Navigation, 2

These start by measuring acceleration and then determine by successive integrations the velocity and then the displacement from a known starting point. Therefore there must be an initial calibration. As with all integration systems, they are subject to a serious drift. Therefore a compensation for drift is required and a periodic recalibration. A number of research projects are being carried out to adapt this system to be used at sea for a reasonable price. The attraction of this research is due to the enormous potential market and the advantages of this navigation system : absolute uniformity between shot point distances, the ability to carry out exact gravimetric studies, the ability to work in deep water, far from the coast at all hours of the day and night.