Application of the Frequency Response Matrix Method for an Extended Target

The frequency response matrix (FRM) method is a super-resolution technique used to locate point targets and to retrieve their reflection coefficients. This method applies a MUSIC-style subspace approach to a multistatic data matrix, which is formed by using all antenna array elements for both transmission and reception. Thus, a single snapshot of multistatic data acquisition provides richer information than its classical MUSIC counterpart. In this paper we augment the original (point target based) formulation of the FRM method so as to make it applicable to extended targets of moderate size. First we show that the same pseudo-distribution used in H. Lev-Ari and A.J. Devaney (2000) and R. Zandifar (2001) to locate point targets can still be used to obtain a reliable estimate of the location of the extended target. Then, we rely on a Taylor series expansion to construct a low-rank approximation of the acquired multistatic data matrix, and use it to estimate the target´s size and scattering amplitude (a.k.a reflection coefficient). Mathematical analysis is presented and simulation results are shown