scholarly journals A Robust and Multi-Weighted Approach to Estimating Topographically Correlated Tropospheric Delays in Radar Interferograms

Sensors ◽  
2016 ◽  
Vol 16 (7) ◽  
pp. 1078 ◽  
Author(s):  
Bangyan Zhu ◽  
Jiancheng Li ◽  
Zhengwei Chu ◽  
Wei Tang ◽  
Bin Wang ◽  
...  
Keyword(s):  
Tropospheric Delays

scholarly journals GPS Coordinate Estimates by “a priori” Tropospheric Delays from NWP using Ultra-Rapid Orbits

2009 ◽  
Vol 49 (4-5) ◽  
Author(s):  
M. Boccolari ◽  
S. Fazlagic' ◽  
R. Santangelo
Keyword(s):  
A Priori ◽  
Tropospheric Delays

Modeling of Tropospheric Delays Using ANFIS

2016 ◽  
Author(s):  
Wayan Suparta ◽  
Kemal Maulana Alhasa
Keyword(s):  
Tropospheric Delays

scholarly journals Tropospheric Delay Correction Based on a Three-Dimensional Joint Model for InSAR

2019 ◽  
Vol 11 (21) ◽  
pp. 2542
Author(s):  
Huaping Xu ◽  
Yao Luo ◽  
Bo Yang ◽  
Zhaohong Li ◽  
Wei Liu
Keyword(s):  
Urban Areas ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Joint Model ◽  
Three Dimensions ◽  
Superior Performance ◽  
Tropospheric Delay ◽  
Natural Scenes ◽  
Delay Correction ◽  
Tropospheric Delays

Tropospheric delays in spaceborne Interferometric Synthetic Aperture Radar (InSAR) can contaminate the measurement of small amplitude earth surface deformation. In this paper, a novel TXY-correlated method is proposed, where the main tropospheric delay components are jointly modeled in three dimensions, and then the long-scale and topography-correlated tropospheric delay components are corrected simultaneously. Moreover, the strategies of scale filtering and alternative iteration are employed to accurately retrieve all components of the joint model. Both the TXY-correlated method and the conventional phase-based methods are tested with a total of 25 TerraSAR-X/TanDEM-X images collected over the Chaobai River site and the Renhe Town of Beijing Shunyi District, where natural scenes and man-made targets are contained. A higher correction rate of tropospheric delays and a greater reduction in spatio-temporal standard deviations of time series displacement are observed after delay correction by the TXY-correlated method in both non-urban and urban areas, which demonstrate the superior performance of the proposed method.

scholarly journals Validation of a New Model for the Estimation of Residual Tropospheric Delay Error Under Extreme Weather Conditions

2018 ◽  
Author(s):  
Ildikó Juni ◽  
Szabolcs Rózsa
Keyword(s):  
Systematic Error ◽  
Solution Space ◽  
Global Navigation Satellite Systems ◽  
Performance Standard ◽  
Tropospheric Delay ◽  
Electron Content ◽  
Numerical Weather ◽  
Numerical Weather Models ◽  
Tropospheric Delays ◽  
Weather Models

The electromagnetic signals of the Global Navigation Satellite Systems (GNSS) satellites suffer delays while propagating through the troposphere. The tropospheric delay is a significant systematic error of GNSS positioning. For safety-of-life applications of positioning many systematic error effects are either mitigated or eliminated in the positioning solution. Space based augmentation systems provide corrections for the orbital and satellite clock error, the ionospheric effects, etc. Moreover advanced GNSS provide dual frequency code observations for civilian users to eliminate the ionospheric delays caused by the electron content of the upper atmosphere. Nevertheless tropospheric delays are still taken into account using empirical models.For safety-of-life applications besides the accuracy of the positioning, the integrity of the positioning service is an important factor, too. The integrity information includes the maximal positioning error at an extremely rare probability level, called protection level to ensure highly reliable position solution in the aviation. The Radio Technical Commission for Aeronautics Minimum Operational Performance Standard (RTCA MOPS) recommends 0.12 m as the maximum zenith tropospheric error in terms of standard deviation. Previous studies show that this recommendation seems to be too conservative leading to a lower service availability. Therefore a more realistic integrity model has to be derived for the estimation of maximal residual tropospheric delay error.In the recent years many advanced empirical tropospheric delay models have been formulated compared to the one recommended by the RTCA. Recently new integrity models have been derived for estimating the maximum residual tropospheric delay error using numerical weather models under real extreme weather.The aim of this paper is to study the reliability of these models conditions. In order to achieve this, high-resolution numerical weather models were ray-traced using an improved ray-tracing algorithm to evaluate the slant and zenith tropospheric delays with the geographical resolution of 0.1° × 0.1°.

Estimation and Mitigation of the Main Errors for Centimetre-level Compass RTK Solutions over Medium-Long Baselines

2011 ◽  
Vol 64 (S1) ◽  
pp. S113-S126 ◽  
Author(s):  
Hairong Guo ◽  
Haibo He ◽  
Jinlong Li ◽  
Aibing Wang
Keyword(s):  
A Priori ◽  
Satellite Orbit ◽  
Tropospheric Delay ◽  
List Type ◽  
Triple Frequency ◽  
Precise Ephemeris ◽  
Height Component ◽  
Orbit Errors ◽  
Tropospheric Delays ◽  
Long Baselines

Centimetre-level RTK solutions are mainly influenced by satellite orbit errors, ionospheric and tropospheric delays, and measurement noise (including multipath effects). Estimation and mitigation of the main errors for the CM-level Compass RTK solutions over medium-long baselines are investigated. Tests conducted for this research lead to the following conclusions: 1.For 100 km baselines, a 4 cm error in height component will be induced by a 10 m orbit error. For longer baselines, rapid precise ephemeris will be needed for CM-level accuracy RTK solutions.2.The residual ionospheric delay error can be eliminated using the optimal triple-frequency ionosphere-free linear combination with the coefficients of 2·6087, −0·5175 and −1·0912 respectively for observations on f1, f2 and f3 frequencies. This combination is optimal in terms of its noise level, e.g., the noise is only amplified three times. It can be used for high accuracy RTK positioning.3.The residual tropospheric delay can be resolved for the introduced relative zenith tropospheric delay (RZTD) parameters.It is shown that the RTK solutions estimated from the least squares (LS) with the RZTD parameters are worse than that without these parameters. For instance, the errors in the height components are amplified approximately three times, which may be caused by the strong correlation between the introduced RZTD parameters and the height components. However, considering the fact that the residual zenith tropospheric delays vary slowly with time and the variation can be assumed to follow a random walk process, the RTK solutions can be improved using the Kalman filter and a priori information for the RZTD parameters.

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