The primary objective of a sensor response model is to provide object sighting messages in the form of accurate position and amplitude estimates to the tracker. This paper will examine the capabilities of a sensor response model entitled `Passive Sensor Workbench' to evaluate object sighting measurement accuracy by implementing a selected candidate sensor design and signal/image processing technique. The performance of a sensor response model is also driven by several factors external to the sensor system including the mission, threat, and environment. The mission of the sensor can vary from viewing a target from a surveillance satellite to a seeker onboard an interceptor. The threat viewed from a sensor may vary, from viewing cold targets exoatmospherically, to viewing thrusting boosters against an earth background. The environments to consider include the atmosphere, terrain, clouds, celestial bodies and nuclear effects. Each of these drivers would require a specific sensor design and signal/image processing techniques to perform within specified requirements for acquisition, detection, and track.