Inertial navigation position correction method and device based on geomagnetic bionic navigation

Abstract

The invention discloses an inertial navigation position correction method and device based on geomagnetic bionic navigation. According to the invention, by using the positions and geomagnetic information of a plurality of geomagnetic reference points measured in advance, when the underwater vehicle travels to the near sea area near the geomagnetic reference points, the underwater vehicle is driven to move along the direction of the geomagnetic reference points under the guidance of the minimum difference between the geomagnetic information measured in real time and the geomagnetic information of the geomagnetic reference points; the inertial navigation position information is corrected. The method does not need to construct a high-resolution and high-precision terrain / geomagnetism / gravity map, and is easy to implement.

Description

Technical Field

[0001] The present invention relates to the field of underwater navigation technology, and in particular to an inertial navigation position correction method and device based on geomagnetic bionic navigation. Background Art

[0002] The inertial navigation system has the advantages of independence, complete navigation information, and strong concealment. It is the main means for underwater submersibles to provide autonomous navigation information guarantee. However, in principle, the inertial navigation system has the technical characteristics of error divergence over time, and the system performance will continue to decline over time. Therefore, after a period of use, the underwater submersible must surface to obtain accurate position information from satellite navigation to correct the inertial navigation error, which seriously restricts the efficiency of the underwater submersible's operational tasks.

[0003] In order to achieve long-term, high-precision autonomous navigation of underwater submersibles, it is necessary to equip them with underwater precise auxiliary positioning means, and use external high-precision position information to compensate for the errors of the inertial navigation system, mainly including underwater acoustic positioning and geophysical field navigation. However, the use of underwater acoustic positioning has prerequisites and has great safety hazards; geophysical field navigation requires a priori database and has harsh conditions for use. Therefore, it is urgent to develop a safe, reliable, and independent auxiliary navigation means that does not rely on a priori database. Summary of the invention

[0004] In view of this, the present invention provides an inertial navigation position correction method and device based on geomagnetic bionic navigation. By utilizing individual geomagnetic reference points measured in advance and geomagnetic information measured in real time by an underwater submersible, the inertial navigation position correction of the underwater submersible can be effectively realized, which can be applied and promoted in the field of underwater navigation.

[0005] The inertial navigation position correction method based on geomagnetic bionic navigation of the present invention comprises:

[0006] Step 1, setting a number of underwater geomagnetic reference points, and obtaining the position information and geomagnetic characteristic quantity information of the geomagnetic reference points;

[0007] Step 2, during the driving process, the underwater submersible calculates the difference between the position information measured by the inertial navigation and the stored position information of the geomagnetic reference point. If the difference is less than a set threshold, it is determined that the submersible has moved to the sea area near the geomagnetic reference point, and step 3 is executed;

[0008] Step 3, the underwater submersible measures the three-dimensional geomagnetic field strength of the current position in real time; with the goal of minimizing the difference in the three-dimensional geomagnetic field strength between the current position and the geomagnetic reference point, the movement direction of the underwater submersible at the next moment is calculated, and the difference between the actual movement direction and the target heading is used as the feedback input of the heading drive control to perform navigation control on the underwater submersible, driving the underwater submersible to approach the direction of the geomagnetic reference point; when the intensity difference approaches 0, it is determined that the vehicle has reached the geomagnetic reference point; the geomagnetic reference point position replaces the inertial navigation position information to realize the inertial navigation position correction.

[0009] Preferably, in step 1, the magnetic sensor and the satellite navigation antenna are placed on the same wooden base, and are towed by a surface ship to measure the position information and geomagnetic characteristic quantity information of the geomagnetic reference point;

[0010] In step 3, the underwater submersible releases the magnetic sensor and uses a dragging method to measure the geomagnetic information of the current position in real time.

[0011] Preferably, in step 3, the underwater submersible target heading H0 is calculated based on the underwater submersible position information measured in real time by inertial navigation and the stored geomagnetic reference point position information:

[0012]

[0013] Among them, R n Represents the radius of curvature of the Earth's meridian, R e represents the radius of curvature of the earth's circumplex, Δx represents the eastward position difference, and Δy represents the northward position difference;

[0014] Taking the minimum difference in the three-dimensional geomagnetic field intensity between the current position of the underwater vehicle and the position of the geomagnetic reference point as the constraint condition, the movement direction of the underwater vehicle at the next moment is obtained:

[0015] H k+1 =minf(B k ) (9)

[0016] in, is the three-dimensional geomagnetic field strength at the underwater submersible position measured in real time; (B x , B y , B z ) is the three-dimensional geomagnetic field intensity at the geomagnetic reference point;

[0017] The difference between the actual movement direction of the underwater submersible and the target heading is used as the feedback input of the heading drive control, and the underwater submersible is navigated and controlled to drive the underwater submersible to approach the direction of the geomagnetic reference point.

[0018] The present invention also provides an inertial navigation position correction device using the above method, comprising: a magnetic sensor, a storage unit, a real-time calculation unit and a motion control unit;

[0019] Among them, the magnetic sensor is used to measure the geomagnetic information of the current location;

[0020] The storage unit is used to store the location information of the geomagnetic reference point and the geomagnetic characteristic quantity information;

[0021] The real-time calculation unit is used to calculate the difference between the position information measured by the inertial navigation and the position information of the geomagnetic reference point stored in the storage unit, and when the difference is less than a set threshold, the motion control unit is turned on;

[0022] The motion control unit performs navigation control with the goal of minimizing the difference between the geomagnetic information of the current position measured by the magnetic sensor and the geomagnetic information of the geomagnetic reference point stored in the storage unit until the underwater submersible reaches the geomagnetic reference point; the inertial navigation position information is replaced by the position information of the geomagnetic reference point to complete the correction of the inertial navigation position of the underwater submersible.

[0023] Beneficial effects:

[0024] (1) The present invention only requires the measurement of several geomagnetic reference points in advance, and does not require the construction of high-resolution and high-precision topographic / geomagnetic / gravity maps, and has strong operability;

[0025] (2) The present invention adopts the dragging method to measure geomagnetic information, which can effectively avoid the influence of geomagnetic characteristic quantity measurement error (magnetic interference);

[0026] (3) The present invention has strong versatility and can be extended to other carriers. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0029] The present invention provides an inertial navigation position correction method and device based on geomagnetic bionic navigation, which uses individual geomagnetic reference points measured in advance and geomagnetic information measured in real time by an underwater submersible to drive the underwater submersible to maneuver along the direction of the geomagnetic reference points to achieve inertial navigation position information correction. The components of the device of the present invention include a storage unit, a real-time calculation unit and a motion control unit. The execution flow chart is as follows Figure 1 As shown, the following steps are included:

[0030] Step 1: Set an underwater geomagnetic reference point, obtain the position information and geomagnetic characteristic quantity information of the geomagnetic reference point, and store them in a storage unit of the underwater submersible;

[0031] This embodiment places the magnetic sensor and the satellite navigation antenna on the same wooden base and uses a surface ship to tow them to measure the position information and geomagnetic characteristic quantity information of several geomagnetic reference points, specifically:

[0032] Step 1.1: Use the magnetic sensor to measure the three-dimensional magnetic field intensity vector B of the geomagnetic reference point:

[0033] B=[B x B y B z ] T (1)

[0034] In the formula, B x Indicates the eastward component of the geomagnetic field strength at the geomagnetic reference point, B y Indicates the north component of the geomagnetic field strength at the geomagnetic reference point, B z Represents the vertical component of the geomagnetic field intensity at the geomagnetic reference point.

[0035] Step 1.2: Use satellite navigation to measure the position information P of the geomagnetic reference point:

[0036] P=[Lλ] T (2)

[0037] Wherein, L represents the latitude information of the geomagnetic reference point, and λ represents the longitude information of the geomagnetic reference point.

[0038] Step 1.3: Construct the geomagnetic reference point information G(P, B) with the position information P as the horizontal coordinate and the three-dimensional geomagnetic field strength information B as the vertical coordinate, and store the measured geomagnetic reference point information into the storage unit of the underwater submersible.

[0039] Step 2: The real-time computing unit determines whether the underwater submersible has moved to the sea area near the geomagnetic reference point based on the position information measured by the underwater submersible inertial navigation and the pre-established geomagnetic reference point, and decides whether to start geomagnetic bionic navigation without affecting the navigation safety and operation mission of the underwater submersible;

[0040] Step 2.1: In the real-time calculation unit, read the underwater submersible position information measured by inertial navigation, and calculate the position difference Δr between the underwater submersible and the geomagnetic reference point in real time:

[0041]

[0042] In the formula, Indicates the underwater submersible latitude information measured by inertial navigation, Represents the underwater vehicle longitude information measured by inertial navigation.

[0043] Step 2.2: Determine whether the geomagnetic bionic navigation algorithm is activated by comparing the position difference calculated in step 2.1 with the set threshold δ:

[0044] If Δr<δ, it is determined that the underwater submersible has moved to the sea area near the geomagnetic reference point, and steps 3 to 4 are executed to start the geomagnetic bionic navigation algorithm and correct the inertial navigation position;

[0045] If Δr≥δ, it is determined that the underwater submersible is far away from the sea area near the geomagnetic reference point, and the geomagnetic bionic navigation algorithm is not started, and navigation continues according to the original plan.

[0046] Step 3: Release the magnetic sensor carried by the underwater submersible, use the dragging method to measure the geomagnetic information of the current position in real time, and calculate the target maneuvering direction of the underwater submersible;

[0047] Step 3.1: Release the magnetic sensor carried by the underwater submersible and use the dragging method to measure the three-dimensional geomagnetic field intensity vector of the current position in real time

[0048]

[0049] In the formula, represents the eastward component of the geomagnetic field intensity at the location of the underwater submersible, represents the north component of the geomagnetic field intensity at the location of the underwater submersible, It represents the vertical component of the geomagnetic field intensity at the location of the underwater submersible.

[0050] Step 3.2: Calculate the underwater submersible target heading H0 based on the underwater submersible position information measured in real time by the inertial navigation and the geomagnetic reference point information stored in the storage unit in advance:

[0051]

[0052] In the formula, R n Represents the radius of curvature of the Earth's meridian, R e represents the radius of curvature of the earth's circumplex, Δx represents the eastward position difference, and Δy represents the northward position difference.

[0053] Step 4: Start geomagnetic bionic navigation, that is, use the three-dimensional geomagnetic field intensity difference between the current underwater submersible position and the geomagnetic reference point as a guide, and drive the underwater submersible to approach the direction of the geomagnetic reference point through the motion control unit; when it is determined that the underwater submersible has reached the geomagnetic reference point, use the reference point position to replace the inertial navigation position information to achieve inertial navigation position correction, and end geomagnetic bionic navigation;

[0054] Step 4.1: Establish the objective function of the three-dimensional geomagnetic field strength at the current moment:

[0055]

[0056] In the formula, k represents the current time, f(B k ) represents the objective function of the three-dimensional geomagnetic field strength at the current moment.

[0057] Step 4.2: Taking the minimization of the objective function as a constraint, find the movement direction of the underwater submersible at the next moment:

[0058] H k+1 =minf(B k ) (9)

[0059] Step 4.3: The difference between the actual motion direction and the target heading is used as the feedback input of the heading drive control. When the three components of the objective function all tend to 0, it is determined that the three-dimensional geomagnetic field intensity at the current position is infinitely close to the three-dimensional geomagnetic field intensity at the target position (reference point position) and the heading drive control process ends:

[0060] f(B k )<ε (10)

[0061] In the formula, ε represents a three-dimensional vector consisting of three elements tending to 0;

[0062] Step 4.4: At the end of the heading drive control process, the geomagnetic reference point position is used to replace the inertial navigation position information to achieve inertial navigation position correction:

[0063]

[0064] In the formula, Indicates the current latitude information of the underwater submersible. Indicates the longitude information of the underwater submersible at the current moment.

[0065] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for inertial navigation position correction based on geomagnetic bionic navigation, characterized in that: include: Step 1, setting a number of underwater geomagnetic reference points, and obtaining the position information and geomagnetic characteristic quantity information of the geomagnetic reference points; Step 2, during the driving process, the underwater submersible calculates the difference between the position information measured by the inertial navigation and the stored position information of the geomagnetic reference point. If the difference is less than a set threshold, it is determined that the submersible has moved to the sea area near the geomagnetic reference point, and step 3 is executed; Step 3, the underwater submersible measures the three-dimensional geomagnetic field strength of the current position in real time; with the goal of minimizing the difference in the three-dimensional geomagnetic field strength between the current position and the geomagnetic reference point, the movement direction of the underwater submersible at the next moment is calculated, and the difference between the actual movement direction and the target heading is used as the feedback input of the heading drive control to perform navigation control on the underwater submersible, driving the underwater submersible to approach the direction of the geomagnetic reference point; when the intensity difference approaches 0, it is determined that the vehicle has reached the geomagnetic reference point; the geomagnetic reference point position replaces the inertial navigation position information to realize the inertial navigation position correction.

2. The method according to claim 1, characterized in that In the step 1, the magnetic sensor and the satellite navigation antenna are placed on the same wooden base, and the position information and the geomagnetic characteristic quantity information of the geomagnetic reference point are measured by towing the magnetic sensor and the satellite navigation antenna on a surface ship; In step 3, the underwater submersible releases the magnetic sensor and uses a dragging method to measure the geomagnetic information of the current position in real time.

3. The method according to claim 1, characterized in that In step 3, the underwater submersible target heading H0 is calculated based on the underwater submersible position information measured in real time by inertial navigation and the stored geomagnetic reference point position information: Among them, R n Represents the radius of curvature of the Earth's meridian, R e represents the radius of curvature of the earth's circumplex, Δx represents the eastward position difference, and Δy represents the northward position difference; Taking the minimum difference in the three-dimensional geomagnetic field intensity between the current position of the underwater vehicle and the position of the geomagnetic reference point as the constraint condition, the movement direction of the underwater vehicle at the next moment is obtained: H k+1 =minf(B k ) (9) in, is the three-dimensional geomagnetic field strength at the underwater submersible position measured in real time; (B x , B y , B z ) is the three-dimensional geomagnetic field intensity at the geomagnetic reference point; The difference between the actual movement direction of the underwater submersible and the target heading is used as the feedback input of the heading drive control, and the underwater submersible is navigated and controlled to drive the underwater submersible to approach the direction of the geomagnetic reference point.

4. An inertial navigation position correction device using the method according to any one of claims 1 to 3, characterized in that: It includes a magnetic sensor, a storage unit, a real-time computing unit and a motion control unit; Among them, the magnetic sensor is used to measure the geomagnetic information of the current location; The storage unit is used to store the location information of the geomagnetic reference point and the geomagnetic characteristic quantity information; The real-time calculation unit is used to calculate the difference between the position information measured by the inertial navigation and the position information of the geomagnetic reference point stored in the storage unit, and when the difference is less than a set threshold, the motion control unit is turned on; The motion control unit performs navigation control with the goal of minimizing the difference between the geomagnetic information of the current position measured by the magnetic sensor and the geomagnetic information of the geomagnetic reference point stored in the storage unit until the underwater submersible reaches the geomagnetic reference point; the inertial navigation position information is replaced by the position information of the geomagnetic reference point to complete the correction of the inertial navigation position of the underwater submersible.

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