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China to Deploy Secure GPS by 2010
hackingbear writes "Unsatisfied by the reliance on American GPS navigation systems and not feeling much security joining the European Galileo system, China will expand its 4-satellite Beidou navigation system to a full-fledged, competitive, and encrypted system by 2010."
Silly me forgot the link........ http://www.space.com/news/070202_china_spacedebris.html
GPS is one way communication, it does not send anything back to the satellites. To do so would require either a very powerful transmitter on the ground device (say goodbye to GPS in your mobile and other handheld battery powered devices), or a very sensitive receiver on the satellite with the signal processing power to differentiate the weak signals of millions of devices from each other and from the general radio noise coming from earth.
WAAS - wide area augmentation system begain deploying a few years back. It has 25 ground sations in the US that recieve the signal and then send corrected signals back up to the satellite.
The next one, is called LAAS, local area augmentations system, like the WAAS but much more local. It is designed specifically for aviation and is only good in a 20 mile proximity to the airport. It's supposed to be a cheaper replacement for ILS systems.
Take a look on wikipedia under WAAS GPS & LAAS GPS there are some pretty decent articles on them.
You wouldn't really need any changes to the GPS for that- the satellite has no knowledge about the position of anyone receiving its signal anyway; the positioning signal is one way. In theory, a receiver could of course send an ID and the location it computed from multiple satellites back to one of them- but you'd hardly use the GPS satellites for tracking millions of individual devices. Much more likely, it would work somewhat like the EU's Galileo extension to the COSPAS-SARSAT system.
But, constantly and silently tracking the location of millions of GPS receivers is - luckily - science fiction as of today.
Plus, there would be no way of enforcing this - anyone building a Compass receiver could simply ignore the demand for a transmitter/tracker, unless the Chinese released no specs and managed to keep their system completely secret, but this would of course conflict with the availability of a 'public' signal.
A much more unpleasant thought is that, even today, your current position can be determined at any given time, albeit with low accuracy (couple of 100m in cities), if you walk around with a connected cellphone in your pocket.
"China is now gearing up faster in the military front faster than anybody has over the last 100 years. That includes Hitler's build up in 1934-46, and FDR's 2 year build-up"
Huh? In the mid 1930's Germany was producing hundreds of attack subs a year, hundreds of aircraft a year and thousands of tanks! Unless China has hundreds of secret military factories, they are not even coming close to matching Nazi Germany's militarism.
If you consider how old most of China's current military hardware is (nearly all their current navy is from the Cold War era), it's not particularly surprising they are using their new-found wealth to upgrade some very old kit.
I see the glass as full with a FoS of 2.
Nope. The US system has selective availability turned off, and all new US GPS satellites don't even have SA functionality, so they can't turn it back on later.