S. California Real Time GPS Networks Yehuda Bock CSRC Semi-Annual

S. California Real Time GPS Networks Yehuda Bock CSRC Semi-Annual Meeting PG&E, Oakland May 16, 2003

SCIGN OCRTN

OCRTN Network baselines

OCRTN Overview Streaming raw high-rate (1 sec) GPS data from 10 (soon 12) continuously operating reference sites (CORS) to central facility in Santa Ana. These data are available to anyone in raw (MBEN) or RINEX formats for postprocessing. Generating and making available real-time data (1-2 s latency) via the wireless Internet to anyone at no cost (free) for real-time kinematic (RTK) surveying and various forms of dynamic positioning in Orange County. Some Uses Public and Private Surveying ** Precise GIS ** Emergency Response Police Work Intelligent Transportation ** Aircraft Navigation Bridge and Dam Deformation ** Geophysics ** Weather Forecasting ** ** Currently being used or evaluated

Current Network Architecture

Typical OCRTN RTK Equipment Ashtech Z-Xtreme receiver Ashtech Geodetic-IV antenna TDS Ranger data collector Raven II CDPD modem 2-meter bi-pod

RTK Receivers operating with OCRTN Ashtech – Ranger (TDS Survey Pro) Leica – System 500 Z-Extreme Z-Surveyor SR530 Trimble – TSCE & TSC1 5700 4800

CDPD Wireless Internet Cellular Digital Packet Data – Digital data transmission technology developed for cellular networks. Using a CDPD modem, mobile users connect to the Internet through a CDPD provider. Uses TCP/IP In Orange County, AT&T is the provider. Service charge is 54.99 per month, unlimited use. Operates at 19,200 Kbps (realistically 14,400 Kbps). Latency is 1-2 seconds Higher bandwidth CDMA technology is available from Verizon and Sprint and is being evaluated.

GPS Seismology and the Denali EQ Experience with low rate (30s) SCIGN data after the 1999 Hector Mine Earthquake in southern California indicated that detecting seismic waves with GPS data was feasible. The 2002 Denali earthquake in Alaska provided us the first opportunity to test this concept with high rate (1s) SCIGN/OCRTN data.

(rms 2.8 mm) (rms 2.6 mm)

Focus of Real-Time Upgrades Western Riverside & SD Counties Diamond Valley Lake Parkfield

HPWREN and RoadNet Network Topology Real-time upgrades will take advantage of high-speed communications infrastructure developed at UCSD’s Supercomputer Center (SDSC) and Scripps for seismic and other scientific data: HPWREN and ROADNet Projects. New Site at Pine Cove

Riverside County Real Time Network Funding is now available from NASA SENH, Riverside County Department of Transportation, Riverside County Flood and Water Conservation District, HPWREN and RoadNet to move forward to upgrade SCIGN stations in Western Riverside County, possibly with some sites in neighboring San Bernardino, San Diego, and Imperial Counties. Goal: GPS/Seismic Displacement Meter

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