Malaysian authorities revealed later that military radar had tracked the plane as it turned back to the west and flew across the Malaysian Peninsula, up the Strait of Malacca, before flying out of radar range at 2:14 a.m. and vanishing once again.
For the PLA, anti-missile systems, Aegis-class guided-missile cruisers, near-top-of-the-line F-16s fitted out with the latest air-to-air missiles, "over-the-horizon" long-range radar - all of this equipment is either in Taiwan, on its way or "under consideration" - are threats that can be coped with militarily.
Each Global Hawk has infra-red and radar sensors, and a surveillance range of 100 miles.
Controlling planes over oceans presents all kinds of challenges because aircraft are out of normal radio and radar range.
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These systems use camera images or near-range radar to determine the direction and position of the vehicle in relation to lane markings.
Utilizing four short-range radar sensors (two at the front, two at the rear), one long-range radar and a stereo camera, the vehicle is capable of cruising down an open freeway as well as negotiating heavy rush-hour traffic.
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The prize was an offer to give Cuba more than 100 tactical nuclear weapons that had been shipped to Cuba along with the long-range missiles, but which crucially had passed completely under the radar of US intelligence.
But radar can be blinded by bad weather, and not all volcanoes are within range of suitable equipment.
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There is a second advantage to using lasers in preference to radar: while they have a similar range, laser sensors have a significantly wider field of vision.
This includes cancelled deployment of two destroyers equipped with Aegis missile defense systems, along with terminating delivery of a second TPY-2 phased-array X-band long-range missile defense radar system for Japan.
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In the cases they present in their report, all conventional explanations of something natural or man-made had been eliminated by the authors and their associated teams of experts, and yet these objects were observed at close range by pilots, tracked on radar, and officially photographed.
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The Bush-era proposal called for the United States to set up a radar site in the Czech Republic and 10 missile interceptors in Poland to counter the threat of Iran launching long-range missiles at America's allies in Europe.
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