The solar core is the region where all the nuclear reactions take place and, therefore, where the energy is generated. Understanding the physics of these internal layers, the theory of solar and stellar structure can be settled into form grounds. However this is the most unknown region of the Sun. Helioseismology, mainly through the gravity modes (g modes), is the adequate technique to understand its physical structure and dynamics. The detection of solar g modes is a great challenge due to their low predicted amplitudes and the high noise level at low frequencies, where they are expected to be. So far, from earth based observatories and networks, this task has proved to be impossible. Therefore space based instrumentation has the only chance to detect such modes. This is the case of the helioseismology experiments, GOLF, VIRGO and MDI on board SOHO spacecraft. In the present work, we have studied in detail the GOLF experiment, a resonant scattering spectrophotometer. A complete numerical simulation has been made, which allowed us to define and to evaluate different signals combination and their calibration methods, to finally obtain the integrated solar radial velocity and magnetic field. To face the problem of the solar background noise spectra we have simulated it and a new signal has been studied: the differential velocity Δ V, which reduces the level of simulated noise allowing a direct identification of the g-mode spectrum. This signal has also been tested over a series of 69 days span measured by an earth based resonant scattering spectrometer: the SPACE-3.