I haven't been on in quite some time, but decided to check in and read this.
We have quite a bit of difference in the use of GPS than most of you, as almost all we do is stream restoration. We do not have to do any take-offs as the designers provide us with a surface, and our RFPs include quantities for most items. Some are tremendously complex including pictures and orientation of logs used in wood structures, riffle, glide, and pool grading, and floodplain grading. Some include just simple linework and surfaces. We often require different layers for each component as there gets to be too much information on one screen, primarily linework.
With the help of our Sitech representative we have been able to learn how to import files in xml, csv for control points, and dwg. We use TBC to export to GCS 900, and it is good to be able to export layers individually as necessary. We have CB 460 on a D6T, 345D, and 320D. A couple of months ago we purchased a next Gen 330 which comes with 2D capabilities and purchased the 3D portion from Trimble. It cost $7500 to unlock the computer in the 330 in order to be able to use 3D. I believe Trimble offers an "Advanced" version for better function of the automatic capabilities, but I understand that is an additional $8,000, and we really don't use the automatic features much anyway. Seems we are getting to the point where despite buying the machine, one doesn't necessarily own all of its capabilities. I imagine soon everything will be on a yearly subscription basis. The Next Gen machines are electric over hydraulic rather than pilot controls, and I hated it at first as the feel of the controls wasn't nearly as nice as our older machines, but we are getting used to them and they can be adjusted.
One thing that the rover and TBC has been very beneficial for is being able to do pre and post construction surveys, and to be able to produce earthwork reports comparing the two surfaces. On one project that we bid on there was a requirement to hire a licensed surveyor to perform pre and post surveys to establish a quantity of material moved, as that cost line item was an actual quantity. There was approximately 110,000 cubic yards of mine tailings to move in order to restore a floodplain. We bid that item including the surveyor' cost, which was about $25,000, and included drone flights but he could only assure accuracy to within .3' as the tailings had come out of a dredge and were not at all uniform. In an alternate proposal included in our proposal we suggested that we would flat top the tailings, shoot the cut area with our rover, and then shoot it again once we had completed construction, and then provide the data to the engineer as well as our Sitech Rep to calculate the volume of tailings moved. They Project Manager accepted our alternative calculating that even if our data was off in our favor by 5% or so the savings in not having to hire a licensed surveyor would be a push. We prepared our own earthwork report via TBC (very easy to do) and came out within 100 cubic yards of what the engineer calculated using our data. I am not smart enough to know exactly why there was any difference, but I believe it had to do with trimming triangles on the surface edges.
The Next Gen is pretty impressive as the screen in the machine shows shading in between lines, and really helps to see what we are building beyond the reach of the boom. The download process is different as the calibration file is integrated into TBC and then exported from there, whereas with the CB460 we are able to add a cfg file independently on the jump drive. The Next Gen also contains the ability to add files/designs directly to the machine from the office, though I don't see us using that feature.
As I am sure many of you have learned, the old free TBC versions did not require the licensing to complete most of the tasks that we use. I bought a lower level of license for our newer version (under duress), but still have the older version just in case.
I bet you will find that after becoming comfortable with the new technology there is no way you would ever go back, but swallowing the initial cost is less than palatable!
