Going Mainstream - GPS Declassified: From Smart Bombs to Smartphones - page 140

Public safety organizations urged the Federal Communications Commis-
sion to require that wireless providers install technology to identify the loca-
tion of a mobile 911 caller. They worried that increasing cell phone use would
render call-center infrastructure obsolete, putting lives and property at greater
risk. Wireless industry groups questioned the technical feasibility and called
mandates and compliance dates “undue burdens” that would hurt their indus-
try and the economy. 133 Estimates of the cost to implement the enhanced 911,
or e-911, requirements ranged from $550 million to $7 billion. 134 In June 1996,
after forging an agreement between public safety organizations and the Cel-
lular Telecommunications Industry Association (ctia), the fcc gave all wire-
less carriers one year to begin transmitting out-of-network 911 calls and a year
and a half to provide 911 dispatchers with the wireless caller's phone number
and nearest cell tower. 135 Within five years wireless carriers were required to
develop ways to give emergency operators the caller's location within a roughly
four-hundred-foot radius at least two-thirds of the time. 136 To cover upgrades
at local 911 call centers, most states levied taxes—the familiar e- 911 surcharge
that appears on phone bills.
Two main alternatives emerged for complying with the e-911 mandate; both
were early-stage technologies far from being ready to deploy. One method,
known as radio triangulation, calculated a caller's position based on the slightly
different times the phone's signal arrived at three network antennas. The other
approach required adding gps receivers to individual handsets. The triangu-
lation method concentrated costs on the network infrastructure, while the gps
solution shifted most of the costs to the handset. 137 Triangulation worked bet-
ter in “urban canyons,” where tall buildings block gps signals; gps worked
better in rural areas with fewer cellular antennas. However, gps posed an addi-
tional drain on the phone's battery and required more time to phase new phones
into the subscriber base. 138
By this point gps receivers had been shrunk to postage-stamp-size integrated
circuits—silicon chipsets combining radio frequency receiver functions and
central processing units for gps signals. gps chipmakers embraced the e- 911
mandate as an opportunity to sell their technology to phone manufacturers.
SiRF Technology Holdings, founded in 1995 by a former Intel executive and
based in Santa Clara, California, announced soon after the fcc decision that
it had developed advanced gps chipsets that could more quickly acquire even
weak satellite signals while filtering out error-causing multipath (reflected)
signals. 139 SiRF turned its attention to reducing power consumption and within