Simultaneous target flying mode identification and altitude estimation in bistatic T/R-R HFSWR

High frequency surface wave radar (HFSWR) cannot detect target altitude directly and is unable to identify flight mode. Assuming that the estimation and identification processes are mutually dependent, an integrated method called simultaneous identification and estimation (SIE) is proposed by applying a two-level multiple model approach to the flight mode probability mass function (pmf) and state probability density function (pdf) simultaneously. The SIE involves two altitude estimation mode-conditioned model sets, which are established utilizing the variation property of the propagation attenuation at different flight modes. The multiple model approach incorporated in SIE is different from the traditional interacting multiple model (IMM). It is applied at two levels: within each mode-conditioned estimation model set and across all the mode-conditioned estimation model sets. Simulations and real trials demonstrate the performance of the proposed SIE method.