Transfer alignment problem: Algorithms and design issues

Transfer alignment is the process of initializing the navigation sensors of tactical guided munitions launched from a platform. Through this method the misalignment between aligning and aligned body is estimated, which facilitates navigation of aligning system during its post-ejection course of flight. Measurements provided by navigation sensors of aligning system are noisy compared to those of the launch platform. Thus, excitation of the platform in the form of some deliberate manoeuvre is important in order to discriminate the signal from noise in the available measurement so that the misalignment can be effectively estimated. With advancement of technology, the prerequisites of accurate alignment have changed and with it the algorithms have also undergone continuous transformations. Extensive work has been done on this topic over the years. Here a detailed review of the evolution of transfer alignment problem has been presented. Emphasis is on statistical and algorithmic aspects of the problem rather than time line of work already done. This review provides a general guideline for new entrants to this field and should help practitioners with information regarding trends of research on this topic.