BDS satellite-induced code multipath: Mitigation and assessment in new-generation IOV satellites

Lei, Wenying; Wu, Guoqiang; Tao, Xiaoxia; Bian, Lang; Wang, X.L.

doi:10.1016/j.asr.2017.05.022

Cited by 19 publications

(11 citation statements)

References 14 publications

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“…The unique constellation design of BeiDou (GEO + IGSO + MEO) makes it more difficult to mitigate multipath effects compared to GPS (MEO only). The multipath issue of BeiDou signals has been intensively investigated recently [63][64][65][66][67][68]. It is expected that the algorithms for modeling multipath effects on BeiDou observations will be improved in the near future.…”

Section: Appl Sci 2019 9 X For Peer Reviewmentioning

confidence: 99%

Detection and Monitoring of Tunneling-Induced Riverbed Deformation Using GPS and BeiDou: A Case Study

et al. 2019

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Shield tunneling under rivers often requires monitoring riverbed deformations in near real-time. However, it is challenging to measure riverbed deformation with conventional survey techniques. This study introduces a comprehensive method that uses the Global Positioning System (GPS) of the USA and the BeiDou navigation satellite system (BeiDou) of China to monitor riverbed deformation during the construction of twin tunnels beneath the Hutuo River in Shijiazhuang, China. A semi-permanent GPS network with one base station outside the river and six rover stations within the river was established for conducting near real-time and long-term monitoring. The distances between the base and the rover antennas are within two kilometers. The network was continuously operating for eight months from April to December 2018. The method is comprised of three components: (1) Monitoring the stability of the base station using precise point positioning (PPP) method, a stable regional reference frame, and a seasonal ground deformation model; (2) monitoring the relative positions of rover stations using the carrier-phase double-difference (DD) positioning method in near real-time; and (3) detecting abrupt and gradual displacements at both base and rover stations using an automated change point detection algorithm. The method is able to detect abrupt positional-changes as minor as five millimeters in near real-time and gradual positional-changes at a couple of millimeters per day within a week. The method has the flexibility of concurrent processing different GPS and BeiDou data sessions (e.g., every 15 minutes, 30 minutes, one hour, one day) for diffident monitoring purposes. This study indicates that BeiDou observations can also achieve few-millimeter-accuracy for measuring displacements. Parallel processing GPS and BeiDou observations can improve the reliability of near real-time structural deformation monitoring and minimize false alerts. The method introduced in this article can be applied to other urban areas for near real-time and long-term structural health monitoring.

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Section: Appl Sci 2019 9 X For Peer Reviewmentioning

confidence: 99%

Detection and Monitoring of Tunneling-Induced Riverbed Deformation Using GPS and BeiDou: A Case Study

et al. 2019

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“…At the satellite end, the inner reflection signals depend on the bore-sight angles. Consequently, the elevation-dependent multipath errors can be observed at the user end [6]. Figure 1 shows the principle of multipath.…”

Section: Introductionmentioning

confidence: 99%

An Improved BDS Satellite-Induced Code Bias Correction Model Considering the Consistency of Multipath Combinations

Pan

Guo

2018

Remote Sensing

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The satellite-induced systematic biases were identified to exist in the code observations from BeiDou navigation satellite system (BDS) satellites using multipath (MP) combinations. The current correction model for satellite-induced code bias (SICB) does not take into account the consistency of MP combinations, which limits the accuracy of the developed model. Both the cycle slips and different tracking of a satellite at different stations can affect the absolute values of MP combinations, although the variations remain unchanged. An improved SICB piecewise linear correction model as a function of elevations is proposed. We estimate the model parameters for each frequency and for each satellite. The single-difference of MP combinations in the domain of elevation angles is carried out to remove the unknown ambiguities and stable hardware delays so that the SICB modeling is free of the effects of MP combination inconsistency. In addition, a denser elevation node separation of 1°, rather than the 10° usually employed by the traditional model, is used to describe the more precise SICB variations. The SICB corrections show significant differences among orbit types and frequency bands. The SICB variations have much less effect on Inclined Geosynchronous Orbit (IGSO) satellites than on Medium Earth Orbit (MEO) satellites for the regional BDS (BDS-2). The B1 signal has the largest SICB corrections, which can be up to 0.9 m close to zenith for BDS-2 MEO satellites, and the B2 signal follows. After adding the SICB corrections to the code observations, the elevation-dependent code biases vanish, and we can obtain improved code observations. After applying the improved SICB correction model, the root mean square (RMS) values of MP combination time series are reduced by 7%, 6% and 2%, and 18%, 14% and 5% on the B1, B2 and B3 frequencies for the BDS-2 IGSO and MEO satellites, respectively. For comparison, we also establish the traditional SICB correction model. With the traditional SICB correction model, the corresponding RMS MP combinations are smaller than those of uncorrected MP series, but slightly larger than those of corrected MP series using the improved SICB correction model. To validate the effectiveness and correctness of our proposed model, single-frequency precise point positioning (PPP) processing with BDS-2 MEO and IGSO satellites is conducted. An accuracy improvement of 24%, 19% and 89%, and 7%, 7% and 6% for the single-frequency PPP applying the improved SICB corrections over the case without SICB corrections and the case using the traditional SICB corrections in east, north and vertical directions is achieved, respectively. Although only centimeter-level SICB variations could be observed for the two legacy signals B1 and B3 and the three new navigation signals B1C, B2a and B2b transmitted by the satellites of global BDS demonstration system (BDS-3S), we still establish an effective SICB correction model on the B1 and B3 frequencies for BDS-3S IGSO satellites, and the RMS MP combinations are reduced by 1–4% after applying the improved SICB corrections.

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“…It is noted that the BDS satellite-induced code multipath effects were corrected for inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites, according to Wanninger and Beer [39], while geostationary orbit (GEO) satellites were excluded from the processing. The third-generation BDS satellites, which were no longer affected by such effects [49], were also excluded due to no public data. Throughout the processing, MGEX precise products provided by Deutsches GeoForschungsZentrum (GFZ) [50] were used.…”

Section: Data and Processing Strategymentioning

confidence: 99%

A Unified Model for Multi-Frequency PPP Ambiguity Resolution and Test Results with Galileo and BeiDou Triple-Frequency Observations

et al. 2019

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With the modernization of Global Navigation Satellite System (GNSS), triple- or multi-frequency signals have become available from more and more GNSS satellites. The additional signals are expected to enhance the performance of precise point positioning (PPP) with ambiguity resolution (AR). To deal with the additional signals, we propose a unified modeling strategy for multi-frequency PPP AR based on raw uncombined observations. Based on the unified model, the fractional cycle biases (FCBs) generated from multi-frequency observations can be flexibly used, such as for dual- or triple- frequency PPP AR. Its efficiency is verified with Galileo and BeiDou triple-frequency observations collected from globally distributed MGEX stations. The estimated FCB are assessed with respect to residual distributions and standard deviations. The obtained results indicate good consistency between the input float ambiguities and the generated FCBs. To assess the performance of the triple-frequency PPP AR, 11 days of MGEX data are processed in three-hour sessions. The positional biases in the ambiguity-fixed solutions are significantly reduced compared with the float solutions. The improvements are 49.2%, 38.3%, and 29.6%, respectively, in east/north/up components for positioning with BDS, while the corresponding improvements are 60.0%, 29.0%, and 21.1% for positioning with Galileo. These results confirm the efficiency of the proposed approach, and that the triple-frequency PPP AR can bring an obvious benefit to the ambiguity-float PPP solution.

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BDS satellite-induced code multipath: Mitigation and assessment in new-generation IOV satellites

Cited by 19 publications

References 14 publications

Detection and Monitoring of Tunneling-Induced Riverbed Deformation Using GPS and BeiDou: A Case Study

Detection and Monitoring of Tunneling-Induced Riverbed Deformation Using GPS and BeiDou: A Case Study

An Improved BDS Satellite-Induced Code Bias Correction Model Considering the Consistency of Multipath Combinations

A Unified Model for Multi-Frequency PPP Ambiguity Resolution and Test Results with Galileo and BeiDou Triple-Frequency Observations

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