A lithography apparatus and device manufacturing methods are disclosed. A lithography apparatus includes a support stage, and a measurement system including a sensor part and a reference part, the measurement system being configured to determine the position and/or orientation of the support stage, or of a component mounted on the support stage, relative to a reference frame by using the sensor part to interact with the reference part, wherein: the reference frame comprises N sub-frames coupled together so as to behave predominantly as a single rigid body with respect to vibrations below a first reference frequency and predominantly as an N-body system with respect to vibrations above a second reference frequency, where N is an integer greater than 1.