Where Are We? - GPS Declassified: From Smart Bombs to Smartphones - page 170

in 2010, Government Accounting Office Warns.” 175 The UK-based Guardian
Unlimited upped the ante with “gps System 'Close to Breakdown,'” and the
newspaper mX , in Melbourne, Australia, served up “Satnav Crisis: So Where
the Hell Are We?” 176 RusData DiaLine , a unit of Russia's Izvestia , penned the
optimistic headline “Russia's glonass to Profit from gps Problems.” 177 Such
headlines called to mind the breathless reporting of the Vanguard-Sputnik era
and the atmospherics that often accompany stories about technology man-
aged by the military.
The Air Force countered with a public relations offensive, including news
releases, interviews, the Air Force Space Command's first use of Twitter for a
two-way “tweet forum,” and an informational video on YouTube. 178 Col. Dave
Buckman, chief of Space Command's Positioning, Navigation and Timing Divi-
sion, tweeted, “gps will not go down.” 179 In the video Lt. Gen. John E. Hyten,
vice commander of Air Force Space Command, explained that thirty-four sat-
ellites were in orbit, two launches were scheduled in the coming year, and in
the worst year of gps's history (2000) no more than three older satellites
stopped working, providing an ample cushion above the twenty-four-satellite
threshold. “It's the healthiest constellation that we've ever had,” Hyten noted,
“and we are very confident that we'll be able to maintain that level of perfor-
mance in gps now and well into the next decade.” 180
Critics noted that despite the large number of orbiting satellites, each with
built-in redundancies such as multiple atomic clocks, many older ones were
down to “single thread” operation, meaning one more component failure could
leave a satellite unusable. 181 Widely reported signal problems with a satellite
launched in March, just two months before the gao uproar, made the Air Force's
public relations task more difficult. The satellite, svn 49, was the last of eight
iir(m) models, which introduced a second civilian signal (l2c). Engineers added
equipment to svn 49 to demonstrate and test the new l5 signal intended for
commercial aviation use that would be a standard feature of the iif series. That
change inadvertently affected the other signals, causing a permanent mul-
tipath (reflected) signal—a thirty-nanosecond echo—within the satellite itself. 182
The effects of the signal distortion varied with the angle of the satellite in the
sky and the type of receiver, complicating potential remedies for the prob-
lem. 183 At this writing svn 49 remains listed as “unusable.” 184
Such problems tended to attract more publicity than a significant advance
that occurred about the same time. The Naval Research Laboratory and a team
comprising mobile satellite service provider Iridium Satellite, Boeing, Rock-