Earth circumference is around 25,000 miles - 132E6 feet. 24 bit mantissa (23
bits plus sign) gives a resolution in this application of around 15.7 feet
since negative measurements don't apply.
---
Oh... 24 bit mantissa should give 1.25 m resolution if my headcounting is
In message 518733c4.1020...@gmail.com, Sarah White writes:
On 5/6/2013 12:29 AM, Mark Sims wrote:
The 48-hour precision survey in Lady Heather uses a statistical
weighted median filter to arrive at its final location instead of
a simple average of fixes. It processes data of one minute, hour,
A subtle point: The GPS satellite orbits are controlled so that their
(nominal) ground tracks precisely repeat every day. To make this work,
their day is not a standard 24-hour day but a sidereal day lasting 23
hours, 56 minutes, and about 4 seconds. The satellites actually go around
the earth
@febo.com
Rubrik: [time-nuts] GPS position survey
Earth circumference is around 25,000 miles - 132E6 feet. 24 bit mantissa (23
bits plus sign) gives a resolution in this application of around 15.7 feet
since negative measurements don't apply.
---
Oh... 24 bit mantissa should
Hi fellow time nuts!
I've recently bought a Trimble Acutime gold that will be used as a
reference clock for a NTP server.
This receiver has the possibility of averaging it's position before
entering what Trimble calls the overdetermined clock state. The
default is to average the position with
In message 8311230247672528820@unknownmsgid, =?ISO-8859-1?Q?Miguel_Barbosa_Go
n=E7alves?= writes:
This receiver has the possibility of averaging it's position before
entering what Trimble calls the overdetermined clock state. The
default is to average the position with 2000 fixes.
What do you
On 5 May 2013 11:51, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 8311230247672528820@unknownmsgid,
=?ISO-8859-1?Q?Miguel_Barbosa_Go
n=E7alves?= writes:
This receiver has the possibility of averaging it's position before
entering what Trimble calls the overdetermined clock state.
Hi
Something like 48 hours is a good idea *if* you have the time to do them.
Bob
On May 5, 2013, at 7:34 AM, Miguel Barbosa Gonçalves m...@mbg.pt wrote:
On 5 May 2013 11:51, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 8311230247672528820@unknownmsgid,
If the only use of the GPS receiver is to drive NTP, then 2,000
seconds is long enough NTP runs at the microsecond level and the tiny
remaining error after 2000 seconds will never be noticed by NTP.
However if you are really nuts and want to do the best you can then
let it run for 12 hours.
In message caedntmsjwt0suxbzdrnz3enyw6xhuvlhvmfw_cmq5r8etay...@mail.gmail.com
, =?ISO-8859-1?Q?Miguel_Barbosa_Gon=E7alves?= writes:
So you think a full day of position survey will be better?
I don't know if it is as sensitive on your lattitude as mine (56N)
but here N*12 hours works best, for as
When doing a position survey, does Lady Heather have to be running?
Or does the Thunderbolt do it by itself?
--
Chuck Forsberg WA7KGX c...@omen.com www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Technology Inc The High Reliability Software
10255 NW
On 5 May 2013 20:18, Chuck Forsberg WA7KGX N2469R c...@omen.com wrote:
When doing a position survey, does Lady Heather have to be running?
Or does the Thunderbolt do it by itself?
I don't know about Thunderbolt but on my Acutime Gold the Windows
software sends the restart survey command to the
On 5/5/2013 6:35 AM, Miguel Barbosa Gonçalves wrote:
Hi fellow time nuts!
I've recently bought a Trimble Acutime gold that will be used as a
reference clock for a NTP server.
This receiver has the possibility of averaging it's position before
entering what Trimble calls the overdetermined
Le 5 mai 2013 à 21:18, Chuck Forsberg WA7KGX N2469R a écrit :
When doing a position survey, does Lady Heather have to be running?
Or does the Thunderbolt do it by itself?
Good question. I would have thought that once started, the survey would
complete even though LH was stopped/started,
On 5 May 2013 12:28, Sarah White kuze...@gmail.com wrote:
I myself did a sampling over a period of 1 million samples
(actually, it was a value of 2^20, not exactly 1 million)
quickest it could have completed such a survey is 12+ days
... However, I had masks set for elevation, signal, etc.
If you are talking about using this with NTP. I don't know if you
have a choice. The Trimble receiver is going to do whatever it is
going to do when you power it up.Software running on a PC can
perform a 24 hour survey and report the location but the Type 29
driver in NTP has no way to tell
Hi Chris!
On 06/05/2013, at 01:21, Chris Albertson albertson.ch...@gmail.com wrote:
If you are talking about using this with NTP. I don't know if you
have a choice. The Trimble receiver is going to do whatever it is
going to do when you power it up.Software running on a PC can
perform
So this is different from the Thunderbolt, even if they both use the
same serial protocol or can the t-bolt also have it's flash rom
programmed from a PC?
The bottle neck in the system in the uncertainty in the interrupt
latency on the PC where NTP runs. After all this I doubt you can
captures
-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] GPS position survey
So this is different from the Thunderbolt, even if they both use the
same serial protocol or can the t-bolt also have it's flash rom
programmed from a PC?
The bottle neck
The 48-hour precision survey in Lady Heather uses a statistical weighted median
filter to arrive at its final location instead of a simple average of fixes.
It processes data of one minute, hour, and overlapping 24 hour intervals to
calculate the final position. It can produce a location
On 5/6/2013 12:29 AM, Mark Sims wrote:
The 48-hour precision survey in Lady Heather uses a statistical weighted
median filter to arrive at its final location instead of a simple average of
fixes. It processes data of one minute, hour, and overlapping 24 hour
intervals to calculate the
Oh... 24 bit mantissa should give 1.25 m resolution if my headcounting is about
right. Thats about 4 ns.
Royal kludge indeed.
Cheers
Magnus
Originalmeddelande
Från: Mark Sims hol...@hotmail.com
Datum:
Till: time-nuts@febo.com
Rubrik: [time-nuts] GPS position survey
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