Using GPS data in Application

I want using GPS data (I got it from $GPRMC) in an desktop application(that uses from mappoint 2009). I get the latitude & longitude, but when I check these points on map, I see the result is incorrect (for example My Data is: 43.412 N, 79.369 W ; but the correct point is: 43.686开发者_JS百科 N, 79.616 W ). I guess, I must use a correction method before use; I try "Projection method" like "Miller" or "Mercator", but those aren't effective. Can anyone guide me?

Are you using the same coordinate systems? E.g. WGS-84 or something else?