Abstract-This paper considers the application for tracking of one mobile emitter using a sequence of frequency difference of arrival (FDOA) measurements obtained by single pair of receivers at a time. We suppose there is only one unmanned aerial vehicle (UAV) as emitter without data link relation problems, such as disconnection of data link or false measurements. Each FDOA measurement defines a region of possible emitter locations around a unique hyperbola. These analysis leads to the Cramér-Rao lower bound (CRLB) for estimation of movements. Through the analysis we propose the manner for tracking through the error-ellipsoids acquired from each CRLB. Since the performance measure is the length of error ellipsoid axes, we compare the effects of various environments.Index Terms-Frequency difference of arrival (FDOA), Cramér-Rao lower bound (CRLB), unmanned aerial vehicle (UAV), tracking, ground station (GS)