Abstract: The guidance systems based on separately the designing of the estimator and the guidance law have not been suboptimal. This paper addresses the problem of guiding a missile towards an evading agile target in the presence of noisy measurements. A new guidance law that complies with the optimal estimator under the guidelines of the GST is proposed. The conception of miss-set is termed and a geometric approach is utilized. As a result, The new cooperative guidance law is designed. The numerical simulation for a realistic engagement scenario demonstrates the performance and viability of the proposed method.