CINRAD WSR-98D and its ground clutter filter design

Based on the US NEXRAD WSR-88D Doppler weather radar, Beijing Metstar Radar Co., Ltd. ( A China-US joint venture) has designed a successor product - the CINRAD (China New Generation Radar) WSR-98D. The two systems have comparable overall performance. However, taking advantage of advances in the electronics industry in the last decade, it was able to re-implement the radar signal processor, along with all the central timing and control functions that are unique for the NEXRAD design, into just three PC style plug-in boards. Its processing capability is almost twice compared to the NEXRAD´s signal processor. With extensive use of VLSI DSP and PLD devices, this is an open system based, highly scalable and re-programmable design that can easily be upgraded as the need demands. The objective of the ground clutter suppression capability is to improve the measurement of weather return parameters in the presence of clutter. The CINRAD WSR-98D ground clutter suppression function consists of the following: (a) clutter filter; and (b) clutter map. The filter is a fifth-order elliptic high-pass filter operating on each 250 m range bin independently. For each range bin, the input time series consists of samples occurring at the PRF rate