ASSET: a software tool for the evaluation of manoeuvre capabilities of highly agile satellites

Abstract

The new generation of agile earth observation satellites provides much higher observation capabilities than their non-agile predecessors. From a kinematic point of view, these capabilities result in more complex guidance laws for the spacecraft’s attitude control system. The computation of these guidance laws is driven by a number of factors. For instance, the Earth’s curved shape and its rotation in combination with the possible scan path geometries lead to a highly nonlinear relation between the motion of the satellite and the line-of-sight projection onto Earth. In this paper ASSET (Agile Satellites Scenario Evaluation Tool) is presented. ASSET is a modular MATLAB command line tool developed at Astrium GmbH, Germany, to asses the manoeuvre capabilities of agile satellites carrying time-delayed integration instruments. Each single scenario may consist of one or several ground scans, linked by suitable spacecraft slews. Once the entire scenario is defined, ASSET will analyse whether the kinematic and dynamic constraints of a specific satellite allow this scenario to be performed and will then generate the related guidance profile (angles and angular rates). The satellites’ ground track, the projection of the instruments line-of-sight, and the projection of the instruments field of view onto the earth can be plotted for a visual inspection. ASSET can perform the analysis of scenarios with several different scan modes usually performed by this type of satellite.