What did a pilot in the Soviet Union’s air defense forces have to do with the US military’s stunning victory over Iraq in the first Gulf War? By a series of remarkable coincidences, it was a flight that Major Osipovich made in late 1983 that led to US troops having the ability to navigate across trackless desert with confidence in 1991.
The story starts in 1957 with the launch of the Sovet Union’s first satellite, Sputnik. Listening to the famous “beep-beep” signal being broadcast from the satellite, scientists at Johns Hopkins University’s Applied Physics Laboratory realized that they could use the doppler shift in the signal created as the satellite orbited the earth to calculate its position (doppler shift is the change in frequency of a signal as its source moves towards or away from the observer/listener; you hear it when the high-pitch whine of an oncoming train or police siren becomes lower after it goes past).
The scientists at Hopkins were already working for the US Navy on some missile guidance problems, so they suggested that by reversing what they had discovered the Navy could use satellites for navigation. With Sputnik, the scientists at APL had used the doppler shift from a known location on earth to determine the orbit of a satellite. The new system, code-named Transit, would use the doppler shift from a satellite in a known orbit to determine the location of a ship on earth. This was a big deal for the Navy because it was about to send its first ballistic missile submarines to sea. To hit their targets in Russia, the Polaris missile they carried needed precise data on its starting location, and the inertial navigation systems the submarines carried weren’t enough. The Navy and APL moved fast; the first prototype Transit satellite reached orbit in 1960 and the system was operational by 1964.
Because it could be used almost anywhere on earth Transit was a navigational breakthrough, but there was still room for improvement. You could only get a Transit fix when one of the satellites was overhead (which wasn’t often enough), and the accuracy (within roughly 100m) was good enough for ships but not for planes (which also needed a fix in three-dimensions, not just two). All this led the US Air Force to start working on a successor in the early 1970s. The Global Positioning System (GPS) used some of Transit’s basic principles but was to have far more satellites and use synchronized atomic clocks rather than doppler shift to determine location. Each satellite now transmitted both its orbital information and the precise moment of transmission. Knowing the time lag gave the receiver the distance from the satellite, and combining that information for three or more satellites gave a precise three-dimensional fix – the one place on earth that combination of signals was possible. The first prototype GPS satellite went into orbit in 1978 and by 1991 there was a functioning, but incomplete, constellation of Block II satellites.
When the US went to war against Iraq, a small but growing number of aircraft and ships had built-in GPS receivers that gave them 3-D positional fixes to within a few meters. The Army, on the other hand, only had a few mobile GPS receivers. The AN/PSN-8 was officially a “backpack” unit, but weighed 8 kg. and cost $45,000. What made GPS so important in 1991 was that it was available to almost every combat unit and convoy going into the desert, usually in a form that the average soldier could slip into an oversize pocket – and this is where Major Ospiovich comes into the story.
Osipovich was the pilot who, on September 1st, 1983, shot down Korean Air Lines Flight 007 over the Sea of Japan. The tragedy, which killed 269 people, would have been avoided if the airliner hadn’t deviated from its planned flightpath and overflown Soviet territory. In response, US President Ronald Reagan guaranteed that the military’s new GPS satellites would be available for civilian use, free of charge, as well. On its own, this wasn’t enough to change navigational history. Transit had also been made available to civilian users in the early 1970s, and there were about 36,000 civilian users on land and sea by the time Reagan made his announcement. But one month after Reagan’s announcement, Apple Computers unveiled the Macintosh 128K in a Superbowl commercial directed by Ridley Scott. The Macintosh was irrelevant to military computing, but it was a consequence of the growing power of microprocessors, which would make all sorts of new military applications possible.
The first commercial GPS receivers were enormous: the Macrometer V-1000 weighed 91 kg and needed a helicopter to move it from site to site. One of the smallest, the Texas Instruments TI 4100, still weighted 25 kg and doubled as a hand warmer in the field! This was because they still had lots of analog components to process the GPS signal. Switching to digital components slimmed down GPS receivers fast. With funding from the Defense Advanced Research Projects Agency (DARPA), Rockwell Collins- who was providing all the military’s GPS receivers – built an all-digital miniaturized GPS receiver nicknamed “Virginia Slims,” because it was the size of a pack of cigarettes. This was only possible using advanced Gallium Arsenide (GaAr) chips, but other manufacturers weren’t far behind with more conventional solutions. While Rockwell was commercializing “Virginia Slims” into its NavCore V, Magellan introduced the NAV 1000 (weighing 850g) and Trimble the 1.5kg Trimpack. When war broke out in 1991, the Army bought armloads of both of these portable receivers “off the shelf.” The military called them the Small Lightweight GPS Reciever (SLGR, or “slugger”), and it bought almost 10,000 and shipped half of them straight to the Gulf. Cheap handheld receivers made GPS as ubiquitous as the MRE or the Humvee, and led to the US military putting GPS into almost everything. The first GPS-guided weapons were a batch of Conventional Air-Launched Cruise Missiles (CALCM) fired at the start of DESERT STORM, but today the GPS-equipped Joint Direct Attack Munition (JDAM), is probably the US Air Force’s most frequently used smart bomb. When the US went back into Iraq in 2003, GPS was also a key tool for preventing fratricide and keeping commanders aware of their troops’ locations through the Blue Force Tracker. All this war-winning technology was a consequence of the tragedy of KAL 007 as much as it was the result of careful planning and engineering.