Time synchronization is an essential building block in wireless sensor networks but is challenging due to low-precision oscillators and limited computational power of cheap devices. A novel synchronization solution for such scenarios is now proposed by Wasif Masood together with his advisors Christian Bettstetter and Jorge F. Schmidt from the University of Klagenfurt.
New packages for the Robot Operating System (ROS) are available for autonomous exploration of unknown environments using collaborating mobile robots equipped with cameras. The software offers wireless ad hoc communications between robots, merging of maps from different robots, and coordinated selection of exploration frontiers. A prototype with four robots was built that demonstrates its functionality in an indoor environment.
The mathematical modeling of pulse-coupled biological oscillators offers a fully decentralized and scalable approach for time synchronization. There is a broad spectrum of work on pulse-coupled oscillators in physics, biology, neuroscience, and other disciplines. The communications engineering community has been interested to transfer these results to the synchronization of nodes in wireless networks. A one-to-one transfer is infeasible due to the differences between wireless and biological communications. Several extensions and modifications are required with respect to delays, noise, multihop communications, and sync words.
Metal parts in factory halls disturb wireless communications. ICT researchers from Klagenfurt invented a new transmission technique and are now looking for partners for implementation. Although the need for fast and reliable data transmission via WLAN increases in production halls, the technology is still limited. Mobile machinery, forklifts, and robots disturb the radio link between transmitter and receiver. Wolfgang Rössler reports. Read online: Publication Nikolaj Marchenko, Torsten Andre, Günther Brandner, Wasif Masood, and Christian Bettstetter. An Experimental Study of Selective Cooperative Relaying in Industrial Wireless Sensor Networks. IEEE Transactions on Industrial Informatics, vol. 10, no. 3, pp. 1806-1816, August 2014.
The cDrones team at the University of Klagenfurt and Lakeside Labs develops a system for multiple unmanned aerial vehicles (UAVs) to provide a high-quality aerial overview image of a given area of interest. Evsen Yanmaz, PostDoc in the project, explains: “It only takes a few mouse clicks for operators to define the area to be observed. To provide for autonomous coverage of the area, the software automatically computes where to take a picture and optimizes the flight routes for all UAVs. During the mission, UAVs can constantly be observed at the base station. The pictures taken during flight are immediately shown in their GPS positions on a map. A rough 3D structure is extracted from the captured images which enables us to improve mosaicking results to obtain a nice aerial overview image.”
Cooperative relaying has been developed for wireless communications to mitigate the negative effects of small-scale fading caused by multipath propagation. A huge amount of research has been done in the past ten years to assess benefits and drawbacks of such techniques by simulations and analytical means. It is surprising, however, that only few studies with real-world measurements in realistic environments were published so far. The goal of a research team led by Christian Bettstetter at Klagenfurt’s NES institute is to contribute toward closing this research gap. Based on an implementation of a simple cooperative relaying protocol on the programmable radio platform WARP, measurements were conducted to evaluate the packet delivery performance in a car-to-car communications scenario. The results will be published in IEEE Wireless Communications Letters. “We studied the ratio and temporal correlation of packet delivery for suburban and highway environments using three cars serving as sender, relay, and destination,” Günther Brandner, a researcher in the project team, explains.
The Lakeside Labs project cDrones performs research on networked unmanned aerial vehicles (UAVs) and their application to emergency and disaster response. Current work focuses on UAV routing, image stitching, and system integration. The video below demonstrates the following use case: An emergency response person specifies an area of interest in a map, and the system software computes appropriate waypoints and routes. Using GPS navigation, the UAVs autonomously overfly the specified area and deliver pictures to the ground station. The ground station runs an online image stitching algorithm creating a real-time update of the area map. In this way, the emergency assistants obtain an up-to-date overview image of the area. The service platform enables coordinated flights of multiple UAVs and is independent of the used UAV technology; it can also provide input to UAV simulations.