I've been asked to investigate continual 3D monitoring, for a period of several days to a fortnight, of a set of power poles that are to be affected by LW subsidence. We have the ability to place reflective targets up the poles at regular intervals. My thoughts were to set up a Trimble S6 outside area of subsidence influence and read continual rounds to poles and at least two other reference stations - any other thoughts - radar - laser scanner?

Go with auto targeting theodolite and reflective targets, set up instrument and backsight points in an area of competent ground , auto record several dual face rounds and run results through compnet.

OK – I’ve set up an S8 to read multiple rounds at various time intervals between rounds, depending on rate of subsidence, to a total of 12 monitoring targets and 3 base targets. My understanding of Compent is that it processes whole job. I've got several job files with up to 22 rounds over some 60 hours. I'm starting to accumulate a hell of a lot of data. Do I break each round out of Compnet and process it separately, very time consuming. Any thoughts?
I'm also attempting to use Trimble 4D, but the learning curve is very steep. I'm lead to believe that 4D recognises each round by time stamp and processes as individual round. Is there anyone out there with some experience with 4D?
Ps – I’m still to speak to Frank Smith re Compnet processing and I’m still reading the help files in 4D.

Trimble 4D worked a treat - just dumped data from survey controller into 4D. Nominated control base points for resection calc, set-up station as auxiliary point and pole targets as monitoring points and the program did the rest. I was able to rotate the axis of the targets so that the program calculated displacements in relation to the rotated axis (rotated axis parallel to direction of LW retreat). Data plots were only time related and I was able to plot vertical, lateral, axial (relative to rotated axis) and total 3D displacement. Biggest issue was the way we secured targets, used duct tape to hold targets until Silastic cured, problem was duct tape peeled away obscuring some targets until tape completely fell away. Also had an issue with battery failing, S8 doesn’t give charge level indication for external battery and life of battery (heavy duty light truck) was about 3 – 4 days continual use. Should have used solar battery charger!