It’s one of the most important technologiesof the 20th century.
如果明天它不工作了 银行会崩溃 飞机会迷路
If it failed tomorrow, banks would crash,planes would get lost
and you’d probably struggle to findyour way around the city
It’s called GPS and it was designed to defeat the Soviet Union.
This is how a Cold War technology went
from guiding bombs to guiding your Uber.
GPS is a network
of satellites which allows you to open your phone and know where you
are anywhere in the world.
Billions of people use it everyday.
But its roots can be traced back to the world’s first satellite.
“Today a new moon is in the sky. A 23 inchmetal sphere, place in orbit by a Russian
rocket” In October 1957 The Soviet Union launchedSputnik.
The Space Race between the USSR and America
had begun and the U.S. was losing.
“ All over the world people are tuning
in to the bleep bleep of the satellite, which carries
aboard the complex mechanism necessary totransmit secrets of the universe”
As the beach ball sized satellite flew above,
American scientists noticed that the radio
frequency it was transmitting increased as it approached and decreased as it moved away.
It’s called the Doppler Effect,
and it could be used to locate the satellite.
This was a Eureka moment.
If a satellitesposition was known, the position of a receiver
on earth could be determined
This is the basic idea of GPS.
In 1978, over twenty years after Sputnik,
the U.S.A. launched its first Navstar satellite.
This is the system we now call GPS.
“They will provide highly accurate and continuous global coverage
to authorised users by the late 1980’s”
Unlike earlier navigation satellites, Navstarwould give a constant positioning service
with unheard of accuracy.
Each satellite carried an atomic clock which broadcasts its location with a time stamp.
By using the location and time data from
at least four satellites, a GPS receiver can
tell you where you are,
并告知你的高度 速度 移动方向
your altitude and the speed and direction you’re moving in.
24 satellites are needed to cover the globe.
This was cutting edge technology,
run by the military, for the military
But that all changed when tragedy struck.
“My fellow Americans, I’m coming beforeyou tonight about the Korean Airline massacre”
On September 1, 1983,
a Russian fighter jet shot down a Korean Airline’s plane on its
way from New York to Seoul.
All 269 people onboard were killed.
The plane had deviated from its original route and flown through Soviet airspace.
Radio technology couldn’t track the planebecause of its limited range.
GPS would have solved this
Just two weeks after the attack,
President Reagan made GPS available for civilian use
as a common good.
But the U.S. military was concerned.
They didn’t want to give away
their latest space technology
The decision was made to restrict GPS’s accuracy
by purposefully messing with the
It would take another decade, several more GPS satellites,
and a war, for the technology
to develop into what we recognise now.
In August 1990,
the U.S. and it allies launched Operation Desert Storm to remove Iraqi forces
from neighbouring Kuwait.
This was GPS’s first full military test and it passed with flying colours.
It allowed troops to navigate and direct firewith unprecedented accuracy.
While cruise missiles were guided to theirexact locations
The Department of Defence paid million
to U.S. manufacturers to provide troops with GPS units.
After the war, manufacturers quickly found ways to market the new technology.
Then in 2000 GPS’s accuracy restrictionswere lifted
and the flood gates opened.
Since then the technology has become intertwinedwith our modern lives
GPS is the global time keeper.
Its atomicclocks are accurate to within 40 nano seconds
that’s four thousand-millionths of a second.
Banking systems rely on it to timestamp transactions, including withdrawing money from ATMs.
It is used to keep our trains running
on time and reduce farm wastage
Not to mention all the apps that rely on GPS.
Today the civilian satellite navigation market
is worth nearly thirty five billion dollars
And is expected to grow to more than eighty three billion by 2022.
Compare that with the global military
market and civilian uses now dwarfs it
It may have been born out of the Cold War,
but GPS services are now a critical part of
our everyday lives.