iPhone's GPS accuracy in the woods

[moonman239]

I'm developing a Webapp that will estimate how wide a river is. What would happen is the user would load the app, then wait until the app decides its location fix is good enough. Currently, that means that the phone estimates that the user is no more than 55 feet away from his or her estimated location. My question is, how much accuracy can I really expect without having the user wait too long?

 

[Mrg02d]

Depends on the GPS chip,no? At work, our service guys have gps units that are accurate to under a foot.

 

[MuddyPaws1]

Accurate to 55 feet isn't all that accurate at all.

 

[takeshi74]

http://www.gps.gov/systems/gps/performance/accuracy/

55 feet is well above what you can expect from GPS.

Accurate to 55 feet isn't all that accurate at all.

It's all relative. Consider the accuracy of tower triangulation which easily goes up to 2000m (depending on conditions) in my experience.

 

[ThatsMeRight]

http://www.gps.gov/systems/gps/performance/accuracy/

55 feet is well above what you can expect from GPS.


It's all relative. Consider the accuracy of tower triangulation which easily goes up to 2000m in my experience.

GLONASS is also used (Russian variant of GPS), so accuracy should be much higher.

 

[old-wiz]

Usually consumer grade GPS devices are accurate to no more than 3 meters, and then only in optimum conditions.

 

[moonman239]

Is there anyone out there who has taken a 4s or a 5 away from civilization and used the GPS feature?

 

[avanpelt]

Is there anyone out there who has taken a 4s or a 5 away from civilization and used the GPS feature?

I haven't, but I assume you could simulate this by turning the cellular radio off. The GPS chip still functions with the cellular radio turned off on a newer iPhone, correct?

 

[moonman239]

I haven't, but I assume you could simulate this by turning the cellular radio off. The GPS chip still functions with the cellular radio turned off on a newer iPhone, correct?

I've heard you can, but I have not personally verified that statement. I never actually used location services while away from a cell tower or WiFi hotspot.

Edit: I just turned on airplane mode and attempted to get Maps to show me where I am, but the app told me to go to Settings and turn off airplane mode.