Projects:

Definition & Development
of Galileo

Signal Structure

Galileo Test Bed GATE

ESA Galileo Test Bed GSTB_V1

GNSS Software
Simulation

C-Nav Study

At the Institute of Geodesy and Navigation important aspects of the Galileo signal structure have been investigated and many improvements have been suggested. An overview on the signal structure (status Sept. 2002) is listed below. Detailed investigations on topics examined at the Institute of Geodesy and Navigation can be found in the research database.

Galileo will provide 10 navigation signals in Right Hand Circular Polarization (RHCP) in the frequency ranges 1164-1215 MHz (E5a and E5b), 1215-1300 MHz (E6) and 1559-1592 MHz (E2-L1-E1), which are part of the Radio Navigation Satellite Service (RNSS) allocation. An overview is shown below, indicating the type of modulation, the chip rate and the data rate for each signal. The carrier frequencies, as well as the frequency bands that are common to GPS or to GLONASS are also highlighted.

All the Galileo satellites will share the same nominal frequency, making use of Code Division Multiple Access (CDMA) compatible with the GPS approach.

Six signals, including three data-less channels, so-called pilot tones (ranging codes not modulated by data), are accessible to all Galileo Users on the E5a, E5b and L1 carrier frequencies for Open Services (OS) and Safety-of-life Services (SoL). Two signals on E6 with encrypted ranging codes, including one data-less channel are accessible only to some dedicated users that gain access through a given Commercial Service (CS) provider. Finally, two signals (one in E6 band and one in E2-L1-E1 band) with encrypted ranging codes and data are accessible to authorized users of the Public Regulated Service (PRS).

A ½ rate Viterbi convolutional coding scheme is used for all the transmitted signals.

Four different types of data are carried by the different Galileo signals:

• OS data, which are transmitted on the E5a, E5b and E2-L1-E1 carrier frequencies. OS data are accessible to all users and include mainly navigation data and SAR data.

• CS data  transmitted on the E5b, E6 and E2-L1-E1 carriers. All CS data are encrypted and are provided by some service providers that interface with the Galileo Control Centre. Access to those commercial data is provided directly to the users by the service providers.

• SoL data that include mainly integrity and Signal in Space Accuracy (SISA) data. Access to the integrity data may be controlled.

• PRS data, transmitted on E6 and L1 carrier frequencies.

For more details refer to:

 Galileo Frequency and Signal Design (Article in GPS World)

Point of contact: Thomas Pany