High-frequency(HF) skywave over-the-horizon radar(OTHR) looks down its targets from the ionosphere,it has a large operating range and a large cover areas,but it also receives strong backscatterer echoes from the terrain and sea,and interference,such as radio frequency interference,industrial interference,impulsive noise,lightning impulsive,meteor trail echoes and so on.

The modern impact on Mosuo family role;