I am an engineering undergraduate student. I am currently working on a project to implement a sensing package on a quadcopter for the deployment in the canopy of tropical rain forests. This package needs to measure temperature, humidity, pressure and light intensity. All these have been taken care of, but it also needs to precisely obtain the position of the quadcopter and I am not sure how to achieve this. As it will operate in a rain forest, a standard GPS will probably not be accurate enough in part due to the bad signal (forest means a lot of trees and vegetation around). I am building everything on an Arduino Mega 2560 board. I was thinking on using D-GPS but I am not sure how to implement it.
Does someone know how I could obtain a precise (submeter precise) position of the quadcopter?