GPS Declassified

by Richard D. Easton

  Fig. 7.2. AGM-84 standoff land attack missile. The Navy’s first GPS-guided missile, the AGM-84 was a modified Harpoon antiship missile, later also deployed from aircraft. (U.S. Navy photograph)

  Strikes Yield Cautious Assessments

  Four hits in seven tries is not a horrible ratio for a weapon rushed into service, but too few missiles were launched to draw statistically meaningful conclusions. That was apparently also true of the CALCMs. The thirty-five missiles the Air Force fired were later reported to have achieved 85–91 percent of the mission’s objectives, with only two going astray, as many as thirty-one hitting their targets squarely, and one slicing its aim point—a telephone pole—in half. Hard numbers with official endorsement are elusive.18 Queried by reporters about the missile’s accuracy when the weapon was revealed during a press briefing, Pentagon spokesman Pete Williams said, “The Air Force considers it to have been very effective. But the experts who analyzed this don’t believe that it is absolutely possible to pinpoint the precise success rate. ”19 The Pentagon’s Conduct of the Persian Gulf War: Final Report to Congress, delivered in 1992, states that the CALCM (which at the time was still called an ALCM) “played an important role in Operation Desert Storm. ” It provides no statistics but instead offers this cautious appraisal: “A complete assessment of the AGM-86C’s effectiveness is difficult to determine because of incomplete battle damage assessment (BDA) and the inability to distinguish damage caused by other munitions that struck some of the same targets. All missiles launched successfully transitioned to cruise flight. Demonstrated accuracy appears consistent with the results obtained from testing. ”20

  In other words, to ensure success the military intentionally struck many targets repeatedly using a variety of bombs. The use of new GPS-guided missiles that were untested in battle would certainly have warranted such a strategy. A major review, the Gulf War Air Power Survey, released in 1993 by an independent, Air Force–appointed panel, was similarly cautious: “The CALCM’s high explosive fragmentation warhead is designed to attack soft targets. Nevertheless, CALCM was apparently effective in Desert Storm against electrical generator switching facilities and exposed communications relay facilities. In contrast to TLAM [Tomahawk land attack missile], generalizations concerning CALCM effectiveness in Desert Storm must be treated with caution in light of the small number fired. ”21

  In any case, the thirty-five CALCMs were sufficient to impress the Air Force to order hundreds more, and today the missiles feature upgraded avionics with multichannel GPS receivers and three-thousand-pound bombs.22

  The TLAM referenced in the survey is a TERCOM-guided, deep-strike weapon the Navy launched from ships and submarines against heavily defended Iraqi targets as far as seven hundred miles away. (It now has a listed maximum range of one thousand miles and uses GPS.)23 The Navy fired 288 TLAMs during the Persian Gulf War—116 during the first twenty-four hours and nearly two-thirds of the total within the first forty-eight hours of the six-week air campaign.24 All but six achieved cruise flight. Footage of these twenty-foot-long missiles riding fiery plumes from the decks of destroyers, sometimes against a pitch-black sky or breaking the surface after a submarine launch, were among the most vivid images televised during the war. They form a sort of visual bookend with grainy, black-and-white videos of laser-guided missiles (different weapons, not TLAMs) perfectly aligned in the crosshairs diving into airshafts on rooftops. These images provided a televised, round-the-clock public introduction to precision-guided weapons, or “smart bombs ,” which had been under development since the Vietnam War. However, war coverage did not produce an equal public introduction to GPS for a variety of reasons— the Air Force CALCMs remained secret, the Navy used so few SLAMs, receivers were in short supply, the ground war was brief, and the complex system was not easily explained.

  Call It What You Will

  As the military pressed GPS technology into service ahead of schedule for the war, the news media faced the challenge of introducing unfamiliar terminology to an audience of millions. The approaches varied and the results were uneven. Prior to Desert Storm, detailed reporting about GPS remained mostly the province of professional journals like Aviation Week & Space Technology, the Journal of Surveying Engineering, Mining Magazine, or Offshore (aimed at the oil and gas industry). GPS World, a monthly publication devoted to the technology, started in January 1990. Business-oriented publications such as the Wall Street Journal and Forbes magazine wrote about GPS from its formative years primarily because the defense contractors building the system were important to investors. Stories for more general audiences were sporadic. An early example appeared in the sports section of the Palm Beach Post on November 5, 1989, following the Palm Beach International Boat Show. “Global Positioning System Will Be Rave of the Future ” read the headline. In the story vendors and boating enthusiasts commented on the buzz created at the show by GPS receivers, including Magellan Corporation’s new handheld model, which cost $2,995, and Trimble Navigation’s $9,000 marine unit. The article included a good explanation of how GPS works.

  As the troop buildup in Saudi Arabia progressed during the fall of 1990, the CBS Evening News aired a segment with Scott Pelley interviewing Marines. He referenced a network of satellites beaming navigation instructions to troops in the desert and identified it, saying, “The network is called the global positioning system. ”25 However, the focus was not on the system’s capabilities but rather on the shortage of receivers. Four days before the air campaign began ABC Weekend News Sunday concluded its broadcast with a report from the Winter Consumer Electronics Show in Las Vegas, where Pioneer introduced its Avic One satellite navigator for automobiles.26 Reporter Tom Schell explained that it used the “global positioning satellite network ” to update the car’s location to within forty feet. The program did not mention the satellite system’s military significance or connection to the impending war.

  After the shooting started most war coverage lacked the time and space to provide many details about GPS. In much the same way that reporters in the 1950s introduced satellites to a general audience by calling them artificial moons, reporters covering Desert Storm often commingled GPS with reconnaissance, communications, and weather satellites. For example, on the February 8, 1991, CBS Evening News, Bruce Hall reported on the role of spy satellites and noted that the military had “a group of satellites ” that could tell ground troops their location on the featureless desert. An unidentified soldier he interviewed remarked simply that the system worked great.27 Some reports artfully depicted the system’s utility. In a February 25, 1991, Los Angeles Times article, “Ground War Puts Some Exotic New Weapons Systems to Test ,” staff writers Karen Tumulty and Bob Drogin described the unnamed system as “a two-pound, high-tech compass that gets its readings from satellites rather than magnetic poles. ”28 A more in-depth wartime look at GPS was a February 6, 1991, special to the New York Times business section, titled “Business Technology: War Spurs Navigation by Satellite. ”29 Andrew Pollack’s story fully explained the technology, its military and emerging civilian uses, and the rise of receiver manufacturers Trimble Navigation and Magellan Systems. Some war coverage billed as an examination of high-tech military systems overlooked GPS altogether. CNN’s Crossfire devoted the entire program on January 25, 1991, to the issue of whether opponents of Reagan’s military buildup owed an apology given the success of American high-tech weapons. GPS was not mentioned in a discussion that included aircraft carriers, stealth fighters, cruise missiles, smart bombs, Patriot antiballistic missiles, the M-1 tank, and the Bradley fighting vehicle.30 A CBS News special report about fighting a high-tech ground war, which aired February 23, 1991, mentioned multiple-launch rocket systems, the night vision and laser-targeting capabilities of the Apache helicopter, and the speed and accuracy of the M-1 tank, but not GPS.31

  The war’s end brought countless media analyses and spawned many books. Turner Broadcasting, CNN’s parent company at the time, rushed a book to market in the summer of 19
91. It of course mentions nothing about the classified CALCM attack. Numerous references to “smart bombs ” explain bombs and missiles guided by lasers, TV cameras, or infrared “heat-seeking ” systems. Its index lacks the terms NAVSTAR, Global Positioning System, or GPS, and none of the three appear explicitly in the book, although a few passages come close to mentioning them. One illustration describing the SLAM states, “While the missile is in flight, the satellite receiver/processor updates the missile’s inertial navigation system ” (emphasis added).32 In another instance the text states, “Also overflying the Middle East were U.S. global-positioning, meteorological, and launch-warning satellites. Positioning satellites permitted U.S. troops on the ground to use hand-held receiving devices to determine their exact position without reference to any ground features. ”33 These wording choices suggest careful editorial decisions recognizing the public’s lack of familiarity with GPS. Two years later, a comprehensive and popular account of the war, Crusade: The Untold Story of the Persian Gulf War, by the Pulitzer Prize–winning journalist Rick Atkinson, avoided the terms NAVSTAR, Global Positioning System, or GPS. Its account of the by-then declassified CALCM mission discusses the arms control issues posed by replacing the nuclear warheads but omits any mention of GPS guidance.34

  Despite its complexity and the varied ways newspapers, television, and books explained or worked around it, GPS emerged from the war with much broader name recognition. One other medium deserves mention—word of mouth. More than 540,000 coalition troops from thirty-one countries discovered a new battlefield dynamic as their units navigated aircraft to precise weapons launch points or crossed vast expanses of featureless terrain in vehicles or on foot. These troops witnessed the utility of GPS and returned home after the war to talk about their experiences. Many were probably the earliest adopters of GPS navigation devices over the following decade.

  Consider this passage from the Gulf War Air Power Survey, describing how GPS improved the delivery of conventional weapons: “Although laser-guided munitions constituted only 6.7 percent of bombs dropped from tactical aircraft during Desert Storm, accurate bombing played a pivotal role in the exercise of air power by Coalition and particularly U.S. air forces. The relatively low percentage of precision-guided bombs reflects in part the fact that many of the unguided bombs were dropped from ‘smart’ platforms (e.g., aircraft) that were, at least in principle, capable of achieving near precision-guided munitions accuracy with ‘dumb’ bombs. ”35

  Despite media fascination with “smart ” bombs, roughly 210,000 bombs used during Desert Storm were unguided.36 The U.S. military had installed GPS equipment in only about 300 aircraft before the war and sent some to the theater outfitted with portable receivers.37 About half of the 66 B-52 bombers, less than a third of the roughly 250 F-16 fighters, and a handful of the 82 F-111 fighters were GPS-equipped.38 Commercial receivers were the only option for coalition aircraft, so British pilots attached handheld GPS units with Velcro to the instrument panels of their Jaguar fighter-bombers.39 Pilots also had to ensure that their GPS receivers and inertial navigation systems used the same map coordinate standards, or bombing errors resulted.40 Whether the GPS was permanently installed or improvised, GPS-equipped planes constituted a tiny fraction of some 1,600 attack aircraft used by U.S. and coalition forces, but they led others in their formations to precise launch coordinates, which in some cases reportedly doubled bombing accuracy.41

  GPS capability influenced planning for the first strikes of the air campaign—raids to destroy two Iraqi early warning radar sites near the western border, opening a window for squadrons of strike fighters headed deep into Iraq. Planners lacked detailed maps of the target locations, and they wanted eyewitness confirmations that the attacks had achieved complete destruction—something long-distance missile strikes alone would not provide.42 Four Air Force Special Operations Pave Low helicopters equipped with GPS led eight Army Apache attack helicopters on terrain-hugging, under-the-radar flights across the desert. Since the tightly drawn mission plan required hitting two sites forty miles apart within twenty seconds of each other, the task force leader used the time from a GPS satellite’s atomic clock to call out the synchronization mark for all cockpit clocks as the mission began.43 The Pave Lows dropped chemical glow sticks on the ground about ten miles from each site, marking precise points where they broke off their lead and the Apaches inputted predetermined targeting coordinates for their Hellfire missiles.44 The Apache crews followed up the Hellfire strikes by hitting the sites with one hundred smaller, unguided rockets and four thousand rounds of cannon fire to finish the job before darting back toward the border as coalition jets screamed overhead toward Baghdad.45

  GPS improved the military’s ability to locate and retrieve troops and equipment caught behind enemy lines. At the start of the ground campaign, an eight-man Army Special Forces team was inserted deep into Iraq, about two hundred miles south of Baghdad, to monitor military traffic on a highway. Discovered by civilians and later engaged by more than 150 Iraqi soldiers, the team requested air cover and an “emergency exfiltration ,” which arrived in time to save everyone thanks to having precise coordinates of their location.46 In a similar incident that same day a Navy Seal team was being picked up after completing a mission off the coast of Kuwait when they accidentally dropped an expensive piece of equipment into the water. Stopping to retrieve it risked detection and compromising the mission, so they recorded the precise location using GPS coordinates and returned the following night to recover it.47

  Navy vessels used GPS not only to navigate to specific launch points as required for the TLAM’s terrain-matching system but also to accurately map and clear extensive minefields. Saddam Hussein, believing that air power was not decisive in wars and assuming that coalition troops would find maneuvering in the desert as difficult as his own forces did, expected an amphibious invasion. A large full-color relief map discovered after the war in a Kuwaiti building the Iraqis converted to a military post confirmed that Hussein had committed seventy thousand to eighty thousand troops and up to half of his artillery to defend the Kuwaiti coast.48 Iraq turned oceanfront high-rise condominiums into gun perches, littered the beaches with earthen berms, trenches, mines, barbed wire, and other obstacles, and placed more than 1,200 sea mines in a 150-mile arc from the Iraqi-Kuwaiti border southward to the Saudi Arabian border.49 Navy and coalition ships conducted minesweeping operations prior to the ground offensive as part of a “right feint ” maneuver designed to convince Hussein he was right and spent a year after the cease-fire destroying mines and removing war wreckage to reopen commercial shipping lanes.

  Space Facilitates Ground Offensive

  The right feint’s counterpart, the western “left hook ” flank attack, which Gen. H. Norman Schwarzkopf, commander in chief of the U.S. Central Command, compared to a Hail Mary play in football, vividly illustrates the impact of GPS during Desert Storm. Soon after knocking out Iraq’s electronic communications and grounding its air force planes or sending them fleeing to Iran, Schwarzkopf ordered more than two hundred thousand troops and tens of thousands of vehicles massed on the Saudi-Kuwaiti border to move, undetected, more than two hundred miles to the west. The westward shift positioned two full U.S. Army Corps, the XVIII Airborne Corps and the VII Corps, pulled from Cold War bases in Germany, to bypass and encircle the bulk of Iraq’s dug-in positions. This enormous march of men and materiel spanning three weeks did not itself require GPS navigation. The entire convoy rolled northwest on a narrow but straight two-lane blacktop road adjacent to the Trans-Arabian Pipeline. Once the troops, armored equipment, and logistical supply units left the roadway and prepared for desert battle, however, GPS navigation, together with satellite communications and imagery and night-vision devices, became indispensable. Never before had armies waged battle on such a large scale, both day and night in hostile desert conditions.50 GPS helped advancing units maintain alignment with others on each flank, helped avoid fratricide through mistaken engagement with frien
dly forces, aided combat search and rescue, and helped ensure the delivery of food, fuel, and supplies where needed on a timely basis.51

  This new situational awareness of the location of friendly troops marked the birth of what became Blue Force Tracking (blue for friendly forces, red for enemies). After the war, work began on systems like the Force XXI Battle Command Brigade and Below (FBCB2) program. Combining GPS, a satellite phone, a laptop computer, and special software, the technology displays maps with blue icons pinpointing friendly units and updates their positions automatically in real time. Users can communicate by radio, text message, or e-mail. Blue Force Tracking expanded rapidly in 2003 during Operation Iraqi Freedom and has evolved into subsequent generations known as Joint Capabilities Release and Capabilities Set 13, with more than one hundred thousand devices installed in U.S. armored vehicles, tanks, and helicopters.52 Although Schwarzkopf does not use the term Global Positioning System in his autobiography, It Doesn’t Take a Hero, published a year after the war, he mentions the technology in a reference to the challenges of desert warfare. He writes, “In Europe, soldiers had been able to orient themselves in relation to roads, towns, forests, and other landmarks; in the desert, there were no landmarks and even the dunes moved. So we had to quickly teach the use of satellite navigation equipment, celestial navigation and dead reckoning ” (emphasis added).53

  Celestial navigation, of course, requires clear weather, but the Persian Gulf War occurred during the worst conditions recorded in the fourteen years the Air Force had been keeping records of Iraqi weather.54 Bad weather forced cancellation of 15 percent of planned air sorties during the first ten days of the air campaign and affected operations throughout the war.55 The ground campaign began February 24 amid rain and sandstorms and after a tug-of-war between the generals in the field, who wanted to wait for better weather, and civilian leaders in Washington, who were managing last-minute negotiations with the Soviet Union that could have resulted in Saddam Hussein giving up Kuwait but keeping his massive military apparatus. Absent GPS, the outcome of the war may not have been different, but its duration would certainly have been longer.