Going Public - GPS Declassified: From Smart Bombs to Smartphones - page 93

committed users had remained static through 2000, the military would have
spent about a half-million dollars per receiver to provide gps service. Of course,
as the system reached fruition over the next two decades the number of mili-
tary users rose significantly, and the number of commercial users surpassed
those in the military.
Down to Earth
The tiny portion of those first receivers allocated to the Defense Mapping
Agency—ifty in all, or less than 1 percent—was disproportionate to their sig-
nificance. Indeed, land surveying emerged as the first application of gps to
cross over to civilian use. While there were too few satellites in orbit in the
early 1980s for practical navigational use, surveyors did not require real-time
calculations. They could record observations using signals whenever the sat-
ellites passed overhead and process the data later. gps saved time and boosted
productivity so much that it cost about 10-20 percent of the cost of conven-
tional surveying while offering accuracy three times that of existing methods. 43
The National Oceanic and Atmospheric Administration (noaa), which is part
of the Department of Commerce and oversees the National Geodetic Survey,
published the first technical standards for civil gps use in the Federal Register
in 1984. This step helped convince the surveying industry that gps signals—
generated by a military system—would be available for commercial use. 44
Surveyors for years had been using inertial surveying systems (iss), which
employed gyroscopes and the same principles as the ins systems used on air-
liners, as well as Doppler systems that relied on radio signals from Transit (the
Naval Navigation Satellite System, or nnss). This use of Transit traces its lin-
eage directly back to the Vanguard satellite proposal, which envisioned the use
of satellites for geodetic purposes. The earliest gps receivers, designed in the
1970s to test the fledgling fleet, were built under defense contracts, but elec-
tronics manufacturers already had been building survey instruments using
radio signals. As the gps constellation grew, it was natural for some to see a
new market for surveying use. The first commercial gps receivers appeared
around 1982, including the sti-5010, built by Stanford Technologies (similar
to those developed for the military's gps ground tracking stations); the Mac-
rometer v-1000, designed by Massachusetts Institute of Technology research-
ers and marketed by Litton Aero Service; and the Texas Instruments ti 4100,
known as the “navstar Navigator.” 45
At the time, six of twelve satellites planned for the first block of the gps con-