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iphone question: isn't GPS redundant?

post #1 of 5
6/6/07 at 3:16pm
Thread Starter 
so here's my iphone related question....

cellular technology basically triangulates your position relative to the known locations of cellphone towers. this information is used to determine which tower will handle your signal as you move from place to place. this means your position is known to the network.

instead of using a battery-hungry and slow GPS transponder to get info on your position from an orbiting satellite, wouldn't it be easier and quicker to get it from the cellphone tower itself? think about it. no extra battery drain. no uplink/downlink delay and you get navigation anyplace you can get a cellular signal.

all you'd need is cooperation between a device and the network...that and some additional bandwidth for handling the round trip query....precisely the kind of bandwidth AT&T has been adding lately to supposedly boost EDGE data rates.

is there a connection or am i mistaken about how all this works?
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"Mac users enjoy a love-hate relationship with Microsoft--in which love is defined as "resigned tolerance" and hate as "lava-hot rancor fueled by the fire of a thousand burning suns."

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post #2 of 5
6/6/07 at 3:32pm
Right now a lot of the cell phones do this. Its not as accurate as a real GPS, but its close enough that it works.
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post #3 of 5
6/6/07 at 3:35pm
There are many advantages to GPS over tower triangulation. Tower triangulation takes at least three, and preferably four towers. It's not as precise and it won't work in as many areas. It will place in you in the "area" (to within the mile or within a few blocks, depending on the number of towers and the signal strength), but you can forget about having tower triangulation guide you down the street precisely and give you turn-by-turn directions.

That said, if iPhone uses it, it will probably work well enough to show you the nearest restaurant. I'm fine with that level of service. But you're incurring the wrath of GPS fans by comparing tower triangulation to GPS....
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post #4 of 5
6/6/07 at 5:18pm
The best solution is GPS and tower triangulation. The more data sources, the quicker and more accurate the fix is. Urban conditions are far from great for pure GPS usage. A system with both can even triangulate more accurately because it can use the GPS to learn the average errors of the tower triangulation and apply that knowledge when GPS fix is not up.
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post #5 of 5
6/6/07 at 8:18pm
Thread Starter 
Quote:
Originally Posted by nevenmrgan View Post

There are many advantages to GPS over tower triangulation. Tower triangulation takes at least three, and preferably four towers. It's not as precise and it won't work in as many areas. It will place in you in the "area" (to within the mile or within a few blocks, depending on the number of towers and the signal strength), but you can forget about having tower triangulation guide you down the street precisely and give you turn-by-turn directions.

That said, if iPhone uses it, it will probably work well enough to show you the nearest restaurant. I'm fine with that level of service. But you're incurring the wrath of GPS fans by comparing tower triangulation to GPS....

i never meant to incur the wrath of anyone...just wondering out loud.
"Mac users enjoy a love-hate relationship with Microsoft--in which love is defined as "resigned tolerance" and hate as "lava-hot rancor fueled by the fire of a thousand burning suns."

-Macworld
Reply
"Mac users enjoy a love-hate relationship with Microsoft--in which love is defined as "resigned tolerance" and hate as "lava-hot rancor fueled by the fire of a thousand burning suns."

-Macworld
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