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Underwater Navigation Methods Based on Gravity and Environmental Features

Author: WangWenJing
Tutor: SunFeng
School: Harbin Engineering University
Course: Precision instruments and machinery
Keywords: Underwater geophysical navigation Gravity assisted navigation Synchronous composition positioning Contour matching algorithm Gravity / INS navigation system Data Association
CLC: U666.1
Type: PhD thesis
Year: 2009
Downloads: 490
Quote: 6
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Abstract

Inertial navigation system to meet long-term implementation of the tasks of submerged submarines and other underwater vehicle autonomous navigation system and the hidden aspects of the requirements, but its accuracy was not perfect the need other auxiliary navigation system to correct its well known with time growing positioning error. The marine geophysical navigation method has the advantages of high precision positioning without surfaced just can compensate for the inertial navigation system in the positioning accuracy of less than ideal underwater submarine underwater vehicle auxiliary means of navigation and positioning. The thesis focuses on underwater geophysical gravity and environmental characteristics-based navigation and positioning method. By the the ocean topographic maps constructed gravity gradient map view of the objective situation in our country at this stage not measured gravity gradient data, rectangular rectangular prism, and the corresponding gradient map generated according to the topographic map of the two real waters, as the gravity gradient matching algorithm the basis of research and testing. The shortcomings of most of the existing gravity matching algorithm is not available in the larger case of the INS position error, in-depth study of probability neural network based on the principle advantage of the use of neural networks in the classification issue, proposed probabilistic neural network-based gravity gradient matching algorithm, and discuss the impact of different gradient component combination algorithm to match the success probability as the network input, inertial navigation system to solve the large position error correction. The simulation tests proved the gradient matching algorithms without INS information can effectively reduce the position error of the navigation system, can be used in a submersible position error larger. -Depth analysis of the INS position error in the calculation of normal gravity matching navigation system to the introduction of the mechanism of the observation error value can not be ignored, proposed gravimeter measurement and gravity anomaly database transformed from the the gravimeter measurement principle start gravity and then matching strategy to fundamentally eliminate the adverse impact of this observation errors bring. Characteristics of the full use of short-term high-precision inertial navigation system, propose an alternative applicable in the case of INS position error contour matching algorithm, based on the value of function optimization priori gravity map search, tracking and the decision-making process to find the most similar track as INS Track shape matching Track. In the simulation the simulated gravity map and the real gravity map shows that the case of the normal sea conditions and medium accuracy inertial navigation, contour matching algorithm can obtain a higher positioning accuracy, apply to the INS large position error of water under correction. In order to further speed the inertial navigation system, the attitude error correction, gravity match the position correction based on the information provided by the navigation system, inertial navigation system error model for the system equations, gravity position INS output location matching algorithm. The difference between the observables constructed gravity / inertial integrated navigation system, accurate estimates of INS position, velocity and attitude errors by Kalman filter. Relationship between the analysis of INS position heading error and gyro drift gravity matching algorithm matching position for position re-adjusted value, the application of three positioning correction method to estimate the gyro constant drift, and through the simulation prove the use of gravity assisted The navigation results gyro drift estimate the feasibility and effectiveness. Not mapping or gravity changes too gentle sea, gravity-assisted navigation system will not work, this time can be used as a gravity-assisted positioning algorithm based on the characteristics of synchronous composition of the marine environment of the alternative method of navigation for reducing the growth rate of the navigation error . The papers depth study of the basic principles of synchronous composition localization algorithm, and nonlinear system model for underwater carrier to discuss the expansion process of prediction, observation, and the state of the system, using the extended Kalman filtering technique to achieve the algorithm. The regional exploration and sea-crossing two sets of simulation test results proved that, based on the the synchronous composition positioning of extended Kalman filter algorithm can effectively slow down the growth rate of error of submarines and other underwater vehicle to improve the positioning accuracy of the navigation system. Existing data association method in the calculation of the lack of complexity and associated stability, an improved data association methods, and use of simulation proved the algorithm can get a good smaller computational complexity associated effect online data as synchronous composition positioning algorithm associated.

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