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Improved constraints on models of glacial isostatic adjustment: A review of the contribution of ground-based geodetic observations

King, M.A. (author), Altamimi, Z. (author), Boehm, J. (author), Bos, M. (author), Dach, R. (author), Elosegui, P. (author), Fund, F. (author), Hernández-Pajares, M. (author), Lavallee, D. (author), Riva, E.M. (author)

The provision of accurate models of Glacial Isostatic Adjustment (GIA) is presently a priority need in climate studies, largely due to the potential of the Gravity Recovery and Climate Experiment (GRACE) data to be used to determine accurate and continent-wide assessments of ice mass change and hydrology. However, modelled GIA is uncertain due...

journal article 2010

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Signal and noise in Gravity Recovery and Climate Experiment (GRACE) observed surface mass variations

Schrama, E.J.O. (author), Wouters, B. (author), Lavallée, D.A. (author)

The Gravity Recovery and Climate Experiment (GRACE) product used for this study consists of 43 monthly potential coefficient sets released by the GRACE science team which are used to generate surface mass thickness grids expressed as equivalent water heights (EQWHs). We optimized both the smoothing radius and the level of approximation by...

journal article 2007

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Aiming at a 1-cm orbit for low earth orbiters: Reduced-dynamic and kinematic precise orbit determination

Visser, P.N.A.M. (author), Van den IJssel, J. (author)

The computation of high-accuracy orbits is a prerequisite for the success of Low Earth Orbiter (LEO) missions such as CHAMP, GRACE and GOCE. The mission objectives of these satellites cannot be reached without computing orbits with an accuracy at the few cm level. Such a level of accuracy might be achieved with the techniques of reduced-dynamic...

journal article 2003

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Microblock rotations and fault coupling in SE Asia triple junction (Sulawesi, Indonesia) from GPS and earthquake slip vector data

Socquet, A. (author), Simons, W.J.F. (author), Vigny, C. (author), McCaffrey, R. (author), Subarya, C. (author), Sarsito, D. (author), Ambrosius, B. (author), Spakman, W. (author)

The island of Sulawesi, eastern Indonesia, is located within the triple junction of the Australian, Philippine, and Sunda plates and accommodates the convergence of continental fragments with the Sunda margin. We quantify the kinematics of Sulawesi by modeling GPS velocities and earthquake slip vectors as a combination of rigid block rotations...

journal article 2006

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Fast error analysis of continuous GPS observations

Bos, M.S. (author), Fernandes, R.M.S. (author), Williams, S.D.P. (author), Bastos, L. (author)

It has been generally accepted that the noise in continuous GPS observations can be well described by a power-law plus white noise model. Using maximum likelihood estimation (MLE) the numerical values of the noise model can be estimated. Current methods require calculating the data covariance matrix and inverting it, which is a significant...

journal article 2007

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Impact of Galileo on Global Ionosphere Map Estimation

The upcoming GNSS Galileo, with its new satellite geometry and frequency plan, will not only bring many benefits for navigation and positioning but also help to improve ionosphere delay estimation. This paper investigates ionosphere estimation with Galileo and compares it with the results from GPS-only and combined GPS-Galileo. The standard...

journal article 2006

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GPS-derived orbits for the GOCE satellite

Bock, H. (author), Jäggi, A. (author), Meyer, U. (author), Visser, P.N.A.M. (author), Van den IJssel, J.A.A. (author), Van Helleputte, T. (author), Heinze, M. (author), Hugentobler, U. (author)

The first ESA (European Space Agency) Earth explorer core mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) was launched on 17 March 2009 into a sun-synchronous dusk–dawn orbit with an exceptionally low initial altitude of about 280 km. The onboard 12-channel dual-frequency GPS (Global Positioning System) receiver delivers...

journal article 2011

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J2: An evaluation of new estimates from GPS, GRACE, and load models compared to SLR

Lavallée, D.A. (author), Moore, P. (author), Clarke, P.J. (author), Petrie, E.J. (author), Van Dam, T. (author), King, M.A. (author)

Changes in J2, resulting from past and present changes in Earth's climate, are traditionally observed by Satellite Laser ranging (SLR). Assuming an elastic Earth, it is possible to infer changes in J2 from changes in Earth's shape observed by GPS. We compare estimates of non-secular J2 changes from GPS, SLR, GRACE, and a load model. The GPS and...

journal article 2010

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Surface mass redistribution inversion from global GPS deformation and Gravity Recovery and Climate Experiment (GRACE) gravity data

Kusche, J. (author), Schrama, E.J.O. (author)

Monitoring hydrological redistributions through their integrated gravitational effect is the primary aim of the Gravity Recovery and Climate Experiment (GRACE) mission. Time?variable gravity data from GRACE can be uniquely inverted to hydrology, since mass transfers located at or near the Earth's surface are much larger on shorter timescales...

journal article 2005

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Short and zero baseline analysis of GPS L1 C/A, L5Q, GIOVE E1B, and E5aQ signals

De Bakker, P.F. (author), Tiberius, C.C.J.M. (author), Van der Marel, H. (author), Van Bree, R.J.P. (author)

Stochastic properties of GNSS range measurements can accurately be estimated using a geometry-free short and zero baseline analysis method. This method is now applied to dual-frequency measurements from a new field campaign. Results are presented for the new GPS L5Q and GIOVE E5aQ wideband signals, in addition to the GPS L1 C/A and GIOVE E1B...

journal article 2011

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GPS for structural health monitoring: A case study on the Basarab overpass cable-stayed bridge

Lepadatu, L. (author), Tiberius, C.C.J.M. (author)

The Basarab cable-stayed bridge is a newly built structure in Bucharest, Romania, which was inaugurated in June 2011. Before the oficial opening, in order to assure its qualification for trafic, it had to pass several loading tests with convoys of trucks and trams. For this, besides a priori evaluation using the Finite Element Method (FEM),...

journal article 2014

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Geometry-free undifferenced, single and double differenced analysis of single frequency GPS, EGNOS and GIOVE-A/B measurements

De Bakker, P.F. (author), Van der Marel, H. (author), Tiberius, C.C.J.M. (author)

This paper demonstrates a geometry-free GNSS measurement analysis approach and presents results of single frequency GPS, EGNOS and GIOVE short and zero baseline measurements. The purpose is to separate the different contributions to the measurement noise of pseudo range code and carrier phase observations at the receiver. The influence of...

journal article 2009

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Reassessing the 2006 Guerrero slow-slip event, Mexico: Implications for large earthquakes in the Guerrero Gap

Bekaert, D.P.S. (author), Hooper, A. (author), Wright, T.J. (author)

In Guerrero, Mexico, slow-slip events have been observed in a seismic gap, where no earthquakes have occurred since 1911. A rupture of the entire gap today could result in a Mw 8.2–8.4 earthquake. However, it remains unclear how slow-slip events change the stress field in the Guerrero seismic region and what their implications are for...

journal article 2015

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ADOP in closed form for a hierarchy of multi-frequency single-baseline GNSS models

Odijk, D. (author), Teunissen, P.J.G. (author)

Successful carrier phase ambiguity resolution is the key to high-precision positioning with Global Navigation Satellite Systems (GNSS). The ambiguity dilution of precision (ADOP) is a well-known scalar measure which can be used to infer the strength of the GNSS model for carrier phase ambiguity resolution. In this contribution we present...

journal article 2008

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Monitoring travel times in an urban network using video, GPS and Bluetooth

Jie, L. (author), Van Zuylen, H.J. (author), Chunhua, L. (author), Shoufeng, L. (author)

The travel time is an important measure for the quality of traffic. This paper discusses a few methods to measure or estimate the travel time in urban road networks. First of all, it is important to know that urban travel times display a large variation, so that the measurement of a single (average) travel time is not so meaningful. The travel...

journal article 2011

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Accuracy assessment of the monthly GRACE geoids based upon a simulation

Schrama, E.J.O. (author), Visser, P.N.A.M. (author)

journal article 2007

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Monitoring Megathrust-Earthquake-Cycle-Induced Relative Sea-Level Changes near Phuket, South Thailand, Using (Space) Geodetic Techniques

Naeije, M.C. (author), Simons, W.J.F. (author), Pradit, Siriporn (author), Niemnil, Sommart (author), Thongtham, Nalinee (author), Bin Mustafar, M.A. (author), Noppradit, Prakrit (author)

Temporal changes in vertical land motion (VLM) in and around Phuket Island in southern Thailand following the great 2004 Sumatra–Andaman megathrust earthquake have impacted the relative sea-level change estimates based on tide-gauge (TG) records. To better monitor the VLM, two new continuous global navigation satellite system (GNSS) stations...

journal article 2022

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Impact of Climate Change Parameters on Groundwater Level: Implications for Two Subsidence Regions in Iran Using Geodetic Observations and Artificial Neural Networks (ANN)

Haji-Aghajany, Saeid (author), Amerian, Yazdan (author), Amiri Simkooei, A. (author)

This study aims to investigate how changes in meteorological indicators affect groundwater resources, and hence to predict groundwater levels using these indicators, particularly in regions experiencing drought and subsidence. Precipitation, temperature, evapotranspiration and precipitable water vapor (PWV) are important meteorological...

journal article 2023

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A Tsunami Generated by a Strike-Slip Event: Constraints From GPS and SAR Data on the 2018 Palu Earthquake

Simons, W.J.F. (author), Broerse, D.B.T. (author), Kleptsova, O.S. (author), Nijholt, N. (author), Pietrzak, J.D. (author), Naeije, M.C. (author), Lhermitte, S.L.M. (author), Visser, P.N.A.M. (author), Riva, R.E.M. (author)

A devastating tsunami struck Palu Bay in the wake of the 28 September 2018 M_w = 7.5 Palu earthquake (Sulawesi, Indonesia). With a predominantly strike-slip mechanism, the question remains whether this unexpected tsunami was generated by the earthquake itself, or rather by earthquake-induced landslides. In this study we examine the...

journal article 2022

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A Transient in Surface Motions Dominated by Deep Afterslip Subsequent to a Shallow Supershear Earthquake: The 2018 M_w7.5 Palu Case

Nijholt, N. (author), Simons, W.J.F. (author), Efendi, J. (author), Sarsito, D. A. (author), Riva, R.E.M. (author)

The 2018 (Formula presented.) Palu earthquake is a remarkable strike-slip event due to its nature as a shallow supershear fault rupture across several segments and a destructive tsunami that followed coseismic deformation. GPS offsets in the wake of the 2018 earthquake display a transient in the surface motions of northwest Sulawesi. A...

journal article 2021