X 波段一维扫描有源相控阵天气雷达测试定标方法

摘要

该文根据有源相控阵天气雷达的体制特点，参考多普勒天气雷达测试定标方法，提出了一维扫描有源相控阵天气雷达的测试和定标方法，将测试重点放在天馈系统、T／R 组件、脉冲压缩、动态范围的测试和定标上，以解决不同观测模式、不同波位的天线增益等参数变化引起的回波强度测量误差问题。测试结果表明：天馈系统在不同观测模式下的天线参数随仰角的变化情况、波束指向的准确度、T／R 组件的动态范围等均符合设计要求，回波强度和径向速度定标精度较高。雷达经过测试和定标后，于2014年5—8月分别在安徽定远和四川甘孜进行外场试验，并与附近多普勒天气雷达（SA）和 C 波段双线偏振雷达观测数据进行对比，结果表明：回波强度误差在合理范围内，精细测量、警戒搜索、快速观测3种模式观测的强回波的水平和垂直位置、结构和系统误差均比较一致，数据可靠。%A mobile X-band phased-array meteorological radar (XPAR)is developed by State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,and Anhui Sun-create Electronics Limited Company.The XPAR scans electronically in elevation while scanning mechanically in azimuth,transmits radar wave with wide beam width (about 20°in vertical direction and 1°in horizontal direction)and re-ceives 14 beams simultaneously.As reflectivity calibration is key technique for the active phased-array ra-dar application in meteorological observation,the testing and calibrating method for the XPAR is investi-gated according to characteristics of the transmitter/receiver (T/R)the multi-beam work mode.The test and calibration focus on the antennas,T/R,purse compress and the variations of gain and beam width with the angle of the antenna beam in respect to the normal of the array face,in order to reduce the obser-vation bias introduced by different modes.After calibration,the XPAR is used to observe 3-D structures and evolutions of convective precipitation in field experiment at Dingyuan of Anhui Province and Ganzi of Sichuang Province from May to August in 2014.The data of an S-band operational radar (SA)and a C-band polarization radar (CPOL)nearby are used to examine the observation capability of the XPAR.Re-sults show that the antenna gain and its variation with the scanning angle,the beam direction,dynamics ranges of T/R are in conformity with the design.The transmitter and receiving characteristics for 128 T/R are similar.The calibration bias for reflectivity and radial velocity measurement are less than 0.98 dB and 0.1 m·s-1 ,respectively.Variations of T/R parameters in observation are watched and corrected by the correcting network.Comparing with the SA and CPOL,the bias of reflectivity in Fine Mode is less than 1 dB,the biases for Guard Mode and Quick Mode are less than 2 dB,and the velocity observed in three modes are accordant very well.The bias of reflectivity and radial velocity by XPAR are reasonable.The horizontal and vertical structures of precipitation observed by 3 radars are similar.And calibration results provide basis for quantitative measurement of the XPAR.