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 A New GNSS Single-Epoch Ambiguity Resolution Method Based on Triple-Frequency Signals

2017 ◽  
Vol 6 (2) ◽  
pp. 46 ◽  
Author(s):  
Shengli Wang ◽  
Jian Deng ◽  
Xiushan Lu ◽  
Ziyuan Song ◽  
Ying Xu
Keyword(s):  
Ambiguity Resolution ◽  
Resolution Method ◽  
Triple Frequency ◽  
Single Epoch

An Improved Geometry-free Three Carrier Ambiguity Resolution Method for the BeiDou Navigation Satellite System

2016 ◽  
Vol 69 (6) ◽  
pp. 1393-1408 ◽  
Author(s):  
Xing Wang ◽  
Wenxiang Liu ◽  
Guangfu Sun
Keyword(s):  
Ambiguity Resolution ◽  
Carrier Phase ◽  
Success Probability ◽  
Satellite System ◽  
Observation Data ◽  
Short Baseline ◽  
Long Baseline ◽  
Triple Frequency ◽  
Wide Lane ◽  
Three Carrier Ambiguity Resolution

BeiDou satellites transmit triple-frequency signals, which bring substantial benefits to carrier phase Ambiguity Resolution (AR). The traditional geometry-free model Three-Carrier Ambiguity Resolution (TCAR) method looks for a suitable combination of carrier phase and code-range observables by searching and comparing in the integer range, which limits the AR success probability. By analysing the error characteristics of the BeiDou triple-frequency observables, we introduce a new procedure to select the optimal combination of carrier phase and code observables to resolve the resolution of Extra-Wide-Lane (EWL) and Wide-Lane (WL) ambiguity. We also investigate a geometry-free and ionosphere-eliminated method for AR of the Medium-Lane (ML) and Narrow-Lane (NL) observables. In order to evaluate the performance of the improved TCAR method, real BeiDou triple-frequency observation data for different baseline cases were collected and processed epoch-by-epoch. The results show that the improved geometry-free TCAR method increases the single epoch AR success probability by up to 90% for short baseline and 80% for long baseline. The A perfect (100%) AR success probability can also be effortlessly achieved by averaging the float ambiguities over just tens of epochs.

scholarly journals Estimating the Fractional Cycle Biases for GPS Triple-Frequency Precise Point Positioning with Ambiguity Resolution Based on IGS Ultra-Rapid Predicted Orbits

2021 ◽  
Vol 13 (16) ◽  
pp. 3164
Author(s):  
Lizhong Qu ◽  
Pu Zhang ◽  
Changfeng Jing ◽  
Mingyi Du ◽  
Jian Wang ◽  
...  
Keyword(s):  
Ambiguity Resolution ◽  
Precise Point Positioning ◽  
Triple Frequency ◽  
Wide Lane ◽  
Single Difference ◽  
Point Positioning ◽  
L5 Signal ◽  
New Generation ◽  
Orbit Errors ◽  
The Impact

We investigate the estimation of the fractional cycle biases (FCBs) for GPS triple-frequency uncombined precise point positioning (PPP) with ambiguity resolution (AR) based on the IGS ultra-rapid predicted (IGU) orbits. The impact of the IGU orbit errors on the performance of GPS triple-frequency PPP AR is also assessed. The extra-wide-lane (EWL), wide-lane (WL) and narrow-lane (NL) FCBs are generated with the single difference (SD) between satellites model using the global reference stations based on the IGU orbits. For comparison purposes, the EWL, WL and NL FCBs based on the IGS final precise (IGF) orbits are estimated. Each of the EWL, WL and NL FCBs based on IGF and IGU orbits are converted to the uncombined FCBs to implement the static and kinematic triple-frequency PPP AR. Due to the short wavelengths of NL ambiguities, the IGU orbit errors significantly impact the precision and stability of NL FCBs. An average STD of 0.033 cycles is achieved for the NL FCBs based on IGF orbits, while the value of the NL FCBs based on IGU orbits is 0.133 cycles. In contrast, the EWL and WL FCBs generated based on IGU orbits have comparable precision and stability to those generated based on IGF orbits. The use of IGU orbits results in an increased time-to-first-fix (TTFF) and lower fixing rates compared to the use of IGF orbits. Average TTFFs of 23.3 min (static) and 31.1 min (kinematic) and fixing rates of 98.1% (static) and 97.4% (kinematic) are achieved for the triple-frequency PPP AR based on IGF orbits. The average TTFFs increase to 27.0 min (static) and 37.9 min (kinematic) with fixing rates of 97.0% (static) and 96.3% (kinematic) based on the IGU orbits. The convergence times and positioning accuracy of PPP and PPP AR based on IGU orbits are slightly worse than those based on IGF orbits. Additionally, limited by the number of satellites transmitting three frequency signals, the introduction of the third frequency, L5, has a marginal impact on the performance of PPP and PPP AR. The GPS triple-frequency PPP AR performance is expected to improve with the deployment of new-generation satellites capable of transmitting the L5 signal.

scholarly journals Approaching Global Instantaneous Precise Positioning with the Dual- and Triple-Frequency Multi-GNSS Decoupled Clock Model

2021 ◽  
Vol 13 (18) ◽  
pp. 3768
Author(s):  
Nacer Naciri ◽  
Sunil Bisnath
Keyword(s):  
Ambiguity Resolution ◽  
Ar Model ◽  
Convergence Time ◽  
Dual Frequency ◽  
Clock Model ◽  
Precise Positioning ◽  
Triple Frequency ◽  
Positioning Technique ◽  
Carrier Phase Ambiguity ◽  
Decoupled Clock Model

Precise Point Positioning (PPP), as a global precise positioning technique, suffers from relatively long convergence times, hindering its ability to be the default precise positioning technique. Reducing the PPP convergence time is a must to reach global precise positions, and doing so in a few minutes to seconds can be achieved thanks to the additional frequencies that are being broadcast by the modernized GNSS constellations. Due to discrepancies in the number of signals broadcast by each satellite/constellation, it is necessary to have a model that can process a mix of signals, depending on availability, and perform ambiguity resolution (AR), a technique that proved necessary for rapid convergence. This manuscript does so by expanding the uncombined Decoupled Clock Model to process and fix ambiguities on up to three frequencies depending on availability for GPS, Galileo, and BeiDou. GLONASS is included as well, without carrier-phase ambiguity fixing. Results show the possibility of consistent quasi-instantaneous global precise positioning through an assessment of the algorithm on a network of global stations, as the 67th percentile solution converges below 10 cm horizontal error within 2 min, compared to 8 min with a triple-frequency solution, showing the importance of having a flexible PPP-AR model frequency-wise. In terms of individual datasets, 14% of datasets converge instantaneously when mixing dual- and triple-frequency measurements, compared to just 0.1% in that of dual-frequency mode without ambiguity resolution. Two kinematic car datasets were also processed, and it was shown that instantaneous centimetre-level positioning with a moving receiver is possible. These results are promising as they only rely on ultra-rapid global satellite products, allowing for instantaneous real-time precise positioning without the need for any local infrastructure or prior knowledge of the receiver’s environment.

scholarly journals Speeding up PPP ambiguity resolution using triple-frequency GPS/BeiDou/Galileo/QZSS data

2019 ◽  
Author(s):  
Jianghui Geng ◽  
Jiang Guo ◽  
Xiaolin Meng ◽  
Kefu Gao
Keyword(s):  
Ambiguity Resolution ◽  
Triple Frequency

scholarly journals A MEMS-IMU Assisted BDS Triple-Frequency Ambiguity Resolution Method in Complex Environments

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Junbing Cheng ◽  
Deng-ao Li ◽  
Jumin Zhao
Keyword(s):  
High Precision ◽  
Ambiguity Resolution ◽  
Noise Level ◽  
Measurement Unit ◽  
Navigation Satellite ◽  
Complex Environments ◽  
Precision Positioning ◽  
Triple Frequency ◽  
Total Noise ◽  
Mems Imu

Emerging technologies such as smart cities and unmanned vehicles all need Global Navigation Satellite Systems (GNSS) to provide high-precision positioning and navigation services. Fast and reliable carrier phase ambiguity resolution (AR) is a prerequisite for high-precision positioning. The poor satellite geometry and severe multipath effect caused by Beidou Navigation Satellite System (BDS) signal occlusion and reflection in complex environments will degrade the AR performance. In this contribution, a fast triple-frequency AR method combining Microelectromechanical System-Inertial Measurement Unit (MEMS-IMU) and BDS is proposed. First, the Extra-Wide Lane (EWL) ambiguity is fixed with the positioning parameters of MEMS-IMU instead of the pseudorange. Then, the phase noise variance of Narrow Lane (NL) observation is obtained from ambiguity-fixed EWL observation to reduce the total noise level of NL observation, and the NL ambiguity can be reliably fixed, and the BDS positioning result is obtained. Finally, the BDS positioning result is used as the posterior measurement of the extended Kalman filter to update the MEMS-IMU positioning parameters to form the coupling loop of MEMS-IMU and BDS. The data of urban road vehicle experiments were collected to verify the feasibility and effectiveness of the proposed algorithm. Results show that MEMS-IMU can speed up AR, and reduction of total noise level can significantly improve the reliability of AR.

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

2019 ◽  
Vol 11 (2) ◽  
pp. 116 ◽  
Author(s):  
Guorui Xiao ◽  
Pan Li ◽  
Yang Gao ◽  
Bernhard Heck
Keyword(s):  
Ambiguity Resolution ◽  
Satellite System ◽  
Unified Model ◽  
Test Results ◽  
Unified Modeling ◽  
Triple Frequency ◽  
Obvious Benefit ◽  
Modeling Strategy ◽  
Global Navigation Satellite ◽  
Globally Distributed

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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