From: Darrell Robinson [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Sunday, March 30, 2008 3:19 AM
Subject: Re: [time-nuts] Another Trimble Tbolt question
More guessing. I wonder if the altitude you see is from the difference
In a message dated 30/03/2008 07:47:57 GMT Daylight Time, [EMAIL PROTECTED]
writes:
My guess is that at least some of the difference that you see in your
altitude is from the propagation delay in the cable between your antenna and
the GPS module.
Guessing still further, I would think that
From: Darrell Robinson [EMAIL PROTECTED]
Subject: Re: [time-nuts] Another Trimble Tbolt question
Date: Sat, 29 Mar 2008 23:41:36 -0700
Message-ID: [EMAIL PROTECTED]
I am not an expert.
My guess is that at least some of the difference that you see in your
altitude is from the propagation
From: [EMAIL PROTECTED]
Subject: Re: [time-nuts] Another Trimble Tbolt question
Date: Sun, 30 Mar 2008 05:46:10 EDT
Message-ID: [EMAIL PROTECTED]
Nigel,
I think that's all rather optimistic, as mentioned previously height
estimation is the most innacurate parameter to be reported by GPS
Hello, All--
Darrell Robinson said:
My guess is that at least some of the difference that you
see in your altitude is from the propagation delay in the
cable between your antenna and the GPS module.
Guessing still further, I would think that the position as
reported would be some distance
I hope this post is considered appropriate, if not please let me know and
accept my advance apologies.
I have several NI PCI GPIB cards that are surplus to my requirements.
I was intending to put them on Ebay but thought I would offer them here
first.
These are the older style and were
Hi Michael,
On Sun, 2008-03-30 at 08:50 -0400, Michael Baker wrote:
Just for the sake of illustration, lets suppose that the
antenna is on my roof 20 feet above the ground but that
it took 150 feet of cable to get to the receiver.
Presumably, with no other information, the determined
No because the GPS receiver takes into account the signals from more than
one satellite. What matters is the relative phase of these signals as they
reach the antenna. The relative phase of these signals does not change as
the signals go down the cable. The delay in the cable is inconsequential as
On Sun, 2008-03-30 at 05:46 -0400, [EMAIL PROTECTED] wrote:
-
I think that's all rather optimistic, as mentioned previously height
estimation is the most innacurate parameter to be reported by GPS units.
Height is about 1.6 to 1.8 times worse than horizontal
I think this may have been pointed out already but the altitude reported
by the T'bolt is the WGS84 altitude, which is not at all the same as
the altitude on your USGS map.
If you look up WGS84 in wikipedia you will find a better explanation of
that than I could ever give.
Some of the gps
Fellow time-travelers,
On the Rockwell Jupiter-8 GPS modules: What's the type of RF connector?
I've never seen it before, and I need to find a mating part for it.
Thanks much.
-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner Head Hardware Heavy,
Blue Feather Technologies --
Bruce Lane wrote:
Fellow time-travelers,
On the Rockwell Jupiter-8 GPS modules: What's the type of RF connector?
I've never seen it before, and I need to find a mating part for it.
Thanks much.
How about an image with a scale?
Hi, Hadley,
That ties with what I've figured out so far, thanks.
There you have it, folks: MCX connector. And that makes sense based on
the measurements I took with calipers as well (about 4.5mm outside diameter).
Happy tweaking.
*** REPLY SEPARATOR
The relationship between phase noise and Allan variance is
a complex one and was described in papers at FCS in 1976
and 1978 by my previous manager Mike Fischer (then of HP).
I think these papers come closest to answering your question.
Rick Karlquist
Jeff Mock wrote:
This is a half-baked idea
Richard (Rick) Karlquist wrote:
The relationship between phase noise and Allan variance is
a complex one and was described in papers at FCS in 1976
and 1978 by my previous manager Mike Fischer (then of HP).
I think these papers come closest to answering your question.
Rick Karlquist
Missing formula attached
bruce
inline: AVARCalc___
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