Testing GNSS Engines settings issue

Duane Frymire

Active Member
Hello,
Wondering if someone can take a look at the video in this google drive link. https://drive.google.com/open?id=1e6atrGlPdSK3smKVnNoJdaXfg-vwEsLi

I'm using pre-release version of software and testing the new engines. I haven't had any luck with improved performance using the rtn, so tried using LS as base and LS as rover and took some video of what's happening. It appears the engines are re-setting too quickly, or too often?

I tried all 3 engine setups and only managed 2 fixes under the GPS/Glonass traditional, and these were brief and kept re-setting and coming back. The first (longest) video shows all constellation 6 engines first, then all constellation 2 engines, then traditional at end. A couple short videos showing base, noise levels, and general location. Also a screenshot and printout from planning software showing satelites in view and best constellation at the time.

It's not what I call a very challenging location, although there was some low cloud cover. Wondering if I have something set incorrectly. Using boundary profile so it's looking for 2 engines in agreement.
Thanks,
Duane
 

Duane Frymire

Active Member
Duane,

At the moment I highly recommend that you use the 2 Engine option, and put your base in a better spot.

Never in my life have I seen a base in a location like you have there.
I envy you guys. This is an excellent base position in my world:) Actually I wanted to put it on the truck in the driveway which is where I initially had my T2 base for this job, but the LS base still doesn't have autonomous capability (would have used that base setup point and done a shift on it instead of setting on it, which I've done on that site in the past with the T2). I got quite a lot of this site done with the T2 as base when the leaves were on. So I'm getting results I expect from previous use, which are better than any other manufacturer to my knowledge. But, I'm not seeing advanced capability from the new engines. So, I'm thinking I'm doing something wrong.

What I'm really wondering is if I have some setting incorrect because of the continual re-setting of the engines. I've watched that screen before and it didn't re-set that fast; it would work and work and once a 2 fix solution came in it would stay at least for a bit. I would have to go in and manually reset the engines if I wasn't getting fixed solutions (see similar posts).

I'll try it in a better base position if I can find one, but for this site I need the lake to freeze a bit more. It is a tough site; there's a cliff blocking signals that you can't see in the pictures or video.

Yes, I'm pushing the envelope and this is not a condemnation of the new engines. But testing in ideal conditions doesn't really tell me anything.
 

Adam

Well-Known Member
5PLS
Yeah, it's your base location. I tested today with the 2 engine rtk. I had it set to accept after 2 epochs with a minimum 2 engines. I had 304 of 310 with .15 and all were within .2'. the rover was in a spot like your base but my base was in a much better spot.
 

Nate The Surveyor

Well-Known Member
Get that base out in the clear.
Just for what it's worth, imagine 2 sets of obstructions. Base to sky. Sky to rover. If you eliminate all obstructions at the base, then the only obstructions your system has to contend with is at the rover.
Put a fisheye lenses on a camera, point it at the sky. Take a pic. Repeat at rover.
Now, combine those pics. That's what you have going.
In a few years, it will work better. But, for now, you are just shooting yourself in the foot. I'd go so far as to say that if that's "not that bad" of a base site.... Then you really should buy a 33' to 50' base pole. Thread it up through the trees, stabilize it, and work off of a nail, using "reverse shift" on a regular basis. Either base (preferred) or rover should be in the clear.
Nate
 

Nate The Surveyor

Well-Known Member
I have nearly done this:
(I carry a Hunter's pocket saw most of the time)
Put t2 in my pocket. Pocket saw in pouch. Free hand climb a 40 to 50 foot tree. Cut off tree top. Make a 1" long x1/4" piece of all thread, with sharpened end. Put nut on it to protect threads. Drive all thread in top of tree where cut off. Place t2 on tree top. I always found a suitable site, but I'm ready to do this.
Nate
 

Jim White

Member
I have nearly done this:
(I carry a Hunter's pocket saw most of the time)
Put t2 in my pocket. Pocket saw in pouch. Free hand climb a 40 to 50 foot tree. Cut off tree top. Make a 1" long x1/4" piece of all thread, with sharpened end. Put nut on it to protect threads. Drive all thread in top of tree where cut off. Place t2 on tree top. I always found a suitable site, but I'm ready to do this.
Nate
1/4-20 Hanger bolts work really well with an impact driver to set them.
 

Duane Frymire

Active Member
Thanks for the replies, will try it with nice open base position.

Related question, with the new configurations should we be using "independent tracking" instead of "conventional tracking"? In satelite signals screen there's an option for one or the other. "Conventional tracking" is the default and what has been on in the past.
 

Nate The Surveyor

Well-Known Member
@Duane Frymire , There are stories behind my "put base in the clear" advice.
For years, I ran a Topcon Legacy E system. I still have it. It was a common trick to use a float to get near a corner, and compass and tape to set or tie the corner. We always shot things twice. Once on ctrl nail, and once on the actual corner. Just one obstruction, near the base. Could cost you 1-2 hrs of time. We carried these habits with us, into "Javad Land". Since the T3 is a relatively new setup, and not all the software is complete, and "multi-path mitigation" is sort of "starting over", it makes sense to not demand that the base act like a highly mature product, when it's not.
Respectfully given,
Nate
 

Matthew D. Sibole

Well-Known Member
5PLS
I try not to have any trees within 150’. Doesn’t always happen but I would not have even thought of putting a base where you have it.

Thanks for the replies, will try it with nice open base position.

Related question, with the new configurations should we be using "independent tracking" instead of "conventional tracking"? In satelite signals screen there's an option for one or the other. "Conventional tracking" is the default and what has been on in the past.
 

Nate The Surveyor

Well-Known Member
the LS base still doesn't have autonomous capability
really? So, how do you work around this, with an LS on base?
And, from the rest of your comments, you have been using the site in the video, with the t2 on base. (If I'm understanding you).
Is this your first gps brand/system?
Many of us had previously used other brands. I did a lot of work with Ashtech Locus L-1 only units. They were only 8 channel units.
I learned their limits. (And pushed them) I learned that a 4 HR observation, could do a lot. I've done long observations with them. 12 hrs, 16 hrs, 24 hrs. 36 hrs. To avoid long traverses.
It's where you learn the limits.
N
 

Adam

Well-Known Member
5PLS
The LS base can still work with an autonomous position. You just have to shoot a waas point then select the point from the list. It has the capability but it takes a few more button presses than the standard base rover setup.
 

Duane Frymire

Active Member
really? So, how do you work around this, with an LS on base?
And, from the rest of your comments, you have been using the site in the video, with the t2 on base. (If I'm understanding you).
Is this your first gps brand/system?
Many of us had previously used other brands. I did a lot of work with Ashtech Locus L-1 only units. They were only 8 channel units.
I learned their limits. (And pushed them) I learned that a 4 HR observation, could do a lot. I've done long observations with them. 12 hrs, 16 hrs, 24 hrs. 36 hrs. To avoid long traverses.
It's where you learn the limits.
N
I normally do something like Adam mentions, or put on a previously known point. In this case I put on a previously known point that I had shot using rtk when leaves were on the trees and t2 was on the truck in position you see truck. I would have put the t2 on the truck, but thought I would see what happens with base on that point using all constellations. I've used worse spots as far as tree cover goes, but yeah I normally look for better spots for the base. Pushed it too far I guess. But from past experience I don't think it was just the trees, I'm thinking a tall cliff nearby had some effect, along with troposphere. I've had less desirable results with low/heavy cloud cover like there was that day.
I used GPS back in the late 1990's briefly, long occupations on HARN, but don't even remember what brand. Went to demonstrations and continuing ed over the years keeping up with developments, but nothing came along that would work in my environment (you've seen it now) until JAVAD 2014. It works wonders, so sometimes I get carried away and think it can do anything:) Which is okay, I like reverse engineering once in awhile.

What I think I've learned from this reverse engineering is that if I have trouble getting a fix, I can look at the screen in question and if the engines are continually resetting very quickly, then I know I have a problem with the base position. This is useful knowledge. Thanks to all.
 
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Nate The Surveyor

Well-Known Member
Duane, don't feel were jumping on you. We aren't. We are doing math. Like this:
1.) Set base in poor place, 2 days of work. Higher residuals, and only 15 min set up of base time.
2.) Set up base on top of mast, with guy anchors, set of base time is 30 min. Only one day of field work. And much smaller residuals.
Here is a good deal: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/233416383055
And, use paracord to stabilize it.
I usually find a good site for the base, instead of the mast routine. But, I'm ready.
Respectfully,
Nate
 
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