ON-ORBIT EXPERIENCE OF THE FIRST GALILEO SATELLITE, GIOVE-A

摘要

In July 2003 the European Space Agency (ESA) placed a 28 million Euro contract with Surrey Satellite Technology Ltd (SSTL) for the delivery, in 2005, of a Galileo demonstrator satellite named GIOVE-A. GIOVE-A was designed, built and launched in less than 30 months. The satellite carries both ESA-furnished and SSTL-developed payload elements, giving an advanced and flexible capability suited for the mission's primary aim of frequency filing and also for technology demonstration, environmental monitoring and signal experimentation. GIOVE-A was launched on the 28th December 2005 into Galileo's Medium Earth Orbit (MEO) at an altitude of 23,222 km by a Russian Soyuz launcher with a Fregat upper stage. Platform commissioning took a little over a week and on the 12th January 2006, the first Galileo navigation signals were broadcast from GIOVE-A to Earth. The signals were monitored using Rutherford Appleton Laboratory's (RAL's) 25 metre dish at Chilbolton, Hampshire, UK and also tracked by a Galileo receiver installed at SSTL's control centre in Guildford, Surrey, UK. Thus, the first step towards the securing of Galileo's frequencies for Europe was taken. A range of signals and transmission combinations continued to be broadcast by GIOVE-A to complete the formal ITU filing process. The mission also heralds SSTL's debut "beyond LEO" with the first flight of SSTL's GMP platform targeted at the MEO, GEO and interplanetary orbits. The GIOVE-A mission demonstrates that SSTL's rapid-response and low-cost small satellite philosophy can be translated into larger, higher profile programmes such as Galileo. The paper discusses the design and construction of the satellite and its ground segment. Following launch we give an overview of the activities performed to generate the Galileo signal-in-space and an overview of the use of the satellite to de-risk the ongoing Galileo programme.