Barry,
2 cents to go with yours. Maybe we’ll get =
to a
cup of coffee if others join.
Last winter I worked through many free software =
programs and
tips available to the PSN at no cost for calibration and testing. =
Yes
there are good options available. There is much room to improve =
and adapt
them to our specific needs and configurations but source code is =
available for
some and for others the original programmer or designers are part of =
PSN.
In my opinion even as an amateur it is desirable to at least see how my =
station
fits performance wise or to compare a change I make to my previous
standard.
Noise in instruments – I found methods to =
correlate
instruments at the same location. I believe they similar or same =
as Brett
and Dave use but I have yet to try them out. =
Noise in location – John Lahr provided =
comparison of
AS1 to NLNM along with program and code to accomplish this with any
instrument. USGS also provides PDFSA which runs on LINUX and is =
subject
to 30 sps minimum sample rate and some file formats not easily created =
with
current PSN software. Both programs require instrument calibration
information but in differing formats. I suspect PDFSA could run =
under
CygWin but have not explored or tested this. Noise testing could =
be
periodic and provided by one or more members or on a server without =
setting up
all the programs individually.
Accurate time – GPS seems to be the common =
standard in
the US
at least. My personal opinion is that data collection methods do =
not
maintain the GPS standard when only start time and data points are
maintained. I see collection drift caused by the operating system =
greatly
increased by use of certain other programs on a shared computer. =
Data Format – mini-SEED format and calibration =
files
are required for some of the programs available and this is the format
available from USGS. It is complicated and I have not found a =
workable direct
conversion from or to PSN format. Programming a converter is beyond my
expertise as is creating the calibration file =
format.
Calibration – The programs from =
Dr
Weilandt work and are fairly easy to implement in a home environment =
using a 2
channel AD. I found 2 ways to use them with PSN data. One =
method is
to simply save your PSN data as text and then edit a proper header at =
the
beginning. For the second method I have a conversion program from =
PSN to
the CALEX format used by the original program. Some way to convert =
the
results to a SEED response file would allow use with the PDFSA noise =
software.
My notes can be linked to here: http://mit.midco.net/rpratt/images/Calibration%20using%20fre=
e%20Programs.pdf
An idea would be to form some loose working groups =
and
provide ideas but I also think we should be careful not to make PSN =
something
new people might be afraid of or feel a need to measure up. =
Developing
interest in seismology by students and lurkers could be our most =
important
contribution and does not require professional grade instrument =
performance but
yet our more skilled members should take it as far as the technology can =
reach.
As compared to other groups on the net we seem to have the best in =
respect to all
members and to sharing openly our thoughts from professional to new =
member.
Randy
| Message
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'------ ------ =
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Subject: Re: =
diamagnetic
levitation seismometer possibility
From:
Barry Lotz <barry_lotz@.............>
Date: Mon,
16 Jul 2012 19:19:03 -0700 (PDT)
---1540918134-1195055643-1342491543=3D:75038
Content-Type: =
text/plain;
charset=3Dus-ascii
Angel & =
Dave
I agree. How =
do we
move forward?
My 2 cents: I =
work for
a structural testing and inspection lab. Our lab and inspectors comply =
with
certain standards so that our results/inspections are credible ( eg =
NIST, ASTM,
AWS, ICC). Maybe it would be possible to have an accepted protocol for =
our
stations with sensor(s). I would like to comment on the items you =
mentioned.
>"We have =
noisy
instruments"
It =
seems
possible to determine the instrument noise by maybe "nesting"? =
Site
noise could be evaluated over "X" time during day,night or =
both.
Could it mirror the evaluation of professional systems? It seems a =
threshold
could be determined for credibility station/sensor noise limits. Do we =
use the
NLNM graph with an envelope of limits?
>"We do not
calibrate"
Could =
a
accepted standardized procedure be described for horizontal and vertical
sensors, that all could use? I am familiar with methods that Dave and =
Brett use
for our FBV's.
>"We do not =
have
accurate time"
=
Would ,
as an example, larry's SDR program and ADC unit with GPS time be =
sufficient?
What would be an accepted variational =
allowance?
>"We do not =
use a
standard format for data exchange"
Could a documented conversion program(s) be used to convert from say psn =
to an
"standard" format? Maybe it already =
exists.
> "We do =
not use
standard naming conventions"
Should we have a described procedure for =
this?
I think Dr Weilandt =
has
programs which could address some of the noise and =
calibration issues =
above. I
haven't completely read it but is the NMSOP what =
professionals use? =
Could we
have something similar with more nuts and bolts =
procedures and =
info?
=
General
agreement maybe the biggest hurdle, but I agree we should make an =
effort to have more =
credible
stations and sensors if we desire. Maybe we just =
needs some agreed =
upon
documented standards to try to achieve.
Regards
Barry