One System, Two Narratives - GPS Declassified: From Smart Bombs to Smartphones - page 55

by a single atomic bomb in space and the European constellation would have
been denounced by the Soviets as a spy platform . 7 Even if the 621b satellites
had atomic clocks, the system was more vulnerable than Timation since only
ground stations in the same area could update the satellite clocks in synchro-
nous orbits.
Roger Easton, in his eascon paper “Mid-Altitude Navigation Satellites,”
stated, “After considering both lower and higher altitudes the mid-altitude
(approximately one earth's diameter) polar circular satellite constellation has
been selected as a prime possibility for an accurate, all weather, always avail-
able, three dimension, U.S. based navigation system.” Later in the paper he
stated, “The minimum number of satellites necessary to have three visible
[from] anywhere on the earth's surface is approximately twelve.” He then
added that more satellites were desirable since while having three in sight is
enough for navigation, a fourth is occasionally required to correct the receiv-
er's clock.
Air Force Space Command senior historian Rick Sturdevant has written,
“As early as 1969-1970, Aerospace Corporation president and gps pioneer
Ivan Getting had suggested to Lee DuBridge, President Richard Nixon's sci-
ence advisor, that a presidential commission be created to review how satel-
lite navigation ought to proceed, because there were so many potential users.
After thinking about it for several weeks, DuBridge concluded that execution
of Getting's proposal would be too difficult. He told Getting, 'there are too
many people, too many bureaucracies, too much politics, and too many agen-
cies involved. Why don't you just have the Air Force develop it the way we
always did?'” 8
Sonnemann comments, “It was our responsibility to arrive at a consensus
with regard to the elements of the system, including the orbits of the satellites,
the signal structure best suited for the project etc., etc., as well as management
issues.” 9 This was challenging due to the different objectives of the services.
The Air Force focused on precision targeting of munitions, whereas the Navy
needed worldwide navigation for its ships, including missile submarines near
the North Pole, and for airplanes based on aircraft carriers.
nrl's Ron Beard, who was the second successor to Easton as branch head,
has written that “from 1968 through 1970 the Timation concept grew from a
Category 6.2 exploratory development project into navigation satellite tech-
niques to a Category 6.3 development system concept.” 10 One requirement for
a Category 6.3 program was writing a development plan. Consequently, the