does wi-fi effect GPS accuracy

开发者_如何学GoI want to know if wi-fi affects GPS accuracy if I used GPS using CLLocationManger in my application.

I was going to add this as a comment, but it really won't fit.

Edit: This is probably a clearer way of putting it.

1. Phone turns on GPS, begins GPS signal search
2. Phone scans for Wifi Access Points, Cell Towers, captures IDs
3. Phone sends captured IDs to Vendor's servers
4. Vendor's servers respond with any known location(s) of Wifi APs and towers, and possible other meta-data useful in reducing search-space.
5. Phone uses that data to get an approximate location
6. Phone feeds that approximate location back to the GPS software, reducing possible search space.
7. When phone gets lock, periodically sends back Wifi APs and Cell Towers seen plus the known GPS fix to vendor's DB.

Many vendors do this, it's not just Apple.

WiFi (and/or cell tower triangulation) assists the GPS to give you a location faster, but it doesn't make the location more accurate.

EDIT - Apple recommends turning ON Wi-Fi and cellular network connections to assist in locating GPS satellites faster in article HT1975 which says:

"Verify that you have a cellular or Wi-Fi network connection. This allows the Assisted GPS (A-GPS) on the device to locate visible GPS satellites faster, in addition to providing initial location information using the Wi-Fi or cellular networks. "

No, WiFi and GPS use a different frequency (2.4-2.5 and 1.2-1.5 Ghz).