Accession Number ADA558942
Title Multiple-Vehicle Resource-Constrained Navigation in the Deep Ocean.
Publication Date Sep 2011
Media Count 150p
Personal Author B. L. Reed
Abstract This thesis discusses sensor management methods for multiple-vehicle fleets of autonomous underwater vehicles, which will allow for more efficient and capable infrastructure in marine science, industry, and naval applications. Navigation for fleets of vehicles in the ocean presents a large challenge, as GPS is not available underwater and dead-reckoning based on inertial or bottom- lock methods can require expensive sensors and suffers from drift. Due to zero drift, acoustic navigation methods are attractive as replacements or supplements to dead-reckoning, and centralized systems such as an Ultra-Short Baseline Sonar (USBL) allow for small and economical components onboard the individual vehicles. Motivated by subsea equipment delivery we present model- scale proof-of-concept experimental pool tests of a prototype Vertical Glider Robot (VGR), a vehicle designed for such a system. Due to fundamental physical limitations of the underwater acoustic channel, a sensor such as the USBL is limited in its ability to track multiple targets at best a small subset of the entire fleet may be observed at once, at a low update rate. Navigation updates are thus a limited resource and must be efficiently allocated amongst the fleet in a manner that balances the exploration versus exploitation tradeoff. The multiple vehicle tracking problem is formulated in the Restless Multi-Armed Bandit structure following the approach of Whittle in 108, and we investigate in detail the Restless Bandit Kalman Filters priority index algorithm given by Le Ny et al. in 71. We compare round-robin and greedy heuristic approaches with the Restless Bandit approach in computational experiments. For the subsea equipment delivery example of homogeneous vehicles with depth-varying parameters, a suboptimal quasi-static approximation of the index algorithm balances low landing error with safety and robustness.
Keywords Acoustic navigation
Autonomous navigation
Deep oceans
Robots
Sonar
Tracking
Ultra-Short Baseline Sonar(USBL)
Underwater vehicles
Vertical Glider Robot(VGR)


 
Source Agency Non Paid ADAS
NTIS Subject Category 62 - Computers, Control & Information Theory
76D - Navigation Systems
Corporate Author Massachusetts Inst. of Tech., Cambridge. Joint Program in Applied Ocean Science and Engineering.
Document Type Thesis
Title Note Master's thesis.
NTIS Issue Number 1219
Contract Number N00014- 09-1-0700

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