Hi,<br><br>I don't really have much use for GPS adaptors right now and certainly can't offer you any advice, but I just thought I'd say I found this interesting to read. It's funny how often the most expensive piece of equipment is not the best. I found the same with USB sound cards. The chipset makes all the difference.<br>
<br>Can't wait to see an update on the project once you have it adding GPS data as well. Very cool!<br><br>See ya,<br><br>Dan<br><br><br><br><div class="gmail_quote">On Mon, Jun 13, 2011 at 11:25 PM, Sebastian Arcus <span dir="ltr"><<a href="mailto:shop@open-t.co.uk">shop@open-t.co.uk</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Hi all,<br>
<br>
I'm not sure if there is any interest in this, but during my work to add gps tracking to the cctv bus system, I had to test several usb gps adapters because of variation in behaviour by some of them. The main point of my research so far seem to be that the adapters based on the SirfStar III chipset (which covers a good majority of models available) are pretty low quality. They take a long time to get a fix - specially if they haven't been used in the last 24 hours and have to re-download data from the satellites. On cloudy days - some of them can take 30-40 minutes to obtain the first fix.<br>
<br>
I have enquired on the gpsd mailing list (which, by the way, I wouldn't call "friendly" to say the least). I haven't really obtained much information. They mostly seem to be involved with the "embedded" market - not entirely sure what they mean by that. I could assume they really work for various gps manufacturers - which would explain the really abrupt attitude and at times disguised hostility towards the Linux kernel and tools.<br>
<br>
To cut the story short - I am now the proud owner of 6 gps adapters. The bottom line (and useful conclusion) is that the BluNext BN-903S adapter, based on the Adopt SkyTraq Venus 6 chipset seems to be an excellent piece of hardware. You can just plug it in, and it gets a fix within at worst 2-4 minutes, if you are in between buildings, on a cloudy day, and it hasn't been used for few days. Otherwise, it will get a fix in a matter of seconds.<br>
<br>
The funny thing is that this is the cheapest adapter of all I bought - £16.95 on <a href="http://Amazon.co.uk" target="_blank">Amazon.co.uk</a> with free delivery. It has 65 channels (can listen to 65 satellites at the same time, although I doubt the current constellation has that many satellites anyway) - versus 20 channels for the SirfStar III chip. I'm not sure how much difference that makes in practice, but whatever the reason, it works brilliantly.<br>
<br>
On the other hand, the SirfStar III is always referred to in glowing terms on all websites I've seen adapters for sale. Go figure. Either their marketing machine is one great contraption, or I'm the unlucky owner of 3 different adapters from different manufacturers with their chipset in them - all of them naff.<br>
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In case somebody will find the above useful.<br>
<br>
If anybody else on the list is using usb, serial or bluetooth gps receivers with a computer, I'd be curious of their point of view. Performance of adapters in smartphones might be a little bit skewed, as lots of them also use AGPS over Internet, which makes the the quality of the actual chip more difficult to assess solely on its gps reception merits.<br>
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Hope you are all keeping well,<br>
<br>
<br>
Sebatian<br>
<br>
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</blockquote></div><br>