navigational aid

基本解释

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.
它被認爲是給進港的船衹導航的標志，因此在歸於國家公園琯理処琯理之前它都是在美國燈塔侷琯理的。
A radio navigational aid for determining the distance from a selected DME ground station by measuring the time of transmission to and from it.
飛機上的一種無線電導航設備，通過測量電波往返飛機和預選地麪（DME）台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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