If you're piloting a crazy homebrew quadracopter, sooner or later you're going to want to be able to pilot your UAV beyond where you can see it. And for more precise tracking, your ordinary GPS receiver's five-meter accuracy just ain't gonna cut it. A couple of enterprising engineers have successfully Kickstarted a new receiver called the Piksi, which they claim is accurate down to just a few centimeters.
GPS is a pretty remarkable technology, but there are a number of limitations to the way your position is calculated. First of all, the bit length of a GPS code is about 300 meters, which means that even with signal from four satellites your position can only be calculated to within a few meters—at best. Furthermore, the ionosphere introduces delay into the signal, which increases error.
The Piksi mitigates these problems and improves accuracy and precision in two ways. In addition to measuring the GPS code beamed down by satellites, it also measures the phase of the 19 centimeter wavelength of signal the code is carried on. Using a little algorithmic processing, the Piksi can use this information to improve location accuracy. Furthermore, the Piksi system uses an additional receiver as a reference point to help mitigate the effect of the ionospheric delay.
The project has already been fully funded, but you can still pick up a good deal on the Piksi. Individual units during the Kickstarter campaign cost $500, compared to the expected $900 price once the product goes into production. Usual Kickstarter caveats apply. Buy at your own risk.
This unit sure isn't cheap by traditional standards, but considering a comparable product for professional applications usually costs many thousands of dollars, it's relatively reasonable. Plus, if you're flying a couple of grand worth of drone up in the air, it's probably worth knowing EXACTLY where your money is flying—lest all that cash fly away. [Kickstarter via Engadget]