network rover with Spectra Precision Ranger 3

I don't have the equipment or software to test but I find this very interesting. Are you able to test with a base/radio correction to see if the same thing happens? You may be the only one "with the problem" or you may be the only one who is "aware" of the problem. Do you have open skies when you see the differences?

I've done some testing with network solutions (using Leica GS14 with CS15 controller) and found that for some reason under less than ideal situations (canopy of varying degrees) the results are completely unreliable, whereas with the base/radio setup I haven't seen it quite so wildly incorrect. I've seen 3DCQ estimates of ~0.08m and then when comparing it to the known position have seen it out by up to ±4m 3D, which is a substantial difference in my opinion 😐 . I don't have enough data to come to any conclusions but I would love to set up a testing procedure that could be used for GNSS, same concept as the baselines for EDMs, but for RTK receivers. Varying conditions from optimal to poor, compare results to known positions, compare actual position quality to the estimated quality, etc, etc.

Jacob

Jacob, thanks for sharing.

Yes, I've tried all varying conditons..open sky, close to trees, bldgs, etc. Even called the network in real time to see if I'm fixed. I caught it by my crew shooting the mons in a city block, the two northerly mons related within themselves, they lost lock, tied the other two...they later had the robot and checked out to one of the mons and it was off. Since then I have no faith in it. Would rather do static to get project to state plane. I've tried a topcon collector to it and it's fine, so I'm wondering if others running a spectra ranger with a gr5 are seeing this.

But have not tried the base with it to compare. We just use this system for control on the network.

I don't run the same setup, but do use a Specta Precision Ranger 3 with Survey Pro. We ran into some problems when upgrading from TDS Survey Pro to Spectra Precision due to when and how the collector was collecting data. With TDS data wasn't collected until you took a shot and the specified number of epochs were observed and averaged. With Spectra Precision as soon as you enter the real time screen it begins a static on occupy session and stores the solution when pushing store. Both work fine, but with TDS we had grown accustomed to entering the real time screen while walking to the next point, which obviously created a problem when doing the same with Spectra Survey Pro.

This issue could be totally unrealated to your problem, but could be aomthing to consider. We consistently get a small shift (+/-0.1') when breaking lock on our network here in Ohio.

I think a tenth is normal in an rtk network. I'm seeing quite a shift that's indeed odd. Might be worth just migrating to a topcon collector.

> Anyone with a similar set up see this or go out and maybe give it a whirl for me and see what you get?

I am running the same setup. I only have access to the California Real Time Network (CRTN) which is GPS only. The base I was connected to is a little over 13 miles away. I was able to measure a position, dump the receiver and stake out the point within 0.03' H and 0.10' V. I went over and shoved the rec. under the truck, re-fixed and measured another point then staked the previous point with the same accuracies. I ended the survey and restarted the base and same thing: 0.03' H and 0.10' V.

I would look to an internal setting in the receiver for possible answers. Do you have T.R.U. on your Ranger?

Thanks for writing in here. I thought the topcon dealer would get all the oaf settings correct. I don't have tru on the ranger but do in the office. I'd be interested in seeing a print out of yours, however. That way I could see anything obvious.

i would suggest going through your settings..are you storing fixed positions only? how many epochs do you take before you store a point? is this .5 foot repeatable and is the direction the same? what about the network? is it switching base stations??is the stakeout in offset mode? do you have values in the offsets...too many questions

> I'd be interested in seeing a print out of yours, however. That way I could see anything obvious.

Right, wrong or indifferent; here are some screen shots of the Positioning settings in my rover receiver.

Not new to gps should have been mentioned on my first post. Very good with many brands, mainly Trimble with TBC. But I get your questions since that wasn't mentioned. This topcon and spectra collector is a new setup I'm not used to. Storing only fixed positions with superb h and v precisions, pdop is good, not storing or staking in offset mode, have tried all sorts of epochs(typ 10 epochs), have called the network and work closely with them(I'm fixed on their end too while calling in real time to check on my status), the network is very stable with a lot of users, the folks here at the local topcon dealer are perplexed just as much as I am.

The half a foot is this go around, with the first gr5 they gave us..we'd see anywhere from a half foot to 30 feet. But sometimes good(less than a tenth)! Maybe if we send it back to the engineers at Topcon it'll be just skookum when it returns?! This rover set up was not my first or second choice, main branch office made the order for this stuff with no field tests.

Thanks for this, I'll take a look at these just to compare. I would say Topcon should know which ones to set, but who knows these days? But I appreciate your time for posting this. I'll post back to let you know the verdict.

Was this ever resolved? We have a topcon GR5 and we are looking st purchasing a Ranger 3 with survey pro.

The error that you are seeing is a phase center issue caused by Survey Pro. This error is typical on both a GR3 and a GR5. Take your verical error and add the phase center...more than likely you'll get something that looks like a good vertical at that point.

This has been ongoing in various versions, not all, but some of Survey Pro.