scholarly journals Optimal Carrier-Phase Integer Combinations for Modernized Triple-Frequency BDS in Precise Point Positioning

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 177449-177459 ◽  
Author(s):  
Honglei Qin ◽  
Peng Liu ◽  
Jiaqing Qu ◽  
Li Cong
Keyword(s):  
Carrier Phase ◽  
Precise Point Positioning ◽  
Triple Frequency ◽  
Point Positioning

scholarly journals Precise point positioning with decimetre accuracy using wide-lane ambiguities and triple-frequency GNSS data

2020 ◽  
Vol 14 (3) ◽  
pp. 263-284
Author(s):  
Manoj Deo ◽  
Ahmed El-Mowafy
Keyword(s):  
Linear Combination ◽  
Carrier Phase ◽  
Precise Point Positioning ◽  
Low Noise ◽  
Positioning Accuracy ◽  
The Third ◽  
Triple Frequency ◽  
Wide Lane ◽  
Point Positioning ◽  
Gnss Data

AbstractThis paper proposes precise point positioning (PPP) methods that offer an accuracy of a few decimetres (dm) with triple frequency GNSS data. Firstly, an enhanced triple frequency linear combination is presented for rapid fixing of the extra wide-lane (EWL) and wide-lane (WL) ambiguities for GPS, Beidou-2 and Galileo. This has improved performance compared to the Melbourne-Wübbena (MW) linear combination, and has 6.7 % lower measurement noise for the GPS L1/L2 signals, 12.7 % for L1/L5 and 0.7 % for L2/L5. Analysis with tested data showed a 5–6 % reduction in time required to fix the {N_{21}} and {N_{51}} ambiguities.Once the EWL/WL ambiguities are fixed with the proposed linear combinations, three methods are presented that aim to provide positioning accuracy of a few dm. In the first approach, the three EWL/WL ambiguities in their respective phase equations are used to derive a low-noise ionosphere-free (IF) linear combination. The second method uses a low noise IF combination with two carrier-phase EWL/WL equations and a single pseudorange measurement. The third method uses a low noise IF combination with a single carrier phase EWL equation and two pseudorange measurements. These proposed methods can provide dm level positioning accuracy if carrier phase measurements with mm precision is tracked by the receiver. When comparing these combinations with a combination proposed in [22], it is found that superior performance is achieved with the third method when carrier phase noise is >5–6 mm for GPS and Beidou-2 and >2–3 mm for Galileo. This model only requires the EWL ambiguity to be fixed which typically takes just one epoch of data. Thus, the user achieves instant decimetre level PPP accuracy.

scholarly journals Triple-Frequency GPS Precise Point Positioning Ambiguity Resolution Using Dual-Frequency Based IGS Precise Clock Products

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Fei Liu ◽  
Yang Gao
Keyword(s):  
Ambiguity Resolution ◽  
Carrier Phase ◽  
Precise Point Positioning ◽  
Free Carrier ◽  
Convergence Time ◽  
Dual Frequency ◽  
Phase Measurements ◽  
Triple Frequency ◽  
Wide Lane ◽  
Point Positioning

With the availability of the third civil signal in the Global Positioning System, triple-frequency Precise Point Positioning ambiguity resolution methods have drawn increasing attention due to significantly reduced convergence time. However, the corresponding triple-frequency based precise clock products are not widely available and adopted by applications. Currently, most precise products are generated based on ionosphere-free combination of dual-frequency L1/L2 signals, which however are not consistent with the triple-frequency ionosphere-free carrier-phase measurements, resulting in inaccurate positioning and unstable float ambiguities. In this study, a GPS triple-frequency PPP ambiguity resolution method is developed using the widely used dual-frequency based clock products. In this method, the interfrequency clock biases between the triple-frequency and dual-frequency ionosphere-free carrier-phase measurements are first estimated and then applied to triple-frequency ionosphere-free carrier-phase measurements to obtain stable float ambiguities. After this, the wide-lane L2/L5 and wide-lane L1/L2 integer property of ambiguities are recovered by estimating the satellite fractional cycle biases. A test using a sparse network is conducted to verify the effectiveness of the method. The results show that the ambiguity resolution can be achieved in minutes even tens of seconds and the positioning accuracy is in decimeter level.

scholarly journals Real-time GNSS precise point positioning for low-cost smart devices

GPS Solutions ◽  
2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Liang Wang ◽  
Zishen Li ◽  
Ningbo Wang ◽  
Zhiyu Wang
Keyword(s):  
Carrier Phase ◽  
Measurement Errors ◽  
Precise Point Positioning ◽  
Low Cost ◽  
Smart Devices ◽  
Dual Frequency ◽  
Static Mode ◽  
Phase Measurements ◽  
Positioning Errors ◽  
Point Positioning

AbstractGlobal Navigation Satellite System raw measurements from Android smart devices make accurate positioning possible with advanced techniques, e.g., precise point positioning (PPP). To achieve the sub-meter-level positioning accuracy with low-cost smart devices, the PPP algorithm developed for geodetic receivers is adapted and an approach named Smart-PPP is proposed in this contribution. In Smart-PPP, the uncombined PPP model is applied for the unified processing of single- and dual-frequency measurements from tracked satellites. The receiver clock terms are parameterized independently for the code and carrier phase measurements of each tracking signal for handling the inconsistency between the code and carrier phases measured by smart devices. The ionospheric pseudo-observations are adopted to provide absolute constraints on the estimation of slant ionospheric delays and to strengthen the uncombined PPP model. A modified stochastic model is employed to weight code and carrier phase measurements by considering the high correlation between the measurement errors and the signal strengths for smart devices. Additionally, an application software based on the Android platform is developed for realizing Smart-PPP in smart devices. The positioning performance of Smart-PPP is validated in both static and kinematic cases. Results show that the positioning errors of Smart-PPP solutions can converge to below 1.0 m within a few minutes in static mode and the converged solutions can achieve an accuracy of about 0.2 m of root mean square (RMS) both for the east, north and up components. For the kinematic test, the RMS values of Smart-PPP positioning errors are 0.65, 0.54 and 1.09 m in the east, north and up components, respectively. Static and kinematic tests both show that the Smart-PPP solutions outperform the internal results provided by the experimental smart devices.

scholarly journals GPS + Galileo + BeiDou precise point positioning with triple-frequency ambiguity resolution

GPS Solutions ◽  
2020 ◽  
Vol 24 (3) ◽  
Author(s):  
Pan Li ◽  
Xinyuan Jiang ◽  
Xiaohong Zhang ◽  
Maorong Ge ◽  
Harald Schuh
Keyword(s):  
Ambiguity Resolution ◽  
Precise Point Positioning ◽  
Triple Frequency ◽  
Point Positioning

scholarly journals Precise Point Positioning for TAI Computation

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Gérard Petit ◽  
Zhiheng Jiang
Keyword(s):  
Time Scale ◽  
Carrier Phase ◽  
Precise Point Positioning ◽  
Dual Frequency ◽  
Time Transfer ◽  
Short Term ◽  
Reference Time ◽  
Local Clock ◽  
Point Positioning ◽  
Simple Difference

We discuss the use of some new time transfer techniques for computing TAI time links. Precise point positioning (PPP) uses GPS dual frequency carrier phase and code measurements to compute the link between a local clock and a reference time scale with the precision of the carrier phase and the accuracy of the code. The time link between any two stations can then be computed by a simple difference. We show that this technique is well adapted and has better short-term stability than other techniques used in TAI. We present a method of combining PPP and two-way time transfer that takes advantage of the qualities of each technique, and shows that it would bring significant improvement to TAI links.

Modeling of multi-sensor tightly aided BDS triple-frequency precise point positioning and initial assessments

2020 ◽  
Vol 55 ◽  
pp. 184-198 ◽  
Author(s):  
Zhouzheng Gao ◽  
Maorong Ge ◽  
You Li ◽  
Yuanjin Pan ◽  
Qijin Chen ◽  
...  
Keyword(s):  
Precise Point Positioning ◽  
Triple Frequency ◽  
Point Positioning

Recent Developments in Precise Point Positioning

GEOMATICA ◽  
2012 ◽  
Vol 66 (2) ◽  
pp. 103-111 ◽  
Author(s):  
S. Bisnath ◽  
P. Collins
Keyword(s):  
Real Time ◽  
Ambiguity Resolution ◽  
Carrier Phase ◽  
Precise Point Positioning ◽  
Solution Convergence ◽  
Similar Information ◽  
Recent Developments ◽  
Significant Step ◽  
Point Positioning ◽  
New Processing

In standard Precise Point Positioning (PPP), the carrier phase ambiguities are estimated as real-valued constants, so that the carrier-phases can provide similar information as the pseudoranges. As a consequence, it can take tens of minutes to several hours for the ambiguities to converge to suitably precise values. Recently, new processing methods have been identified that permit the ambiguities to be estimated more appropriately as integer-valued constants, as they are in relative Real-Time Kinematic (RTK) positioning. Under these conditions, standard ambiguity resolution techniques can be applied to strengthen the PPP solution. The result can be a greatly reduced solution convergence and re-convergence period, representing a significant step toward improving the performance of PPP with respect to that of RTK processing. This paper describes the underlying principles of the method, why the enhancements work, and presents some results.

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