Synchronous Two-dimensional Spatial Polarization Encoding Laser Beam Riding Guidance Technology

A system for providing signals that are indicative of a missile's position across a laser beam is described. The beam rider guidance system comprises a transmitter for transmitting beam that is encoded by the modulators such that the polarization state of the beam varies across the beam, and a receiver that responds to the polarization of the received energy to provide signals indicative of the relative position of the missile within the beam. In order to realize real-time guidance, a means of encoding the two dimensions of the beam synchronously at a different modulation frequency was invented. And that the position determining measurement is substantially independence of rotation is proved. The emphasis of the paper is to study and compare the devices suitable for polarization encoding. Three kinds of crystal's phase lags by the action of electric field on the basis of Pockels effect were studied. The principle of the modulator based on electro-optic effect is introduced. A modulator made up of Lithium Niobate(LiNbO3) crystal was designed.