Research On Key Techniques Of Imaging And Simulation For Subsurface Sounding Radar

With the deepening of the Chinese lunar exploration project, it becomes more and more necessary to detect the lunar subsurface. For microwave has the aibilty of strong penetrability, it can penetrate the dry surface layer and revealing the internal structure of surface which is useful in ice layer and planet sounding.By Synthetic Aperture Radar, can subsurface be imaged by two-dimensional, and be analyzed more accurately.The electromagnetic scattering characteristic of the two layer model is the focus of the research. First the method of radar echo simulation based on geometrical optics, ray tracing and KA is discussed. Second the effects of the different parameters on the echo simulation are analysed, large scene radar echo is simulated.When the electromagnetic wave propagation in the medium, the phenomenon of refraction happens and the velocity of elcctromagnetic wave will also change. The traditional imaging algorithm will not be suitable for the premise of single medium. First the echo of the subsurface is researched, then the the improved imaging algorithm on wave number domain is used, last the resolution of two dimensions is discussed.Along with the increase of the frequency, the propagation loss of the electromagnetic wave in the medium becomes large. So the subsurface sounding radar usually works with the lower frequency band(10MHz), which leads to large size of the antenna.Thus the antenna will receive both nadir echo and off-nadir echo. If off-nadir echo arrive at radar at the same time with subsurface ehco, it’s difficult to distinguish the subsurface echo with the off-nadir. So clutter suppression is a problem that must be considerd. Thus the adaptive clutter suppression based on dual-antenna is proposed, which can suppress the clutter effectively.Last base on the research mentioned above, a set of subsurface sounding radar software is developed which has the function of scene generating, echo simulation, SAR image and clutter suppression and is suitable for vehicle, plane and satellite.