WelcomeFriday, December 9th, 2022
Long range reflectorless manual total station
The title says it all. Which manual total stations measure far (>1000m) reflectorless.
It is for sag line measuring for high capacity electricity corridors.
I had a demo of a trimble sx12 but he had some problems with 600m already.
600m is pretty far out there for transmission sag line measurements using DR, especially if there's any wind.
Both Leica and Trimble flagship TS are spec'd for 1000m, but Leica generally has the edge when it comes to reflectorless. Can't say I've used them much at much over 300-400m refelectorless though.
The S7 has an extended DR range mode. Only tried it out to about 900m, and it worked well but I wasn't trying to tag a hanging wire.
Dunno about Leica's top gun, but S9 DR Plus is supposed to be the best of the Trimble lineup. 600m for poor reflective surface, 1200m for good reflective surface.
I had trouble with the sx12 using the prism, but that was radio related as I was with the TSC7 grabbing a 1/4 sec corner. the real world specs always prove the sales people might be pushing the agenda too hard, in not optimal sales pitch scenarios.
the real world specs always prove the sales people might be pushing the agenda too hard, in not optimal sales pitch scenarios.
I personally would like to see a cooperative relationship between Leica and Javad. I don't know or concern myself about the companys themselves. This is strictly a PRODUCT viewpoint. They both are cutting-edge products. And, they both could use some "taming". Ie, easier cogo, and less button presses, to "get there from here".
Leica has the "edge", from my point of view.
Ditto Leica over Trimble for long and short range reflectorless.
All my data is anecdotal but having used both in monitoring projects with reflective tape and general topo location, Leica had greater precision in the former and less issues with off perpendicular angles with the latter.
I had a R1000 rated Leica but wasn't able to test its max distance often. There's also the as big or bigger benefit of the higher quality optics that come with a Leica.
At that sort of distance the result is going to be affected by the spread of the beam - you could get a significantly different "average" distance depending on whether you are observing single, twin or quad conductor groups, since all the conductors on any phase would fall inside the coverage of the beam and the DR might pick up on any of them.
When I was doing a lot of OHL work we used two instruments to form a base (made an adaptor so a target could straddle the instrument head enabling each to use the other as an RO) and did the conductor observations as near simultaneously as possible by intersection. We used the spacers on twin and quad lines to give the observing positions. That also meant we kept the observation distance down to generaly under 500 metres to reduce any refraction effects. If top of tower coordinates known then that also fixed the observing stations. Typically it would take less than 10 minutes to observe sags and all attachment and suspension points for a single span. Recorded time on each observation so readings could be subsequently corrected for line load variations if those were available from sub-station.
Interesting follow up to my post above.
This morning I was clearing through some old storage boxes in our store when I came across a set of notes and OHP transparencies, for a presentation I did to the UK National Grid back in 1988, on the subject of errors generated by the "new-fangled" EDM which was coming into use!
Older readers will recall that the first generation of total stations introduced something called "Remote Object Elevation" whereby the height of anything could be measured by reading to a target directly underneath and then elevating the telescope to point to the object. All the manufacturers had assumed that this would be to get things such as gutter heights etc. where the object was not far above the target or tree heights where absolute accuracy wasn't needed - none had predicted that it would be used for things like conductors, possibly suspended across valleys etc. The result had been a spate of error-full surveys of powerlines where the surveyors could all "prove" that it was correct because they had followed the manufactjurers instructions.
I must see what is in the next pile of storage - let you know!