error correction number range, whose corresponding pseudorange observation value deviation is within the preset pseudorange observation value deviation range, and whose corresponding phase observation value deviation is within the preset phase observation value deviation range are selected as broadcast satellites.

[0072] Specifically, the broadcasting satellite may be selected from GPS satellites and / or Galileo satellites and / or BeiDou satellites, which is not limited in the embodiments of the present application.

[0073] Specifically, when one of the spatial signal ranging error correction number, pseudorange observation value deviation or phase observation value deviation of a satellite exceeds the corresponding valid range, the corresponding satellite does not meet the requirements and will not be used as a broadcasting satellite.

[0074] Specifically, visibility can be understood as being able to directly observe the corresponding satellite from the initial position of the user terminal. For example, the visibility condition can be set as follows: the satellite elevation angle cutoff angle is 10°, and satellites greater than the cutoff elevation angle are visible satellites, otherwise they are non-visible satellites.

[0075] It is understandable that, under normal circumstances, the number of visible satellites in each epoch of a day does not exceed 30, so the total number of broadcast satellites in each epoch is at most 30.

[0076] S104: Generate a server-side regional short message based on the broadcast satellite's space signal ranging error correction number, pseudorange observation value deviation change, and phase observation value deviation.

[0077] Specifically, the server-side regional short message includes a message header, satellite correction information, and a CRC check code, as shown in Table 1:

[0078] Table 1 Coding format

[0079]

[0080]

[0081] In some embodiments, the message header can be set to 120 bits, the satellite correction information to 1650 bits, the CRC check code to 24 bits, and the communication capacity of the Beidou regional short message secondary card to 1835 bits. The sum of the above three, 1794 bits, is less than the communication capacity.

[0082] Specifically, the data length of each short message is 1835 bits, and correction information of up to 30 satellites can be broadcast. In specific implementation, if the number of satellites that meet the requirements is less than 30, only the corresponding information of the satellites that meet the requirements will be broadcast.

[0083] The message header includes a synchronization code, a time identifier, and a satellite identifier, as shown in Table 2:

[0084] Table 2 Regional short message header

[0085] parameter bits scale Effective range unit Remark Synchronous code 8 1 Marks the start of a data packet Time stamp 12 1 0-4095 Second Seconds within hour Satellite identification 100 1 total 120

[0086] Specifically, the header file consists of an 8-bit synchronization code, a 12-bit time identifier, and a 100-bit satellite identifier. The synchronization code is used to identify the start of a data packet.

[0087] In some embodiments, bits 1-35 of the 100-bit satellite identifier represent GPS satellites, bits 36-65 represent Galileo satellites, and bits 66-100 represent BDS satellites. A value of 0 indicates that correction information for that satellite is not broadcast, while a value of 1 indicates that correction information for that satellite is broadcast. The synchronization code, time stamp, and satellite identifier together comprise 120 bits. Correction information includes the satellite's signal-in-space ranging error correction, pseudorange observation deviation change, and phase observation deviation.

[0088] It is understandable that the above 100-bit satellite identifier is only used as an example. In practice, the number of each type of satellite can be adaptively adjusted according to the actual number of satellites. For example, there are currently 32 GPS satellites, and new satellites may be launched in the future. Therefore, the 1-35-bit satellite identifier is used here to indicate whether the corresponding GPS satellite is selected as the broadcast satellite, and the identification bit is reserved.

[0089] It is understandable that the identification bits that do not correspond to actual GPS satellites are set to 0.

[0090] In some embodiments, the satellite correction information includes the ephemeris age and correction information of each broadcasting satellite. The correction information is the space signal ranging error correction number, the pseudorange observation value deviation change and the phase observation value deviation of each broadcasting satellite. Specifically, the ephemeris age, space signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of the corresponding broadcasting satellite are filled into the satellite correction information in sequence based on the order of satellite identification.

[0091] In some embodiments, the broadcast satellite's pseudorange observation value deviation change includes the pseudorange observation value deviation change of the first frequency point and the pseudorange observation value deviation change of the second frequency point, and the broadcast satellite's phase observation value deviation includes the phase observation value deviation of the first frequency point and the phase observation value deviation of the second frequency point.

[0092] For example, the encoding format of a satellite's regional short message is shown in Table 3:

[0093] Table 3 Coding format of a satellite's regional short message

[0094] parameter bits Dimensions (unit: cm) Effective range (unit: meter) Ephemeris age 8 1 0-255 Space signal ranging error correction factor 13 0.2 ±8.19 Change of pseudo-range OSB at the first frequency point 7 1.6 / 1.4 / 2.0 ±1.02 / 0.89 / 1.28 Change of pseudo-range OSB at the second frequency point 7 1.6 / 1.4 / 2.0 ±1.02 / 0.89 / 1.28 First frequency phase OSB 10 0.2 ±1.02 Second frequency phase OSB 10 0.2 ±1.02 1 satellite total 55

[0095] For example, when broadcasting correction information for 30 satellites, the generated server-side regional short message includes, in order, a message header, correction information for satellite 1, correction information for satellite 2, ..., correction information for satellite n, ..., correction information for satellite 30, and a CRC checksum. The order of satellites 1-30 is the same as the order of the satellite identifiers in the message header.

[0096] As shown in Table 3, the data length of one satellite is 55 bits, and the total data length of 30 satellites is 1650 bits.

[0097] In some embodiments, the coding scale of each correction information can be determined based on the impact of the spatial signal ranging error, the change in pseudorange observation value deviation, and the coding error of the phase observation value deviation on the fixation of widelane and narrowlane ambiguities and the impact on positioning accuracy. The specific analysis is as follows:

[0098] Wide lane ambiguity N MW It can be expressed as:

[0099]

[0100] Among them, the parameter λ MW =c / (f1-f2), parameter λ NL =c / (f1+f2), c is the speed of light, P1 is the pseudorange observation value of the first frequency point, P2 is the pseudorange observation value of the second frequency point, L1 is the phase observation value of the first frequency point, and L2 is the phase observation value of the second frequency point.

[0101] The pseudorange and phase OSB can be modified directly on the pseudorange and phase observations. Therefore, the ratio of the impact of the coding error (in meters) of the first-frequency pseudorange observation deviation change, the second-frequency pseudorange observation deviation change, the first-frequency phase observation deviation, and the second-frequency phase observation deviation on the wide-lane ambiguity is:

[0102]

[0103] Exemplarily, the influence ratio is calculated for each type of satellite. For example, it can be calculated that the influence ratio of the change in pseudorange observation value bias and the coding error of the phase observation value bias of GPS on the wide lane ambiguity is approximately equal to 1:8, the influence ratio of the change in pseudorange observation value bias and the coding error of the phase observation value bias of Galileo on the wide lane ambiguity is approximately equal to 1:7, and the influence ratio of the change in pseudorange observation value bias and the coding error of the phase observation value bias of Beidou satellite on the wide lane ambiguity is approximately equal to 1:10.

[0104] The narrow lane ambiguity can be expressed as:

[0105]

[0106] When the wide-lane ambiguity is successfully fixed, the error of the narrow-lane ambiguity is only affected by the error of the dual-frequency ionosphere-free combined floating ambiguity.

[0107] Furthermore, both the phase observation bias and the signal-in-space ranging error are directly modified in the observation equations for the corresponding frequencies. Therefore, the coding error in the phase observation bias and the signal-in-space ranging error correction have a 1:1 impact on positioning. Furthermore, the weighting of pseudorange and phase observations is 1:100, so the impact of the pseudorange observation bias change and the coding error in the phase observation bias on positioning accuracy is also 1:100.

[0108] It can be understood that after considering factors such as satellite visibility, effective range of correction information, coding scale, coding loss, etc., the embodiment of the present application determines the optimal single short message broadcast satellite space signal ranging error, pseudorange observation value deviation change, and phase observation value deviation coding format, as shown in Table 3 above.

[0109] For example, using a GPS satellite as an example, it is easy to determine that the coding scale of the spatial signal ranging error is 0.2 cm. Based on the coding scale ratio of 1:8:8:1:1 for each correction number determined in the above embodiment, the coding scales of the deviation change of the pseudorange observation value at the first frequency point, the deviation change of the pseudorange observation value at the second frequency point, the deviation of the phase observation value at the first frequency point, and the deviation of the phase observation value at the second frequency point are 1.6 cm, 1.6 cm, 0.2 cm, and 0.2 cm, respectively. The effective range A of the correction information, the coding scale m, and the encoded data length n are related by the following equation: A = m × 2^(n-1). Based on the effective range A of the spatial signal ranging error correction information of ±8.19 m and the coding scale of 0.2 cm, the encoded data length can be calculated to be 13 bits.

[0110] In some embodiments, if the combined length of the message header and satellite correction information is not an integer number of bytes, zeros are added before the CRC checksum to make the total length of the short message after encoding an integer number of bytes. Finally, a 24-bit CRC checksum is calculated and added to the end of the short message to form a complete short message.

[0111] See next Figure 2 , is a flow chart of a positioning method based on regional short messages provided in an embodiment of the present application. Figure 2 As shown, the method may include:

[0112] S201: Acquire a regional short message sent by a server and generated based on the regional short message encoding method provided in the above embodiment.

[0113] S202: Decode the server-side regional short message to obtain the space signal ranging error correction number, pseudorange observation value deviation change, and phase observation value deviation of each broadcasting satellite.

[0114] S203: Obtain an initial value of the pseudorange observation value deviation preset for each of the broadcasting satellites, add the pseudorange observation value deviation change to the initial value of the pseudorange observation value deviation, and obtain the pseudorange observation value deviation of each of the broadcasting satellites.

[0115] S204, obtaining the pseudorange observation value and phase observation value of each of the broadcasting satellites, correcting the corresponding pseudorange observation value by the pseudorange observation value deviation, and correcting the corresponding phase observation value by the phase observation value deviation, to obtain the corrected pseudorange and phase of each of the broadcasting satellites.

[0116] S205 , based on the corrected pseudorange and phase, the wide lane ambiguity is calculated and fixed by applying the MW combined observation value, and the narrow lane ambiguity is calculated and fixed based on the real-time precise point positioning algorithm.

[0117] S206: Calculate and obtain the location coordinates of the user terminal.

[0118] In some embodiments, the observation equation using the space signal ranging error and pseudorange phase deviation is:

[0119]

[0120] Among them, P IF and L IF represents the pseudorange observation value and carrier phase observation value of the ionosphere-free combination, and They represent the pseudorange observation value deviation and phase observation value deviation of the ionosphere-free combination, ρ represents the geometric distance from the satellite to the user end calculated by the broadcast ephemeris, Δρ represents the space signal ranging error correction number, c represents the speed of light in vacuum, dt r and dt s are the receiver and satellite broadcast clock errors, T is the tropospheric delay, and λ IF represents the wavelength of the combined observation, N IF represents the ionospheric-free combined ambiguity, and Represents the residual error.

[0121] The embodiments of the present application support real-time ambiguity fixation, making more efficient use of the data length of short messages in the Beidou region, significantly increasing the number of satellites that can be broadcast in a single short message, further reducing the accuracy loss caused by coding, and improving positioning accuracy and convergence speed. Based on the principle that pseudorange observation value deviation and phase deviation accuracy affect ambiguity fixation, the coding scale and data length of the spatial signal ranging error, the pseudorange observation value deviation change, and the phase observation value deviation are adjusted to minimize the impact of coding loss on ambiguity fixation and positioning accuracy, thereby improving positioning accuracy.

[0122] In some embodiments, the positioning accuracy of the GPS / Galileo / BDS three systems of the IGS station in the embodiment of the present application in the E / N / U directions can reach 0.92 / 0.89 / 3.39 cm respectively.

[0123] Among them, E stands for EAST, N stands for NORTH, and U stands for UP, which means the vertical upward direction.

[0124] See next Figure 3 , is a schematic diagram of the structure of a regional short message encoding device provided by an exemplary embodiment of the present application. The device can be implemented as all or part of a terminal through software, hardware, or a combination of both, and can also be integrated into a server as an independent module. The regional short message encoding device in the embodiment of the present application can be applied to a terminal or the cloud. The device 30 includes a data module 310, a satellite selection module 320, and a regional short message encoding module 330, wherein:

[0125] A data module is used to determine the initial position of the user terminal based on the regional short message sent by the user terminal, and calculate the space signal ranging error correction number of each satellite based on the initial position;

[0126] The data module is further configured to determine an initial value of the pseudorange observation deviation of each satellite, and to obtain a change in the pseudorange observation deviation of each satellite by subtracting the pseudorange observation deviation of each satellite from the corresponding initial value of the pseudorange observation deviation; and to obtain a phase observation deviation of each satellite;

[0127] A satellite selection module is used to determine the broadcast satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value deviation and the phase observation value deviation;

[0128] A regional short message encoding module is used to generate a server-side regional short message based on the space signal ranging error correction number, the pseudorange observation value deviation change and the phase observation value deviation of the broadcasting satellite;

[0129] The data length of the short message in the server area is less than a preset short message data length threshold.

[0130] It should be noted that the apparatus 30 provided in the above embodiment, when performing the regional short message encoding method, is merely illustrated by the division of the aforementioned functional modules. In actual applications, the aforementioned functions can be assigned to different functional modules as needed, i.e., the internal structure of the device can be divided into different functional modules to perform all or part of the functions described above. Furthermore, the apparatus provided in the above embodiment and the regional short message encoding method embodiment are based on the same concept. The implementation process is detailed in the method embodiment and will not be further described here.

[0131] An embodiment of the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the method of any of the above embodiments are implemented.

[0132] See Figure 4 , is a structural block diagram of an electronic device provided in an embodiment of the present application.

[0133] like Figure 4 As shown, the electronic device 400 includes a processor 401 and a memory 402 .

[0134] In the embodiment of the present application, the processor 401 is the control center of the computer system and can be the processor of a physical machine or the processor of a virtual machine. The processor 401 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 401 can be implemented in the form of at least one hardware selected from the group consisting of a DSP (Digital Signal Processing), an FPGA (Field-Programmable Gate Array), and a PLA (Programmable Logic Array).

[0135] The processor 401 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state.

[0136] The memory 402 may include one or more computer-readable storage media, which may be non-transitory. The memory 402 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments of the present application, the non-transitory computer-readable storage medium in the memory 402 is used to store at least one instruction, which is used to be executed by the processor 401 to implement the method in the embodiment of the present application.

[0137] In some embodiments, the electronic device 400 further includes a peripheral device interface 403 and at least one peripheral device. The processor 401, memory 402, and peripheral device interface 403 may be connected via a bus or signal lines. Each peripheral device may be connected to the peripheral device interface 403 via a bus, signal lines, or circuit boards. Specifically, the peripheral devices include a display screen 404, a camera 405, and an audio circuit 406. The peripheral device interface 403 may be used to connect at least one I / O (Input / Output)-related peripheral device to the processor 401 and memory 402.

[0138] In some embodiments of the present application, the processor 401, the memory 402, and the peripheral device interface 403 are integrated on the same chip or circuit board; in some other embodiments of the present application, any one or two of the processor 401, the memory 402, and the peripheral device interface 403 may be implemented on separate chips or circuit boards. This embodiment of the present application is not specifically limited to this.

[0139] Display screen 404 is used to display a user interface (UI). This UI may include graphics, text, icons, videos, or any combination thereof. If display screen 404 is a touch screen display, it may also be capable of collecting touch signals on or above the surface of display screen 404. This touch signal may be input as a control signal to processor 401 for processing. In this case, display screen 404 may also be used to provide virtual buttons and / or a virtual keyboard, also known as soft buttons and / or a soft keyboard.

[0140] In some embodiments of the present application, the display screen 404 can be one, provided on the front panel of the electronic device 400; in other embodiments of the present application, the display screen 404 can be at least two, provided on different surfaces of the electronic device 400 or in a folding design; in still other embodiments of the present application, the display screen 404 can be a flexible display screen, provided on a curved surface or a folding surface of the electronic device 400. The display screen 404 can even be provided in a non-rectangular irregular shape, i.e., a special-shaped screen. The display screen 404 can be made of materials such as LCD (Liquid Crystal Display) and OLED (Organic Light-Emitting Diode).

[0141] The camera 405 is used to capture images or videos. Optionally, the camera 405 includes a front camera and a rear camera. Typically, the front camera is arranged on the front panel of the electronic device, and the rear camera is arranged on the back of the electronic device. In some embodiments, there are at least two rear cameras, which are any one of a main camera, a depth of field camera, a wide-angle camera, and a telephoto camera, so as to realize the fusion of the main camera and the depth of field camera to realize the background blur function, the fusion of the main camera and the wide-angle camera to realize panoramic shooting and VR (Virtual Reality) shooting function or other fusion shooting functions. In some embodiments of the present application, the camera 405 may also include a flash. The flash can be a single-color temperature flash or a dual-color temperature flash. A dual-color temperature flash refers to a combination of a warm light flash and a cold light flash, which can be used for light compensation at different color temperatures.

[0142] Audio circuit 406 may include a microphone and a speaker. The microphone is used to collect sound waves from the user and the environment, convert the sound waves into electrical signals, and input them into processor 401 for processing. For stereo sound collection or reduction, multiple microphones may be provided, located in different parts of electronic device 400. The microphone may also be an array microphone or an omnidirectional microphone.

[0143] Power supply 407 is used to power the various components of electronic device 400. Power supply 407 can be AC ​​power, DC power, a disposable battery, or a rechargeable battery. When power supply 407 includes a rechargeable battery, the rechargeable battery can be a wired rechargeable battery or a wireless rechargeable battery. A wired rechargeable battery is a battery that is charged via a wired line, while a wireless rechargeable battery is a battery that is charged via a wireless coil. The rechargeable battery can also be used to support fast charging technology.

[0144] The electronic device structure block diagram shown in the embodiment of the present application does not constitute a limitation on the electronic device 400. The electronic device 400 may include more or fewer components than shown in the figure, or combine certain components, or adopt a different component arrangement.

[0145] The present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method of any of the aforementioned embodiments. The computer-readable storage medium may include, but is not limited to, any type of disk, including a floppy disk, an optical disk, a DVD, a CD-ROM, a microdrive, a magneto-optical disk, a ROM, a RAM, an EPROM, an EEPROM, a DRAM, a VRAM, a flash memory device, a magnetic card or an optical card, a nanosystem (including a molecular memory IC), or any type of medium or device suitable for storing instructions and / or data.

[0146] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the above technical solution, in essence, or the part that contributes to the relevant technology, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A regional short message encoding method, characterized in that: Applied to the server, the method includes: Determine the initial position of the user terminal through the regional short message sent by the user terminal, and calculate the space signal ranging error correction number of each satellite based on the initial position; Determine an initial value of the pseudorange observation value deviation of each satellite, and subtract the pseudorange observation value deviation of each satellite from the corresponding initial value of the pseudorange observation value deviation to obtain a change in the pseudorange observation value deviation of each satellite; and obtain a phase observation value deviation of each satellite; Determining the broadcasting satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value bias, and the phase observation value bias; The space signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of the broadcasting satellite are encoded into a server-side regional short message; The data length of the short message in the server area is less than a preset short message data length threshold; The server-side regional short message includes a message header, satellite correction information and a CRC check code in sequence; The message header includes a synchronization code, a time identifier, and a satellite identifier in sequence; The satellite correction information includes, in sequence, the ephemeris age of each broadcast satellite, the space signal ranging error correction number of each broadcast satellite, the pseudorange observation value deviation change, and the phase observation value deviation; the total data length of the satellite correction information is 1650 bits, and the data length of each satellite is 55 bits; The satellite identification includes an identification bit of each satellite arranged in a preset order, the identification bit of the broadcasting satellite is 1, and the identification bit of the non-broadcasting satellite is 0; The generating of the server-side regional short message based on the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation of the broadcasting satellite includes: Filling the ephemeris age, space signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of the corresponding broadcast satellite into the satellite correction information based on the order of the satellite identifiers; Combining the message header, the satellite correction information, and the CRC check code to generate the server-side regional short message; The broadcast satellite pseudorange observation value deviation variation includes the pseudorange observation value deviation variation of the first frequency point and the pseudorange observation value deviation variation of the second frequency point, and the broadcast satellite phase observation value deviation includes the phase observation value deviation of the first frequency point and the phase observation value deviation of the second frequency point; The determining of the broadcasting satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value deviation, and the phase observation value deviation includes: Determining the visibility of each satellite based on the initial position, and selecting as the broadcasting satellite a satellite that meets the visibility requirements, has a corresponding space signal ranging error correction number within a preset space signal ranging error correction number range, has a corresponding pseudorange observation value deviation within a preset pseudorange observation value deviation range, and has a corresponding phase observation value deviation within a preset phase observation value deviation range; The encoding method of the broadcast satellite's space signal ranging error correction number, pseudorange observation value deviation change, and phase observation value deviation in the server area short message is determined by the following method, including: Determining the coding scale ratio of the space signal ranging error correction, the pseudorange observation value deviation change, and the phase observation value deviation; specifically, determining the coding scale of each correction information based on the impact of the space signal ranging error, the pseudorange observation value deviation change, and the phase observation value deviation coding error on the wide lane and narrow lane ambiguity fixation and the impact on positioning accuracy; Wide lane ambiguity N MW Expressed as: ； Among them, the parameter λ MW =c / (f1-f2), parameter λ NL =c / (f1+f2), where c is the speed of light, P1 is the pseudorange observation value of the first frequency point, P2 is the pseudorange observation value of the second frequency point, L1 is the phase observation value of the first frequency point, and L2 is the phase observation value of the second frequency point; The pseudorange and phase OSBs are directly modified on the pseudorange and phase observations. The ratio of the impact of the coding error of the first-frequency pseudorange observation deviation change, the second-frequency pseudorange observation deviation change, the first-frequency phase observation deviation, and the second-frequency phase observation deviation on the wide-lane ambiguity is: ； The narrow lane ambiguity is expressed as: ； Determining a coding scale of the space signal ranging error correction number based on a coding scale ratio of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation; The coding scales of the pseudorange observation value deviation change and the phase observation value deviation are respectively calculated based on the determined coding scale of the space signal ranging error correction number and the coding scale ratio. The coding data lengths of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation are respectively determined based on the valid ranges of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation.

2. A positioning method based on regional short messages, characterized in that: Applied to the user side, including: Obtaining a regional short message generated by the regional short message encoding method according to claim 1 and sent by the server; Decoding the regional short message to obtain the space signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of each broadcasting satellite; Obtaining a preset initial value of the pseudorange observation value deviation of each of the broadcasting satellites, and adding a change in the pseudorange observation value deviation to the initial value of the pseudorange observation value deviation to obtain the pseudorange observation value deviation of each of the broadcasting satellites; Obtaining a pseudorange observation value and a phase observation value of each of the broadcasting satellites, correcting the corresponding pseudorange observation value by the pseudorange observation value deviation, and correcting the corresponding phase observation value by the phase observation value deviation, to obtain a corrected pseudorange and phase for each of the broadcasting satellites; Based on the corrected pseudorange and phase, the wide lane ambiguity is calculated and fixed by applying the MW combined observation value, and the narrow lane ambiguity is calculated and fixed based on the real-time precise point positioning algorithm; The location coordinates of the user terminal are calculated.

3. A regional short message encoding device, characterized in that: include: A data module is used to determine the initial position of the user terminal based on the regional short message sent by the user terminal, and calculate the space signal ranging error correction number of each satellite based on the initial position; The data module is further configured to determine an initial value of the pseudorange observation deviation of each satellite, and to obtain a change in the pseudorange observation deviation of each satellite by subtracting the pseudorange observation deviation of each satellite from the corresponding initial value of the pseudorange observation deviation; and to obtain a phase observation deviation of each satellite; A satellite selection module is used to determine the broadcast satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value deviation and the phase observation value deviation; A regional short message encoding module is used to generate a server-side regional short message based on the space signal ranging error correction number, the pseudorange observation value deviation change and the phase observation value deviation of the broadcasting satellite; The data length of the short message in the server area is less than a preset short message data length threshold; The server-side regional short message includes a message header, satellite correction information and a CRC check code in sequence; The message header includes a synchronization code, a time identifier, and a satellite identifier in sequence; The satellite correction information includes, in sequence, the ephemeris age of each broadcast satellite, the space signal ranging error correction number of each broadcast satellite, the pseudorange observation value deviation change, and the phase observation value deviation; the total data length of the satellite correction information is 1650 bits, and the data length of each satellite is 55 bits; The satellite identification includes an identification bit of each satellite arranged in a preset order, the identification bit of the broadcasting satellite is 1, and the identification bit of the non-broadcasting satellite is 0; The generating of the server-side regional short message based on the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation of the broadcasting satellite includes: Filling the ephemeris age, space signal ranging error correction number, pseudorange observation value deviation change and phase observation value deviation of the corresponding broadcast satellite into the satellite correction information based on the order of the satellite identifiers; Combining the message header, the satellite correction information, and the CRC check code to generate the server-side regional short message; The broadcast satellite pseudorange observation value deviation variation includes the pseudorange observation value deviation variation of the first frequency point and the pseudorange observation value deviation variation of the second frequency point, and the broadcast satellite phase observation value deviation includes the phase observation value deviation of the first frequency point and the phase observation value deviation of the second frequency point; The determining of the broadcasting satellite based on the visibility of each satellite, the space signal ranging error correction number, the pseudorange observation value deviation, and the phase observation value deviation includes: Determining the visibility of each satellite based on the initial position, and selecting as the broadcasting satellite a satellite that meets the visibility requirements, has a corresponding space signal ranging error correction number within a preset space signal ranging error correction number range, has a corresponding pseudorange observation value deviation within a preset pseudorange observation value deviation range, and has a corresponding phase observation value deviation within a preset phase observation value deviation range; The encoding method of the broadcast satellite's space signal ranging error correction number, pseudorange observation value deviation change, and phase observation value deviation in the server area short message is determined by the following method, including: Determining the coding scale ratio of the space signal ranging error correction, the pseudorange observation value deviation change, and the phase observation value deviation; specifically, determining the coding scale of each correction information based on the impact of the space signal ranging error, the pseudorange observation value deviation change, and the phase observation value deviation coding error on the wide lane and narrow lane ambiguity fixation and the impact on positioning accuracy; Wide lane ambiguity N MW Expressed as: ； Among them, the parameter λ MW =c / (f1-f2), parameter λ NL =c / (f1+f2), where c is the speed of light, P1 is the pseudorange observation value of the first frequency point, P2 is the pseudorange observation value of the second frequency point, L1 is the phase observation value of the first frequency point, and L2 is the phase observation value of the second frequency point; The pseudorange and phase OSBs are directly modified on the pseudorange and phase observations. The ratio of the impact of the coding error of the first-frequency pseudorange observation deviation change, the second-frequency pseudorange observation deviation change, the first-frequency phase observation deviation, and the second-frequency phase observation deviation on the wide-lane ambiguity is: ； The narrow lane ambiguity is expressed as: ； Determining a coding scale of the space signal ranging error correction number based on a coding scale ratio of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation; The coding scales of the pseudorange observation value deviation change and the phase observation value deviation are respectively calculated based on the determined coding scale of the space signal ranging error correction number and the coding scale ratio. The coding data lengths of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation are respectively determined based on the valid ranges of the space signal ranging error correction number, the pseudorange observation value deviation change, and the phase observation value deviation.

4. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the method according to claim 1 or the method according to claim 2 are implemented.

5. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to claim 1 or the method according to claim 2 are implemented.

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