Distance-measurement error associated with antenna phase-center displacement in time-reference radio positioning systems

This paper presents a tutorial discussion of the effects of antenna phase-center displacement on distance determination in time-correlation radio positioning systems. A technique to determine the antenna phase-center displacement as a function of observation angle is reviewed. A simple method to determine the distance error versus observation angle, derived from the antenna phase-center displacement, is then presented. Numerical distance-error predictions, determined directly from antenna phase-center displacement, are presented for a Yagi and a log-periodic antenna used in a commercial UHF radio distance-measurement system. Finally, the measured distance error versus observation angle for these antennas as determined in several field trials is presented, validating the numerical predictions.