1. A system used to calculate exposure to solar radiation in a given wavelength range, received by a person in each part of a body, the system comprising:a wearable device having stable position and orientation with respect to the body of a person, the wearable device comprising position sensors capable of detecting position data of one or more points of the body according to at least azimuth and inclination with respect to a vertical line depending on the position that the body has during sun exposure;
a geolocalization sensor associated with the person;
a remote computing unit operatively connected to a satellite means to receive georeferenced data related to solar irradiation over time and to associate solar irradiance data to geographic position, posture and the orientation of the person or of parts of the body of the person over time, to provide an overall incident irradiance and a relative associated dose accumulated over time for each point of the body;
a portable telecommunication device positioned close to the person, the portable telecommunication device comprising:
a first communication interface connected to the wearable device and the geolocalization sensor for receiving first data related to the geographic position, posture and orientation of the person or of parts of the body of the person;
a second communication interface connected to the remote computing unit to send to the first data to the remote computing unit and to receive second data relative to the sun exposure of the person;
a means for the person receiving information associated to the second data relating to the person's exposure to solar radiation.