Director’s Report:

CRTN, Epoch Update & Dynamic Datum

Yehuda Bock

California Spatial Reference Center (CSRC)

Scripps Orbit and Permanent Array Center (SOPAC)

Institute of Geophysics and Planetary Physics (IGPP)

Scripps Institution of Oceanography (SIO)

University of California San Diego (UCSD)

May 4, 2017

IGPP, La Jolla

Summary

• CRTN update

• Status 2017.00 epoch date for California

• Dynamic datum

• Earthquake and Local Tsunami Early Warning System

Director: Yehuda Bock

Coordinator: Maria Turingan

Analysis: Peng Fang

System Administrator: Anne Sullivan

Programmers: Allen Nance, TBD

Archivist & Web Admin: TBD

CRTN Engineer: Matt Norenberg

Graduate Students: Dara Goldberg, Lauren Coden, Minghua Wang

Consultant: John Canas, PLS

SOPAC/CSRC Group

Chairperson: Richard C. Maher

Vice-Chairperson: Scott P. Martin

Secretary: Thomas Dougherty

Treasurer: Jim McNeil

Member: Bryan Banister

Member: Kimberley Holtz

Member: Greg Helmer

Member: Ken Joyce

Non-elected:

Past Chairperson: Art Andrew

UCSD representative: John Orcutt

Director of IGPP: Steve Constable

NGS Adviser: Dana Caccamise

CSRC Director: Yehuda Bock

CSRC Executive Committee

CRTN Station Status @ May 2, 2017 11:45 PM

Started in 2003, 1 Hz RTCM

3.0 data are available from

420 stations from 2 CRTN

servers (SC: 207 stations;

NC: 213 stations) at SIO with

a latency of ~0.4-1.0 s. Data

directly collected from

SCIGN/PBO stations via

UCSD’s HPWREN, and from

servers at UNAVCO/PBO,

USGS Pasadena, UC

Berkeley, Caltrans, Orange

County, and Metropolitan

Water District.

NAD83(NSRS2007) 2011.0

coordinates transmitted, with

station metadata in RTCM

3.0 format

CRTN Update

• Nearly 800 users• Increased number of stations to 420• Incorporated 28 USGS/Pasadena stations• Completed repairs and maintenance at 24

SCIGN/SOPAC stations, includes OCRTN (Topcon GNSS receivers)

• Determined location for new Gillespie Field station and rebuilding NSSS in SW corner of County (San Diego County – Ray Mathe)

• Worked with USGS to diagnose Topcon firmware issues

CRTN Consortium Members

1. City of Los Angeles, Department of Public Works, Bureau of Engineering, Cesar Bregaudit, Robert Nielsen

2. Riverside County Flood Control and Water Conservation District, Jim McNeil

3. Orange County Public Works, Art Andrew4. San Diego County, Department of Public Works, Ray Mathe5. Riverside County Transportation Department, Rick Lantis, Ed

Hunt, Tim Rayburn, David McMillan6. Santa Clara Valley Water District, Kris Puthoff 7. City of Long Beach, Gas and Oil, Kimberley Holtz8. California Spatial Reference Center, Rich Maher9. Scripps Institution of Oceanography, UCSD, Yehuda Bock10. California Department of Transportation, Scott Martin, Mark

Turner11. Swift Navigation, James Murphy, Grant Hausler, Rob Hranac

CRTN Contributing Members1. Adkan Engineers, Tom Chrisman2. Bock and Clark Corporation, Eric Berben3. Burkett and Wong Engineers, Casey Lynch4. California American Water, Stephen San Nicolas5. Cardno Inc., Sean Fitzpatrick6. Coast Surveying, Inc., Ken Kasbohm, Gwen del Castillo7. Dixon Marine Services, Inc., Jeff Haran8. East Bay Municipal Water District, Steve Martin and Tara Sweet9. East Bay Regional Parks, Duncan Marshall10. Helix Water District, Rebecca Vanegas11. Honda Research Institute USA, Inc., Paul Cummings12. Japan Aerospace Exploration Agency, Satoshi Kogure, Mike Ramirez13. Terra-Mark Surveying, Robert Shellman14. LocusView Solutions, Eric Gakstatter15. MBS Land Surveys, Michael B. Stanton16. PSOMAS, Jeremy Evans17. Quantum Spatial, Kenny Roberts18. Rail Surveyors and Engineers Incorporated, Cody Festa19. RBF Consulting, Company of Michael Baker Corporation20. RSE Inc., Cody Festa21. Salsbury Engineering, Inc., Jon Gauthier22. San Francisco Water Department, Edward Peterson23. Southern California Gas Company, Gregory Irwin24. SubCarrier Systems Corp., David Kelley25. US Army Corps of Engineers, Ronald Spencer

Sample of CRTN Users

• An NTRIP account (username & password) is required, requested by on-line registration: (https://www.surveymonkey.com/s/CRTN_Registration)

• 792 companies/agencies registered (up from 699 at 2016 Fall Meeting)

• > 25 multi-account users

• Recent accounts

• 751. U.S. Army Corps of Engineers (shoreline project)

• 756. Yamaha Motor Corporation (helicopter crop dusting)

• 759. Apollo Robotic Systems (precise UAV location)

• 763. Vernadero Group Inc. (rare plants survey at MCAS Miramar)

• 770. Brent Harvey Consulting, Inc. (golf course irrigation systems)

• 773. Pioneer Hi-Bred, Inc. (testing corn varieties, agricultural plots)

• 776. CB&I Federal Services (radiological & chemical remediation on former U.S. Navy properties)

• 785. City of Ventura, Water (map water meters, valves, fire hydrants)

• 788. Kaweah Delta Water Conservation District (subsidence mapping)

• 787. Jingchi Corp. (automobile industry, autonomous driving)

Connections to CRTN Stations through March 2017

CRTN Usage: Top Connections in March 2017

Total Usage: 48,238 Connections

34,395: Swift Navigation (latest CRTN Consortium Member)

1290: Javad, Bay Area

607: PrecisePositioning, San Francisco, UAV mapping for

telecom industry

589: Locusview, GIS, natural gas and water

447: Jose Casanova, Southern California surveying

427: Cozad & Fox, Hemet, civil engineering, surveying

401: Yamaha Motor, Orange & Napa, crop dusting helicopter

378: Driscoll’s, central California, agriculture

373: Tulare County, surveying

370: Honda, Mountainview, high precision ground-truth

navigation data

• Work authorized by Mark Turner on March 16, 2016• Updated metadata for Caltrans real-time stations in

SOPAC database (CVSRN, CCSRN), Bryan Banister and Eric Adney

• Included remaining CVSRN and CCSRN data into CRTN (collect RINEX data from all Caltrans stations and store in SOPAC archive) – Added full set to “Master List” for processing

• Backfilled missing RINEX data from CVSRN• Add new California stations in California (USGS, PBO,

other) into the Master List for reprocessing• Double check metadata and completeness of data for

all stations on Master list• Assign preliminary quality codes to stations• Convert to ITRF2014/IGS14 through global repro• Reprocess of entire California data set while continuing

forward with regular SOPAC processing, in ITRF2014 reference frame

Caltrans Task Order: New Epoch Date for California

CSRC 2017.00 Epoch Date

• Finalized list of stations (885 active stations; 84 inactive stations)

• Converted to new ITRF2014/IGS14 global reference frame by reanalyzing ~400 global stations, from 1995 to transition to ITRF2014 in early 2017

• Only GPS data input to the analysis• Products:

o List of coordinates at epoch 2017.00 (ITRF2014/IGS14, WGS84 geodetic, sigmas; NSRS geodetic and sigmas)

o Final report, working with CRSC committeeo Web posting, in progress

New CSRS Coordinate Epoch

2007.00 – 511 stations2009.00 – 766 2011.00 – 830 2017.00 – 971

CRTN - 420 stations

ITRF2008 to ITRF2014

Connect CSRS to NSRS:NAD83 (NSRS2007)?NSRS (2022)?

Continuous GPS stations for 2017.00 epoch date:

ITRF2008 velocities

50 mm/yr

Significant Earthquakes in California 1992-2017

Detrended Displacement Time Series (1996-2017)

Coseismic & Postseismic Motions

CRRS

DHLG

GLRS

East

Up

North

0.24 ft0.16 ft

Surveyors do not like changing reference frames and coordinates…

In California and other seismically active regions this is not possible. Therefore, CSRC publishes a new epoch date every few years (2007.00, 2009.00, 2011.00, 2017.00, …).

Dynamic Datums

Dynamic Datums - II

Reference frames need to be periodically updated to accommodate new types and number of observations and new stations.

There are other phenomena other than tectonic motions that cause significant changes in coordinates (e.g., vertical land motion) requiring quality control to identify and possibly discard stations.

Example of Non-Tectonic Motions

(Station BOMG near Salton Sea)

0.26 ft

0.26 ft

0.11 ft

BOMG

Waste

treatment

plant

Non-Tectonic Motions

0.26 ft

0.26 ft

0.11 ft

Dynamic Datums - III

Creating a new epoch date for coordinates with an increase in number of stations modifies the reference system, realized through the epoch-date coordinates of the permanent GNSS stations. So does the change from, say, ITRF2008 to ITRF2014

You can think of the reference frame as a triangulated network in 2-D (or a polyhedron in 3-D) whose shape and size changes in time. The epoch-date coordinates are a snapshot at a particular epoch of time with respect to a global reference frame (ITRF2014/IGS14)

Dynamic Datums - IV

The reference frame is defined by the positions of the permanent GNSS at a particular epoch of time (now CSRC Epoch 2011.00), and you can update CSRS station coordinates to any other epoch through, for example, SOPAC’s SECTOR application.

However, estimating the true-of-date coordinates of a new surveyed station with respect to the reference frame requires an additional step.

There are at least two approaches: interpolation or crustal deformation model

SECTOR Utility

Epoch-Date Coordinates

http://sopac.ucsd.edu/processing/coordinates/

Interpolation – Model Independent

Crustal Deformation Model

Earthquake Cycle – Elastic Rebound Theory

Crustal Deformation Model: Fault transects

Tong et al., 2014

Crustal Deformation Model

Coseismic Motion: 2010 Mw7.2 El Mayor-Cucapah

Gonzalez et al., 2014

Dynamic Datums - V

• A GNSS survey (say RTK) is conducted at some date and positioned wrt the CSRS (say, in real time using CRTN). The surveyor receives the metadata for the reference station(s) and true-of-date ITRF coordinates as part of the RTCM3 message, consistent with the IGS frame and orbits, and estimates coordinates of surveyed marks with his/her usual field device. The true-of-date coordinates of the CRTN stations are derived using a SECTOR-type app.

• The surveyor can refer back to an earlier epoch date using an up-to-date HTDP-type model, which is consistent with the CSRS, since the model was derived from the CSRN coordinate time series.

• Whether at the survey date or an earlier date, the ITRF positions can then be converted to geodetic coordinates (say with respect to the NSRS) and then to map coordinates, if required.

• Is implementation and acceptance of a dynamic datum made any easier now that maps are digital, or after paper maps have been digitized?

Advantages of Seismogeodesy• Very broadband instrument that

doesn’t clip even in the near field of the largest earthquake

• Reduces baseline errors in doubly-integrated accelerometer data and preserves static offset

• Is not affected by regional magnitude saturation for earthquakes greater than ~M7.5

• Able to detect P-wave arrivals, not possible with GNSS data alone

• Provides very high-rate displacement and velocity waveforms

• Provides two degrees of freedom (three independent observations of ground motion)

• Is less susceptible to false alarms for EEW

Seismogeodesy: Real-time optimal integration of GNSS

and seismic data in the near field of strong motion

1-10 Hz100-200 Hz

DisplacementsDoubly Integrate

Accelerations

Kalman Filter

Accelerometer Geodetic Seismogeodetic

250 Hz

Singly Integrate

Velocities

+

+

Clips in the near

field

No Static Offset No Static Offset Static Offset

Broadband

Magnitude

Saturation

Magnitude

Saturation

Cannot detect P

wave

No Magnitude

Saturation

Real-Time Seismogeodetic Station SIO5 – Mt. Soledad, La Jolla

GNSS Antenna/Radome

Monument

SIO MEMS

Accelerometer

Radio Antennas

Solar Panel

SIO MEMS Met Sensor

GNSS Equipment

Enclosures

Photo courtesy

D. Glen Offield

100 Real-Time Seismogeodetic Stations in the

Western U.S.: Candidates for EEW

A seismogeodetic “station” has a GNSS/GPS and at least one seismic instrument within 2-3 km, but preferably within meters.

Goldberg and Bock, JGR, 2017

Earthquake Early Warning: 2016 Mw5.2 Borrego Springs Earthquake

Goldberg and Bock, JGR, 2017

Pick P waves on

seismogeodetic velocities

derived from GPS

displacements and MEMS

accelerations

Extending Seismogeodesy to the Oceans: Local Tsunami Warning

Melgar & Bock, JGR, 2015

On-shore

seismogeodetic data

Tsunami Wave Data:

GNSS buoys

Pressure gauges

GNSS/A

Seismometers

Strainmeters

Seafloor

deformation

Earthquake Models

Topography

Bathymetry

Tsunami Prediction

+

+

Satellite

Orbits

&

Clocks

Data

Gathering

Data Gathering

Precise

Point

Positioning

Hierarchy

of Warnings

Data and Warnings to

Tsunami Warning Centers

Director’s Report:

CRTN, Epoch Update & Dynamic Datum

Questions?