radio frequency spectrum短语¹⁸⁰⁰⁹⁸⁺¹ 基本例句 射频频谱 Hyperbolic navigation systems were first implemented as ground-based navigation systems operating in the medium and long-wave radio frequency spectrum like LORAN, DECCA or OMEGA. 双曲导航系统首先在陆基导航中得到应用，他们工作在中波或长波段，如 LORAN、 DECCA和 OMEGA。 www.astronomy.com.cn