A Quantum Illumination Ranging Head for Navigation in Clutter

Detecting and ranging a weakly reflecting object in bright background clutter is a problem where classical signals struggle, because the background overwhelms the return. Quantum illumination offers an advantage in exactly that regime: an entangled signal-idler pair retains correlations that survive loss and noise which destroy the entanglement itself, and those correlations improve the error exponent of detection. This paper designs a quantum illumination ranging head for short-range navigation in clutter and computes its operating point. At signal brightness 0.05 photons per mode and background of 20 photons per mode, the quantum receiver's error exponent exceeds the best classical one by a factor of 4.0, the ideal 6.0 dB advantage. The paper is explicit that this is an error-exponent advantage in a specified regime, not a general superiority, and that practical receivers capture only part of it. The head is a simulated design; no target was ranged.