View previous topic :: View next topic |
Author |
Message |
RobMob Regular Visitor
Joined: 31/12/2002 09:37:48 Posts: 103
|
Posted: Thu Sep 06, 2007 11:07 pm Post subject: Assisted GPS vs Sirf III? |
|
|
I am in the market for a pocket PC with built in GPS. I am weighing up the soon to be launched Eten x800 and the HTC TY-TN II. I understand the x800 will have Sirf III but no querty and the HTC will have querty but assisted GPS.
Can someone tell me which is better out of Assisted GPS and SIRF III. I know what SIRF III is but don't really understand much about Assisted GPS and whether it is superior or inferior to Sirf.
Many thanks
Rob |
|
Back to top |
|
|
mikealder Pocket GPS Moderator
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
|
Posted: Fri Sep 07, 2007 6:27 am Post subject: |
|
|
Assisted GPS is where the device stores a small file containing the orbit positional data of the GPS Satellites, it is valid for 72 Hours, once it has expired you either connect the device to the PC for t to download the free update to cover the next 72 hours or use the on board phone to connect and download.
The data packets are very small, I find my HTC Artemis devices (which both use Assisted GPS) are extremely quick to acquire a positional fix, faster than my SiRF-III based units, other than time to fix AGPS doesn't do much else - Mike |
|
Back to top |
|
|
robertn Frequent Visitor
Joined: Feb 06, 2005 Posts: 564
|
Posted: Mon Sep 10, 2007 1:20 am Post subject: |
|
|
You need to be in cellular coverage area for assited GPS to be of help - an overlooked issue for some people.
Assisted GPS sends you the data the GPS needs to aquire before it can get a fix. This data is sent from the cell site, which is close enough to you that it is useful. Without this data, the GPS looks for a satalite, then waits for the data to be sent. Once this is complete, it can then calculate a fix.
Essentially, the Assited GPS does a Hot Start each time you turn the GPS on. |
|
Back to top |
|
|
|
Posted: Today Post subject: Pocket GPS Advertising |
|
|
We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
Have you considered making a donation towards website running costs?. Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
|
|
Back to top |
|
|
|