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Wireless LANs not only provide an effective means of communication, but also allow to extract information about the location of mobile stations. Numerous Wireless LAN location systems have been proposed in the past, yet it is difficult to compare the performance of different systems, since the conditions under which these systems are evaluated differ considerably. Hence, the accuracy information presented in literature varies widely, even for conceptually identical systems. This paper proposes to evaluate the performance of location systems in standardised test environments. To this end, existing location systems are discussed to assess their information requirements and their reported accuracies. Subsequently, the requirements for benchmarks in the context of Wireless LAN location systems are established. To conclude, a publicly available benchmark is presented against which different Wireless LAN location systems can be compared.

Abstract. Markov localization has been successfully deployed in robotics using highly precise distance sensors to determine the location and pose of mobile robots. In this setting the scheme has shown to be robust and highly accurate. This paper shows how this approach has been adapted to the problem of locating wireless LAN clients in indoor environments using highly fluctuating radio signal strength measurements. A radio propagation model is used to determine the expected signal strength at a given position in order to avoid tedious offline measurements. Some of the issues that had to be addressed include expressing the calculated signal strengths in terms of probability density functions and detecting movement of the mobile terminal solely on the basis of radio measurements. The conducted experiments show that the proposed technique provides a median error of less than 2 m even when there is no line-of-sight to an access point.

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