Improvement of Carrier Phase Tracking Based on a Joint Vector Architecture

Shaohua Chen,Yang Gao

doi:10.1155/2017/9682875

Shaohua Chen, Yang Gao

Open Access

https://doi.org/10.1155/2017/9682875

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Abstract

Carrier phase measurements are essential to high precision positioning. Usually, the carrier phase measurements are generated from the phase lock loop in a conventional Global Navigation Satellite System (GNSS) receiver. However there is a dilemma problem to the design of the loop parameters in a conventional tracking loop. To address this problem and improve the carrier phase tracking sensitivity, a carrier phase tracking method based on a joint vector architecture is proposed. The joint vector architecture contains a common loop based on extended Kalman filter to track the common dynamics of the different channels and the individual loops for each channel to track the satellite specific dynamics. The transfer function model of the proposed architecture is derived. The proposed method and the conventional scalar carrier phase tracking are tested with a high quality simulator. The test results indicate that carrier phase measurements of satellites start to show cycle slips using the proposed method when carrier noise ratio is equal to and below 15 dB-Hz instead of 21 dB-Hz with using the conventional phase tracking loop. Since the joint vector based tracking loops jointly process the signals of all available satellites, the potential interchannel influence between different satellites is also investigated.

Highlights

Carrier phase is tracked by the phase lock loop (PLL) in a conventional Global Navigation Satellite System (GNSS) receiver
Carrier phase is tracked by the phase lock loop (PLL) in a conventional GNSS receiver
The results indicate that no cycle slips are present for all satellites the standard deviation of the carrier phase measurements is large

Summary

Introduction

Carrier phase is tracked by the phase lock loop (PLL) in a conventional GNSS receiver. The bandwidth, for instance, should be narrowed in order to decrease the thermal noise error but narrowing the bandwidth will increase the oscillator noise error and dynamic stress error With those challenges in mind, this paper will design a tracking architecture to address the problems. Leimer and Kohli [3] proposed a phase noise mitigation method which first used all available satellites to estimate the oscillator phase noise and remove this oscillator error before the correlator They did not consider the common dynamics influence. A carrier phase tracking approach based on a joint vector architecture is proposed for GNSS receivers. The proposed joint vector tracking method adds a common loop based on extended Kalman filter (EKF) to estimate the common error for different channels.

Joint Vector Phase Lock Loop

Test and Performance Comparison

Interchannel Influence of Different Satellites in the Joint Vector Tracking

Conclusions