Optical tracking link utilizing pulse burst modulation for solid state

Abstract

An optical tracking link and encoding technique using solid state missile acons, which easily interfaces with existing missile guidance techniques. Countermeasures hardening is accomplished without sacrifice of performance at maximum range. A solid state, missile beacon within the missile housing transmits a high frequency pulse burst of optical energy during alternate half cycles of a low frequency modulating signal therefor. The optical, modulated signal is received by an optical tracker at the missile launch site, completing an optical link between the missile and the launch site. A visual tracker at the launch site provides line-of-sight contact with a target being tracked. A guidance control for the missile responds to output signals from the missile and visual tracker and develops an error signal between the visual line-of-sight target and the direction of missile travel. Any deviation of the missile from a course of impact with the target causes an error signal to be transmitted to the missile for flight course correction. The solid state beacon includes a clock having a high frequency output thereof modulated at a sub-multiple low frequency thereof and coupled through a power driver to a GaAs, high power diode array, which generates an optical signal in response to a square wave input signal. This pulse burst modulated signal is received by a detector preamplifier of the optical tracker. A diode array in the detector is activated by the impinging optical signal and generates an electrical signal in response to the input wave. This signal is filtered and demodulated to extract the lf modulating wave therefrom. This low frequency is then interfaced with existing error detection equipment for generating a command guidance signal to the missile for error correction.