A Novel Extended Tracking Range DLL for AltBOC Signals

Abstract

Code tracking linear range and the code phase tracking jitter have always been opposing ends of the design criteria of a code lock loop in direct-sequence spread-spectrum communication systems. New modulation techniques used in Global Navigation Satellite Systems (GNSS) offer better code tracking jitter and multipath performance by sharpening the correlation triangle. However the linear tracking range is reduced which directly results in poor dynamics and low signal strength performance of the tracking loop. The problem is most severe in the sophisticated Alternate Binary Offset Carrier (AltBOC) modulation. This paper proposes a method to extend a loop's tracking range without affecting the jitter performance in the existing linear range of the code tracking loop.