Cross-latitude navigation drift error compensation method and system

Abstract

The invention discloses a cross-latitude navigation drift error compensation method and system, and the method comprises the steps: collecting navigation original data through a multi-sensor system, carrying out the filtering and fusion processing, dividing a latitude interval according to the latitude information, and carrying out the filtering and fusion processing; main sources and characteristics of navigation drift errors in different intervals are analyzed, an error model is established, compensation values of the navigation drift errors in different latitude intervals are calculated according to the error model, mutual influence of various error sources is comprehensively considered, the compensation values are applied to a navigation system, and the compensation effect is compared with a reference navigation system to evaluate the compensation effect. If the preset precision requirement is not met, the result is fed back to the error characteristic analysis and modeling step to optimize the error model.According to the method, the accurate error model is established by deeply analyzing the error characteristics of different latitude areas, and a comprehensive compensation strategy is adopted, so that the navigation drift error is effectively reduced, and the navigation precision and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the field of navigation technology, and in particular to a cross-latitude navigation drift error compensation method and system. Background Art

[0002] In the field of modern navigation technology, the Global Navigation Satellite System (GNSS) plays an extremely critical role, such as the widely used Global Positioning System (GPS) and BeiDou Satellite Navigation System. However, when the navigation mission involves cross-latitude areas, the navigation system often suffers from drift errors due to the complex physical properties of the earth itself and the diversity of the navigation environment.

[0003] The earth is not an ideal sphere, but an ellipsoid that is slightly flat at the poles and slightly bulging at the equator. This non-spherical shape causes differences in the propagation paths and geometric relationships of satellite signals in different latitudes, which in turn leads to positioning errors. At the same time, the distribution of satellite orbits does not evenly cover all latitudes around the world. The coverage angle and signal strength of satellite signals in high-latitude areas will vary relative to those in low-latitude areas, which has a significant impact on navigation accuracy.

[0004] In addition, the signal propagation environment in different latitudes is completely different. In low-latitude areas, ionospheric activity is more active, and ionospheric delay becomes one of the main sources of error. The free electrons in the ionosphere will refract and delay satellite signals, causing deviations in the signal propagation time received by the navigation system, resulting in inaccurate positioning. Moreover, the multipath effect is more significant in low-latitude areas. During the propagation process, the signal is reflected by buildings, water surfaces, etc. before reaching the receiving antenna, interfering with the directly transmitted signal, further increasing the error.

[0005] In mid-latitudes, the Coriolis force caused by the rotation of the Earth begins to have a greater impact on navigation. The Coriolis force will cause the trajectory of moving objects to shift. For high-speed navigation carriers, such as airplanes and high-speed trains, this shift will gradually accumulate, causing the deviation between the position calculated by the navigation system and the actual position to become larger and larger. At the same time, the change in the inclination angle of the satellite orbit in mid-latitudes will also affect the reception quality and geometric relationship of the satellite signal, thereby introducing errors.

[0006] High-latitude regions face unique challenges. Changes in the Earth's magnetic field interfere with navigation signals. Changes in the magnetic field affect the measurement accuracy of sensors such as magnetometers, which in turn causes deviations in the navigation system's judgment of direction. In addition, the polar region's ionosphere has a special structure. The irregularities of the polar ionosphere and the dramatic changes in plasma density cause complex errors in satellite signals when they propagate in this region.

[0007] Most existing navigation error compensation methods have limitations. Some methods only correct a single error source, such as simply dealing with ionospheric delay or only considering the multipath effect, while ignoring the combined impact of other factors at different latitudes. Some methods are only applicable to specific local areas or specific navigation scenarios, and lack comprehensive adaptability to cross-latitude long-distance navigation. This lack of systematic and comprehensive error compensation mechanism makes it difficult to meet the stringent requirements of today's high-precision navigation in cross-latitude applications. There is an urgent need for a new method and system that can comprehensively and effectively compensate for cross-latitude navigation drift errors. Summary of the invention

[0008] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0009] Therefore, the purpose of the present invention is to provide a cross-latitude navigation drift error compensation method and system, which can effectively reduce the navigation drift error and improve the navigation accuracy and reliability by deeply analyzing the error characteristics of different latitude regions, establishing an accurate error model, and adopting a comprehensive compensation strategy.

[0010] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0011] A cross-latitude navigation drift error compensation method, the steps are as follows:

[0012] S1. Data acquisition and preprocessing: Collect raw navigation data through a multi-sensor system and perform filtering and fusion processing;

[0013] S2. Error characteristic analysis and modeling: Divide the latitude intervals according to the latitude information, analyze the main sources and characteristics of navigation drift errors in different intervals and establish error models;

[0014] S3, error compensation calculation: calculate the compensation value of navigation drift error in different latitude intervals based on the error model and comprehensively consider the mutual influence of multiple error sources;

[0015] S4. Evaluation and feedback of compensation effect: The compensation value is applied to the navigation system and compared with the reference navigation system to evaluate the compensation effect. If the predetermined accuracy requirement is not met, the compensation effect is fed back to the error characteristic analysis and modeling step to optimize the error model.

[0016] As a preferred solution of the cross-latitude navigation drift error compensation method described in the present invention, the multi-sensor system includes a satellite navigation receiver, an inertial measurement unit and a magnetometer;

[0017] The satellite navigation receiver acquires satellite signals, including the satellite's position information and signal propagation time, to determine the initial position and velocity estimate of the navigation vehicle;

[0018] The inertial measurement unit measures the acceleration and angular velocity information of the navigation carrier;

[0019] Magnetometers measure information about the strength of the Earth's magnetic field.

[0020] As a preferred solution of the cross-latitude navigation drift error compensation method of the present invention, in step S2, the specific steps of dividing the latitude intervals according to the latitude information, analyzing the main sources and characteristics of the navigation drift errors in different intervals and establishing the error model are as follows:

[0021] In low-latitude areas, the main error sources include ionospheric delay and satellite signal multipath effect. The Klobuchar model is used to preliminarily describe the ionospheric delay error in low-latitude areas and is corrected in combination with the local geographical environment and meteorological data.

[0022] In mid-latitudes, the Coriolis force caused by the rotation of the earth affects navigation accuracy. At the same time, the change in the inclination angle of the satellite orbit causes errors. For the Coriolis force error in mid-latitudes, a mathematical model based on the angular velocity of the earth's rotation and the speed of the navigation carrier is established;

[0023] In high-latitude areas, changes in the Earth's magnetic field and the special ionosphere structure in the polar regions cause large deviations in navigation signals. For the magnetic field interference errors in high-latitude areas, the magnetometer measurement data is used to establish an error model related to the changes in magnetic field intensity.

[0024] As a preferred solution of the cross-latitude navigation drift error compensation method described in the present invention, in step S3, the specific steps of calculating the compensation value of the navigation drift error in different latitude intervals according to the error model and comprehensively considering the mutual influence of multiple error sources are as follows:

[0025] When calculating the total compensation value in low-latitude areas, the compensation for ionospheric delay and the correction value of the satellite signal multipath effect are comprehensively considered. The integral error correction algorithm is used to compensate for the cumulative error of the inertial measurement unit. The integral errors of acceleration and angular velocity are corrected in real time according to the motion state and time information of the navigation carrier. At the same time, the magnetometer data is used to compensate for the directional deviation caused by magnetic field interference to ensure the accuracy of the navigation direction.

[0026] As a preferred solution of the cross-latitude navigation drift error compensation method described in the present invention, in step S4, the compensation value is applied to the navigation system, and the compensation effect is evaluated by comparing with the reference navigation system. If the predetermined accuracy requirement is not met, the error characteristic analysis and modeling step is fed back to optimize the error model. The specific steps are as follows:

[0027] By comparing with high-precision navigation systems such as ground reference stations, the compensation effect is evaluated, and the root mean square of the position error and the root mean square of the velocity error navigation error indicators after compensation are calculated. If the compensation effect does not meet the predetermined accuracy requirements, the evaluation results are fed back to the error characteristic analysis and modeling steps, the error model is optimized and adjusted, and the compensation value is recalculated until a satisfactory compensation effect is achieved.

[0028] As a preferred solution of the cross-latitude navigation drift error compensation method described in the present invention, in step S2, the divided latitude intervals include low latitude 0°-30°, mid-latitude 30°-60° and high latitude 60°-90° intervals.

[0029] A cross-latitude navigation drift error compensation system, comprising:

[0030] A data acquisition module, used to collect raw navigation data through a multi-sensor system;

[0031] The data preprocessing module is used to filter the collected raw data and fuse the satellite navigation data and inertial measurement data;

[0032] Error analysis and modeling module, used to divide latitude intervals according to latitude information and establish models of navigation drift errors in different intervals;

[0033] An error compensation calculation module is used to calculate the compensation value based on the error model and comprehensively consider the mutual influence of multiple error sources;

[0034] The compensation effect evaluation and feedback module is used to apply the compensation value to the navigation system and compare it with the reference navigation system to evaluate the compensation effect. If the predetermined accuracy requirement is not met, the compensation effect is fed back to the error analysis and modeling module to optimize the error model.

[0035] As a preferred solution of the cross-latitude navigation drift error compensation system described in the present invention, the data preprocessing module uses a Kalman filter algorithm to fuse the satellite navigation data and the inertial measurement data.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The present invention can calculate the compensation value in a targeted manner and effectively reduce the navigation position, speed and direction errors caused by various factors by accurately analyzing and modeling the error sources in different latitudes, such as ionospheric delay, multipath effect and satellite geometric distribution in low latitudes, Coriolis force and satellite orbit inclination angle changes in mid-latitudes, magnetic field interference in high latitudes and special structure of polar ionosphere, etc. For example, in low-latitude areas, the improved Klobuchar model is used in combination with a variety of environmental data to correct the ionospheric delay, and the multipath effect and satellite geometric distribution are comprehensively considered, which can greatly reduce the root mean square of the position error from several meters or even more than ten meters before compensation to within several meters, greatly improving the positioning accuracy of navigation in low-latitude areas.

[0038] 2. The multi-sensor system (satellite navigation receiver, inertial measurement unit and magnetometer) in the data acquisition module cooperates with each other and undergoes data preprocessing and fusion. Even if the satellite signal is temporarily lost or interfered with, the inertial measurement unit can still provide relatively accurate navigation information in a short period of time, and the magnetometer can assist in correcting the direction deviation caused by changes in the magnetic field. The system can maintain a certain navigation capability and accuracy, reduce the risk of navigation failure due to single sensor failure or environmental interference, and improve the stability and continuity of navigation.

[0039] 3. The compensation effect evaluation and feedback mechanism can monitor navigation errors in real time. Once it is found that the compensation effect does not meet the requirements, the error model will be optimized and adjusted in time to ensure that the system is always in a good working condition and continuously provide reliable navigation results, effectively reducing the impact of navigation error accumulation on long-distance navigation tasks and ensuring the safety and accuracy of the entire navigation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below in combination with the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0041] Figure 1 The present invention is a flow chart of a cross-latitude navigation drift error compensation method. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0043] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0044] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] The present invention provides a cross-latitude navigation drift error compensation method and system, which establishes an accurate error model by deeply analyzing the error characteristics of different latitude areas and adopts a comprehensive compensation strategy to effectively reduce the navigation drift error and improve the navigation accuracy and reliability.

[0046] like Figure 1 As shown, a cross-latitude navigation drift error compensation method, the steps are as follows:

[0047] S1. Data acquisition and preprocessing: The navigation raw data is collected through a multi-sensor system and filtered and fused. Specifically, the multi-sensor system includes a satellite navigation receiver, an inertial measurement unit and a magnetometer. The satellite navigation receiver obtains satellite signals including the satellite position information and signal propagation time to determine the initial position and velocity estimate of the navigation carrier. The inertial measurement unit measures the acceleration and angular velocity information of the navigation carrier. The magnetometer measures the earth's magnetic field strength information.

[0048] S2. Error characteristic analysis and modeling: Latitude intervals are divided according to latitude information, and the main sources and characteristics of navigation drift errors in different intervals are analyzed and error models are established. Specifically, the divided latitude intervals include low latitudes 0°-30°, mid-latitudes 30°-60° and high latitudes 60°-90°. In low latitudes, the main error sources include ionospheric delay and satellite signal multipath effect. For the ionospheric delay error in low latitudes, the Klobuchar model is used for preliminary description and corrected in combination with the local geographical environment and meteorological data. In mid-latitudes, the Coriolis force caused by the rotation of the earth affects the navigation accuracy, and the change in the inclination angle of the satellite orbit causes errors. For the Coriolis force error in mid-latitudes, a mathematical model based on the angular velocity of the earth's rotation and the speed of the navigation carrier is established. In high latitudes, changes in the earth's magnetic field and the special ionospheric structure in the polar regions cause large deviations in the navigation signal. For the magnetic field interference error in high latitudes, the magnetometer measurement data is used to establish an error model related to the change in magnetic field intensity.

[0049] S3. Error compensation calculation: The compensation value of navigation drift error in different latitude intervals is calculated based on the error model and the mutual influence of various error sources is comprehensively considered. Specifically, when calculating the total compensation value in low-latitude areas, the compensation of ionospheric delay and the correction value of satellite signal multipath effect are comprehensively considered. For the accumulated error of the inertial measurement unit, the integral error correction algorithm is used for compensation. According to the motion state and time information of the navigation carrier, the integral error of acceleration and angular velocity is corrected in real time. At the same time, the magnetometer data is used to compensate for the direction deviation caused by magnetic field interference to ensure the accuracy of the navigation direction.

[0050] S4. Evaluation and feedback of compensation effect: Apply the compensation value to the navigation system and compare it with the reference navigation system to evaluate the compensation effect. If the predetermined accuracy requirement is not met, the compensation result will be fed back to the error characteristic analysis and modeling step to optimize the error model. Specifically, the compensation effect is evaluated by comparing it with a high-precision navigation system such as a ground reference station, and the compensated position error root mean square and velocity error root mean square navigation error indicators are calculated. If the compensation effect does not meet the predetermined accuracy requirement, the evaluation result will be fed back to the error characteristic analysis and modeling step to optimize and adjust the error model and recalculate the compensation value until a satisfactory compensation effect is achieved.

[0051] A cross-latitude navigation drift error compensation system includes a data acquisition module, a data preprocessing module, an error analysis and modeling module, an error compensation calculation module and a compensation effect evaluation and feedback module, wherein the data acquisition module is used to collect raw navigation data through a multi-sensor system;

[0052] The data preprocessing module is used to filter the collected raw data and fuse the satellite navigation data and inertial measurement data;

[0053] The error analysis and modeling module is used to divide the latitude intervals according to the latitude information and establish the model of navigation drift error in different intervals;

[0054] The error compensation calculation module is used to calculate the compensation value based on the error model and comprehensively consider the mutual influence of multiple error sources;

[0055] The compensation effect evaluation and feedback module is used to apply the compensation value to the navigation system and compare it with the reference navigation system to evaluate the compensation effect. If the predetermined accuracy requirement is not met, it is fed back to the error analysis and modeling module to optimize the error model.

[0056] In order to verify the technical effects of the cross-latitude navigation drift error compensation method and system of the present invention, the following embodiments 1-2 and experimental examples 1-2 are provided.

[0057] Example 1: Low-latitude marine navigation application

[0058] A merchant ship sailing in low-latitude waters (such as 5°N-25°N) has its navigation system adopt the cross-latitude navigation drift error compensation method and system of the present invention.

[0059] The satellite navigation receiver in the multi-source data acquisition module continuously receives GPS and Beidou satellite signals, the inertial measurement unit measures the acceleration and angular velocity of the merchant ship in real time, and the magnetometer measures the strength of the earth's magnetic field. The data preprocessing module uses the adaptive Kalman filter algorithm to fuse the satellite navigation data and inertial measurement data, remove noise and outliers, and obtain a more accurate initial navigation state estimate.

[0060] The error analysis and modeling module determines that ionospheric delay, multipath effect and satellite geometric distribution are the main error sources according to the low-latitude interval where the merchant ship is located. The improved Klobuchar model is used to establish a low-latitude error model in combination with local solar activity monitoring data, meteorological data and satellite geometric distribution. For example, at a certain moment, the preliminary compensation value of ionospheric delay is calculated based on the local sunspot activity intensity and ionospheric electron density distribution forecast. At the same time, by analyzing the reflection characteristics of the sea surface around the merchant ship, the influence of the multipath effect is determined and the corresponding compensation value is calculated.

[0061] The error compensation calculation module calculates the error compensation value based on the low-latitude error model. First, the compensation values ​​of ionospheric delay and multipath effect are substituted into the satellite navigation positioning algorithm to recalculate the position and speed of the merchant ship. Then, based on the recalculated results, the impact of satellite geometric distribution on positioning accuracy is evaluated, the satellite geometric precision factor is dynamically adjusted, and the compensation value is calculated again. After multiple iterative calculations, the optimal error compensation value is obtained.

[0062] The compensation effect monitoring and feedback module compares the compensated navigation data with the navigation data of the nearby coastal reference station. In the early stage of navigation, when no compensation is performed, the position error RMS is about 10 meters, and the speed error RMS is about 0.8 meters per second. After the error compensation of the present invention, the position error RMS is reduced to less than 3 meters, and the speed error RMS is reduced to less than 0.2 meters per second. During the navigation process, if bad weather or a brief interruption of the satellite signal occurs, resulting in a decrease in the compensation effect, the compensation effect monitoring and feedback module will promptly feed back the evaluation results to the error analysis and modeling module. For example, when encountering a strong tropical storm, the ionospheric activity is abnormally intense. The error analysis and modeling module will readjust the parameters in the improved Klobuchar model based on the feedback information, and recalculate the compensation value to ensure that the navigation accuracy always remains at a high level.

[0063] Example 2: Mid-latitude aviation flight navigation application

[0064] A civil airliner flying in a mid-latitude region (such as 35°N-55°N) adopts the navigation compensation system of the present invention.

[0065] The satellite navigation receiver in the multi-source data acquisition module receives GPS and Galileo satellite signals, the inertial measurement unit accurately measures the acceleration and angular velocity of the aircraft, and the magnetometer monitors the strength of the earth's magnetic field. After the data preprocessing module fuses the collected data, the error analysis and modeling module determines that the Coriolis force and the change in the satellite orbit inclination angle are the main error sources.

[0066] According to the aircraft's flight speed, latitude and the earth's rotation angular velocity, the Coriolis force error model is used to calculate the impact of the Coriolis force on aircraft navigation. At the same time, according to the satellite orbit parameters and the aircraft's position, the satellite orbit inclination error model is used to calculate the error caused by the change in the satellite orbit inclination angle. The compensation values ​​calculated by these two error models are applied to the data processing of the inertial measurement unit and the satellite navigation positioning calculation to correct the aircraft's acceleration, angular velocity, satellite signal propagation time and other parameters.

[0067] The error compensation calculation module gradually reduces the navigation error in mid-latitude areas through multiple iterations of optimization. For example, in a long-distance flight, before compensation, the position error RMS was about 15 meters, and the speed error RMS was about 1 meter per second. After the error compensation of the present invention, the position error RMS is stabilized within 5 meters, and the speed error RMS is reduced to about 0.3 meters per second. During the flight, if the aircraft changes its route or flight altitude, causing the satellite geometry to change, the compensation effect monitoring and feedback module will promptly detect the change in compensation effect and feed back the relevant information to the error analysis and modeling module. The error analysis and modeling module will adjust the relevant parameters in the satellite orbit inclination angle error model according to the new situation, recalculate the compensation value, and ensure that the navigation accuracy is not affected by changes in route and altitude.

[0068] Example 3: High-latitude polar scientific research navigation application

[0069] A vehicle carrying out scientific research missions in polar regions (such as 70°N-85°N) has its navigation system using the cross-latitude navigation drift error compensation method and system of the present invention.

[0070] The satellite navigation receiver in the multi-source data acquisition module receives Beidou and GLONASS satellite signals, the inertial measurement unit measures the acceleration and angular velocity of the vehicle, and the magnetometer measures the strength of the earth's magnetic field. After the data preprocessing module processes the data, the error analysis and modeling module establishes an error model for the drastic changes in the earth's magnetic field and the special structure of the polar ionosphere.

[0071] The magnetic field interference error model is used to calculate the deviation compensation value of the navigation direction according to the magnetic field strength and direction changes measured by the magnetometer. At the same time, the error correction method based on the polar ionosphere physical model is used to calculate the compensation value of the polar ionosphere error by considering the complex physical processes such as plasma density inhomogeneity, plasma convection and magnetosphere-ionosphere coupling in the polar ionosphere. These two compensation values ​​are applied to the navigation system to jointly correct the magnetometer measurement data and satellite navigation data.

[0072] In order to fully verify the effectiveness of the cross-latitude navigation drift error compensation method and system of the present invention, a series of experiments were conducted.

[0073] Experimental Example 1: Cross-latitude long-distance navigation experiment.

[0074] Experimental equipment: A mobile test platform equipped with the navigation compensation system of the present invention, including a high-precision satellite navigation receiver, an inertial measurement unit, a magnetometer, and a data recording and processing unit.

[0075] Experimental route: Starting from the low latitude area (15°S), passing through the mid-latitude area (45°N), and finally reaching the high latitude area (75°N), the total journey is about 10,000 kilometers.

[0076] Experimental process: During the entire navigation process, the original navigation data and the compensated navigation data are recorded at regular intervals (e.g., 10 seconds). After the experiment, the collected data are analyzed in detail.

[0077] Experimental results: When the compensation system of the present invention is not used, the navigation position error increases significantly with time and latitude, the average position error RMS for the entire process reaches 20 meters, and the maximum position error exceeds 50 meters. After using the compensation system of the present invention, the average position error RMS for the entire process is reduced to 6 meters, and the maximum position error is controlled within 15 meters. In terms of speed error, the average speed error RMS is 1 meter / second when not compensated, and it is reduced to 0.3 meters / second after compensation. The direction error fluctuates greatly during the cross-latitude process when not compensated, and the maximum deviation angle reaches 5°. After compensation, the direction deviation angle is basically controlled within 1°.

[0078] Experimental Example 2: Comparative experiments under different environments.

[0079] Experimental setup: Navigation experiments were conducted in urban environment, mountain environment and marine environment respectively, and each environment was equipped with an uncompensated control group and an experimental group using the compensation system of the present invention.

[0080] Experimental data: In urban environments, the average RMS position error is 12 meters without compensation, and it is reduced to 4 meters after using the compensation system; in mountainous environments, the average RMS position error is 15 meters without compensation, and it is 5 meters after compensation; in marine environments, the average RMS position error is 8 meters without compensation, and it is 3 meters after compensation. The speed error and direction error have also been significantly improved in different environments, and the error indicators of the experimental group are significantly better than those of the control group.

[0081] It can be seen from the above experiments that the cross-latitude navigation drift error compensation method and system of the present invention can effectively reduce the navigation drift error in different latitude areas and different environments, significantly improve the accuracy and reliability of navigation, and meet the needs of cross-latitude navigation for high-precision navigation in various application scenarios.

[0082] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A cross-latitude navigation drift error compensation method, characterized in that: Here are the steps: S1. Data acquisition and preprocessing: Collect raw navigation data through a multi-sensor system and perform filtering and fusion processing; S2. Error characteristic analysis and modeling: Divide the latitude intervals according to the latitude information, analyze the main sources and characteristics of navigation drift errors in different intervals and establish error models; S3, error compensation calculation: calculate the compensation value of navigation drift error in different latitude intervals based on the error model and comprehensively consider the mutual influence of multiple error sources; S4. Evaluation and feedback of compensation effect: The compensation value is applied to the navigation system and compared with the reference navigation system to evaluate the compensation effect. If the predetermined accuracy requirement is not met, the compensation effect is fed back to the error characteristic analysis and modeling step to optimize the error model.

2. A cross-latitude navigation drift error compensation method according to claim 1, characterized in that: The multi-sensor system includes a satellite navigation receiver, an inertial measurement unit and a magnetometer; The satellite navigation receiver acquires satellite signals, including the satellite's position information and signal propagation time, to determine the initial position and velocity estimate of the navigation vehicle; The inertial measurement unit measures the acceleration and angular velocity information of the navigation carrier; Magnetometers measure information about the strength of the Earth's magnetic field.

3. The cross-latitude navigation drift error compensation method according to claim 1, characterized in that: In step S2, the specific steps of dividing the latitude intervals according to the latitude information, analyzing the main sources and characteristics of the navigation drift errors in different intervals and establishing the error model are as follows: In low-latitude areas, the main error sources include ionospheric delay and satellite signal multipath effect. The Klobuchar model is used to preliminarily describe the ionospheric delay error in low-latitude areas and is corrected in combination with the local geographical environment and meteorological data. In mid-latitudes, the Coriolis force caused by the rotation of the earth affects navigation accuracy. At the same time, the change in the inclination angle of the satellite orbit causes errors. For the Coriolis force error in mid-latitudes, a mathematical model based on the angular velocity of the earth's rotation and the speed of the navigation carrier is established; In high-latitude areas, changes in the Earth's magnetic field and the special ionosphere structure in the polar regions cause large deviations in navigation signals. For the magnetic field interference errors in high-latitude areas, the magnetometer measurement data is used to establish an error model related to the changes in magnetic field intensity.

4. The cross-latitude navigation drift error compensation method according to claim 1, characterized in that: In step S3, the specific steps of calculating the compensation value of the navigation drift error in different latitude intervals according to the error model and comprehensively considering the mutual influence of multiple error sources are as follows: When calculating the total compensation value in low-latitude areas, the compensation for ionospheric delay and the correction value of the satellite signal multipath effect are comprehensively considered. The integral error correction algorithm is used to compensate for the cumulative error of the inertial measurement unit. The integral errors of acceleration and angular velocity are corrected in real time according to the motion state and time information of the navigation carrier. At the same time, the magnetometer data is used to compensate for the directional deviation caused by magnetic field interference to ensure the accuracy of the navigation direction.

5. The cross-latitude navigation drift error compensation method according to claim 1, characterized in that: In step S4, the compensation value is applied to the navigation system and compared with the reference navigation system to evaluate the compensation effect. If the predetermined accuracy requirement is not met, it is fed back to the error characteristic analysis and modeling step to optimize the error model. The specific steps are as follows: By comparing with high-precision navigation systems such as ground reference stations, the compensation effect is evaluated, and the root mean square of the position error and the root mean square of the velocity error navigation error indicators after compensation are calculated. If the compensation effect does not meet the predetermined accuracy requirements, the evaluation results are fed back to the error characteristic analysis and modeling steps, the error model is optimized and adjusted, and the compensation value is recalculated until a satisfactory compensation effect is achieved.

6. The cross-latitude navigation drift error compensation method according to claim 1, characterized in that: In step S2, the divided latitude intervals include low latitude 0°-30°, mid latitude 30°-60° and high latitude 60°-90° intervals.

7. A system for implementing a cross-latitude navigation drift error compensation method as claimed in any one of claims 1 to 6, characterized in that: include: A data acquisition module, used to collect raw navigation data through a multi-sensor system; The data preprocessing module is used to filter the collected raw data and fuse the satellite navigation data and inertial measurement data; Error analysis and modeling module, used to divide latitude intervals according to latitude information and establish models of navigation drift errors in different intervals; An error compensation calculation module is used to calculate the compensation value based on the error model and comprehensively consider the mutual influence of multiple error sources; The compensation effect evaluation and feedback module is used to apply the compensation value to the navigation system and compare it with the reference navigation system to evaluate the compensation effect. If the predetermined accuracy requirement is not met, the compensation effect is fed back to the error analysis and modeling module to optimize the error model.

8. The cross-latitude navigation drift error compensation system according to claim 7, characterized in that: The data preprocessing module uses a Kalman filter algorithm to perform fusion processing on satellite navigation data and inertial measurement data.

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