Complex sentence: The missiles were originally steered by joystick control i.e. Manual Command to Line of Sight (MCLOS), later updated to the Semi-Automatic Command to Line of Sight (SACLOS) system where the controller merely sights the target.
Split into simpler sentences: The missiles were originally steered by joystick control using manual command to line of sight (MCLOS). This was later updated to the semi-automatic command to line of sight (SACLOS) system where the controller merely sights the target.