scholarly journals KALREF-A Kalman filter and time series approach to the International Terrestrial Reference Frame realization

2015 ◽  
Vol 120 (5) ◽  
pp. 3775-3802 ◽  
Author(s):  
Xiaoping Wu ◽  
Claudio Abbondanza ◽  
Zuheir Altamimi ◽  
T. Mike Chin ◽  
Xavier Collilieux ◽  
...  
Keyword(s):  
Time Series ◽  
Kalman Filter ◽  
Reference Frame ◽  
Terrestrial Reference Frame ◽  
International Terrestrial Reference Frame ◽  
Time Series Approach

An Advanced Formulation of Kalman Filter Time Series Reference Frame Realization for Geophysical Applications

2020 ◽  
Author(s):  
Xiaoping Wu ◽  
Bruce Haines ◽  
Michael Heflin ◽  
Felix Landerer
Keyword(s):  
Time Series ◽  
Kalman Filter ◽  
Reference Frame ◽  
State Vector ◽  
Terrestrial Reference Frame ◽  
Covariance Matrices ◽  
Time Variable ◽  
The State ◽  
Geocenter Motion ◽  
Over Time

<p>A Kalman filter and time series approach to the International Terrestrial Reference Frame (ITRF) realization (KALREF) has been developed and used in JPL. KALREF combines weekly or daily SLR, VLBI, GNSS and DORIS data and realizes a terrestrial reference frame in the form of time-variable geocentric station coordinate time series. The origin is defined at nearly instantaneous Center-of-Mass of the Earth system (CM) sensed by weekly SLR data and the scale is implicitly defined by the weighted averages of those of weekly SLR and daily VLBI data. The standard KALREF formulation describes the state vector in terms of time variable station coordinates and other constant parameters. Such a formulation is fine for station positions and their uncertainties or covariance matrices at individual epochs. However, coordinate errors are strongly correlated over time given KALREF’s unique nature of combining different technique data with various frame strengths through local tie measurements and co-motion constraints and its use of random walk processes. For long time series and large space geodetic networks in the ITRF, KALREF cannot keep track of such correlations over time. If they are ignored when forming geocentric displacements for geophysical inverse or network shift geocenter motion studies, the covariance matrices of coordinate differences cannot adequately represent those of displacements. Consequently, significant non-uniqueness and inaccuracies would occur in the results of studies using such matrices. To overcome this difficulty, an advanced KALREF formulation is implemented that features explicit displacement parameters in the state vector that would allow the Kalman filter and smoother to compute and return covariance matrices of displacements. The use of displacement covariance matrices reduces the impact of time correlated errors and completely solves the non-uniqueness problem. However, errors in the displacements are still correlated in time. Further calibrations are needed to accurately assess covariance matrices of derivative quantities such as averages, velocities and accelerations during various time periods. We will present KALREF results of the new formulation and their use along with newly reprocessed RL06 GRACE gravity data in a new unified inversion for geocenter motion.</p>

scholarly journals ITRF2014: A new release of the International Terrestrial Reference Frame modeling nonlinear station motions

2016 ◽  
Vol 121 (8) ◽  
pp. 6109-6131 ◽  
Author(s):  
Zuheir Altamimi ◽  
Paul Rebischung ◽  
Laurent Métivier ◽  
Xavier Collilieux
Keyword(s):  
Reference Frame ◽  
Terrestrial Reference Frame ◽  
International Terrestrial Reference Frame

scholarly journals Accuracy of the International Terrestrial Reference Frame origin and Earth expansion

2011 ◽  
Vol 38 (13) ◽  
pp. n/a-n/a ◽  
Author(s):  
X. Wu ◽  
X. Collilieux ◽  
Z. Altamimi ◽  
B. L. A. Vermeersen ◽  
R. S. Gross ◽  
...  
Keyword(s):  
Reference Frame ◽  
Terrestrial Reference Frame ◽  
International Terrestrial Reference Frame

Impact of loading effects on determination of the International Terrestrial Reference Frame

2010 ◽  
Vol 45 (1) ◽  
pp. 144-154 ◽  
Author(s):  
Xavier Collilieux ◽  
Zuheir Altamimi ◽  
David Coulot ◽  
Tonie van Dam ◽  
Jim Ray
Keyword(s):  
Reference Frame ◽  
Terrestrial Reference Frame ◽  
International Terrestrial Reference Frame ◽  
Loading Effects

IDENTIFIKASI MEKANISME SESAR DI BAGIAN TIMUR PULAU JAWA DENGAN MENGGUNAKAN DATA GNSS KONTINYU 2010-2016

2019 ◽  
Vol 3 ◽  
pp. 805
Author(s):  
Henri Kuncoro ◽  
Gusti Ayu Jessy Kartini ◽  
Irwan Meilano ◽  
Susilo Susilo
Keyword(s):  
Strain Rate ◽  
Reference Frame ◽  
Terrestrial Reference Frame ◽  
International Terrestrial Reference Frame

Pulau Jawa terletak tepat di utara zona subduksi jawa yang merupakan zona pertemuan Lempeng Indo-Australia dengan Lempeng Sunda. Beberapa Sesar terbentuk di Pulau Jawa mengakomodasi stress yang dihasilkan oleh subduksi jawa yang berada di selatan Pulau Jawa. Studi deformasi dengan menggunakan data GNSS telah dilakukan untuk mengestimasi laju geser dari sesar-sesar utama di Pulau Jawa. Koulali dkk (2016) mengestimasi laju geser untuk Sesar Baribis dan Sesar Kendeng sebesar 2.3 – 5.6 mm/tahun dan dinyatakan sebagai sesar-sesar aktif. Pada studi ini, 15 data GNSS kontinyu dari tahun 2010 hingga 2016 di bagian timur Pulau Jawa digunakan untuk mengidentifikasi mekanisme sesar yang berada di wilayah ini meliputi Sesar Kendeng dan ekstensinya. Data fase GPS dari setiap stasiun GNSS diolah dengan menggunakan GAMIT/GLOBK 10.6 untuk mendapatkan koordinat di dalam sistem koordinat kartesian 3D di dalam kerangka referensi International Terrestrial Reference Frame 2008 (ITRF2008). Sebanyak 15 vektor kecepatan GNSS digunakan untuk menghitung strain rate dan laju geser untuk setiap segmen sesar yang dilalui oleh 3 profil. Ketiga profil tersebut menunjukkan adanya kompresi sebagai akomodasi stress dari subduksi Jawa dan laju geser untuk segmen barat Sesar Kendeng, segmen timur Sesar Kendeng, dan ekstensinya sebesar 1.93 mm/tahun, 0.90 mm/tahun, dan 0.60 mm/tahun secara berurutan dengan mekanisme sesar mengiri. Mekanisme yang sama yang terjadi pada ekstensi Sesar Kendeng menunjukkan adanya potensi sumber gempa yang baru di sekitar Selat Madura. Hal ini merupakan informasi penting untuk mengidentifikasi potensi sumber gempa dari Sesar Kendeng dan ekstensinya mengingat zona dari sesar aktif ini merupakan zona yang berpenduduk cukup padat.

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