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False fixes  


Mapper6683
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(@rotatenorth)
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Is it the DC software or the Unit? We have been seeing more and more issues with point staking points since we ungraded our units and dc. I’m less than thrilled with the sloppiness and extra time it’s taken to fix. 

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Nate The Surveyor
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In the afternoon, sat configuration has been poor. 

It'll improve in the fall...

Or

Get a newer gps that uses "all birds up". Galileo, bideu, and such.

N

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Rover83
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Posted by: @nate-the-surveyor

Get a newer gps that uses "all birds up". Galileo, bideu, and such.

Another option is to get a setup that does not use fixed/float solutions.

A bad fix, in my experience, comes more often from poor observation conditions (canopy, high multipath) than the number of birds in the sky. Still, it should be rare with most modern receivers.

What gear model/year are you using?

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Mapper6683
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@rover83 Hiper Vr and FC 5000 with magnet 

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Plumb Bill
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@rotatenorth

Someone told me this about five years ago"

Leica:  Hardly any bad fixes, but fixes in fewer places

Trimble:  A few bad fixes, but fixes in far more places

Topcon:  A LOT of bad fixes, but fixes the most places

I have definitely seen this ring true with respect to Leica/Trimble - haven't used Topcon.  I've followed GNSS development very closely over the past 20 years or so.  Correct me if I'm wrong, but I don't think Topcon has really developed their line much in the past 10 years?  Not throwing shade at them, it just feels like they were more content to play in the machine control sandbox and develop less for land surveyors.

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lukenz
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@plumb-bill

Have to agree about the Trimble/Leica assessment above but need to be comparing gear of a similar age (i.e. not R12 vs system 1200 etc.)

 

One exception is network rtk, have had height fixes with Leica receiver on Leica network where got fixes over half hour apart on benchmark where Heights differed by 0.1m but CQ s said they were normal. Put it down to network bases being over two sides of range of hills and not great geometry to model atmospheric conditions or some processing gremlin/comms interruption. NEVER have this issue with base/rover

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Plumb Bill
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@lukenz

totally agree.  

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Mapper6683
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@plumb-bill well I can speak for the Topcon false fixes. It’s often unfortunately. As to our SP 80s they seem to lock on and be true 98% of the time 

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Plumb Bill
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@rotatenorth

My comment above was probably more true 10 years ago for Leica and Trimble.  I don't think I've seen or heard of a single bad fix from our R10s (basically the R10 equivalent of the R12 since upgraded) since the upgrade.  They have been working amazingly well in the woods, but there's still the 5-10% that needs the robot depending on terrain, etc.

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MightyMoe
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@rotatenorth

98% of the time they will fix, or 98% of the fixes are good?

Cause that's an awful percentage of bad fixes. 

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X-PAD Ultimate from iGage

Nate The Surveyor
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I'm using Javad. But, I don't get the newer sats, Galileo, beidu etc. So, my units need the upgrade. I haven't done it. I'm told 2 things via the grapevine. 

1.) The units that are upgraded, work well, as long as you take the tin foil hat off of them.

2.) The fundamental algorithms to give it optimum performance, in ALL situations is still being resolved.

Mine are paid for. And, I would like to breathe for a while.

Nate

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dmyhill
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Modern receivers rarely get "bad" fixes.

With Topcons you have a choice of how stringent your fix parameters are.

As always, with 4 sats or 400, if the shot matters, dump the pole and get a new solution and a new check shot. If it really matters, wait 15 minutes and do it again, and if your whole world rides on it, wait a few hours and do it again. That is, and will remain the gold standard.

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