Automatic Sound Velocity Refraction Error Correction Tool coming with Qimera 1.6
QPS has worked together with the Technical University of Delft (TU Delft), The Netherlands to implement their sound speed inversion algorithm in QPS Qimera. The TU Delft algorithm allows for a completely automated refraction error correction.
The algorithm works by taking advantage of the overlap between survey lines, harnessing the power of redundancy of the multiple observations. For a given set of pings, the algorithm simultaneously estimates sound speed corrections for the chosen pings and their neighbours by computing a best-fit solution that minimises the mismatch in the areas of overlap between lines. This process is repeated across the entire spatial area, allowing for an adaptive solution that responds to changes in oceanographic conditions. The main advantages are that the algorithm is automated and objective. This overcomes the limitations of other solutions which require manual review and adjustment of “fudge factor” correctors that are inherently subjective. It is also physics-based in that it honours the physics of acoustic ray bending. For accountability, the algorithm also preserves the output of the inversion process for review, vetting, adjustment and reporting.
The image on the left shows the average depth of the survey area before and after applying the sound velocity refraction error correction.
The image on the left shows the standard deviation (2 Sigma) before and after applying the sound velocity refraction error correction.
The below image shows a slice of the survey area before and after applying the sound velocity refraction error correction with each line having a different colour.
This Automatic Sound Velocity Refraction Error Correction Tool will be available in Qimera 1.6 currently due out early 2018!