scholarly journals NETWORK DGPS ACCURACY ASSESSMENT AT WEST COAST PENINSULAR MALAYSIA

2021 ◽  
Vol 6 (24) ◽  
pp. 301-311
Author(s):  
Muhammad Farid Mohd Yazair ◽  
Tajul Ariffin Musa ◽  
Wan Anom Wan Aris ◽  
Ivin Amri Musliman ◽  
Abdullah Hisam Omar

Maritime safety of navigation is essential for maritime activities especially when approaching the harbor. One of the important aspects in safety of navigation is positioning accuracy which the accuracy should less than 5 meters as recommended by IALA. Such accuracy can be provided by DGPS services. Nevertheless, the DGPS accuracy is bound to distance-dependent error due to uncorrelated errors between reference and rover station. By implementing the network-based DGPS technique, this issue however can be expected to be improved. This issue can be overcome by implementing the network-based DGPS technique to the positioning method. Hence, multiple of CORS in Peninsular Malaysia and Sumatran Indonesian were utilized to generate the network-based DGPS corrections based on LIM to cover the west coast of Peninsular Malaysia. The single point positioning, DGPS and network-based DGPS solutions were being compared with known points to determine the reliability of positioning in marine activities. The accuracy shows that the DGPS and network-based DGPS are better compared to single point positioning with below than 15m and 20m respectively. Meanwhile, the DGPS technique clearly had shown the distance-dependent error propagation in positioning. This paper presents on the accuracy and efficiency of network DGPS technique in reducing the distance-dependent error in DGPS positioning.

The variations of station coordinates deduced from Doppler observations with the use of a single point positioning method based on a precise ephemeris are estimated according to different models and softwares. An identical set of Doppler observations produces station coordinates whose coherence is generally better than 1 m. However, greater differences of 1.5 or 3 m can exceptionally be detected. Apart from the incoherence caused by the differences of models and criteria of data rejection, the reproducibility of Doppler results depends also, through the ephemeris used, on the epoch of measurements. From consecutive periods of 10 days of observations performed on the same site and analysed with the precise ephemeris computed by D. M. A., a set of station coordinates with a scatter of less than 1 m results. To keep the results near their true value it is also necessary to apply the model to a set of data having as characteristics a good balance between N-S and S-N passes, an approximate knowledge of the true meteorological parameters and at least 40 passes.


GPS Solutions ◽  
2013 ◽  
Vol 18 (2) ◽  
pp. 273-282 ◽  
Author(s):  
Jean-Philippe Montillet ◽  
Lukasz K. Bonenberg ◽  
Craig M. Hancock ◽  
Gethin W. Roberts

Positioning ◽  
2014 ◽  
Vol 05 (04) ◽  
pp. 107-114 ◽  
Author(s):  
Rock Santerre ◽  
Lin Pan ◽  
Changsheng Cai ◽  
Jianjun Zhu

2007 ◽  
Vol 42 (3) ◽  
pp. 149-153
Author(s):  
A. Farah

Code Single Point Positioning Using Nominal Gnss Constellations (Future Perception) Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry, science, military, transportation and recreation & sports. Two systems are currently in operation namely GPS (the USA Global Positioning System) and GLONASS (the Russian GLObal NAvigation Satellite System), and a third is planned, the European satellite navigation system GALILEO. The potential performance improvements achievable through combining these systems could be significant and expectations are high. The need is inevitable to explore the future of positioning from different nominal constellations. In this research paper, Bernese 5.0 software could be modified to simulate and process GNSS observations from three different constellations (GPS, Glonass and Galileo) using different combinations. This study presents results of code single point positioning for five stations using the three constellations and different combinations.


Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6197
Author(s):  
Kai Liu ◽  
Xiye Guo ◽  
Jun Yang ◽  
Xiaoyu Li ◽  
Changshui Liu ◽  
...  

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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