| At present, polarization/dual polarization Doppler weather radar system are the mostly used methods in precipitation measuring both in domestic and at abroad. As the studies in particle scattering problems and the weather radar technology getting improved, the use of Dual-Polarization Doppler weather radar in measuring precipitation has significantly improved the accuracy of precipitation estimate. Meanwhile, the Bistatic Doppler weather radar becomes a new area which the meteorologists both at home and abroad get interested in. Currently, the Bistatic radar system is mainly used in wind profile retrieval, we suppose to study its probing characteristics in detecting precipitation and its effective volume problems.In this paper, we firstly introduce the coordinate of bistatic radar system, so as to discuss the scattering and propagation equations of a bistatic radar system detecting small ellipsoidal droplets. By using the derived bistatic weather radar equations over ellipsoid raindrops, we studied the propagation effect of bistatic radar system when detecting different distributed rainfall areas, all of the results are under the condition that all the ellipsoid rotation axis are vertical upward, we use these equations studied. Meanwhile, the expressions of the effective volume for bistatic polarization radar system sampling has been studied and the results provide a theoretical base for bistatic polarization radar antenna control, data process, sidelobe contamination elimination and detecting accuracy improvement.The results show:(1) Propagation effect makes larger high value areas of echo power ratio around the receiver radar than by the side of the main radar in bistatic radar system; moreover, propagation effect has relationship with the polarization of incident electromagnetic wave.(2) The specific value of the effective volume for bistatic and monostatic polarization radar system sampling is same to the derivative of Rt (polar axis length of the main radar in bistatic radar system) and a (half length of the long axis of the oval). (3) According to the equations we derived in this paper, with the given distance of2f, main antenna azimuth (expressed as Φ) and emit wave radial transmission distance (Rt), the size and spatial location of effective volume of bistatic radar, corresponded to the received echo, can be determined. |
