Finally, the orbital reference frame estimation of low-earth-orbit satellite is taken as an example, and the estimator of minimum variance with PSD constraint is designed and analyzed using the method proposed in this paper.
The constrained minimum variance beamforming includes directional constraints [13], derivative constraints [14], quadratic constraints [15], and soft constraints on the norm of the weight vector [16].
As described in the CRB theorem, it is sometimes possible to determine the minimum variance unbiased (MVU) estimator if the equality constraints of the CRB theorem are satisfied.
In this paper, random steering vector mismatches in sensor arrays are considered and probability constraints are imposed for designing a robust minimum variance beamformer (RMVB).
This BM can be regarded as minimum variance distortionless response (MVDR) BM as the MVDR beamformer imposes the distortionless constraint only for the desired direction.
RAB representatives include Bayesian beamformers [5, 6] and spatial filters with eigenvector constraints [7, 8], which are implemented using linearly constrained minimum variance (LCMV) filters.
To overcome the limitations of single-channel systems, various multi-channel techniques have been developed, including the minimum variance distortionless response (MVDR) [7] and the multi-channel Wiener filter (MWF) with constraints [8 12].
Improving the robustness of MVDR beamformers has commonly been achieved by adding appropriate constraints in the determination of beamforming weights, such as the linearly constrained minimum variance (LCMV) beamformer.
minimum variance distortionless response.
