What is the use of microcontroller in cruise missile?

Answer 1

There ar two answers to this question. The one I can give you is that a microcontroller in any machine like a cruise missile needs to steer its way from where it is launched to where it is supposed to hit a target. The answer I cannot give involves the details on how that steering is done.

Modern cruise missiles use microcontrollers for two major functions: "mid-course" guidance, and "terminal' guidance. Mid-course guidance is generally done via either inertial methods (gyroscopes linked to the microcontroller), GPS (or similar radio-frequency triangulation), or TERCOM (terrain matching using a radar altimeter compared to a internal map of the path the missile should take). For terminal guidance (i.e final target designation/discrimination within the last 10 seconds of flight or so), this is typically done via optics (an on-board video camera doing computer vision matching against the expected target profile), radio-emission homing, or laser homing. In all cases, the microcontroller is required to take the input from the relevant sensor and determining three things: (1) where the missile currently is (2) where the target is supposed to be, and (3) the proper flight course corrections to make sure the flight path takes it from the current position to the target. For various reasons, the technology of microprocessors currently used in such missiles is usually 5-10 YEARS behind state of the art in the commercial world, so it's pretty amazing the things that can be done using such outdated Cpus.