Optical jitter effects on target detection and tracking of overhead persistent infrared systems

Abstract

The purpose of this thesis is to provide a system level performance analysis for an imaging spacecraft. In an imaging spacecraft, an attitude control subsystem’s function is to orient the spacecraft’s body to acquire a target through the use of an actuator. In practice, reaction wheels commonly perform this function by producing a reactive torque on the spacecraft. Consequently, due to the static and dynamic imbalances in individual reaction wheels, an undesired vibration, called jitter, is generated during operation and causes variations in the spacecraft’s attitude. Focusing on missions and payloads operating in the infrared band, optical jitter effects on target detection and tracking performance need to be investigated. Using a quaternion error feedback design, jitter produced by the reaction wheels was recorded while performing a standard spacecraft maneuver. Simulating a low earth orbiting satellite, the vibrations generated a significant optical jitter blur due to a line-of-sight motion. After implementing the optical jitter blur in a baseline high resolution image, the simulation considerably reduced the frame’s spatial resolution and intensity. The simulation demonstrated the jitter blur’s effects on spatial resolution and intensity, which significantly decreased the system’s ability to detect and track objects-of-interest.