A Vertical Reflection Ionospheric Clutter Model for HF Radar Used in Coastal Remote Sensing

A theoretical model of the high frequency (HF) radar ionospheric clutter for the case of vertical incidence is presented in this letter. Assuming a pulsed dipole source, the equation of the received electric field after vertical reflection by the ionosphere is first derived. Then the relationship between the ionospheric reflection coefficient and the ionospheric electron density is incorporated into the development of the ionospheric clutter power model. In order to investigate the power spectrum of this ionospheric clutter and its relative intensity to that of the first-order ocean clutter, the normalized ionospheric clutter power is simulated. Simulation results show that the horizontal ionospheric plasma drift velocity results in a Doppler spreading while the vertical motion introduces a simple Doppler shift.