Attitude performance requirements and budgeting for RASAT satellite

Pointing error budget calculations are considered for RASAT satellite. RASAT is designed to point its payload, an optical camera, in a desired direction within specified limits and maintain this direction via attitude determination and control. These limits are decided by attitude performance requirements, which are dependent upon top-level pointing and mapping requirements. The budgeting process takes into account possible errors appropriately, so that their cumulative effect would not exceed the imposed requirements. In an effort to cover the desired area and achieving the mission objectives, the total error made in the pointing has to be minimized. The first step in this effort is to build a pointing error budget to identify and manipulate possible sources of errors. Fundamental concepts are defined in prescribing attitude performance for satellite pointing and mapping. Then, error budgeting is detailed and a tool developed for executing the pointing budget is presented.