Title :
Double Stage NCO-Based Carrier Tracking Loop in GNSS Receivers for City Environmental Applications
Author :
Wenfei Guo ; Kunlun Yan ; Hongping Zhang ; Xiaoji Niu ; Chuang Shi
Author_Institution :
GNSS Res. Center, Wuhan Univ., Wuhan, China
Abstract :
A double stage NCO (numerically controlled oscillator)-based tracking loop with a new frequency discriminator is proposed to track the carrier frequency of the GNSS signal in signal degraded environments. The structure can be easily implemented and modified with conventional GNSS receivers, and the new frequency discriminator has absolute linearity in a wide pull in range. The principle and performance of the method are described and analyzed in detail. Simulation and field test with a software receiver show that this method can effectively track a weak signal compared with other presented methods in an open loop.
Keywords :
discriminators; oscillators; radio receivers; satellite navigation; GNSS receivers; GNSS signal; city environmental applications; double stage NCO-based carrier tracking loop; frequency discriminator; numerically controlled oscillator; signal degraded environments; software receiver; Equations; Frequency estimation; Frequency locked loops; Global Positioning System; Receivers; Time-frequency analysis; Tracking loops; GNSS receiver; frequency estimation; open loop tracking; sinc function;
Journal_Title :
Communications Letters, IEEE
DOI :
10.1109/LCOMM.2014.2350489