Thank you all for all the good advice!
Cheers,
Miguel
On 16 September 2011 00:10, wrote:
> I have a program called Expertgps that seems to be accurate, but uses old
> b&w imagery.
>
> I think they fixed the bug, but it used to be that the windows and linux
> version of google earth would show d
I have a program called Expertgps that seems to be accurate, but uses old b&w
imagery.
I think they fixed the bug, but it used to be that the windows and linux
version of google earth would show different dates for the imagery.
___
time-nuts mailing
Miguel,
Google Maps data are not in any way a technical product, they are
intended to be used for the layman as a (very) useful tool for finding
places, marketing and so, but you can't give for granted any kind of
precision either positional or even temporal.
I personally have measured known (
On Wed, Sep 14, 2011 at 5:43 PM, Doug Calvert
wrote:
>>> ridiculously high performance out of the tiny little box... rivaling the
>>> best cesium references made for under $200.
>
> Far and away better than the M12+ or M12M?
The Oncore GPS recievers are only GPS recievers that is only 1/3rd of
>> As far as Lady Heather not working with other GPSDO's... well, She has
>> good taste. The Trimble Thunderbolt is far and away the best time-nut GPSDO
>> out there. It is highly configurable and controllable, comes with a very
>> good OCXO, and is dirt stinkin' cheap. If you dot all your i
I was speaking in terms of the user. The point I was trying to make is that
if the user had a map, chart or simply a set of three dimensional
coordinates created from one datum, then that user had better use the same
datum or position errors will be evident. The Z direction is typically used
by nav
Michael,
On 14/09/11 17:05, Michael Perrett wrote:
The user, mostly military or marine, would choose the datum he/she wanted to
use. This would match up the local map with the GPS derived position. The
difference could be quite large (hundreds of feet), especially important in
the Z (vertical) d
>From a friend:
=
> Any guess as to how accurate these are?
1. They vary. You have to look up the info on the particular benchmark.
Some benchmarks and geodetic monuments (see below) receive a lot of
attention and are known as "First Order" points. Many more receive less
attention and are
> I hear that there is a hobby where people photograph these and collect
> the photos. Seems pointless in the city but many are on mountain
> peaks and other places with good views. The hobby is more reasonable
> if you find them without using GPS. The USGS maps are good enough o
> put you withi
Discussion of precise time and frequency measurement" <
> time-nuts@febo.com>
> Subject: Re: [time-nuts] Averaging Location for Position Hold
>
> 2011/9/13 Miguel Gonçalves :
>>
>>> Hi all!
>>>
>>> I am installing a timing GPS unit over a new location
On Tue, Sep 13, 2011 at 11:22 PM, Don Latham wrote:
> Just looked up all USGS maintained benchmarks within 30 mi radius of my
> home. One, at about 1.7 mi is a class A. the search site is
> http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl
> Took me less than 5 min to find it via Google.
> Don
The US
http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl
is what I use. Best to check them out on google maps or earth to see
what you are getting into. Some have a summary of how to get to the marker.
I use one in a road, but it is a dead end. If it says satellite
viewable, it will be a large X.
n37 48
> Often, you can talk to the local city/county and find out where some
> accurate benchmarks are, typically on a curb. They are used to define
> street positions and such.
I'm in Menlo Park. The USGS has a big office complex here. That includes a
bench mark just outside the front door of the
Just looked up all USGS maintained benchmarks within 30 mi radius of my
home. One, at about 1.7 mi is a class A. the search site is
http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl
Took me less than 5 min to find it via Google.
Don
Jim Lux
> On 9/13/11 4:24 PM, li...@lazygranch.com wrote:
>> I think
Hi!
On 14 September 2011 05:36, Mark Sims wrote:
>
> Lady Heather's precision (nominal 48 hour) survey collects data over
> multiple 1 hour periods. With 48 hours of data, multipath and transient
> disturbances are minimized. It applies weighted median filters to the data
> and does other st
Any local surveyor or civil engineering firm will know where the
benchmarks are.
Also see:
http://www.ngs.noaa.gov/cgi-bin/datasheet.prl
Don
Jim Lux
> On 9/13/11 4:24 PM, li...@lazygranch.com wrote:
>> I think I mentioned this is a thread one before. If you are really
>> interested in position ac
On 9/13/11 4:24 PM, li...@lazygranch.com wrote:
I think I mentioned this is a thread one before. If you are really interested
in position accuracy, you look up a calibrated point from the USGS that you can
safely and legally access, then take a reading. I say safely because many
points are in
Lady Heather's precision (nominal 48 hour) survey collects data over multiple 1
hour periods. With 48 hours of data, multipath and transient disturbances are
minimized. It applies weighted median filters to the data and does other
statistical analysis to arrive at a final location. With a
Much of the serial interface protocol used by these disciplined oscillators is
standard. I plugged my Symetricom into Lady Heather and most features worked.
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Upon further investigation I learned that Lady Heather is only for Trimble
units...
I could borrow a Windows laptop from my company for a couple of days. That's
how I surveyed my window (current location of the GPS antenna) using SynTac
(formerly WinOnCore).
Cheers,
Miguel
On 14 September 2011 0
Your milage can vary significantly with use of antenna and receiver. Dualfreq
chokering and carrierphase shifts the degree significantly.
Cheers,
Magnus
Miguel Gonçalves skrev:
On 13/09/2011, at 23:10, gary wrote:
> Google maps/earth is sometimes on the money, and sometimes not. Remember
2011/9/13 Miguel Gonçalves :
>> I guess the other question is what do you get with Lady Heather? That is,
>> how does it average your position?
>
> I will try it over this weekend. I have to get a Windows PC. Only Macs and
> FreeBSD boxes here.
I thought Lady Heather. If so do you really have
On 13/09/2011, at 23:10, gary wrote:
> Google maps/earth is sometimes on the money, and sometimes not. Remember,
> these are orthorectified images pieced together. That can't be easy. [They
> are also on my fecal matter list since they trespassed on my land
> (undeveloped) to place a satelli
I think I mentioned this is a thread one before. If you are really interested
in position accuracy, you look up a calibrated point from the USGS that you can
safely and legally access, then take a reading. I say safely because many
points are in the middle of the street. Legally means no trespas
time, unless compensated for the propagation delay.
John WA4WDL
--
From: "Rex Moncur"
Sent: Tuesday, September 13, 2011 6:28 PM
To: "'Discussion of precise time and frequency measurement'"
Subject: Re: [tim
Hi All
In my case the Google Earth position cf if the GPS averaged position is
within 3 metres of the physical position of my GPS RX but about 8 metres
from the physical position of my GPS antenna. Can anyone tell me if the
length of the cable has any affect on the GPS reported position or is the
On 9/13/11 3:10 PM, gary wrote:
since they trespassed on my
land (undeveloped) to place a satellite cross mark for a shoot. Needless
to say I was pissed to see the big X on google earth, though now I have
free pointers for NEWS. The while paper had mostly rotted away.]
tangential to time nuts
On Tue, Sep 13, 2011 at 2:23 PM, jmfranke wrote:
> I believe that should read WGS 84 not WPS84.
Yes. G and P key are not even close.Put after writing this I'm
wondering how old the UT+ is. WGS84 must have been created in '84.
Chris Albertson
Redondo Beach, California
_
Google maps/earth is sometimes on the money, and sometimes not.
Remember, these are orthorectified images pieced together. That can't be
easy. [They are also on my fecal matter list since they trespassed on my
land (undeveloped) to place a satellite cross mark for a shoot. Needless
to say I was
Hi David!
Same here.
I discussed this matter with a friend that did some GIS work a few years
back and we both believe that the unit reporting the wrong position might be
doing this because it's only seeing half of the sky (it is near a window
facing SE) while the other one sees the entire sky.
Hi Chris!
The problem with auto-survey is that it doesn't report the averaged position
in the log file. I haven't checked if the binary protocol enables access to
this but if it does it's just a matter of patching the driver IMHO. If I use
auto-survey should I continue using mode 1 in ntp.oncore?
Thanks!
I believe then that is best to rely on SynTac position averaging or the
auto-survey feature?
Regards,
Miguel
On 13 September 2011 20:24, Poul-Henning Kamp wrote:
> In message p+kegb...@mail.gmail.com>
> , =?ISO-8859-1?Q?Miguel_Gon=E7alves?= writes:
>
> >I have a log with around 213400
>
>
>
> Also, can you really trust Google Earth as an authoritative source?
> I'm not sure.An interesting test would be to go find a USGS
> benchmark or a section marker near you then enter it's location into
> Google. See if Google hits the marker.
> --
>
>
>
> For what it's worth, my Thunder
Also, can you really trust Google Earth as an authoritative source?
I'm not sure.An interesting test would be to go find a USGS
benchmark or a section marker near you then enter it's location into
Google. See if Google hits the marker.
--
For what it's worth, my Thunderbolts here did a 4
I believe that should read WGS 84 not WPS84.
John WA4WDL
--
From: "Chris Albertson"
Sent: Tuesday, September 13, 2011 5:03 PM
To: "Discussion of precise time and frequency measurement"
Subject: Re: [time-nuts] Averaging L
2011/9/13 Miguel Gonçalves :
> Hi all!
>
> I am installing a timing GPS unit over a new location where I already have a
> NMEA GPS with PPS (let's call it unit A). The NMEA GPS is logging every 16
> seconds its GPGGA string.
The Oncore UT+ can does it's own site survey automatically. That's
the b
In message
, =?ISO-8859-1?Q?Miguel_Gon=E7alves?= writes:
>I have a log with around 213400 samples. Each line is similar to this one
>[...]
>I averaged the minutes of latitude and longitude, the MSL (278.9) and the
>Geoid Separation (51.2) and got the following
That doesn't work very well, becaus
Hi all!
I am installing a timing GPS unit over a new location where I already have a
NMEA GPS with PPS (let's call it unit A). The NMEA GPS is logging every 16
seconds its GPGGA string.
I have a log with around 213400 samples. Each line is similar to this one
55817 48494.500 127.127.20.0
$GPGGA,
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