Tracking airborne targets through windmill areas and rain clutter with ground based radar

Due to the growing number of wind farms, one of the most important tasks for ground based radars is the suppression of windmill returns which might cause spurious target detections [5]. The detection of targets in the presence of strong rain clutter would also be desirable. The usual waveform for ground based radars is LPRF (low pulse repetition frequency) with PRFs below ~1000Hz, resulting in unambiguous range measurements exceeding 150km. This waveform has many advantages for ground based radars, even with regard to clutter and small targets from near-in ground area around the radar. However, with growing signal processing capabilities, modern radars can now be extended from 3D-operation (range-azimuth-elevation) to 4D-operation (range - azimuth - elevation - Doppler). The parameters of the fourth dimension can be measured by interleaving MPRF (medium pulse repetition frequency) waveforms with the standard LPRF waveform. When targets need to be tracked through windmill areas or rain clutter, the regions concerned can be detected by an LPRF waveform. If it is predictable that one or more targets will traverse windmill or rain clutter areas, the waveform can be switched to MPRF, where targets can easier be detected in such environments.