Free eBook: These are exciting times for GNSS chipset designers, with lots to gain for those who are first to market with high-quality, innovative products.
Testing is a critical part of the development process, whether you’re working in a commercial R&D team or an academic research lab. But without the right tools and practices, testing can also hold up the process for weeks or months, tying up time and resources and delaying market entry.
Download our free eBook to discover:
- Our ten key factors to consider when conducting GNSS receiver performance tests
- How Spirent’s systems can help you enhance testing and reduce time to market
Simply enter a few details opposite to receive your free eBook—and happy reading!
About Spirent
Spirent has been the global leader in GNSS testing near 30 years. Spirent delivers navigation and positioning test equipment and services to governmental agencies, major manufacturers, integrators, test facilities and space agencies worldwide.
Ten Factors to Consider when Testing
New GNSS Chipset Designs
A Spirent eBook
Introduction
Satellite navigation and positioning technologies have been with us
for many years, but so far they’ve only scratched the surface of what’s
possible. Now, several developments are contributing to an explosion
in innovation in consumer, civilian and military markets, opening up
huge opportunities for designers of GNSS chipsets.
The introduction of new satellite constellations and the increasing
sophistication of alternative positioning technologies are driving
advances in GNSS receivers, software applications and device
form factors. The result is a booming market for location-based
services, ranging from basic photo geotagging to ultra-high-precision
positioning for automotive, aerospace and military use.
Page 2SPIRENT eBook
These are exciting times for GNSS chipset designers, with lots to
gain for those who are nullst to market with high-nullality, innovative
products. Testing is a critical part of the development process,
whether you’re working in a commercial nullnullteam or an academic
research lab. nullut testing can also hold up the process for weeks or
months, tying up time and resources and delaying market entry.
This ebook is about how to make the testing process as fast, efnullient
and cost-effective as possible, without sacrinulling any of the rigour
that goes into developing an outstanding new product. nullt covers null
factors that a GNSS chipset design team should consider when setting
out to test a prototype, and considers ways in which those factors
can be addressed simply and affordably.
SPIRENT eBook
Ten Key Considerations
nullrawing on our null years as the market leader in GNSS testing, we’ve
identinulld null key factors to consider when testing the performance of
a new chipset design or prototype at the nullnullstagenull
1. Live snull testing vs simnullationnull best practice in testing approaches
2. nullasic performance testsnull the nine key tests of receiver performance
null nullppnullcationnullpecinull performancenull ensuring the chipset functions in
the intended application
null nullnulltinullNSS snullportnull future-proonullg designs as new constellations
come onstream
Page nullSPIRENT eBook
null nullnullrid positioningnull how to test for nullaccuracy everywherenull
null nullnterferencenull understanding how different kinds of interference may
affect receiver performance
null nulleanullwornull verinullationnull techninulles to increase the speed and
efnulliency of nullld testing
null Preparing for certinullationnull using testing to accelerate the
submission process
null nullncreasing sanulls to nullnullnull using test data to demonstrate nullality
and accelerate the sales process
1null Choosing the right enullipmentnull making sure you have the kit you need
Page nullSPIRENT eBook
1. Live Snull vs Simnullation
Since the early days of GNSS, there have been two alternatives
available to those wishing to test a navigation systemnullnullld test and
laboratory simulation.
nullile Gnull was the only GNSS available for the manullrity of
applications, live sky testing was a viable nullf expensive and nullwednull
option. Today, the switch from simple Gnull navigation to the use of
multiple satellite systems means live sky testing for new designs is no
longer an option.
nullirstly, designers now need to test receiver performance with
GNSS systems that are either only partially live nulluch as
Galileonull or not yet live at all nulluch as nullmpassnull
Page nullSPIRENT eBook
Secondly, the emergence of multiple additional positioning
technologies, such as nulli-nulli, cellular, satellite augmentation systems
and sensor-based systems, means designers need to test chipsets in
environments that present a mixture of signals, which is extremely
difnullult to do in the real world.
Thirdly, designers of today’s high-precision receivers need to
understand how the chipset performs in a wide variety of conditions,
including extremes of temperature and pressure, and how it handles
multiple types of interference, some of which may be extremely rare
nullut still critical to testnull
Page nullSPIRENT eBook
nullor these reasons, best practice indicates that the manullrity of tests are
done under controlled, repeatable conditions in a secure laboratory
using one or more null simulator units. This not only provides the
accuracy that designers need, but also simplinulls testing in four
key waysnull
1. nulltnulls fasternull much of the testing with null simulation can be
automated, meaning tests can run constantly, including overnight,
with no human intervention. nullt’s also much nullicker to get going in the
lab than it is to transport vehicles, staff and enullipment to and from
nullld test locations.
2. nulltnulls cheapernull null simulation removes the logistical cost of nullld
testing, and its high level of automation means it renullires fewer man-
hours and can be completed with smaller testing teams.
Page nullSPIRENT eBook
null nulltnulls more accnullatenull in contrast to the live sky environment, which
is constantly changing, simulated scenarios can be repeated again
and again. This enables accurate comparative testing null.g. of different
chipsets during the vendor selection processnulland removes any
uncertainty around whether changes in performance are due to the
signal environment or the product design.
null nulltnulls more nullxinullenull lab simulation lets you generate any combination
of signals and conditions that you need to test. nullou can model
constellations and signals that do not yet exist in the real world.
nullou can also easily test hybrid positioning capabilities by modelling
combinations of satellite, nulli-nulli and sensor signals.
nullor more about the benenulls of null simulation, read our enulloknull
The risks and limitations of GNSS live sky testing
Page nullSPIRENT eBook
2. nullasic Performance Tests
No matter what the intended end-user application, every new receiver
needs to be able to conduct a number of basic tasks effectively, from
nullickly acnulliring an initial null to coping adenullately with common
types of interference such as multipath effects and signal obscuration.
nulln testing the underlying functionality of any GNSS receiver design
in the laboratory, it is essential that the enullipment is subnullcted to a
known and repeatable stimulus so that the correct response can be
assessed and the performance can be adnullsted accordingly.
nullile a receiver’s desired capabilities will vary depending on its
intended use, Spirent recommends nine basic tests to assess and
verify the performance of any GNSS receiver
design or design iteration.
Page 1nullSPIRENT eBook
1. Conullnulltart time to nullst nullnull starting a receiver from scratch null
the nullst experience a user will have
2. nullarmnulltart time to nullst nullnull as above, but with the time and
almanac in the receiver’s memory
null nullotnulltart time to nullst nullnull re-starting the receiver with time,
almanac and ephemeris data, within nullnullm of the last null
null nullcnullisition sensitivitnull the minimum received power level at which
the receiver can obtain a null
null Tracnullng sensitivitnull the minimum power level at which the
receiver can maintain lock
null nulleacnullisition timenull time taken to reacnullire the signal after passing
through an obstacle
Page 11SPIRENT eBook
null Static navigation accnullacnull taking into account the many internal
and external variables that can affect receiver performance
null Dnullamic navigation accnullacnull accuracy while the receiver is in
motion on one, two or three axes
null nulldio frenullencnullinterferencenull susceptibility to incidental or
intentional nullnullmming’nullradio interference
nullnducting these nine basic tests as standard, using an null simulator
to guarantee that the test scenario and parameters are identical each
time, removes signinullant amounts of time, effort and uncertainty from
the testing process.
nullor more information, read our ebooknull
Simulation versus real world testing
Page 12SPIRENT eBook
null nullppnullcationnullpecinull performance
nulln addition to the nine standard tests mentioned above, designers
will also want to conduct a raft of more specinull tests relating to the
intended end-application of the receiver. These might be automotive-
specinull, avionics-specinull nullhich might involve, for example, the
receiver and its antenna being at any range of angles depending on
vehicle manoeuvresnullor space-specinull.
The key to any advanced nullnulltesting is the ability to simulate a
specinull scenario with absolute repeatability so that adnullstments can
be made and the test can be re-applied. These scenarios can be of
almost any nature, and while each one may be unlikely to
occur in real life, a reliable GNSS receiver will
be expected to perform reliably under all
possible conditions.
Page 1nullSPIRENT eBook
nulln each case, using a GNSS simulator will accelerate and simplify the
testing process either by providing suitable ready-written tests, or
by storing custom-coded scenarios that can then be replayed with
absolute repeatability, time and time again.
nullor more information, read our ebooknull Testing GNSS-nullnabled devices
for industrynullnullip selection
Page 1nullSPIRENT eBook
null nullnulltinullNSS Snullportnull
The vast manullrity of new chipsets being developed today are capable
of receiving and processing signals from more than one satellite
system, and multi-GNSS support is now a key consideration in almost
every GNSS chipset nullnulllab.
null new constellations go live, there are many opportunities to
enhance coverage and positioning accuracy, and open up new
geographical markets, by including support for new GNSS such as
GnullnullnullS, Galileo and smaller regional and augmentation systems in
addition to Gnull.
Page 1nullSPIRENT eBook
nullesigners with an eye to future-proonullg receivers will also want to
include automatic upgrades for forthcoming constellations such as
nullmpass nullnulleidounulland planned additions to Galileo. That means
ensuring the receiver performs as intended with signals that are not
yet available in the live sky.
The problem is that while these systems are functionally similar,
there are manullr differences in the way they go about their respective
tasks. nullifferent constellations broadcast on different frenullencies, have
different timebases, and take different approaches to modulation and
ionospheric modelling.
null a result, the range of tests renullired in the nullnulllaboratory
is considerably wider than those traditionally used in
the development of nullvanillanullGnull receivers.
Page 1nullSPIRENT eBook
null nullulti-GNSS simulator provides an effective and efnullient means
to test GNSS receivers and the systems that rely on them. nullith a
nullulti-GNSS simulator, every time a test scenario is run, the signals
produced are identical, so you can guarantee that the receiver is
being stimulated with exactly the same signals every time the test
is run.
null multichannel nullulti-GNSS simulator will allow all the necessary tests
to be run using signals from single and multiple GNSSs. nulld the
ability to nullmix and matchnullsignals from different systems will allow
designers to create receivers that can perform reliably anywhere
in the world.
Page 1nullSPIRENT eBook
null suitable simulator will also be capable of upgrading to simulate
other GNSS signals as soon as they have been denulled by the
system operator.
nullor more on using nullulti-GNSS simulators to increase testing efnulliency
and accuracy, download our enullok nullulti-GNSS for technology
developers.
Page 1nullSPIRENT eBook
null nullnullrid Positioning
null demand for continuous positioning and indoor location accuracy
increases across a broad spectrum of industries, nullnull and integrators
are looking for solutions that can also process signals from alternative
sources to GNSS.
There is a rapidly growing market for hybrid receivers that can
combine positioning information from sources such as nullsisted-Gnull,
nullsisted-GnullnullnullS, mobilenullellular networks, nulli-nulli access points
and inbuilt motion sensors. These signals can be used to maintain
positioning data in areas where GNSS signals are weak or unavailable,
such as inside buildings and malls and in urban canyons.
Page 1nullSPIRENT eBook
The hybrid positioning market is predicted to be hugenullnullnullnullesearch
estimated in nullnull that hybrid receivers will represent nullnullof all
positioning solutions by nullnull. nullowever, the challenge for chipset
designers is creating the best combination of inputs to deliver the
kind of positioning accuracy renullired by the end-application.
Getting an effective product to market will renullire careful
development and a test environment that provides total control over
multiple, coherent sources to facilitate iterative improvement.
The ability to apply rigorous, iterative performance testing to new
hybrid receivers and boards will be critical to success in this
booming market.
nullor more about testing hybrid positioning technologies, download our
companion enulloknullnullybrid nullositioning.
Page 2nullSPIRENT eBook
null nullnterference
GNSS signal interference may take many forms, some common and
some extremely rare. null good nullnullteam will want to understand
how the receiver copes with all kinds of interference, from simple
multipath effects to intentional and unintentional signal nullmming,
interference from services operating in nearby frenullencies, and
ionospheric effects such as solar nullres.
The key to successful testing for interference is the ability to simulate
a specinull scenario with absolute repeatability so that adnullstments
can be made and the test can be re-applied. These scenarios can be
of almost any nature, and while some conditions may be unlikely to
occur in real life, a reliable nullulti-GNSS receiver will be expected to
perform reliably in all possible circumstances.
Page 21SPIRENT eBook
null null simulator with a fully-featured software platform can model
all kinds of interference including multipath, obscuration, signal
nullmming and ionospheric effects. To save time writing custom code
for different scenarios, and to increase the efnulliency of the testing
process, look for software that has a broad range of test cases
already built.
nullor more information, read our ebooknull Testing GNSS System nullrrors.
Page 22SPIRENT eBook
null nulleanullnullornull nullerinullationnull
nullile the bulk of testing can now be done more easily, more
accurately and more cost-effectively in the lab, you will still want to
do some live sky testing to verify the performance of the receiver in
the real world.
nullve sky testing can be made much faster and simpler by recording
the real-world signals on an initial nullld trip, and then replaying them
in the lab. nullecord and playback systems reduce testing, trials
and travel costs substantially recording real-life Gnull,
GnullnullnullS or nullSS signals nullncluding real world
fades, multipath and interferencenullon to the
internal hard drive of the unit.
Page 2nullSPIRENT eBook
These signals can then be replayed limitless times in the lab, giving
you the repeatability you need to accurately compare the performance
of different designs or design iterations.
For more about cost-effective live sky testing in the lab, read our
eBook An introduction to GNSS null nullecord nullnulllayback Systems nulltnull
Page 24SPIRENT eBook
null Preparing for certinullation
nullefore a new GNSS or hybrid chipset design can be commercialised,
it may need to be certinulld by a relevant authority as being of a
sufnullient standard for the intended end-application.
nullepending on the intended use, standards and certinullation
authorities can range from the nullnull consortium for mobile devices, to
the nullnternational nullaritime nullrganinulltion for maritime navigational aids
and nullspas-Sarsat renullirements for GNSS-enabled distress beacons.
Page 2nullSPIRENT eBook
The certinullation process can be a lengthy one, especially if the design
is renullcted by the standards authority and renullires further work in the
lab. nullonths or even years can be lost in the process, during which
commercial opportunities and competitive advantages can be lost.
nullgorous testing can help to speed up the certinullation process,
especially where the same test enullipment, test cases and scenarios
used by the certinullation authority can also be used for testing in the
lab prior to submission. Subnullcting the design to the same tests, and
producing meaningful reports demonstrating that the receiver passes
those tests, can lead to faster certinullation and greatly increase the
likelihood of passing certinullation nullst time.
nullor more information on nullipset nullrtinullation, please download our
Nnullnullnullpplication Notenull Testing GNSS-nullnabled devices for industry
certinullation with Testnullrive-GNSS.
Page 2nullSPIRENT eBook
null nullow can nullincrease sanulls to nullnullnull
nullnull are under pressure to bring new products to market faster than
ever, so anything that receiver designers can do to speed up the
chipset vendor selection process will be welcome.
nullroviding evidence of rigorous testing for all capabilities and
conditions, together with meaningful, readily-understood reports
documenting the results of the tests, can help nullnulland integrator
partners to understand the receiver’s performance nullality faster.
Page 2nullSPIRENT eBook
Similarly, sharing details of the test cases, scenarios and testing
enullipment used in the lab can provide valuable guidance to the nullnull
in setting up their own tests and test environment.
nullinally, in applications where there is currently no industry standard
or certinullation authority for receiver nullality, nullnullorganisations that
specify and publish a standard set of tests will be better able to
demonstrate product nullality to prospective nullnullpartners and
their customers.
nullor more information, read our ebooknull
nullundamental GNSS nulleceiver
nullaracterisation.
Page 2nullSPIRENT eBook
1null nullatnulls the nullst enullipment for mnullneedsnull
nulloosing the right enullipment nullwithout over-investing in software and
hardware that you don’t need nullis the key to efnullient, accurate and
cost-effective testing in the lab.
Spirent offers a wide range of enullipment that’s used in nullnull
laboratories across the world to accelerate and streamline the testing
process. Some of our key products for chipset nullnullteams includenull
nullardware
Spirent GSSnullnull nullnulltinullNSS Simnullatornull null comprehensive, highly
adaptable tool, designed to meet the simulation renullirements of
the world’s most demanding and pioneering nullnullteams. nullt provides
GnullnullnullS, GnullnullnullS and Galileo signals in a single unit. Gnull
connullurations can also support nullSS and SnullS. nullassinulld signals
and various options are also available.
Page 2nullSPIRENT eBook
Spirent GSSnullnull nullnulltinullNSS Simnullatornull null powerful, nullxible platform
for nullulti-GNSS development, integration and verinullation testing.
nullulti-GNSS Simulation System offers multiple channels of GnullnullnullS,
GnullnullnullS andnullr Galileo null signals.
Spirent GSSnullnull nullecord and PnullnullacnullSnulltemnull a complete,
standalone system for capturing live GNSS null data in the nullld and
replaying it with optimal nullelity and performance back in the lab.
Spirent GSSnullnull nullinulli Simnullatornull a practical, intuitive instrument
for testing nulli-nulli positioning technology in the lab nulleither as
a standalone solution, or in tandem with Spirent’s nullulti-GNSS
simulation systems. nullimulators for individual constellations, regional
augmentation systems and hybrid positioning are also available nullsee
the Solution nullirectory for details.null
Page nullSPIRENT eBook
Spirent GSS6300 Multi-GNSS Signal Generator: The ideal solution for
high volume, Multi-GNSS manufacturing environments.
Software
SimGEN™: A fully flexible software suite designed for nullnulluse.
SimGnullnulloffers comnullete, flexible scenario generation canullbility
including control of the constellations, nullonullgation, terrain
obscuration, antenna nulltterns, multinullth, vehicle tranullctory and a
range of error models.
Spirent TestDrive-GNSS: A fully automated nullrformance testing
solution for GNSS-enabled enullinullent. nullt wornull with the GSSnullnull
and GSSnullnull series of Snullrent Multi-GNSS simulators to create an
integrated test solution that enables nullrformance characterisation of
GNSS receiver enullinullent by means of null simulation. nullt is comnulltible
with Snullrentnulls SimGnullnullnull simulation software.
Page 31SPIRENT eBook
nullor more comnullehensive testing, Snullrent also offers nulloducts that
simulate additional system elements simultaneously with the GNSS
constellation signals, such as inertial sensors, various automotive
sensors, Assisted Gnull null-GnullnullnullAssisted GnullnullASS null-GnullnullASSnulldata,
SnullS and GnullS augmentation system signals, interference signals,
GNSS nullecord nullnulllaybacnulland nulli-nulli nullositioning.
nullor more comnullehensive testing, Snullrent also offers nulloducts that
simulate additional system elements simultaneously with the GNSS
constellation signals, such as inertial sensors, various automotive
sensors, Assisted Gnull null-GnullnullnullAssisted GnullnullASS null-GnullnullASSnulldata,
SnullS and GnullS augmentation system signals, interference signals,
GNSS nullecord nullnulllaybacnulland nulli-nulli nullositioning.
nullor more information, read our eboonull nulloosing a GNSS simulator .
Page 3nullSPIRENT eBook
Where Next?
nullf you found this enullok of interest, you may now like to do one of the
followingnull
null nullisit our nullesources page to browse our other enulloks and nullpplication
Notes on relevant topics.
null nullead the Spirent GNSS nulllog to keep up with news and insights on the
latest GNSS developments.
null nullmail us for more information at gnss-solutionsnullpirent.com
Share this enullok on your favourite social media platformnull
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Spirent
+44 1803 546325
globalsales@spirent.com
www.spirent.com/positioning
Spirent Federal Systems
+1 714 692 6565
info@spirentfederal.com
www.spirentfederal.com
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About Spirent
nullpirent nulls been tnull global leader in nullnull testing for 25 nullears. nullpirent delinullers
nanullgation and positioning test enullipment and sernullces to gonullernmental agenciesnull
manullr mannullactnullersnullintegratorsnulltest facilities and space agencies worldwide.
