GPS Declassified

by Richard D. Easton

  The O’Grady search-and-rescue effort, reminiscent of incidents in Vietnam thirty years before, prompted calls for immediately funding a stalled Air Force program to replace the outdated PRC-112 with a digital radio capable of satellite communications.9 By fall 1995, Motorola was working under a “quick-reaction program ” to add GPS to the PRC-112, creating a model known as the Hook 112, but those units still relied solely on less powerful “line-of-sight ” communications.10 In February 1996 the GPS joint program office awarded Rockwell International a $13 million contract to build eleven thousand Combat Survivor Evader Locator (CSEL) radios for delivery by 1998.11 Contract options provided for twenty-seven thousand radios by 2001 at a cost of $67.2 million.12 CSEL development took longer than expected, and in 1999 Department of Defense officials deemed the first radios “not operationally suitable. ”13 Refinements continued. In 2004 the military began fielding the CSEL radios, first proposed in 1991, at a cost of about $5,000 apiece.14 By 2011, Boeing (which acquired Rockwell International’s aerospace and defense businesses not long after the initial CSEL contract was awarded) delivered fifty thousand radios for use by the Army, Navy, and Air Force.15 Wars in Afghanistan and Iraq with hundreds of thousands of troops and many civilian contractors on the ground enlarged the radio’s mission well beyond locating downed pilots to include general “personnel recovery. ”16 CSEL radios, sometimes called the military’s “global 911 ,” combine a precision-code GPS system, a locator beacon, over-the-horizon satellite data communications, and line-of-sight voice communications.17 The GPS coordinates and secure digital signal allow search-and-rescue teams to locate and authenticate missing personnel even if they cannot make voice contact, prompting CSEL program managers to coin the slogan “no search and all rescue. ”18

  The military’s search-and-rescue needs, illustrated by the O’Grady episode, provided the impetus to combine compact mobile communications with precision GPS tracking of receivers. Public safety concerns and commercial motives later drove a similar evolution in civilian telephony. In the same way that development of increasingly accurate atomic clocks had made precise satellite navigation feasible decades before, technological advances paved the way for GPS to become a ubiquitous public utility. One was the evolution of techniques to augment the accuracy of GPS signals, providing more precise and diverse applications; another was miniaturization of GPS receivers onto a single computer chip, enabling their migration to and integration with other devices. However, technological progress by itself was not enough. The private sector faced uncertainty.

  Growing Public Policy Issues

  In early June 1995, while Scott O’Grady was evading capture and using GPS to aid his rescue, Congress and the Department of Defense had just received a report from a yearlong study concerning the future of the technology, jointly prepared by the National Association of Public Administration (NAPA) and the National Research Council (NRC).19 Simultaneously, the White House Office of Science and Technology Policy and the National Science and Technology Council were awaiting delivery of a similar study undertaken by RAND.20 Leaders commissioned these studies to plot the direction of GPS policy, recognizing it had not kept pace with technology.

  As commercial interest in GPS surged following the Persian Gulf War, policy makers realized that the system’s dual-use nature posed fundamental challenges for balancing national security needs with the enormous economic opportunities it offered. Ongoing U.S. military control of GPS was a source of tension for civilian users, both domestic and abroad. Some thought the government should privatize it partially or completely. Others envisioned oversight by a multinational civilian agency akin to the International Civil Aviation Organization (ICAO).21 Solving these issues was difficult because they crossed not only borders but also traditional bureaucratic boundaries, and there was no mechanism for sharing information and responsibilities across the different missions of the Departments of Defense, Commerce, and Transportation, a problem often described as “stove-piping. ”22

  One lesson the Gulf War taught about satellite systems was that “everyone will want them ,” Martin C. Faga, an assistant secretary of the Air Force, told a U.S. Space Foundation symposium in April 1991.23 Already the Soviet Union had launched much of its similar GLONASS constellation (now a Russian system, following the Soviet breakup in December 1991). The European Union (EU), dependent on two defense-run systems, began to contemplate building its own system. Before the end of the decade, in May 1999, the EU authorized the first funds for its commercially oriented Galileo system, described initially as a twenty-one-satellite constellation similar to GPS.24 Therefore, concerns in the early 1990s about how the United States should manage cooperation and competition with other global navigation satellite systems were quite valid.

  From an economic standpoint, many feared that the policy of degrading the civilian signal and the military’s ability to shut down GPS service at its discretion would suppress private investments in research, development, and manufacture of commercial products or consumers’ willingness to buy and integrate those products into their business or personal activities. Domestic commercial GPS sales were $213 million in 1991, and the U.S. GPS Industry Council projected a 62 percent rise by 1996.25 Farmers had already begun experimenting with GPS to spread expensive fertilizers more accurately, boosting yields while reducing costs.26 The Department of Transportation estimated that traffic congestion caused $73 billion in lost productivity each year, highlighting the early opportunities that many companies saw in the automobile navigation market.27 From tracking endangered species to fleets of rental cars and delivery trucks, GPS empowered a surge in geographic information systems (GIS), a $1.41 billion worldwide market in 1990 that the market research firm Data-quest projected would double by 1994.28 Some companies with large communications infrastructures were already adopting GPS timing to synchronize their data networks, but Atlanta-based Southern Company, a power and electric utility operator, specifically cited the military’s ability to degrade the signal when it chose in 1991 not to use GPS to time its networks in five states.29 Private investors also had to contemplate whether the government would reliably maintain the system over the long term and whether service would remain free of charge or be subject to taxes or user fees.

  From the military’s perspective, national security concerns trumped potential domestic or worldwide economic benefits. Following the successful debut of GPS in the Persian Gulf War, U.S. military leaders feared that enemies would soon take advantage of the signals for hostile use. GPS capability offered Third World adversaries an inexpensive way to upgrade SCUD missiles or even to launch what the Pentagon termed “the poor man’s cruise missile ” against the United States or U.S. interests abroad.30 The strategy to counter this threat was to carefully limit access to the more accurate, encrypted, and jam-resistant military signal (the Precise Positioning Service, or PPS) and to “dither ” the civilian signal (the Standard Positioning Service, or SPS), rendering it less accurate. In late August 1991, a few months after the Air Force reactivated Selective Availability following the war, the U.S. government revised its international trade regulations to reflect the dichotomy, classifying civilian receivers as unrestricted “general destination items ” but maintaining tight export restrictions on military-grade receivers, treating them as “munitions. ”31 By December 1993, the Department of Defense reported that about eleven thousand military-grade GPS devices had been sold or provided to allies, with nearly nine thousand going to Europe and hundreds each to Japan, Israel, Canada, South Korea, and Australia.32

  Even as the military degraded the civilian signal, Pentagon officials acknowledged “an inherent quandary ” posed by simultaneous multimillion-dollar programs the Coast Guard and Federal Aviation Administration pursued to boost SPS accuracy for enhanced safety around seaports and airports.33 These local augmentation systems used the technique known as differential GPS (DGPS), which employs GPS receivers and ground-based radio beacons at fixed locations with precisely surve
yed latitude, longitude, and elevation coordinates. The reference stations make it possible for computers to detect tiny inaccuracies in the signals from space, calculate the differences, and transmit corrections to users via the ground beacons. At that time Selective Availability reduced the civilian signal’s accuracy to within about 328 feet (100 meters), and the precise military signal was accurate to within about 38 feet, but DGPS could provide accuracies within about 10 feet.34 While the military could presumably shut down DGPS systems serving U.S. territory in the event of an attack, it resisted plans backed by the FAA and the International Air Transport Association to build a Wide Area Augmentation System (WAAS) that would use multiple reference stations and separate non-GPS communications satellites to broadcast corrected signals to airplanes across the entire continent.35

  As the Pentagon and Department of Transportation tried to resolve their differences, U.S. officials repeatedly sought to reassure the private sector, particularly the huge civil aviation market. The FAA administrator, in a letter to the ICAO’S Tenth Air Navigation Conference in September 1991, pledged to make the Standard Positioning Service available to the international community at no charge for at least ten years (starting in 1993).36 Other than specifying a time frame, this was essentially the same offer President Reagan had made a decade before. The FAA repeated that pledge at ICAO assemblies in 1992 and 1994, assuring provision of SPS for the “foreseeable future ,” subject to available funds, and additionally promising to provide at least six years of advance notice before terminating GPS or eliminating SPS.37

  All of this activity occurred before GPS was officially complete. Not until June 1993, almost twenty years after the Defense Systems Acquisition Review Council authorized the program, was the full constellation of twenty-four satellites orbiting the earth. Following several months of testing, Secretary of Defense Les Aspin declared Initial Operational Capability (IOC) in a December 8 letter to the Department of Transportation. After nearly a year and a half of further testing, the Air Force declared Full Operational Capability (FOC) in April 1995.38 These actions were not mere ribbon-cutting-style announcements; they were formal certifications that the system met specific criteria for accuracy and reliability—for example, accurate horizontal positioning within one hundred meters 95 percent of the time. The FOC declaration assured authorized users of the Precise Positioning Service that PPS met its more-stringent requirements, which was of significance to U.S. military forces and allies. The IOC certified that SPS met standards set forth in the Federal Radionavigation Plan, a technical planning and policy document prepared jointly by the Defense and Transportation Departments every two years. One practical effect was to designate GPS receivers as satisfying federal maritime regulations requiring ship-borne electronic position fixing devices.39 Such devices enable vessels to report their position manually or automatically to avoid accidents, such as in fog. In March 1999 the Coast Guard activated an augmentation system called the Maritime Differential GPS Service. It consisted of a control center and network of radio beacons for enhanced navigational accuracy along the coastlines of the continental United States, the Great Lakes, Puerto Rico, the U.S. Virgin Islands, portions of Alaska and Hawaii, and much of the Mississippi River basin.40

  Approving GPS for Aviation

  The FAA began phasing in GPS use in June 1993, six months before the IOC declaration.41 Pilots could immediately use approved GPS equipment as their primary en route navigation method for domestic and oceanic routes, but its use with landings came with restrictions. At first pilots could use GPS only for nonprecision approaches—instrument landings that use ground-based radio signals to align the plane with the runway but do not provide vertical guidance, which remains visual. By contrast, landings with reduced visibility require precision approaches, where ground equipment transmits both lateral and vertical guidance. Airports use a variety of navigation aids, and some lack instrument landing systems that can provide vertical guidance. The initial FAA phase-in opened five thousand GPS approaches at 2,500 U.S. airports.42

  Formal FAA approval of GPS for civil aviation followed on February 17, 1994, and the next month the agency published the first certified GPS approaches—a process that would take years to cover all affected airports.43 Published approaches originally filled thick paper manuals, but with the advent of digital circuitry they were programmed into cockpit instruments, including GPS receivers. Until the FAA certified a particular runaway approach for GPS, pilots had to follow the traditional approach and actively monitor existing ground-based navigation aids unless the plane was equipped with GPS instruments featuring Receiver Autonomous Integrity Monitoring (RAIM) or an equivalent method of detecting faulty satellite signals.44 RAIM circuitry and software enables receivers to verify the accuracy of a position derived from four satellites by comparing it to signals from a fifth or sixth additional satellite.45 Despite the requirement for backup systems, FAA officials left no doubt that GPS was the direction for the future. At the time, FAA administrator David Hinson remarked that he saw no reason GPS would not become the only navigation system.46

  Hinson’s comment reflected a widely held view: the arrival of GPS represented enormous potential cost savings for the general aviation sector, airlines, airports, and the overburdened FAA-managed air traffic control system. Some seven hundred thousand general aviation pilots operating two hundred thousand aircraft looked forward to the greater affordability of panel-mounted GPS receivers costing $2,000 to $5,000 that would eventually replace $20,000 worth of traditional navigation equipment.47 Continental Airlines in 1993 was the first carrier to seek FAA approval for GPS-only approaches into Aspen and Steamboat Springs, Colorado, where weather conditions often forced cancelation of a quarter of the airline’s scheduled flights or diversions to alternate airports.48 The airline calculated that its investment in Honeywell flight management systems with RAIM-enabled GPS equipment for its regional jets would achieve payback in less than one year.49 For Honeywell, it was the first sale of the system to a regional carrier—a large potential market; for the FAA, the early success fueled hopes that the new technology could help contain the rising costs of extensive ground-based instrument landing systems and even extend precision approaches to airports that lacked them.50 The total number of airports and landing areas of all types in the nation grew by 15 percent from 1980 to 1990, when there were 17,490 facilities.51 By 1994, there were 853 more.52 From the time Congress deregulated the airline industry in 1978, the number of passengers boarding aircraft rose 270 percent to about 465 million in 1990.53 That figure surpassed 528 million by 1994, driven by fare wars that erupted in 1992.54 As major carriers abandoned smaller cities in favor of the hub-and-spoke system, smaller regional carriers moved in. These commuter airlines strained the FAA’S inspection regime, accidents among them spiked, and the GAO issued a report that prompted the FAA to hire more inspectors and refocus its attention on regional carriers.55 Despite increased volume, airline travel became a commodity with razor-thin or zero profits, forcing carriers to cut costs and achieve greater efficiencies wherever possible.56

  A Continental executive, testifying before the House Subcommittee on Technology, Environment, and Aviation in March 1994, estimated that GPS navigation would allow his company to capture $1.9 million annually in revenue otherwise lost due to weather-related flight cancellations.57 Beyond fewer cancellations, he said, GPS navigation could save the airline industry $5 billion annually through reduced delays and more direct routing.58 With that figure in mind, and citing projected industry-wide spending of $500 million to $740 million on new GPS-enabled avionics, he urged the government to speed development of the FAA’S proposed Wide Area Augmentation System.59 FAA associate administrator Martin Pozesky told the same subcommittee that his agency planned within months to authorize privately owned local-area DGPS systems at airports to provide precision approaches under Category I weather conditions.60 Category I instrument landings require a pilot to be able to see the runway well enough to decide whet
her to land at a range of at least 1,800 feet and a height no lower than 200 feet above the runway.61 Category II and III approaches, denoting poor visibility, require much more precise instrument guidance, as they place the pilot closer and lower before he spots the runway, leaving little margin for decision making. Pozesky told the subcommittee that WAAS could provide Category I landing guidance at virtually all major airports across the United States without the need to install local ground-based DGPS systems.62 At the time officials estimated that about one hundred existing approaches would need differential ground systems for more precise Category II and III landings.63 The decision to back WAAS also signaled a move away from microwave landing systems, a competing technology that many European nations continued to pursue.64

  By mid-1994, the FAA began soliciting bids for WAAS, anticipating that it could begin fielding the system in mid- to late 1997 and complete it within six years for between $400 and $500 million.65 The design called for about two dozen ground reference stations across the nation and a central station for sending the signals via satellites to airplanes. Five teams, each a consortium of companies, bid on the project, but when the time came to award the contract early in 1995, the announcement was delayed; the FAA had learned the Pentagon was planning new experiments to jam the same signal it was trying to enhance. After months of wrangling, the Transportation and Defense Departments announced they would conduct “joint testing and review of WAAS ,” but with the civil aviation industry unnerved by the episode, this time President Bill Clinton himself sent a letter to the ICAO reaffirming the U.S. commitment to civil use of GPS.66