Survey plot as art.
This is the survey from my Trimble NTBW50AA. It looks like some
bacteria floating around.
The curious thing are the excursions. Rather than being noise like,
some follow a distinct
path. But this is only over a few seconds so it seems unlikely that
they are caused by
weather conditions. The survey from my Resolution T taken at the same
time and using
the same antenna (with a splitter) shows much less orderly excursions
and is more noise
like.
Trimble NTBW50AA survey.
Resolution T survey
Pete.
Try again;
Pete.
On 1/7/2017 12:54 PM, Peter Reilley wrote:
This is the survey from my Trimble NTBW50AA. It looks like some
bacteria floating around.
The curious thing are the excursions. Rather than being noise like,
some follow a distinct
path. But this is only over a few seconds so it seems unlikely that
they are caused by
weather conditions. The survey from my Resolution T taken at the
same time and using
the same antenna (with a splitter) shows much less orderly excursions
and is more noise
like.
Trimble NTBW50AA survey.
Resolution T survey
Pete.
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Yo Peter!
On Sat, 7 Jan 2017 12:54:45 -0500
Peter Reilley preilley_454@comcast.net wrote:
This is the survey from my Trimble NTBW50AA. It looks like some
bacteria floating around.
You can get those from any GPS using the program gpsprof from gpsd.
See attached for a 24 plot from a stationary GlobalSat MR-350P
I find these plots very useful when comparing GPS models.
RGDS
GARY
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
Hi
The “simple” answer is that the weird legs going out from the central blob are
the result of multi-path / reflections in the received signal. With enough data you
might be able to correlate them to observed obstructions. The simulation modeling
required to make that happen might be a bit complex…..
Bob
On Jan 7, 2017, at 3:07 PM, Gary E. Miller gem@rellim.com wrote:
Yo Peter!
On Sat, 7 Jan 2017 12:54:45 -0500
Peter Reilley preilley_454@comcast.net wrote:
This is the survey from my Trimble NTBW50AA. It looks like some
bacteria floating around.
You can get those from any GPS using the program gpsprof from gpsd.
See attached for a 24 plot from a stationary GlobalSat MR-350P
I find these plots very useful when comparing GPS models.
RGDS
GARY
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
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How do you display the survey plot in LH? i.e. the keyboard commands
-=Bryan=-
From: time-nuts time-nuts-bounces@febo.com on behalf of Peter Reilley preilley_454@comcast.net
Sent: January 7, 2017 9:54 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Survey plot as art.
This is the survey from my Trimble NTBW50AA. It looks like some
bacteria floating around.
The curious thing are the excursions. Rather than being noise like,
some follow a distinct
path. But this is only over a few seconds so it seems unlikely that
they are caused by
weather conditions. The survey from my Resolution T taken at the same
time and using
the same antenna (with a splitter) shows much less orderly excursions
and is more noise
like.
Trimble NTBW50AA survey.
Resolution T survey
Pete.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
Yo Bob!
On Sat, 7 Jan 2017 15:16:34 -0500
Bob Camp kb8tq@n1k.org wrote:
The “simple” answer is that the weird legs going out from the central
blob are the result of multi-path / reflections in the received
signal. With enough data you might be able to correlate them to
observed obstructions.
I have lots of data from GPS with the antennas mounted 1 inch apart.
They show different weird legs, so I suspect that local geology/architecture
is not the whole story.
For example, compare the plot I just sent, to the one attached here.
Two GPS right next to each other, very differently looking plots.
I'll admit to never generating plots over the same time interval, I'll
start a 24 hour test of two GPS right now.
RGDS
GARY
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
You start a precision survey with this command;
sp
You are offered 48 (hour) survey as an option. I think that you can go
up to 96 hours.
During the survey the scatter plot is displayed.
Pete.
On 1/7/2017 3:32 PM, Bryan _ wrote:
How do you display the survey plot in LH? i.e. the keyboard commands
-=Bryan=-
From: time-nuts time-nuts-bounces@febo.com on behalf of Peter Reilley preilley_454@comcast.net
Sent: January 7, 2017 9:54 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Survey plot as art.
This is the survey from my Trimble NTBW50AA. It looks like some
bacteria floating around.
The curious thing are the excursions. Rather than being noise like,
some follow a distinct
path. But this is only over a few seconds so it seems unlikely that
they are caused by
weather conditions. The survey from my Resolution T taken at the same
time and using
the same antenna (with a splitter) shows much less orderly excursions
and is more noise
like.
Trimble NTBW50AA survey.
Resolution T survey
Pete.
time-nuts mailing list -- time-nuts@febo.com
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www.febo.com
time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ...
and follow the instructions there.
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Hi
In terms of multipath at GPS frequencies, a couple of inches is a lot. Also unless you have
pretty good antennas (as in much larger than 1” each) they will have phase issues unique
to each antenna. Phase cancellation and addition is what gives you multipath.
Bob
On Jan 7, 2017, at 4:00 PM, Gary E. Miller gem@rellim.com wrote:
Yo Bob!
On Sat, 7 Jan 2017 15:16:34 -0500
Bob Camp kb8tq@n1k.org wrote:
The “simple” answer is that the weird legs going out from the central
blob are the result of multi-path / reflections in the received
signal. With enough data you might be able to correlate them to
observed obstructions.
I have lots of data from GPS with the antennas mounted 1 inch apart.
They show different weird legs, so I suspect that local geology/architecture
is not the whole story.
For example, compare the plot I just sent, to the one attached here.
Two GPS right next to each other, very differently looking plots.
I'll admit to never generating plots over the same time interval, I'll
start a 24 hour test of two GPS right now.
RGDS
GARY
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
<uputronics.png>_______________________________________________
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and follow the instructions there.
Yo Bob!
On Sat, 7 Jan 2017 16:16:44 -0500
Bob Camp kb8tq@n1k.org wrote:
In terms of multipath at GPS frequencies, a couple of inches is a
lot. Also unless you have pretty good antennas (as in much larger
than 1” each) they will have phase issues unique to each antenna.
Phase cancellation and addition is what gives you multipath.
I see up to 10x better/worse between GPS brands. Measured by CEP(). A
much smaller change between antenna models. I also have interchanged
antennas between my GPS to rule them out as the major contributing
source to error and discard the worst ones.
I just started 24 hour plots of 4 adjacent GPS. I guess tomorrow I'll
rotate the antennas between GPS, witout moving the antennas, and repeat.
I suspect we may be just seeing different aspects of the same thing. A
big difference between GPS models is probably the quality of multipath
rejection. And I can easily change my GPS, but chaning my geoplogy is a
lot harder.
RGDS
GARY
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
In my case (the original post) there can be no multipath difference,
same antenna and done at the same time.
The length of the cables from the amplified splitter are about the same;
within inches.
This must be some difference in the receiver, perhaps in the math?
Pete.
On 1/7/2017 4:16 PM, Bob Camp wrote:
Hi
In terms of multipath at GPS frequencies, a couple of inches is a lot. Also unless you have
pretty good antennas (as in much larger than 1” each) they will have phase issues unique
to each antenna. Phase cancellation and addition is what gives you multipath.
Bob
On Jan 7, 2017, at 4:00 PM, Gary E. Miller gem@rellim.com wrote:
Yo Bob!
On Sat, 7 Jan 2017 15:16:34 -0500
Bob Camp kb8tq@n1k.org wrote:
The “simple” answer is that the weird legs going out from the central
blob are the result of multi-path / reflections in the received
signal. With enough data you might be able to correlate them to
observed obstructions.
I have lots of data from GPS with the antennas mounted 1 inch apart.
They show different weird legs, so I suspect that local geology/architecture
is not the whole story.
For example, compare the plot I just sent, to the one attached here.
Two GPS right next to each other, very differently looking plots.
I'll admit to never generating plots over the same time interval, I'll
start a 24 hour test of two GPS right now.
RGDS
GARY
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
<uputronics.png>_______________________________________________
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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