Curious ashtech dat...
 
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Curious ashtech data set

cadastrephy
(@cadastrephy)
FNG Member

I have been using VRS for project location for some years. I need to set up a control network for the Highway Department using a static network. I dug out the old Ashstech Extremes to set up the network. When I downloaded the files, both the almanac and datasets were dated 02.107 instead of 21.333.  I was always under the impression that the receivers got their time stamp from the GPS signals.

When I dump them in a project, they appear reasonable relative to each other. None were on a known point, and the crew didn't VRS any because I was going to send them to OPUS before I solved the net. OPUS rejected them because they were 50 km outside the nearest polygon. I am surrounded bu CORS sites. I thought it might be a labeling error and tried just changing the date tags, but that didn't work. I have done a lot of searching for a common occurance or explanation, but found nothing out there. There is no documentation in my Ashtech literature suggesting an internal clock.

Any Ideas out there?

Thanks

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Topic starter Posted : December 5, 2021 8:46 pm
Jim Frame
(@jim-frame)
5,000+ posts Member

It sounds like a GPS week rollover problem, in which the firmware incorrectly interpreted the date coming from the SVs.  You may be able to fix your files by converting to RINEX and then using a text editor to find-and-replace the bad dates with the right one.  Re-submit to OPUS to check.

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Posted : December 5, 2021 9:23 pm
Larry Scott
(@larry-scott)
500+ posts Member

my Z12 revivers report date (gps week number) 1024 weeks behind. So, convert to rinex and you can edit the date with search and replace. Teqc also has week rollover correction tools. But I just use TextPad.

and there is a firmware fix for ZExtreme and ZSurveyor. So my ZSurveyor work like new. And my z12 work great too, but I have to edit the date. The time is accurate but 1024 weeks off. After date edit opus, and any other software accepting rinex, work just fine with old reliable Z-XII. The updated ZSurveyor is completely compliant. 

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Posted : December 6, 2021 12:08 pm
Loyal liked

Larry Scott
(@larry-scott)
500+ posts Member

Here’s ZExtreme week rollover fixed firmware from member: robots. If you have the cable and receiver upload software, I’ve used this firmware successfully. Beware if you’re unfamiliar with firmware flash you could accidentally brick the receivers. 
https://github.com/robots/survey_gps/tree/master/ashtech

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Posted : December 6, 2021 12:17 pm
Larry Scott
(@larry-scott)
500+ posts Member

And if you’re looking to sell it, let me know. It’s in my workflow. 

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Posted : December 7, 2021 12:26 pm
OleManRiver
(@olemanriver)
10+ posts Member

Ashtech z12 we’re bulletproof. Great receivers for static work. I used them in USMC . One issue with older receivers is the firmware issue for gps role over.   But the biggest issue to watch for is that gps messaging and ICD-xx compliance could bite you in the but.  So while converting to RINEX and editing the dates will work. Just make sure you set up an independent check on that control.  I loved those old receivers.  I literally watched one slide down the tarmac behind a jet well in the opposite direction of the jet when he taxied out on the runway while I was collecting data. It melted the antenna and box and cables.  But the receiver still worked. 

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Posted : December 8, 2021 5:51 pm

Larry Scott
(@larry-scott)
500+ posts Member

@olemanriver I have 2 Z-XII with matching whopper geodetic antenna. They ARE bullet proof. And 2 ZSurveyor with geodetic antenna. (Easily $100K for the 4 in 1999)

Without a doubt the Z-XII is a workhorse. Except for week rollover, they perform as well today as when delivered in ‘97 or ‘98. 

Updating the ZSurveyors’ week rollover firmware and again: zero degradation in performance. Obsolete? Perhaps. Worn out? NO  and I got the lot for near zero $. And I have new CMOS batteries too. And the new gen sats are legacy compatible. I’m set for long time yet. Windows 10 too!!

 

This post was modified 2 months ago 2 times by Larry Scott
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Posted : December 8, 2021 6:41 pm
Brad Ott
(@brad-ott)
5,000+ posts Supporter
Posted by: @larry-scott

(Easily $100K for the 4 in 1999)

Boy, howdy!  Do we ever take that stuff for granted these days!?!

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Posted : December 9, 2021 7:23 am
OleManRiver
(@olemanriver)
10+ posts Member

@larry-scott  yes I wish I had a dollar for all the PACS and SACS I observed and set with those. I should kick myself for never getting licensed.  Surveying since the 90’s metes and bounds PLSS and geodetic work all over the world.  But I am studying now and trying to learn this degnabit hp35s. I would buy or borrow a z12 and get me a robot.  Set up the z12 while I run out the boundary and send to OPUS.  Two points and call it a day.  So simple to run. I ran the Trimble 4000ssi and ssi mgrs units also. Needed to lay attention on those so you didn’t observe the wrong message types.  They did have the fast static modes which were nice.  Any one run the first intergraded  rover receiver the old Trimble 4800’s. TSC1. Battery screwd onto the pole.  The good old days. 

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Posted : December 9, 2021 2:21 pm

Larry Scott
(@larry-scott)
500+ posts Member

@olemanriver I cut my teeth on 4000SL, 5 channel, L1, only baseline processing on a 286 with a mathco. Downloaded to 5 in floppies. 4-5 observation windows; winter at night daytime in summer. And happy to do it. SST was the first upgrade. 
I’m quite happy with Z-XII as-is.

I’m not in a high production workflow. and I baseline process, and of course OPUS. OPUS is a great thing. 

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Posted : December 9, 2021 2:35 pm
Gary liked
Larry Scott
(@larry-scott)
500+ posts Member

@olemanriver Funny thing. Back in the Trimble SL/SST/SSI days, Trimble and Ashtech was the classic feud. Today however the siftware for Ashtech is GNSS and DOWNLOAD32. In the ‘about’ they are copyright Trimble.  

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Posted : December 10, 2021 10:25 pm
OleManRiver
(@olemanriver)
10+ posts Member

@larry-scott Yes for sure .  Charlie Trimble and Mr Ashtech parted ways as they could no longer agree.  Both genius in their own rights.  Man how things have changed.  We live in a throw away society now days.  I was still running a T-3 by wild in 2000-2005 because some total stations could not handle 138 degree F.  So I turned a many of angles with those.  They lasted for ever.  Now we have total stations and robots that technology changes so fast they become obsolete.  I love the robot. But i miss grabbing just a regular old total station to set up spin a angle and distance. Buck in or wiggle in on a line without having to create some job in some barney rubble ciphering box data collector.  

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Posted : December 11, 2021 8:04 am

Larry Scott
(@larry-scott)
500+ posts Member

@olemanriver Mr Ashtech aka Javad Ashjaee.

I still use my T3 and T2 and HP3805 quite a bit. Along with Z-XII. And I got hold of these lovely reflectors by Wild for cheap. And a Mils T2 is still unbeatable  

 

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Posted : December 11, 2021 8:29 am
OleManRiver
(@olemanriver)
10+ posts Member

@larry-scott  I don’t think I can see good enough up close to read the scales anymore.   😂. Nice set up for sure.  As i have fell back into surveying this past year. I miss working out west. See for miles here i. The east not very far. But I have been lucky to walk behind some early 1900’s and prior surveys. I could do those for free just because so fun and you have to actually think when retracing them. No rebar no pipes to find with a mag locator. Just walk in The surveyors footsteps . I reckon a good compass and good pacing ability is the most important equipment on the job.  But everyone has to get out there robots traverse and stake out pre calced points to search for things that they can’t find.  Mag locator doesnt find blazed trees or wood stake.  Or creeks or old fire breaks etc.   old road beds.  These our the reasons I am trying to study to take the fs ps exams and i am knocking on the door of 50.  I love this work.  I enjoyed all the gps triangulation shooting polaris and sun shots. But nothing challenges one like old boundary surveys.

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Posted : December 11, 2021 8:51 am
Brad Ott
(@brad-ott)
5,000+ posts Supporter

@larry-scott that is some sexy survey porn.

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Posted : December 11, 2021 9:46 am

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