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I have a serious problem. Shooting forsights and baksights for my fellow theodolight user on gridlines, I set a nail on that same gridline. When I attempted to interline on that nail, I discovered my foresight and backsite were way off. I was resecting all over the site shooting gridlines using verified verified 5 different backsite. All residuals were within 3 mm. How is this possible? Previously my points, prism and prismless were within two mm of two different top end Leica's, two different professional surveyors. It's a new top me total station running an old version of SurveyPro. Please please help me solve this. I have tonnes of respect for you all, I'm no where near as experienced as most of you and desperately need/request your input on this. Thanks to those whom help.
This Content Originally Published by a land surveyor to Land Surveyors United Network
I read only now your post, so I don't know if you solved the doubt ...
Your total station has a 5" angular accuracy and ±(3mm+2ppm) EDM linear accuracy; with these values you can analyze the network adjustment and estimate the point accuracy you expected. As you surely know, it depends from many factors: network's shape, number of points, extension, constraints and equipment that are you using, of course...
Is also important to set correctly atmospheric correction (ppm).
About the comparison con other instruments, please you pay attention to specifications of the other gun. If the other survey was made, for instance, with a TPS1202+, this total station has a 2" angular accuracy and ±(1mm+1ppm) EDM accuracy. In this case, the honest GPT-3005N can't made a miracle ....