Mystery Signal from a Helicopter Filming a Police Chase
Self-taught signals and electronics hacker, Oona Räisänen was watching a raw clip from a news helicopter capturing a police chase. She noticed an interference in the audio, which turned out to be a mysterious digital signal. What she discovers is really quite interesting!
What could it be? Location telemetry from the helicopter? Information about the camera direction? Video timestamps?
The first guess seems to be correct. It is supported by the relationship of two of the three byte groups. If the 4 first bits of each byte are ignored, the data forms a smooth gradient of three-digit numbers in base-10. When plotted parametrically, they form an intriguing winding curve. It is very similar to this plot (see above) of the car’s position (blue, yellow) along with viewing angles from the helicopter (green), derived from the video by magical image analysis (only the first few minutes shown)….