The switching carrier tracking loop under severe ionospheric scintillation

Fantinato, Samuele; Rovelli, Davide; Crosta, Paolo

doi:10.1109/navitec.2012.6423056

Cited by 7 publications

(8 citation statements)

References 11 publications

(11 reference statements)

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“…These techniques have been shown to deliver poor estimates or even lose lock under harsh propagation conditions [2,3]. Several improved PLL-based techniques have been proposed in the literature: cooperative loops [4], switching architectures [5], adaptive bandwidth approaches [6,7] or noise reduction techniques [2]. Refer to the recent and up-to-date survey on robust carrier tracking techniques [8] and the references therein for a complete overview of PLL-based architectures.…”

Section: State-of-the-artmentioning

confidence: 99%

On the identifiability of noise statistics and adaptive KF design for robust GNSS carrier tracking

Vilà‐Valls¹,

Closas²,

Fernández‐Prades³

2015

2015 IEEE Aerospace Conference

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Carrier synchronization is of paramount importance in any communications or positioning system. Mass-market Global Navigation Satellite System (GNSS) receivers typically implement traditional carrier tracking techniques based on well-established phase-locked loop architectures, which are only reliable in quite benign propagation conditions. Under nonnominal harsh propagation conditions, the signal may be affected by shadowing, strong fading, multipath or severe ionospheric scintillation, and thus, traditional architectures are not valid anymore and there exists an actual need for robust tracking solutions. Several approaches to overcome the conventional PLL limitations have appeared during the last decade, being the Kalman filter (KF) based architectures the most promising research line. The main drawback of standard KFs is the assumption of perfectly known process and measurement noise statistics, a knowledge that is always constrained by the system model accuracy. Beyond heuristic solutions, a general framework for the design of adaptive KFs correctly dealing with both process and measurement noises, that would be of capital importance for the practitioner, has not been established. The main goal of this contribution is to provide a clear answer to this fundamental question. It is shown that the main driver on the KF performance is not the adjustment of the measurement noise but the adequate tuning of the process noise statistics. Within this framework, a comprehensive discussion is given for the correct design of adaptive KF architectures for robust carrier tracking applications, where the key idea is to use two independent noise statistics estimation strategies to sequentially adapt both parameters. The design choice is supported by a discussion on the identifiability of the noise statistics' parameters. Simulation results are provided showing the need of fully adaptive solutions, and the achieved performance gain of KF-based architectures when compared to traditional tracking loops.

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Section: State-of-the-artmentioning

confidence: 99%

On the identifiability of noise statistics and adaptive KF design for robust GNSS carrier tracking

Vilà‐Valls¹,

Closas²,

Fernández‐Prades³

2015

2015 IEEE Aerospace Conference

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“…In fact a FLL, although less accurate than the PLL, is less vulnerable to scintillation effects. Another possible approach consists in using the FLL as a backup solution in case of a loss of lock [8]. In order to select the optimum loop parameters an alternative strategy is to exploit adaptive tracking schemes which tune the loop filter bandwidth according to an optimization criteria depending on the estimated C/N 0 and signal dynamics [9].…”

Section: Designing a Carrier Tracking Architecture Robust Under Scintmentioning

confidence: 99%

“…S δf = S δf -clock + S δf -scintillation (8) In equations (7) and (8) the sum operation is valid since the clock and the scintillation noise are independent. Moreover, the phase error contributor due to scintillation is computed as…”

Section: Designing a Carrier Tracking Architecture Robust Under Scintmentioning

confidence: 99%

Kalman Filter Based PLL Robust Against Ionospheric Scintillation

Susi¹,

Andreotti²,

Aquino³

2014

Mitigation of Ionospheric Threats to GNSS: An Appraisal of the Scientific and Technological Outputs of the TRANSMIT Project

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“…Another possible approach is to replace the PLL with a frequency-locked loop (FLL), which is more robust under harsh situations but also less accurate. When high accuracy is required, the FLL can be used as a backup solution to replace the PLL in case of loss of lock (Fantinato et al 2012). Alternatively, FLL-assisted PLL techniques can be employed (Xu et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Tuning a Kalman filter carrier tracking algorithm in the presence of ionospheric scintillation

et al. 2017

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Strong ionospheric electron content gradients may lead to fast and unpredictable fluctuations in the phase and amplitude of the signals from Global Navigation Satellite Systems (GNSS). This phenomenon, known as ionospheric scintillation, is capable of deteriorating the tracking performance of a GNSS receiver, leading to increased phase and Doppler errors, cycle slips and also to complete losses of signal lock. In order to mitigate scintillation effects at receiver level, the robustness of the carrier tracking loop, the receiver weakest link under scintillation, must be enhanced. Kalman filter (KF)-based tracking algorithms are particularly suitable to cope with the variable working conditions imposed by scintillation. However, the effectiveness of this tracking approach strongly depends on the accuracy of the assumed dynamic model, which can quickly become inaccurate under randomly variable situations. This study first shows how inaccurate dynamic models can lead to a KF suboptimum solution or divergence, when both strong phase and amplitude scintillation are present. Then, to overcome this issue, it proposes two self-tuning KF-based carrier tracking algorithms, which self-tune their dynamic models by exploiting the knowledge about scintillation that can be achieved through scintillation monitoring. The algorithms have been assessed with live equatorial data affected by strong scintillation. Results show that the algorithms are able to maintain the signal lock and provide reliable scintillation indices when classical architectures and commercial ionospheric scintillation monitoring receivers fail.

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The switching carrier tracking loop under severe ionospheric scintillation

Cited by 7 publications

References 11 publications

On the identifiability of noise statistics and adaptive KF design for robust GNSS carrier tracking

On the identifiability of noise statistics and adaptive KF design for robust GNSS carrier tracking

Kalman Filter Based PLL Robust Against Ionospheric Scintillation

Tuning a Kalman filter carrier tracking algorithm in the presence of ionospheric scintillation

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