Analysis and tuning of a low cost inertial navigation system in the ARIES AUV
Authors
Vonheeder, Steven R.
Subjects
Advisors
Healey, Anthony J.
Date of Issue
2006-12
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
Autonomous underwater vehicle navigation is a complex problem of state estimation. Accurate navigation is made difficult due to a lack of reference navigation aids or use of the Global Positioning System (GPS) that could establish the vehicles position. Accurate navigation is critical due to the level of autonomy and range of missions and environments into which an underwater vehicle may be deployed. Navigational accuracy depends not only on the initialization and drift errors of the low cost Inertial Motion Unit (IMU) gyros and the speed over ground sensor, but also on the performance of the sensor fusion filter used. This thesis will present the method by which an Extended Kalman Filter (EKF) was tuned after installation of an IMU in the ARIES Autonomous Underwater Vehicle. The goal of installing the IMU, analyzing the navigational results and tuning the EKF was to achieve navigational accuracy in the horizontal plane with a position error of less than one percent of distance traveled when compared to GPS. The research consisted of IMU installation and software modifications within the vehicle to fully realize the design goal. Data collection and analysis was conducted through field experiments and computer simulation. A significant result of this work was development of a pseudo-adaptive algorithm to vary the measurement noise values in selected channels to for a desired response in the filter and improve accuracy and precision in the state estimates.
Type
Thesis
Description
Series/Report No
Department
Mechanical and Astronautical Engineering (MAE)
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
xvi, 122 p. : ill. ;
Citation
Distribution Statement
Approved for public release; distribution is unlimited.