[Loadstone] Observations on Accuracy with Two Receivers

Kevin Chao g.unit89 at clearwire.net
Mon Oct 22 21:35:59 BST 2007

I am sure that the hdop reading is taken into account when reporting the
accuracy in number of feet.

I am wondering what equation is the LoadStone team using to take the hdop
value and giving the user a number of feet?

Is there a similar equation that can be used for the vdop? I know that the
vertical reading is a lot more flakey and less accurate, but just wondering.



-----Original Message-----
From: loadstone-bounces at loadstone-gps.com
[mailto:loadstone-bounces at loadstone-gps.com] On Behalf Of Michael O. Hanson
Sent: Monday, October 22, 2007 1:25 PM
To: loadstone at loadstone-gps.com
Subject: [Loadstone] Observations on Accuracy with Two Receivers

Changing accuracy from a number to a number of feet was a great improvement.

I don't want to start the great GPS receiver controversy or anything like

Some users might find the information below helpful.  I do not claim that
these test results are anything close to conclusive.  They are my

My testing was not performed under scientific or controlled conditions. 
Other users could get vastly different results for any number of reasons.

I tested a Holux M-2000 and a Royaltec RBT-2110.  I tested both receivers in
my living room and outside.

The Holux got average readings of between twenty and thirty feet.  The
lowest was 20.8 feet.  The highest was thirty feet.

The Royaltec got readings of between fifty-five feet and ninety-four feet. 
The lowest was fifty-four feet.  The highest was ninety-six feet.

The Holux averaged eight to ten out of twelve satellites.  The Royaltec
averaged four out of twelve.

I know the Royaltec is somewhat better at tracking direction changes.  It is
a perfectly usable receiver in my experience.  If there is some factor I am
not taking into account, please let me know.

Mike Hanson

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