Wireless Access Point Localization Using Nonlinear Least Squares and Multi-Level Quality Control

Locations of WiFi access points (APs) are important for WiFi positioning when a propagation model is used. The pre-surveyed propagation parameters, such as the path-loss exponent, are usually not available when localizing the APs in a new environment. This letter introduces a novel method that estimates the AP locations and the parameters of the received signal strength (RSS) propagation model simultaneously using the weighted nonlinear least squares (NLLS) method. This method can run on consumer portable devices autonomously in real time without any a-priori information, and eliminate the need of pre-survey. Another contribution of this letter is to introduce a multi-level quality control mechanism, and utilize the statistical testing method in AP localization and propagation parameters (PPs) determination for the first time. Indoor experiments show that the proposed method provided more promising results than previous methods.