The definition of the issue of guiding projectile is to find a appropriate flight path to reach its target. The “smart” projectile can defined as a guided flying device. In order to provide a successful flight of a projectile, three different systems represented by: guidance system, navigation system and control system should work and run with each other. The task of the guidance law which is a branch of the guidance system is to decide what steps should be taken to reach the target. There are different guidance law that each lead to different paths for the projectile to hit the target. The criteria for a suitable guidance law are: minimization of lateral acceleration, the time to collision, miss distance, impact angle and low sensitivity to noise. The projectile actuators have saturation that leads to constraint the lateral acceleration. Also, navigation sensors are limited in measuring the lateral acceleration of the projectile. Hence, The guidance law for smart projectile is designed by taking into consideration the constraints of the lateral acceleration. Assuming that the target is moving, the velocity and the acceleration of the target are indeterminate but bounded and their upper bound is known. Also, the presence of wind on the projectile path, is considered as a disturbance to the projectile, in which the wind speed is indeterminate but bounded, and its upper bound is know. Hence, the design of a robust guidance law can be a good choice, because of its good robustness to external disturbances and the uncertainty of the target informations.In this thesis, a non-linear robust guidance law is proposed for interception of moving targets in the presence of limitation in the lateral acceleration of a smart air-to-surface projectile. Auper-twisting second-order sliding modeguidance law is alsousedto reduce thechatteringof the guidance law. Numerical simulations and Processor in the loop simulation are implemented to demonstrate the effectiveness of the proposed guidance law. Key Words: 1- Smart projectile 2- Nonlinear robust guidance law 3- Constraint of the lateral acceleratio