Real-time triple-frequency cycle slip detection and repair method under ionospheric disturbance validated with BDS data

Tian, Zhongda; Sui, Lifen; Xu, Ya; Jia, Xiaolin; Xiao, Guorui; Tian, Yuan; Zhang, Qinghua

doi:10.1007/s10291-018-0727-9

Cited by 19 publications

(20 citation statements)

References 15 publications

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“…Secondly, the constraint on the tropospheric noise is too loose, which leads to systematic errors in the solution [44]. Thirdly, there may be undetected small cycle slips in the QZSS observations, and they lead to worse effects on the combined positioning [45]. All of these reasons require improved strategies, constraints and methods for specific stations, which will be studied as our future work.…”

Section: ) Static Pppmentioning

confidence: 99%

An Improved QZSS Satellite Clock Offsets Prediction Based on the Extreme Learning Machine Method

Zhou

Zhu

et al. 2020

IEEE Access

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The Japanese Quasi-Zenith Satellite System (QZSS) has been developed as a GPS (Global Positioning System) complementary system to improve positioning accuracy in the Asia-Pacific region. However, the accuracies of ultra-rapid predicted clocks are not high enough for real-time applications, so it is still a challenge problem. This paper focuses on the clock predictions of the new QZSS constellation. Based on the QZSS clock periodic characteristics, an improved clock prediction method combining the spectrum analysis model (SAM) and extreme learning machine (ELM) is proposed with abbreviation as iELM. The key parameters of iELM are selected carefully including the number of hidden layer nodes and activation function. Further, the input length of the iELM network is optimized and discussed thoroughly. For the purpose of assessing the performance of the proposed algorithm, the clock prediction accuracies are compared among GBU-P (the ultra-rapid predicted orbits/clocks provided by GFZ (Deutsches GeoForschungsZentrum)), SAM and iELM methods. It is demonstrated that iELM keeps in a high level of accuracy below 1.0ns with the predicted time increasing from 0 to 18h, and a little larger during the next six hours. And the QZO (Quasi-Zenith Orbit) satellites perform better than GEO (Geostationary Earth Orbit) satellite. Furthermore, precise point positioning (PPP) for both static and kinematic modes are experimentally studied for 13 IGS (International GNSS (Global Navigation Satellite System) Service) MGEX (Multi-GNSS Experiment) stations in the longitude range between 100°E and 180°E. In the static PPP mode, the iELM method is verified to be effective for the GPS/QZSS constellation as positioning accuracy is improved by 28.3%, 57.7% and 47.4% on average in the east, north and up component with respect to GPS/QZSS GBU-P results. Nearly 70.0% stations achieve sub-decimeter accuracy in the vertical component. As for the kinematic PPP, the iELM method based on GPS/QZSS observations performs much better than the others for shorter convergence time and better positioning accuracy. Compared with GPS/QZSS GBU-P, iELM takes at most a half time to get convergence, and the accuracy is enhanced by 27.6%, 23.7% and 13.9% on average in the east, north and up direction respectively.

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Section: ) Static Pppmentioning

confidence: 99%

An Improved QZSS Satellite Clock Offsets Prediction Based on the Extreme Learning Machine Method

Zhou

Zhu

et al. 2020

IEEE Access

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“…Zhao et al (2015) used three combinations, namely extra-wide lane, wide lane, and narrow lane, to determined cycle slips sequentially in three cascaded steps and results showed that this method performed well under high ionospheric activity [12]. Zeng et al (2018) used triple-frequency combinations to detect and repair cycle slip under ionospheric disturbance with BDS data [13].…”

Section: Introductionmentioning

confidence: 99%

Real-Time Triple-Frequency Cycle Slip Detection and Repair Algorithm Based on the Optimal Fixing Probability

Wang¹,

Chen²,

Liu³

et al. 2020

RADIOENGINEERING

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Global Navigation Satellite System (GNSS) is now being speedily expanded to our daily life, but the positioning precision still can hardly meet the demands of many applications, such as approaching landing system on airports. Due to the development of GNSS, triple-frequency signals are now available which can contribute to positioning precision. Positioning precision cannot be improved by triple-frequency carrier phases until cycle slips are detected and repaired. Traditional cycle slip detection and repair algorithms choose detection combinations with long wavelength, weak ionospheric delay and small combination noise separately. However, these three conditions cannot be satisfied simultaneously. In this paper, these three conditions are not considered separately. On the contrary, the eventual fixing probability of cycle slip is set as the optimal goal to determine the three detection combinations. The combined ionospheric delay and noise in cycles can be regarded as bias and variance respectively. The proposed algorithm has been tested on observations with simulated and real cycle slips. The results show that the proposed algorithm can detect and repair even single cycle slips in real time effectively.

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“…In other words, these techniques cannot be processed instantaneously and might fail to detect small cycle slips under high-multipath conditions [ 13 , 14 ]. Furthermore, the ionosphere combination is vulnerable to severe ionospheric storm since the remaining bias of the ionospheric variation makes it difficult to detect small cycle slips [ 13 , 15 , 16 ]. The probability of occurrence of these insensitive pairs is incredibly small [ 10 ], but it is still considered an integrity threat to a system requiring high-integrity performance.…”

Section: Introductionmentioning

confidence: 99%

“…To overcome these limitations, triple-frequency signals, which allow many additional combinations such as the extra-wide lane combination and ionospheric reduced combination, are being emphasized for improving performance [ 17 , 18 , 19 , 20 , 21 ]. Especially, many novel combinations of GPS and BeiDou, which are the currently available triple-frequency signals, have been proposed for cycle slip detection without an insensitive pair even under a high-ionospheric storm [ 15 , 16 , 22 ]. Despite the many advantages of triple-frequency signals, most of the receivers and GNSS satellites only provide dual-frequency signals, currently.…”

Section: Introductionmentioning

confidence: 99%

A New Algorithm for High-Integrity Detection and Compensation of Dual-Frequency Cycle Slip under Severe Ionospheric Storm Conditions

Kim

Song

et al. 2018

Sensors

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Many strategies for treating dual-frequency cycle slip, which can seriously affect the performance of a carrier-phase-based positioning system, have been studied over the years. However, the legacy method using the Melbourne-Wübbena (MW) combination and ionosphere combination is vulnerable to pseudorange multipath effects and high ionospheric storms. In this paper, we propose a robust algorithm to detect and repair dual-frequency cycle slip for the network-based real-time kinematic (RTK) system which generates high-precision corrections for users. Two independent and complementary carrier-phase combinations, called the ionospheric negative and positive combinations in this paper, are employed for avoiding insensitive pairs. In addition, they are treated as second-order time differences to reduce the impact of ionospheric delay even under severe ionospheric storm. We verified that the actual error distributions of these monitoring values can be sufficiently bounded by the normal Gaussian distribution. Consequently, we demonstrated that the proposed method ensures high-integrity performance with a maximum probability of missed detection of 7.5 × 10−9 under a desired false-alarm probability of 10−5. Furthermore, we introduce a LAMBDA-based cycle slip compensation method, which has a failure rate of 1.4 × 10−8. Through an algorithm verification test using data collected under a severe ionospheric storm, we confirmed that artificially inserted cycle slips are successfully detected and compensated for. Thus, the proposed method is confirmed to be effective for handling dual-frequency cycle slips of the network RTK system.

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Real-time triple-frequency cycle slip detection and repair method under ionospheric disturbance validated with BDS data

Cited by 19 publications

References 15 publications

An Improved QZSS Satellite Clock Offsets Prediction Based on the Extreme Learning Machine Method

An Improved QZSS Satellite Clock Offsets Prediction Based on the Extreme Learning Machine Method

Real-Time Triple-Frequency Cycle Slip Detection and Repair Algorithm Based on the Optimal Fixing Probability

A New Algorithm for High-Integrity Detection and Compensation of Dual-Frequency Cycle Slip under Severe Ionospheric Storm Conditions

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