Preliminary study of a ground penetrating radar for subsurface sounding of solid bodies in the solar system

This paper investigates the detectability performance of a breadboard model of a ground penetrating radar (GPR) for subsurface sounding of solid bodies in the Solar System up to a depth of tens of meters. The developed GPR uses a linear FM chirp signal whose frequency is linearly swept from 300 MHz to 900 MHz for 330 μs and can produce a narrower pulse of greater peak amplitude by applying a pulse compression technique. Vivaldi antennas are selected as the antennas of the radar system and designed by a particle swarm optimization (PSO) method to minimize the S₁₁ parameter in the operational frequencies. A laboratory experiment for the radar electronics demonstrates that amplitude modulation of a transmitted signal by specific window functions could increase its dynamic range. The S₁₁ parameter of the developed antenna is found to be very close to the desired value. Finally, subsurface sounding is simulated by modeling the two-layer subsurface structure. The simulation results reveal that the GPR could observe the subsurface structures up to a depth of 10-20 m from the air and a depth of 15-25 m from the ground.