Performance of the NeQuick G iono model for single-frequency GNSS timing applications

Piriz, R.; Roldan, P.; Golcz, R.; Moriana, C.; Leute, J.

doi:10.1109/eftf.2016.7477769

Cited by 5 publications

(5 citation statements)

References 3 publications

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“…The so-called NeQuick model has been implemented in the Galileo system (European Commission 2015), which provides improved modeling of the ionosphere compared to the Klobuchar model implemented in GPS. This is advantageous for single-frequency users (Píriz et al 2016) and is demonstrated in Fig. 9.…”

Section: Using Galileo Signals As Time and Frequency Referencementioning

confidence: 99%

On the possibility of getting traceable time and frequency measurements via GNSS receivers

et al. 2020

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The realization of Coordinated Universal Time, one of the tasks of the International Bureau of Weights and Measures, relies on a network of international time links which currently is organized in a star-like scheme that links all contributing laboratories. GPS signal reception is the technique most widely employed by the laboratories. The PTB currently plays a unique role in the process due to its function as the central pivot in the time transfer between the participating laboratories. We discuss how the PTB meets its obligations to the international timekeeping community as well as to its users in Germany. In its role as an National Metrology Institute (NMI), PTB is entrusted with the realization and dissemination of legal time in Germany. The services were offered to the public support measurements and timing applications traceable to the national and international standards to be made in calibration laboratories and in many industrial sectors. We thus discuss the meaning and definition of traceability, how different GNSS systems can be used to establish traceability and their performance in doing so.

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Section: Using Galileo Signals As Time and Frequency Referencementioning

confidence: 99%

On the possibility of getting traceable time and frequency measurements via GNSS receivers

et al. 2020

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“…In particular, height-dependent electron density profiles above numerous foot points have to be evaluated, leading to a large computational load [ 23 ]. The effort required for running NeQuick-G has been estimated to be 60 times larger than that needed for the Klobuchar model [ 24 ]. In order to reduce the computational burden, an alternative application of the NeQucik-G model is presented in the following section.…”

Section: Nequick-gmentioning

confidence: 99%

“…The main limitation of the NeQuick-G model is its computational load [ 23 , 24 ]. This aspect is of foremost importance for smartphones, which have limited computational capabilities.…”

Section: Introductionmentioning

confidence: 99%

NeQuick-G and Android Devices: A Compromise between Computational Burden and Accuracy

Gioia

Borio

2020

Sensors

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Ionospheric delay is one of the largest errors affecting Global Navigation Satellite System (GNSS) positioning in open-sky conditions, and different methods are currently available for mitigating ionospheric effects including dual-frequency measurements and corrections from augmentation systems. For single-frequency standalone receivers, the most widely used approach to correct ionospheric delays is to rely on a model. In this respect, Klobuchar and NeQuick-G Ionospheric Correction Algorithm (ICAs) are the approaches adopted by GPS and Galileo, respectively. While the latter outperforms the Klobuchar model, it requires a significantly higher computational load, which can limit its exploitation in some market segments such as smartphones. In order to foster adoption of the NeQuick-G model in this type of device, a smart application of NeQuick-G is proposed. The solution relies on the assumption that ionospheric delays are practically constant over short time intervals. Thus, the update rate of the ionospheric correction computation can be significantly reduced. This solution was implemented, tested, and evaluated using real data collected with a static smartphone in an ad hoc set-up. The impact of reducing the ionospheric correction update rate has been evaluated in terms of processing time, of ionospheric correction deviations and in the Ranging Error (RE) and position domains. The analysis shows that a significant reduction of the processing time can be obtained with negligible degradation of the navigation solution.

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“…NeQuick G is based on a more complex algorithm than Klobuchar. Implementation of NeQuick G capability on receivers also needs bit more preparation, since the model assumes availability of the CCIR maps, and dip latitudes grid file (Paakki et al 2015;Piriz et. al 2016).…”

Section: Nequick G Modelmentioning

confidence: 99%

“…Angrisano et al (2013) simulated the NeQuick G parameters for 3 days of May 2012 and three stations at different magnetic locations in the world, and compared the results to Klobuchar in position domain, obtaining comparable performance in position domain. Piriz et al (2016) compared both models in range domain (ionospheric delay level), using actual data for the first three months of 2016. For the low-latitude station analyzed, NeQuick G was marginally better than Klobuchar.…”

Section: Introductionmentioning

confidence: 99%

Klobuchar and Nequick G Ionospheric Models Comparison for Multi-GNSS Single-Frequency Code Point Positioning in the Brazilian Region

2019

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One of the main error sources in GNSS positioning comes from the ionosphere, an atmospheric layer that stays in the signal path between the satellite and the receiver. For single frequency positioning, the ionospheric effects can be minimized by using an ionospheric model e.g. Klobuchar or NeQuick G. These models are respectively associated to GPS and Galileo systems through their navigation messages, which broadcast coefficients that describe the worldwide ionospheric behavior, and the calculated ionospheric delay is then applied in the pseudorange observations. In this paper, it is presented a comparison between these two models in multi-GNSS (GPS and Galileo) single frequency point positioning, considering two Brazilian stations at different magnetic latitudes, and covered months of weak and strong ionospheric activity from 2013 to 2018. The results indicate a better performance of NeQuick G model compared to the Klobuchar. Considering all the analyzed periods and stations, Klobuchar improves the positioning accuracy in 16% and 50% in periods of weak and strong ionospheric activity, respectively, while NeQuick G improves the accuracy in 31% and 55%.

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Performance of the NeQuick G iono model for single-frequency GNSS timing applications

Cited by 5 publications

References 3 publications

On the possibility of getting traceable time and frequency measurements via GNSS receivers

On the possibility of getting traceable time and frequency measurements via GNSS receivers

NeQuick-G and Android Devices: A Compromise between Computational Burden and Accuracy

Klobuchar and Nequick G Ionospheric Models Comparison for Multi-GNSS Single-Frequency Code Point Positioning in the Brazilian Region

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