-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 giv
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 ear
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
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 abo
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
Datum:
Till: time-nuts@febo.com
Rubrik: [time-nuts] GPS position survey
The 48-hour precision
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
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 tha
ncy measurement
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 in the system in the uncertainty in the interru
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 th
Hi Chris!
On 06/05/2013, at 01:21, Chris Albertson 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 a 24 hour survey and r
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
On 5 May 2013 12:28, Sarah White 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.
> (result
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 5/5/2013 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 overdete
On 5 May 2013 20:18, Chuck Forsberg WA7KGX N2469R 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 antenna and
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 N
In message
, =?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 big a N as you have
patience for, up to about 10
--
Poul-Hennin
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. That
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 wrote:
> On 5 May 2013 11:51, Poul-Henning Kamp wrote:
>
>> In message <8311230247672528820@unknownmsgid>,
>> =?ISO-8859-1?Q?Miguel_Barbosa_Go
>> n=E7alves?=
On 5 May 2013 11:51, Poul-Henning Kamp 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. The
> >de
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
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 200
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