GAO Report on GPS

“Significant Challenges in Sustaining and Upgrading Widely Used Capabilities”

Presented on 30 April 2009 toSubcommittee 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

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

Subsystem Status (Sept 2008)

Riedesel, CGSIC48 [05] Sept 08

33 in orbit

21 okay

4 unhealthy

7 last clock

PDOP map for 17 May 2009

18-satellite outage map

GPS signal evolutionPreviouslaunches

Launchesfrom Dec 2005

GPS Ground Station UpgradesCapability Original

Plan

Actual Now Expected

Months Delay

Block IIRM & IIF Command & telemetry

Sept 2005 March 2008 30

L2C, M & L5 signals

Sept 2007 Sept 2012 to

Sept 2013

60-72

Military use of modernized signalArmy, 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)

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

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

International alternatives

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

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.