After months of observations, he noticed that one unidentified yet persistent source of noise was coming from the direction of the constellation Sagittarius.
经过几个月的观测之后,他注意到一个来自人马座方向的无法识别,但一直持续不断的噪声源。
3
In this case, a leading possibility is that the signal originates from an unusual modulation between a GPS satellite and an unidentified Earth-based source.