Over on his blog DE8MSH has uploaded a video showing a timelapse of some Doppler signal reflections he recorded. He shows more information about his Doppler recording setup on this previous post which shows that he was even able to get a Doppler reflection from the ISS using the French Graves radar.
When an airplane or meteor reflects a signal from a strong transmitter such as an ATIS signal or the Graves radar in France, the received reflected signal frequency will change as the plane or meteor comes towards or away from your receiver. This is due to the Doppler effect. Its effect can be observed as the sloping lines shown in the video.
To do the recording, DE8MSH used HDSDR together with spectrum lab and an RTL-SDR.