Centimetric seafloor Geodesy for seafloor photogrammetric surveys

Tectonics is closely linked to geodesy. In particular, the displacement of tectonic plates can be measured by GNSS on land. However, GNSS measurements of plate displacement in the ocean are much more patchy, confined to the islands. This is due to the non-propagation of the GNSS signal in water. A positioning propagation method was developed by the American Spiess in the 1980s to solve this problem. His method is based on the fusion of GNSS in the atmospheric environment, and acoustics in the marine environment: it is called GNSS/Acoustics or GNSS/A. The field was subsequently developed in the USA and Japan due to the high tectonic risks present in their territories. This method works, but its worldwide deployment is limited by the cost of the equipment and its immobilization on site. The aim of my thesis is to reduce the cost of a time series by adding marine photogrammetry to GNSS and acoustics, thereby eliminating the need for hardware.