Initialization method and device of GNSS / inertial integrated navigation system

Abstract

The invention relates to the technical field of navigation and positioning, and discloses an initialization method of a GNSS / inertial integrated navigation system. Comprising the following steps: acquiring system information stored at the end of the last work; judging whether the obtained system information is valid or not; after the SINS rapid initialization process is completed, whether a GNSS signal is available or not is judged, and if the GNSS signal is not available, real-time position information, speed information and attitude information are updated; if yes, a GNSS auxiliary positioning process is entered; the calculated position information is used as a constraint, and rapid satellite searching and capturing are carried out; screening the GNSS observed quantity, if the GNSS observed quantity passes the screening, carrying out primary positioning, and if the GNSS observed quantity does not pass the screening, carrying out re-screening; verifying a positioning result of GNSS primary positioning and a current position obtained by inertial navigation calculation, if verification succeeds, entering GNSS / SINS integrated navigation positioning, and if verification fails, entering an SINS reinitialization process; the method has the advantages of instantaneously completing SINS calibration, improving the first positioning accuracy of the GNSS and the like.

Description

Technical Field

[0001] The present invention relates to the field of navigation and positioning technology, and in particular to an initialization method and device for a GNSS / inertial combined navigation system. Background Art

[0002] With the rapid development of satellite navigation technology, the functions of navigation, positioning, timing and communication provided by it have been widely used, and the global satellite navigation and positioning industry as a whole has also shown a rapid growth trend. However, GNSS receivers face many challenges in complex and changing urban environments, such as the obstruction of satellite signals by high-rise buildings and trees, the multipath effect caused by glass curtain walls and water surfaces, and satellite signal blind spots such as tunnels and underground garages. Simply relying on the Global Navigation Satellite System (GNSS) can no longer meet the functional requirements of continuous and precise positioning. The combined navigation technology based on low-cost micro-electro-mechanical system (MEMS) and GNSS has been widely used, but the strapdown inertial navigation system (SINS) composed of MEMS accelerometers and gyroscopes must be initialized and aligned before entering the combined navigation work. The accuracy and time of initialization alignment are important performance indicators for evaluating the combined navigation system.

[0003] The initialization alignment of SINS usually includes the determination of the initial position, initial velocity and initial attitude. Specifically, the initial position and velocity usually rely on the input of external high-precision information, such as the precise position and velocity data analyzed after real-time positioning by the GNSS system. In the calibration of the initial attitude, the process is subdivided into two stages: coarse alignment and fine alignment. In the coarse alignment stage, the system uses the gravity acceleration vector measured by the accelerometer under static conditions and the earth's rotation angular velocity vector measured by the gyroscope to obtain a rough estimate of the initial attitude through an analytical method. In the fine alignment stage, it is based on coarse alignment, cleverly integrating the rich observation data provided by external navigation equipment such as GNSS and the real-time output of MEMS inertial devices, and calibrating the small deviation (i.e., misalignment angle) between the real coordinate system and the calculated navigation coordinate system through algorithms such as Kalman filtering, further improving the accuracy of attitude estimation.

[0004] It can be seen that the efficiency and effect of SINS initialization alignment are largely subject to the performance of the GNSS system. The availability of GNSS signals, the reliability of observation data, and the complexity of the signal environment are all key factors affecting the GNSS measurement accuracy and speed. In the case of limited GNSS signals or harsh environments, such as signal obstruction, significant multipath effects, or no signal coverage at all (such as tunnels, underground parking lots, etc.), the GNSS positioning time will be significantly extended and the positioning accuracy will be greatly reduced. This chain reaction directly leads to a slower SINS initialization alignment process, which in turn affects the startup speed and performance of the entire integrated navigation system, and may ultimately bring users a poor positioning experience.

[0005] In order to improve the adaptability and performance of the integrated navigation system in complex urban environments, it is urgent to solve the problems of the accuracy of the first positioning of the GNSS receiver under signal-limited conditions and the rapid initial alignment of the SINS.

[0006] Therefore, a method and device for initializing a GNSS / inertial integrated navigation system are provided to solve the above problems. Summary of the invention

[0007] The main purpose of the present invention is to solve the problems of the accuracy of the first positioning of a GNSS receiver in a signal-harsh environment and the rapid initial alignment of a SINS in the prior art.

[0008] A first aspect of the present invention provides a method for initializing a GNSS / inertial integrated navigation system, the method for initializing a GNSS / inertial integrated navigation system comprising:

[0009] Get the system information saved at the end of the last work from the storage medium;

[0010] Determine whether the acquired system information is valid; if valid, enter the SINS quick initialization process; if invalid, enter the SINS re-initialization process;

[0011] Enter the SINS fast initialization process, extract the SINS installation angle information in the last system information, and use the last attitude information of the last positioning as the initial attitude information of SINS to complete the SINS fast initialization process;

[0012] Determine whether the GNSS signal is available. If the GNSS signal is not available, update the real-time position information, speed information and attitude information through the strapdown inertial navigation algorithm, and continue to determine the availability of the GNSS signal; if the GNSS signal is available, enter the GNSS assisted positioning process;

[0013] Enter the GNSS assisted positioning process, use the initial position in the system information obtained from the storage medium or the current position information obtained by inertial navigation as a constraint, and use the assisted positioning information, including the historical ephemeris, time information or AGNSS injection information obtained from the storage medium as input to quickly search and capture satellites;

[0014] The GNSS observations are screened based on the above constraint information. If they pass the screening, the GNSS initial positioning is performed. If they fail the screening, the observations are re-screened using the conventional RAIM algorithm.

[0015] The positioning result of the GNSS initial positioning and the current position obtained by inertial navigation are verified. If the verification is successful, the GNSS / SINS integrated navigation positioning is entered. If the verification fails, the SINS re-initialization process is entered.

[0016] Furthermore, the SINS reinitialization process includes:

[0017] The SINS is reinitialized and aligned using the GNSS position, velocity and heading information.

[0018] Further, the rapid satellite search and capture includes:

[0019] Capture a strong signal satellite, use the strong signal satellite as a reference satellite and integrate auxiliary positioning information, including historical ephemeris, time information or AGNSS injection information obtained from the storage medium to calculate other satellite capture parameters;

[0020] Among them, the calculation formula for the launch time of the satellite to be searched is:

[0021]

[0022] in, The launch time of the satellite i to be searched, is the launch time of the reference satellite; are the satellite-to-earth distances of the reference satellite and the satellite i to be searched, and the distance from the satellite to the receiver;

[0023] The Doppler formula of the satellite to be searched is expressed as:

[0024] Doppler = -f i +f clkDrift

[0025] where f i is the frequency shift caused by the movement of the receiver and satellite i; f clkDrift This is the frequency shift caused by the receiver clock drift.

[0026] Furthermore, the screening of GNSS observations based on historical information includes:

[0027] The residual value of the pseudorange is calculated based on the prior information. The specific calculation includes:

[0028] The relationship between the pseudorange observation value ρ and the true distance r from the receiver to the satellite is as follows:

[0029] ρ=r+δt u -δt+δε

[0030] In the formula, δt u is the receiver clock error; δt is the satellite clock error; δε is the atmospheric error and other errors;

[0031] The specific calculation formula of the pseudorange prediction value is:

[0032]

[0033] The satellite position is (x s ,y s ,z s ), the receiver’s prior position is (x r ,y r ,z r ).

[0034] Then, the observations are screened based on the calculated residual values, such as determining the residual threshold through 3 times the mean error or cluster analysis. If the threshold is exceeded, the observation is directly deleted. It should be noted that the number of deleted observations needs to meet the requirements of the satellite configuration. If too many satellites are deleted, the positioning accuracy will also decrease.

[0035] Further, the positioning result of the GNSS initial positioning is verified, if the verification is successful, the GNSS / SINS integrated navigation positioning is entered, if the verification fails, the SINS re-initialization process is entered, including:

[0036] Set a dynamic error threshold based on the SINS working time to judge the comparison between the GNSS initial positioning result and the SINS positioning result; if the difference exceeds the error threshold, the verification fails and enters the SINS reinitialization process; if the difference does not exceed the error threshold, the verification succeeds and enters the GNSS / SINS combined navigation positioning.

[0037] Furthermore, the algorithm model of the combined navigation positioning specifically includes:

[0038] The Kalman filter is used in the integrated navigation algorithm model, and the state vector selects SINS position error, velocity error, attitude error, accelerometer error, gyroscope error, GNSS clock error and clock drift error:

[0039]

[0040] The SINS / GNSS integrated navigation algorithm uses the difference between the position and velocity calculated by SINS and the position and velocity measured by GNSS as measurement information:

[0041] Z=[P INS -P GNSS ,Vel INS -Vel GNSS ].

[0042] The present invention makes full use of the usage characteristics of the device as well as historical positioning and attitude information, which can not only quickly complete the initialization alignment of the integrated navigation system, but also further improve the initial positioning accuracy of the GNSS system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flowchart of a method for initializing a GNSS / inertial integrated navigation system provided by an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the structure of an initialization device for a GNSS / inertial integrated navigation system provided in an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The embodiment of the present invention provides an initialization method for a GNSS / inertial combined navigation system, comprising obtaining system information saved at the end of the last work from a storage medium; judging whether the obtained system information is valid; if valid, entering a SINS fast initialization process; if invalid, entering a SINS reinitialization process; entering the SINS fast initialization process, extracting SINS installation angle information from the last system information, and using the last attitude information of the last positioning as the initial attitude information of the SINS, to complete the SINS fast initialization process; judging whether a GNSS signal is available, if the GNSS signal is not available, updating real-time position information, speed information and attitude information through a strapdown inertial navigation algorithm, and continuously judging the availability of the GNSS signal; if the GNSS signal is available, entering a GNSS assisted positioning process; entering a GNSS assisted The positioning process uses the initial position information in the system information obtained from the storage medium or the current position obtained by inertial navigation as a constraint, and uses auxiliary positioning information, including historical ephemeris, time information or AGNSS injection information obtained from the storage medium as input, to perform rapid satellite search and capture; GNSS observations are screened based on the above constraints, and if they pass the screening, GNSS initial positioning is performed; if they fail the screening, the observations are re-screened using the conventional RAIM algorithm; the positioning result of the GNSS initial positioning is verified, and if the verification is successful, the GNSS / SINS combined navigation positioning is entered, and if the verification fails, the SINS reinitialization process is entered. The main purpose of the present invention is to solve the problems of the accuracy of the first positioning of the GNSS receiver under signal-limited conditions and the fast initial alignment of the SINS in the prior art.

[0047] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] For ease of understanding, the specific process of the embodiment of the present invention is described below. Figure 1-3 , an embodiment of the initialization method of the GNSS / inertial integrated navigation system of the present invention includes:

[0049] Get the system information saved at the end of the last work from the storage medium;

[0050] Determine whether the acquired system information is valid; if valid, enter the SINS quick initialization process; if invalid, enter the SINS re-initialization process;

[0051] Enter the SINS fast initialization process, extract the SINS installation angle information in the last system information, and use the last attitude information of the last positioning as the initial attitude information of SINS to complete the SINS fast initialization process;

[0052] Determine whether the GNSS signal is available. If the GNSS signal is not available, update the real-time position information, speed information and attitude information through the strapdown inertial navigation algorithm, and continue to determine the availability of the GNSS signal; if the GNSS signal is available, enter the GNSS assisted positioning process;

[0053] Enter the GNSS assisted positioning process, use the initial position in the system information obtained from the storage medium or the current position information obtained by inertial navigation as a constraint, and use the assisted positioning information, including the historical ephemeris, time information or AGNSS injection information obtained from the storage medium as input to quickly search and capture satellites;

[0054] Based on the above constraints, the GNSS observations are screened. If they pass the screening, the GNSS initial positioning is performed. If they fail the screening, the observations are re-screened using the conventional RAIM algorithm.

[0055] The positioning result of the GNSS initial positioning and the current position obtained by inertial navigation are verified. If the verification is successful, the GNSS / SINS integrated navigation positioning is entered. If the verification fails, the SINS re-initialization process is entered.

[0056] The SINS reinitialization process includes:

[0057] The SINS is reinitialized and aligned using the GNSS position, velocity and heading information.

[0058] The rapid satellite search and acquisition process includes:

[0059] Capture a strong signal satellite, use the strong signal satellite as a reference satellite and integrate auxiliary positioning information, including historical ephemeris, time information or AGNSS injection information obtained from the storage medium to calculate other satellite capture parameters;

[0060] Among them, the calculation formula for the launch time of the satellite to be searched is:

[0061]

[0062] in, The launch time of the satellite i to be searched, is the launch time of the reference satellite; are the satellite-to-earth distances of the reference satellite and the satellite i to be searched, and the distance from the satellite to the receiver;

[0063] The Doppler formula of the satellite to be searched is expressed as:

[0064] Doppler = -f i +f clkDrift

[0065] where f i is the frequency shift caused by the movement of the receiver and satellite i; f clkDrift This is the frequency shift caused by the receiver clock drift.

[0066] The screening of GNSS observations based on historical information includes:

[0067] The residual value of the pseudorange is calculated based on the prior information. The specific calculation includes:

[0068] The relationship between the pseudorange observation value ρ and the true distance r from the receiver to the satellite is as follows:

[0069] ρ=r+δt u -δt+δε

[0070] In the formula, δt u is the receiver clock error; δt is the satellite clock error; δε is the atmospheric error and other errors; the specific calculation formula for the pseudorange prediction value is:

[0071]

[0072] The satellite position is (x s ,y s ,z s ), the receiver’s prior position is (x r ,y r ,z r ).

[0073] Then, the observations are screened based on the calculated residual values, such as determining the residual threshold through 3 times the mean error or cluster analysis. If the threshold is exceeded, the observation is directly deleted. It should be noted that the number of deleted observations needs to meet the requirements of the satellite configuration. If too many satellites are deleted, the positioning accuracy will also decrease.

[0074] The positioning result of the GNSS initial positioning and the current position obtained by inertial navigation are verified. If the verification is successful, the GNSS / SINS integrated navigation positioning is entered. If the verification fails, the SINS re-initialization process is entered, including:

[0075] Set a dynamic error threshold based on the SINS working time to judge the comparison between the GNSS initial positioning result and the SINS positioning result; if the difference exceeds the error threshold, the verification fails and enters the SINS reinitialization process; if the difference does not exceed the error threshold, the verification succeeds and enters the GNSS / SINS combined navigation positioning.

[0076] The algorithm model of the integrated navigation positioning specifically includes:

[0077] The Kalman filter is used in the integrated navigation algorithm model, and the state vector selects SINS position error, velocity error, attitude error, accelerometer error, gyroscope error, GNSS clock error and clock drift error:

[0078]

[0079] The SINS / GNSS integrated navigation algorithm uses the difference between the position and velocity calculated by SINS and the position and velocity measured by GNSS as measurement information:

[0080] Z=[P INS -P GNSS ,Vel INS -Vel GNSS ].

[0081] The above describes the initialization method of the GNSS / inertial integrated navigation system in the embodiment of the present invention. The following describes the initialization device of the GNSS / inertial integrated navigation system in the embodiment of the present invention. Figure 2 The initialization device of the GNSS / inertial integrated navigation system in the embodiment of the present invention includes:

[0082] The system information acquisition module is used to acquire the system information saved at the end of the last work from the storage medium;

[0083] The first judgment module is used to judge whether the acquired system information is valid; if it is valid, the SINS fast initialization process is entered; if it is invalid, the SINS re-initialization process is entered;

[0084] The fast initialization module is used to enter the SINS fast initialization process, extract the SINS installation angle information in the last system information, and use the last attitude information of the last positioning as the initial attitude information of SINS to complete the SINS fast initialization process;

[0085] The second judgment module is used to judge whether the GNSS signal is available. If the GNSS signal is not available, the real-time position information, speed information and attitude information are updated through the strapdown inertial navigation algorithm, and the availability of the GNSS signal is continuously judged; if the GNSS signal is available, the GNSS assisted positioning process is entered;

[0086] The auxiliary positioning module is used to enter the GNSS auxiliary positioning process, use the initial position information in the system information obtained from the storage medium as a constraint, and use the auxiliary positioning information, including the historical ephemeris, time information or AGNSS injection information obtained from the storage medium as input, to perform rapid satellite search and capture;

[0087] The observation screening module is used to screen the GNSS observations based on historical information. If they pass the screening, the GNSS initial positioning is performed. If they fail the screening, the observations are re-screened.

[0088] The positioning result verification module is used to verify the positioning result of the GNSS initial positioning. If the verification is successful, the GNSS / SINS combined navigation positioning is entered. If the verification fails, the SINS re-initialization process is entered.

[0089] above Figure 2 The initialization device of the GNSS / inertial integrated navigation system in the embodiment of the present invention is described in detail from the perspective of modular functional entities. The electronic device in the embodiment of the present invention is described in detail from the perspective of hardware processing.

[0090] Figure 3 7 is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device 700 may have relatively large differences due to different configurations or performances, and may include one or more processors 710 (for example, one or more processors) and a memory 720, and one or more storage media 730 (for example, one or more storage devices, including RAM\FLASH, etc.) storing application programs 733 or data 732. Among them, the memory 720 and the storage medium 730 may be temporary storage or permanent storage. The program stored in the storage medium 730 may include one or more modules (not shown in the figure), and each module may include a series of instruction operations in the electronic device 700. Furthermore, the processor 710 may be configured to communicate with the storage medium 730 to execute a series of instruction operations in the storage medium 730 on the electronic device 700.

[0091] The electronic device 700 may also include one or more power supplies 740, one or more input / output interfaces 750, and / or one or more operating systems 731, such as FreeRTOS, Android, etc. It will be appreciated by those skilled in the art that Figure 3 The structure of the electronic device shown does not constitute a limitation on the electronic device, and may include more or less components than shown in the figure, or combine some components, or arrange the components differently.

[0092] The present invention also provides a computer-readable storage medium, which may be a non-volatile computer-readable storage medium or a volatile computer-readable storage medium. The computer-readable storage medium stores instructions, which, when executed on a computer, enable the computer to execute the steps of a method for initializing a GNSS / inertial combined navigation system.

[0093] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system, device, or unit can refer to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0094] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, mobile device, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program codes.

[0095] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. 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 invention.

Claims

1. A method for initializing a GNSS / inertial integrated navigation system, characterized in that: The initialization method of the GNSS / inertial integrated navigation system includes: Get the system information saved at the end of the last work from the storage medium; Determine whether the acquired system information is valid; if valid, enter the SINS quick initialization process; if invalid, enter the SINS re-initialization process; Enter the SINS fast initialization process, extract the SINS installation angle information in the last system information, and use the last attitude information of the last positioning as the initial attitude information of SINS to complete the SINS fast initialization process; Determine whether the GNSS signal is available. If the GNSS signal is not available, update the real-time position information, speed information and attitude information through the strapdown inertial navigation algorithm, and continue to determine the availability of the GNSS signal; if the GNSS signal is available, enter the GNSS assisted positioning process; Enter the GNSS assisted positioning process, use the initial position information in the system information obtained from the storage medium or the current position obtained by inertial navigation as a constraint, and use the assisted positioning information, including the historical ephemeris, time information or AGNSS injection information obtained from the storage medium as input to perform rapid satellite search and capture; The GNSS observations are screened based on the above constraint information. If they pass the screening, the GNSS initial positioning is performed. If they fail the screening, the observations are re-screened using the conventional RAIM algorithm. The positioning result of the GNSS initial positioning and the current position obtained by inertial navigation are verified. If the verification is successful, the GNSS / SINS integrated navigation positioning is entered. If the verification fails, the SINS re-initialization process is entered.

2. The method for initializing a GNSS / inertial integrated navigation system according to claim 1, characterized in that: The SINS reinitialization process includes: The SINS is re-initialized and aligned using the GNSS position information, velocity information, and heading information.

3. The method for initializing a GNSS / inertial integrated navigation system according to claim 1, characterized in that: The rapid satellite search and acquisition process includes: Capture a strong signal satellite, use the strong signal satellite as a reference satellite and integrate auxiliary positioning information, including historical ephemeris, time information or AGNSS injection information obtained from the storage medium, to calculate other satellite capture parameters; Among them, the calculation formula for the launch time of the satellite to be searched is: in, The launch time of the satellite i to be searched, is the launch time of the reference satellite; are the satellite-to-earth distances of the reference satellite and the satellite i to be searched, and the distance from the satellite to the receiver; The Doppler formula of the satellite to be searched is expressed as: Doppler=-f i +f clkDrift where f i is the frequency shift caused by the movement of the receiver and satellite i; f clkDrift This is the frequency shift caused by the receiver clock drift.

4. The method for initializing a GNSS / inertial integrated navigation system according to claim 1, characterized in that: The screening of GNSS observations based on historical information includes: The residual value of the pseudorange is calculated based on the prior information. The specific calculation includes: The relationship between the pseudorange observation value ρ and the true distance r from the receiver to the satellite is as follows: ρ=r+δt u -δt+δe In the formula, δt u is the receiver clock error; δt is the satellite clock error; δε is the atmospheric error and other errors; The specific calculation formula of the pseudorange prediction value is: The satellite position is (x s ,y s ,z s ), the receiver’s prior position is (x r ,y r ,z r ). The screening of observations is performed based on the calculated residual values.

5. The method for initializing a GNSS / inertial integrated navigation system according to claim 1, characterized in that: The process of verifying the positioning result of the GNSS initial positioning and the current position obtained by inertial navigation calculation, and entering the GNSS / SINS integrated navigation positioning if the verification succeeds, and entering the SINS re-initialization process if the verification fails includes: Set a dynamic error threshold based on the SINS working time to judge the comparison between the GNSS initial positioning result and the SINS positioning result; if the difference exceeds the error threshold, the verification fails and enters the SINS reinitialization process; if the difference does not exceed the error threshold, the verification succeeds and enters the GNSS / SINS combined navigation positioning.

6. The method for initializing a GNSS / inertial integrated navigation system according to claim 1, characterized in that: The algorithm model of the integrated navigation positioning specifically includes: The Kalman filter is used in the integrated navigation algorithm model, and the state vector selects SINS position error, velocity error, attitude error, accelerometer error, gyroscope error, GNSS clock error and clock drift error: The SINS / GNSS integrated navigation algorithm uses the difference between the position and velocity calculated by SINS and the position and velocity measured by GNSS as measurement information: Z=[P INS -P GNSS ,Vel INS -Vel GNSS ]。 7. An initialization device for a GNSS / inertial integrated navigation system, characterized in that: include: The system information acquisition module is used to acquire the system information saved at the end of the last work from the storage medium; The first judgment module is used to judge whether the acquired system information is valid; if it is valid, the SINS fast initialization process is entered; If invalid, enter the SINS reinitialization process; The fast initialization module is used to enter the SINS fast initialization process, extract the SINS installation angle information in the last system information, and use the last attitude information of the last positioning as the initial attitude information of SINS to complete the SINS fast initialization process; The second judgment module is used to judge whether the GNSS signal is available. If the GNSS signal is not available, the real-time position information, speed information and attitude information are updated through the strapdown inertial navigation algorithm, and the availability of the GNSS signal is continuously judged; If the GNSS signal is available, the GNSS assisted positioning process will be entered; The auxiliary positioning module is used to enter the GNSS auxiliary positioning process, use the initial position information in the system information obtained from the storage medium or the current position obtained by inertial navigation as a constraint, and use the auxiliary positioning information, including the historical ephemeris, time information or AGNSS injection information obtained from the storage medium as input, to perform rapid satellite search and capture; The observation screening module is used to screen the GNSS observations based on historical information. If they pass the screening, the GNSS initial positioning is performed. If they fail the screening, the conventional RAIM algorithm is used to re-screen the observations. The positioning result verification module is used to verify the positioning result of the GNSS initial positioning. If the verification is successful, the GNSS / SINS combined navigation positioning is entered. If the verification fails, the SINS re-initialization process is entered.

8. An electronic device, comprising a memory and at least one processor, wherein the memory stores instructions and data; The at least one processor calls the instructions and data in the memory to enable the electronic device to perform each step of the initialization method of the GNSS / inertial combined navigation system according to any one of claims 1-6.

9. A readable storage medium having instructions and data stored thereon, characterized in that: When the instruction is executed by the processor, the various steps of the initialization method of the GNSS / inertial combined navigation system as claimed in any one of claims 1 to 6 are implemented; the data at least includes the system information saved at the end of the last work, which serves as the input information for the initialization of the GNSS / inertial combined navigation system.

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