The instrument model: performance prediction simulator for SIM PlanetQuest - art. no. 667509

The SIM Instrument Model performs single tile simulations for the SIM Instrument. It provides a tool to combine the effects of errors in the different subsystems such as the science interferometer, guide interferometer, external metrology sensor, and roll sensor. The inputs to the Instrument Model are the sensor errors for the internal instrument measurements. These errors can be derived from testbeds or other physical models. The Instrument Model perturbs ideal sensors and replicates the fundamental SIM processing called delay regularization. This process reconstructs the science interferometer measurements by using additional sensor measurements. The output of the Instrument Model is the regularized delay, which is the principal science measurement for various observing scenarios such as Wide Angle Grid, and Narrow Angle observations. The primary role of the Instrument Model has been single tile performance prediction but it also serves as variety of different system engineering activities such as validation of the SIM Astrometric Error Budget, demonstration of SIM's capability for picometer sensing for the SIM Technology Milestone 8, development of instrument calibrations, analysis of system level errors, and validation of the averaging approach for the science data processing. The Instrument Model will continue to be an integral part of the SIM modeling plan to predict single tile performance for the SIM mission.