Base-Rover Setup

Aaron S

Active Member
I have my shiny new Triumph 2 and HPT435BT that I'm going to use for a base station and run full-on beast mode. I'm struggling to understand the setup. In my past life with yellow equipment, there were separate base options, and rover options stored in one survey style. Now, the "survey style" concept is divided into General and Action groups, right?

Well, when I go to setup a General Group for the T2 RTK with UHF radio, it says right up front if I'm doing base or rover... well I'll be doing one of each. Is there a cheat sheet somewhere to help me get this setup right and understand it better?
 

Nate The Surveyor

Well-Known Member
John Evers walked me through it. There is a little pile of stuff, that it's best to simply get from Tech Support, at this stage in the game. Once you are set up, you won't need it often. My setup profile has changed 2-3x since I got mine a yr and a half ago.
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Aaron S

Active Member
The Setup profiles are fully explained on page 30 of the Quick Start Guide, Base/Rover Setup is on page 32.
That's for the Action groups, I'm looking for details on the General group settings - It seems like I need 2 separate "General" profiles, one to send TO the base at startup (UHF protocol, modulation, etc.) and one for the LS to use after the base is running.
 

Aaron S

Active Member
HUGE thanks to Mr. Sibole for taking the time to talk me through the setup over the phone yesterday. It really made sense once I understood that the LS tells the base what it wants the base to broadcast. This is such a foreign concept to someone who's only used the other guys (spelled very similar to "trouble") all these years where you have a setting for the base, a separate one for the rover, and you'd better hope they match and you didn't overlook anything or it'll never work. Like he said, I have to un-learn the way I've been doing it because the Javad is a totally different approach.

Case in point - I spent 4 hours yesterday morning troubleshooting a yellow base/rover setup for some engineers and went back and forth on settings for the base/settings for the rover... do the broadcast settings match? did you set it the same in the rover and base (not necessarily)? bad cords? bluetooth problems? There were a thousand things that could be going wrong. Compare that with the Javad approach: enter the setup that the rover wants to use, and it tells the base "do this please". The settings always match.

The support you get for this equipment is such high quality. Imagine - talking live over the phone with an actual surveyor who was literally on a jobsite at the time. Or this great message board - all for free! Again, yesterday we couldn't get the other guys' stuff to work and our "maintenance agreement" had expired so they weren't really interested in upgrading any of the software. You have pay them a yearly fee to support the equipment that you already paid twice as much for compared to an LS. This was a great decision to switch to Javad. There's been some inquiries for Javad from others in my agency too - the LS in my profile pic usually generates some interest.
 

Nate The Surveyor

Well-Known Member
I don't know if anybody has said this yet. But, the TALLER your base radio antenna is, the better range you will get.
Just a "heads up". (This is true of pretty well all UHF systems, not just Javad...)
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Aaron S

Active Member
Now that I can do DPOS, is it acceptable to set up a base (on a sturdy setup in wide open sky) but not over a physical point in a temporary setup? I got the idea from the website where they mount the T2 on a vehicle roof.

The reason I ask is I have a bunch of corners to shoot, scattered all around. They are far enough apart that I won't be able to get more than a couple from a single setup, and once I have the shot, I won't be using that base point again. Are there any dangers that could happen by not having a physical base point to set up on?
 

Matt Johnson

Well-Known Member
5PLS
Now that I can do DPOS, is it acceptable to set up a base (on a sturdy setup in wide open sky) but not over a physical point in a temporary setup? I got the idea from the website where they mount the T2 on a vehicle roof.

The reason I ask is I have a bunch of corners to shoot, scattered all around. They are far enough apart that I won't be able to get more than a couple from a single setup, and once I have the shot, I won't be using that base point again. Are there any dangers that could happen by not having a physical base point to set up on?
There is really no need to have a physical base point or use reverse shift unless you are staking points or intend to stake points in the future.
 

Adam

Well-Known Member
5PLS
Now that I can do DPOS, is it acceptable to set up a base (on a sturdy setup in wide open sky) but not over a physical point in a temporary setup? I got the idea from the website where they mount the T2 on a vehicle roof.

The reason I ask is I have a bunch of corners to shoot, scattered all around. They are far enough apart that I won't be able to get more than a couple from a single setup, and once I have the shot, I won't be using that base point again. Are there any dangers that could happen by not having a physical base point to set up on?
I do it all the time. T2 and radio mounted on my truck. I also use steel cables to lock it down. In my opinion it's the only way to roll.
 

Adam

Well-Known Member
5PLS
Now that I can do DPOS, is it acceptable to set up a base (on a sturdy setup in wide open sky) but not over a physical point in a temporary setup? I got the idea from the website where they mount the T2 on a vehicle roof.

The reason I ask is I have a bunch of corners to shoot, scattered all around. They are far enough apart that I won't be able to get more than a couple from a single setup, and once I have the shot, I won't be using that base point again. Are there any dangers that could happen by not having a physical base point to set up on?
Also, you can set the t2 up to connect to a jetpack and to your rtn automatically so when you start your base it's using a fixed position.
 

Shawn Billings

Shawn Billings
5PLS
Here's the skinny on what you are proposing, Aaron...

You can absolutely set up the base with an autonomous position, perform RTK of all points within range of the base radio and later process the base to CORS. The DPOS process in J-Field will translate all vectors from the autonomous base position to the CORS derived position of the base. Depending on your local CORS, you can actually get a solution at the top of the hour after the end of the session. This means if you stop the base at 10:10am, or 10:55 am, you can process at 11:00am, and get a CORS derived base position. This is provided that your local CORS upload hourly. Most do except for the PBO stations which I believe still only upload every 24 hours at 0 UTC.

Now for the things to watch out for...
If your base file gets botched, you're session is lost with no way to recover the anchor point for the session. This is extremely, extremely rare, but a possibility. We have many tools now to recover DPOS sessions, so it is even rarer than it once was. But there is still a chance. A more likely issue is the duration of the observation. More time = More accuracy when it comes to CORS processing. I just completed a survey in which I occupied the same base position on seven different days. I sent each file to DPOS for processing the base>rover and the base>CORS. I held the first day processing for the remaining six sessions. Here is how they differed (all distances are US Survey Feet):

Day 1 (414 minutes)
0 N, 0 E, 0 U (Held)

Day 2 (405 minutes)
+0.003 N, +0.005 E, +0.026 U

Day 3 (332 minutes)
-0.017 N, -0.013 E, -0.020 U

Day 4 (240 minutes)
+0.058 N, +0.083 E, +0.069 U

Day 5 (356 minutes)
-0.013 N, +0.012 E, +0.020 U

Day 6 (267 minutes)
-0.033 N, +0.026 E, +0.020 U

Day 7 (376 minutes)
+0.016 N, +0.009 E, -0.007 U

Day 4 is the shortest observation which serves to prove my point. I would generally expect better results from a 4 hour session, but it is telling that the shortest observation also proved to have the poorest accuracy. Day 6 was only slightly longer (by 27 minutes) and is the second worst accuracy. Better than Day 4, but not as good as the others with over five hours of observations. Of course, your CORS geometry will be different from my CORS geometry, so you may experience better or worse results with similar time spans. If you are looking to have a quick set-up at each base point and tie a few RTK shots, then advance to the next part of the project, I think you may be opening yourself up for diminished accuracy. It depends on your project requirements as to whether the loss of accuracy resulting from short base observations will exceed your error budget. It will also depend on your CORS as to how much accuracy will be lost due to shorter observations.
 

John Evers

Well-Known Member
5PLS
The focus of what Shawn is pointing out relative to your question is that you can expect the positions of your "groups" of rover shots to match within in at best 0.03' uncertainty, up to to 0.1' uncertainty. (x2 position error). If your sessions are only 2 hours, I would expect up to 0.2' uncertainty.

I try to always have all points match a little better than 0.1', but I can think of hundreds of tasks that would be more than perfectly served by that level of accuracy.
 

Nate The Surveyor

Well-Known Member
If you have short occupation times,you could:
Set your base on some control monument, then reach out, with ppk, and 10-15 min (these would be my overkill numbers), and set out control.
Radialy, over a 10 or 15 mile radius.
Then use this control, to work off of, for your short occupation times, (short base time).


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Aaron S

Active Member
Also, you can set the t2 up to connect to a jetpack and to your rtn automatically so when you start your base it's using a fixed position.
That is mind boggling - doing it that way, I wouldn't need to reverse shift anything.
 

Jim Frame

Active Member
Also, you can set the t2 up to connect to a jetpack and to your rtn automatically so when you start your base it's using a fixed position.
Adam, can you describe how this is done, and how it can be overridden when the base is set up on a known point? Right now I use my LS to establish a point via RTN, then swap in the T2 and send the position from the LS to the T2. When I return on another day I use the base position previously established rather than getting a fresh RTN position for it.
 
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