Comparison of 802.11 Wireless Transmitter Localization Techniques

Abstract

The presence of an unsecured 802.11 access point is a major information security threat to government and business organizations. Thus it is necessary to accurately identify and isolate these devices. The purpose of this study is to evaluate various collection techniques used to geographically locate these unsecured access points. Using low cost hardware to passively capture data, a comparison is made between the use of omnidirectional and directional antennas. Stationary as well as mobile collections are performed for each of these antenna types. Various propagation models and estimation algorithms are compared to determine which method provides the most accurate results over varying and uncertain wireless environments. Testing methods utilizing directional antennas exhibited very accurate results for a range of collection environments. Even in the presence of severe multipath, the analysis techniques were able to identify these reflections and compensate. The methods employing omnidirectional antennas, however, produced inconsistent overall results. While the propagation model estimates were accurate for some sites, they were highly inaccurate for others. Due to the varying environment types that are encountered during wireless data collection, the use of generalized propagation models to provide source location is unreliable.