1 Methodology for Comparing Two Carrier Phase Tracking Techniques Dina Reda Salem, Cillian O’Driscoll and Gérard Lachapelle Position, Location And Navigation (PLAN) Group Department of Geomatics Engineering Schulich School of Engineering, University of Calgary Email: dina.salem(at)ucalgary(dot)ca website: http://plan.geomatics.ucalgary.ca/ Received on 10 June 2010 Accepted on 22 April 2011 Abstract The carrier phase tracking loop is the primary focus of the current work. In particular, two carrier phase tracking techniques are compared, the standard phase tracking loop, i.e. the Phase Lock Loop (PLL) and the Extended Kalman filter (EKF) tracking loop. In order to compare these two different techniques and taking into consideration the different models adopted in each, it is important to bring them to one common ground. In order to accomplish this, the equivalent PLL for a given EKF has to be determined in terms of steady-state response to both thermal noise and signal dynamics. A novel method for experimentally calculating the equivalent bandwidth of the EKF is presented and used to evaluate the performance of the equivalent PLL. Results are shown for both the L1 and L5 signals. Even though the two loops are designed to track equivalent dynamics and to have equivalent carrier phase standard deviations, the EKF outperforms the equivalent PLL both in terms of the transient response and sensitivity. Keywords Phase lock loop; Kalman filter tracking; L1 signal; L5 signal 1. Introduction GPS signal tracking has been a widely studied issue in the literature. It is critical to ensure accurate tracking before attempting to use the navigation measurements. Several methods were previously introduced and commonly used for tracking. The most common method, which is referred to in the paper as standard tracking, was originally used for various communication systems. It models the incoming system as having deterministic dynamics. Examples of these loops are Phase Lock Loop (PLL), frequency lock loop (FLL) and delay lock loop (DLL). Another method, which is also widely used, is based on the Kalman filter theory. "The final publication is available at www.springerlink.com".