Complex sentence: The pitchover angle varies with the launch vehicle and is included in the rocket's initial guidance system, for some vehicles it is only a few degrees while other vehicles use relatively large angles (a few tens of degrees).
Split into simpler sentences: The pitchover angle varies with the launch vehicle and is included in the rocket's initial guidance system. For some vehicles it is only a few degrees, while other vehicles use relatively large angles (a few tens of degrees).