M. B. Heflin
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View article: JTRF2020-u2022: The First Update of JTRF202
JTRF2020-u2022: The First Update of JTRF202 Open
We report on JTRF2020-u2022, the first update of JTRF2020, the most recent terrestrial reference frame (TRF) solution computed at Jet Propulsion Laboratory (JPL). Determined with SREF -a square-root information filter and Dyer-McReynolds s…
A Global Combination of Geodetic Techniques at the Observation Level: New Perspectives on the Terrestrial Reference Frame Open
We describe the development and assessment of a new terrestrial reference frame (TRF) based on a combination of geodetic techniques at the observation level over the period 2010–2022. Included in the solution are observations from the Glob…
A New Realization of the Terrestrial Reference Frame: Combining GPS, SLR and VLBI at the Observation Level from 2010–2022 Open
We describe the development and assessment of a new terrestrial reference frame (TRF) based on combining GPS, SLR and VLBI at the observation level over the period 2010–2022. Included in the solution, in addition to station coordinat…
View article: Updating JTRF202
Updating JTRF202 Open
In recent years, new determinations of the ITRF based on full-blown reanalyses of frame inputs from the four space-geodetic techniques have been produced at intervals of 3-6 years. Between frame determinations, ITRF users must rely on pred…
View article: Updating Terrestrial Reference Frame using Sequential Computation Method
Updating Terrestrial Reference Frame using Sequential Computation Method Open
JTRF2020 is a recent contribution by NASA Jet Propulsion Laboratory to IERS as part of their effort to determine ITRF2020.  JTRF2020 is estimated daily using a sequential computational method (called "SREF") based on the SRIF and DMCS…
View article: An Insight on Scale Definition in JTRF202
An Insight on Scale Definition in JTRF202 Open
JTRF2020 is the latest TRF solution computed at JPL by assimilating frame input data submitted by the IVS, IGS, ILRS, and IDS for ITRF2020. Determined with SREF (Square-root Reference frame Estimation Filter), a computational code based on…
View article: Optimizing Earthquake Nowcasting With Machine Learning: The Role of Strain Hardening in the Earthquake Cycle
Optimizing Earthquake Nowcasting With Machine Learning: The Role of Strain Hardening in the Earthquake Cycle Open
Nowcasting is a term originating from economics, finance, and meteorology. It refers to the process of determining the uncertain state of the economy, markets or the weather at the current time by indirect means. In this paper, we describe…
View article: Clustering Analysis Methods for GNSS Observations: A Data‐Driven Approach to Identifying California's Major Faults
Clustering Analysis Methods for GNSS Observations: A Data‐Driven Approach to Identifying California's Major Faults Open
We present a data‐driven approach to clustering or grouping Global Navigation Satellite System (GNSS) stations according to observed velocities, displacements or other selected characteristics. Clustering GNSS stations provides useful scie…
View article: Clustering Analysis Methods for GNSS Observations: A Data-Driven Approach to Identifying California's Major Faults
Clustering Analysis Methods for GNSS Observations: A Data-Driven Approach to Identifying California's Major Faults Open
Earth and Space Science Open Archive This work has been accepted for publication in Earth and Space Science. Version of RecordESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary. Learn more abo…
View article: Improving access to geodetic imaging crustal deformation data using GeoGateway
Improving access to geodetic imaging crustal deformation data using GeoGateway Open
GeoGateway ( http://geo-gateway.org ) is a web-based interface for analysis and modeling of geodetic imaging data and to support response to related disasters. Geodetic imaging data product currently supported by GeoGateway include Global …
View article: Automated Estimation and Tools to Extract Positions, Velocities, Breaks, and Seasonal Terms From Daily GNSS Measurements: Illuminating Nonlinear Salton Trough Deformation
Automated Estimation and Tools to Extract Positions, Velocities, Breaks, and Seasonal Terms From Daily GNSS Measurements: Illuminating Nonlinear Salton Trough Deformation Open
This paper describes the methods used to estimate positions, velocities, breaks, and seasonal terms from daily Global Navigation Satellite System (GNSS) measurements. Break detection and outlier removal have been automated so that decades …
View article: Realization of time sequential estimation of terrestrial reference frame using square-root information filter and smoother
Realization of time sequential estimation of terrestrial reference frame using square-root information filter and smoother Open
<p>The JTRF2014 realization of terrestrial reference frame has adopted a weekly time series representation that can track dominant non-linear station motions including periodic and random variations. &#160;The realization is base…
An Advanced Formulation of Kalman Filter Time Series Reference Frame Realization for Geophysical Applications Open
<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 …
View article: Geocenter Motion from a Combination of GRACE Mascon and SLR Data
Geocenter Motion from a Combination of GRACE Mascon and SLR Data Open
<p>GRACE and GRACE Follow-On (FO) Level 2 data provide quasi-monthly, band-limited estimates of Stokes (geopotential, spherical harmonic) coefficients mostly reflecting surface mass variability due to non-tidal atmosphere, ocean, and…
View article: Temporal variations in ITRF station displacements analyzed with vector spherical harmonics
Temporal variations in ITRF station displacements analyzed with vector spherical harmonics Open
<p>The ITRF2014 candidate solutions DTRF2014 and JTRF2014 provide time-dependent station coordinates accounting for irregular station motions. DTRF2014 by DGFI-TUM expands the secular coordinate model via non-tidal loading correction…
View article: Fracture Advancing Step Tectonics Observed in the Yuha Desert and Ocotillo, CA, Following the 2010 M<sub>w</sub>7.2 El Mayor‐Cucapah Earthquake
Fracture Advancing Step Tectonics Observed in the Yuha Desert and Ocotillo, CA, Following the 2010 M<sub>w</sub>7.2 El Mayor‐Cucapah Earthquake Open
Uninhabited aerial vehicle synthetic aperture radar (UAVSAR) observations 2009–2017 of the Yuha Desert area and Global Positioning System (GPS) time series encompassing the region reveal a northward migrating pattern of deformation followi…
View article: COMPLEMENTARY AND ALTERNATIVE MEDICINE AMONG HIV-POSITIVE PATIENTS IN THE CURRENT TREATMENT ERA
COMPLEMENTARY AND ALTERNATIVE MEDICINE AMONG HIV-POSITIVE PATIENTS IN THE CURRENT TREATMENT ERA Open
provide whole team training.PDSA evaluation cycles can identify new opportunities in workflow patterns and training.