[standards-jig] Re: jep-0080 (geoloc)

Timothy Carpenter timbeau_hk at yahoo.co.uk
Thu Sep 25 17:24:40 UTC 2003


On 25/9/03 6:03 pm, "standards-jig-request at jabber.org"
<standards-jig-request at jabber.org> wrote:

> Message: 2
> Date: Wed, 24 Sep 2003 13:05:11 -0400 (EDT)
> From: Matt Mankins <mankins at media.mit.edu>
> To: standards-jig at jabber.org
> Subject: Re: [standards-jig] jep-0080 (geoloc)
> Reply-To: standards-jig at jabber.org
> 
>> I think what is meant here is the difference between someone manually
>> updating their location info (for example when you went from your home to
>> your work, you activate a script that publishes the coordinates of your
>> office) and an automatic system wich (for example based on GPS or AGPS)
>> frequently updates your location. I suppose it could be usefull to know
>> wich method is used.
> 
> Perhaps this is just accuracy of the location reading?
> 
> "I know for sure I'm on Planet Earth"
> "I'm pretty sure I'm in North America"
> "It looks like maybe Boston"
>  "Wild guess would be Inman Square"
> 
> vs
> 
> "Definately at 42.3737 N, 71.1010 W"
> 
> 
> 
> .
> .
> .
> There's more uses for accuracy information, including the "freshness" of
> the reading.  
> 
And the quality...

GPS can be accurate from 30m right down to 1cm if you have a fixed
reference.

It is worth indicating if it is automatically given to a mobile unit or
automatically PRODUCED by a mobile unit. I for one can pick up GPS over my
Bluetooth link from my in-building GPS unit. This could as easily be sent
over a WiFi link at a hotspot and thus 100m+ radius from the reference. Thus
I can automatically publish "I am at 5130.12535N 00019.21783W" but should
also be able to say if it is a location given by a static, accurate device
or from a truly mobile GPS PDA. GPS protocols also have the ability to send
quality information and accuracy signals, so you can differentiate from a
standard GPS of 30m scraping by on 3 satellites and a RTK carrier phase DGPS
of 2.04cm accuracy using 6.

Another form could be "I am using Starbucks 5th Ave WiFi hotspot"...

As to 'fresh' GPS gives UTC along with the fixing so that could
help...though THAT all sounds a bit Minority Report for me...

Tim

> Mankins
> 
> 




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