With the development of science and technology, precision-strike weapons are been considered to be important for winning victory and defending the country during war (or) attack. Laser guidance is one of the major methods to execute precision-strike in modern warfare. At present, the problems faced at the primary stage of Laser guidance has been solved with endeavors of countries. Several technical aspects of laser-beam riding guided system have been mature, such as atmosphere penetration of laser beam, clutter inhibition on ground, laser irradiator, encoding and decoding of laser beam. Further, laser beam quality, equal output power and atmospheric transmission properties are qualified for warfare situation. Riding guidance instrument is a crucial element of Laser-beam riding guided system and also in Radar-beam riding guiding system, and is also a essential element of airborne, vehicle-mounted and individual weapon. The optical system mainly consists of sighting module and laser-beam guided module. Photo detector (Quadrant detector) is the most important sensing device, and also the key to acquire the coordinate information of target space. Currently, in consideration of the 1064 nm of wavelength applied in all the semi-active laser guided weapons systems, lithium drifting silicon photodiode which is sensitive to 1064 nm of wavelength is used in photoelectric detector. Compared to Solid and gas laser, diode laser has many merits such as small volume, simple construction, light weight, long life, low cost and easy modulation.

 The present work includes the study of Various ATGM, their guidance mechanism, particularly laser beam rider guidance. Study has been carried to understand the composition and operating principle of Laser-beam riding guided system. The present work also deals with prototype development of quadrant estimation unit required for Laser beam rider guidance.