Abstract: A method and system for covertly determining and predicting air-to-air target data relative to a predetermined position passively senses the target (84) to produce a passive target data set. Next, the method and system transform (14) the passive target data set to produce a transformed passive data set. Then, the system compares (22) the transformed passive data set to a predicted data set (20) to generate a measurement error. By actively sensing (38 and 40) the target for a minimally detectable period (42) of time to produce an active target data set (28), the system applies constraints (28) and therefrom computes penalties (26) that relate to the measurement error (22) to produce a system error. Then, in response to the system error (24) the method and system compute the direction (30) and magnitude (32) for a perturbation or a response (44) to the predicted target data (18).