| 摘要 |
PURPOSE:To make it possible to remove a clutter by selecting the optimum combination of the beam width and pulse width of an antenna, as to a pulse radar which receives scattering power from rain from skies and the ground surface and then observes its state. CONSTITUTION:Rader antenna 1 emits a beam at angle thetaO. When the pulse width of the radar is denoted by (tau) and the velocity of light by (c), the hatching part encircled by Ctau/2 and beam width DELTAtheta is rain observation region 3. Although almost all radiation power is contained in beam width DELTAtheta of the radar antenna 1, part of power is radiated in all directions except DELTAtheta, which is side-lobe radiation. Therefore, the range gate system receives scattering power from AB and A'B' of ground 2 contained in the width of a distance a half (ctau) even by a side lobe and if this reception level is higher than scattering power, the rain observation becomes impossible. Namely, ratio (eta) of rain scattering reception power to ground clutter power should be less than a certain value. For the purpose, the combination of beam width DELTAtheta and pulse width (tau) should be set to the best one. |
