A novel missile-to-target relative motion model for terminal guidance is placed here.Aided by precision velocity information of inertial navigation system (INS)

it overcomes the difficulties of actual inertial acceleration modeling in conventional methods.Missile dynamic was provided by on-board INS

while target maneuver was modeled as a first-order Markov process.On the resolution of velocity vector

the motion model using relative state vector was lastly proposed

which was directly applied into the constructing of a INS velocity information aided extended Kalman filter (IVIA-EKF).This filter could make full use of INS information to help suppressing seeker measurement error and enhancing precision striking.The proposed filter in missile terminal guidance was then validitied by simulation.