TY  - JOUR
A1  - Gageik, Nils
A1  - Reinthal, Eric
A1  - Benz, Paul
A1  - Montenegro, Sergio
T1  - Complementary Vision based Data Fusion for Robust Positioning and Directed Flight of an Autonomous Quadrocopter
N2  - The present paper describes an improved 4 DOF (x/y/z/yaw) vision based positioning solution for fully 6 DOF autonomous UAVs, optimised in terms of computation and development costs as well as robustness and performance. The positioning system combines Fourier transform-based image registration (Fourier Tracking) and differential optical flow computation to overcome the drawbacks of a single approach. The first method is capable of recognizing movement in four degree of freedom under variable lighting conditions, but suffers from low sample rate and high computational costs. Differential optical flow computation, on the other hand, enables a very high sample rate to gain control robustness. This method, however, is limited to translational movement only and performs poor in bad lighting conditions. A reliable positioning system for autonomous flights with free heading is obtained by fusing both techniques. Although the vision system can measure the variable altitude during flight, infrared and ultrasonic sensors are used for robustness. This work is part of the AQopterI8 project, which aims to develop an autonomous flying quadrocopter for indoor application and makes autonomous directed flight possible.
KW  - Autonomous UAV
KW  - Quadrocopter
KW  - Quadrotor
KW  - Vision Based
KW  - Positioning
KW  - Data Fusion
KW  - Directed Flight
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113621
ER  - 
TY  - JOUR
A1  - Ali, Quasim
A1  - Montenegro, Sergio
T1  - A Matlab Implementation of Differential GPS for Low-cost GPS Receivers
N2  - A number of public codes exist for GPS positioning and baseline determination in off-line mode. However, no software code exists for DGPS exploiting correction factors at base stations, without relying on double difference information. In order to accomplish it, a methodology is introduced in MATLAB environment for DGPS using C/A pseudoranges on single frequency L1 only to make it feasible for low-cost GPS receivers. Our base station is at accurately surveyed reference point. Pseudoranges and geometric ranges are compared at base station to compute the correction factors. These correction factors are then handed over to rover for all valid satellites observed during an epoch. The rover takes it into account for its own true position determination for corresponding epoch. In order to validate the proposed algorithm, our rover is also placed at a pre-determined location. The proposed code is an appropriate and simple to use tool for post-processing of GPS raw data for accurate position determination of a rover e.g. Unmanned Aerial Vehicle during post-mission analysis.
KW  - marine navigation
KW  - Global Positioning System (GPS)
KW  - Matlab
KW  - Differential GPS (DGPS)
KW  - GPS Reciever
KW  - Unmanned Aerial Vehicle (UAV)
KW  - RINEX Format
KW  - Global Navigation Satellite System (GNSS)
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113618
ER  - 
TY  - JOUR
A1  - Montenegro, Sergio
A1  - Ali, Qasim
A1  - Gageik, Nils
T1  - A review on Distributed Control of Cooperating MINI UAVs
N2  - Mini Unmanned Aerial Vehicles (MUAVs) are becoming popular research platform and drawing considerable attention, particularly during the last decade due to their multi-dimensional applications in almost every walk of life. MUAVs range from simple toys found at electronic supermarkets for entertainment purpose to highly sophisticated commercial platforms performing novel assignments like offshore wind power station inspection and 3D modelling of buildings. This paper presents an overview of the main aspects in the domain of distributed control of cooperating MUAVs to facilitate the potential users in this fascinating field. Furthermore it gives an overview on state of the art in MUAV technologies e.g. Photonic Mixer Devices (PMD) camera, distributed control methods and on-going work and challenges, which is the motivation for many researchers all over the world to work in this field.
KW  - Mini Unmanned Aerial Vehicle
KW  - Distributed Control
KW  - Cooperative UAV
KW  - Autonomous UAV
KW  - Mobile Sensor Network
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113009
ER  -