Restoration of turbulence profile from scintillation indices

An algorithm that permits one to measure atmospheric turbulence by statistical analysis of light flux fluctuations in four concentric-ring apertures is described in detail. It consists of computing the scintillation indices for each aperture and pairwise aperture combination and in fitting the set of measured indices to a model with a small number of turbulent layers. The performance of this method is analysed by means of simulations and using the real data from a multi-aperture scintillation sensor. It is shown that a turbulence profile with a vertical resolution of Deltah /h similar to 0.5 can be reconstructed and that the errors of the measured intensities of turbulent layers are typically around 10 per cent of the integrated intensity. The integral parameters such as the seeing and the isoplanatic angle are measured with few per cent accuracy.