The earth's rotation and its motion around the sun add an appreciable frequency shift. 地球自转与地球绕日公转产生附加的频移。
The Brillouin frequency shift can be precisely measured by changing the local frequency and adopting narrow filter. 通过改变本地电信号的频率对信号进行扫描和窄带滤波，从而实现了布里渊频移的精确测量。
