A-GPS on 3G iPhone
When I first read that the 3G iPhone was a GPS receiver I was very excited. In fact that was the moment that I decided to buy my own 3G iPhone.
I have researched and written quite a bit about GPS technology and the standalone devices available on the market today. Any device that performs multiple tasks will very seldom be as great as one that function one task well. So, I am not put off by the GPS features not found on the 3G iPhone. After all, I will still have live traffic information, keyword searches for Points of Interests (POI), a list of turn by turn directions and a route that is highlighted with GPS tracking.
Assisted GPS or A-GPS is what the 3G iPhone uses. If you are like me this type of GPS is unfamiliar. So what is it exactly and how does it work?
Most everyone knows by this date in time what GPS is. A Global Positioning System is understood to work with the free satellites orbiting high above the earth. GPS requires a receiver in order to receive those signals. Generally a clear view of the sky is necessary for these signals to be picked up and translated.
Assisted GPS or A-GPS is a bit different. It is actually faster at pinpointing your location because it uses a variety of technologies to deliver its information including an Assistant Server. An Assistant Server saves both time and energy so the cell phone GPS can be fast and energy efficient. Since the cell phone (GPS receiver) does not have to calculate as much information battery power is preserved. The 3G iPhone is quick to turn the GPS feature on and off in order to save as much battery juice as possible.
Not only are signals from Satellites used but signals from WiFi locations and cell towers are used as well. Positioning via WiFi and cell towers does not require a clear line of sight to the Satellites. Depending on which signal is available to the iPhone 3G is the one that will be utilized.
The 3G iPhone uses built in maps as well as other mapping applications that can be downloaded from the App Store. When GPS is employed a circle will surround your location. The more accurate the signal the small the circle will be.
The 3G iPhone is not the only device that uses Assisted GPS. In fact Navizon sells the software that makes Assisted GPS work on your device. Since the software is already loaded onto the 3G iPhone for free it is another example of the benefit received.
Assisted GPS built into cell phones is quickly becoming a great help to emergency support personnel. E911 is the cell phone equivalent to 911 on a land line. Quicker response times saves lives and now our cell phone can assist them in finding us when we are away from a land line. We can be located whether inside a building, in a big city full of tall buildings or even inside of a moving car.