Three-carrier ambiguity resolution using the modified TCAR method

Zhao, Qile; Dai, Zhiqiang; Hu, Zhigang; Sun, Binzi; Shi, Chuang; Liu, Jingnan

doi:10.1007/s10291-014-0421-5

Cited by 45 publications

(36 citation statements)

References 9 publications

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“…In addition, Table 1 also details the specific implementation of dynamic models for state vector and stochastic models for measurements [9]. The code and phase observation precision for GPS are usually set to 0.3 and 0.002 m, respectively [31,32]. Compared with GPS, BDS satellite orbit and clock are at a relatively lower accuracy and BDS measurements exhibit relatively higher noise level [9,17].…”

Section: Triple-frequency Precise Point Positioning Modelmentioning

confidence: 99%

Considering Inter-Frequency Clock Bias for BDS Triple-Frequency Precise Point Positioning

Pan

Zhang

et al. 2017

Remote Sensing

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Abstract:The joint use of multi-frequency signals brings new prospects for precise positioning and has become a trend in Global Navigation Satellite System (GNSS) development. However, a new type of inter-frequency clock bias (IFCB), namely the difference between satellite clocks computed with different ionospheric-free carrier phase combinations, was noticed. Consequently, the B1/B3 precise point positioning (PPP) cannot directly use the current B1/B2 clock products. Datasets from 35 globally distributed stations are employed to investigate the IFCB. For new generation BeiDou Navigation Satellite System (BDS) satellites, namely BDS-3 satellites, the IFCB between B1/B2a and B1/B3 satellite clocks, between B1/B2b and B1/B3 satellite clocks, between B1C/B2a and B1C/B3 satellite clocks, and between B1C/B2b and B1C/B3 satellite clocks is analyzed, and no significant IFCB variations can be observed. The IFCB between B1/B2 and B1/B3 satellite clocks for BDS-2 satellites varies with time, and the IFCB variations are generally confined to peak amplitudes of about 5 cm. The IFCB of BDS-2 satellites exhibits periodic signal, and the accuracy of prediction for IFCB, namely the root mean square (RMS) statistic of the difference between predicted and estimated IFCB values, is 1.2 cm. A triple-frequency PPP model with consideration of IFCB is developed. Compared with B1/B2-based PPP, the positioning accuracy of triple-frequency PPP with BDS-2 satellites can be improved by 12%, 25% and 10% in east, north and vertical directions, respectively.

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Section: Triple-frequency Precise Point Positioning Modelmentioning

confidence: 99%

Considering Inter-Frequency Clock Bias for BDS Triple-Frequency Precise Point Positioning

Pan

Zhang

et al. 2017

Remote Sensing

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“…First, two widely-used WL combinations φ (1,−1,0) and φ (1,0,−1) are constructed [20,23], and then the ambiguity link between EWL and WL ambiguities can be formed as…”

Section: Wl Ambiguity Resolutionmentioning

confidence: 99%

“…The ionosphere-free combination ensures the absence of ionospheric bias, but the combined observation noise is largely amplified, which will worsen ambiguity resolution performance [18,19]. Therefore, a moving average method has to be used to restrict the effect of combined observation noise [7,13,17,20,21]. Furthermore, the ionosphere-reduced combination can also be applied because it is in essence a trade-off between the ionospheric effect reduction and observation variance restriction.…”

Section: Introductionmentioning

confidence: 99%

Improving the Triple-Carrier Ambiguity Resolution with a New Ionosphere-Free and Variance-Restricted Method

Chun

Zhao

et al. 2017

Remote Sensing

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Abstract:The ionospheric bias and the combined observation noise are two crucial factors affecting the reliability of the triple-carrier ambiguity resolution (TCAR). In order to obtain a better reliability of TCAR, a new ionosphere-free and variance-restricted TCAR method is proposed through exploring the ambiguity link between each step of TCAR. The method constructs an ionosphere-free combination and simultaneously restricts the combined observation noise with respect to the wavelength to a sufficiently low level for each step of TCAR. The performance of the proposed method is tested by the datasets from the BeiDou navigation satellite system (BDS), with the baseline varying from 7.7 km to 68.8 km. Comparing with the state-of-the-art TCAR methods, the experimental results indicate that the proposed method can obtain a better performance of ambiguity resolution, even though the double-differenced ionospheric delay increases up to 72.4 cm at the baseline of 68.8 km.

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“…In the triple-frequency case, the three pseudoranges can be combined together to obtain the optimal ionosphere-free pseudorange. This can be determined by the following equations Zhao et al, 2015):…”

Section: S I N G L E -E P O C H B D S Nav I G Atmentioning

confidence: 99%

Single-Epoch Navigation Performance with Real BDS Triple-Frequency Pseudorange and EWL/WL Observations

Gao

Pan

2016

J. Navigation

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Triple-frequency signals of China's BeiDou navigation satellite system (BDS) are now accessible in the Asia-Pacific region. It is well understood that the third frequency signal will improve the navigation performance. Some literatures have described several navigation methods by using triple-frequency signals, and evaluated the performance. However the experiments were mostly implemented on simulated or semi-simulated observations. In this paper we investigate the navigation performance using real BDS triple-frequency observations. Apart from the pseudorange observations, carrier observations are also used, since the extra-wide-lane and wide-lane ambiguities can be reliably resolved with a single epoch. Several single-epoch navigation methods using BDS triple-frequency observations are described and the corresponding navigation accuracy and reliability are assessed. Results show that P3 has the highest accuracy among the three pseudorange observations. For carriers, the wide-lane and extra-wide-lane observations can be used to obtain much higher navigation precision compared with pseudorange observations. Besides, the two ambiguity-fixed extra-wide-lane and wide-lane observations can also be combined to ionosphere-free form, which can still obtain sub-decimetre and decimetre navigation accuracy in horizontal and vertical directions respectively. K E Y WO R D S 1. BeiDou navigation satellite system (BDS).2. Single-epoch navigation.3. Triple-frequency observations. 4. Positioning reliability.

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Three-carrier ambiguity resolution using the modified TCAR method

Cited by 45 publications

References 9 publications

Considering Inter-Frequency Clock Bias for BDS Triple-Frequency Precise Point Positioning

Considering Inter-Frequency Clock Bias for BDS Triple-Frequency Precise Point Positioning

Improving the Triple-Carrier Ambiguity Resolution with a New Ionosphere-Free and Variance-Restricted Method

Single-Epoch Navigation Performance with Real BDS Triple-Frequency Pseudorange and EWL/WL Observations

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