Re: [time-nuts] surplus carrier phase measurement-capable receivers (was Thunderbolt firmware differences)
I wanted to have Heather make a RINEX file that could be submiited to OPUS-GIS to get a more precise antenna location. The Tbolt does not support carrier phase measurements. It does output doppler values.
The code phase (pseudorange) values that it outputs look to be VERY difficult to translate into normal pseudoranges. You need to calculate the satellite positions from the almanac, etc to be able to use them.
OPUS-GIS is still in alpha testing mode. I don't know what observable you need to have it post process the data.
What typically-available surplus receivers do carrier phase
measurements[1]? I'm close to putting up a choke ring antenna I scored
off of the surplus market on the roof -- I don't think the wife is going
to let me build a proper monument in the yard. :-) Hence, I, too,
am interested in getting a precise antenna fix. I 'spose I could hire
a surveyor, but that's cheating.
-ch
[1]. I did enough work w/surplus SuperStar receivers that I convinced
myself I could flash the carrier phase-capable software onto the board,
but that's stealing. I am interested in receivers where I can get
legitimate access to carrier phase measurements.
christopher hoover wrote:
I wanted to have Heather make a RINEX file that could be submiited to
OPUS-GIS to get a more precise antenna location. The Tbolt does not
support carrier phase measurements. It does output doppler values.
The code phase (pseudorange) values that it outputs look to be VERY
difficult to translate into normal pseudoranges. You need to
calculate the satellite positions from the almanac, etc to be able to
use them.
OPUS-GIS is still in alpha testing mode. I don't know what observable
you need to have it post process the data.
What typically-available surplus receivers do carrier phase
measurements[1]? I'm close to putting up a choke ring antenna I scored
off of the surplus market on the roof -- I don't think the wife is going
to let me build a proper monument in the yard. :-) Hence, I, too,
am interested in getting a precise antenna fix. I 'spose I could hire
a surveyor, but that's cheating.
Considering that the monument should go clear of the house for the
antennas sky-view, I am sure that you are in good company with most of
us here and many nodes of reference station networks in using the
existing building rather than a fundament.
-ch
[1]. I did enough work w/surplus SuperStar receivers that I convinced
myself I could flash the carrier phase-capable software onto the board,
but that's stealing. I am interested in receivers where I can get
legitimate access to carrier phase measurements.
It depends, what if there is no commecial service available to get the
carrier-phase option?
There have been some work to build up a open-source code-base for GPS
receiver software.
But to answer the question, the CMC/Novatel series OEM boards, Motorola
and Ashtech receivers can all have carrier phase ability. However, the
carrier phase capable receivers is not easy to find.
Cheers,
Magnus
What typically-available surplus receivers do carrier phase
measurements[1]? I'm close to putting up a choke ring antenna I scored
off of the surplus market on the roof -- I don't think the wife is going
to let me build a proper monument in the yard. :-) Hence, I, too,
am interested in getting a precise antenna fix. I 'spose I could hire
a surveyor, but that's cheating.
-ch
Somewhat dated... but since we are looking at surplus...
http://home-2.worldonline.nl/~samsvl/oemtable.htm
I once did get phase measurements out of a Garmin GPSMAP76 with this
http://home.comcast.net/~dmilbert/softs/garbin.htm
Do not know the status of more current Garmin receivers.
Teqc's list of supported format will give you further information.
http://facility.unavco.org/software/teqc/tutorial.html#sec_15
Helenav sells converters for many L1 only phase capable receivers.
http://www.helenav.nl/
To sum it up. Many (most?) surplus receivers are capable of phase
measurements. You have to look out for "crippled" versions, where phase
output might be an software option not loaded into the particular receiver
you find.
[1]. I did enough work w/surplus SuperStar receivers that I convinced
myself I could flash the carrier phase-capable software onto the board,
but that's stealing. I am interested in receivers where I can get
legitimate access to carrier phase measurements.
The superstar family is actually quit good at phase measurement. As you
have noted not all receivers have the correct options loaded to enable
phase output.
With Novatel having EOLed the SuperStarII last year(?), the old CMC
receivers are all out "in the cold". I think though that you could still
contact either Novatel or CMC Electroncs to order the software option for
your SuperStar receivers.
There are also higher end receiver appearing in the surplus market. Both
L1 OEM-cards from Ashtech, Trimble, Novatel, Magnavox and also geodetic
dual frequency receivers from the above and Topcon, Javad, Leica, Sokkia
and some others.
Beware though that old surplus equipment are sometimes priced "higher than
new" on "the bay" and elsewhere.
--
Björn
But to answer the question, the CMC/Novatel series OEM boards, Motorola
and Ashtech receivers can all have carrier phase ability. However, the
carrier phase capable receivers is not easy to find.
The Motorola Oncore VP did have carrier phase output. (with the right
option loaded.) In newer models they removed the phase output.
--
Björn
On 7/13/09 1:59 AM, "bg@lysator.liu.se" bg@lysator.liu.se wrote:
What typically-available surplus receivers do carrier phase
measurements[1]? I'm close to putting up a choke ring antenna I scored
off of the surplus market on the roof -- I don't think the wife is going
to let me build a proper monument in the yard. :-) Hence, I, too,
am interested in getting a precise antenna fix. I 'spose I could hire
a surveyor, but that's cheating.
"hire a surveyor".. Really... This is time-nuts.
You should get yourself a good quality theodolite (surplus, or make one.. If
Tycho Brahe can do it, so can you) and start making those astronomical
measurements yourself. I'll bet there's even astromonical surveying mailing
lists. Procedures wise, the BLM has a manual online (since much of the
survey work for the U.S. Public Lands Survey System (PLSS) is based on
astronomical methods...). A copy of Davis and Foote (or whatever the
current authors are) wouldn't be useless, either.
10cm accuracy is a big challenging with a standard theodolite. You can read
a Wild T2 to a second of arc.. That's on the order of a few tens of meters
position accuracy.. But I think with multiple measurements, one can bring
the uncertainty down. There's a great CDROM available for $50 from the
Institute of Navigation with all the papers on celestial nav