Simulation of complex visibilities in synthetic aperture imaging radiometry with the Aaid of GPU

The basic observables of an imaging interferometer by aperture synthesis are the complex visibilities. Under some conditions, they can be simulated with reference to the Van Cittert-Zernike theorem. However, owing to the underlying assumptions some important effects that may alter them cannot be taken into account. This paper is devoted to the numerical simulation of complex visibilities with very few assumptions. The emission is modelled with random short wave trains. Each wave is transported to the antennae, transmitted to the receivers and the corresponding signals are cross-correlated. From emission to correlation, perturbating effects can be introduced. However, owing to the amount of calculations to be performed, massive parallel architectures like that found in GPU are required. To illustrate this modelling, numerical simulations are carried out in the L-band in reference to the SMOS-next project led by the french space agency. The results are discussed and compared with the estimates provided by the Van Cittert-Zernike theorem.