This paper describes an efficient mechanism for correcting estimation errors inherent in existing WLAN-based localization systems. One of major problems in such localization systems is to degrade the estimation accuracy due to lacks of sufficient training data and temporal changes in received signal strength indications. We propose a location correction technique based on geographical locality of the estimation errors. This proposed correction technique is designed for exploiting users collaboration to improve the efficiency of the correction. More specifically, each surveyed location is associated with knowledge of error corrections that have been conducted by users, and is stored into a database. The system improves the usability of users' correction by presenting the knowledge corresponding to the estimated location.
