This course on “Global Navigation Satellite Systems and the new European Galileo System” has been written by the Polytechnic University of Madrid (UPM), a partner in the consortium in charge of managing the Galileo Information Center (GIC) for Mexico, Central America and the Caribbean, and has been presented by three doctors from the National Autonomous University of Mexico (UNAM), Dr. José Alberto Ramírez, Dr. Rafael Chávez Moreno and Dr. Jorge A. Ferrer Pérez, with the collaboration of Dr. Miguel A. Salas Natera from the Polytechnic University of Madrid (UPM) and the coordinator of the Galileo Information Center, Ing. Elena Megias.
Module 1
Introduction to GNSS
This chapter is the first on global navigation satellite systems (GNSS). The chapter starts with a brief history of navigation and then describes what a GNSS is and gives examples of GNSS (Galileo, GPS and Glonass).
Module 2
Galileo Basics
This chapter introduces the basics of Galileo, the European GNSS: what is Galileo, Galileo services (OS, SAR, PRS, HAS and OS-NMA), Galileo key points and differentiators.
Module 3
GNSS positioning
All the key concepts of positioning are presented using measured ranges between a receiver and the satellites. The concept of trilateration is described and then the basic observation equations are described.
Module 4
Main sources of error
GNSS measurements are affected by various sources of error. If the influence of the error sources is large, it means that the uncertainty of the GNSS receiver position increases and the accuracy may be degraded. These errors are described here.
Module 5
GNSS performance
GNSS performance is evaluated using four criteria: accuracy, the system must provide accurate positioning; integrity, satellites must transmit reliable and not erroneous information; availability, the system must guarantee its normal operation during a high % of time and continuity, capacity of the system to work without interruption.
Module 6
Structure of radio signals
Global Navigation Satellite System (GNSS) refers to a constellation of satellites that provide signals from space that transmit positioning and timing data to GNSS receivers. The structure of these signals is described in this chapter.
Module 7
Orbits and ephemeris
To calculate the position of a point on the earth's surface, it is necessary to know the coordinates of the satellites that are being observed. These coordinates are given in GNSS ephemeris and can be obtained from various sources. This chapter introduces the concept of orbit and ephemeris.
Module 8
Galileo system
This chapter introduces all of Galileo's key concepts. The chapter begins by presenting some Galileo applications and then describes the Galileo architecture (space, ground, and user segment). Then the Galileo signal in space is described along with the Galileo navigation messages.