Adaptive Nulling with Multiple-Beam Antennas
Abstract
This technical note discusses some of the more prominent features of an adaptive nulling algorithm when used in conjunction with a multiple-beam antenna operating over the earth field of view at synchronous altitude. A brief discussion of some of the basic properties of the multiple-beam antenna configuration used in the study is presented, following which some of the characteristics of the conventional LMS power minimization algorithm, such as the Applebaum-Howells type, as they apply to the multiple-beam antenna are developed. The relationship of the adapted radiation pattern to radiation pattern synthesis techniques is discussed. Next the time required for the algorithm to adapt to the steady state solution is considered. For the LMS algorithm, the dynamic range of interference power levels to be nulled sets the dynamic range of adaption times required by the adaptive algorithm. This spread in adaption times is related to the spread in the eigenvalues of the interfering-source correlation matrix defined at the receive ports. Techniques for compressing this eigenvalue spread, and hence increasing the dynamic range of the algorithm, are determined.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1976
- Accession Number
- ADA034652
Entities
People
- Joseph T. Mayhan
Organizations
- Massachusetts Institute of Technology