Weighted Two-Dimensional Root MUSIC for Joint Angle-Doppler Estimation With MIMO Radar

For jointly estimating angle-Doppler information, two-dimensional multiple signal classification (MUSIC) is often applied, which requires an exhaustive grid search over angle-Doppler domain. To mitigate the computational complexity and enhance the estimation performance, we modify two-dimensional MUSIC in three steps. First, instead of using two-dimensional spectral search, it is converted to two consecutive polynomial root-finding problems. Second, the degree of the polynomial in the first root-finding stage is undesirably high in general; hence, we approximate it to a lower order polynomial through discrete Fourier transform. Finally, further enhancement can be achieved by having the closest approximation of null-spectrum function by assigning unequalweight coefficients. Cramer-Rao bound is derived for joint angle-Doppler estimation as a benchmark in our performance analysis.