Mobile GPS carrier phase tracking using a novel intelligent dual‐loop receiver |
| |
Authors: | Wei‐Lung Mao An‐Bang Chen |
| |
Affiliation: | 1. Department of Electronic Engineering, National Formosa University, Yunlin County, Taiwan, Republic of China;2. Assistant Professor.;3. MediaTek Inc., Hsinchu, Taiwan, Republic of China |
| |
Abstract: | Carrier phase information is necessary for accurate measurements in global positioning system (GPS) applications. This paper presents a novel intelligent GPS carrier tracking loop with variable‐bandwidth characteristics for fast acquisition and better tracking capability in the presence of dynamic environments. Our dual‐loop receiver is composed of a frequency‐locked loop‐assisted phase‐locked loop structure, the fuzzy controllers (FCs), and the ATAN discriminator functions. The soft‐computing FCs provide the time‐varying loop gains to perform accurate and reliable control of the dual‐loop paradigm. Once the phase dynamic errors become large under kinematic conditions, the fuzzy loop gains increase adaptively and achieve rapid acquisition. On the other hand, when the tracking errors approach zero in the steady state, the loop gains decrease and the corresponding dual‐loop receiver returns to a narrowband system. Four types of carrier phase signals, i.e. phase offset, decaying sinusoidal phase jitter, frequency offset, and frequency ramp offset, are considered to emulate realistic mobile circumstances. Simulation results show that our proposed receiver does achieve a superior performance over conventional tracking loops in terms of faster settling time and wider acquisition range while preventing the occurrence of cycle slips. Copyright © 2008 John Wiley & Sons, Ltd. |
| |
Keywords: | global positioning system (GPS) dual‐loop receiver phase‐locked loop (PLL) frequency‐locked loop (FLL) fuzzy controller carrier phase tracking variable bandwidth |
|
|