navigational aid

基本解釋

The utility model relates to a free-floating light beacon of navigational aid on water in the sea, a river, or a harbor.
本實用新型是一種海、河港口用水上助航活節(jié)式燈樁。
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Considered a navigational aid to ships entering the harbor, the statue was first administered by the U.S Lighthouse Board before eventually falling under the jurisdiction of the National Park Service.
它被認(rèn)為是給進(jìn)港的船只導(dǎo)航的標(biāo)志，因此在歸于國家公園管理處管理之前它都是在美國燈塔局管理的。
A radio navigational aid for determining the distance from a selected DME ground station by measuring the time of transmission to and from it.
飛機(jī)上的一種無線電導(dǎo)航設(shè)備，通過測量電波往返飛機(jī)和預(yù)選地面（DME）臺之間所需要的時間來確定兩者間的距離。

Some countries have laws on the books dating back centuries saying that any navigational aid certified by the government has to be controlled by that government and be based within its territorial borders.
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