Krzysztof Kurek

Local Positioning for Wireless Sensor Networks

This workshop paper gives an overview of local positioning and tracking principles for wireless sensor networks including recent results of the European project RESOLUTION (reconfigurable systems for mobile local communication and positioning). Measurements of a first demonstrator applying a frequency modulated continuous wave (FMCW) radar principle are presented. The unlicensed ISM band around 5.8 GHz, 150 MHz bandwidth and less than 25 mW effective isotropic radiated transmit power are used. Excellent 3-D positioning accuracies in the order of 4 cm in an anechoic chamber and 18 cm in a conference hall with strong multipath and area of 800 m2 are measured. Furthermore, the results of optimized radio frequency integrated circuits and a suitable compact flash card are outlined.

Attenuation of multipath components using directional antennas and circular polarization for indoor wireless positioning systems

This paper presents results of investigation concerning method for decreasing errors of TOA based indoor wireless positioning systems caused by multipath components. Presented method is based on directional antennas with small side lobes level. Additionally, for attenuation some of multipath components arriving from LOS direction circular polarization antennas are analyzed. The paper describes typical channel profiles for indoor environment and its influence to positioning error. Next, results of simulations are presented. Paper concludes with evaluation of antenna beamwidth and polarization into positioning accuracy based on simulation results.

A 5.8 GHz Local Positioning and Communication System

In this paper, we present a hybrid local positioning and communication system under development within the scope of the EU funded RESOLUTION project. Very stringent requirements to positioning accuracy combined with tight bandwidth limitations demand innovative approaches to combat channel multipath effects. Closely spaced multipath components are the dominant cause of error in the system. Results of system simulations utilizing indoor channel scenarios and measurements using a discrete prototype are presented to prove the possibility of achieving the design goals in spite of limiting spectral regulations.

Measurements and Analysis of the Propagation Channel for Various Indoor Environments

The paper presents measurements results of the propagation channel for three types of indoor environments. Basing on these results statistical analysis and comparison of obtained data are presented. Short review of channel profile measurement techniques are also presented. The paper includes discussion of indoor channel propagation type influence on positioning systems accuracy. Measurements were part of EU VI FP RESOLUTION project, in which WUT was responsible for propagation and antennas work package.

Computer Simulations of the Propagation Channel for Various Indoor Environments

This paper presents the results of computer simulations performed as a part of EU VI FP RESOLUTION project. Conducted research concerns propagation of radio waves inside large halls. Channel characteristics influencing on accuracy of microwave positioning system were determined by means of ray-tracing method. Various propagation scenarios, locations of transmitter and radiation patterns of transmitting antenna were taken into consideration.

Closely Spaced Paths Effect Mitigation for Indoor Location Systems

Paper presents a proposal of method for closely spaced paths mitigation for indoor location system based on spread spectrum signals. At the beginning issue of closely spaced paths influence for the accuracy of TO A determination is explained. In the following part results of indoor propagation simulations are presented. These simulations show relationship between delays and directions of arrival of power delay profile components. The proposal of simple four-element null steering antenna array, which can mitigate this effect, is proposed. The paper contains also results of measurements showing influence of multipath propagation to coarse code synchronization.

Integrated Communications System for the Remote Operation of Unmanned Aerial Vehicle

The aim of the paper is to present the concept of the integrated system dedicated for communication and remote operation of the unmanned aerial vehicle (UAV). In the paper, the concept and realization of this kind of wireless communications system is presented. The system consists of two integrated solutions – unidirectional broadcast transmission of video, audio and data from UAV to the operators within the mobile command centre and two-way communication with the telemetry and control subsystem. The systems are integrated within the single chassis and placed on the UAV to ensure proper operation of the flying robot. The specific elements of the system are presented as well as main requirements and development methods are also discussed in the paper.

Antenna diversity impact to indoor wireless TOA-based positioning systems accuracy

This paper presents analysis of antenna diversity impact to distance measurement error of indoor TOA-based positioning systems. First channel impulse response shaping methods and indoor TOA-based systems accuracy aspects are shortly discussed. In the following part of the paper obtained results for two types of data (ray-tracing simulations, measurements) and for various TOA detection techniques are presented. Paper concludes with summary of our research.

Investigation of 2D phased smart antenna array for LEO satellite system

This paper presents a 2D phased antenna array that can be used in the LEO satellite system. A basic 2times2 sub-array, using circular polarisation, has been design and realised. The influence of mutual coupling between antennas and impedance matching of beam-forming network on characteristics of the array has been considered

Space platform for student CubeSat pico-satellite

The paper presents a satellite platform developed in Institute of Radioelectronics, Warsaw University of Technology, for present and future student pico-satellite missions. The platform consists of all systems necessary to proper operation of payload equipment that could be placed on the satellite: mechanical structure, power supply unit, communications and control system.