Cellphone tracking: New devices can calculate your altitude.
Cellphone tracking: Find an address? Easy. But new
devices can calculate your altitude.
New devices are able to determine not only what building
you and your phone are in but also which floor you’re on. (Bigstock)
By Craig Timberg November 19 at 9:00 PM
Cellphones long have doubled as tracking devices, capable
of revealing your location to police, paramedics, even grocery stores looking
to deliver coupons to nearby customers. But there’s a measurement cellphones
once struggled to make: altitude.
No more.
Cellphone tracking is about to go vertical as the
location-services industry, prodded by the U.S. government, solves the riddle
of what experts call “the z vector.” Soon it will be possible to determine not
only what building you and your phone are in but also whether you are on the
first or 15th floor.
One key is the rapid spread of barometric-pressure
sensors, which have become standard features in Apple’s iPhone 6 and several
Android devices. More than 100 million of these smartphones already are in the
hands of consumers, capable of making air-pressure readings that can be used to
estimate a user’s altitude, to within a few feet.
The systems, though now used mainly for apps that users
control, are part of a new generation of location technology that could collect
altitude data from smartphones and use it to, for example, help rescue crews
find people trapped in an office-tower fire. But privacy advocates warn that
detectives, intelligence agencies and maybe hackers could gain the ability to
map the three-dimensional movements of cellphone users with startling new
detail.
Sensors in smartphones that measure air pressure can now
determine the callers’s altitude.
An early glimpse at this tension is playing out at the
Federal Communications Commission, which is updating its requirements for how
wireless carriers handle 911 calls, 70 percent of which now come from
cellphones rather than land lines. In a proposal that could be adopted as soon
as January, the FCC would require wireless carriers to build more-precise
location systems capable of finding callers anywhere, even in a multistory
building.
The proposal has triggered a lobbying fight, with some
public-safety groups supporting strict FCC rules and wireless carriers pushing
for slower implementation and different technology. The outcome of that
struggle is likely to determine the precision of the next generation of
cellphone tracking and how quickly it arrives.
“This puts those of us in the civil-liberties community
in a difficult position of opposing the creation of location services for
emergency services, because we know the FBI will ask for it later and we don’t
have the power to stop them when they ask for it later,” said Christopher
Soghoian, principal technologist for the American Civil Liberties Union.
The FBI declined to comment on the location rules under
consideration by the FCC, but the bureau’s own investigative guidelines say it
can seek access to any information supplied to other government agencies.
Previous generations of FCC location rules, though created for 911 services,
eventually led to the FBI quietly gaining an expanded ability to track
cellphone users.
The potential goes far beyond government uses, said
Manlio Allegra, chief executive of Polaris Wireless, one of the
location-services companies experimenting with altitude measurements. Malls
could use altitude tracking to monitor crowd flows and send coupons to the
phones of customers walking past a shoe shop on the top floor. Multilevel
casinos could monitor gamblers for security purposes. Companies could better
keep tabs on the movements of their employees, especially those handling
expensive products.
“It’s like a tidal wave,” Allegra said of the potential
for three-dimensional tracking. “You upgrade the network, every performance [capability]
on the network gets upgraded.”
From air to ‘z’
The technology works on a simple principle: Air molecules
concentrate more densely at low altitudes than at high ones, causing measurable
variations that follow predictable patterns. Even if overall barometric
pressure at a certain location is shifting — say, as a hurricane approaches —
the bottom floor of an office building will have higher pressure than the top
one.
The air-pressure sensors built into the latest
smartphones have sparked the development of a range of apps. Some help forecast
the arrival of storms; others claim to alert anglers to when fish — which are
said to prefer high, stable pressure — are biting.
The iPhone 6 includes a health app that uses changes in
air pressure to estimate how many stairs a user climbs each day. Apps that help
hikers navigate peaks and glider pilots track flights are increasingly using
barometric sensors to measure altitude, something that GPS tracking technology
struggles to do as quickly and accurately.
Australian glider pilot Peter Rundle built an Android app
called GlideMate that maps longitude and latitude — the “x” and “y” vectors —
while also showing the “z” vector of altitude based on air-pressure readings
made by the smartphone.
GlideMate also tracks rates of ascent or descent,
mimicking a device called a variometer and allowing him to leave some bulky
gear behind when he flies. “It’s easier to just have one instrument that does
everything,” Rundle said.
The Polaris Wireless altitude sensors work roughly the
same way. During a demonstration for government officials on the seventh floor
of FCC headquarters in September, amid the cluster of drab office buildings
south of the Mall in Washington, a company employee carried a Samsung Galaxy S3
smartphone down several flights of stairs, said Allegra, the Polaris CEO.
Using software the company designed, the Samsung device
measured the pressure shifts and relayed them to a server at the company’s
Silicon Valley headquarters. The server then compared the readings with an
atmospheric model of the area and reported the shifting altitude estimates to
another device, as Allegra and the FCC officials looked on.
The proposed FCC rules would not endorse a particular
location technology, but any new standards are likely to spur innovation as
companies compete for the lucrative business of helping wireless carriers
comply.
“We are committed to both improving public safety and
protecting consumer privacy,” David Simpson, chief of the FCC’s public-safety
and homeland-security bureau, said in a statement. “The goal of this proceeding
is to use technological advancements in the marketplace to help first
responders better locate 911 callers. We’ve sought public comment on our
proposals, including any privacy implications, and will consider all input as
we move forward.”
The four largest wireless carriers reached an agreement
with two major public-safety groups last week, endorsing standards and a
timetable less stringent than proposed by the FCC and relying on a different
technology — using maps of WiFi and Bluetooth signals, as some commercial
location services now do — for determining the address and altitude of a 911 caller.
Other groups are still pushing for air-pressure
technology, arguing that it is more reliable and precise and could be
implemented more quickly. “The [wireless] industry is basically trying to slow
the train down,” said Harold Schaitberger, general president of the
International Association of Fire Fighters. “That’s very troubling to us.”
Beyond GPS
A 911 call is unlike any other: A person dialing the
number typically is seeking help from authorities to report a crime, fire or
medical emergency. The dispatcher needs to know the location of the caller to
direct the appropriate responders to the right place, even if the caller cannot
or will not provide that information.
Several technologies, operating under existing FCC rules,
already are capable of finding 911 callers based on data that flows through
cellular networks, such as what cell towers phones are using and how quickly
signals are reaching them. Increasingly, though, carriers also are activating
the GPS chips in smartphones to determine the locations of callers and sending
the results to dispatchers.
Yet some in the location-services industry, backed by
coalitions of emergency workers, have argued that existing systems are flawed
and imprecise. GPS tracking, for example, needs a clear line of sight to
satellites, making them all but useless when somebody inside a building makes a
911 call.
“There needs to be privacy protections, but right now,
for all the networks, that’s not the challenge,” said Jamie Barnett, a former
top FCC official now lobbying for one of the location-services companies,
TruePosition, and also for a coalition of emergency workers that the company is
funding. “The question is, can the networks even find you?”
Many privacy advocates support the idea — in concept — of
better location tracking for 911 calls but fear government overreach. The last
time the FCC updated its location requirements for wireless carriers, several
later agreed to provide that same data to the FBI.
The increasing use of GPS tracking, the privacy advocates
say, offers a cautionary tale. Even if callers have turned off the capability
on their smartphones, 911 systems are capable of remotely activating GPS
functions and extracting precise locations.
This may cause little concern since somebody calling
authorities typically wants to be found. But if smartphones are designed to
include the ability to have their GPS tools activated remotely, there is no
guarantee that others will not secretly take advantage of that feature. Users
making 911 calls typically do not get notification that their smartphones have
activated the GPS functions and reported the location to authorities.
Jim Dempsey, senior counsel to the Center for Democracy
& Technology and a veteran of debates over FCC location rules, said privacy
concerns could be lessened by requiring wireless carriers to build systems
capable of transmitting altitude measurements only during 911 calls. “It’s not
like the FCC is forcing anyone to design a mass surveillance tool of the
future,” Dempsey said.
But Rundle, the Australian glider pilot and app
developer, said location data generated for 911 calls will inevitably be
collected by the government — and perhaps others — to track cellphone users.
“It’s the dilemma of today’s technology. You can’t make
it hack-proof,” he said. “If somebody can program it, someone else can
re-purpose it.”
Brian Fung contributed to this report.
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