Robust performance in dynamic positioning systems

Performance Characterization of Positioning in LTE Systems

This paper presents low-level models of cellular LTE signals along with an architecture for a software-defined radio (SDR) that is capable of (1) extracting the essential parameters for navigation from the received LTE signals and (2) acquiring and tracking real LTE signals transmitted from multiple base stations. Moreover, a method for obtaining time-of-arrival (TOA) estimates that is highly r...

Robust services in dynamic systems

Autotuning Aspects for Dynamic Positioning Systems

This paper considers aspects related to the problem of automatic tuning (autotuning) of dynamic positioning (DP) controllers for marine surface vessels. Autotuning involves automatic adjustment of controller parameters for shifting vessel operational conditions (VOCs), which encompass changing vessel dynamics and different operational tasks. A controller with fixed gains cannot behave equally w...

Robust dynamic positioning of ships with disturbances under input saturation

In the presence of unknown time-varying disturbances and input saturation, this paper develops a robust nonlinear control law for the dynamic positioning (DP) system of ships using a disturbance observer, an auxiliary dynamic system, and the dynamic surface control (DSC) technique. The disturbance observer is constructed to provide the estimates of unknown time-varying disturbances, the auxilia...

Robust Optimization of Dynamic Systems

This thesis is about robust optimization, a class of mathematical optimization problems which arise frequently in engineering applications, where unknown process parameters and unpredictable external influences are present. Especially, if the uncertainty enters via a nonlinear differential equation, the associated robust counterpart problems are challenging to solve. The aim of this thesis is t...