The .zip file files need to be uncompressed before use.
You have to use Winzip software to uncompress. If you don't already have it installed, it can be downloaded
for free from http://www.winzip.com.
Once uncompressed, you'll have the database files ready for use (file extension .ng2). Then follow the instructions
below on how to install it on your system for use by Navgps.
Note for USA Navgps Basic Users: The USA databases above are a composite of FAA and DAFIF data sources.
The airports available may be different than what was there before the merging of the two databases.
If you'd rather use the DAFIF databases, then you can still download the old sample files
from these links - USA-east and USA-west.