Feedback Nulling Demonstration System Hardware.
Abstract
As part of the technology development of anti-jam satellite communications, Lincoln Laboratory has developed, built, and tested a demonstration analog-feedback adaptive-nulling antenna system. The system, which is based on the Howells-Applebaum feedback loop, is designed to increase the signal-to-interference ratio when desired signals operate in the presence of interference signals. The signals received from interfering or undesirable signal sources are minimized by appropriately modifying the antenna radiation pattern so as to attenuate signals from the direction of those sources relative to the desired signals. The demonstration system consists of a simulated array of antenna elements and uplink signals and a real-time adaptive receiver-processor which controls the weighting of each element signal prior to combining. The weighting process involves changing the relative amplitudes and phases of the received signals thus changing the effective receiving radiation pattern of the antenna, i.e., its relative response to signals arriving from different directions. The system operation involves taking the signals from N independent antenna elements and weighting and combining them to form a single output signal in which the signal-to-interference ratio is enhanced over what it is for any individual antenna element. The task of the nulling processor is to select the set of weights for the antenna element array in some optimum fashion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 23, 1979
- Accession Number
- ADA084013
Entities
People
- Bing M. Potts
- David M. Hodsdon
- David Siegel
- Ervin S. Davis
- Howard S. Babbitt
Organizations
- Massachusetts Institute of Technology