Nonlinear-model-based SINS/DVL (strapdown inertial navigation system/doppler velocity log) integrated navigation method

Abstract

The invention discloses a nonlinear-model-based SINS / DVL (strapdown inertial navigation system / doppler velocity log) integrated navigation method. The method comprises the following steps of: building a quaternion-based SINS nonlinear speed, posture and position error model according to the working principles of an SINS and a DVL, and confirming an error model of the DVL; building a state equation of the systems according to the error models of the two systems, measuring by taking the difference between the actually-measured speeds of the SINS and the DVL as the quantity, and building a measurement equation of the system; discretizing an actual continuous system to obtain a discrete nonlinear model which is convenient to compute; initializing the system, and computing sampling points and corresponding weight numbers by the discrete nonlinear model and unscented conversion; and sequentially carrying out time update and measurement update on unscented kalman filter on the basis of the discrete nonlinear model according to the constructed Sigma point. After the SINS / DVL integrated navigation system is used, information of each subsystem can be effectively used, and the best of each subsystem can be taken, so that the overall positioning accuracy can be greatly improved; the UKF (unscented kalman filter) estimation can be carried out by the nonlinear model of the SINS / DVL integrated navigation system, so that the positioning error of the system can be effectively reduced and the accurate positioning of the navigation system can be realized better.

Description

technical field [0001] The invention belongs to the technical field of navigation, and relates to a SINS / DVL combined navigation method based on a nonlinear model. Background technique [0002] Human beings are increasingly deepening the development of the ocean, the opening and utilization of ocean resources, and the research and development of underwater vehicles are becoming more and more active. Navigation and positioning is a key technology that affects the development of underwater vehicles, and it is also a bottleneck problem in improving the ability of underwater operations. Since the underwater navigation system has the characteristics of long working hours, complex environment, and few information sources, if a single navigation method is adopted, its navigation accuracy and reliability cannot meet the requirements. If the strapdown inertial navigation system (Strapdown Inertial Navigation System, SINS) and Doppler Velocity Log (DVL) and other systems are properly...

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Problems solved by technology

[0003] In order to solve the problem that the existing SINS linear error model ignores the high-order items, it cannot accurately describe the nonlinear characteristics of the integrated navigation system and the change of the SINS attitude error, so that the estimation accuracy of the position and velocity in the filtering process will decrease with time. The problem of continuous reduction, the present invention provides a kind of SINS / DVL integrated navigation method based on nonlinear model

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