franken_doppler_finder (fdop)

Give fdop a recording, the day it was made and a rough US region. It finds the propeller aircraft you can’t hear in it, fits their Doppler curves, matches them against archived ADS-B flight tracks, and returns a latitude and longitude, a confidence radius, a map, and the nearest town and ZIP code.

git clone https://github.com/Dicklesworthstone/franken_doppler_finder && cd franken_doppler_finder
cargo build --release                  # rustup fetches the pinned nightly from rust-toolchain.toml
./target/release/fdop selftest         # offline known-answer run on a synthesised recording (needs ffmpeg)
./target/release/fdop locate clip.m4a --dates 2026-09-08 --near "NY"

A recording with no GPS tag and nothing recognisable in frame usually still carries the drone of light aircraft passing kilometres away. Each pass leaves a falling tone whose shape fixes the aircraft’s speed and its closest distance. Two passes, with their real time gap, fix a place and a clock. Public ADS-B archives record where every transponder-equipped aircraft was, second by second. fdop automates the whole chain, from finding the faint curves in a…