GPS receiver is a hardware which is normally available in most smartphones. This receiver can fetch the location data from satellite FREE of cost. But this data is in raw form and you need an application (like Google Maps) which can actually process this data for you and show you the directions on a map.
Remember, GPS receiver does not help you with maps on its own. A map generally contains all the places embedded in it along with latitude and longitude information.
Once you download and install the maps and the application, you donít need an internet connection on mobile i.e. no data charges would apply at the time of searching for locations while travelling.
This essentially means that if you do Not download the maps initially and try to use the GPS application to find directions while travelling, the application will try to download the maps on the fly and this will definitely need an active internet connection and hence the data charges on your mobile phone would apply.
Your location changes quite frequently while travelling pushing the GPS navigation application to download quite a number of maps and would consume good amount of data.
Google maps application is FREE to use but unfortunately they do not allow downloading of their maps.
Hence, you canít access them offline or without internet as of now.
So, if you actually use Google maps to find directions using your own FREE GPS receiver (installed in your smartphone), it would still need your mobile internet connection to download maps on the go and show you directions.
So, even though you have a GPS receiver in your phone and GPS reception is FREE around the globe, you would still need to download and install the maps and the user application that helps you use the GPS information for navigation. There are many companies which provide maps and the navigation application free of costs and can be found on internet or Anroid and iPhone app stores.
The other alternative could be to pay a one time fee for downloading maps and application from a company like Garmin and then use them without using your phoneís internet connection. But remember that you may have to pay for downloading updated maps and application in future.