About GNSS
Satellite Navigation
17
User Manual 1178.6379.02 ─ 01
data provided by the base station already serves speeding up the acquisition proc-
ess, the UE only has to track the code and carrier phase.
4.2 SBAS Overview
Brief introduction to the satellite-based augmentation systems (SBAS)
The satellite-based augmentation system uses geostationary satellites (GEO) to broad-
cast GNSS coarse integrity and wide area correction data (error estimations), and
ranging signal to augment the GNSS.
The SBAS broadcasts augmentation data in the GPS frequency band L1 (carrier fre-
quency of 1575.42 MHz), uses the BPSK modulation, and the C/A PRN code of GPS.
The SBAS provides data for a maximum of 51 satellites. In the SBAS, the term pseudo
random number (PRN) is used instead of the term space vehicle (SV). There are 90
PRN numbers reserved for SBAS, where the numbering starts at 120.
Several SBAS systems are still in their development phase, like, for example, the
SDCM in Russia Federation, and GAGAN in India.
SBAS systems that are currently in operation argument the US GPS satellite naviga-
tion system, so that they are suitable, for example, for civil aviation navigation safety
needs. The following SBAS systems are supported by R&S
SMW:
●
EGNOS
EGNOS (European geostationary navigation overlay service) EGNOS is the Euro-
pean SBAS system
●
WAAS
WAAS (wide area augmentation system) is the SBAS system in United States
●
MSAS
MSAS (multi-functional satellite augmentation system ) is the SBAS system work-
ing in Japan. It uses the multi-functional transport satellites (MTSAT) and supports
differential GPS.
●
GAGAN
GAGAN (GPS aided geo augmented navigation system) is the SBAS implementa-
tion by the Indian government.
4.3 GNSS Components Overview
The GNSS system comprises of three main components: the space segment, the
ground segment and the user segment.
GNSS Components Overview
