A recurring theme of this narrative has been the need to serve civilian users of navigation, timing, and positioning services while not compromising military priorities. The US Defense Department supports and manages GPS to provide military users with high-integrity, precise, and accurate signals. It also seeks to deny hostile forces or entities the means to use satellite signals for their own targeting or other military purposes. The initial model of civil-military use was anticipated from the start. Although the operation of the system is the responsibility of the Air Force, the current oversight of GPS is in the hands of a joint committee: the National Executive Committee for Space-Based Positioning, Navigation, and Timing. It is co-chaired by representatives from the Department of Defense and Department of Transportation, with members from seven other federal agencies or departments that have an interest in the system.1 It reports directly to the White House. The executive committee is a descendent of an Interagency GPS Executive Board, which President Clinton established in 1996, shortly after GPS became fully operational.
We see from the initial imposition of selective availability, its removal in 1991, followed by its re-imposition and then permanent removal in 2000—along with the emergence of differential GPS and the Wide Area Augmentation System—that the government’s management of civil access to GPS was not smooth. Added to all this, also unforeseen by GPS architects, was the integration of GPS with cell phone location capabilities, including assisted-GPS. The use of satellite navigation systems for automobiles and trucks, including turn-by-turn navigation systems and emergency services, was anticipated as a major civilian application. Finally, although GPS is not among the most significant apps found on a modern smartphone, its integration with mapping software, traffic management programs like Waze, electronic “yellow pages” (e.g., Yelp), and social location services contributes to the overall sense that the smartphone, now about a decade old, is a revolutionary piece of technology.
Apple is now one of the most profitable companies in the world. Many commercial services, including Uber, depend on GPS for their operation. The satellite systems on which these services and products depend are free: funded by US taxpayers and the governments of Russia, China, and the European Union. The satellites are needed not only for geolocation; cellular telephone services would be impractical without the timing information supplied by satellites. At one time in the early development of GPS there was talk of charging a fee for civil users, but it was deemed impractical.
The civilian use of GPS escaped the controls that the US military establishment hoped to impose on it, although it continues to pay for much of it. Like the sorcerer’s apprentice, the military turned on a spigot, which became a gusher that it could not turn off. This story has relevance to the debates among historians about whether technology is autonomous, socially constructed, or somewhere in between.2 In this instance, there was a clear progression from an early set of` alternative architectures, with differing orbits, coding schemes, frequency standards, and other parameters. By the mid-1970s these alternatives converged, resulting in the closure of the “black box” and the architecture initially conceived by Roger Easton and his colleagues at the Naval Research Laboratory (NRL). Air Force Col. Brad Parkinson had to convince his superiors in the Air Force that GPS was first and foremost a military system that could serve the Pentagon’s desire for better bombing accuracy. Yet the trajectory of GPS also veered off in unanticipated directions, including via two direct interventions by US presidents. In 1983, President Ronald Reagan assured the world of free availability of GPS signals for commercial navigation; in 2000, President Bill Clinton ordered the permanent setting of selective availability to zero. Neither president was knowledgeable of the technical issues related to navigation or satellites, but both recognized the geopolitical importance of the technology.
Historians of technology are familiar with this sequence of events. Donald MacKenzie’s analysis of ballistic missile guidance argues that increasing accuracy, driven by Charles Stark Draper at MIT, was not always in alignment with US policy toward nuclear deterrence. Likewise, Janet Abbate’s study of the origins of the Internet shows how designers of the Internet’s predecessor, the ARPANET, were taken by surprise at the emergence and rapid adoption of email, something they had not anticipated.3
Both GPS and the Internet owe their origins to military needs, and both took form during the 1970s. Both have become indispensable components to the infrastructure of a modern technoscientific society. Both rely on complex, cutting-edge technologies. Both are expensive to construct, operate, and maintain. Unlike GPS, funding for Internet hardware, software, and services comes from mostly commercial sources, with direct federal appropriations now only a small part. Unlike the Internet, GPS is largely invisible, and its importance and place in society are poorly understood by the public. The United States is involved with governance of the Internet and maintains its assertion of ownership, but the United States has from time to time had to remind everyone that it will not accept transfer of Internet governance to the United Nations or other international body.4 Debates over the future of the Internet are carried out in public, with other nations insisting on having their say.5 By contrast, GPS remains under tight US government control (see figure 21). Control of GPS was transferred from the Defense Department to the current civil-military executive committee, but further transfer of control, including to an international body, is unlikely. Writing in 1995, Bradford Parkinson remarked, “the civil problem is only partially resolved.”6 He made that statement in the context of Defense Department debates over how much accuracy civil users should be allowed to have. Subsequent developments have partially addressed the problem. But the civil-military problem remains in the foreseeable future.
Figure 21 Senior Airman Nayibe Ramos serves as a satellite system operator for the 2nd Space Operations Squadron, Schriever Air Force Base, Colorado, the headquarters of GPS operations. (Photo: US Air Force Airman 1st Class Mike Meares)
The Inventors of GPS
Priority disputes in the history of technology are not new. The question of who invented the digital computer was addressed by Earl Larson, a judge who presided over a patent dispute between two established computer manufacturers. His judgment, rendered in the fall of 1973, has not been accepted by all historians.7 Similar disagreements are found among historians regarding who were the “fathers” of the Internet, the inventors of the microprocessor, and most recently the inventor of email.8 In November 2016, Bradford Parkinson received the 2016 Marconi Award in recognition of his contributions to the development of GPS. Given a mandate by Malcolm Currie, the Undersecretary of Research and Engineering for the Defense Department, Parkinson led a group that defined the architecture for GPS that survives to the present day and serves as the model for the European, Russian, and Chinese systems.9 When, in 1993, the Collier Trophy was awarded to the “GPS Team,” the NRL was listed first.10 At the NRL, Roger Easton led a team that came up with nearly all of the parameters of the GPS architecture, with the exception of the Air Force’s coding scheme. Even more telling, the NRL demonstrated the feasibility of GPS through the design and orbiting of several Timation and NTS satellites.11 Pete Wilhelm at the NRL came up with a way to launch first-generation GPS satellites on refurbished Atlas-F rockets. That was also a crucial development, which addressed the issue of the high cost of deploying a constellation of 24 satellites in medium-Earth orbit. We now see that the successful launch and deployment of NTS-2 in 1977 marked the beginning of GPS as a practical and operational system.
The several histories and accounts of the invention of GPS all agree that its inventors faced obstacles in funding and designing the system. They do not agree on whether the Air Force or the Navy deserves primary credit for its invention. One reason for the dispute between the Air Force and the Navy was how the services had a different perception of the use of GPS. The Navy was concerned with positioning, and by extension, navigation over the open oceans. Parkinson, in his recollection of his role at the Joint Program Office, stressed the use of GPS for targeting. Navigators had a variety of other methods of finding their position, although GPS would be superior to them all. The Air Force, by contrast, was struggling with the difficulties of targeting bombs, as evidenced by the experiences in Vietnam. During and after World War II, the American public was told of the miraculous performance of the Norden Bombsight, with its ability to hit a “pickle in a barrel.” The reality was that the Norden was not very effective. Radar-targeted bombs were used successfully in the 1991 Persian Gulf War, but they, too, had limitations. The ability to deliver weapons to precise targets, whether by piloted aircraft or by drones, is one of GPS’s most dramatic and controversial impacts on military affairs.
Rather than address the question of who invented GPS, we provide the following alphabetical listing of US government agencies, departments, branches of military service, and federally funded laboratories, noting the contributions each has made to the current Global Positioning System as it is deployed today. (We omit private corporations, including Rockwell, Magnavox, Trimble, or Garmin, which also played a role in bringing GPS to its present state.)
US Government Contributors to the GPS as It Is Used Today
Aerospace Corporation: concept of satellite guidance for intercontinental ballistic missiles
Air Force, Cape Canaveral and Vandenberg Air Force Bases: launch vehicles, launch facilities
Air Force, Pentagon Headquarters: leadership of Joint Program Office
Air Force, Schriever Air Force Base: GPS ground control facilities
Army: specifications for portable receivers
Coast Guard: differential GPS
Defense Mapping Agency: accurate maps
Department of Energy: nuclear detection devices on GPS satellites
Federal Aviation Agency: Wide Area Augmentation Service
Jet Propulsion Laboratory: pseudo-random number coding used for ranging; Phase-Locked Loops
National Bureau of Standards, later National Institute of Standards and Technology: development of atomic clocks and frequency standards
NASA Ames Research Center (also the Research Institute for Advanced Studies in Baltimore, Maryland): Kalman filter
National Geospatial-Intelligence Agency: ongoing determination of the geoid
Naval Research Laboratory: basic architecture of GPS; prototype Timation and NTS satellites; design of launch trajectories and orbits
Naval Observatory: master clock
Naval Surface Warfare Center, Dahlgren, Virginia: determination of the geoid, orbit determination
The list may be incomplete, and it does not include work done on terrestrial predecessors of GPS, including LORAN, Omega, and various aircraft navigation technologies. If one looks at the origins of other modern technologies, including the digital computer, the Internet, or microelectronics, one could construct a similar list. What can we conclude from this example of GPS? A few points stand out.
First, the US government, and especially the US military, in spite of all the bad press it gets about waste and mismanagement, is capable of remarkable technological innovation. It is also capable of sustaining an effort over the long period of time required for a new technology to mature. We have noted the times when GPS funding and support were in jeopardy, but it survived. Few private entities have demonstrated such an ability. The decision to install atomic clocks onboard spacecraft orbiting at medium-Earth orbit, at a time when fragile and bulky atomic clocks were just emerging from the laboratory, was a bold and genuine innovation that, like most such breakthroughs, only seems obvious in hindsight.
Second, the Global Positioning System is truly an “invisible infrastructure”: one whose day-to-day operation is crucial to life around the world, and one that deserves, even demands, a high degree of financial support and human resources for its continued operations and enhancement. At the same time, the ever-increasing costs of the American system do not bode well for its future.
Third, the system will continue to serve both military and civilian users in ways that were anticipated when GPS was first deployed, but that have since evolved in unanticipated ways. That trend, with all its uncertainty, will continue.
Finally, a remarkable set of technical innovations—the Internet, microprocessor, cellular telephony, and GPS—were incubated in the early 1970s, as the American public was shocked by the suspension of cheap oil imports. Forty years later, the United States is facing many similar challenges, especially regarding health care, civil infrastructure, and energy. The history of the Global Positioning System suggests solutions to current issues facing the United States may be under development, out of public view. Those in government and the private sector who are addressing these issues would do well to study that 40-year trajectory, with all its complexity.
