Density, Not Distance: Clustering Pulses Into Emitters

Grouping pulses into emitters sounds like drawing a box: same frequency, same bearing, same pulse width — same radar. That works until two radars share a band, or one hops across your gate, and then the box quietly lies. We walk through density-based clustering the way it actually gets implemented — core distance, mutual reachability, a minimum spanning tree, and a robust cut threshold — then score the resulting emitter candidates honestly and hit the O(n²) wall that shapes the whole pipeline.