Official U.S. government information about the
Global Positioning System (GPS) and related topics
U.S. Statement from COPUOS
S&T Subcommittee
February 10, 2011
The following remarks were delivered by the U.S. representative to the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) in Vienna, Austria.
Statement by the United States Representative, on Agenda Item 10, Recent Developments in Global Navigation Satellite Systems
Mr. Chairman, the U.S. Global Positioning System (GPS) in 2010 once again maintained its reputation for reliability and accuracy. The constellation modernization program continued to progress as the first new Block IIF satellite was launched and is now operating normally, broadcasting a new civil signal, L5, in addition to other civil signals: L2C and L1 C/A. The constellation is being reconfigured to an expanded 24+3 slot constellation to provide better coverage and availability around the world. The United States published a new Space Policy in 2010 which reaffirms long standing and stable U.S. policy on space-based navigation. Finally in 2010 the United States continued its diplomatic efforts on a multi-lateral and bi-lateral basis to support compatibility, interoperability and transparency among current and future space-based positioning, navigation, and timing (PNT) providers.
As of November 29, 2010, GPS had 32 operational satellites in orbit to ensure a baseline constellation of 24 satellites. Eight of the Block IIR-M and one new Block IIF satellites are broadcasting a second civil signal called L2C. The IIF satellite is also broadcasting a new civil signal at L5, which eventually will be used for safety-of-life applications. Three additional satellites are in residual status and could be re-activated if one of the currently operational satellites experienced a sudden breakdown.
The GPS constellation is performing at exceptional accuracy levels -- the one year performance as of July 2010 provided a user range error of one-half a meter (.5 meter), the best ever. The reliability of the constellation has been enhanced by solid performance from the Block IIR and IIR-M satellites which have solar array/power capacity that far exceeds the specified mean mission duration and there have been no clock failures in these satellites to date. The first Block IIF satellite was set healthy in August 2010. Eleven more Block IIFs are in the pipeline with satellite vehicles (SVs) 2-5 already in production. The next IIF launch is scheduled for June 2011.
Our current procurement and launch strategy has led to more SVs on-orbit than the minimum required to maintain our basic 24 satellite constellation. The United States can reliably keep its basic 24 slot constellation filled while having other satellites available to move into three auxiliary slots, resulting in a 24+3 expanded configuration. This expanded 24+3 configuration, which will be fully achieved by June 2011, will improve performance, increase robustness to failures, and assure integrity and accuracy. The United States can always reconfigure back to the basic 24 SV constellation if required. The civil GPS performance commitment has been met continuously since December 1993 and we intend to keep this record intact in the future.
In June 2010 the United States published a new National Space Policy (NSP). The new Policy calls for an increased emphasis on international cooperation to promote the peaceful use of outer space in a wide range of areas. The United States will expand its work in the United Nations and with other organizations to address the growing problem of orbital debris and to promote "best practices" for sustainable use of space. The United States will also pursue pragmatic transparency and confidence-building measures to mitigate the risk of mishaps, misperceptions, and miscalculations. The new Policy reaffirms the longstanding and bipartisan U.S. policy that we are open to space-related confidence building and arms control concepts and proposals, provided they meet the rigorous criteria of equitability, effective verifiability, and consistency with our national security interests.
Under the new Policy, the United States intends to promote suitable commercial space regulations, international standards that promote fair market competition, and the international use of U.S. capabilities such as launch vehicles, commercial remote sensing services, and the civil services of the GPS. There are two major new ideas articulated in the NSP related to Global Navigation Satellite Systems (GNSS). First, the United States will also seek transparency in technical standards planned for civil service provision from non-U.S. GNSS, in addition to compatibility and interoperability of signals. Secondly the United States acknowledges that compatible and interoperable foreign GNSS may be used to enhance the service provided by GPS. Finally, the United States will pursue enhanced cooperative programs with other space-faring nations in space science, human and robotic space exploration, and in the use of Earth observation satellites to support weather forecasting, environmental monitoring, and sustainable development worldwide.
The United States compliments Italy and the European Union on the successful hosting of the Fifth Meeting of the International Committee on Global Navigation Satellite Systems (ICG-5) and the meeting of the related Providers' Forum in Turin, Italy, in October 2010. We commend the UN Office for Outer Space Affairs (UNOOSA) for its outstanding performance in assisting with the planning and organization of this meeting and for its continued support as the Executive Secretariat for the ICG and Providers' Forum. The United States was pleased with progress made on the ICG work plan. We continue to strongly support the principle of transparency for open services. That principle is "Every provider should publish documentation that describes signal and system information, policies of provision and minimum levels of performance for its open services." While some progress was made on this at ICG-5, the United States hopes for even more progress on transparency in the coming year. The United States continues to provide stable financial support to UNOOSA in support of GNSS related activities, including regional workshops and support to the ICG and Providers' Forum.
In addition to our multilateral efforts on GNSS related issues, particularly at the ICG, the United States has many productive bi-lateral relationships on satellite navigation issues. United States-Japanese cooperation on GPS-related issues has included regular policy and technical consultations since 1996. The United States congratulates Japan on the successful launching of Michibiki, its first Quasi-Zenith Satellite (QZS) in September 2010. The United States is pleased with the successful operation of QZS monitoring stations at Hawaii and Guam in support of Michibiki.
The United States and the European Community and its Member States continued cooperative work under the 2004 GPS-Galileo Cooperation Agreement. On July 30, 2010, the United States and the European Union (EU) and its Member States announced the conclusion of an initial phase of consultations affirming user interoperability and enhanced performance of combined GPS and Galileo receivers. A working group designed to enhance cooperation for the next generation GPS and Galileo completed an assessment of the global, combined performance for GPS Satellite-Based Augmentation System (SBAS) receivers using the European Geostationary Navigation Overlay Service (EGNOS) and the GPS Wide Area Augmentation System (WAAS) supporting safety-of-life applications. The results confirmed improved availability for a wide range of aviation services in both hemispheres and significantly improved robustness to GPS satellite outages. The working group also completed an assessment of receivers integrating planned interoperable GPS III and Galileo open civil services. The study compares GPS, Galileo, and GPS/Galileo combined performance for three receiver types using four study cases. The combination of GPS and Galileo services provided noteworthy performance improvements particularly in partially obscured environments, where buildings, trees or terrain block large portions of the sky. Dual-frequency receivers provide additional improvements in most environments. This study illustrates benefits expected from future broadband signals on GPS and Galileo and other future GNSS.
In conclusion, let me reiterate several key policy principles. The United States intends to continue improving GPS's accuracy and availability through improved satellite and clock performance, and an expanded constellation configuration. The United States is committed to keeping GPS as a central pillar in an emerging international system of Global Navigation Satellite Systems. As new systems emerge, signal compatibility and interoperability among GNSS, as well as transparency in the provision of open civil services are key factors in ensuring that civil users around the world receive the maximum benefit from GNSS applications. Therefore, the United States strongly supports international cooperation among current and future GNSS.
Thank you, Mr. Chairman.
