Developing accurate missile guidance systems has been a quest of military powers since World War II. To come up with the most lethal attack weapon, defence researchers around the world have experimented with myriad technologies ranging from heat-seekers or infrared (IR) sensors, radar systems and thermal imaging to laser.
Surface-to-air missiles (SAM) have again caught the world’s attention after the tragic crash of Malaysia Airlines Flight MH17 in Ukraine.
Heat-seeking missiles have two major components. A radar system—which can either have a single or multiple radars—is stationed on the ground. On the top of that, the missile has a heat-seeking system, such as an infrared sensor, on its tip, which can identify infrared rays emitted by the targeted plane.
Even as the radar sends the missile information on the target’s initial location, the target itself is moving. Its coordinates change continuously. “These missiles are intelligent systems that can adjust, readjust their position based on the continuous inputs provided by the radar,” said Ajey Lele, a senior research fellow at the Institute for Defence Studies and Analyses (Idsa), a New Delhi-based think tank. “Once shot in a predetermined direction, a heat-seeking missile can do a self-course correction of its trajectory based on the radar signals sent from the ground.”
IR rays are electromagnetic radiations that are emitted depending upon the temperature of a particular object—the hotter the object, the stronger the infra red radiation. Since the temperature at high altitudes, such as 32,000 ft, is significantly low, radiations emitted by the target are immediately spotted by the missile. Combining the information from radar and IR sensors, a heat-seeking missile is able to pinpoint the target. “The tracking radar tracks the trajectories of the missile as well as the target object. The missile gets coded information from the radar guiding it to reach the target,” said Ravi Kumar Gupta, a senior scientist at DRDO.
Finally, after it has locked on to the target, there is a predetermined proximity fed into the missile’s on board computer. “As soon as the missile comes within that proximity, a ‘proximity fuse’ gets activated and the warhead in the missile explodes to destroy the target,” Gupta added.
nikita.m@livemint.com
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