Error Analysis of the Distance and Distance Difference for SSSD-based Wireless Location: Part II-Experimental Results

Mobile location services (MLS) in wireless networks continue to advance. The promise of new MLS is for a substantial part concentrated on location estimation. Depending on the distance and distance-difference estimated from the stationary signal-strength-difference (SSSD) measurements, the location of the mobile caller is provided by using the circular and hyperbolic algorithms respectively. However, its performance is limited because the accuracy of the distance and distance-difference are affected by two impairment factors: one factor is the SSSD measurement error and one factor is an error resulted from the detection of the reference distance, called the detection error. In this paper with a commercial cellular 900 MHz wireless network measurement in urban environment, the theoretical aspects treated in part I of this paper is extended here to account for the analysis of the detection error in the reference distance and of the SSSD measurement error, as well as of the error correction. Based on the experimental results, the advantage associated with the proposed correction method is strongly emphasized to suppress the larger error that was initially encountered.