Stakes in the Sand: Surveying in the Gulf War

In 1990, US forces arrived in the Persian Gulf with a cornucopia of navigation technologies: not just GPS but also LORAN, TACAN, TERCOM (for cruise missiles), and inertial navigation systems which used laser, electrostatic, or mechanical gyroscopes, as well as old-fashioned manual tools like maps and compasses. So why were US surveyors heading off into the Saudi desert?

The surveyors were from the 30th Engineers Battalion (Topographic), which was deployed to provide map production and distribution, surveying, and terrain analysis services to the theatre. The survey platoon’s work was being done on behalf of the Corps and divisional artillery, which had their own particular navigational needs. Unlike fighter or helicopter pilots, field artillery gunners didn’t have the opportunity to see their targets and make last-minute adjustments to their own aim. Unlike bomber crews or cruise missiles, their fire missions were not planned well in advance using specialized materials. To provide precise positioning information to the guns, each artillery battalion in the Gulf was equipped with two Position and Azimuth Determining Systems (PADS), truck-mounted inertial navigation systems that keep an ongoing track of the unit’s positions. At the heart of the PADS was the standard US Navy inertial navigation system, the AN/ASN-92 Carrier Inertial Navigation System (CAINS).

Like all inertial navigation systems, PADS had a tendency to drift over time. That meant that it required regular refreshes using a pre-surveyed location, or control point. The initial specifications for PADS were to achieve a horizontal position accuracy of 20 meters over 6 hours and 220 kilometers. Actual horizontal accuracy seems to have been far better, more like 5 meters. One reason for the high accuracy was that, unlike an airplane, the vehicle carrying the PADS could come to a complete stop, during which the system detect and compensate for some of the errors by the accelerometers in the horizontal plane.

Unfortunately, the US had exactly one control point in Saudi Arabia, at Dharan airbase (Army Reserve historian John Brinkerhoff says this and several other point surveyed were done with “Doppler based methods.” I assume that means using the TRANSIT satellite system, which determined location on the basis of Doppler shift). Starting from that control point, the 30th’s surveyors extended a network of new control points northwards and westwards towards the Iraqi border. Conventional line-of-sight survey methods would have been too slow, but the surveyors had received four GPS receivers in 1989 and soon got more from the Engineer Topographic Laboratories to equip a follow-up team of surveyors. Eventually, their survey covered 10,000 square kilometers and included 95 control points. Relative GPS positioning took about two hours (according to Brinkerhoff) and offered accuracy to about 10 centimerers (compared to 17 meters for regular GPS use). Absolute positioning – done more rarely – required four hours of data collection and provided accuracy of 1–5 meters.

When the ground war began on 24 February 1991, the two survey teams tried to stay ahead of the artillery, which meant driving unescorted into the desert and marking new control points with steel pickets with reflectors (for daytime) and blinking lights (for night-time). Providing location data through headquarters was too slow, so the surveyors took to handing it directly to the artillery’s own surveyors or just tacking it to the pickets. By the ceasefire on March 1 they had surveyed all the way to 30 km west of Basra. Where the artillery outran the control points they used their own GPS receivers to make a “good enough” control point and reinitialized the battalion PADS there, so all the artillery batteries would at least share a common datum. One thing PADS could do and GPS couldn’t was provide directional information (azimuth), so units that outran their PADS capabilities had to use celestial observations or magnetic compasses to determine direction.

What the 30th Battalion and the artillery’s surveyors did in the Gulf was different enough from traditional survey methods that the some in the army already used a different phrase, “point positioning,” to describe it. In the 1968–1978 history for the Engineer Topographic Laboratories, which designed army surveying equipment, PADS was one of three surveying and land navigation instruments singled out as part of this new paradigm (the others were a a light gyroscope theodolite with the acronym SIAGL and the Analytical Photogrammetric Positioning System).

Brinkerhoff tells the story of the 30th’s surveyors as the meeting of the high and low tech, but the work really relied on a whole range of technology. Most of the GPS surveying was relative positioning that was anchored to previous Doppler surveying. Position and azimuth information was carried forward by inertial navigation, and the position of the firing battery was paired with target information from a forward observer equipped with GPS, an inertial navigation system, or a paper map or from aerial photography which could be interpreted using the aeroplane’s own navigation system or a photointerpreter’s tool like APPS. GPS surveying and navigation did not stay wrapped up with all these other navigational tools for long. The technology was flexible enough to be used in place of many of them. But in the early 1990s, GPS’s success was contingent on these other systems too.

Sources Notes: The story of the 30th and its surveyors appears in John Brinkerhoff’s monograph United States Army Reserve in Operation Desert Storm. Engineer Support at Echelons Above Corps: The 416th Engineer Command (printed in 1992). Further details appear in the Army Corps of Engineers history Supporting the Troops: The U.S. Army Corps of Engineers in the Persian Gulf War (1996) by Janet A. McDonnell and “The Topographic Challenge of DESERT SHIELD and DESERT STORM” by Edward J. Wright in the March 1992 issue of Military Review. Reflections on how the artillery used PADS and GPS in the Gulf come from the October 1991 issue of Field Artillery, a special issue on “Redlegs in the Gulf.” Technical details for PADS are from the ETL History Update, 1968–1978 by Edward C. Ezell (1979).


A Tale of Two Keystone States

An auxiliary crane ship, the SS Cornhusker State, in 2009. US Navy by Petty Officer 1st Class Brian Goy. DIVIDS Photo ID 185724.

In the later years of the Cold War, the US Navy recognized the need to revitalize its seagoing transport capacity. During the Second World War, the military had built a massive fleet to support transatlantic and transpacific campaigns. Mothballed after the war, much of it had rotted away by the time reconstruction began under presidents Nixon and Carter and accelerated under President Reagan. One necessity for the new fleet was equipment to move cargo – especially containers – from ship to shore. After experiments with lifting by helicopter or balloon, the Navy settled on fitting a series of cargo ships with heavy cranes to unload cargo in ports that lacked the necessary infrastructure. The first ship to be converted was the SS President Harrison, previously operated by American President Lines, which was renamed the SS Keystone State (T-ACS-1) upon completion of its refit in 1984.

The Barge Derrick Keystone State (BD-6801) being towed by two Army Small Tugs during an exercise at Joint Base Langley-Eustis, Va., Aug 6, 2013. (U.S. Army photo by Spc. Cal Turner/Released) DIVIDS ID 990511.

Confusingly, the T-ACS-1 is not the only US military crane watercraft named the Keystone State. In 1998, the US Army launched a engine-less crane barge BD-6801 with the same name, chosen to honor the 28 soldiers from Pennsylvania’s 14th Quartermaster Detachment killed in a SCUD attack during the first Gulf War (in this instance, BD stands for Barge Derrick). Operated by the Transportation Corps, the BD-6801 was built to help unload military cargo in any of the many ports around the world unequipped to handle the cargo. It carries a single crane with a reach of 175 feet and a lift capacity of 115 long tons which, unlike the cranes on previous army barges, is able to lift a 60 ton M1 tank off of a cargo ship.

Between 1985 to 2005, at least one Army floating crane like the Keystone State was always aboard the MV American Cormorant, a float-on/float-on (FLO/FLO) heavy lift ship at Diego Garcia that carried a package of Army watercraft for operating a damaged or unequipped port. The American Cormorant and its cargo deployed to many major crises as part of the army response, including the first Gulf War and Operation RESTORE HOPE in Somalia. Until the launch of the Keystone State, the crane barge carried aboard the American Cormorant was one from the BD-89T class, with an 100 foot reach and an 89 long ton (100 short ton) capacity.

The American Cormorant en route to the Gulf. Note the two BD-89T cranes on-board, only one of which was used in operations. From Operations Desert Shield and Desert Storm: The Logistics Perspective (Association of the United States Army Institute of Land Warfare, 1991), p.12. Courtesy of the AUSA website.

It was a BD-89T barge, the Algiers (BD-6072), which was deployed to be used by the Army 10th Transportation Battalion (Terminal) during the Gulf War. In addition to performing more than 1,500 lifts in Saudi ports, the Algiers was used to help clear damaged Kuwaiti ports of obstructions – harbor clearance being a mission shared between the US Army and Navy. After having built-up an extensive salvage force after the Second World War, changes to salvage doctrine meant the US Navy only sent one salvage ship and no heavy-lift gear to the Gulf. Commercial salvors being paid by the Dutch government took up much of the slack, but there were limits to what the contractors could do. With rental fees for barges and cranes running as much as $150,000 a day for a 600 ton Ringer crane barge, the Americans ended up mostly going without the heaviest equipment. The biggest harbor clearing lift involving the Algiers was a sunken Iraqi Osa II missile boat in the Kuwaiti port of Ash Shuaybah. Though small by seagoing standards, the Osa II was 127 feet long and displaced almost 200 tons in standard load. Even in combination with a quayside 140 ton crane, the crane barge couldn’t lift the ship whole. Only after army divers cut off the still-life missile launchers could the boat be raised. Looking back at the operation in the navy after-action report, perhaps with a little bit of envy, one of the navy salvage engineers called the army crane “very workable.” Other sunken craft the divers lifted at Ash Shuaybah, with or without the help of the crane, included a 90 foot sludge barge and two other boats.

The deployment of the Algiers during the first Gulf War is only the tip of the iceberg when it comes to the military roles played by American floating cranes, which since the conversion of the battleship Kearsage into Crane Ship No. 1 have worked to construct warships, salvage sunken submarines, and clear wrecks from the Suez Canal.

Source Notes: Much of the information for this post came from various sources around the internet, and in particular the website for the US Army Transportation Corps’ history office. The Corps’ 1994 official history, Spearhead of Logistics, was also useful. Details on the salvage operations during the Gulf War came mostly from the two-volume US Navy Salvage Report: Operations Desert Shield/Desert Storm, printed in 1992 and available online at the Government Attic (volumes one and two); the report’s chronology was the only place I was able to find which US Army crane barge was actually operated during the war.

A Hidden Map Between Sensor and Shooter, Postscript: Why Beale AFB?

Describing how he used U-2 radar imagery to generate precision target coordinates during the 1999 Kosovo war, Vice Admiral Daniel J. Murphy, Jr. explained that:

I walked into the intelligence center and sitting there was a 22-year-old intelligence specialist who was talking to Beale Air Force Base via secure telephone and Beale Air Force Base was driving a U–2 over the top of this spot. The U–2 snapped the picture, fed it back to Beale Air Force base where that young sergeant to my young petty officer said, we have got it, we have confirmation. I called Admiral Ellis, he called General Clark, and about 15 minutes later we had three Tomahawk missiles en route and we destroyed those three radars.

The obvious question, at least for me, was why Beale AFB in Calfornia was “driving” the U-2 when the aircraft was flying from Istres, France, and the air operations center was in Aviano, Italy.

The explanation took some digging to locate. It begins, more or less, with the first Gulf War. During Operation Desert Shield, the US Air Force deployed a mix of U-2 and TR-1 reconnaissance aircraft (essentially the same airplane, with different designations depending on whether they had been built for strategic reconnaissance or for the European theatre) to King Fahad Air Base in Taif, Saudi Arabia. The U-2/TR-1s being used at the end of the Cold War had been upgraded to carry a range of sensors that included film cameras, electro-optical sensors (essentially a TV camera on steroids), radars, and ELINT and SIGINT receivers. The most important of those sensors for Desert Shield/Desert Storm were the ones that could use a data-link to deliver their information in real-time. U-2s from the United States carried the SENIOR YEAR electro-optical sensor, while TR-1s from Europe carried the Advanced Synthetic Aperture Radar System (ASARS-2).

Since the Air Force had had no plans to deploy the U-2 to the Middle East, it was entirely unready to receive that information in the theater. To connect to a ground station by data-link (often called being “on tether”) the airplane needed to be within 220 miles of a ground station. Built for the Central European front, the TR-1/ASARS combination was designed to be “tethered” to a ground station in a bunker beneath an old missile maintenance facility (“Metro Tango”) near Hahn air base in West Germany (AW&ST, 4 June 1990). Without an equivalent ground station there was no way to use the radar in the Middle East.

Luckily, the US Army had wanted its own access to the ASARS picture and had built prototype mobile ground station, the Tactical Radar Correlator (TRAC), which could be deployed to Saudi Arabia. The SENIOR YEAR electro-optical system also had an experimental ground station van, code-named SENIOR BLADE, which went to Saudi Arabia too.

The Air Force was equally unprepared to process film from the U-2’s optical cameras. Before either the HR-239 (H-cam) or the Intelligence Reconnaissance Imagery System III (IRIS-III) could have their photos processed in theater the Air Force had to refurbish the Mobile Intelligence Processing Element (MIPE) that had been designed for use with the SR-71 and been mothballed when that airplane was taken out of service. (All these problems, and the eventual solutions, are described in the 9th Reconnaissance Wing’s history of U-2 operations during Desert Storm.)

The experience with Desert Storm and the collapse of the Soviet Union convinced the US military that it needed the tools to make use of reconnaissance systems like the U-2 in any region. By August 1991, the Air Force had already announced the creation of the Contingency Airborne Reconnaissance System (CARS), a twenty-seven shelter ground station that was established at Langley Air Force Base in 1992 to receive imagery and signals not just from U-2s but also from drones and other reconnaissance aircraft. Other ground stations, at Beale AFB in California and Osan in Korea, were established in 1994 and the whole program was renamed the Distributed Common Ground System in 1996. The Langley AFB station, known as Deployable Ground Station (DGS) 1, deployed to Guantanamo Bay and Saudi Arabia. The Beale station, DGS-2, were sent to Europe during the US/UN intervention in the Balkans.

The most important component of the multi-shelter DGS was the Mobile Stretch (MOBSTR) relay that transmitted signals from an “on tether” U-2 to somewhere else in the theater, or further away. MOBSTR was important because a DGS was big: in 1996 the Air Force said it would take seven C-5 Galaxy transports; by 2004 the number had ballooned to seventeen. Using the relay meant that more personnel could work from the US rather than in the theater of operations, substituting bandwidth for troops on the ground.

According to William M. Arkin’s new book, Unmanned, further impetus to keep the DGS in the continental US came from the Khobar Towers bombing in 1996. 24 members of DGS-1 were among the Air Force personnel killed or injured in the terrorist attack on US Air Force housing in Saudi Arabia. “Reachback,” as the use of staff in the US was called, only grew during the invasions of Afghanistan and Iraq. According to Air Force Magazine, only 90 of the 2,000 airmen assigned to DGS-1 and 2 were actually sent to the Middle East. The remainder, operating from Langley and Beale, made more than 30,000 intelligence reports and identified more than 1,000 targets during Operation Iraqi Freedom alone. The phenomenon became so widespread that by 2009 David Deptula, the Air Force deputy chief of staff for intelligence, surveillance, and reconnaissance (ISR) and a senior planner during the Gulf War air campaign, could argue for killing the term and replacing it with “distributed operations,” since so many ISR operations were spread over multiple sites around the world.

Arkin’s book has some idiosyncrasies that annoyed me, such as its repetitious references to the Epic of Gilgamesh. It won’t make Richard Whittle’s Predator or any of the other good recent books in this area obsolete. But it has some interesting things to say when it focuses not on platforms or policies, but on the middle-ground – budgeting, “black project” acquisition processes, and institutional politics – that lies between them and shapes how American has been fighting its war over the last fifteen years. Plus it gave me that link in the chain of how U-2 operations got spread across the whole world.

A Hidden Map Between Sensor and Shooter: The Point Positioning Data Base, Part Two

Back to Part One

One part of the long pre-history surrounding the deployment of GPS-guided bombs began in the late 1960s with US Army Corps of Engineers and a research project to improve the accuracy of American field artillery. The Analytical Photogrammetric Positioning System (APPS) was a tool to calculate the coordinates of a target seen on reconnaissance photography. Introduced into service in the mid-1970, APPS and the geo-referenced imagery that it used (the Point Positioning Data Base, or PPDB) proved so useful that they were borrowed by US Air Force and Navy airstrike planners too.

The desire to fix targets from aerial photography and strike them with precision was hardly unique to APPS’s users. The Air Force also had a system for calculating target coordinates under development. The Photogrammetric Target System (PTS) was part of a far grander system for detecting, locating, and destroying enemy surface-to-air missile (SAM) sites called the Precision Location and Strike System (PLSS). Unlike APPS, which printed out target coordinates for human use, the proposed PTS was a fully computerized system that would transmit the coordinates to PLSS’s central computer somewhere in West Germany or the United Kingdom, where they would be converted into guidance instructions for the 2,000-lb glide bombs that were going to be the sharp end of the system.

The TR-1, a renamed U-2 reconnaissance plane, was the aerial platform for the PLSS system. (U.S. Air Force Photo by Master Sgt. Rose Reynolds)

The TR-1, a renamed U-2 reconnaissance plane, was the aerial platform for the PLSS system. (U.S. Air Force Photo by Master Sgt. Rose Reynolds)

You can see how PTS’s fortunes waxed and waned by following the annual briefings on PLSS that the Air Force gave to Congress. What began in 1973 was gradually scaled back as PLSS’s own funding declined. Plans for a manual prototype PTS were cancelled when it became clear that APPS could do the same job, and the system disappeared from the briefing in 1980.

Much of the imagery for point positioning came from mapping cameras on the KH-9 HEXAGON satellite. NRO photograph courtesy Wikimedia.

Much of the imagery for point positioning came from mapping cameras on the KH-9 HEXAGON satellite. NRO photograph courtesy Wikimedia.

While the Air Force was experimenting with PTS and APPS to plan aerial attacks, PPDB was expanding in importance to become part of the targeting process for non-nuclear Tomahawk missiles being operated by the US Navy. Simultaneously, crises with Iran and the demands of the Carter Doctrine drove the expansion of PPDB coverage in the Middle East to 930,000 square nautical miles by 1981.

That meant that when Iraq invaded Kuwait in 1990 the US had 100% PPDB coverage of the theater, better than the coverage with either 1:50,000 topographical maps or 1;250,000 Joint Operations Graphic-Air. Unfortunately, the PPDB imagery was woefully out of date, forcing the Defense Mapping Agency (DMA) to make PPDB updates part of its vast cartographic build-up for Operation Desert Shield. That included 30 new PPDB sets (of 83 requested), 26 video PPDB sets, and 7,972 target coordinates.

Despite those deliveries, the obsolescence of PPDB imagery was noticed during Operation Desert Storm. The annual official history of 37th Fighter Wing – which flew the F-117 stealth fighter during Desert Storm – complained that:

Spot imagery was not of sufficient high resolution to support the technical requirements of a high technology system such as the F-117A Stealth Fighter. And, the available Analytical Photogrammetric Positioning System (APPS) Point Positioning Data Base (PPDB) was grossly outdated. It was not until the last week of the war that more current PPDBs arrived, which was too late to have an effect on combat operations.

After 1991, the need for precise target coordinates grew alongside the spread of precision guided weapons that needed those coordinates, which meant that what had begun as an Army instrument became more and more vital to aviation. A 1994 naval aviation handbook reminded users that “reliable target coordinates come only from a limited number of classified sources,” including the Defense Mapping Agency’s “Points Program” (which accepted requests by phone or secure fax) and APPS systems carried on aircraft carriers.

Unlike laser or electro-optical-guided bombs that homed in on a signature that their target emitted or reflected, bombs and missiles guided by GPS simply fly or fall towards the coordinates they are given. Widespread deployment during the bombing of Serbia in 1999 (Operation ALLIED FORCE) therefore meant a vast demand for precise target coordinates.

The Point Positioning Data Base, now provided in digital form rather than as a film chip/magnetic cassette combination, was an important source of those coordinates because it provided not just two-dimension latitude/longitude coordinates but also elevation. In a desert environment like Iraq, a bomb dropped from above could more or less be assumed to hit its target no matter how large the gap between the actual elevation of the ground. Where the terrain was more varied, however, aiming to high or too low could cause the bomb to slam into a hill short of the target or fly right over it and land long. Securing that elevation information from aerial photography was known as “mensuration.”

Though APPS was a computerized tool, it used film chips rather than digital imagery. To take the entire system digital, the National Imagery and Mapping Agency (which had absorbed the Defense Mapping Agency in 1996) developed a computer workstation called DEWDROP that could provide mensurated coordinates using the Point Positioning Data Base. That was followed a few years later by a similar system called RainDrop. In February 1999, a little over a month before ALLIED FORCE began, the Air Force committed to buy 170 RainDrop systems for $1.8 million from Computek Research, Inc. (Here’s the press release.)

During ALLIED FORCE, mensurated coordinates were needed for Tomahawk, CALCM, and SLAM missiles, as well as the JDAM bombs being carried by the first B-2 stealth bombers. To get them, the air operations center in Vincenza, Italy had to reach back to analysts in the United States, which was where the mensuration workstations were located. Here’s how Vice Admiral Daniel J. Murphy, Jr. describes the process of acquiring them, starting from a rough fix provided by an ELINT satellite:

So I walked into the intelligence center and sitting there was a 22-year-old intelligence specialist who was talking to Beale Air Force Base via secure telephone and Beale Air Force Base was driving a U–2 over the top of this spot. The U–2 snapped the picture, fed it back to Beale Air Force base where that young sergeant to my young petty officer said, we have got it, we have confirmation. I called Admiral Ellis, he called General Clark, and about 15 minutes later we had three Tomahawk missiles en route and we destroyed those three radars.

About a year later the Air Force ordered another 124 RainDrop systems. (Another press release.) Three months later, Northrop Grumman bought Computek for $155 million in stock.

ALLIED FORCE was confirmation for many observers that coordinate-guided weapons were the wave of the future. Tools like PPDB were necessary infrastructure for that transformation.

Forward to Part Three

The Balloon That Saved The Emir

In October of 2015, a tether balloon (or aerostat) that was part of the US Army’s Joint Land Attack Cruise Missile Defense Elevated Netted Sensor (JLENS) system broke free from its moorings at the Aberdeen Proving Ground in Maryland. The 243-foot-long helium balloon led the military on a merry chase, taking out power lines with its mooring cable, before settling to the ground several hours later.

Embed from Getty Images
A JLENS balloon like the one that got loose over Maryland.

The JLENS balloon’s runaway escape was an embarrassment for a program that’s been labelled a “zombie,” “costly, ineffectual, and seemingly impossible to kill,” but it was hardly the first time a military aerostat has gotten loose to wreak havoc. In 1981 the first military aerostat to enter service since the end of the Second World War, a blimp with the project codename SEEK SKYHOOK and the unofficial nickname “Fat Albert,” got free of its tether on Cudjoe Key in Florida and almost lifted a fishing boat that tried to corral it free of the water before being shot down by two Air Force jets.

The SEEK SKYHOOK aerostat, which entered service in 1974, inaugurated a second era of tethered military balloons that’s already about as long as the technology’s first era – which lasted from the Japanese use of an observation balloon over Port Arthur in 1904 until the decommissioning of the barrage balloons operated during the Second World War.

SEEK SKYHOOK was an air search radar (an AN/DPS-5, to be precise) deployed to the Florida Keys to offer better warning of aircraft approaching from Cuba. Most subsequent aerostats were also intended for air defense. That included the Low Altitude Surveillance System (LASS) purchased by Kuwait in the late 1980s to add to their air defense system. The LASS, one of which was also purchased by Saudi Arabia, combined a 71-meter-long balloon built by TCOM, L.P. with a Westinghouse AN/TPS-63 radar like that used for short-range warning by the US Marine Corps. Though the LASS was intended to spot low-flying aircraft its position at 10,000 feet meant it had some capacity to watch ships or ground vehicles too.

A TCOM 71M LASS aerostat. From Flight International, 11/17 Aug. 1993, p.40

A TCOM 71M LASS aerostat. From Flight International, 11/17 Aug. 1993, p.40

That additional capacity meant it played an important part in the early hours of the Iraqi invasion of Kuwait in 1990. The LASS system was still in the testing phase, being operated by a mixed team of contractor personnel and Kuwaiti air force officers. Early on the morning of August 2, the operators watched “a big burst of light – a solid line of target returns” crossing the border. Clifford Gobbitt, a TCOM systems engineer on duty, recalled that “there was so much metal, it was saturating the display.” A few hours later the TCOM staff turned the balloon and its radar over to the Kuwaiti Air Force and began the process of extracting themselves from what was about to become a war zone. A few months later, TCOM’s vice president of marketing told Aviation Week and Space Technology that “the TCOM aerostat system got the first detection of the invasion, and that warning allowed the Emir and his family to escape.” The balloon was destroyed within the next few days, but the Kuwaitis must have been satisfied with the results. Once the war was over they put in an order for an upgrade system of the same type.

The Kuwaiti experience on the eve of the Gulf War was a preview of sorts for what would be expected from one of the stand-out successes of the war, the Joint Surveillance Target Attack Radar System (JSTARS). Like the Kuwaiti LASS, JSTARS used an aerial radar to track the movement of enemy ground forces. Unlike the LASS, JSTARS was built for that task and that task only. Only two experimental aircraft were ready when the war began, and interpreting their information was apparently not much easier than reading the radar returns the TCOM technicians had seen. Colonel Martin Kleiner, the Army’s project manager, recalled that “the aircraft was airborne, it was down-linking radar and the ground stations were receiving it. Quite frankly, we had no idea what we were looking at. Our application of the system was pretty much being developed on the fly.” Still, they proved themselves indispensable in several battles. After the war, Air Force Chief of Staff General Merrill McPeak said “We will not ever again want to fight without a JSTARS kind of system.”

August 2nd was also the swan song of balloon-borne ground surveillance radar. Though JSTARS and similar programs spawned a series of aircraft-mounted radar systems, the surveillance aerostats used by the US government in places like Afghanistan, Iraq, and the US border with Mexico tend to be designed for low-intensity conflicts and equipped with video cameras rather than radar.

Global Positioning Synecdoche: An Interim Update

The next installment about guidance and navigation during the Gulf War is a little delayed since it’s sprawled from a brief description of a cruise missile targeting aid to cover photogrammetry and mensuration tools from the late 1960s to the near-present. That’ll take some wrangling to bring back under control.

In the meantime, I’ve been thinking about some of the trends in what I’ve already written. The systems that became associated with victory in the Gulf (GPS, cruise missiles, laser-guided bombs, etc.) were all reliant on a range of less obvious technologies. TERCOM guidance, for example, required accurate satellite mapping that was itself an offshoot of satellite reconnaissance photography. Few of the systems, either the marquee technologies or the supporting ones, were designed with their eventual use in mind. Only luck or serendipity brought them together in the way that led to the success. The commercial GPS receivers that were so popular during the war existed because President Reagan had made a political point by opening the system to civilian use. Ring laser gyroscopes in aircraft navigation systems were available because Boeing’s commercial aviation division had made a big bet on the technology when the Defense of Department had balked at widespread adoption in the late 1970s. What I’m working on, the story of the Point Positioning Data Base and Analytical Photogrammetric Positioning System, is a similar case of technology created for one mission that proved far more useful, in conjunction with other equipment, for a different one.

We’ll see how long this series lasts, but I’m realizing that the list of systems that deserve some coverage is pretty long. Reading about long-range radionavigation like Loran-C pointed to the fact that I can find almost nothing about Tactical Air Navigation (TACAN). The planning tools for each day’s airstrikes are more discussed, but there’s plenty to say about how they came into existence. I’ll have to figure out where to go after that.

The Other Lasers of the Gulf War, Part Three

Part of a three-part series on the development of the laser gyroscope and its military use. Back to Part Two or Part One

Meaning and Legacy
Sociologist Donald MacKenzie, whose book Inventing Accuracy remains pretty much the classic history of inertial guidance development, convincingly argues that there was nothing inevitable about the choices made in the development of these inertial navigation systems. After all, despite widespread military adoption in the mid-1980s, the laser gyro was hardly the only game in town. Despite granting $135 million in development funds to design laser gyro guidance systems for the abortive Small ICBM (aka the “Midgetman”) the US Air Force decided that the laser gyro wouldn’t meet the requirements and borrowed the mechanical gyro system used in the MX ballistic missile instead. Likewise, the F-117 stealth fighter entered service with the precise but off-the-shelf SPD/GEANS INS. Instead, the decisions to fund, buy, and develop technologies like the laser gyro reflected the strategic plans, aspirations, and expectations of technologists and users, as well as sheer coincidence. Charles Stark Draper was right that mechanical gryos would continue to be and to become more accurate for the foreseeable future, but the laser gyro had the promise of a radical technological breakthrough and the sexiness of the very word laser.

The case of the laser gyro also shows how tough it is to pigeonhole a technology as “military” or “civilian” in its origins. Is the laser gyro military technology because much of the initial development money came from military sources? Is it civilian technology because it was the commercial airliner industry that first bought them en masse and made the transition from prototype to standardized product? Does tracing that history help us understand how precision navigation contributes to either sphere of action?

I started looking at the navigational tools applied during the first Gulf War because of Ingrid Burrington’s article on a 1990s protest against GPS because of its military origins (which I commented on here). Writing in the Atlantic, Burrington describes how activists Keith Kjoller and Peter Lumsdaine snuck into a Rockwell International facility in Seal Beach, California and used wood-splitting axes to smash up nine GPS satellites “to slow the deployment of this system (which) makes conventional warfare much more lethal and nuclear war winnable in the eyes of some.”

Interviewed by Burrington twenty-two years later, Lumsdaine was firm that GPS remains “military in its origins, military in its goals, military in its development.” What I wanted to investigate was what that meant in comparison to all the other systems that contributed to the type of aerial campaign launched in the Gulf. Along the way examples dropped into my lap of similar protests against those technologies. Mass opposition to the installation of transmission towers for the Omega radionavigation aid, as opposed to the more precise and more military-used Loran-C. The bombing of a factory for the inertial navigation systems of the Air-Launched Cruise Missile.

Trying to parse the role of the laser gyroscope in the first Gulf War is tough because it was so widespread. I can’t find anyone who writes about using an INS in the Gulf, perhaps because it was such a mundane occurrence. But the development path of the laser gyro shows that calling it a military technology involves making some presumptions about whose contributions mattered. Early inertial navigation was bought and paid for by the military because of its use in strategic (i.e. nuclear) weapons, but within twenty years had trickled down into commercial aviation. The laser gyro was similarly funded in its development by the armed forces, but they went on to shun it as an initial product because it was not yet superior to what they had in service. It was commercial aviation, the previous trickle-down beneficiary, who put up the funds to turn the laser gyroscope into a practical and widespread device. This was technology that was normalized as civilian before it was normal in the military.

Perhaps not coincidentally, alongside the GPS receiver you probably carry in your pocket you also have a set of accelerometers and gyroscopes. Most modern smartphones include microelectromechanical (MEMS) inertial sensors to measure orientation and motion, which is used to do things like change the screen orientation when you turn your phone sideways. (This is a very cool video that explains how a MEMS accelerometer works and how it is manufactured.) Should you be concerned that you’re carrying around a miniaturized, albeit inaccurate, version of the technology mounted on the first ICBMs? Quite possibly, considering that researchers have shown how the gyroscopes in a phone could be used to eavesdrop on nearby audio or keystrokes. But probably not because it was the US Department of Defense that funded its origins.

Source Notes: Not much has been written about the history of gyroscope development. The notable exception is Donald MacKenzie’s exceptional history Inventing Accuracy: A Historical Sociology of Nuclear Missile Guidance. MacKenzie’s history of the laser gyroscope is a separate article, “From the Luminiferous Ether to the Boeing 757: A History of the Laser Gyroscope” (Technology and Culture, July 1993). Paul G. Savage’s paper “Blazing Gyros – The Evolution of Strapdown Inertial Navigation Technology for Aircraft” (originally published in Journal of Guidance, Control, and Dynamics, May/June 2013) was also very useful. Given the absence of broader histories, Flight magazine’s archive was very useful for filling in some details.