双基地天气雷达系统的有效照射体积

Effective sampling volume for bistatic weather radar system

根据"有效照射体"的基本概念,采用微分理论来回避椭球面近似为平面的假设,推导了双基地雷达系统有效照射体积表达式,证明双基地雷达系统有效照射体积与单基地雷达有效照射体积之比值Vb/Vm,在数值上等于双基地系统主站极轴长度Rt相对于半长轴长度a的导数.有效照射体积数值计算结果与以往相同,放宽了推导过程中的假设条件,显得更加严谨、易懂.还给出了双基地雷达系统各几何量(如Vb/Vm、Rt、主站共面方位Φ、辅站极轴长度Rr、辅站共面方位Φr、双基地角β)之间的一些关系式,分析了在双基地雷达系统探测过程中有效照射体积随有关量变化的特征,为双基地偏振雷达系统天线控制、资料处理、旁瓣影响分析、探测精度提高等提供理论依据.

In order to avoid the approximation of spheroid surface as flat plane in calculation of sampling volume,the differential theory is applied to derive the expression of effective sampling volume for bistatic weather radar system.It is proved that the ratio of the bistatic resolution volume to the monostatic resolution volume,or Vb/Vm,numerically equals the derivative of the polar axis length （Rt） to the semi-major axis length （a） in the bistatic radar system.Though the result from numerical calculation for sampling volume is the same as that from references,approximations performed to obtain the expression has been eased and the derivation process is theoretically strict and easy to understand.Some relationship expressions between the geometric elements for bistatic polarization radar system,such as the ratio Vb/Vm,the radius Rt and co-plane azimuth Φ for the transmitter,the radius Rr and co-plane azimuth Φr for the receiver,and the bistatic angle β,are obtained.The features of effective sampling volume variation with the related geometric elements are analyzed.The results provide a theoretical base for bistatic polarization weather radar antenna control,data processing,sidelobe contamination elimination and detecting accuracy improvement.