Implementation and Analysis of Signal Tracking Loops for Software Defined GPS Receiver

A number of methods have been developed to enhance the robustness of Global Positioning System (GPS) receivers when there are a limited number of visible satellites. Vector tracking is one of them. It utilizes information from all channels to aid the processing of individual channels to generate receiver positions and velocities. This paper analyzes relationships among code phase, carrier frequency, and receiver position and velocity, and presents a vector loop-tracking algorithm using an Extended Kalman filter implemented in a Matlab-based GPS software receiver. Simulated GPS signals are generated to test the proposed vector tracking method. The results show that when some of the satellites are blocked, the vector tracking loop provides better carrier frequency tracking results for the blocked signals and produces more accurate navigation solutions compared with traditional scalar tracking loops.

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A filter algorithm for receiver tracking loops assisted by inertial information

Journal of Navigation ◽

10.1017/s0373463321000916 ◽

2021 ◽

pp. 1-11

Author(s):

Zhifeng Han ◽

Zheng Fang

Keyword(s):

Integration Time ◽

Frequency Error ◽

Loop Filter ◽

Signal Tracking ◽

Phase Jitter ◽

Loop Bandwidth ◽

Tracking Ability ◽

Negative Effect ◽

Tracking Loops ◽

Signal Environment

Abstract In traditional satellite navigation receivers, the parameters of tracking loop such as loop bandwidth and integration time are usually set in the design of the receivers according to different scenarios. The signal tracking performance is limited in traditional receivers. In addition, when the tracking ability of weak signals is improved by extending the integration time, negative effect of residual frequency error becomes more and more serious with extension of the integration time. To solve these problems, this paper presents out research on receiver tracking algorithms and proposes an optimised tracking algorithm with inertial information. The receiver loop filter is designed based on Kalman filter, reducing the phase jitter caused by thermal noise in the weak signal environment and improving the signal tracking sensitivity. To confirm the feasibility of the proposed algorithm, simulation tests are conducted.

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A Cascade Tracking Loop for Weak GPS Signals

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.719-720.1116 ◽

2015 ◽

Vol 719-720 ◽

pp. 1116-1123 ◽

Cited By ~ 1

Author(s):

Ming Xing Shi ◽

Bi Yu Tang ◽

Ao Peng

Keyword(s):

Carrier Phase ◽

Frequency Estimation ◽

Measuring Error ◽

Phase Estimation ◽

Weak Signal ◽

Gps Receiver ◽

Tracking Loop ◽

Signal Tracking ◽

Tracking Process ◽

Cascade Structure

It’s important to get accurate carrier phase and frequency information when using a standalone GPS receiver. In weak signal applications, to keep a stable tracking is hard to achieve because measuring error will be huge when the SNR is low. Different methods are used to improve the SNR before the detector in a tracking process, such as coherence integration. And this paper keeps eyes on a different viewpoint, on how to refine estimation results. A cascade structure is introduced for weak signal tracking. This structure is divided into two levels. In the first level, raw phase estimation and accurate frequency estimation is provided to achieve stable work in low CNR environment. In the second level, the raw phase estimation is refined to achieve accurate tracking requirement. This cascade structure can also work jointly with any other SNR-improving technology to get a better performance.

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Evaluation of solar radio bursts' effect on GPS receiver signal tracking within International GPS Service network

Radio Science ◽

10.1029/2004rs003066 ◽

2005 ◽

Vol 40 (3) ◽

pp. n/a-n/a ◽

Cited By ~ 24

Author(s):

Zhiyu Chen ◽

Yang Gao ◽

Zhizhao Liu

Keyword(s):

Solar Radio ◽

Radio Bursts ◽

Gps Receiver ◽

Solar Radio Bursts ◽

Service Network ◽

Signal Tracking

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GPS Receiver Performance Enhancement via Inertial Velocity Aiding

Journal of Navigation ◽

10.1017/s0373463300001260 ◽

2001 ◽

Vol 54 (1) ◽

pp. 105-117 ◽

Cited By ~ 2

Author(s):

Dah-Jing Jwo

Keyword(s):

Performance Enhancement ◽

Transfer Functions ◽

Gps Receiver ◽

Tracking Loop ◽

Tracking Errors ◽

Dynamic Tracking ◽

Tracking Loops ◽

Receiver Performance ◽

Velocity Information ◽

Lock In

An integrated GPS/INS navigation system can employ inertial velocity information to produce a more robust system. For a stand-alone GPS receiver, decreasing the receiver tracking loop bandwidth reduces the probability of losing lock in a jamming or interference environment if vehicle dynamics are low. However, reduced bandwidth increases tracking errors when dynamics are present. Beyond a certain limit, it causes a serious degradation in the dynamic tracking loop performance. Providing inertial velocity aiding to the receiver tracking loops is an effective and popular treatment to help resolve this problem. In this paper, performance of the GPS receiver tracking loops using inertial velocity aiding will be investigated. Different types of tracking loops, from 1st to 3rd order, are covered. Following the discussion of the system architecture and derivation of the related transfer functions for the tracking loops, both with and without aiding, the system performance, including transient response, steady-state error, and noise bandwidth is evaluated.

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A FLL-PLL Cooperative GNSS Weak Signal Tracking Framework

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.551.470 ◽

2014 ◽

Vol 551 ◽

pp. 470-477 ◽

Cited By ~ 2

Author(s):

Yang Liu ◽

Yan Bo Zhu

Keyword(s):

High Performance ◽

Signal Attenuation ◽

Signal Tracking ◽

Navigation Solution ◽

Delay Locked Loop ◽

Dynamic Framework ◽

Tracking Loops ◽

Navigation Signals ◽

Navigation Information ◽

New Framework

Navigation signals should be steadily tracked to allow the extraction of navigation information, and support the calculation of navigation solution. Generally, extraction of navigation information is realized by GNSS tracking loops, which need to implement two critical operations: 1) tracking parameters should be precisely estimated in order to reliably decode the navigation message. 2) Successive tracking method of navigation information. This paper proposes a novel tracking framework using dynamic FLL assisting PLL strategy and a loop state detection monitor. The new framework extends traditional phase and delay locked loop (PLL/DLL) tracking framework, and contributions mainly lie in two parts. A dynamic framework for parameters adjustment is proposed to avoid tracking failure due to the change of environment, which is complemented in a FLL-PLL cooperative framework. Experimental results demonstrate the advantages of our algorithm compared with standard PLL/DLL framework. It is shown that the algorithm proposed is more suitable for tracking under signal attenuation situation, while maintaining high performance at the same time.

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INS-Assisted GNSS Signal Tracking Modeling and Assessment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.271-273.603 ◽

2011 ◽

Vol 271-273 ◽

pp. 603-608

Author(s):

Ping Ye ◽

Xing Qun Zhan ◽

Gang Du

Keyword(s):

Inertial Sensor ◽

Inertial Navigation ◽

Phase Lock Loop ◽

Signal Tracking ◽

Gnss Receiver ◽

Tracking Condition ◽

Tracking Ability ◽

Tracking Loops ◽

Tracking Behavior ◽

Gyro Drift

To improve the tracking performance of GNSS receiver in signal-attenuated environments, phase lock loop (PLL) and delay lock loop (DLL) assisted with Inertial Navigation System (INS) measurements are considered. Combining inertial navigation principles with signal processing, this paper proposes a simplified but efficient mathematical model of INS-assisted second-order tracking loops. Compared with unaided GNSS receiver, the tracking behavior of INS-assisted receiver is quantitatively analyzed, and the kind of INS suitable to guarantee the tracking condition is determined. The results indicate that an INS with 1 deg/h gyro drift is necessary to support PLL, and MEMS inertial sensor with 100 deg/h gyro drift is sufficient to aid DLL to keep favored tracking ability.

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