From: Mark Sims
Yes. It also works with GPSD so should be able to work with any device that
GPSD supports. It also works with most common GPS receiver native binary
languages and provides full device control.
---
Thanks, Mark. I look forward to playing with a copy. I
Yes. It also works with GPSD so should be able to work with any device that
GPSD supports. It also works with most common GPS receiver native binary
languages and provides full device control.
---
> This looks to be a most useful and helpful display. Will the program do
The interpolation does not spread the data to where sats have not
appeared... what it effectively does is intelligently make the dots
bigger... but only along the azimuth "axis".
For each elevation angle, it starts at azimuth 0 degrees and searches
forward until it sees a point with signal.
> I'd like to try something like a Voronoi tessellation, but that gets
rather nasty to implement..
There's a boost library...
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The interpolation does not spread the data to where sats have not appeared...
what it effectively does is intelligently make the dots bigger... but only
along the azimuth "axis".
For each elevation angle, it starts at azimuth 0 degrees and searches forward
until it sees a point with signal
Mark wrote:
The tricky bit is interpolating signal levels between logged points (there is a
display options for showing the raw signal level data). Heather interpolates
between adjacent azimuth points at each elevation angle.
I always wondered about the "filled in" (interpolated) plot. To
The colored signal level vs az/el plot follows that convention... outer edge
is the horizon, center point is zenith (90 degrees above the horizon). Color
represents the average signal level seen at a given point in the sky.
The tricky bit is interpolating signal levels between logged point
On 11/22/16 10:13 AM, Mark Sims wrote:
Attached is a screen shot from Lady Heather showing various antenna signal
displays. The antenna was a cheap GPS/GLONASS patch antenna (mounted on a 3
foot ground level tripod ) connected to a rather nice NVS-08 receiver tracking
GPS, SBAS, and GLONASS s
That screen is one of the features in the next (5.0) release. If you click the
mouse on one of the signal level maps in that display, it will zoom that one
to full screen.
Besides the normal "zoom" keyboard commands, with the 5.0 release you can also
zoom the clock/watch/sat map/signal level
time-nuts@febo.com
Subject: [time-nuts] How can I measure GPS Antenna quality?
Attached is a screen shot from Lady Heather showing various antenna signal
displays. The antenna was a cheap GPS/GLONASS patch antenna (mounted on a 3
foot ground level tripod ) connected to a rather nice NVS-08 rec
Attached is a screen shot from Lady Heather showing various antenna signal
displays. The antenna was a cheap GPS/GLONASS patch antenna (mounted on a 3
foot ground level tripod ) connected to a rather nice NVS-08 receiver tracking
GPS, SBAS, and GLONASS satellites (typically around 22 sats).
Th
Hi Atilla,
Read the document below
https://www.ngs.noaa.gov/ANTCAL/docs/NGSantcalprocedures.pdf
And the reference within
antenna_README.pdf
Antennas are generally not calibrated individually by the user. You make sure
the antenna you buy are in the ANTCAL or Geo++ lists. Any use of a snow
On 11/21/16 10:10 AM, Tom Van Baak wrote:
For the equipment hobbyists usually have, the phase center is not that
important. Most antennas have a variation <5mm. Even 10mm would lead to
just a ~33ps variation.
I agree. And besides, for those of us here in Oregon/Washington, the very
ground is m
On 11/21/16 2:58 PM, Attila Kinali wrote:
On Mon, 21 Nov 2016 08:22:50 -0800
jimlux wrote:
I'm not sure about whether an anechoic (which is really "hypoechoic")
chamber is going to get you the data you need. Calibrating the chamber
to the needed level of accuracy might be harder than doing fi
On Mon, 21 Nov 2016 08:22:50 -0800
jimlux wrote:
> I'm not sure about whether an anechoic (which is really "hypoechoic")
> chamber is going to get you the data you need. Calibrating the chamber
> to the needed level of accuracy might be harder than doing field
> measurements.
[...]
> sin(2
> For the equipment hobbyists usually have, the phase center is not that
> important. Most antennas have a variation <5mm. Even 10mm would lead to
> just a ~33ps variation.
I agree. And besides, for those of us here in Oregon/Washington, the very
ground is moving northwest at several inches per y
On 11/21/16 8:38 AM, Bob Camp wrote:
Hi
On Nov 21, 2016, at 9:54 AM, Attila Kinali wrote:
On Sun, 20 Nov 2016 14:13:58 -0800
Hal Murray wrote:
If I gave you a pile of data, how would you compute a quality number? Can I
just sum up the S/N slots for each visible/working satellite?
If “s
When I was doing VHF and UHF direction finding antenna design, I would
drive out to the highest readily accessible hilltop for testing. Once
I came up with a low sidelobe design, I started picking up things like
lamp posts, trees, and bushes in the parking lot, aircraft over LAX
and John Wayne air
Hi
> On Nov 21, 2016, at 9:54 AM, Attila Kinali wrote:
>
> On Sun, 20 Nov 2016 14:13:58 -0800
> Hal Murray wrote:
>
>> If I gave you a pile of data, how would you compute a quality number? Can I
>> just sum up the S/N slots for each visible/working satellite?
If “sum the S/N” gives you a d
On 11/21/16 6:54 AM, Attila Kinali wrote:
On Sun, 20 Nov 2016 14:13:58 -0800
Hal Murray wrote:
If I gave you a pile of data, how would you compute a quality number? Can I
just sum up the S/N slots for each visible/working satellite?
There are multiple issues. As already mentioned, SNR is on
On 11/21/16 4:15 AM, Bob Camp wrote:
Hi
At spectrum analyzer bandwidths, the GPS signals out of the antenna are
more than 20 db below the noise floor. You can’t see them with an analyzer.
You need to run things into the equivalent of a receiver to turn it into
anything
you can see above the noi
On Sun, 20 Nov 2016 14:13:58 -0800
Hal Murray wrote:
> If I gave you a pile of data, how would you compute a quality number? Can I
> just sum up the S/N slots for each visible/working satellite?
There are multiple issues. As already mentioned, SNR is only a part of the
picture. What you are lo
In message <2974f356-3729-448e-a428-dc4d340ff...@n1k.org>, Bob Camp writes:
>If I put up a handful of antennas on the back porch, I can indeed hook them
>up to various receivers and cables.
I actually had a chance to do that once:
http://phk.freebsd.dk/raga/
I was very careful
On 11/20/16 7:41 PM, Mark Sims wrote:
When I was developing the precision survey code for Lady Heather, I
used a lot of antennas. My definition of antenna quality boiled down
to how well the results of a 48 hour survey compared to the cm level
survey point that I had for my antenna position (fr
>> and avoids the geometry and pre-calibration issues, as well as environment
>> and local reference effects. Rubidium would be sufficient. It's possible the
>> first minute of each segment may be weird (as the receiver switches from
>> lost to lock mode), but you can han
Yo Hal!
On Sun, 20 Nov 2016 14:13:58 -0800
Hal Murray wrote:
> Is that even a sensible question?
Yes, it is a good question.
I have been buying a lot of cheap GPS antennas for testing on RasPis.
I plug the antenna into a GPS, then just wait until the GPS gets a good
sky view, and then check t
When I was developing the precision survey code for Lady Heather, I used a lot
of antennas. My definition of antenna quality boiled down to how well the
results of a 48 hour survey compared to the cm level survey point that I had
for my antenna position (from a Ashtech Z12 receiver / matched c
e sufficient. It's possible the
> first minute of each segment may be weird (as the receiver switches from lost
> to lock mode), but you can handle that in your data reduction.
>
> /tvb
>
> ----- Original Message -
> From: "Hal Murray"
> To:
> Cc: &qu
If you run two antenna simultaneously then...
1) they both can't be at the same location and
2) What if the two antenna interfere one with the other.
I think maybe you need to collect data over a long enough period of tine
that wether averages out. the satellite tracks repeate pretty much exact
in your data reduction.
/tvb
- Original Message -
From: "Hal Murray"
To:
Cc: "Hal Murray"
Sent: Sunday, November 20, 2016 2:13 PM
Subject: [time-nuts] How can I measure GPS Antenna quality?
>
> Is that even a sensible question? Is there a better way to phrase
You need a definition of "Quality" to work with.
One definition might be "does it meet published specs? under what
conditions?"
Another definition might be associated with reliability and ruggedness.
Longevity in outdoor conditions.
Another might be with the antenna supporting your use case.
Anoth
Is that even a sensible question? Is there a better way to phrase it?
The problem I'm trying to avoid is that the weather and the satellite
geometry change over time so I can't just collect data for X hours, switch to
the other antenna or move the antenna to another location, collect more dat
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