[FOSS-GPS] RTKLIB Vehicle Accuracy

Tue Jul 1 13:16:33 PDT 2014

Hi Nick

No for the base I use the Leica GG02 L1/L2 and only use the LEA6 T on the
roving units
I will save a plot and send it to you to show you the results I get.

What coax to you use? I normally use either LMR 400 where I can use TNC
connectors and 173 where I use SMA but then not longer than 10 cm of 173.

I have had a situation where have a Leica SR 500 base and a AT504 antenna
where we used 23 meters of RG58, we had lots of problems with the base. I
changed the coax to LMR 400 and did not have any problems after the change

Regards

Anton

On Tue, Jul 1, 2014 at 10:07 PM, Nick Østergaard <oe.nick at gmail.com> wrote:

> Ok, interresting. Is is working with the patch on both rover and base?
> I have tried with a setup, but I had had very bad results, especially
> when I moved. Attached is results I have had, and that with antennas
> as [1] with bias voltage on and half a meter of coax. The signal is
> great as far as I remember. I have LEA6T's also (maybe 4T), although I
> don't quite remember exactly, it is quite some time ago since I tried.
>
> Attached is a post processed result.
>
> [1]
> http://dk.rs-online.com/web/p/smt-antenner/7239151/?searchTerm=SM-1575&relevancy-data=636F3D3226696E3D4931384E4B6E6F776E41734D504E266C753D6461266D6D3D6D61746368616C6C7061727469616C26706D3D5E5B5C707B4C7D5C707B4E647D2D2C2F255C2E5D2B2426706F3D313326736E3D592673743D4D414E5F504152545F4E554D4245522677633D424F5448267573743D534D2D3135373526
>
> 2014-07-01 21:38 GMT+02:00 Anton Strydom <agstrydom at gmail.com>:
> > Hi Nick
> >
> > Yes I get a reasonable plot using that specific unit. However for what we
> > intend doing in the long term we will be using a different design helical
> > antenna that we are in the process of developing.
> >
> > The units in the photographs are only for testing and setting up but we
> get
> > good results. For communication we use cellular routers connected to
> Leica
> > GGO2 L1/L2 base or else we use 3D Robotics XBEE radios. On the roving
> unit I
> > use an ARM processor where I have 4 rs232 ports available. It works very
> > well and is very stable.
> >
> > The radios I use where i have no cellular coverage.
> >
> > Attached is a photograph of  the base setup
> >
> > Regards
> >
> > Anton
> >
> >
> > On Tue, Jul 1, 2014 at 9:27 PM, Nick Østergaard <oe.nick at gmail.com>
> wrote:
> >>
> >> Hi Anton
> >>
> >> Really? You get by with that small patch antenna? Is that a good (green
> in
> >> rtkplot) RTK solution you get from that constant?
> >>
> >> Regards
> >> Another Nick
> >>
> >> Den 01/07/2014 21.11 skrev "Anton Strydom" <agstrydom at gmail.com>:
> >>
> >>> Hi Nick
> >>>
> >>> I have done a lot of testing with U-Blox LEA 6T at speeds of up to 120
> km
> >>> / h. Lat & Lon does not appear to be a problem but elevation is a
> problem. I
> >>> paid the equivalent of $60 for the 2 receivers and ceramic patch
> antennas.
> >>>
> >>> They are accurate on base line up to 10km where after accuracy
> >>> drastically degrades.
> >>>
> >>> I do all my testing in real time and do not post process.
> >>>
> >>> If you want to I can speak to my supplier and see if they still have
> some
> >>> of the LEA 6T's in stock at the price I paid for them.
> >>>
> >>> Attached are photographs of the units I am using
> >>>
> >>> Regards
> >>>
> >>> Anton
> >>>
> >>>
> >>> On Tue, Jul 1, 2014 at 8:50 PM, Danny Miller <dannym at austin.rr.com>
> >>> wrote:
> >>>>
> >>>> It does work in moving.  But signal problems do still make the
> position
> >>>> jump around, trees and buildings and an antenna's orientation
> changing can
> >>>> make an error happen.  Antenna quality has a lot to do with that, too.
> >>>>
> >>>> RTKLib requires a GPS with RAW pseudorange outputs.  The NV08C is a
> >>>> good, cheap one to do it:
> >>>>
> >>>> http://www.nvs-gnss.com/contacts.html
> >>>>
> >>>> Contact your local sales rep there- it was actually easy in my
> >>>> experience to order a couple from them, and oddly cheaper than Newark
> >>>> element 14, as well as quicker to ship.
> >>>>
> >>>> Danny
> >>>>
> >>>>
> >>>> On 7/1/2014 1:24 PM, Nick wrote:
> >>>>
> >>>> Hello,
> >>>>
> >>>> I am interested in getting an RTK GPS setup working for a moving
> >>>> vehicle, not fast, perhaps 10 mph. I would postprocess the data
> collected
> >>>> later, using data downloaded from a nearby station.
> >>>>
> >>>> My desire is to log elevation data every few seconds as the vehicle
> >>>> drives. I hope to achieve 10-20 cm accuracy for the position and the
> >>>> elevation.
> >>>>
> >>>> As I research RTKLIB, it seems like most information I come across is
> >>>> regarding a static location. Is my goal feasible to achieve this kind
> of
> >>>> accuracy as the vehicle moves?
> >>>>
> >>>> If so, can anyone recommend a good board to get me started? I'm hoping
> >>>> to be able to do this for under $200 (just one receiver since the base
> >>>> station is public) -- please give me a reality check if this is
> unlikely.
> >>>> Thanks,
> >>>>
> >>>> Nick
> >>>>
> >>>>
> >>>>
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