International Global Navigation Satellite Systems Association
IGNSS Conference 2016
Colombo Theatres, Kensington Campus, UNSW Australia
6 – 8 December 2016
Multi-GNSS for Space Service Volume
Arunkumar Rathinam
Australian Centre for Space Engineering Research, UNSW Australia
a.rathinam@student.unsw.edu.au
Andrew G. Dempster
Australian Centre for Space Engineering Research, UNSW Australia
a.dempster@unsw.edu.au
ABSTRACT
Global Navigation Satellite System (GNSS) play a crucial role in enabling
the autonomous navigation capabilities for space vehicles. GNSS offers
good coverage in terrestrial as well as in Low Earth Orbit (LEO) and in turn
enables autonomous space vehicle operations. The extension of this service
to Space Service Volume (SSV) is made feasible through tracking the
signals available over the limb of the earth. But with a single constellation
configuration, the receiver can experience significant outages at higher
altitudes. This paper explores the possibility of multi-GNSS configurations
to enable consistent positioning at higher altitudes. For this study, navigation
systems considered include GPS, GLONASS, GALILEO, BEIDOU, QZSS,
and SBAS. This paper also characterises the GNSS availability based on
three main parameters: antenna pattern (transmitting and receiving
antennas), synodic period (between user and GNSS), and user orbital
parameters. The study is extended through MATLAB simulation to a wide
array of altitude and inclination combinations in the SSV which is helpful in
mapping the user orbit against GNSS service availability. It is evident from
the simulation results that a multi-GNSS approach has a collective advantage
in high orbits and thus future missions can effectively utilize the services
available in the SSV to lower the overall cost of the mission.
KEYWORDS: Space Service Volume, Multi-GNSS
1. INTRODUCTION
During the last two decades, GNSS has evolved into a robust system addressing extensive
user requirements and offering high precision Position, Navigation, and Timing (PNT)
services. GPS and GLONASS are the two fully operational global navigation systems, where
others such as GALILEO and BEIDOU are under development. Regional support system
such as QZSS (Quasi-Zenith Satellite System) is also expanding and the constellation was
designed to augment GPS signals over the Japanese region to enable increased satellite
visibility in urban canyons. Other stand-alone regional navigation system include
IRNSS/NAVIC has seven satellites deployed in orbit and is ready for operation. Apart from
