This report is submitted to the Senate Committee on Armed Services and the House Committee on National Security as directed by the National Defense Authorization Act for Fiscal Year 1998. This report is prepared by the Department of Defense (DoD), in consultation with the Departments of State, Commerce, and Transportation (DOT).


The Global Positioning System (GPS) is rapidly emerging as a key information technology that offers a broad range of benefits to both military and civil users. As it is incorporated into numerous military and civil infrastructures, there is an ever increasing reliance on GPS. Increased military and civil reliance on GPS poses unique challenges since the objectives of these groups sometimes conflict. While balancing the diverse needs and interests, the US Government (USG) is actively promoting GPS and US augmentations to GPS as an international standard for positioning, navigation, and timing.


The DoD and the Air Force fully intends to maintain a 24-satellite constellation for the duration of the program. Currently, there are 27 fully functional GPS satellites on orbit. In general, the satellites are exceeding expectations with 13 satellites past their original mean mission duration. All 28 satellites of the first operational Block II/IIA satellites have been launched. One Block IIR satellite is currently on orbit. A total of 11 of the 21 Block IIR replenishment satellites have been delivered by the contractor and accepted by the Air Force. Four Block IIR satellites are in storage at the launch site at Cape Canaveral, Florida awaiting launch which is scheduled for April 1999. Thirty-three Block IIF satellites are currently planned to be procured with the first Block IIF launch scheduled to occur in 2003. In short, GPS is a stable, healthy constellation.


Military Requirements

Military positioning, navigation, and timing (PNT) requirements are validated by the Joint Requirements Oversight Committee (JROC) and are reflected in the Chairman of the Joint Chiefs of Staff (CJCS) Master Positioning, Navigation, and Timing (PNT) Plan. The 1998 version of this document is based on the Chairman's future operational perspective as stated in Joint Vision 2010 (JV 2010) which provides the conceptual framework of the future battlespace. In the future, "Information Dominance" achieved through greater precision of positioning, velocity, and timing information will be key to maintaining superior tempo and surprise. The CJCS Master PNT Plan clearly delineates GPS as the centerpiece of the DoD's positioning, navigation, and timing system architecture for the foreseeable future.

Experience with GPS to date has identified a number of operational limitations. These limitations have been documented as operational need in a Mission Needs Statement (MNS) titled For the Operational Protection and Prevention of Global Space-Based Navigation Systems which was validated by the Joint Requirements Oversight Council (JROC) on March 26, 1996. The MNS specifies a need to develop and acquire "effective capabilities" to deny adversarial use of GPS without hindering US force's ability to operate with the system and without disrupting civil use outside an area of military operations. In response to these operational requirements, the DoD initiated the Navigation Warfare (Navwar) effort in 1996. The Department is finalizing a Navwar Analysis of Alternatives for review in early 1999. This will set the stage for military GPS modernization activities to be conducted over the next several years. It will also be the military input into the overall GPS 1999 modernization decisions for both military and civil users.

Federal Radionavigation Plan (FRP)

The FRP provides a consolidated statement of USG plans for Federally-provided radionavigation systems. Although GPS is the foundation of the USG's planned radionavigation system mix for the foreseeable future, the FRP acknowledges that GPS does not satisfy the requirements of all radionavigation system applications. Consequently, the FRP describes a number of augmentations to GPS to meet the stringent needs of particular user groups.

Aviation Requirements

The current US National Airspace System (NAS) relies on a ground-based network of navigation aids. As capacity demands increasingly stress the system, the Federal Aviation Administration (FAA) has been evaluating alternative technologies to support NAS modernization. GPS has been identified as the pivotal technology to support the future NAS system architecture.

Today, the GPS Standard Positioning Service (SPS) satisfies certain aviation navigation requirements. However, it does not meet the integrity, availability, and accuracy requirements for domestic en-route through precision approach. To address these limitations, the FAA is developing a Wide Area Augmentation System (WAAS) and a Local Area Augmentation System (LAAS). The WAAS will afford the NAS architecture the required levels of integrity, availability, and accuracy to support primary navigation and safety requirements for en-route through Category I precision approach. The LAAS will support Category II/III precision approaches. Together, GPS augmented by WAAS and LAAS will establish the foundation for the future global aviation architecture.

Maritime Requirements

The GPS SPS also supports many maritime navigation requirements including open ocean operations and coastal navigation. However, GPS is not capable of meeting the more stringent navigation requirements for harbor approach and entrance, and inland waterways. To satisfy these requirements, the United States Coast Guard (USCG) has developed and implemented a land-based differential GPS (DGPS) network. This system became operational in January 1996 and should be fully operational in 1999. It provides complete coastal coverage of the continental US and to selected portions of Hawaii, coastal Alaska, Puerto Rico, and major inland rivers. This maritime network has given the USCG the necessary tools to ensure enhanced safety and management efficiency for all its areas of responsibility within the US.

Civil Land Requirements

Land users are in the early stages of defining requirements. GPS has the potential to satisfy many emerging land-based positioning and navigation needs. The DOT is developing a Nationwide DGPS (NDGPS) system to augment GPS for specific highway, rail, and transit uses. The NDGPS system is an extension of the Coast Guard's maritime DGPS system architecture and is expected to be fully operational in 2003.

Civil Space Requirements

GPS space applications include onboard navigation, orbital management, attitude determination, scientific data collection, and data post processing analysis. Today, several NASA programs are evaluating GPS for spacecraft position determination. Specifically, the TOPEX/POSEIDON, launched in August 1992, is using a high-accuracy, dual-frequency GPS flight receiver on an experimental basis. In addition, NASA plans on fully implementing GPS as an operational system on future Space Shuttle missions as well as the International Space Station.

Civil Non-Navigation Requirements

In addition to traditional navigation users, several new user groups are becoming increasingly reliant on GPS information. Specifically, GPS is used for: surveying, mapping, geophysical determination, meteorology, mining, agriculture, off-shore oil exploration, banking, emergency response, telecommunication networks, power grid management, and timing.


Due to the expanding worldwide use of GPS with its high accuracy, continuous global availability, and relatively low cost, increased exploitation by foreign militaries will occur, particularly in weapons delivery applications. SA is currently the only effective means available to the US to control access to the full GPS accuracy.

The Presidential Decision Directive (PDD), NSTC-6, was released in March 1996 articulating the President's GPS Policy in balancing military and civil GPS needs over the next decade. PDD NSTC-6 stated that it is the USG's "intention is to discontinue SA use within a decade in a manner that allows adequate time and resources for our military forces to prepare fully for operations without SA." A key factor in determining when to discontinue the use of SA is the DoD's ability to deploy an alternative military capability. As described earlier, new military requirements are being documented for review in 1999. Among the emerging military requirements is the need to deny adversarial use of GPS. Therefore, it is premature to include in this report a firm date for discontinuing SA. Once the requirements are validated, the DoD will develop, procure, and deploy the new operational capabilities, and a timeline will be established for discontinuing SA by 2006 in compliance with the President's GPS policy.


Civil, Commercial, and Scientific Activities

Along with the goal of strengthening and maintaining our national security, the 1996 Presidential policy defined the US goals for civil, commercial, and scientific uses of GPS. The Departments and agencies are working with their respective international counterparts to achieve these goals. To date, international discussions have focused on establishing GPS as a core component of any future Global Navigation Satellite System (GNSS) and the necessary infrastructure to support a global seamless architecture. Many political, institutional, and technical issues must be resolved before this architecture is realized. The US continues to be an active initiator, participant, and facilitator internationally in defining the future GNSS architecture.

The USG has offered GPS and its augmentations to the International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO) as candidates for the future GNSS architecture. As the international standards bodies for their respective communities, both the ICAO and the IMO have accepted the US offer. In support of international acceptance of GPS, the FAA is actively working within ICAO to establish GPS as a standard that can be accepted internationally as part of the future GNSS architecture. Similarly, the USCG continues to be a driving force in IMO activities. To date the USCG has been successful in obtaining acceptance for the US DGPS system as the model for additional future systems. As a result, the IMO is considering the USCG developed DGPS format as the world standard for local area GPS augmentations to meet worldwide maritime user needs. Once adopted by the IMO, this signal format will become the first operational, international civil augmentation standard for GPS.

Military International Activities

US-Allied interoperability will be essential for future multinational operations with GPS playing an important role in that interoperability. The US military is moving forward towards full implementation of GPS as are many of our allies. As a result, cooperative GPS efforts are growing. The DoD's Navwar Advanced Concept Technology Demonstration (ACTD) and future joint trials and testing will act as the focal points for expanded cooperative efforts.

Over the past 18 months, the US has updated NATO and Australia on the ACTD Program. As a result, a number of countries have expressed interest in becoming involved in this effort, and some have initiated their own Navwar efforts that are similar in scope and technological sophistication to that of the US. The DoD is currently working with these nations to develop the appropriate Memoranda of Agreement (MOA) to ensure continued interoperability.

In addition to the Navwar Program, DoD has conducted several joint testing efforts with many of our allies. The majority of these tests have been with handheld military receivers. The most extensive testing has been with the NATO nations, specifically, Norway, France, Germany, Denmark, Canada, the Netherlands, and the United Kingdom. Similar tests are being conducted with Australia. These tests focus on: electromagnetic interference and compatibility, jamming and spoofing susceptibility, foliage attenuation, extreme operational environments, and special applications analysis. These efforts will continue to ensure that DoD and its allies maintain a high level of interoperability.


Under the leadership of the State Department, the US has held bilateral consultations with the European Union (EU) and the Government of Japan in an effort to establish GPS as an international standard for positioning, navigation, and timing. These consultations have been a prelude to the drafting of agreements that will promote the following shared objectives:

To meet the above objectives, the US and EU principals met in Brussels in May 1998 and in Washington, DC in July 1998. Several specific areas were identified to be explored in greater detail, including: the nature of cooperation, service guarantees, spectrum protection, interoperability, safety certification, civil-military interface, and liability. The next consultation with the EU is scheduled for mid November 1998.

Additionally, the USG negotiated a Joint Statement on GPS cooperation with the Government of Japan. On September 22, 1998, President Clinton and Prime Minister Obuchi signed that statement. The statement addresses cooperative activities to: promote GPS as an international standard, prevent misuse of GPS, promote compatible operating standards, build awareness of the need for adequate GPS radio frequency allocation, and encourage trade and investment in GPS equipment. The State Department has also initiated an international outreach program describing the ways foreign economies and infrastructures can benefit from GPS. In a related area, the State Department has sponsored discussions with Russia on GPS and the Global Orbiting Navigation Satellite System (GLONASS) issues. The US provided Russia with a list of tentative topics for the next round of discussions, as well as possible meeting locations and times. The next meeting with the Russian Federation has not yet been scheduled.

Spectrum allocation and protection continues to be a critical issue affecting GPS and its future as an international standard. The State Department is leading several key efforts to ensure that the GPS spectrum is afforded the appropriate safeguards at the upcoming World Radio-Communications Conference in 2000 (WRC-00). The State Department is leveraging off the National Telecommunications and Information Administration (NTIA) and the Federal Communications Commission (FCC) technical studies to provide the technical basis and justification for US proposals at WRC-00. These studies will provide the International Telecommunications Union (ITU) with technical information that will determine how the future frequency spectrum is allocated and protected for space-based systems.


Appendix A of The President's Commission on Critical Infrastructure Protection Final Report, (October 1997) highlighted the potential vulnerabilities of GPS and its augmentations to disruption and interference. Specifically, the report stated:

As a result of the report, Presidential Decision Directive 63 directed that "the DOT, in consultation with DoD, shall undertake a thorough evaluation of the vulnerability of the national transportation infrastructure that relies on GPS. This evaluation shall include sponsoring an independent, integrated assessment of risks to civilian users of GPS-based systems, with a view to basing decisions on the ultimate architecture of the modernized NAS on these evaluations." The DOT has chartered the Volpe National Transportation Systems Center to study options for developing a plan for protecting the national transportation infrastructure. The Volpe Center will also conduct field tests to validate technical aspects of this work. The final report is due to be released in 1999 and will include:

Federal Aviation Administration: NAS Security Program

Presidential Decision Directive 63 also directed that "the Federal Aviation Administration shall develop and implement a comprehensive National Airspace System Security Program to protect the modernized NAS from information-based and other disruptions and attacks." The FAA is working with the Air Transport Association (ATA) and the Aircraft Owners and Pilots Association (AOPA) to perform an independent GPS risk assessment. This study will determine the ability of GPS, WAAS, and LAAS to serve as the only navigation system required for aircraft operation within the NAS. The final report is expected in early 1999.


National and Regional Security

An assessment of military modernization technologies available to upgrade weapons systems illustrates the growing impact that GPS is having on regional and national security interests. Today, nations are evaluating alternatives to support military modernization in an attempt to strengthen their forces. Information technologies are being increasingly considered as part of that modernization effort. Open source literature clearly shows that GPS is now considered by military hardware manufacturers as a key information technology that can support many of these modernization efforts.

GPS performance in worldwide operations and the need to modernize a military infrastructure with a limited budget has driven many nations to incorporate GPS into weapon systems. These governments are either striving to reach parity with regional neighbors or tilt the balance of power in their favor. The rationale for using GPS is threefold. First, the USG has publicly guaranteed the global availability of the SPS free of any direct user charges for the foreseeable future. Second, the commercial marketplace offers a variety of GPS receivers that are extremely accurate and affordable. Third, the US military's growing reliance on this technology for daily operations ensures that the system will be available for use on a worldwide basis.

GPS is rapidly becoming a critical information technology equally applicable to both military and civil activities. As GPS becomes more deeply embedded into the economic and industrial base of the US, its protection, sustainment, and modernization become critical issues within national security policy development and implementation. In addition, its continued exploitation for military modernization globally by potential adversaries necessitated the development and employment of capabilities to counter this threat. The DoD is currently working to address this situation in its Navwar activities. Once Navwar is fully implemented, US national and regional security objectives will be maintained. Until then, US interests are increasingly threatened.

Economic Competitiveness of US Industry

Like the Internet, GPS is an increasingly critical element of the global information infrastructure and its sustainment is vital to US competitiveness in the global marketplace. The commercial use of GPS spans a broad range of business areas and has a significant impact on the nation's economic competitiveness in terms of revenues, productivity, and new business development.

Revenue Growth

According to Commerce Department estimates, annual sales of GPS goods and services reached $2.85 billion worldwide in 1997 and could exceed $16 billion by 2003. Currently, the US leads the world in GPS related sales with an approximate one-third market share. US market sectors exhibiting the strongest revenue growth include the automotive, tracking, recreational, and surveying businesses. In the automotive sector, GPS receivers have been tied to electronic mapping systems to provide directions, track and manage vehicle fleets, facilitate emergency roadside assistance, and recover stolen vehicles. Worldwide demand for GPS-based vehicle navigation systems is expected to grow from $900 million in 1997 to $4.7 billion by 2003. There is significant opportunity for US growth in this area.

GPS technology is being used to track everything from packages to people and to enhance the performance of many systems, including mobile telephones, public transportation systems, and search and rescue emergency services. The worldwide market for GPS-based tracking services is surging from $280 million in 1997 to $3 billion in 2003. Consumer uses of GPS equipment are expanding daily, with users ranging from recreational boaters and fishermen to hikers and golfers. As receiver costs continue to drop, the recreational market can be expected to grow from $560 million in 1997 to $3.8 billion by 2003. The survey and mapping industry, with its need for high precision, has given rise to a significant market for differential correction equipment offering centimeter-level, real-time measurements. The market for GPS surveying equipment and services is expected to expand from $530 million in 1997 to $2.5 billion worldwide by 2003.

Productivity Enhancement

GPS technology is replacing traditional methods of doing business, enabling users to reduce labor, lower costs, accelerate or automate processes, increase output, and enhance service quality. Such productivity enhancements are difficult to quantify but clearly strengthen the nation's economic competitiveness. In the transportation arena, GPS technology is improving the speed and efficiency of taxicabs, trucks, and public buses. It allows aircraft and ships to optimize routes, improving delivery times and saving fuel. It also enables better management of aircraft at airports, ships in waterways, and cars at rental agencies. GPS-enabled cargo vessels can gauge exact distances to the harbor floor and safely increase cargo loads. An extra foot of vessel depth in the water can translate into $36,000 to $288,000 of cargo.

For surveyors, GPS techniques have increased productivity 100% to 300% and dropped the average cost of a control survey point from $10,000 in 1986 to $250 in 1997. The digital maps or geographic information systems (GIS) which enable all value-added applications of GPS are themselves dependent upon GPS surveys to accurately reference objects in the database. The $1.2 billion GIS industry, which is expected to triple by 2000, would not be so thriving if it relied on traditional survey techniques.

GPS systems are being used to automate bulldozing and blasting machinery at open pit mines and provide real-time updates of mining progress. At one Wyoming coal mine, use of GPS has led to reduced labor costs, increased output, and a safety record that is four times better than that of the average US coal mine. GPS based machine control also benefits the agriculture industry, which can precisely apply fertilizers and pesticides, thus reducing material costs. GPS systems also help farmers level fields to minimize water and chemical runoff, saving resources and protecting the environment. Studies suggest that "precision farming" methods could reduce chemical costs from $24 to $20 per acre while increasing crop yields by $0.50 to $7.50 per acre.

New Business Development

From 1992 to 1997, the number of firms identifying themselves as "GPS related" in an annual magazine survey nearly tripled. US entrepreneurs are capitalizing on the unique capabilities of GPS and the diminishing cost of technology to create entirely new lines of business. The precise GPS time signal is now being used to calibrate computers, synchronize telecommunications networks, stamp financial transactions, and manage power grids. GPS information is also being utilized to gauge distances for golfers, provide handheld tour guide services, enable intelligent vehicle systems to improve highway safety and efficiency, track space vehicles, monitor railroads, and assist the physically challenged. Further, GPS is improving public safety by providing firefighters, hospitals, and law enforcement agencies with innovative tracking and dispatch capabilities that speed response, maximize efficiency, and save lives. Commercial GPS applications and markets are expected to continue to proliferate resulting in increased US economic activity for both receiver manufacturers and value added service providers.


Today, GPS is vital to both the future of US military operations and the evolution of many national infrastructures. The GPS system is continuing its expansive growth into both traditional and nontraditional applications. The uniqueness of providing continuous, highly accurate positioning, navigation, and timing information on a global scale ensures that GPS will become an increasingly vital element in the information age.

As the foundation for DoD's information architecture, GPS will translate the conceptual template of Joint Vision 2010 into a warfighting reality in the 21st century. At the same time, its global access and availability will increasingly challenge the DoD's ability to implement and employ assets and capabilities in an information dominated environment.

From a civil perspective, the rapid growth in GPS use demonstrates its ever increasing significance in civil, commercial, and scientific applications. GPS will become the foundation for a myriad of global architectures, networks, and infrastructures. The Transportation, State, and Commerce Departments are leading the way in establishing GPS as an integral component of the global marketplace. GPS is rapidly emerging as an essential element of any evolving information-based system or infrastructure that requires extremely accurate positioning, navigation, or timing information.

In support of US national objectives, the USG is working to ensure that GPS is accepted as an international standard (military and civilian) and that US industry remains a leader in the development, implementation, and utilization of this important technology. However, these national objectives can only be realized through stable management and funding of the GPS system both today, and in the future.

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