I just wanted to start a discussion on targets and retros. Which targets are used by you or your firm? What is the distance and accuracy for those targets.?
What are your personal preferences for retro target
20mm x 20mm
30mm x 30mm
40mm x 40mm
50mm x 50mm
60mm x 60mm
Please share images, thoughts and opinions on this topic.
I have attached some designs of my own.
This Content Originally Published by a land surveyor to Land Surveyors United Network
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Target optimum size depending also what TS are You using. Assuming a standard 30X optical magnification, distance and visibility (ambient light condition) must be considered: with manual totals station, I suggest a min size of 40x40 mm @ 30 meters max distance (with closer distance, 15x15 mm @ 15 meters are enough)
Also, if You are using an automatic total station, "bigger is better" is not ever true: I remeber several years ago my tests with a Topcon IS-201 that was working well, in some condition, with smaller target, but usually need a medium/large target.
Sokkia NET-05A gives great performance within small targets: I using it in my building monitoring applications. With a 50x50 mm target (RS50R-N model) it can autopointing up to 50 meters far.
Often, the thickness of the reticle's lines determines the maximum sighting distance with the manual total station (reticle is overlapping the cross on the target and hide it!).
The resolving power of the optics (common value for currently total stations) is about 1.20e-5 rad.