Use a tiny, chirped burst that sweeps a narrow slice of the band, then wait for the echo. Keep the sweep low‑power so it slips under the radar of most noise sources. Put a few omni antennas on a phased array, record the time‑of‑arrival and phase at each feed, and triangulate with least‑squares. Apply a matched filter tuned to the chirp shape to squeeze out the background—it's like hearing a whisper in a crowded room. Use a narrowband notch to suppress any strong carrier you already know about, then do a simple adaptive cancel: subtract a running average of the background. The trick is to keep the bandwidth tight and the signal short; a single pass of the sweep is enough to map the field, so you never waste channel time. And if the noise still plays tricks, just crank the chirp's frequency resolution up a notch. That’s the low‑profile move.