Joao Fortuna

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Obtaining synoptic observations of dynamic ocean phenomena such as fronts, eddies, oxygen minimum zones and blooms has been challenging primarily due to the large spatial scales involved. Traditional methods of observation with manned ships are expensive and, unless the vessel can survey at high-speed, unrealistic. Autonomous underwater vehicles (AUVs) are(More)
A comparison of the accuracy of visual position measurement in four common subspaces is presented. Principal component analysis (PCA), independent component analysis (ICA), kernel principal component analysis (KPCA) and Fisher's linear discriminant (FLD) are examined for their ability to discriminate positions in a 2D visual subspace. The comparison was(More)
This paper describes a nonlinear controller for following references generated by a Line-of-Sight (LOS) guidance algorithm. Good performance is achieved even in disturbed conditions without integral action by controlling the vehicle's course instead of heading. A cascaded system architecture is employed and a uniform semiglobal exponential stability (USGES)(More)
Over the last decade, ocean sunfish movements have been monitored worldwide using various satellite tracking methods. This study reports the near-real time monitoring of fine-scale (< 10 m) behaviour of sunfish. The study was conducted in southern Portugal in May 2014 and involved satellite tags and underwater and surface robotic vehicles to measure both(More)
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