Simulations without data updates using analytical attitude propagator GSAM for spin stabilized satellites

M C Zanardi,G Borderes-Motta,V Mota

doi:10.1088/1742-6596/1365/1/012020

Abstract

The objective of this work is to validate the GSAM propagator using new data provided by the National Institute for Space Research (INPE) from SCD1 and SCD2 data collection satellites, with emphasis on long interval simulations without daily data updates. Originally, only 40 days of data were available to test the program, constraining any attempts to measure its precision more accurately. Recently, over two decades of data regarding both satellites’ orbital and attitude parameters were provided, allowing further studies and validation of the program. The rotational motion equations are composed by the gravity gradient torque, aerodynamic torque, solar radiation pressure torque, residual and eddy current magnetic torques, the latter using a dipole geomagnetic model. The results are considered fitting when the mean deviation between the calculated variables and the real satellite data stay within 0.5° for the right ascension and declination angles and 0.5 rpm for the spin velocity. Intervals that meet the required precision were found for all years, from three to up to 15 days of simulation without data update. The consistent detection of such intervals further corroborate the use of the propagator to estimate the orientation of the satellites studied in their missions.

Highlights

It is unarguable that satellites are vital to tackle several tasks of modern life, influencing society from weather forecasting to intelligence and defense
The main causes of perturbation for these objects [1] are the gravity gradient torque (GGT), derived from the Earth’s gravity force attracting the satellite’s non-uniformly distributed mass; the solar radiation torque (SRT), consequence of the variation of momentum of incident photons hitting the surface of the satellite; the aerodynamic torque (AT), caused by collision between molecules from the high atmosphere with the satellite’s surface; the residual magnetic torque (RMT), result of the interaction between the magnetic moment over the rotation axis of the satellite and the geomagnetic field; and, lastly, the eddy
The following tables compile the mean deviations for the three variables studied – the right ascension angle, the declination angle and the spin velocity

Summary

Introduction

It is unarguable that satellites are vital to tackle several tasks of modern life, influencing society from weather forecasting to intelligence and defense. This work is focused on satellites with low eccentricity orbits and spin stabilization, characterized by rotation around the axis of greatest principal moment of inertia. Satellites are subject to multiple external forces, affecting their rotational motion by inducing different torques. The main causes of perturbation for these objects [1] are the gravity gradient torque (GGT), derived from the Earth’s gravity force attracting the satellite’s non-uniformly distributed mass; the solar radiation torque (SRT), consequence of the variation of momentum of incident photons hitting the surface of the satellite; the aerodynamic torque (AT), caused by collision between molecules from the high atmosphere with the satellite’s surface; the residual magnetic torque (RMT), result of the interaction between the magnetic moment over the rotation axis of the satellite and the geomagnetic field; and, lastly, the eddy.

Objectives

Methods

Results

Conclusion