The Oblique Altimeter: A Theoretical View

Altimeter can measure the height of sea waves. Such measurements are carried out at zero incidence angle. The Brown model was developed to describe the waveform of the reflected impulse. There is no theoretical model for the case of oblique probing. In the Kirchhoff approximation the theoretical task about waveform of the reflected impulse at oblique probing was considered. In the result of the investigation the analytical formula for the waveform of the reflected impulse for oblique probing at the small incidence angles (< 12°) for a microwave radar with a narrow antenna beam was obtained. The dependence of the waveform of the reflected impulse on the width of the antenna beam, the significant wave height (SWH), the incidence angle and the distance from the radar to the sea surface was investigated. It is shown that the waveform of the reflected impulse depends on the SWH.