More than likely a LIDAR survey.
The pans on the outriggers are the GPS antennas. Using C/A (carrier aided) GPS the accuracy is probably down in the +/- 150 mm range although possibly not in realtime. The GPS data is usually post processed against a fixed base station. The pans under the antennas are to stop reflected signals.
This arrangement would give you very accurate platform orientation in pitch roll and yaw.
There are many different proprietary software algorithms to achieve a GPS position and some C/A units will just not work under a rotor like this one.