Passive RF, single fighter aircraft multifunction aperture sensor, air to air geolocation

This invention helps a fighter jet secretly find and follow enemy aircraft without giving away its own position. It uses the jet's existing radio sensors to listen for signals from other planes and then applies complex mathematical methods to figure out how far away and where the enemy is, even if they are moving. The claims narrow this to specifically using a two-stage process called ML-PDAF for initial detection and IMM for continuous tracking, and in one version, only using azimuth measurements from the jet's passive RF sensor combined with specific flight maneuvers.