Foundation CORS Underpinning a New Positioning Framework Daniel

Foundation CORS: Underpinning a New Positioning Framework Daniel Roman and Kevin Choi

Outline • Foundation CORS (FCORS) – Improve multi-GNSS coverage in North America – More IGS station options for future ITRF modeling – Provides more control to Reprocessing of CORS • New Reference Frames in 2022 – Four total tied to ITRF model – EPP & IFVM – Positions tied to GNSS and not passive control August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 2

Historic Reference Frame Sites on the North American Plate August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 3

Site Agency Domes # Location Begin Status Constellati on Colocation ALGO NRCan 40104 M 002 ON, CAN 1991 Op. GPS, GLO, GAL SLR DRAO NRCan 40105 M 002 BC, CAN 1991 Op. GPS, GLO, GAL Seismo. YELL NRCan 40127 M 003 NT, CAN 1991 Op. GPS, GLO, GAL DORIS FAIR JPL 40408 M 001 AK, USA 1991 Op. GPS only None GODE JPL 40451 M 123 MD, USA 1993 Op. GPS only SLR, VLBI GOL 2 JPL 40405 S 031 CA, USA 1997 Op. GPS only None MDO 1 JPL 40442 M 012 TX, USA 1993 Op. GPS, GLO SLR NLIB JPL 40465 M 001 IA, USA 1993 Op. GPS only VLBI PIE 1 JPL 40456 M 001 NM, USA 1992 Op. GPS, GLO VLBI BRMU NGS 42501 S 004 Bermuda 1993 Op. GPS, GLO None WES 2 NGS 40440 S 020 MA, USA 1993 Non-Op. GPS, GLO VLBI THU 1 DNSC 43001 M 001 Greenland August 03, 2017 Session G 01 -6 1995 Decomm. GPS only Jan. 2003 Joint Assembly of IAG-IASPEI in Kobe, Japan Replaced by JUly 30 - August 4, 2017 THU 3 None 4

Reference Frame Station Requirements • • Geographic Distribution Surroundings Geologic/Tectonic Monumentation Site Survey Operation Instrumentation Co-location Metadata/Analysis August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 5

Current Status and Future Plans BRSG FLF 1 August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 6

FCORS • Additional options for future ITRF models – Select sites to maximize coverage and co-location – Consideration for global coverage and US needs • More ties to regional (SIRGAS) & global frames (UN-GGRF) • Control for reprocessed CORS coordinates • QA/QC of CORS in OPUS-Net – Uses IGS stations (FCORS) to evaluate CORS • CORS/FCORS then provide access to Frames August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 7

New US Frames in 2022 • Will be tied to most recent ITRF – Epoch date TBD – likely 2020. 0 – Four Frames: North America, Pacific, Caribbean, and Mariana • • • At epoch date, all frames identical to ITRF Then each frame rotates about an Euler pole Velocity models describe motion in frame Access to the four frames via OPUS tool Versioning of coordinates based on models August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 8

NSRS Modernization: Four New Frames The Old: NAD 83(2011) NAD 83(PA 11) NAD 83(MA 11) The New: The North American Terrestrial Reference Frame of 2022 (NATRF 2022) The Caribbean Terrestrial Reference Frame of 2022 (CATRF 2022) The Pacific Terrestrial Reference Frame of 2022 (PATRF 2022) The Mariana Terrestrial Reference Frame of 2022 August 03, 2017 Session G 01 -6 (MATRF 2022) Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 9

Four Frames/Plates in 2022 NATRF 2022 MATRF 2022 PATRF 2022 August 03, 2017 Session G 01 -6 CATRF 2022 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 Image from Snay 2003 10

Replacing the NAD 83’s • Three plate-(pseudo)fixed frames will be replaced with four plate-fixed reference frames – N. Amer. , Pacific, Mariana, Caribbean(new!) • Remove long-standing non-geocentricity of NAD 83 frames • All four : identical to ITRFxx at a TBD epoch – 2020. 00? • All four : differ from ITRFxx by plate rotation only – Updated Euler Pole determination for rigid plate only August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 11

Each frame will get 3 Euler Pole Parameters (EPP) - Euler Pole Latitude - Euler Pole Longitude - Rotation rate (rad/yr) Used to compute time-dependent TRF 2022 coordinates from timedependent ITRF coordinates. August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 12

Intra-Frame Velocity Model • Euler pole rotation accounts for motion in “stable” areas • Remaining motion accounted for with IFVM – This is still very much “TBD” – Simple case is gridding CORS and other c-GNSS – Could be a complicated geophysical model – Will account for 3 D time varying motions – Could apply across plate-boundary (e. g. , California) August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 13

Discussion and Summary • Foundation CORS (FCORS) – More stations available to IGS for choice – Used to adjust the broader CORS Network – Provides better ties to regional and global models • New Frames to be established in 2022 – Four ITRF-based frames – Euler pole parameters define plate motion – Intra-Frame Velocity Models describe remaining motion in a frame August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 14

Questions? Daniel R. Roman Chief Geodesist National Geodetic Survey August 03, 2017 Session G 01 -6 Joint Assembly of IAG-IASPEI in Kobe, Japan JUly 30 - August 4, 2017 15