Micro-Doppler signatures of helicopters in multistatic passive radars

This study presents an analysis of micro-Doppler signatures of helicopters obtained using a network of passive radar receivers utilising multistatic geometry. In the multistatic scenario, for each passive radar receiver the target is visible from different bistatic angles, which results in different micro-Doppler signatures. This feature allows additional information on the observed helicopter target to be obtained. The presented concept has been successfully verified by the authors using the real micro-Doppler signatures of a helicopter collected during the measurement campaign. As an illuminator of opportunity for the passive radar network a commercial digital video broadcasting-terrestrial (DVB-T) transmitter was used. The results of the applied micro-Doppler analysis for the real multistatic passive radar measurement carried out are presented in this study. In addition, some examples of inverse synthetic aperture radar (ISAR) images of helicopter rotor blades based on micro-Doppler analysis in the multistatic configuration are shown in this study.