I am trying to find accurate information on the refresh rate of the GPS on the iPhone 3G. I need to know how often the system updates your position, and how accurate it is (i.e. to within x feet). Are there any factors that affect the refresh rate or accuracy? Are there ways to control/improve the refresh rates/accuracy? etc.

I am working on an app that requires real time GPS tracking of multiple parties on a map. There are several apps that show the position of various other parties, but I can't tell how accurate the position is, or how often it is updated. Does anyone know of any published information from Apple that would answer these questions?

Thanks,

Dan

Ive searched everywhere and i cant find anything on it!?

Someone must know. Try emailing/ringing apple support maybe?

Ill keep trying to find out for you, and if you find it first can you please post what you find out?

Thanks

Ben

I have spent some time today searching various developer forums and iphone app forums to see if I could find any answers. It appears from anecdotal evidence that the refresh rate is around 5 seconds. At least that is what several people reported from several apps that track real time movement on google maps. Accuracy is a different matter, and seems to be affected by a variety of factors. In best cases, the GPS seems to be accurate within 10 ft. That requires that you are outside away from tall buildings and in a 3G covered area. It also appears that the various bug fix updates to the firmware are having a significant impact, both good and bad, on GPS accuracy. It looks like it will be a while before all the kinks are worked out between Apple's firmware, and AT&Ts network, and the GPS function. Once they fix all the problems, it looks like this will be a pretty decent sat nav device. I'll keep researching as well. Let me know what you discover.

5 sec and around 10 foot is what I found out from different places too.

Shame apple haven't released offial details really.

Ben