Het gebruik van case tools bij de ontwikkeling van on-board ruimtevaartprogrammatuur

Bij het ontwikkelen van de standregelprogrammatuur voor de Italiaanse satelliet SAX is gebruik gemaakt van een aantal CASE tools. Naast een beschrijving van de standregelprogrammatuur, met als hoofdeisen een hoge mate van bedrijfszekerheid en een hoge flexibiliteit, worden de ontwikkelsituatie en de ontwikkelomgeving beschreven. Geschetst wordt...

Application of model following control and estimation techniques to attitude control of manoeuvring spacecraft Part I: Theory and simulation results

This document presents an approach to sampled data, on-board estimation and control of the attitude motion of manoeuvring spacecraft. Algorithms which are developed include: a - model following control of attitude manoeuvres b - estimation of spacecraft state (attitude, angular velocity, disturbance torque) c - optical-inertial attitude...

Experimental and system study of Reaction Wheels. Part I: Measurement and statistical analysis of force and torque irregularities

Torque and force irregularities of running reaction wheels were studied. In this first part of the study report results from noise measurements at constant wheel speeds on various types of current technology European reaction wheels, both with ball- and magnet bearings and with DC or AC drive motor, are presented. The measured noise in radial...

Experimental and system study of Reaction Wheels. Part II: System study on wheel state feedback

The increasing power of on-board processors allows more freedom in the design and operation of reaction wheel control systems. This report discusses several performance and implementation aspects of the operation of wheel systems which have their own internal feedback control system. A model following control concept is found to be superior. The...

Hybrid equations for translational and rotational motion of flexible spacecraft

The report deals with the equations of motion of spacecraft with rigid main body, flexible appendages, and rotors and jets on the main body. The hybrid coordinate modelling method is applied. The resulting equations describe the translational motion of the spacecraft, the rotational motion, and the coupling between these two types of motion. The...

Study of an attitude acquisition measurement technique using the ESA starmapper: Part I: Executive summary

The study deals with the rotational motion of a spin-stabilized spacecraft equipped with a V-slit sun sensor and the X-slit ESA starmapper. Assuming complete absence of an a priori attitude estimate, it is required to produce a rough estimate of the spacecraft attitude motion. It was assumed that sensor misalignments, external torques and...

Study of an attitude acquisition measurement technique using the ESA starmapper: Part two: final report

The study deals with the rotational motion of a spin-stabilized spacecraft equipped with a V-slit sun sensor and the X-slit ESA starmapper. Assuming complete absence of an a priori attitude estimate, it is required to produce a rough estimate of the spacecraft attitude motion. It was assumed that sensor misalignments, external torques and...

Digital filtering methods, with applications to spacecraft attitude determination in the presence of modelling errors. Part II: Extension of theory, and applications

The present issue is the second and final part of a report describing the results of a study about digital filtering. The first part is available as the report NLR TR 760U8 U. The report considers a number of digital filtering methods and gives examples of their application. The methods include batch processing methods and recursive methods....

Accuracy of attitude control systems for satellites using double gimballed momentum wheels