Nationwide Differential GPS (NDGPS) Real-Time Data Streaming

1. Nationwide Differential GPS (NDGPS) Real-Time Data Streaming Federal Geodetic Control Subcommittee Silver Spring, MD January 10, 2012 Timothy A. Klein Senior Policy Advisor/RITA NDGPS Coordinator Timothy.Klein@dot.gov NDGPS@dot.gov

2. GPS-Based Applications are Critical to Major DOT Initiatives Aviation – NextGen • Reliable and accurate positioning worldwide • Reduced delays • More fuel-efficient routes • Increased system capacity with enhanced safety Rail – Positive Train Control • Reduced probability of collisions • Increased efficiency and capacity • Rapid rail structure and conditioning mapping ITS/Connected Vehicle • Increased mobility and reduced environmental impact Enable crash prevention among vehicles and between vehicles and infrastructure

3. NDGPS Applications Partners • Department of Commerce • Continuously Operating Reference Stations • Severe Weather Forecasting – water vapor • estimates to national weather models • Space Weather Monitoring – free electron mapping • Federal Resource Agencies (USDA, NPS, USGS) • One meter real-time positioning and navigation • Fire management and safety • Survey and mapping; GIS applications • State, County and Local Governments, Private and Non-Profit Sectors • Lands, parks and environmental resources management • Precision agriculture • Mining and other resource management

4. NDGPS Program Status • Inland (DOT) Tower Recapitalization • Upgrade reference stations/integrity monitors/antenna • Install IP-based operations system • Upgrade transmitters • Receiving FY12 funding to begin • Buildout Unlikely • No DOT support for construction funding • Strong support for O&M and recap • USCG Status • Reduced requirements; budget concerns • Looking at future of broadcast system; timing backup? • FY12 study of NDGPS real-time accuracy estimates and measurements • “Market Reality” Status • Limited interest in commercial use of broadcast signal • Few DGPS board manufacturers; firms leaving the field • No new program budgeting for civil positioning/navigation

5. Potential “Best Uses” of a National Asset • Strengthening the Asset for 10 -15 Years • But will the broadcast mission last that long? • Is there a role for streaming NDGPS observables, with or without broadcast? • Whom could this investment serve? • Strongest Continuing User Group – CORS User Community • Robust, service availability-guaranteed CORS sites • 23% of CORS solutions use an NDGPS-CORS site • Data streaming in RTCM format test-proven (1cm horizontal, 3cm vertical) • Would prefer to maintain broadcast capability • Continuing requirement - transportation services • Can streaming data meet dynamic accuracy requirements? • Desire to complete HA-NDGPS broadcast prototype • Questioning requirement – Coast Guard/maritime • Can streaming data meet positioning and navigation requirements? • Can streaming data improve harbor safety?

6. NGS Streaming of CORS Data (including NDGPS) Single Baseline of 55 kms to Streaming Station Using a Trimble GeoXH 2008 Using Trimble R8 Model 3 GNSS

7. NGS Streaming of CORS Data (including NDGPS) • Pluses: • Free • Easy to use with receiver built in support • Only one GPS receiver required • Provides real-time, dual-frequency RTK positioning. • Some streaming sites provide GLONASS data. • Open source so other entities can produce a value-added product • Minuses: • Requires cell phone coverage and an unlimited data cell plan which can be expensive • Data link drains the cell battery in relatively short amount of time (about an hour so external power is recommended ) • Lat/Long reference frame is ITRF. This can add an unnecessary level of complication to integration with existing NAD83 referenced data. • Single baseline • The number of streaming sites is limited at this time