Activity Feed › Discussion Forums › GNSS & Geodesy › BRx7 vs. Javad
Are you referring to taking multiple shots and averaging them in the field? I began doing this a little while back, all the other crews typically just take 2 shots and inverse them…when I realized I could just average them I didn’t understand why we wouldn’t do that. Sometimes if the canopy is bad and numbers don’t look great I will shoot 4 or 5 30-60 second shots all the same point number (with weighted average) and lose my lock at least a couple of times in between. I did this with fieldgenius and magnet field on the Sokkia grx2 and just the other day with the newly handed down to me Trimble R10 and tsc3.
What do you use when you actually need to tie in a building corner and not just something you can lean the GPS up against? I assume you do have a TS but I don’t think I’ve ever seen you mention it.
- Posted by: @350rocketmike
Are you referring to taking multiple shots and averaging them in the field? I began doing this a little while back, all the other crews typically just take 2 shots and inverse them…when I realized I could just average them I didn’t understand why we wouldn’t do that.
Especially considering you get the deltas and standard deviations from the weighted average right there on your screen without having to back out, go into COGO functions, pick points, and inverse….and if you really want you can remove a solution/observation from that average afterward.
Office folks do it too, drives me nuts.
“I want to inverse between all the check shots.”
“You don’t need to inverse, just run a point derivation report and it will show you every single check shot and how they compare in a single table, with anything that fails tolerances flagged in red.”
“So I can’t inverse?”
“You can inverse. But you have a tool that gives you the same, plus more, information faster. If you want to split up all those check shots into separate points and spend ten minutes picking each individual one for inversing, go for it.”
“…OK, I’m going to split them up and inverse. And then complain about the software.”
“…people will come to love their oppression, to adore the technologies that undo their capacities to think.” -Neil Postman I don’t now anything about the Javad systems but like “bama7x57” I also use the Hemisphere S631 units. Coverage while using network corrections can be hit and miss, but when using the base / rover setup, these things get the job done. Once learned, the Field Genius Software to run the S631’s is actually very good. The Hemisphere S631 is the basically the same as the BRX7 except that the BRX7 is opened up to run Carlson survey software. I am very happy with my GNSS units.
Remember, theses are survey tools only, It is the responsibility of the surveyor to use them correctly. as an old mentor once told me “There’s no substitute for knowing what you’re doing”
So far nobody in our office has complained. It’s all in the raw data so they can see how well the shots fit with each other.
- Posted by: @350rocketmike
What do you use when you actually need to tie in a building corner
For what I do, out in the country +/- 0.1??~ish, I just stand back away from the building corner and eyeball myself on line with the building faces then fillet in CAD later. Multiple independent checks have proven this method for my needs. But, yes, if we are doing a building addition, then out comes the TS (robot) with shots on the existing foundation, often with offsets of some kind as well, but much smaller if any eyeballing.
We use rtk in the woods at times but am skeptical about fixed solutions in difficult areas. We sometimes run a static session and post process but with so many cycle slips I wonder about ‘claimed’ accuracy of some rtk points . Perhaps a field shootout with these instruments could help settle the differences.
- Posted by: @350rocketmike
What do you use when you actually need to tie in a building corner and not just something you can lean the GPS up against? I assume you do have a TS but I don’t think I’ve ever seen you mention it.
I mostly just shoot roof corners.
I I need a bldg Cor proper, I often just put for the shot desc:450 os 2′ n se Cor mtl bldg
451 os 2?? n sw Cor mtl bldg
452 os 2′ s nw Cor mtl bldg
453 os 2′ s be Cor mtl bldg
and, add a sketch for details. Take a pic of those details with the LS and it??s in the file.
- Posted by: @hpalmer
We use rtk in the woods at times but am skeptical about fixed solutions in difficult areas
That is where Javad shines.
the FACT that non Javad users keep saying stuff like ??must use total station? etc. tends to tell me they are not yet able to do what Javad does. But, that??s just my view on their comments.
I come in from the field with part of my day still left quite often. That means I have run out of field work, before I have run out of daylight.
I retrace a number of surveyors who TRY to push their gps like a Javad. And, I frequently find errors of the 3?? to 6?? variety.
So, I appreciate the skepticism. I??d prefer that all surveyors were more skeptical, and less optimistic. Especially on this subject.
Stay skeptical.
???
Nateps. ALWAYS run gps with skepticism.
- Posted by: @leegreen
Not yet. But they are working on it, Csrlson is working on a similar feature for RTK adjustment in the field. Stay tuned.
RTPK is not “RTK Adjustment” application. Are you sure that Carlson is working on real time post-processing of raw data between the base and rover? This is what RTPK does. Raw data is collected by the rover and raw data is captured from the RTCM correction stream, then processed on a user defined periodic basis (usually between 30-120 seconds) during an observation. Before the user stops collecting data, he knows that he has collected enough raw data for a good solution. (Remember all those static observations when you would collect more raw data than you thought you would need to hopefully prevent a return trip?) He can even see if several iterations agree with each other and if those post-processed results agree with the RTK solution. Perhaps Carlson is working on this too, but it’s a complex task. To my knowledge no one else has this feature.
They are working something similar. Also I never mentioned “Carlson”. You implied that. Lol.
@leegreen No, I guess you didn’t say “Carlson” you said “Csrlson”. Check your quote.
@shawn-billings Yes, that’s correct. Lol
Regardless of the minutae of who said exactly what isn’t it great that others manufacturers are providing more options!
Absolutely. Competition for market share benefits the consumer in both innovation and reduced product costs.
The best just keep getting better.
- Posted by: @350rocketmike
Are you referring to taking multiple shots and averaging them in the field? I began doing this a little while back, all the other crews typically just take 2 shots and inverse them…when I realized I could just average them I didn’t understand why we wouldn’t do that. Sometimes if the canopy is bad and numbers don’t look great I will shoot 4 or 5 30-60 second shots all the same point number (with weighted average) and lose my lock at least a couple of times in between. I did this with fieldgenius and magnet field on the Sokkia grx2 and just the other day with the newly handed down to me Trimble R10 and tsc3.
In SurvCE after you have averaged the shots, it’s a bit of a PITA to reproject things (ie. to a new coordinate system, localization, etc.). I typically do it back in the office using the Starnet cluster features, but I can see the advantage to using it if you never plan on reprojecting or if it’s on an established site.
The few rural sites I go to are just for construction and there is usually a lot of extra room in the setbacks. A traverse for me is usually just 4 or 5 setups around an existing house and when I close out it’s always less than 0.010 so no real reason for the office to adjust anything. Hopefully I’m correct in assuming that under these circumstances I might as well average any GPS shots on control or bars myself?
- Posted by: @hpalmer
Perhaps a field shootout with these instruments could help settle the differences.
There was a shootout between Javad and Trimble a few years ago. Everyone that went had a good time and learned a bunch, and since they shared their results here, those of us that didn’t go benefitted too. The state of the art has advanced considerably since 2017. It’s only been 5 years but there are more constellations available and Javad, Trimble, Carlson, and others have evolved to take advantage of them. RTPK wasn’t a thing back then. I propose that Round Two be held this summer when the leaves are on.
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