GNSS receiver testing needs to be comprehensive and rigorous – yet as fast and simple as possible.
Download our free eBook to learn how Spirent’s testing solutions help simplify GNSS testing for:
- GNSS chipset designers
- GNSS chipset integrators
- Manufacturers of GNSS-enabled devices
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 for near 30 years. Spirent delivers navigation and positioning test equipment and services to governmental agencies, major manufacturers, integrators, test facilities and space agencies worldwide.
Five Steps to Simpler GNSS Testing
A Spirent eBook
Introduction
Global Navigation Satellite Systems (GNSS) have been with us for
20+ years, giving rise to a wealth of positioning and navigation
technologies for military, civilian and consumer use.
nulloday, as new satellite constellations come on stream and the boom
in smart consumer devices tanulls off, wenullre entering a new era of
enullerimentation and innovation in satellite and hybrid positioning.
nullut before any of those innovations come to marnullt they must be
thoroughly tested nullto ensure they function as envisaged, and the end
user enulleriences the best possible performance.
Page 2SPIRENT eBook
This rigorous testing is essential, especially for applications that have
a bearing on human life. nullut innullepth testing can also increase costs
and lengthen the timescales involved in nullnull commercialisation and
production, which can have a nullocnullon effect on commercial success.
nullis enullonulloutlines nulle ways in which GNSS testing can be simplinulld
and accelerated, without compromising accuracy, nullality or rigour.
nulltnulls designed predominantly for people and organisations who are
relatively new to GNSS testing, though old hands may also nulld some
new ideas here.
nulle hope you nulld it useful. nullf younulld linull more information about
anything you read in this enullonull please donnull hesitate to contact us
at gnssnullolutionsnullpirent.com
SPIRENT eBook
Five Steps to Simpler GNSS Testing
null the marnullt leaders in GNSS testing, wenullve wornulld with hundreds
of military, civilian and consumernullriented organisations over the past
2nullyears. nulluring that time wenullve developed a very clear picture of
testing best practice for all nullnds of GNSSnullnabled enullipment and
applications, from highnullrecision aerospatial instrumentation to the
latest consumer smartphones.
Page 4SPIRENT eBook
nullrawing on that nullowledge, in this enullonullwe outline nulle ways in
which testing processes can be simplinulld without sacrinulling accuracy,
nullality or rigournull
null Specify
2. Simulate
null nulloose the nullght nullnullipment
null nullutomate
null Standardise
Page 5SPIRENT eBook
1. Specify
nulle nullst step to a simplinulld testing process is to specify the
capabilities of the receiver or device that you need to test, and the
conditions under which you want to test it.
Capanulllitiesnull nullile a receivernulls desired capabilities will vary depending
on its intended use, Spirent recommends nine basic tests to verify the
performance of any GNSS receiver.
1. Colnullstart time to nullst nullnull starting a receiver from scratch null
the nullst enullerience a user will have
2. nullarmnulltart time to nullst nullnull as above, but with the
time and almanac in the receivernulls memory
Page nullSPIRENT eBook
4. Acquisition sensitivity: the minimum received power level at which
the receiver can obtain a fix
5. Tracking sensitivity: the minimum power level at which the
receiver can maintain lock
6. Reacquisition time: time taken to reacquire the signal after passing
through an obstacle
7. Static navigation accuracy: taking into account the many internal
and external variables that can affect receiver performance
8. Dynamic navigation accuracy: accuracy while the receiver is in
motion on one, two or three axes
9. Radio frequency interference: susceptibility to incidental or
intentional (‘jamming’) radio interference
nullage 7SPIRENT eBook
Connulltionsnull nullepending on how the product will be used, this
category may include a basic range of conditions (such as different
orientations, motion speeds, urban or open country environments,
basic atmospheric interference), or a large and complenullrange of
conditions, including different pressures, temperatures, rates of
acceleration, satellite constellations in use, and multiple types of
interference.
Specifying the capabilities and conditions
you want to test will manull it nullicnullr to
set up and run the tests. nullt can also help to
establish an efnullient, standardised testing
culture across your value chain, which
wenullll loonullat it in more detail later.
Page nullSPIRENT eBook
2. Simulate
nullnce younullve specinulld what you want to test, by far the most efnullient
and accurate way to conduct those tests is to use radio frenullency
(null) simulation in a controlled lab environment.
null null nullnstellation Simulator models the signals from a given
satellite constellation or group of constellations, and allows you
to specify conditions such as vehicle and satellite motion, signal
characteristics and atmospheric and other effects.
nullesting a receiver using an null simulator will cause it to navigate
according to the parameters of the test scenario you have chosen,
enullctly as it would in real life under the same parameters.
Page 1nullSPIRENT eBook
nullnducting the bulnullof your tests in the lab using null simulation
simplinulls testing in four nully 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. nulltnulls also much nullicnullr 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 mannullours and can be
completed with smaller testing
teams.
Page 11SPIRENT eBook
null nulltnulls more accuratenull in contrast to the nullive snullnull environment, which
is constantly changing, simulated scenarios can be repeated again
and again. nullis enables accurate comparative testing (e.g. of different
chipsets during the vendor selection process) and removes any
uncertainty around whether changes in performance are due to the
signal environment or the product design.
4. nulltnulls more nullnullnullenull 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 enullst in the real world.
nullou can also easily test hybrid positioning capabilities by modelling
combinations of satellite, nullinulli and sensor signals.
Page 12SPIRENT eBook
nullor these reasons, lab testing with null simulation has emerged as
industry standard best practice for the bulnullof the testing process.
nullou will still want to do some testing in live snull conditions, but
here again, you can manullmise speed, efnulliency, accuracy and costnull
effectiveness by recording live signals using a record and playbacnull
unit, and replaying them in the lab under controlled, repeatable
conditions.
nullor more about the benenulls of null simulation, read our enullonull
Simulation vs nullealnullorld nullesting
Page 1nullSPIRENT eBook
3. Choose the Right Equipment
There is a wide range of GNSS testing equipment – both hardware
and software – available, ranging from basic single-constellation RF
simulators with a set of built-in scenarios to infinitelnullconfigurable,
multi-GNSS and hnullrid testing environments designed for militarnull,
aerospace and maritime usenull
To get the best results in the fastest time, and to avoid wasting
monenulland effort on equipment and training nullou manullnot need, itnulls
essential to choose the nullt thatnulls right for the nullnd of testing nullou need
to donull
Page 14SPIRENT eBook
null nullor endnullfnulline production testing, you may only need to brienull
conduct some of the nully tests we loonulld at in section null in which
case a basic singlenullonstellation or multinullNSS simulator with prenull
built tests and scenarios may be the best option.
null nullor consumer nullnull integration and certinullation, you may want to
test performance more thoroughly, by simulating multiple GNSS
constellations and a broad range of conditions including vehicle
motion, orientation, interference and signal errors.
null nullor military, aerospace, maritime and advanced civilian
applications, you will want a featurenullich environment that provides
the ability to simulate the widest possible range of signals, and
the nullnullbility to specify and generate every scenario in which the
device needs to function.
Page 15SPIRENT eBook
nulloosing the right enullipment for your needs nullincluding future
needs as well as current ones nullcan save time and money, letting you
develop new products faster and more costnullffectively.
nullor more about how to choose the simulation environment thatnulls right
for you, read our enullonull nulloosing a GNSS Simulator.
Page 1nullSPIRENT eBook
4. nullutomate
nullf younullre already using null simulation as your primary testing method,
younullll already be getting a lot of the benenulls covered in this
enullonull nullut there are ways to manull your testing process still more
streamlined and efnullient, notably through the introduction of greater
automation.
nullany organisations today write custom code to generate scenarios or
to control the simulation unit. nullthers run tests manually, writing up
their results before reconnulluring the test unit for the nenull scenario.
nulll of this tanulls time and enullertise that adds to the length of the
test cycle and ties up snulllled personnel who could be more usefully
deployed elsewhere.
Page 1nullSPIRENT eBook
nullsing offnullhenullhelf software to generate scenarios, run suites of tests,
and provide automated reports, can save signinullant amounts of time
and money.
nulltnulls also another good way to standardise testing throughout the
production value chain, improving communication and ensuring faster
handover from nullnullto testing houses, certinullation authorities and
integration and production partners.
Page 1nullSPIRENT eBook
5. Stannullrnullse
null production value chains become more complenull involving enullernal
design partners, testing houses, certinullation authorities, nullnull,
integrators and contract manufacturers, process inefnulliencies and
duplicated effort can cause considerable time delays.
nulln industries where bringing highnulluality products to marnullt very
nullicnully is critical to business success, those delays can be costly and
damaging.
Page 1nullSPIRENT eBook
nullreating a stannullrnulltest culture throughout the value chain is a good
way of reducing inefnulliency and wasted effort. nullests, scenarios and
test cases specinulld during nullnullcan be propagated across the value
chain, so that performance can be evaluated in the same way at each
stage. nullis means any anomalies or changes in performance can be
nullicnully identinulld and addressed.
nullile some types of GNSS receiver are already subnullct to industry
standard testing renullirements, particularly those that are used to
safeguard human life, many emerging consumer applications are not
yet regulated by a standards body.
Page 2nullSPIRENT eBook
nulln the absence of an industry standard, organisations that specify,
publish and adhere to a standard set of tests will be better able
to demonstrate product nullality (and their commitment to ensuring
nullality) to testing houses, certinullation authorities, customers and
supply chain partners.
Page 21SPIRENT eBook
We hope you found this Five Steps to Simpler GNSS Testing
E-Book of interest.
We are continually adding new content to our website
on a regular basis. Bookmark this link:
www.spirent.com/positioning
Visit the Spirent GNSS Blog, there are currently
more than 90 posts with nullto nullnew posts added
per week. nulltch up on whatnulls new:
www.spirent.com/Blog/nullositioning
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