A new input estimation technique for target tracking problem is proposed, Conventional input estimation techniques assume that the target maneuver level is constant within the detection window, which has been the major drawback of the techniques, The proposed technique is developed to overcome this drawback by modeling the target maneuver as a linear combination of some basic time functions, The resulting algorithm has a generalized formulation including earlier works on input estimation. A detection performance of the proposed algorithm is analyzed by investigating the detection senstivity according to the selection of maneuver models and other design parameters such as the detection window size, measurement noise level, and sampling step size. A computer simulation study shows that the estimation performance of the proposed algorithm is comparable to Bogler's input estimation method while the computation time is greatly reduced.