Gain projection geo-location systems and methods

A system for estimating the geographic location of a Radio Frequency (RF) emitter, comprising:

• a beamforming antenna array exhibiting multiple overlapping beams for spatially filtering and receiving RF signals;
• a plurality of synchronized receivers for detecting and measuring a time-of-arrival and an amplitude of signals received in each beam;
• a Global Positioning System/Inertial Navigation System (GPS/INS) module for determining the position and attitude of the antenna array at the time of signal reception;
• and
• a processor for identifying simultaneous detections of an emitter which have occurred in adjacent beams, projecting beamformed antenna gain patterns onto the underlying terrain for all instances of a simultaneous detection in adjacent beams, weighting the projected patterns, accumulating the weighted patterns to form a Maximum Likelihood Surface (MLS), and estimating the location of the emitter through analysis of the resulting MLS.

A system for estimating the geographic location of a Radio Frequency (RF) emitter, comprising:

• a detection search module effective to receive time-stamped amplitude measurements of signals received in different beams of a beamforming antenna array and identify simultaneous detections of an emitter having occurred in adjacent beams as Simultaneous-Adjacent-Balanced (SAB) signal pairs;
• a search grid generation module effective to extract a search grid of localized terrain elevation over which the emitter is expected;
• a projection module effective to project beamformed antenna gain patterns onto the search grid when a simultaneous detection in adjacent beams is identified;
• a weight and accumulate module effective to receive the projected gain patterns, weight each projection based on the associated amplitude measurement, and accumulate the weighted projections to form a Maximum Likelihood Surface (MLS);
• and
• a peak search module effective to determine a peak within the MLS and output geographical coordinates associated with the peak.