I have updated the Android program GPS Prasna so that it now listens for GPS location updates while running.  Thanks to rather lacking documentation by Google I originally thought the implementation I had was sufficient but later learned that the program needed to have a "location listener" implemented to work properly.   Now it works flawlessly as I can attest using my Android phone.  When GPS is available and turned on you'll see the satellite dish icon in the Android top bar as shown here.  With this free software you can get a prasna chart with the correct ascendant for your present location.  Try that on an iPhone.

GPS Prasna is available for free on the JyotishTools.com web site on the Android page or on the Android Market.