New GPS Satellites Accurate to Within Three Feet
Lockheed-Martin is testing a new-and-improved Global Positioning System satellite as part of a $5.5 billion upgrade. The satellites should be in orbit in 2014, with the first launches in 2013.
The new generation of satellite will be more accurate than the old one, able to track positions within three feet, whereas the current satellites can manage 10 feet. They will also be able to get a better fix on people who are indoors or under forest canopies.
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Lockheed-Martin won’t say much about exactly how it has improved the system, though it has published a fact sheet. A company spokesperson told Discovery News that the technology is “sensitive.”
That said, there are a few technical advances that can be noted.
– Reflectors. The new satellites will have reflectors that will be used by ground crew, who will fire a laser beam at the craft to determine how far off the satellite is from its position. The laser reflectors reduce the need to depend on the satellite's radio signals. The checks will also reveal whether the satellite’s clock is off; and if so, corrected to make global positioning more accurate.
– M Code. The satellites will emit a new military signal, called M-code, which is more difficult to jam and offers better security. The signal will be sent from a high-gain antenna that also provides a spot beam designed to boost the signal strength.
– Civilian Signal. Along with the military signal, each satellite will send a civilian signal. Sending two signals (military and civilian) to GPS devices will allow for better error correction.
Stronger, more accurate signals will benefit everyone. Google will be better able to move its mapping function indoors, and hikers with GPS devices will have an easier time not getting lost.
Via Associated Press
Image: Wikimedia Commons / NASA