A triple-frequency cycle slip detection and correction method based on modified HMW combinations applied on GPS and BDS

Zhao, Dongsheng; Roberts, Gethin Wyn; Hancock, Craig M.; Lau, Lawrence; Bai, Ruibin

doi:10.1007/s10291-018-0817-8

Cited by 25 publications

(39 citation statements)

References 21 publications

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“…where denotes the time differenced operation between two consecutive epochs; N is the ambiguity; the subscripts indicate the frequencies; (i, j, k) indicates the combined signal with the coefficients i, j and k for the frequencies [23]; λ is the wavelength; P and Φ represent the code measurement and the phase measurement in units of length respectively;Φ (0,1,−1) is the combined phase measurement (0, 1, −1) where cycle slips have been corrected; a, b, c and d are the coefficients. Compared to the traditional HMW combination, this modified HMW combination can have a better manipulation of the ionospheric bias and measurement noise [13]. The difficulty of this modified HMW combination is the determination of the optimally combined signals, which should be able to provide the most precise time-differenced ambiguities.…”

Section: Selection Of Optimally Combined Signalsmentioning

confidence: 99%

“…The third constrained condition is to minimize the effect of the measurement noise on N (i,j,k) . Based on the empirical assumptions for the phase and code measurement noise given in Zhao et al [13], the effect of the measurement noise on N (i,j,k) can be calculated as follows:…”

Section: Selection Of Optimally Combined Signalsmentioning

confidence: 99%

“…µ 2 is the phase noise factor. Determining the optimally combined signals in Equation (1) with the previous three constraints is an equality constrained optimization problem, which can be solved using the method proposed by Zhao et al [13].…”

Section: Selection Of Optimally Combined Signalsmentioning

confidence: 99%

“…When high ionospheric activity occurs, the sudden changes of the noise level and ionospheric delay can be problematic to the methods developed based on the legacy signals, e.g., high-order phase differencing [9], Doppler integration [10], and some of the latest proposed methods, such as Huang et al [11], de Lacy [12] and Zhao et al [13], as these methods are raised on the basis of the assumption that the ionospheric delay varies smoothly over time. More literature on cycle slip detection is available in Section 2.…”

Section: Introductionmentioning

confidence: 99%

“…More literature on cycle slip detection is available in Section 2. Although the method proposed by Zhao et al [13] cannot provide a robust detection performance during high ionospheric activities, one of the proposed combined signals (4, 0, −5) in the modified Hatch-Melbourne-Wübbena (HMW) combinations can maintain a high precise detection value even when it is biased by the ionosphere, revealing the potential to expand the application of the modified HMW combination in the scenario of high ionospheric activities. Inspired by this, this paper proposes newly constrained conditions to select the optimally combined signals of the modified HMW combinations to detect cycle slips in the observations collected by geodetic receivers during high ionospheric activities, as shown in Section 3.…”

Section: Introductionmentioning

confidence: 99%

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Cycle Slip Detection during High Ionospheric Activities Based on Combined Triple-Frequency GNSS Signals

et al. 2019

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The current cycle slip detection methods of Global Navigation Satellite System (GNSS) were mostly proposed on the basis of assuming the ionospheric delay varying smoothly over time. However, these methods can be invalid during active ionospheric periods, e.g., high Kp index value and scintillations, due to the significant increase of the ionospheric delay. In order to detect cycle slips during high ionospheric activities successfully, this paper proposes a method based on two modified Hatch–Melbourne–Wübbena combinations. The measurement noise in the Hatch–Melbourne–Wübbena combination is minimized by employing the optimally selected combined signals, while the ionospheric delay is detrended using a smoothing technique. The difference between the time-differenced ambiguity of the combined signal and this estimated ionospheric trend is adopted as the detection value, which can be free from ionospheric effect and hold the high precision of the combined signal. Five threshold determination methods are proposed and compared to decide the cycle slip from the magnitude aspect. This proposed method is tested with triple-frequency Global Navigation Satellite System observations collected under high ionospheric activities. Results show that the proposed method can correctly detect and fix cycle slips under disturbed ionosphere.

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Section: Selection Of Optimally Combined Signalsmentioning

confidence: 99%

Section: Selection Of Optimally Combined Signalsmentioning

confidence: 99%

Section: Selection Of Optimally Combined Signalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cycle Slip Detection during High Ionospheric Activities Based on Combined Triple-Frequency GNSS Signals

et al. 2019

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GNSS Data Processing

Ogaja¹

2022

Introduction to GNSS Geodesy

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Cycle slip detection and repair method towards multi-frequency BDS-3/INS tightly coupled integration in kinematic surveying

Xiao,

Zhu,

Zhang

et al. 2024

J Geod

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Carrier phase integer ambiguities must be determined for BDS-3/inertial navigation system (INS) tightly coupled (TC) integration to achieve centimetre-level positioning accuracy. However, cycle slip breaks the consistency of the integer ambiguities. Conventional multi-frequency cycle slip methods use the pseudorange; thus, requiring improvement when applied to kinematic situations. Furthermore, a concise and nonprior information-dependent model is crucial for real-time processing. In this study, an inertial-aided BDS-3 cycle slip detection and repair (I-CDR) method was developed. First, a BDS-3/INS TC model with I-CDR was created. The ionospheric delays were modelled as part of the TC states; therefore, they could be estimated and eliminated. Investigations were conducted on the effects of carrier phase noise, residual ionosphere delay, and INS-predicted position error on combined cycle slip detection (CCD) accuracy. The optimal CCDs under various frequency available configurations were determined. The effectiveness of I-CDR was demonstrated using land vehicle test data. The false alarm ratio was less than 1.0%, and the missed detection ratio was almost zero even in situations with challenging abundant 1-cycle slips in random epochs. Furthermore, the right determination ratio reached 100%. In addition, BDS-3 signal loss-recovery cases were simulated, and all cycle slips for all satellites could be repaired within 40s. I-CDR exhibits outstanding cycle slip detection and repair performance for dense 1-cycle slip and signal loss-recovery cases, demonstrating its suitability for BDS-3/INS TC integration.

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A triple-frequency cycle slip detection and correction method based on modified HMW combinations applied on GPS and BDS

Cited by 25 publications

References 21 publications

Cycle Slip Detection during High Ionospheric Activities Based on Combined Triple-Frequency GNSS Signals

Cycle Slip Detection during High Ionospheric Activities Based on Combined Triple-Frequency GNSS Signals

GNSS Data Processing

Cycle slip detection and repair method towards multi-frequency BDS-3/INS tightly coupled integration in kinematic surveying

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