I've had my new Topcon QS robot and an FC-250 running Topsurv 8.2.2 for a few weeks now. All my previous experience with data collectors has been with a GTS-303 and an HP48 running SMI, and I've never used a robot before, so this has been an almost 20 year jump in technology for me, and is like learning all over again how to survey - I feel like that FNG a few threads back. And yes, I've learned how to stack a dozen topo shots on the backsight!
Up until now, every problem I've had has been due to me doing something wrong, but I can't figure this one out.
I've been topoing a small wooded property, and have 300-400 topo shots. Out of all those shots, two have had the wrong horizontal angle recorded. For the latest one, the angle should have been about 80 degrees, but looking at the raw data, the horizontal angle reads 251-00-05. The distance, zenith angle, prism height, etc. all look correct. The earlier and later shots all look OK, just this one is off. The instrument was set to take just one direct sideshot. The distance involved is about 140 feet, a clear shot, but between tree trunks.
I know the instrument was looking at me at the time - I could see the tracking indicator light, so it wasn't aimed at 251 degrees, but that is what was recorded.
This happened one time earlier on this same job, but I thought it was just a fluke. So far, it's been obvious that the shots were wrong, but if it keeps happening, I might not notice that it happened.
Has this happened to anyone else, or does anyone have any ideas as to what might be happening?
Am I doing something wrong? Or do robots occasionally lie?
Thanks,
Jeff
I run a Topcon 9003 robot with a FC-2500 DC. I've now switched to Carlson SurvCE on the DC but for about 2 years I ran various versions of TopSurv.
I had a case where the instrument kept losing lock and automatically going into a fast "quick lock" style search without being told to. I suspected radio interference and switched channels on the problem went away. Later when my traverse busted by feet I went back and discovered that the foresight that I took while the instrument was acting strange had the correct vertical angle and slope distance but the horizontal angle was off by several degrees.
I suspect that the instrument went into search mode at almost the same instant that I pressed the button to store the shot. Somehow it used the last slope distance and vertical angle combined with a snap shot of the horizontal angle as the instrument rotated away from me. The key is to watch for situations where the instrument loses lock as you're taking the shot. It seems that there is a quirk that allows it to record the wrong hz angle when this happens.
I'm not sure if it's a coincidence but I haven't had this happen since switching to SurvCe on the DC.
Had a similar situation with a couple of shot from a Nikon total station. I was wearing a very reflective vest and we figured it reflected from the vest more than the glass. Same thing happened everything else looked good but a couple of shots were so far off that it was obvious. Just glad that the errors were big
Thank you for the reply. I was wondering about radio interference, but I have no way to check. This was an empty wooded lot between a residential area and a large conservation area, so I wouldn't expect any nearby radio noise, like I might in a more urban or industrial area. Of course, I could be wrong...
There were several cases where I lost lock just as I pressed the "save" icon; I don't remember if this was one of them. I had been assuming that if it let me save the shot, it already had all the data. I'll have to watch for this.
I've noticed that many people like SurvCE and dislike Topsurv. Topsurv is very different from the SMI I was used to, and the menus are inconsistent, with functions that are not where I would put them, but it seemed to be fairly complete (for my needs, anyway). I had assumed it would work the best with Topcon equipment. I wonder if I should consider switching, assuming SurvCE will run on an FC-250.
I had thought of this, but I wasn't wearing a vest here. I did discover earlier that you shouldn't leave your backsight prisms uncovered...
"I did discover earlier that you shouldn't leave your backsight prisms uncovered..."
..or set your traverse up in line with a majority of your topo 🙂
edit: If there is really one cool very simple tip to using the robot it would be waving the rod from side to side and watching your Hz? (if your DC displays the angle in real time) increase or decrease to confirm you are tracking the prism. I also think the instrument likes it's own reflection in some types of tinted or mirrored windows.