45641 Views Previous 1 2 3 4 Next 58 Replies Latest reply: Sep 3, 2008 12:37 AM by Garyuk Go to original post
I did a side by side test with a Hertz Neverlost system in my rental. I found the iPhone GPS to be faster, especially when getting your initial location. It beat the Neverlost by almost a minute in that regard due to the "Assist." On my drive the blue dot stays right with me.
I'm not discounting the problems some of your are having, only suggesting it's not endemic to all iPhone 3Gs.
Message was edited by: KBeat to fix a typo.
The iphone GPS LAGS alot.
Jump in your car or hop on a train then turn on your GPS, and youll see what im talking about.
On the highway, mine was extremely accurate over the course of my drive to and from NH... putting me right under and over the roads crossing the highway. Walking around the city, it seems a bit less accurate, but i was stunned by the performance on the highway. I can hardly wait to have TomTom software on this thing.
I assume the lessened accuracy in the city is due to sketchy Wi-Fi info fighting with the presumably weakened GPS signal, but who knows.
~ Kiran <firstname.lastname@example.org>
Since I've had my iPhone 3G I've been noticing that the GPS dot in Google maps has a very slow refresh. In other words, when I'm walking it doesn't seem to be able to keep up. It will find my location with relative accuracy and then not follow for about 10 seconds. Suddenly it will refresh it's position by sliding to my new location.
The Apple phone rep I spoke to said that Location Services uses WiFi and Cellular triangulation in addition to GPS to determine location and that it can lag because it's trying to get a fix using these sources in combination with the GPS. Since I'm in New York City (the lag also happens in areas where I have a 360 sky view so it's not a signal quality issue) I assume it's location is being confused by WiFi signals along the street.
I assume this is not something that be corrected by 3rd party apps as location is determined at the system level and then passed onto the app which takes whatever it can get.
It seems to me that for accuracy reasons and for the benefit of reduced power consumption that Location Services in preferences should have two switches: one for WiFi/Celluar and one for GPS so that users can control how location is determined. There should also be some kind of feedback as to GPS health (either in info, at the location services prefs, or along the status bar, next to the WiFi/cell bars.
I believe this is a hardware issue and cannot be change with a software update. The GPS in the iPhone is not like a regular full blown GPS device such as GARMIN AND TOM TOM. The GPS won't work every where like you want it to because it using assist signal from WIFI and Cellular triangulation. Think about it...you get what you pay for...A GPS device alone from GARMIN and TOM TOM already cost $199+ by it self.
According to tear down reports, the GPS is pretty high performance:
If you look at the PDF you can see that the various modes seem to be user (or software) modifiable as part of its "multi-mode operation".
This is the same chip (actually a more updated version) that TomTom uses.
The same happened to me in a particular area of Rome, Italy. While staying in a house there, I kept getting a "general location" (radius) lock in Tirana, Albania.
Once outside and less than a km away from there, both the initial "radius" and the subsequent pinpoint were placed correctly.
My take is that there's a problem with the iPhone ability to locate the cell tower it's connected to. When inside a condo, it can't get any GPS signal, so it was relying exclusively on cell tower location—and somehow it thought that particular cell tower was in Albania. It is also worth noting that my carrier, Vodafone, has branches in both Italy and Albania.
I don't think the error originated from Wi-Fi networks in the area because there were no commercial-grade WLANs around, and I sure hope Apple doesn't have all personal wireless routers in the world mapped for their A-GPS application!
What kind of Wireless Router do you have?
Was it ever used in in Italy? There is another report on here of somebody who moved from New York to the UK, and Skyhook still had her router listed as New York.
Even if your router was never used in Italy, you should contact Skyhook to update the WiFi location for your router. This article has more information:
Hope this helps,
yes, apple (google maps app), via skyhookwireless, has all major metro areas wifi routers mapped. in the US, UK, Germany, France and other countries in europe. italy is florence, rome, milan and others...
the different type of positioning are easy to distinguish by the radius of the circle:
GSM positioning: 1-4km radius
WPS positioning: 100-250m radius
GPS positioning: blue dot with a 50-100m transparent circle..
to check coverage: http://skyhookwireless.com/howitworks/coverage.php
and skyhook has loki, http://www.loki.com/ , their service to take advantage of that data with layers in google maps.
i have a different discovery:
google maps positioning works great in my case, on my iphone 2G with WPS as the source of geocoordinates. but the iphone camera writes different data into the EXIF! there's other apps, like twitteriffic, that do the same! apps that work correctly are airme, twinkle, zintin and exposure. those are the apps i have tested for correct geo location data supplied by the iphone API...
anyone else has seen this odd behavior by the iphone camera app and other apps? and if so, do you have apps that get it right, like in my case google maps, airme, twinkle, zintin and exposure???
the web address to change wifi router data: http://www.skyhookwireless.com/howitworks/submit_ap.php
you only need the MAC address of the wifi router or multiple routers to change the location of them. even on the go you can do this, let's say in your favorite spot you notice that the location is not 100% correct, go to the website (http://www.skyhookwireless.com/howitworks/submit_ap.php) and change the location after you checked for the mac addresses of the wifi routers your iphone or other hardware sees. i use my macbook pro for that... or APlogger on the iphone, but i think now with iphone osX 2.0 APlogger hasn't been updated yet...