Comparing detection performance of polarization and spatial diversity for indoor GNSS applications

GPS signal detection is limited in indoor areas due to signal attenuation and multipath fading. Considering diversity systems can provide two major benefits: increasing overall average received signal power and decreasing signal fading margins by combining independent signal sources. In this paper, detection performance of spatial and polarization diversity systems applied to the received GPS signals in indoor environments is investigated. Herein, the polarization diversity is formed using two different combinations of orthogonal polarized antennas: one with Right Hand Circular Polarized (RHCP) and Left Hand Circular Polarized (LHCP) antennas and another one by vertical and horizontal antennas. Theoretical comparison of these antenna diversity structures is investigated along with real GPS signal collection in different indoor locations to evaluate their performance experimentally. The diversity gain metric has been introduced to quantify the performance of the combining method theoretically and experimentally. Since diversity gain is a function of correlation coefficient and average signal input, these parameters are measured and compared as well for the target diversity systems.