Correction of fractional cycle bias of pseudolite system for user integer ambiguity resolution

Li, Kai; Yang, Jun; Guo, Xiaofeng; Zhou, Yongbin; Liu, Changshui

doi:10.1007/s10291-018-0771-5

Cited by 13 publications

(5 citation statements)

References 17 publications

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“…The impact of clock offset on both single-point positioning [107] and differential positioning [108] is significant. Clock discrepancies from ground-based transmitters can lead to asynchronous timing problems [109] and hinder attempts to fix integer ambiguity [110].…”

Section: Clock Synchronizationmentioning

confidence: 99%

“…For example, with the Locata system, a master transceiver synchronizes its slave transceivers over a wireless network [69]. Based on this approach, bidirectional time synchronization between multiple pseudolites over a network cable or wirelessly can be achieved [107,113].…”

Section: Clock Synchronizationmentioning

confidence: 99%

“…Time delay fluctuations can disrupt the integer properties of the carrier phase. A fractional cycle deviation correction method [107] was proposed for the case where the ambiguity of observations in pseudolites is usually estimated as a floatingpoint value. This method is based on bidirectional time synchronization and corrects its own bias by pseudolite network estimation.…”

Section: Clock Synchronizationmentioning

confidence: 99%

See 2 more Smart Citations

Pseudolites to Support Location Services in Smart Cities: Review and Prospects

Liu,

Wang

et al. 2023

Smart Cities

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The location service is an important part of the smart city. A unified location service for outdoor and indoor/overground and underground activity will assist the construction of smart cities. However, with different coordinate systems and data formats, it is difficult to unify various positioning technologies on the same basis. Global navigation satellite system (GNSS)-based positioning is the only way to provide absolute location under the Earth-centered, Earth-fixed coordinate system (ECEF). Increasing indoor and underground human activity places significant demand on location-based services but no GNSS signals are available there. Fortunately, a type of satellite that is indoors, known as pseudolite, can transmit GNSS-like ranging signals. Users can obtain their position by receiving ranging signals and their resection without adding or switching other sensors when they go from outdoors to indoors. To complete the outreach of the GNSS indoors and underground to support the smart city, how to adapt the pseudolite design and unify coordinate frames for linking to the GNSS remain to be determined. In this regard, we provide an overview of the history of the research and application of pseudolites, the research progress from both the system side and the user side, and the plans for pseudolite-based location services in smart cities.

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Section: Clock Synchronizationmentioning

confidence: 99%

Section: Clock Synchronizationmentioning

confidence: 99%

Section: Clock Synchronizationmentioning

confidence: 99%

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Pseudolites to Support Location Services in Smart Cities: Review and Prospects

Liu,

Wang

et al. 2023

Smart Cities

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“…As nuisance fractional cycle bias parameter owing to the clock offset between two pseudolites δt ij = δt i − δt j can be eliminated by the synchronized pseudolite system in the transmitter end, SD carrier phase ambiguity is retrieved to be integer in nature [12].…”

Section: Pseudolite Measurement Modelmentioning

confidence: 99%

“…Some single-differenced (SD) FCBs estimation method and undifferenced FCBs estimation method are developed for recovering the integer property of the ambiguity parameter [10,11]. Learning from the idea of the GNSS PPP, an FCB correction method is proposed to recover the integer nature of single-difference ambiguities for the synchronized pseudolite system, and the experiment demonstrates the capability of real-time single-point positioning with centimeter or even millimeter positioning accuracy [12].…”

Section: Introductionmentioning

confidence: 99%

Kinematic ME-MAFA for Pseudolite Carrier-Phase Ambiguity Resolution in Precise Single-Point Positioning

Guo

Yang

et al. 2020

Sensors

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Precise single-point positioning using carrier-phase measurements can be provided by the synchronized pseudolite system. The primary task of carrier phase positioning is ambiguity resolution (AR) with rapidity and reliability. As the pseudolite system is usually operated in the dense multipath environment, cycle slips may lead the conventional least-squares ambiguity decorrelation adjustment (LAMBDA) method to incorrect AR. A new AR method based on the idea of the modified ambiguity function approach (MAFA), which is insensitive to the cycle slips, is studied in this paper. To improve the model strength of the MAFA and to eliminate the influence of constant multipath biases on the time-average model in static mode, the kinematic multi-epoch MAFA (kinematic ME-MAFA) algorithm is proposed. A heuristic method for predicting the ‘float position’ corresponding to every Voronoi cell of the next epoch, making use of Doppler-based velocity information, is implemented to improve the computational efficiency. If the success rate is very close to 1, it is possible to guarantee reliable centimeter-level accuracy positioning without further ambiguity validation. Therefore, a computing method of the success rate for the kinematic ME-MAFA is proposed. Both the numerical simulations and the kinematic experiment demonstrate the feasibility of the new AR algorithm according to its accuracy and reliability. The accuracy of the horizontal positioning solution is better than 1.7 centimeters in our pseudolite system.

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