Underwater vehicle all-attitude determination method based on magnetic gradient tensor measurement

Abstract

The invention belongs to the field of underwater geomagnetic aided navigation, and particularly relates to an underwater vehicle all-attitude determination method based on magnetic gradient tensor measurement. The method comprises the steps of: under a carrier system, establishing a three-dimensional rectangular coordinate system to obtain five components of magnetic gradient tensor; extracting five isolated components of the magnetic gradient tensor under a geographical system from the prestored magnetic gradient tensor database; substituting the results into a non-linear equation set about q0, q1, q2 and q3; substituting quaternion q0, q1, q2 and q3 to a transformation matrix between a substitution carrier system and the geographical system to obtain the estimated value of a pitch angle theta. The underwater vehicle locating technology based on magnetic anomaly inversion has the characteristics of being low in cost, high in sensitivity, high in anti-interference capability, free from accumulative error and the like; the problem that a single magnetometer can not independently determine the attitude by depending on the geomagnetic field can be solved; an independent and concealed way is provided for underwater vehicle attitude estimation.

Description

technical field [0001] The invention belongs to the field of underwater geomagnetic aided navigation, and in particular relates to a method for determining the full attitude of an underwater carrier based on geomagnetic gradient tensor measurement. Background technique [0002] Underwater submersibles can maintain a high positioning accuracy based on the inertial / geomagnetic matching integrated navigation system, but long-term underwater navigation will cause a few degrees of error in the attitude angle of the submarine, which will cause underwater weapon launches that depend on the attitude of the navigation system. The larger error seriously restricts the combat effectiveness of the submarine. Therefore, underwater vehicle attitude determination technology is one of the core contents of underwater vehicle navigation system. GPS attitude determination technology loses the characteristics of high autonomy and concealment of underwater navigation system, and at the same time...

AI Technical Summary

Problems solved by technology

GPS attitude determination technology loses the characteristics of high autonomy and concealment of underwater navigation system, and at the same time, it is restricted by complex underwater terrain and cannot normally receive GPS signals

The accuracy and resolution of the optical attitude determination system decrease with the increase of the distance between the target and the optical sensor. Optical noise, stray light, shadow occlusion, etc. may cause the failure of the attitude determination system, so the attitude determination system based on optical measurement is difficult to apply underwater

At present, the attitude measurement method of the star sensor, which is considered to be the most accurate, is mainly used for spacecraft, satellites and other space vehicles. This method gives the attitude of the carrier relative to the inertial space, and cannot determine the attitude independently. It needs to be used in combination with the inertial navigation system and is expensive. expensive

The attitude measurement method based on the strength of the earth’s magnetic field is susceptible to the influence of various disturbance magnetic fields around due to its limitation in principle, while the magnetic field generated by the soft ferromagnetic material on the carrier is related to the state of the carrier’s motion, so it is difficult to accurately correct, especially for large inclinations. magnetic field at angle

On the other hand, a single geomagnetic field strength cannot provide sufficient attitude measurement information

The present invention proposes an attitude determination method based on the magnetic field gradient tensor measurement, which eliminates the influence of the interference magnetic field by extracting the magnetic field gradient information, solves the problem that a single magnetometer cannot rely on the earth's magnetic field to determine the attitude independently, and at the same time estimates the attitude of the underwater vehicle Provides an autonomous, covert path

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