An Investigation of GPS Satellite Clock Offsets Prediction with Different Update Intervals and Application to Real-Time PPP

2016 ◽  
Author(s):  
Hongzhou Yang ◽  
Yang Gao
Keyword(s):  
Real Time ◽  
Satellite Clock

scholarly journals A Decentralized Processing Schema for Efficient and Robust Real-time Multi-GNSS Satellite Clock Estimation

2019 ◽  
Vol 11 (21) ◽  
pp. 2595
Author(s):  
Jiang ◽  
Gu ◽  
Li ◽  
Ge ◽  
Schuh
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Precise Point Positioning ◽  
High Rate ◽  
Reference Network ◽  
Satellite Clock ◽  
Navigation Data ◽  
Data Analyst ◽  
New Strategy ◽  
Clock Estimation

Real-time multi-GNSS precise point positioning (PPP) requires the support of high-rate satellite clock corrections. Due to the large number of ambiguity parameters, it is difficult to update clocks at high frequency in real-time for a large reference network. With the increasing number of satellites of multi-GNSS constellations and the number of stations, real-time high-rate clock estimation becomes a big challenge. In this contribution, we propose a decentralized clock estimation (DECE) strategy, in which both undifferenced (UD) and epoch-differenced (ED) mode are implemented but run separately in different computers, and their output clocks are combined in another process to generate a unique product. While redundant UD and/or ED processing lines can be run in offsite computers to improve the robustness, processing lines for different networks can also be included to improve the clock quality. The new strategy is realized based on the Position and Navigation Data Analyst (PANDA) software package and is experimentally validated with about 110 real-time stations for clock estimation by comparison of the estimated clocks and the PPP performance applying estimated clocks. The results of the real-time PPP experiment using 12 global stations show that with the greatly improved computational efficiency, 3.14 cm in horizontal and 5.51 cm in vertical can be achieved using the estimated DECE clock.

Real-Time GPS Clock Monitoring with IGS Ultra-Rapid Products

2011 ◽  
Vol 301-303 ◽  
pp. 1293-1298
Author(s):  
Youn Jeong Heo ◽  
Jeongho Cho ◽  
Moon Beom Heo
Keyword(s):  
Real Time ◽  
Carrier Phase ◽  
Time Transfer ◽  
Satellite Clock ◽  
Short Term ◽  
Transfer Method ◽  
The Stability

The objective of this study is to develop a real-time strategy that results in higher precision than any real-time solutions currently available for GPS satellite clock monitoring. A real-time time transfer methodology was employed for satellite clock monitoring, composed of carrier phase smoothed code measurements and IGS ultra-rapid products to obtain precise satellite positions. The performance of the time transfer method was assessed by comparison with the results based on the all-in-view method using the broadcasting ephemeredes. The results showed that the stability of satellite clock monitoring for a short-term period was improved by the proposed method.

GNSS global real-time augmentation positioning: Real-time precise satellite clock estimation, prototype system construction and performance analysis

2018 ◽  
Vol 61 (1) ◽  
pp. 367-384 ◽  
Author(s):  
Liang Chen ◽  
Qile Zhao ◽  
Zhigang Hu ◽  
Xinyuan Jiang ◽  
Changjiang Geng ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Real Time ◽  
Prototype System ◽  
System Construction ◽  
Satellite Clock ◽  
And Performance ◽  
Clock Estimation

scholarly journals Random Optimization Algorithm on GNSS Monitoring Stations Selection for Ultra-Rapid Orbit Determination and Real-Time Satellite Clock Offset Estimation

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xu Yang ◽  
Qianxin Wang ◽  
Shuqiang Xue
Keyword(s):  
Real Time ◽  
Optimization Algorithm ◽  
Orbit Determination ◽  
Observation Data ◽  
Satellite Clock ◽  
Real Time Clock ◽  
Random Optimization ◽  
Earth Rotation Parameters ◽  
Clock Offset ◽  
Monitoring Stations

Geographical distribution of global navigation satellite system (GNSS) ground monitoring stations affects the accuracy of satellite orbit, earth rotation parameters (ERP), and real-time satellite clock offset determination. The geometric dilution of precision (GDOP) is an important metric used to measure the uniformity of the stations distribution. However, it is difficult to find the optimal configuration with the lowest GDOP when taking the 71% ocean limitation into account, because the ground stations are hardly uniformly distributed on the whole of the Earth surface. The station distribution geometry needs to be optimized and besides the stability and observational quality of the stations should also be taken into account. Based on these considerations, a method of configuring global station tracking networks based on grid control probabilities is proposed to generate optimal configurations that approximately have the minimum GDOP. A random optimization algorithm method is proposed to perform the station selection. It is shown that an optimal subset of the total stations can be obtained in limited iterations by assigning selecting probabilities for the global stations and performing a Monte Carlo sampling. By applying the proposed algorithm for observation data of 201 International GNSS Service (IGS) stations for 3 consecutive days, an experiment of ultra-rapid orbit determination and real-time clock offset estimation is conducted. The distribution effects of stations on the products accuracy are analyzed. It shows that (1) the accuracies of GNSS ultra-rapid observed and predicted orbits and real-time clock offset achieved using the proposed algorithm are higher than those achieved with the traditional method having the drawbacks of lacking evaluation indicators and being time-consuming, corresponding to the improvements 17.15%, 19.30%, and 31.55%, respectively. Only using 30 stations selected by the proposed method, the accuracies achieved reach 2.01 cm (RMS), 4.93 cm (RMS), and 0.20 ns (STD), respectively. Using 60 stations, the accuracies are 1.47 cm, 3.50 cm, and 0.17 ns, respectively. (2) With the increasing number of stations, the accuracies of the Global Positioning System (GPS) orbit and clock offset improve continuously, but more than 60 stations, the improvement on the orbit determination becomes more gradual, while for more than 30 stations, there is no appreciable increase in the accuracy of the real-time clock offset.

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