I was just thinking...
Has anyone looking into real-time correcting the LEA-6 (or other DIY Drones GPS) using RTCM via Internet Protocol (NTRIP). I'm assuming you would just need to have a cellular modem (or phone) on the copter connected to the internet, receiving the RTCM data and passing it along to the GPS unit. I checked the U-Blox website and it says the LEA-6 has an interface for the RTCM protocol (http://www.u-blox.com/images/downloads/Product_Docs/LEA-6N_ProductSummary_%28GPS.G6-HW-11038%29.pdf). Many state's now offer a real-time GNSS network via NTRIP, some are free subscriptions while others are paid subscriptions.
I'm not a programmer so I'm unsure what it would require on that end to make it work.
Here is some example code I found for .NET (http://www.sharpgis.net/post/2005/01/21/Differential-GPS-using-RTCM-from-NTRIP.aspx)