Practical Homing Guidance Law for Impact Angle Control of a Re-entry Vehicle with Limited Maneuverability

This paper proposes a practical homing guidance law for impact angle control of a re-entry vehicle. Conventional guidance laws for re-entry vehicles has suffered from high complexity in implementation and degradation of their performance when there exist large initial errors. To address this issue, diveline vector is introduced for desired impact angle and used to derive the guidance command. Afterwards, the derived guidance command is incorporated with typical proportional navigation (PN) guidance command for homing to balance between the homing and diveline alignment. The proposed guidance law makes the vehicle align with the diveline vector first, and then home on the target along the diveline vector, working as mid-course guidance law and terminal guidance law simultaneously. Computer simulation shows that the proposed method has superior performance even when there are large initial range errors and impact angle errors.