Implementation and results of an RCS measurement system in CATR

This paper describes the development of a fully automated measurement software for Radar Cross Section (RCS) measurements in a Compact Antenna Test Range (CATR). The measurement hardware includes an Agilent network analyzer for transmitting and receiving the microwave signals and a positioner controller to control the motion of the Styrofoam column. The software is designed to control a variety of microwave transmitter / receivers and two axis positioner controllers through the standard General Purpose interface bus (GPIB) interface. Addition of new Network Analyzers is supported through a slight modification of hardware control module. The measurement process includes calibration of CATR with a standard target e.g. aluminum sphere followed by RCS versus angle/frequency measurement of the Target Under Test (TUT). A Time-domain gating algorithm is implemented to remove the unwanted reflections and get the isolated response of TUT. The gated response of the TUT is compared with the calibration data to obtain the desired results. The data acquisition and processing is implemented in Agilent Visual Engineering Environment (VEE) and MATLAB. A variety of experimental measurements with aluminum Spheres and rectangular plates were performed to validate the accuracy of the software. A comparison of results with theoretical as well as existing commercial softwares is presented and the measured results are found to be within 0.2 dBsm.