5 A COMMERCIAL MARKET EMERGES: 1983–1995

Before the downing of the Korean airliner, tests were showing that the civilian signal, alone, was providing much better accuracy than had been anticipated. The Department of Defense (DoD) realized that this signal could be used by an enemy to target US assets in a time of war. In June 1983, the DoD announced that a degradation of the civilian signal by selective availability (SA) would bring its accuracy back to the planned level. SA was implemented in 1990. Even with that restriction, as civil applications were beginning to emerge, resourceful engineers were devising ways to wring more accuracy out of the limited signals available to them. The better the accuracy, the more a civilian market could develop. Initially, the companies Magnavox, Rockwell, and Texas Instruments were the primary suppliers of user equipment, but by the early 1980s smaller companies were entering the field.