Localisation of Wireless LAN Nodes using

Localisation of Wireless LAN Nodes using - Localisation of...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Localisation of Wireless LAN Nodes using Accurate TDoA Measurements Reinhard Exel, Georg Gaderer, and Patrick Loschmidt Austrian Academy of Sciences Institute for Integrated Sensor Systems Viktor Kaplan Strae 2 A-2700 Wr. Neustadt { Reinhard.Exel, Georg.Gaderer, Patrick.Loschmidt } @oeaw.ac.at Abstract Time based localisation methods like GPS are widely used for outdoor navigation, whereas indoor navigation is typ- ically performed only on a cell-basis or based on the Received Signal Strength Indicator. Since RSSI is not able to fulfil all current requirements, Time of Arrival and Time Difference of Arrival based approaches have recently gained focus. As time based localisation has high demands on the quality of the timestamps, we propose a special receiver architecture for IEEE 802.11b capable of a timestamping accuracy in the sub- nanosecond range. The receivers operation is demonstrated by an FPGA based wireless physical layer device implementation. Experimental results show an improvement in terms of accuracy by a factor of 100 up to 1000 over COTS wireless LAN hardware. This enables accurate localisation in wireless LANs just by adding of timing receivers. 1 I. INTRODUCTION Over the last decade there has been a significant trend to connect consumer electronic goods with a wireless connection. The reason for this was not only the increased flexibility and reduced cabling costs but also the improved dependabil- ity of wireless communication. Despite the system inherent drawbacks of a wireless connection, namely sharing the same medium and a high packet drop rate compared to wired connections, wireless communication is widely used. Usually wireless systems lack one desirable feature: Accurate locali- sation. The presented approach is to complement the wireless communication system by a localisation method based on Time Difference of Arrival (TDoA) measurements. Numerous applications for the localisation information can be considered: Complementing security concepts, channel allocation planning based on the position of a node, or location dependent services. Time based localisation methods like Time of Arrival (ToA) or TDoA have several advantages compared to the Received Signal Strength Indicator (RSSI) methods. Since the main idea behind RSSI is a known relationship between distance and path-loss, RSSI has problems with obstacles attenuating the signal and also with greater distances due to the fact that the free space attenuation increases with the logarithm of the distance. Time based methods are not influenced by RSSI, but 1 The work presented in this paper is founded by the FIT-IT Project -WiFi Embedded Position Determination and Security in Wireless Fidelity Networks. Grant Number 813310, the EU Project flex WARE under grant number 224350 as well as the province of Lower Austria and the European Regional Development Fund....
View Full Document

This note was uploaded on 10/01/2010 for the course ELEC 6111 taught by Professor Brown during the Spring '10 term at E. Illinois.

Page1 / 6

Localisation of Wireless LAN Nodes using - Localisation of...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online