1st December 2021
Microwave Sensing, Signals and Systems
Delft University of Technology - Netherlands
Antenna systems and algorithms for subsurface microwave imaging
Nowadays, microwave imaging is broadly used for non-destructive testing, concealed weapon detection, through-the-wall imaging, land mine detection, road pavement inspection, underground facilities survey, archaeological investigation, imaging of biological tissues, etc. In all cases, the scene of interest is illuminated by natural or man-made sources and image is formed based on received scattered electromagnetic field. For subsurface applications the image is formed typically by means of digital signal processing of scattered field, which is measured at different spatial locations by antennas. The tutorial is focused on selection of measurement locations of the scattered field within the imaging aperture and main digital processing algorithms used to create an image from the measured amplitude and phase of the scattered field. Particular attention is given to advantages of using polarization properties of electromagnetic field.
2nd December 2021
Dipartimento di Matematica e Fisica,
Roma Tre University - Rome, Italy
Searching for subglacial liquid water on Mars using MARSIS
Dry and cold geological materials forming the outer shells of rocky and icy planets (and satellites) are a "perfect" environment for deep radio wave propagation. The first attempt to use a radar sounder onboard a spacecraft to investigate the subsurface of another solar system body, which was named ALSE (Apollo Lunar Sounder Experiment), was made during the Apollo 17 mission. At that time, ground penetrating radar technology was in its infancy, nevertheless ALSE was able to detect several structures in the Moon subsurface. More than twenty years later a new radar sounder, MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding), was designed and mounted on MARS EXPRESS spacecraft to investigate the Martian crust down to several kilometers. MARSIS surveyed the Martian subsurface for almost fifteen years before detecting an anomalous bright area below the South Polar cap, at Ultimi Scopuli (Planum Australe) which has been interpreted as the first evidence of subglacial liquid water. Subsequently, new radar data collected in the same area allowed the identification other three wet areas around the main body of water previously discovered, suggesting the existence of a complex water system below the ice. In this talk we will describe how the first large water body and the other small ponds has been discovered.