A Comparative Study of a Low Doppler Shift in a Carrier Tracking Loop for GPS

This paper compares a carrier tracking scenario when a received Global Positioning System (GPS) signal has low Doppler frequency. It is shown that if the Numerically Controlled Oscillator (NCO) is quantized to 1 bit, the carrier tracking loop is unable to keep track of the incoming signal which leaves the tracking loop oscillating between the upper and lower bounds of the tracking loop bandwidth. One way of overcoming this problem is presented and compared with another existing solution, found in the literature, providing comparative results from the use of real-recorded off the air GPS L1 signals. Results show that the proposed method performs better tracking performance compared with the existing solution which it requires much less hardware complexity.

Introduction: Exploring the Comparative in Socio-Legal Studies

Among the diverse approaches to comparison in socio-legal studies those that employ qualitative research, richness of detail, and attention to context are the focus of this special issue. The Introduction draws on comparative law and social science literature to argue that comparison amongst studies of laws in contexts can follow different trajectories: the comparison may start from an assumption of similarity—in form, purposes, or context—in order to identify significant differences; or it may identify significant similarity across social and cultural divides. What unites many of the projects of comparison undertaken by qualitative empirical researchers is that the points of relevant comparison are identified within the complexity of the empirical studies at hand; and they are allowed to emerge, or change, as the researcher comes to understand the facts and issues more deeply.