A ssr can provide more useful information than primary surveillance radar ( psr ) but is subject to the proper functioning of the aircraft s transponder 二次監(jiān)察雷達(dá)較一次監(jiān)察雷達(dá)能提供更多有用的資料,但須依賴航機(jī)上應(yīng)答器之正常運(yùn)作。
For more than 25 years , the old radar served as a primary surveillance radar ( psr ) with coverage of 200 nautical miles for en - route air traffic surveillance . it is necessary to replace the old radar because of its age and difficulty in acquiring spares 運(yùn)作逾二十五年的舊雷達(dá)為一支監(jiān)察雷達(dá),具備二百海里以內(nèi)航空交通航路監(jiān)察功能。由于舊雷達(dá)老化,及采購(gòu)該雷達(dá)的零件亦十分困難,故有需要進(jìn)行更換。