Estimation of line-of-sight rate in a homing Missile Guidance loop using optimal filters

The concept of noise is very important in a Missile Guidance system. In radar homing tactical missile the seeker measurement of line-of-sight (LOS) rate signal required for the implementation of proportional navigation guidance is not perfect, but it is corrupted by noise. To extract the signal from the measurement an understanding of the concept of noise and its various properties will be analyzed in this paper. Therefore in order to derive the line-of-sight rate estimate required by proportional navigation guidance, it is necessary to use a digital noise filter in an onboard missile guidance system. These filters are constant gain filters known as fading memory filters to derive the line-of-sight rate estimate. By considering various cases and simulation trails some of the properties of digital fading memory filters and their influence on system performance will be investigated in this paper as these fading memory filters will serve as the foundation for more advanced digital filters known as Kalman filters. This paper brings forth an approach to estimate and smooth the LOS rate and also to estimate target maneuver by using second and third order fixed gain filters.