FG Satellitengeodäsie

12 Items

Recent Submissions
Remote sensing ionospheric variations due to total solar eclipse, using GNSS observations

Alizadeh, Mohamad Mahdi ; Schuh, Harald ; Zare, Saeed ; Sobhkhiz-Miandehi, Sahar ; Tsai, Lung-Chih (2019-10-01)

For years great interest has been taken in the effects of physical phenomena on ionosphere structure. A total solar eclipse was visible in North America on August 21st, 2017. This event offered a great opportunity for remote sensing the ionospheric behavior under the eclipse condition. In this study we investigated the effects of total solar eclipse on variations of Total Electron Content (TEC)...

Automatic Calibration of Process Noise Matrix and Measurement Noise Covariance for Multi-GNSS Precise Point Positioning

Zhang, Xinggang ; Li, Pan ; Tu, Rui ; Lu, Xiaochun ; Ge, Maorong ; Schuh, Harald (2020-04-02)

The Expectation-Maximization algorithm is adapted to the extended Kalman filter to multiple GNSS Precise Point Positioning (PPP), named EM-PPP. EM-PPP considers better the compatibility of multiple GNSS data processing and characteristics of receiver motion, targeting to calibrate the process noise matrix Qt and observation matrix Rt, having influence on PPP convergence time and precision, with...

Drift of the Earth’s Principal Axes of Inertia from GRACE and Satellite Laser Ranging Data

Ferrándiz, José M. ; Modiri, Sadegh ; Belda, Santiago ; Barkin, Mikhail ; Bloßfeld, Mathis ; Heinkelmann, Robert ; Schuh, Harald (2020-01-18)

The location of the Earth’s principal axes of inertia is a foundation for all the theories and solutions of its rotation, and thus has a broad effect on many fields, including astronomy, geodesy, and satellite-based positioning and navigation systems. That location is determined by the second-degree Stokes coefficients of the geopotential. Accurate solutions for those coefficients were limited ...

On the eve of the 100th anniversary of IAU Commission 19/A2 “Rotation of the Earth”

Malkin, Zinovy ; Gross, Richard ; McCarthy, Dennis ; Brzeziński, Aleksander ; Capitaine, Nicole ; Dehant, Véronique ; Huang, Chengli ; Schuh, Harald ; Vondrák, Jan ; Yatskiv, Yaroslav (2018-12)

IAU Commission 19 began in 1919 with the birth of the IAU at the Brussels Conference, where Standing Committee 19 on Latitude Variations was established as one of 32 standing committees. At the first IAU General Assembly in 1922, Standing Committee 19 became Commission 19 “Variation of Latitude”. In the beginning, the main topic of the Commission was the investigation of polar motion. Later, it...

Retrieving Precipitable Water Vapor From Shipborne Multi‐GNSS Observations

Wang, Jungang ; Wu, Zhilu ; Semmling, Maximilian ; Zus, Florian ; Gerland, Sebastian ; Ramatschi, Markus ; Ge, Maorong ; Wickert, Jens ; Schuh, Harald (2019-05-15)

Precipitable water vapor (PWV) is an important parameter for climate research and a crucial factor to achieve high accuracy in satellite geodesy and satellite altimetry. Currently Global Navigation Satellite System (GNSS) PWV retrieval using static Precise Point Positioning is limited to ground stations. We demonstrated the PWV retrieval using kinematic Precise Point Positioning method with shi...

Estimating integrated water vapor trends from VLBI, GPS,and numerical weather models: sensitivity totropospheric parameterization

Balidakis, Kyriakos ; Nilsson, Tobias ; Zus, Florian ; Glaser, Susanne ; Heinkelmann, Robert ; Deng, Zhiguo ; Schuh, Harald (2018-06-20)

In this study, we estimate integrated water vapor (IWV) trends from very long baseline interferometry (VLBI) and global navigation satellite systems (GNSS) data analysis, as well as from numerical weather models (NWMs). We study the impact of modeling and parameterization of the tropospheric delay from VLBI on IWV trends. We address the impact of the meteorological data source utilized to model...

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

Jiang, Xinyuan ; Gu, Shengfeng ; Li, Pan ; Ge, Maorong ; Schuh, Harald (2019-11-05)

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 be...

Mitigation of Unmodeled Error to Improve the Accuracy of Multi-GNSS PPP for Crustal Deformation Monitoring

Zheng, Kai ; Zhang, Xiaohong ; Li, Xingxing ; Li, Pan ; Chang, Xiao ; Sang, Jizhang ; Ge, Maorong ; Schuh, Harald (2019-09-25)

High-rate multi-constellation global navigation satellite system (GNSS) precise point positioning (PPP) has been recognized as an efficient and reliable technique for large earthquake monitoring. However, the displacements derived from PPP are often overwhelmed by the centimeter-level noise, therefore they are usually unable to detect slight deformations which could provide new findings for geo...

Assessment of Different Stochastic Models for Inter-System Bias between GPS and BDS

Jiang, Nan ; Xu, Tianhe ; Xu, Yan ; Xu, Guochang ; Schuh, Harald (2019-04-25)

Inter-system bias (ISB) will affect accuracy and processing time in integrated precise point positioning (PPP), and ISB stochastic models will largely determine the quality of ISB estimation. Thus, the impacts of four different stochastic models of ISB processing will be assessed and studied in detail to further reveal the influence of ISB in positioning. They are ISB-PW considering ISB as a pi...

GNSS inter-system bias estimation, modeling, and prediction

Jiang, Nan (2019)

Up to now, the precise point positioning (PPP) has stepped from the single system mode into the multi-GNSS combination. The key point of multi-GNSS integrated PPP is to carefully calibrate the inter-system-bias (ISB) between different systems. If ISB can be modeled, this error will be well corrected. It will significantly increase the usability of satellites and enhance compatibility and intero...

Frame tie based on VLBI observations to near-field spacecraft

Liu, Li (2019)

The objective of this work is to find approaches to realize the link of celestial reference frames, the dynamic spacecraft reference frame and the more stable and accurate International Celestial Reference Frame (ICRF), by observing the spacecraft with Very Long Baseline Interferometry (VLBI). In this work, the phase referencing observations to Global Navigation Satellite System (GNSS) satellit...

High-frequency earth rotation variations deduced from altimetry-based ocean tides

Madzak, Matthis ; Schindelegger, Michael ; Böhm, Johannes ; Bosch, Wolfgang ; Hagedoorn, Jan (2016)

A model of diurnal and semi-diurnal variations in Earth rotation parameters (ERP) is constructed based on altimetry-measured tidal heights from a multi-mission empirical ocean tide solution. Barotropic currents contributing to relative angular momentum changes are estimated for nine major tides in a global inversion algorithm that solves the two-dimensional momentum equations on a regular 0.5^\...