-What is GPS? The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense.
-Is it free?
Yes, GPS signals are free, you just need a GPS receiver device and maps. There is no subscription fee of GPS signals. To better understand this you can compare this with your FM radio receiver and FM signals transmitted from FM stations.
-Why some GPS Service providers charge?
These service providers charge you for GPS application, maps, map updates, and add on services like traffic updates, weather updates.
Some charges are one time and some are recurring. Charges for device, GPS application and maps are one time. And if you subscribe for weather, traffic update services then you have to subscription charges. (may be annual or monthly)
-Where can I get free maps?
Yes, you can use google maps, yahoo maps, openstreet maps, MSN maps…. lots more options. But these maps are downloaded over GPRS or 3g, so your mobile service provider will charge for download.
-How can I avoid download cost?
You can use stored maps. This too depends on application you are using. You can buy maps from GPS service providers (like satguide.in, mapmyindia.com etc in India)
Or use tools to download map tiles from google maps, yahoo maps etc (for eg http://www.mgmaps.com/cache/ )
-Can I get free GPS applications?
Yes, there are many free GPS applications, like google map application (www.google.com/gmm) , MGmaps (www.mgmaps.com) and so on.
-Can I use GPS in mobile phone?
Yes, if you have inbuilt GPS in your mobile then you can simply install any free or commercial GPS application and use it
If you don’t have inbuilt GPS in mobile phone then you have to buy a GPS Bluetooth module and couple it with your mobile phone and install any free or commercial GPS application. Read this http://www.mka.in/index.php?/archives/19-Altina-GBT709-Bluetooth-GPS-receiver.html
-GPS works everywhere?
Depends on GPS signal strength (number of satellites) and quality of GPS receiver. Normally it is hard to get signals in indoors.
Many times if you switch on GPS in moving vehicle it takes too long (may be 20-30 minutes) to lock satellite signals, So its recommended to switch on GPS in stationary position and wait till receiver is able to see some satellites.
-How accurate is my position?
This depends on GPS signal strength and quality of GPS receiver. Normally this its within 25m and in good signal conditions its close to 5m.
-Can I share my location with friends and family?
It depends on application you are using, you can publish you location using MGmaps and make public/private on www.gmap-track.com. Or you can use google map application with google latitude to publish location and use API to publish location on your blog (http://www.google.com/latitude/apps)