Optimal coupled guidance laws against three dimensional helix maneuver

Interception of target that is performing a three dimensional barrel roll maneuver-helix trajectory is dealt with. The existing approaches are dealing with the guidance in three dimensional coordinates frame as three separated-independent problems. This representation of the trajectory assumes no coupling between the axes. However the equations of motion in the three axes of a barrel roll maneuver-helix are coupled. Two representations of barrel roll maneuver-helix trajectory that exploit this coupling are presented, the partially-coupled (PC) and the strongly-coupled (SC) representations. A rotating acceleration vector representation is used to describe the helix trajectory. This representation is used to derive guidance schemes, an estimator and a guidance law. The performances of the coupled representations are compared to the performance of guidance law based on the no-coupling (NC) representation. Simulation results compare the RMS miss distance and control effort of the different representations. It is shown that the usage of guidance laws that take into account the coupling leads to improved performance.