The authors of a popular Schwarzkopf biography, In the Eye of the Storm: The Life of General H. Norman Schwarzkopf, published in late summer 1991, describe vividly the battlefield advantages of GPS. Their use of the plural systems also highlights the still-evolving use of the term at the time, as well as the trend toward conflating the receivers with the entire system:
This element of surprise was compounded on the second day of the war by an appalling sandstorm that reduced visibility to less than a hundred feet. The storm created problems for the coalition. For example, some aerial resupply missions had to be stopped. But it created far more problems for the disoriented Iraqis. Once again, superior technology aided Schwarzkopf’s forces. Using the navigation devices called global positioning systems, they always knew exactly where they were and where they were heading. These high-tech gadgets, based on digital coordinates of positions and satellite connections, could tell soldiers how far they were from pre-set targets even as sand blew sideways into their faces. Rampaging out of whipping sand on Iraqis looking in the other direction, or, later, out of the sight of soldiers who did not even know the coalition was inside Iraq, the allied forces had an effect that was indeed as sudden, dramatic, and enveloping as thunder and lightning.56
Improvisation Saves the Day
Before troops could employ GPS in the conflict, the military had to overcome several problems. Foremost was the shortage of receivers and accurate maps. Because the system would not be complete until 1993, the services had not yet acquired many receivers, much less trained personnel widely in their use. The Army owned just five hundred demonstration receivers when troops began deploying to Saudi Arabia for Operation Desert Shield.57 Despite general unfamiliarity with GPS, its impact was immediate and troops quickly embraced the new technology, as illustrated by the response of an assistant signal officer from the 11th Air Defense Brigade when asked about GPS receivers: “If you mean those green position locators, they are lifesavers. Whenever we sent someone to another unit for coordination, we entered that unit’s ten-digit coordinates and the SLGR (small, lightweight GPS receiver) directs them to the command post. Before, we had people getting lost in the desert, but since we got the three GPS receivers, nobody has got lost. ”58
The SLGR, or “Slugger ,” a version of Trimble’s Trimpack receiver discussed in the preceding chapter, was the most widely fielded receiver in the Persian Gulf War, with about four thousand ultimately deployed.59 Although it lacked the ability to decode the more precise, encrypted (P code) signals used by the military’s AN/PSN-8 “Manpack ” GPS receiver built by Rockwell Collins, it was more versatile. The Manpack, about the size of two stacked shoeboxes, weighed seventeen pounds and was portable in the sense that a soldier could wear one on a special backpack-style frame. In practice, it more often was lashed to a wheeled vehicle or helicopter.60 The SLGR weighed three and a third pounds and was about two inches thick by seven inches square—small enough and light enough to hold in one hand. With the switch of a button it could display coordinates in several different mapping grid systems, making it usable for aviation, ground movements, and artillery support.61 The difference in cost between the SLGR and Manpack exceeded their size and weight differences. A SLGR cost about $3,400, whereas the Manpacks cost $45,000 apiece.62 The Magellan NAV 1000, smaller still and battery-powered, was the second most popular receiver, with about one thousand used in the Persian Gulf War.63 Commercial receivers provided accuracy to within about eighty-two feet in each direction (latitude, longitude, and altitude) compared to the fifty-three-foot accuracy of military receivers.64 The military later developed a receiver known as the PLGR (precision lightweight GPS receiver), which decoded the encrypted signal and was resistant to jamming (radio interference that blocks the GPS signals) or spoofing (false signals broadcast to cause receivers to generate incorrect coordinates).
Soon after the first troops arrived in Saudi Arabia, the Pentagon began placing orders for commercial receivers and eventually ordered about ten thousand. Some service members asked their families to ship them commercial units. The demand strained production capacity, and by the war’s end, the number deployed by all branches of the military totaled 4,490 commercial and 842 military receivers, with the Army absorbing about four-fifths of the commercial versions and two-thirds of the military ones.65 Coalition partners began the conflict with about two dozen receivers and eventually fielded more than two thousand of the devices, which Arab ground commanders dubbed “the magic compass. ”66 As with aircraft, U.S. ground commanders apportioned available receivers where they thought they could do the most good. This meant, for example, divvying up three thousand receivers among forty thousand vehicles in the VII Corps alone. Receivers typically went to reconnaissance teams, artillery surveyors, and the forward units leading the charge.67
Recognizing immediately that GPS would be vital and most receivers could not use the encrypted military signal, the Pentagon on August 10, 1990—eight days after Iraq invaded Kuwait—disabled Selective Availability, the intentional degrading of the civilian signal to make it less accurate. The U.S. Air Force Space Command, which manages the satellites and ground control stations, had first activated the security feature only five months earlier, on March 25. Commanders reasoned that Iraq lacked weapons that could use GPS. However, the move opened the possibility of Iraqi troops acquiring and using commercial receivers for their own desert navigation, a fear that never materialized. The Air Force reactivated Selective Availability in July 1991, but within a decade turned it off again after a policy debate (see chapter 8).
Fig. 7.3. Manpack GPS receiver by Rockwell Collins. (Courtesy Rockwell Collins)
Fig. 7.4. AN/PSN-11 PLGR by Rockwell Collins. (Courtesy Rockwell Collins)
Anyone who has failed to update the software in their automobile navigation system and turned onto a new highway not shown on the screen has experienced the disorientation that using GPS with outdated maps can produce. When soldiers easily found other units in the empty desert during the Gulf War, they knew their destination’s coordinates. Without accurate, known coordinates, GPS could not lead troops to enemy targets. For this need non-GPS satellites, both military and commercial, made a critical difference in the war. Most Middle East maps the Defense Mapping Agency had available in August 1990 dated from the 1960s up to 1983.68 They used map reference systems predating the World Geodetic System 1984 (WGS-84), which GPS uses. (Cartographers periodically revise the underlying frame of reference, or datum, they use in mapmaking as methods for precisely measuring the planet improve.) B-52 bombers using GPS saw their gravity bombs fall consistently four hundred to six hundred feet short of their targets before figuring out that their inertial navigation systems were set to WGS-72, the older system from 1972.69
To solve the map problem, the Defense Department contracted with two private companies, American-owned Earth Observation Satellite (EOSAT) and SPOT Image, a French firm, to downlink wide-area digital satellite images to receiving stations in Saudi Arabia. This arrangement enabled military map-makers to create updated maps of the swath of land under a satellite pass within a matter of hours and distribute paper copies to troops in the field. These satellite images were not simply high-powered photographs made from space. They were multispectral images, derived from sensors capable of measuring wavelengths not visible to the eye. Multispectral imaging can detect heat and moisture, revealing water depth along coastlines, heated structures beneath vegetation, and tracks where equipment has traveled over the ground.70 EOSAT’s two Landsat satellites carried onboard GPS receivers, yielding precisely known orbits and thus images with highly accurate coordinates ready-made for use with GPS receivers.71 In the hunt for Iraqi SCUD mobile missile launchers, reconnaissance teams combined these assets with sensor data from three U.S. spy satellites of the Defense Support Program (DSP). The Pentagon began developing DSP satellites in the late 1960s to detect ballistic missile launches, primarily Soviet ICBMs. Desert Storm constituted the first “real-world ” test of t
he system, and although it was developed as a strategic asset, military analysts praised its value for tactical battlefield use.72 This use of satellite technology and digital image processing to provide real-time space surveillance of enemy movements was a technological milestone of the war. Together with GPS navigation, the overwhelming use of satellites led military leaders to proclaim the Persian Gulf War “the first space war. ”73
In a notable historical coincidence, Saddam Hussein launched his invasion of Kuwait on the same day, August 2, 1990, that the Air Force launched a GPS satellite into orbit. The Air Force launched two more satellites over the next three months, one on October 2 and another on November 26, bringing the constellation size to sixteen—still five short of the minimum required for continuous, worldwide three-dimensional coverage. Although some accounts erroneously describe these satellites as hurried into orbit to prepare for battle, the launches went up according to a schedule established well before the invasion.74 Neither the Air Force nor its suppliers could accelerate the launch program, given its complexity.75 However, the military took several steps to optimize the incomplete constellation for use in Iraq. Before the October launch, Space Command altered that satellite’s orbit to increase its visibility over the Persian Gulf and shortened the testing and preparation phase to get it into service faster.76 Tinkering with the constellation placed three satellites in view for nearly round-the-clock two-dimensional coverage (latitude and longitude, needed for ground and ocean-surface operations) and provided four satellites in view for three-dimensional coverage (latitude, longitude, and altitude, needed for airplanes) for about eighteen hours a day.77 At the time, three-dimensional coverage over Fort Bragg, North Carolina, for example, was available only fifteen hours per day.
During the crisis three satellites experienced problems that kept technicians of the 2nd Satellite Control Squadron (now called the 2nd Space Operations Squadron) busy designing workarounds.78 In August 1990 a twelve-year-old satellite (the third experimental Block I satellite, launched in October 1978) lost 40 percent of the power from its solar panels. By shutting down GPS signal transmissions and nonessential power uses during periods when the solar panels were in the earth’s shadow, ground controllers kept the batteries recharged and providing coverage over the Persian Gulf.79 On December 10 a stabilizer on another older satellite (the sixth Block I satellite, launched in April 1980) malfunctioned, and technicians devised a way to keep its solar panels angled toward the sun and its antennas pointed toward the earth.80 Ground crews kept it partially working during the war, but they permanently removed it from the constellation in March 1991.81 Also in December, the solar panels aboard the newest satellite, just launched November 26, became stuck in a fixed position, and ground controllers had to adjust them manually for the remainder of the war.82
In sum, the Persian Gulf War served as a sort of beta test for GPS-guided munitions but offered more of a full dress rehearsal for the system as a navigational aid for foot soldiers, ground vehicles, ships, and aircraft. For stateside ground crews managing the sometimes-balky satellites, it was a time of outright experimentation similar to what NASA faced during the moon race.
After the war the Pentagon concluded, “GPS was used more extensively than planned and met navigation and positioning requirements… . GPS should be considered for incorporation into all weapon systems and platforms. ”83 Those military leaders who argued in 1981 that “it may be difficult to understand the full potential until the system is deployed and the vast number of potential users are able to see what it will do for them ” undoubtedly felt vindicated.84 The war’s short duration and minimal casualties surprised almost everyone and left a legacy that makes it difficult to recall today the dire predictions and street protests that preceded it. A protester in front of the White House on the day the air campaign started questioned whether the carnage would leave anyone to liberate, remarking, “Bombs have no eyes. ”85 But many did have eyes, and many more bombs with eyes would follow. The Persian Gulf War marked a turning point in public expectations about acceptable collateral damage in conflict. The services rapidly began integrating GPS capability into precision-guided weapons, which saw increased use in each subsequent conflict. Whereas precision weapons constituted a negligible percentage of all ordnance expended in Vietnam, they represented 7 percent in Desert Storm; the share expanded to 60 percent during Operation Deliberate Force in the Balkans in 1995 and grew to 80 percent during Operation Allied Force in Yugoslavia and Kosovo in 1999.86
GPS applications continue to spread to “all weapons systems and platforms ,” including field artillery. In early 2012 General Dynamics and BAE Systems announced the successful demonstration of a “smart ” 81-mm precision mortar round made possible with GPS guidance and an in-flight control system.87 What could be next—a smart bullet?
The actual size of that “vast number of potential users ” first became evident in 1991. Others beyond the military took note of how GPS succeeded in the Persian Gulf War. The lopsided ratio of commercial to military receivers in Desert Storm foreshadowed a numerical difference that would become permanent.
8
Going Mainstream A Consumer Industry Is Born
Time is the greatest innovator.
Francis Bacon, “Of Innovations ,” The Essays, 1625
Hearing no more gunshots, voices, or footsteps for about an hour, Capt. Scott O’Grady decided to risk calling for help on his survival radio.1 He had spent most of the past three hours lying motionless, facedown in the dirt, with his gloved hands covering the exposed sides of his face and ears. The events that landed him in the Bosnian underbrush, hiding like a hunted rabbit, replayed in his mind, interspersed with reminiscences from his youth, lessons from his Air Force training, and scenarios for his survival. One moment he was cruising at twenty-six thousand feet, the next he was riding a fireball as his cockpit disintegrated around him. Four seconds after his F-16 fighter’s alarm system warned that targeting radar had locked onto him, a Serbian SA-6 surface-to-air missile slammed the plane’s belly, slicing the aircraft in two. He recalled spotting the yellow ejector-seat handle and tugging it, thrusting himself into the clouds and away from the burning debris that was traveling 350 mph. His long descent by parachute, observed by Serbian soldiers, left him only minutes to free himself from its harness and run from the grassy clearing where he landed to the cover of nearby woods. As their prey, he must be cautious with his survival radio lest its signal lead them to him before rescuers could arrive. He pressed the button and whispered his call sign, “Basher Five-Two ,” but all he heard was static.
O’Grady steeled himself for the possibility that he might have to spend days or weeks evading capture. He was the second pilot shot down enforcing the United Nations no-fly zone over the Balkan civil war, but he could not rely on the locals returning him to friendly forces as they had done previously for a British Harrier jet pilot. As the first U.S. pilot shot down since Desert Storm, he knew members of his 555th Fighter Squadron out of Aviano, Italy, the entire U.S. military, and much of NATO would be combing the skies, the airwaves, and intelligence sources for any sign he had survived. He needed to figure out his location and make his way to higher ground, where his radio would have a better chance of reaching search-and-rescue aircraft and where helicopters could more easily land. He must make that journey only in darkness, hiding under camouflage by day. O’Grady reached into the pocket of his survival vest and pulled out his GPS receiver, a Flightmate Pro made by Trimble Navigation.2 The three-by-seven-inch handheld unit operated on four AA batteries, but its four-line, backlit liquid crystal display was bright enough that he cupped his hands around it to keep the glow from piercing the darkness. Once the receiver acquired signals from three satellites, he had his position and oriented himself on a laminated topographic map from his survival kit. His target, a large hill, was about two miles south, but his stealthy advance, confined to the hours between midnight and 4:00 a.m., consumed that night, June 2, 1995, and the next four n
ights. He subsisted on rainwater, grass, leaves, and insects. At 2:07 a.m., June 6, he finally made radio contact with a fellow F-16 pilot from Aviano who was straining the jet’s fuel supply crisscrossing the skies in hopes of hearing something. Using his GPS unit, O’Grady was able to provide accurate coordinates. Military leaders rapidly mounted a rescue operation. Four and a half hours later, a platoon of Marines specially trained in tactical rescues used GPS guidance and extraordinary piloting to land two seventy-foot-long CH-53 Super Stallion helicopters in a small, fog-shrouded clearing about two hundred yards from O’Grady. He ran out of the woods, and they hauled him aboard one of them. The Super Stallions flew fast and low on the way out, drawing antiaircraft and small-arms fire. At least two shoulder-fired missiles whizzed behind them. Just before 7:30 a.m., the choppers landed on the USS Kearsarge in the Adriatic Sea to a hero’s welcome—one that would be repeated later at Aviano and again at the White House.
O’Grady’s dramatic story of survival and rescue offered the media and viewing public a welcome break from the O. J. Simpson murder trial and a grinding Medicare debate in Congress. More than half of people surveyed at the time said they were still closely following news about the Oklahoma City bombing two months earlier.3 Against this gloomy backdrop, O’Grady became an instant sensation. “High-Flying O’Grady Fills Hunger for Hero ,” read a USA Today headline above a story about how the crush of requests from reporters, agents, authors, and filmmakers was keeping all sixty Air Force public affairs staffers busy.4 Media interest endured, with additional bursts of attention when O’Grady later released a book and again on the one-year anniversary. News executives voted O’Grady among the top ten news stories of 1995.5 The coverage meant lots of publicity for GPS, but as reporters dug for different angles some asked why it took six days to find the downed pilot. After a private meeting with O’Grady, Rep. Robert Dornan, a California Republican who was chairman of the House Intelligence Subcommittee on Technical and Tactical Intelligence, declared O’Grady’s PRC-112 survival radio obsolete.6 Dornan, an ex–fighter pilot himself, revealed that O’Grady told him if he ever had to bail out again he would like to have a couple of cellular telephones.7 British pilots reportedly were already carrying them.8
GPS Declassified Page 15
