One thing that is a bit different from a conventional survey is the use of a retroreflective card that is held on the station to which you are shooting. This was needed as a way to solve the problem of being sure that you were actually measuring the distance and direction to the station when doing a passage scan with the LIDAR. Since it is impossible to hold the Caveatron perfectly on station while traversing with it, the Caveatron only gets valid position readings when it hits the retroreflective card and all other surfaces are ignored. So, as you move down a passage with the Caveatron, you don’t need to be pointed exactly at the station continuously, just from time to time. The Caveatron does the rest, filtering out off-angle measurements and interpolating between valid measurements. Having the card also helps with the accuracy of station-to-station shots in that it ensures you are actually pointed exactly at the station and not measuring something next to or behind it.