One System, Two Narratives - GPS Declassified: From Smart Bombs to Smartphones - page 63

It is important to note that the Timation Development Plan specified using
both sidetone (or continuous wave) signals and spread-spectrum signals (see
chapter 5). This report was submitted on November 25, 1970. Thus the Timation
Development Plan proposed using a spread-spectrum signal two years before
Colonel Parkinson assumed leadership of Project 621b. This fact has been over-
looked in debates about the origin of gps. An August 6, 1971, memo from Air
Force lieutenant colonel Paul S. Deem states that a System 621b signal modula-
tor would be flown aboard Timation III (later launched as nts-1). This occurred;
thus there was cooperation between the Navy and Air Force long before the for-
mation of the joint program office. There has been so much emphasis on the
incorrect story that only the Air Force planned to use a spread-spectrum signal
that even some of the people involved in Timation have forgotten the plan's
intention to use both types of signals. Sonnemann, the former navseg chair-
man, commented, “Once the orbit decision was made, a navy 'victory' in the
eyes of the navy and the Air Force, the signal structure became the next hurdle.
The use of the pseudo-random sequence structure proposed by the Aerospace
Corporation for its 621b system had a number of attractive features, and no sig-
nificant detrimental characteristics that would suggest the Timation signal
structure should prevail. Adopting the 621b signal structure had the further
advantage of balancing the slate by giving the Air Force a 'victory.'” 27
Easton offered his assessment in a 1996 interview with Naval Research Lab-
oratory historian Dr. David K. van Keuren:
Dr. van Keuren: Parkinson agreed after these meetings to take the Timation
system and manage it [?]
Easton: Essentially.
Dr. van Keuren: Essentially. How much of the combined system was Air
Force and how much was Navy?
Easton: I say, “What percentage do you want to put on it?” You could say it
was ninety percent Navy and ten per cent Air Force, or you could use some
other thing, but it was the Timation system with a different modulation.
Essentially that is what it amounted to. That was in a way good because
it gave the Air Force something to say that, well, it was a combination of
two systems. The modulation, I thought, was the least essential thing
because it could have been pulses fm, am, sidetones, pseudo random
noise, all kinds of ways you could have done it. We used the sidetones,
and they worked, and we had hundreds of thousands of passes. . . . The