Introduction

On 8 april 2010 the European Space Agency launched Cryosat-2 which is expected to fly for nominally 3 years. As shown in the image, the satellite is equipped with a newly designed microwave radar to observe ice topography on Earth with unprecedented resolution and accuracy. Crucial for the proper operation of the Cryosat-2 mission is accurate knowledge of the trajectory of the satellite.

Background

Presently the section of astrodynamics and space missions is involved in an ESA sponsored project focusing on orbit determination of Cryosat-2 whereby use is made of tracking data acquired by ground-based laser tracking stations and the Doppler navigation system DORIS. Demonstrated during the ongoing commissioning phase of the Cryosat-2 mission is a 3D reconstruction of the position of the spacecraft to within 10 cm rms.  The orbit error projected along the altimeter range is known probably better than 2 cm rms.  Although such errors may look small, this uncertainty could be significant when the altimeter data is used to reconstruct maps of ice loss on Earth. ESA therefore suggested to investigate independent means to validate and possibly enhance precision orbit determination procedures. This activity is relevant for understanding the consequences of climate change.

Task

For the validation of the computed Cryosat-2 orbits the project should focus on an independent validation and possibly an improvement of the calculated satellite orbits. One possibility is to compare sea level profiles measured with the SIRAL altimeter over ocean surfaces and to compare the sea level change at crossing points.  Another possibility is to evaluate sea levels observed by Cryosat-2 to other ocean altimeters and also tide gauge stations.  The purpose of the MSc topic project is to investigate such opportunities and to demonstrate with independent means the quality of the Cryosat-2 mission data. All suggestions to demonstrate the quality of existing precision orbit determination procedures are also welcomed.

Supervisor

E. Schrama, room 9.13, Faculty of Aerospace Engineering, TU Delft, e.j.o.schrama@tudelft.nl