How to "stay" in Fix RTK mode with NS-HP-GL

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madsdyd
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Joined: Tue Apr 24, 2018 1:57 am
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How to "stay" in Fix RTK mode with NS-HP-GL

Postby madsdyd » Wed Apr 25, 2018 2:38 am

Hi there

New user.

I am trying out the base+rover combo with a NS-HP-GL as base (survey, 60 seconds) and a NS-HP-GL (5Hz) as rover.

Simple setup, like userguide.

When I start the "rover" after the base have settled, it is completely random how quickly it goes into Fix RTK. Sometimes it takes minutes, other times it takes seconds. And, even when it has settled in RTK Fix quickly (10 seconds or so), and is using 13-14 sattelittes, moving the rover just 30 cm, will make it go into Float RTK, where it will often stay for a very, very long time, say 10-20 minuttes.

And, moving my rover 30 cm, then moving back, will more often than not, make it "stay" in something about 30 cm away, and up to a meter above the position that was initially fixed (and it is now back in).

What can I do to "stay" in Fix RTK mode? Or, improve the fix time? Hints? Configuration options? Note: I have 13-14 sattelittes with +37dB or more that is utilized...

My end application is a vehicle that will move max 2 m/s - but I really need very precise measurements; its a survey rover. Especially altitude.

Any help appreciated.

Kind regards

Mads

MOUSE and CAT
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Joined: Thu Feb 15, 2018 10:04 am
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Re: How to "stay" in Fix RTK mode with NS-HP-GL

Postby MOUSE and CAT » Wed Apr 25, 2018 9:28 am

Hi , which antena you are using for system ?

madsdyd
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Joined: Tue Apr 24, 2018 1:57 am
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Re: How to "stay" in Fix RTK mode with NS-HP-GL

Postby madsdyd » Wed Apr 25, 2018 5:05 pm

MOUSE and CAT wrote:Hi , which antena you are using for system ?


I am using this http://navspark.mybigcommerce.com/tri-b ... e-antenna/ - should be ok, not?

Kind regards

MOUSE and CAT
Posts: 29
Joined: Thu Feb 15, 2018 10:04 am
Contact:

Re: How to "stay" in Fix RTK mode with NS-HP-GL

Postby MOUSE and CAT » Thu Apr 26, 2018 3:25 am

Hi,I think your Triband antena is good enough. :)
So in my experience use NS-HP-BD to keep FIX RTK run for for lonng time, You need to make sure everything is not interrupted :
Signal quality >= 38db , dont touch or put anything above antena.
You can improve signal by put antena on a iron ground plane .
Number of satellites > 9
if these conditions above is good, you need think about RTCM data :
RTK Age (lag) :  the lag delay in received base data in wireless transmit.
Loss some RTCM data : usually causes FLOAT RTK (no drop to DGPS but cannot jump to FIX).

madsdyd
Posts: 8
Joined: Tue Apr 24, 2018 1:57 am
Contact:

Re: How to "stay" in Fix RTK mode with NS-HP-GL

Postby madsdyd » Thu Apr 26, 2018 3:06 pm

MOUSE and CAT wrote:Hi,I think your Triband antena is good enough. :)
So in my experience use NS-HP-BD to keep FIX RTK run for for lonng time, You need to make sure everything is not interrupted :
Signal quality >= 38db , dont touch or put anything above antena.
You can improve signal by put antena on a iron ground plane .
Number of satellites > 9
if these conditions above is good, you need think about RTCM data :
RTK Age (lag) :  the lag delay in received base data in wireless transmit.
Loss some RTCM data : usually causes FLOAT RTK (no drop to DGPS but cannot jump to FIX).


Don't touch or put anything above antenna: I may try that :-).
Could you elaborate on the ground plane? Size, material, does it need to be connected to ground of my curcit? Final setup is a rover that needs to be as light as possible...

RTCM: The setup is stationary right now, with a direct (wire) connection from the base to the rover. It is set for 56700 baud, and the "raw" mode (I think it is called) is used - that is, not the RTCM mode. I do not see any age above say 1 or 2 in GNSSViewer...

Kind regards

Mads

MOUSE and CAT
Posts: 29
Joined: Thu Feb 15, 2018 10:04 am
Contact:

Re: How to "stay" in Fix RTK mode with NS-HP-GL

Postby MOUSE and CAT » Thu Apr 26, 2018 8:53 pm

You can google "ground plane rtk antenna" to refer. We have some result:
http://gpspp.sakura.ne.jp/anteva/anteva.htm
https://docs.emlid.com/reach/antenna-placement/
So , just put antenna on iron plane as you see.
RTK Age can find in tab "RTK info" on GNSSViewer , here is a capture on old version:
nshp.png
nshp.png (249.11 KiB) Viewed 1264 times

Have nice day.


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