1. GAO Report on GPS “Significant Challenges in Sustaining and Upgrading Widely Used Capabilities” Presented on 30 April 2009 to Subcommittee on National Security and Foreign Affairs, Committee on Oversight and Government Reform, House of Representatives Released to the public on 8 May 2009 http://www.gao.gov/new.items/d09325.pdf

2. Context 11 of 46 papers at US Hydro 2009 depend upon the assumption that GPS is a reliable infrastructure, that can only get better. This assumption may be too optimistic

3. Subsystem Status (Sept 2008) Riedesel, CGSIC48 [05] Sept 08 33 in orbit 21 okay 4 unhealthy 7 last clock

4. GPS Status On May 14, 2009 there are 30 usable GPS satellites. 18 of these have exceeded their design life. SVN49 was launched on March 24, 2009 but is not yet usable. The last Block IIR-M satellite is scheduled for launch in August 2009. The first Block IIF satellite is scheduled for launch in November 2009, 3 years late. Between 2010 and 2023, 11 more Block IIF, 8 Block IIIA, 8 Block IIIB, and 16 Block IIIC launches are scheduled. ftp://tycho.usno.navy.mil/pub/gps/gpstd.txt

5. PDOP map for 17 May 2009

6. 18-satellite outage map

7. GPS signal evolution Previous launches Launches from Dec 2005

8. GPS Ground Station Upgrades CapabilityOriginal Plan ActualNow Expected Months Delay Block IIRM & IIF Command & telemetry Sept 2005March 200830 L2C, M & L5 signals Sept 2007Sept 2012 to Sept 2013 60-72 Military use of modernized signal Army, Navy, Marine Corps fully equipped with modernized GPS equipment by 2025, 12 years after IOC - 18th modernized launch (2013) 10 years after FOC - 24th modernized launch (2015)

9. IIF Procurement problems Significant technical problems (not yet solved) New acquisition policy relaxed oversight and quality inspections, introducing problems Contractor changed locations, teams, and ownership several times (7 project managers so far) Requirements creep 3 years behind, 120% over budget

10. Block III acquisition Divide into 3 evolutionary phases –IIIA - stronger military signal, L1C –IIIB - crosslinks –IIIC - improved military antijam Two civil payloads for IIIB, IIIC –Distress Alerting Satellite System (DASS) –Satellite Laser Ranging retromirrors GAO report judges planned delivery schedule too optimistic, and predicts 2 year delay

13. International alternatives

14. http://www.glonass-ianc.rsa.ru/pls/htmldb/f?p=202:20:11394786619100357095::NO:::

15. Bottom line “For civil and commercial users, one possible impact of a smaller GPS constellation could be an increased use of other positioning, navigation and timing (PNT) services, including those expected to be offered through Europe’s Galileo system...” Department of State asks for higher priority for US expert participation in international PNT activities, to ensure compatibility with GPS is maintained.