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Keysight Technologies
GNSS Technologies and
Receiver Testing




Application Note
02 | Keysight | GNSS Technologies and Receiver Testing - Application Note



Contents

GNSS overview...................................................................................................................3
GNSS technology applications and growth drivers...............................................4
GNSS system description ..........................................................................................4

GPS .......................................................................................................................................6
The GPS transmitted signal .......................................................................................6
The GPS navigation message ...................................................................................7
Assisted GPS ......................................................................................................................8

GLONASS ............................................................................................................................8
The GLONASS transmitted signal ............................................................................9
GLONASS signal components .......................................................................... 10
The GLONASS navigation message ...................................................................... 11
The Galileo E1 Open Service transmitted signal ................................................ 12
Galileo signal components................................................................................ 13
The Galileo navigation message............................................................................ 14

Beidou ............................................................................................................................... 15
The Beidou transmitted signal ............................................................................... 15
Beidou signal components ............................................................................... 15
The Beidou navigation messages ......................................................................... 17

GNSS Receiver Testing .................................................................................................. 19
Typical GNSS receiver tests ................................................................................... 19
Requirements for GNSS receiver testing ............................................................. 20
GNSS test signals for R&D and design verification ..................................... 20
GNSS test signals for manufacturing ............................................................. 22

GNSS Receiver Testing Using N7609B Signal Studio for GNSS ............................ 23
GNSS receiver test setup........................................................................................ 23
Generating real-time GNSS signals ...................................................................... 24
Real-time control of satellite signals .............................................................. 27
Create custom scenarios for any time, date, and location ............................... 28
Editing scenario files to provide repeatable impairments................................. 32
Trajectory generator utility ..................................................................................... 34
Apply an antenna model ......................................................................................... 35

Conclusion........................................................................................................................ 36

Web Resources ............................................................................................................... 36

Related Literature ........................................................................................................... 37

References ....................................................................................................................... 37
GNSS Tutorials and Links ....................................................................................... 37
03 | Keysight | GNSS Technologies and Receiver Testing - Application Note



GNSS Overview

Global Navigation Satellite Systems (GNSS) is the general term used for
systems that allow users to determine their location based on information from
satellites. In addition to the Global Positioning System (GPS) which is run by
the United States, the GLONASS system from Russia is now in full operation.
The Beidou system from China, also known as Compass, and the Galileo system
from the European Union are also in the process of being deployed.

Of the 4 main systems in various stages of deployment today, GPS is the oldest,
and has been in operation providing worldwide coverage since 1994. The
system continues to be upgraded, with Block IIF satellites launched in 2012 and
launches of Block III satellites planned in order to provide additional signals and
services. The GLONASS system was first launched by the Soviet Union in 1982,
but fell into disrepair after the collapse of the Soviet Union. Russia has restored
and completed the system which became fully operational in October 2011 and
provides worldwide coverage today. Russia is continuing to enhance the system
with the launch of new GLONASS-K satellites which will provide new signals
similar in nature to GPS and Galileo.

The other two systems, Galileo and Beidou, are still being deployed. Galileo
has been under development by the European Community and European Space
Agency for many years. Two experimental satellites were launched in 2005 and
2008. In 2011 and 2012, the first 4 in-orbit validation satellites that will be part of
the operational system were launched. Initial limited service is planned to begin
by 2015, with the completion of the full system planned for 2020.

With the launches that took place in September 2012, the Beidou system which
began limited operation in December 2011 has been expanded to include 15
satellites, enabling regional service covering Asia Pacific. Completion of the full
system is planned for 2020. Development of products supporting Beidou has
been somewhat limited because the complete Interface Control Document (ICD)
was not released by the Chinese government until December 2012. Now that
the ICD is available, development of Beidou products is expected to increase
rapidly.

In addition to these 4 satellite systems that allow receivers to determine their
location, there are other related satellite systems. Satellite-based augmentation
systems (SBAS) are geostationary satellites that provide data to improve the
positioning accuracy of GNSS receivers in a region. These include the Wide
Area Augmentation System (WAAS) for North America, European Geostationary
Navigation Overlay Service (EGNOS) for Europe, the Japanese Multi-functional
Satellite Augmentation System (MSAS), and the Indian GPS Aided Geo
Augmented Navigation (GAGAN) system. Regional navigation satellite systems
such as Japan's Quazi-Zenith Satellite System (QZSS) include satellites that
orbit over a specific region, providing improved coverage over limited areas.
The first QZSS satellite is in operation and there are devices that support QZSS
today. The Indian Regional Navigation Satellite System (IRNSS) is also under
development, with 3 geostationary and 4 geosynchronous satellites planned.
04 | Keysight | GNSS Technologies and Receiver Testing - Application Note




GNSS technology applications and growth drivers
Growth in the GNSS market is being driven by several factors, the primary one
being the burgeoning demand for location-based services and applications in
smart phones and tablets. Other factors include more vehicles being sold with
in-car navigation systems and the addition of GPS in consumer devices such as
digital cameras and sports watches. Tracking applications are also becoming
more common. For example, companies are tracking the vehicles in their
fleets to get real-time logistical information, and personal tracking applications
monitor workers or the elderly for safety. Additionally, police use this technology
to track criminals who are under house arrest or are on parole. Pet tracking
devices and services are now available as well.

To support the growth of these applications, WLAN and cellular chipset
companies are actively engaged in the development of GNSS chipsets and
modules. Additionally, growing demand for devices that support multiple
GNSS has prompted the development of multi-GNSS chipsets including GPS +
GLONASS and GPS + Galileo or Beidou.

There are also applications for GNSS in the high-precision commercial market
such as surveying and aviation, as well as aerospace/defense applications such
as guidance systems for unmanned aerial vehicles or missiles. This application
note will focus on consumer devices and applications.


GNSS system description
There are 3 major segments of a GNSS system.