[OZAPRS] APRS resolutions

[Andrew Rich]

The UI-VIEW resolution stated was tested using ui-view to RF, and by
changing just the last digit of the lat or lon, and then using th big loop
and looking at google earth and measuring the distance using the google
earth ruler.

What was really interesting was when I used the "raw" gprmc string on
APRS,
I was able to get the full difference in distance on google earth.

For example

UI-VIEW:

Sending 2734.44S then 2734.45S yielded a distance change of 16 meters.

Sending
$GPRMC,211210,A,2734.4431,S,15306.2525,E,0.0,338.8,150406,11.0,E,A*37
Sending
$GPRMC,211210,A,2734.4432,S,15306.2525,E,0.0,338.8,150406,11.0,E,A*37

yielded a difference (and still passed by APRS) of some cm's in
resolution.

So the GPRMC string was heaps better.

Cheers


-----------------------------------------
Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec at tech-software.net <mailto:vk4tec at tech-software.net>
web: http://www.tech-software.net
Brisbane AUSTRALIA



-----Original Message-----
From: Richard Hoskin [mailto:rhoskin at bigpond.com]
Sent: Friday, 2 March 2007 8:41 PM
To: vk4tec at tech-software.net; 'VK / ZL APRS Users'
Subject: RE: [OZAPRS] APRS resolutions



Is the resolution you are referring to from a posit broadcast on RF or a
direct reading from UI-View with no RF involved?

Is the 16 metres relating to Longitude or Latitude and is it linear with
Latitude?

Did you know that a Compressed posit in APRS / UI-View is more accurate
than
a non-compressed posit.

Cheers
Richard


-----Original Message-----
From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On
Behalf Of Andrew Rich
Sent: Friday, 2 March 2007 8:28 PM
To: ozaprs
Subject: [OZAPRS] APRS resolutions

Been doing some testing.

Changing the last digit on my position in ui-view position, gives me a 16
meter difference in position.

Google earth allows me to have a 13 cm difference.

Food for thought

-----------------------------------------
Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec at tech-software.net
web: http://www.tech-software.net
Brisbane AUSTRALIA

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