Enhanced Gnss Indoor Signal Detectability Using Polarization Diversity

GPS signal polarization changes upon reflection from right hand circular polarization (RHCP) to elliptical polarization, formed from both right and left hand polarization. In this paper, the polarization diversity of received signals is investigated and is utilized to improve GPS signal detection performance in indoor environments. The design of the detection algorithm is based on target values of the probability of detection and probability of false alarm metrics associated with each search hypothesis. This leads to either the Estimator Correlator (EC) or Equal Gain Combiner (EG) structures, the performance of each of which is analyzed here. To examine the proposed method, a large number of data sets in various indoor locations are collected using a commercial dual polarization antenna mounted on a linear motion table. The complex correlation coefficient is obtained for various SV's. In addition, the empirical ROC curves are derived to analyze the performance of the proposed approach. The diversity gain is defined and is derived for this method. A considerable enhancement in performance of new designed detector based on the polarization diversity can be observed.