Impact of Mars ionosphere on orbital radar sounder operation and data processing

Orbiting radar sounders may become the primary tools in global investigation of Mars subsurface. Orbital radar sounding of Mars is complicated by the presence of a significant ionosphere. The need to penetrate deep requires radar operation at a MHz frequency regime which makes ionospheric distortions unavoidable. This paper addresses the issues that a radar sounder will face when operating close to the ionosphereʹs plasma frequency. Although the results of this paper are general, the main focus is Mars Advance Radar for Subsurface and Ionospheric Sounding (MARSIS) that will arrive at Mars in early 2004 aboard the European Space Agencyʹs Mars Express Spacecraft. This paper will quantify the impact of the ionosphere on the radar sounding operation and data processing and will provide potential schemes for correcting the ionospheric distortion.