SceneScan®: the first targetless laser position reference sensor

This process is repeated until what is observed by the sensor no longer closely matches the reference scan data. The system then updates its map by incorporating new data from the different viewpoint. Subsequent scans are then matched to the updated reference scan and this process continues throughout the tracking session. This allows us to continue tracking as we navigate around an asset.

The SceneScan generates its map in a 2D plane however at the start of a tracking session it optimises which 2D slice tilt angle of the sensor to scan. This optimisation can be shown in the form of a colour coded 3D plot. In the plot above we have the following colour code:

Green: Acceptable or better tracking performance from this slice

Red: Poor tracking performance from this slice

Grey: Excluded (part of the sensor vessel)

Blue: Sensor tilt angle out of range for tracking should the vessel move in close to the asset.

Verification against other sensors

We can use data recorded from the CyScan and RadaScan to compare performance of the three sensors. Looking at the overall trend in range and bearing for the station keeping we can see that the three sensors remain consistent with each other.

Looking closer at a small period of this run we can see that the three sensors look to be in good agreement about the vessel motion. The SceneScan was reporting a smaller overall level of wave motion due to its lower mounting height. The locations of the reference frames for each sensor were slightly different as well.

Results against a drillship

We have shown techniques used to evaluate the performance of a targetless position reference sensor and shown these used to evaluate a laser position reference sensor.

References

MTS TechOp OPD 14 – PRS and DPCS handling of PRS, September 2017