Control system, lithographic projection apparatus, method of controlling a support structure, and a computer program product

A method of controlling a support structure in a lithographic apparatus comprising:

• providing an object to a support structure arranged to support the object;
• measuring a position of the object in a first coordinate system using a first measurement system;
• measuring a position of the support structure in a second coordinate system, the first measurement system having a presumed position in the second coordinate system;
• converting the measured position of the object into a converted position of the support structure in the second coordinate system;
• performing a first positioning of the support structure in a manner dependent upon the measured position of the support structure, the converted position of the support structure, and a position error signal indicative of a difference between the presumed position and an actual position of the first measurement system in the second coordinate system;
• determining the actual position of the first measurement system in the second coordinate system using the presumed position and the position error signal;
• and
• determining the converted position in a manner dependent upon the actual position of the first measurement system and the measured position of the object.

A computer program product embodied in a non-transitory machine-readable medium, said computer program product being encoded with instructions for performing, when executed by a processor, a method of controlling a support structure in a lithographic apparatus, said method comprising:

• providing an object to a support structure arranged to support the object,
• measuring a position of the object in a first coordinate system with a first measurement system,
• measuring a position of the support structure in a second coordinate system, the first measurement system having a presumed position in the second coordinate system, converting the measured position of the object into a converted position of the support structure in the second coordinate system,
• performing a first positioning of the support structure in a manner dependent upon the measured position of the support structure, the converted position of the support structure, and a position error signal indicative of a difference between the presumed position and an actual position of the first measurement system in the second coordinate system.;
• determining the actual position of the first measurement system in the second coordinate system using the presumed position and the position error signal;
• and
• determining the converted position in a manner dependent upon the actual position of the first measurement system and the measured position of the object.