WISDOM (Water Ice and Subsur- face Deposit Observations on Mars) is a Ground Pene- trating Radar (GPR) that is one of the panoramic in- struments selected to be part of the Pasteur payload onboard the Rover of the ExoMars mission. These Pas- teur Panoramic Instruments (the wide angle camera PANCAM, the infrared spectrometer MIMA and WISDOM) will perform large-scale scientific investi- gations at the sites the Rover will visit. Among these instruments, WISDOM is the only one that can provide information about the subsurface structure prior to drilling. WISDOM has been designed to characterize the shallow subsurface structure of Mars. It will give access to the geological structure, electromagnetic na- ture, and, possi-bly, to the hydrological state of the shallow subsurface by retrieving the layering and prop- erties of the buried reflectors. In addition, the data it will provide will be used to determine the most promis- ing locations at which to obtain underground samples with the drilling system mounted on board the rover. This paper describes the WISDOM instrument particular attention is paid on its antennas design as well as on its operations during the mission. Eventually the first measurements performed with a WISDOM prototype on Earth are presented. They show very promising results to well below 2-meter depth.