Abstract: A metrology system may include an optical metrology sub-system to generate optical metrology measurements of optical metrology based on features of the optical metrology targets associated with at least one optical pitch and an additional metrology sub-system to generate additional metrology measurements of the optical metrology targets, where the additional metrology measurements have a higher resolution than the optical metrology measurements, and where the additional metrology sub-system further measures deviations of the optical metrology targets from a reference design. The system may further include a controller to generate accuracy measurements for the optical metrology targets based on the measurements, identify variations of a lithography process based on the deviations, correlate the accuracy measurements to the variations, and adjust at least one of the optical metrology sub-system, a lithography tool, or the reference design based on the correlations.