GPS augmentation options


I am looking at using the GPS on this board for tracking purposes but do not know the accuracy of the signal (I do not have the board yet, just looking at options).
Does anyone know if there is any augmentation used on the recieved signal, and if not, are there any possible ways of implementing augmentation (GDGPS, WAAS, EGNOS…) to help the accuracy?
Does the signal recieve any filtering at the input (e.g EKF)?
How can I find the GPS code to see if any post processing can be done on the signal?

thanks and regards,