A geophysical field matching navigation adaptability pre-analysis and real-time correction method

Abstract

The present disclosure provides a geophysical field matching navigation adaptability pre-analysis and real-time correction method, which comprises: 1) pre-analysis stage: estimating a first inertial navigation error according to estimated navigation information and inertial navigation parameters; determining the size of a pre-analysis search window according to the first inertial navigation error; performing adaptability analysis in the pre-analysis search window, and performing flight path planning and navigation reference according to the adaptability analysis result; 2) actual navigation stage: estimating a second inertial navigation error according to real-time navigation information and inertial navigation parameters; determining the size of a real-time correction search window according to the second inertial navigation error; performing adaptability analysis in the real-time correction search window; and performing real-time matching navigation at a matching point with adaptability meeting the requirement according to the current adaptability analysis result. The present application can improve the accuracy of adaptability analysis and adaptability area selection, adapt to the requirements of flight path planning and maneuvering navigation, and improve the matching efficiency.

Description

Technical Field

[0001] This invention relates to the field of navigation, guidance and control technology, and specifically to a method for pre-analysis and real-time correction of navigation adaptability in geophysical field matching. Background Technology

[0002] Navigation technology is one of the key technologies for sea, land, and air navigation. It directly determines whether a vehicle can navigate safely and accurately reach its designated operational location, and is a crucial factor in determining the success or failure of a mission.

[0003] Inertial navigation is an autonomous, closed, all-weather navigation system capable of high-precision navigation over short periods, making it one of the most important navigation methods. However, due to the characteristics of its sensors and the influence of its navigation algorithms, errors in inertial sensors accumulate during the navigation calculation process, leading to a continuous decrease in accuracy. Therefore, when using inertial navigation systems for long-endurance navigation, it is necessary to use other navigation sensors or systems for calibration.

[0004] Geophysical field matching navigation can be divided into terrain matching navigation, gravity matching navigation and geomagnetic matching navigation according to different geophysical parameters. The basic principle of all of them is to compare the geophysical field background map that is accurately obtained in advance in the vehicle with the geophysical field characteristics of the vehicle's location that are continuously measured by sensors, so as to obtain the vehicle's position.

[0005] Because the richness of geophysical field characteristics varies across different regions, it is necessary to analyze suitable matching regions using existing geophysical field data. Traditional adaptability analysis often fails to consider the impact of inertial navigation error characteristics and flight status (track, velocity, attitude, etc.) on adaptability, resulting in inaccurate selection of the adaptation zone. Furthermore, traditional methods do not correct the results of the adaptability analysis based on real-time flight status. When the real-time flight status differs significantly from the preset flight status, the original analysis results may become inapplicable. Therefore, traditional methods are not well-suited for maneuvering navigation. Summary of the Invention

[0006] In view of this, the present invention provides a geophysical field matching navigation adaptability pre-analysis and real-time correction method, which can improve the accuracy of adaptability analysis and adaptability zone selection, while adapting to two different needs of trajectory planning and maneuvering navigation, and improving matching efficiency.

[0007] To solve the above-mentioned technical problems, the present invention is implemented as follows.

[0008] A method for pre-analysis and real-time correction of geophysical field matching navigation adaptability, the method comprising:

[0009] Pre-analysis phase: Estimate the first inertial navigation error based on the predicted navigation information and inertial navigation parameters; determine the size of the pre-analysis search window based on the first inertial navigation error; perform adaptability analysis within the pre-analysis search window; and perform trajectory planning and navigation reference based on the adaptability analysis results.

[0010] During the actual navigation phase: the second inertial navigation error is estimated based on real-time navigation information and inertial navigation parameters; the size of the real-time correction search window is determined based on the second inertial navigation error; adaptability analysis is performed within the real-time correction search window; and real-time matching navigation is performed at matching points where the adaptability requirements are met, based on the current adaptability analysis results.

[0011] Preferably, in the pre-analysis stage, the first inertial navigation error is estimated based on different predicted navigation information and inertial navigation parameters, and adaptability analysis is performed to obtain different adaptation zones. The adaptation zone used in actual navigation is selected according to mission requirements. The selected adaptation zone is used for trajectory planning and navigation reference.

[0012] Preferably, during the pre-analysis stage, when determining the pre-analysis search window, for cases where the inertial navigation device is fixed to the carrier, the navigation trajectory is segmented and straightened.

[0013] For the straight segment, neglecting linear velocity and linear acceleration, the inertial navigation error of the straight segment is estimated using the inertial navigation error formula under static base conditions. When entering the next trajectory segment, the angular motion of the carrier is equivalent to the change in the projection of the gyroscope constant drift and the accelerometer zero bias in the navigation coordinate system. Then, the error equation of the inertial navigation system is equal to the error equation of the previous straight segment plus the error terms generated by the change in gyroscope drift and the change in accelerometer zero bias in the input navigation coordinate system at the trajectory transition point.

[0014] When analyzing the adaptability of a point P, the first inertial navigation error is determined based on the error equation of the line segment where point P is located, and then the size of the pre-analysis search window is determined. The adaptability analysis of point P is then performed using the pre-analysis search window.

[0015] Preferably, in the pre-analysis stage, the segmentation method is as follows:

[0016] Case 1: When the trajectory is a straight line, retain the original trajectory;

[0017] Case 2: When dealing with a curved trajectory, divide the curve into segments such that the angle between the line connecting the two ends of each segment and any tangent line of that segment is less than or equal to the threshold Agl. thres Replace the curve segment with the line connecting the two endpoints;

[0018] Case 3: When dealing with a broken line trajectory, the trajectory is divided into multiple straight lines by using the turning point as the trajectory dividing point;

[0019] Case 4: During uniform circular motion for an entire full circle, (1) if the angular frequency of the motion is greater than twice the Schuler frequency ω s Then only the error caused by the gyroscope constant drift and the projection of the accelerometer zero bias onto the straight line of the central axis of the circular motion is considered, and the projection of the gyroscope constant drift and the accelerometer zero bias onto the plane of the circular motion is ignored; (2) if the angular frequency of motion is less than or equal to 2 times ω s Handle according to situation 2;

[0020] Case 5: Non-uniform or non-full-circle motion, handled as in case 2.

[0021] Preferably, during the actual navigation phase, when determining the search window, for cases where the inertial navigation device is fixed to the carrier, the navigation trajectory is segmented and straightened.

[0022] For the straight segment, neglecting linear velocity and linear acceleration, the inertial navigation error of the straight segment is estimated using the inertial navigation error formula under static base conditions. When entering the next trajectory segment, the angular motion of the carrier is equivalent to the change in the projection of the gyroscope constant drift and the accelerometer zero bias in the navigation coordinate system. Then, the error equation of the inertial navigation system is equal to the error equation of the previous straight segment plus the error terms generated by the change in gyroscope drift and the change in accelerometer zero bias in the input navigation coordinate system at the trajectory transition point.

[0023] When analyzing the adaptability of a point P, the second inertial navigation error is determined based on the error equation of the line segment where point P is located, and then the size of the real-time correction search window is determined. The adaptability analysis of point P is then performed using the real-time correction search window.

[0024] Preferably, during the actual navigation phase, the segmentation method is as follows:

[0025] Take a piecewise time interval T that is much smaller than the Schuler period cor The actual navigation trajectory is segmented; the segmentation time interval T cor The value range is 10-20 minutes; for each segment, the average gyroscope constant drift and the average accelerometer zero bias in the navigation coordinate system are used to replace the gyroscope constant drift and accelerometer zero bias in the corresponding direction of the straight line segment. This is equivalent to fixing the attitude on the straight line segment, that is, approximating the curved trajectory as multiple straight line trajectories.

[0026] Preferably, during the pre-analysis phase and the actual navigation phase, the size of the search window is determined based on the inertial navigation error as follows:

[0027] Based on inertial navigation error, a fault tolerance space is combined as a search window for adaptability analysis;

[0028] set up Let δλ be the point to be analyzed. p Let p be the estimated inertial navigation longitude error. Let p be the estimated latitude error of inertial navigation at point p; then,

[0029] p-point search window S ear The length of the longitude direction is: after adding 1 point of redundancy to the left and right of the absolute value of the longitude error of the inertial navigation, the whole number is rounded up.

[0030] p-point search window S ear The latitudinal length is: the absolute value of the inertial navigation latitude error is rounded up to the nearest whole number.

[0031] Preferably, the method further includes: during the actual navigation phase, when the difference between the estimated navigation information and the actual navigation information corresponding to the current adaptation zone exceeds a set range, performing a new adaptation analysis and correcting the adaptation zone in real time; the difference includes any one or more of the following: speed, time, position, and attitude.

[0032] The adaptation analysis was re-performed as follows:

[0033] The first step is to obtain the segmented results of the actual navigation trajectory from the starting point to the current position;

[0034] The second step is to use the current position as the starting point and employ the pre-analysis method to obtain the trajectory segmentation results from the current position to the target position.

[0035] The third step is to connect the two sets of trajectories obtained in the first and second steps in sequence to obtain a complete set of trajectories.

[0036] The fourth step is to estimate the inertial navigation error based on the trajectory set and inertial navigation parameters.

[0037] Step 5: Based on the inertial navigation error estimated in step 4, determine the real-time correction search window and obtain the corrected adaptation area.

[0038] Preferably, the geophysical field is a gravity field, and the inertial navigation system is a strapdown inertial navigation system.

[0039] Preferably, the navigation information includes track, speed, time, and attitude.

[0040] Beneficial effects:

[0041] (1) This invention designs two stages: adaptability pre-analysis and real-time correction, which can provide support for both trajectory planning and real-time navigation. The real-time correction scheme is more adaptable to maneuvering navigation that does not follow the original plan. When the adaptability changes due to the vehicle not following the original trajectory, speed, time, attitude, etc., the real-time matching can be unaffected because of the real-time adaptation correction.

[0042] (2) The window for adaptability analysis in this invention is obtained based on inertial navigation error, rather than using a set value. On the one hand, this avoids interference caused by an excessively large search window, and on the other hand, it avoids failure to cover the real location due to an excessively small search window.

[0043] (3) The present invention designs a segmented linearization scheme for the predicted trajectory, analyzes the characteristics of different types of trajectories and designs a linearization scheme, simplifies the inertial navigation error analysis of motion state, and enables the inertial navigation error study under static base conditions to be applied to motion state, while ensuring accuracy.

[0044] (4) A segmented straightening scheme for real-time trajectory was designed. This scheme is not constrained by the trajectory shape, can be calculated in real time, and can better adapt to the maneuvering of the aircraft.

[0045] (5) Since the trajectory is segmented and straightened, this invention can provide an analytical approximate solution for the strapdown inertial navigation error of any shape trajectory, avoiding the huge amount of computation required by the numerical iteration method, which is faster and more conducive to adaptability analysis.

[0046] (6) Since the window for adaptability analysis is determined based on the divergence of the inertial navigation system and a fault tolerance space is set, the present invention can avoid interference caused by inaccurate window scale and analyze adaptability more accurately.

[0047] (7) Because the present invention can analyze adaptability more accurately, it can select the adaptation area more efficiently. Attached Figure Description

[0048] Figure 1 This is a flowchart illustrating a geophysical field matching navigation adaptability pre-analysis and real-time correction method provided by the present invention. Detailed Implementation

[0049] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] Given that underwater gravity matching navigation has high stealth capabilities and is an important passive underwater navigation method, and that gravity field information is stable, this invention mainly describes underwater gravity matching navigation in its embodiments. However, it is also applicable to other geophysical field matching navigation methods such as terrain matching navigation and geomagnetic matching navigation, and is also applicable to non-underwater scenarios such as land and air.

[0051] This invention provides a geophysical field matching navigation adaptability pre-analysis and real-time correction method, which uses a strapdown inertial navigation system as the inertial navigation system. Based on mission requirements, it is divided into the following two stages:

[0052] (1) Adaptability Pre-analysis Stage

[0053] Step 1: Select the target point and the expected flight path. Its advantage is that it analyzes the adaptability from the perspective of the whole system. Adaptability is not only related to the geophysical field background map, but also to the flight path, inertial navigation performance, and flight speed, etc., which can analyze the adaptability more accurately.

[0054] Step 2: Segment the predicted trajectory into straight lines.

[0055] This step approximates the trajectory as a piecewise straight line. Its advantage lies in the fact that, after segmentation, the inertial navigation error of each segment can be estimated using the inertial navigation error formula under static base conditions, allowing the study of inertial navigation error under static base conditions to be applied to motion states. Furthermore, the characteristics of different types of trajectories are analyzed and a straightening scheme is designed, simplifying the solution for inertial navigation error in motion states while maintaining accuracy.

[0056] The specific segmentation method is as follows:

[0057] 1) For straight-line trajectories, simply retain the original trajectory.

[0058] 2) For the curve trajectory, divide the curve into segments such that the angle between the line connecting the two ends of each curve segment and any tangent line of that curve segment is less than or equal to the threshold Agl. thres Replace the curve segment with the line connecting the two endpoints.

[0059] 3) Divide the zigzag trajectory into multiple straight lines by using the turning point as the trajectory dividing point.

[0060] 4) For a uniform circular motion trajectory (full circle), if the angular frequency of the motion is greater than twice ω... s (Schuler frequency), then only the errors caused by the gyroscope constant drift and the projection of the accelerometer zero bias onto the straight line of the central axis of the circular motion are considered, and the projection of the gyroscope constant drift and the accelerometer zero bias onto the plane of the circular motion can be ignored; if the angular frequency of motion is less than or equal to 2 times ω s Processed according to the curve trajectory.

[0061] 5) For non-uniform or non-full-circular motion trajectories, treat them as curved trajectories.

[0062] Step 3: Based on the predicted navigation information after segmentation, and in conjunction with the inertial navigation parameters, estimate the inertial navigation error for each segment.

[0063] The navigation information includes trajectory, speed, time, attitude, etc.

[0064] This step can be implemented using a formula-based method. For each straight segment, neglecting linear velocity and linear acceleration, the inertial navigation error after segmenting and straightening the trajectory is estimated using the inertial navigation error formula under static base conditions. When entering the next trajectory segment, the angular motion of the carrier can be equivalent to the change in the projection of the gyroscope constant drift and accelerometer zero bias in the navigation coordinate system. At this time, the error equation of the inertial navigation system is equal to the original error equation plus the error terms generated by the changes in gyroscope drift and accelerometer zero bias in the input navigation coordinate system at the trajectory transition point. Therefore, when analyzing the fit for a certain point P, the inertial navigation error is determined according to the error equation of the straight segment where point P is located. Its advantage is that it can provide an analytical approximate solution for the inertial navigation error of trajectories with arbitrary shapes, avoiding the huge amount of computation required by numerical iteration methods, and is fast.

[0065] Without loss of generality, assume the overall starting point of the voyage is p. start , Let λ be the point to be analyzed. p Let p be the longitude value. Let p be the latitude value of point p. start The time elapsed until p is t p The preset segmented tracks are s1, s2, ..., s n (p is located at s) n (End point), from p start The times to the start of each flight path are t1 (t1 is zero), t2, ..., t n The longitude error δλ corresponding to point p p and latitude error The error equations are as follows:

[0066] δλ p =A λ (t p -t1)Drif1+A λ (t p -t2)(Drif2-Drif1)+…+A λ (t p -t n (Drif) n -Drif n-1 )

[0067]

[0068] Among them, A λ This represents the time-varying coefficient matrix of the inertial navigation longitude error equation under static base conditions. The time-varying coefficient matrix represents the inertial navigation latitude error equation under static base conditions; Drif1 represents the gyroscope constant drift and accelerometer zero bias corresponding to trajectory s1; A λ (t p-t1)Drif1 represents the inertial device drift of the input system at time t1 (t1 value is zero) under static base conditions. p Longitude error caused by time; Drif n -Drif n-1 Indicates the trajectory s n-1 Enter trajectory s n At that time, the change in inertial device drift in the navigation system due to attitude changes; A λ (t p -t n (Drif) n -Drif n-1 ) indicates that under static base conditions, t n Time (i.e., time determined by trajectory s) n-1 Enter trajectory s n (Time) Input system navigation system inertial device drift change Drif n -Drif n-1 In t p Longitude error caused by time of day; Indicates t under static base conditions n Drif, the constant input system's navigation frame inertial device drift change. n -Drif n-1 In t p The latitude error caused by the time; the meaning of other terms in the formula can be deduced in the same way.

[0069] In practice, inertial navigation errors can also be estimated using numerical iteration methods.

[0070] Step 4: Determine the size of the search window based on the inertial navigation error.

[0071] In this step, the inertial navigation error is combined with a tolerance space as the search window for the adaptability analysis. This combination can be achieved by adding the tolerance space to the inertial navigation error and multiplying it by a tolerance coefficient, or by pre-determining a function relating the inertial navigation error to the search window size.

[0072] In this embodiment, an inertial navigation error plus a tolerance space is used: considering that the inertial navigation error of an underwater vehicle is generally no more than 2 points, and the longitude error diverges over time, while the resolution of the gravity anomaly background map is generally 1 or 2 points, the longitude error is rounded up (by point) after adding 1 point of redundancy, and the latitude error is directly rounded up (by point) as the window scale for adaptability analysis.

[0073] set up Let δλ be the target point to be analyzed. p Let p be the estimated inertial navigation longitude error. This represents the estimated inertial navigation latitude error at point p. The window for the adaptability analysis is S. ear ,have

[0074]

[0075] Here, ceil is the floor function. Its advantage lies in the fact that, due to the window S of the fit analysis... ear It is determined based on the degree of divergence of inertial navigation and has a fault tolerance margin, which can avoid interference caused by inaccurate window size and can analyze adaptability more accurately.

[0076] Step 5, in S ear Perform fitness analysis within the range to obtain the fitness of point p. The advantages are the same as in step four.

[0077] Step 6: Repeat steps 1 to 5 to obtain the fit of multiple points.

[0078] In practice, the first inertial navigation error can be estimated based on different predicted navigation information and inertial navigation parameters, and adaptability analysis can be performed to obtain the adaptability of multiple trajectories. Its advantage is that it can not only compare the adaptability differences between different points, but also compare the adaptability differences between different trajectories at the same point.

[0079] After obtaining the adaptability of multiple trajectories, the appropriate adaptation zone for actual navigation can be selected based on mission requirements; then, step seven can be executed using the selected adaptation zone.

[0080] Step 7: Referring to the adaptability analysis results in Step 6, trajectory planning and navigation reference can be performed. Its advantage is that the adaptability pre-analysis results are only used for trajectory planning and navigation reference, not for real-time matching. When the vehicle deviates from its original trajectory, speed, time, attitude, etc., causing changes in adaptability, real-time matching remains unaffected.

[0081] (2) Real-time adaptation correction stage

[0082] Step 1: Inertial navigation outputs real-time position, attitude, and velocity information. Its advantage is that the vehicle can navigate freely, without following the pre-analyzed trajectory, velocity, and attitude.

[0083] Step 2: Select a segmented time interval T that is much smaller than the Schuler period. cor (A duration of 10-20 minutes is acceptable). The gyroscope constant drift and accelerometer zero bias under the navigation system are averaged to replace the device drift during this period. This is equivalent to fixing the attitude on this straight segment, that is, approximating the curved trajectory as a multi-segment straight trajectory. Its advantage is that it designs a segmented straightening scheme based on the error characteristics of strapdown inertial navigation, which is not constrained by the trajectory shape, can better adapt to the maneuvering of the aircraft, and can perform real-time calculations.

[0084] Step 3: Based on the real-time navigation information after segmentation and inertial navigation parameters, estimate the inertial navigation error of each segment.

[0085] The navigation information includes trajectory, speed, time, attitude, etc.

[0086] This step can be implemented using a formula-based method. For each straight segment, neglecting linear velocity and linear acceleration, the inertial navigation error after segmenting and straightening the trajectory is estimated using the inertial navigation error formula under static base conditions. When entering the next trajectory segment, the angular motion of the carrier can be equivalent to the change in the projection of the gyroscope constant drift and accelerometer zero bias in the navigation coordinate system. At this point, the error equation of the inertial navigation system equals the original error equation plus the error terms generated by the changes in gyroscope drift and accelerometer zero bias in the input navigation coordinate system at the trajectory transition point. Its advantage is that it can provide an analytical approximate solution for the inertial navigation error of trajectories with arbitrary shapes, avoiding the huge computational load required by numerical iteration methods, and is faster.

[0087] The error equations during real-time correction are in the same form as those in the pre-analysis stage. The difference lies in the fact that the trajectory, velocity (time), and attitude may differ during real-time correction compared to the pre-analysis stage, and the trajectory segmentation method in step two is also different.

[0088] In practice, inertial navigation errors can also be estimated using numerical iteration methods.

[0089] Step 4: Determine the size of the search window based on the inertial navigation error.

[0090] In this step, the inertial navigation error is combined with a tolerance space as the search window for the adaptability analysis. This combination can be achieved by adding the tolerance space to the inertial navigation error and multiplying it by a tolerance coefficient, or by pre-determining a function relating the inertial navigation error to the search window size.

[0091] In this embodiment, an inertial navigation error plus a tolerance space is used: considering that the inertial navigation error of an underwater vehicle is generally no more than 2 points, and the longitude error diverges over time, while the resolution of the gravity anomaly background map is generally 1 or 2 points, the longitude error is rounded up (by point) after adding 1 point of redundancy, and the latitude error is directly rounded up (by point) as the window scale for adaptability analysis.

[0092] set up Let δλ be the target point to be analyzed. p Let p be the estimated inertial navigation longitude error. This represents the estimated inertial navigation latitude error at point p. The window for the adaptability analysis is S. ear ,have

[0093]

[0094] Here, ceil is the floor function. Its advantage lies in the fact that, due to the window S of the fit analysis... ear It is determined based on the degree of divergence of inertial navigation and has a fault tolerance margin, which can avoid interference caused by inaccurate window size and can analyze adaptability more accurately.

[0095] Step 5, in S ear Perform fitness analysis within the range to obtain the fitness of point p. The advantages are the same as in step four.

[0096] Step Six: Referring to the results of Step Five, real-time matching can be performed in areas where the compatibility requirements are met. Its advantage is that real-time matching only needs to consider the compatibility of real-time corrections; the vehicle can maneuver without worrying about deviations from its original trajectory, speed, time, or attitude.

[0097] Step 7: Repeat steps 1 through 6.

[0098] The method further includes: during the actual navigation phase, if the difference between the estimated navigation information and the actual navigation information corresponding to the current adaptation zone exceeds a set range, it is necessary to re-perform the adaptation analysis and correct the adaptation zone in real time; the difference includes any one or more combinations of speed, time, position, and attitude. The inertial navigation error formula indicates that to estimate the positioning error of the inertial navigation system at a certain moment, not only the navigation information at that moment but also the navigation information from historical moments are needed. Therefore, when re-performing the adaptation analysis, firstly, the trajectory segmentation results of the actual navigation from the starting point to the current position are obtained; secondly, using the current position as the starting point, the trajectory segmentation results from the current position to the target position are obtained using the pre-analysis method; thirdly, the above two sets of trajectories are arranged sequentially to obtain a complete trajectory group; fourthly, the estimated inertial navigation error is obtained according to the formula; finally, based on the estimated inertial navigation error, adaptation analysis is performed within the corresponding window to obtain the corrected adaptation zone.

[0099] In determining the search window, this invention can use a platform inertial navigation system instead of a strapdown inertial navigation system. The orientation of the inertial devices in the platform inertial navigation system is approximately constant, and its error characteristics are similar to those of the strapdown inertial navigation system during straight-line navigation, so segmentation is not required.

[0100] The specific embodiments described above only illustrate the design principles of the present invention. The shapes and names of the components in this description may differ and are not limited. Therefore, those skilled in the art can modify or make equivalent substitutions to the technical solutions described in the foregoing embodiments; and these modifications and substitutions do not depart from the inventive spirit and technical solutions of the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A method for pre-analysis and real-time correction of geophysical field matching navigation adaptability, characterized in that, The method includes: Pre-analysis phase: Estimate the first inertial navigation error based on the predicted navigation information and inertial navigation parameters; use the tolerance space as the size of the pre-analysis search window based on the first inertial navigation error; perform adaptability analysis within the pre-analysis search window; and perform trajectory planning and navigation reference based on the adaptability analysis results. In the actual navigation phase: the second inertial navigation error is estimated based on real-time navigation information and inertial navigation parameters; the size of the real-time correction search window is determined by combining the second inertial navigation error with the fault tolerance space; adaptability analysis is performed within the real-time correction search window; and real-time matching navigation is performed at matching points that meet the adaptability requirements based on the current adaptability analysis results. During the actual navigation phase, if the difference between the estimated navigation information corresponding to the current adaptation zone obtained from the adaptation analysis and the actual navigation information exceeds a set range, the adaptation analysis is re-performed to correct the adaptation zone in real time; the difference includes any one or more of the following: speed, time, position, and attitude.

2. The geophysical field matching navigation adaptability pre-analysis and real-time correction method as described in claim 1, characterized in that, In the pre-analysis phase, the first inertial navigation error is estimated based on different predicted navigation information and inertial navigation parameters, and adaptability analysis is performed to obtain different adaptation zones. The adaptation zone used in actual navigation is selected according to mission requirements. The selected adaptation zone is used for trajectory planning and navigation reference.

3. The geophysical field matching navigation adaptability pre-analysis and real-time correction method as described in claim 1, characterized in that, During the pre-analysis phase, when determining the pre-analysis search window, for cases where the inertial navigation devices are fixed to the carrier, the navigation trajectory is segmented and straightened. For the straight segment, neglecting linear velocity and linear acceleration, the inertial navigation error of the straight segment is estimated using the inertial navigation error formula under static base conditions. When entering the next trajectory segment, the angular motion of the carrier is equivalent to the change in the projection of the gyroscope constant drift and the accelerometer zero bias in the navigation coordinate system. Then, the error equation of the inertial navigation system is equal to the error equation of the previous straight segment plus the error terms generated by the change in gyroscope drift and the change in accelerometer zero bias in the input navigation coordinate system at the trajectory transition point. When analyzing the adaptability of a point P, the first inertial navigation error is determined based on the error equation of the line segment where point P is located, and then the size of the pre-analysis search window is determined. The adaptability analysis of point P is then performed using the pre-analysis search window.

4. The geophysical field matching navigation adaptability pre-analysis and real-time correction method as described in claim 3, characterized in that, In the pre-analysis phase, the segmentation method is as follows: Case 1: When the trajectory is a straight line, retain the original trajectory; Case 2: When dealing with a curved trajectory, the curve is segmented such that the angle between the line connecting the two ends of each segment and any tangent line of that segment is less than or equal to a threshold. Replace the curve segment with the line connecting the two endpoints; Case 3: When dealing with a broken line trajectory, the trajectory is divided into multiple straight lines by using the turning point as the trajectory dividing point; Case 4: During uniform circular motion for an entire full circle, (1) if the angular frequency of the motion is greater than twice the Schuler frequency Then only the error caused by the gyroscope constant drift and the projection of the accelerometer zero bias onto the straight line of the central axis of the circular motion is considered, and the gyroscope constant drift and the projection of the accelerometer zero bias onto the plane of the circular motion are ignored; (2) if the angular frequency of motion is less than or equal to 2 times Handle according to situation 2; Case 5: Non-uniform or non-full-circle motion, handled as in case 2.

5. The geophysical field matching navigation adaptability pre-analysis and real-time correction method as described in claim 1, characterized in that, During the actual navigation phase, when determining the search window, for cases where the inertial navigation devices are fixed to the carrier, the navigation trajectory is segmented and straightened. For the straight segment, neglecting linear velocity and linear acceleration, the inertial navigation error of the straight segment is estimated using the inertial navigation error formula under static base conditions. When entering the next trajectory segment, the angular motion of the carrier is equivalent to the change in the projection of the gyroscope constant drift and the accelerometer zero bias in the navigation coordinate system. Then, the error equation of the inertial navigation system is equal to the error equation of the previous straight segment plus the error terms generated by the change in gyroscope drift and the change in accelerometer zero bias in the input navigation coordinate system at the trajectory transition point. When analyzing the adaptability of a point P, the second inertial navigation error is determined based on the error equation of the line segment where point P is located, and then the size of the real-time correction search window is determined. The adaptability analysis of point P is then performed using the real-time correction search window.

6. The geophysical field matching navigation adaptability pre-analysis and real-time correction method as described in claim 5, characterized in that, During the actual navigation phase, the segmentation method is as follows: Take a segmented time interval much smaller than the Schuler period The actual navigation trajectory is segmented; the time interval between segments is... The value range is 10-20 minutes; For each segment, the average gyroscope constant drift and the average accelerometer zero bias in the navigation coordinate system are used to replace the gyroscope constant drift and accelerometer zero bias in the corresponding direction of the straight line segment. This is equivalent to fixing the attitude on the straight line segment, that is, approximating the curved trajectory as multiple straight line trajectories.

7. The geophysical field matching navigation adaptability pre-analysis and real-time correction method as described in claim 1, characterized in that, In the pre-analysis and actual navigation phases, the size of the search window is determined based on the inertial navigation error and the fault tolerance space as follows: set up ( , () represents the point to be analyzed. for Estimated inertial navigation longitude error at the point. for The estimated latitude error of inertial navigation at point ; then, Click the search window The length of the longitude direction is: after adding 1 point of redundancy to the left and right of the absolute value of the longitude error of the inertial navigation, the whole number is rounded up. Click the search window The latitudinal length is: the absolute value of the inertial navigation latitude error is rounded up to the nearest whole number.

8. The method for pre-analysis and real-time correction of geophysical field matching navigation adaptability as described in claim 1, characterized in that, The re-adaptability analysis is as follows: The first step is to obtain the segmented results of the actual navigation trajectory from the starting point to the current position; The second step is to use the current position as the starting point and employ the pre-analysis method to obtain the trajectory segmentation results from the current position to the target position. The third step is to connect the two sets of trajectories obtained in the first and second steps in sequence to obtain a complete set of trajectories. The fourth step is to estimate the inertial navigation error based on the trajectory set and inertial navigation parameters. Step 5: Based on the inertial navigation error estimated in step 4, determine the real-time correction search window and obtain the corrected adaptation area.

9. A method for pre-analysis and real-time correction of geophysical field matching navigation adaptability as described in any one of claims 1-8, characterized in that, The geophysical field is a gravity field, and the inertial navigation system is a strapdown inertial navigation system.

10. The geophysical field matching navigation adaptability pre-analysis and real-time correction method as described in claim 1, characterized in that, The navigation information includes track, speed, time, and attitude.

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