GPS Based Navigation Accuracy Question

[Flying Binghi]

Quote -

GPS guided weapons are provided with an integral multi-channel GPS receiver and Inertial Measurement Unit (IMU) which monitors the weapon's locations and attitude to adjust its flight path to accurately impact on the target. In low cost un-powered weapons, the guidance system adjusts the weapon's free fall to hit a pre-selected point fed into the weapon prior to takeoff. GPS is also used in guided missiles and cruise missiles, for mid-course navigation.

Further info from -
GPS/INS Precision Guidance System