• A Machine Learning Approach for Estimating Air Data Parameters 

      Borup, Kasper Trolle; Fossen, Thor I.; Johansen, Tor Arne (Journal article; Peer reviewed, 2019)
      This paper presents a method for estimating the air data parameters for a small fixed-wing, unmanned aerial vehicle (UAV) using an arrangement of low-cost MEMS-based pressure sensors embedded in the surface of the UAV. The ...
    • A Neural Network Approach to Control Allocation of Ships for Dynamic Positioning 

      Skulstad, Robert; Li, Guoyuan; Zhang, Houxiang; Fossen, Thor I. (Journal article; Peer reviewed, 2018)
      Dynamic Positioning (DP) of ships is a control mode that seeks to maintain a specific position (stationkeeping) or perform low-speed maneuvers. In this paper, a static Neural Network (NN) is proposed for control allocation ...
    • A UAV Ice Tracking Framework for Autonomous Sea Ice Management 

      Leira, Frederik Stendahl; Johansen, Tor Arne; Fossen, Thor I. (Chapter; Peer reviewed, 2017)
      This paper describes an unmanned aerial vehicle (UAV) ice tracking framework for use in sea ice management applications. The framework is intended to be used in an ice management scenario where the UAV should detect and ...
    • A Uniformly Semiglobally Exponentially Stable Nonlinear Observer for GNSS- and Camera-Aided Inertial Navigation 

      Fusini, Lorenzo; Fossen, Thor I.; Johansen, Tor Arne (Conference object; Journal article; Peer reviewed, 2014)
      In this paper a nonlinear observer for estimation of position, velocity, acceleration, attitude and gyro bias of an Unmanned Aerial Vehicle (UAV) is proposed. The sensor suite consists of an Inertial Measurement Unit (IMU), ...
    • A virtual vertical reference concept for aided inertial navigation at the sea surface 

      Bryne, Torleiv Håland; Rogne, Robert Harald; Fossen, Thor I.; Johansen, Tor Arne (Journal article; Peer reviewed, 2017)
      When trying to capture the heaving motion of a marine vessel in waves, conventional position references such as global navigation satellite systems fall short in many cases. Because of design and satellite geometry, the ...
    • Aerodynamic modeling of the Skywalker X8 Fixed-Wing Unmanned Aerial Vehicle 

      Gryte, Kristoffer; Hann, Richard; Alam, Mushfiqul; Rohac, Jan; Johansen, Tor Arne; Fossen, Thor I. (Chapter, 2018)
      With advanced control, estimation and simulation requirements in unmanned aerial systems comes the need for sophisticated aerodynamic models. This paper reviews two common means for establishing such models; numerical ...
    • Attitude Estimation by Multiplicative eXogenous Kalman Filter 

      Stovner, Bård Nagy; Johansen, Tor Arne; Fossen, Thor I.; Schjølberg, Ingrid (Journal article, 2018)
      This paper presents a novel attitude estimator called the multiplicative exogenous Kalman filter. The estimator inherits the stability properties of a nonlinear observer and the near-optimal steady-state performance of the ...
    • Authenticated Encryption Methods for Feedback Control Systems 

      Solnør, Petter (Master thesis, 2021)
      Tilbakekoplingssystemer krever at signaler sendes mellom sensorer, tilstandsestimatorer, regulatorer og aktuatorer. Disse signalene er sårbare for tyvlytting, som gjør at uautoriserte aktører kan få kjennskap til potensielt ...
    • Automatic detection, classification and tracking of objects in the ocean surface from UAVs using a thermal camera 

      Leira, Frederik Stendahl; Johansen, Tor Arne; Fossen, Thor I. (Journal article; Peer reviewed, 2015)
      The use of unmanned aerial vehicles (UAVs) that can operate autonomously in dynamic and dangerous operational environments are becoming increasingly common. In such operations, object detection, classification and tracking ...
    • Autonomous Docking Control System for the Otter USV: A Machine Learning Approach 

      Bjering Strand, Henrik (Master thesis, 2020)
      Denne masteroppgaven utforsker muligheten for å bruke dyp forsterkende læring (eng. deep reinforcement learning, DRL) til å utvikle et autonomt dokkingsystem for en underaktuert overflatefarkost. Autonome marine fartøy er ...
    • Autonomous recovery of a fixed-wing UAV using a net suspended by two multirotor UAVs 

      Klausen, Kristian; Fossen, Thor I.; Johansen, Tor Arne (Journal article; Peer reviewed, 2018)
      This article presents a novel recovery method for fixed‐wing unmanned aerial vehicles (UAVs), aimed at enabling operations from marine vessels. Instead of using the conventional method of using a fixed net on the ship deck, ...
    • A Co-operative Hybrid Model For Ship Motion Prediction 

      Skulstad, Robert; Li, Guoyuan; Fossen, Thor I.; Wang, Tongtong; Zhang, Houxiang (Peer reviewed; Journal article, 2021)
      Dynamic models of ships have been widely used for model-based control and short-term prediction in the past. Identifying the parameters of such models has mainly been done through scaled model tests, full scale tests or ...
    • Continuous-Curvature Path Generation using Fermat's Spiral 

      Lekkas, Anastasios; Dahl, Andreas R; Breivik, Morten; Fossen, Thor I. (Journal article; Peer reviewed, 2013)
      This paper proposes a novel methodology, based on Fermat's spiral (FS), for constructing curvature-continuous parametric paths in a plane. FS has a zero curvature at its origin, a property that allows it to be connected ...
    • Cooperative Control for Multirotors Transporting an Unknown Suspended Load under Environmental Disturbances 

      Klausen, Kristian; Meissen, Chris; Fossen, Thor I.; Arcak, Murat; Johansen, Tor Arne (Journal article; Peer reviewed, 2019)
      In this paper, we develop a cooperative control algorithm for a group of multirotor unmanned aerial vehicles (UAVs) transporting a suspended payload of unknown mass. In addition, the vehicles are subjected to unknown ...
    • Data-Based Modelling of Ships for Motion Prediction and Control Allocation 

      Skulstad, Robert (Doctoral theses at NTNU;2021:383, Doctoral thesis, 2021)
      Vessels operating on the surface of the ocean are exposed to an array of disturbances. These may come in terms of environmental disturbances, but may also come from signal loss. Modelling the behaviour of ships using ...
    • Dead Reckoning of a Fixed-Wing UAV with Inertial Navigation Aided by Optical Flow 

      Fusini, Lorenzo; Johansen, Tor Arne; Fossen, Thor I. (Chapter; Peer reviewed, 2017)
      This paper provides experimental results for dead reckoning of a fixed-wing UAV using a nonlinear observer (NLO) and a more recent tool called eXogenous Kalman Filter (XKF), which uses the NLO itself as a first-stage filter. ...
    • Dead Reckoning of Dynamically Positioned Ships: Using an Efficient Recurrent Neural Network 

      Skulstad, Robert; Li, Guoyuan; Fossen, Thor I.; Vik, Bjørnar; Zhang, Houxiang (Journal article; Peer reviewed, 2019)
      When a ship experiences a loss of position reference systems, its navigation system typically enters a mode known as dead reckoning (DR) to maintain an estimate of its position. Commercial systems perform this task using ...
    • Design of inertial navigation systems for marine craft with adaptive wave filtering aided by triple-redundant sensor packages 

      Bryne, Torleiv Håland; Fossen, Thor I.; Johansen, Tor Arne (Journal article; Peer reviewed, 2017)
      Marine craft feedback control systems typically require estimates of position, velocity and heading where the wave-induced motions should be suppressed. This paper presents a strapdown inertial navigation system with ...
    • Design of Moving-mass and Dive-plane Control Systems for AUVs 

      Løvdal, Marcus Nicolai (Master thesis, 2021)
      I denne oppgaven er litteratursøk om «moving-mass» aktuering and kontroll for fartøy i forskjellige bruksområder gjennomført, inkludert forskjellige konfigurasjoner av aktueringen. Fordeler og ulemper med å implementere ...
    • Estimation of Angle of Attack and Sideslip Angle applied in an Airborne Wind Energy System 

      Schiager, Per Johannes Andresen (Master thesis, 2019)
      Hovedbidraget i denne oppgaven er implementasjon og anvendelse av en metode for estimering av angrepsvinkler for ubemannede luftfartøy - anvendt på teknologi for utnyttelse av høydevindkraft. Den implementerte metoden er ...