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LocataLite  (Source: gmat.unsw.edu.au)
"LocataLites" are ground-based versions of GPS satellites that are the size of a hardcover book

Global Positioning System (GPS) technology has made its way into most of our lives either through social networking (when you check in somewhere on your Facebook) or when driving a vehicle. Current GPS tech uses satellites to pinpoint a device's location, but Australian company Locata has developed ground-based location technology that is more accurate.

Locata's new system consists of devices called "LocataLites," which are ground-based versions of GPS satellites that are the size of a hardcover book. LocataLites will be installed locally in several locations, sending out signals using the same frequency as Wi-Fi that receivers utilize to calculate an accurate location. These signals can cover several kilometers, and since LocataLites placed in the ground as opposed to tens of thousands of miles into space like traditional GPS trackers, it takes less time for LocataLites' signals to reach receivers.

While traditional GPS devices pinpoint a device's location accurate to a few meters, LocataLites will pinpoint a location accurate to a few centimeters. This sort of accurate positioning could have many benefits, such as enhancing cell phone apps and keeping track of goods and machines at construction sites and other businesses. In fact, the technology has already been promised to the U.S. Air Force, which will use the LocataLites to track aircraft on the Air Force's White Sands Missile Range in New Mexico. Also, the LocataLites are already in use at the Boddington gold mine in Western Australia to position digging and drilling equipment.

In addition to accuracy-related benefits, Locata's new ground-based GPS tech also has cost-related advantages. Traditional GPS satellites use expensive atomic clocks to "timestamp" the signal it sends back to Earth, and receivers use that timestamp to calculate the distance from a satellite based on the time it took to get there. LocataLites do not have these pricey atomic clocks, but rather a cheaper timing chip coupled with Wi-Fi technologies that are simpler to deploy.

Locata plans to release more information next month that will allow other companies to manufacture receivers.

"It's like the early days of GPS," said Nunzio Gambale, one of Locata's co-founders. "The real explosion will happen when there are chip-scale receivers that can fit into your pocket."



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RE: Location Location Location
By Warwulf on 8/3/2011 7:53:55 AM , Rating: 2
I call shenanigans!

In order to be able to use the 2.4 GHz unlicensed band, I don't think the transmitter can have more than 1W ERP. You're looking at a coverage area of MAYBE a square kilometer... but not several. Not to mention, if you're timing the difference between closer stations, don't you need MORE accurate internal clocks as nano second timing now makes more of a difference?

Great, just what we need... another 2.4 GHz spectrum device... as if things weren't already overcrowdedd with cordless phones, wireless mics, wireless cameras, baby monitors, etc. We do not need this added congestion.

Plus, I don't see this system being deployed in rural areas.


RE: Location Location Location
By MozeeToby on 8/3/2011 11:07:45 AM , Rating: 2
Check out Shannon's Law: http://en.wikipedia.org/wiki/Shannon%E2%80%93Hartl...

Basically, even a low power transmitter send data over a congested frequency, the limit is in how much data can be sent. In this case, they could have a useful system successfully delivering 64 bits of data once ever 10 seconds. That is a tiny fraction of a percent of what you can deliver at higher signal strength, but is enough for their system.

As for the clocks, I think you would need more accuracy, but the overall system can be simpler. For example, you don't need to take general and special relativity into account if all your stations are in the same reference frame and approximately the same altitude as your receiver. More obviously, you don't need to power and maintain the transmitters in orbit.

I can hardly say I like the idea of a device blasting away at the maximum allowable power on the WiFi bands, but from a technical standpoint there's no reason that it can't be done (especially considering that similar systems are in place at airports around the world for assisted landings).


RE: Location Location Location
By Fritzr on 8/4/2011 9:13:05 PM , Rating: 2
The problem with widely spaced pulses is that you lose the time advantage over satellite GPS. One of the mentioned selling points is speed. Even a 1 second pulse rate allows the satellites to give a faster response.

Yes they can be accurate, but lets give the device a 5K range from the transmitter (10K diameter circles & 10K vertical directly above the transmitter) and ignore shielding effects. A minimum of two signals is needed for triangulation, 3 or more give greater accuracy. How do they plan to provide the worldwide coverage, including the oceans, arctic and antarctic ice sheets and hostile nations? Even with a plan for positioning transmitters, think of the massive deployment that is required to provide the service that satellite already offers.

There are applications where this tech makes sense. Fully automated landing for aircraft & automated vehicles on freeways and similar restricted access roadways are two that come to mind.

For localized usage, the tech is already available and does not require WiFi frequencies. In fact for some applications WiFi and other bands where interference can be expected will cause problems with GPS autopilot/autodriver when using this tech.


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