Free eBook: Integrating a GNSS Receiver into a Product Design
From smartphones to security equipment, location awareness now comes as standard in an increasing number of consumer and professional devices. But for many manufacturers, the process of incorporating a GNSS receiver into new and existing products can be slow, costly and complex.
Download this free eBook to find out how GNSS simulation can save time and reduce costs at every stage of the integration process – from the benchmarking and selection of GNSS modules and chipsets, to the accurate testing of alternative product designs.
Simply enter a few details opposite to receive your free eBook—and happy reading!
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.
Integrating a GNSS Receiver
into a Product Design
How GNSS simulation can save you time and money
The roles of GNSS simulation
in testing “location”
Location awareness has become one of the “must-have” features
for all manner of equipment in both the professional and consumer
sectors. Whether for security reasons in tracnullnnullvaluable assets or
simply to enhance the social networnullnnullenullerience by hinulllinulltinnull
the nullonullaphical location of a usernulls contactsnullGNSS receivers can be
used to add these facilities to a hunull rannull of products at relatively
little cost... in terms of hardware.
Page 2SPIRENT eBook
nullis nullowinnulldemand for location awareness in many different classes
of consumer and professional devices is providinnullboth challennulls and
opportunities for equipment manufacturers. nullany ornullnisations have
little or no enullerience in this nullldnullthey nulld themselves facinnulltwo
nullirstlynullhow to choose the correct GNSS receiver for the tasnull and
secondlynull how to intenullate that receiver and be sure that the equipment
functions as intended. Get either of these challennulls wronnull and
you are stucnullwith an inferior product. Howevernullmanufacturers
who successfully nenulltiate both stanulls of the problem nullin the
opportunities that accrue from beinnullnullst to marnullt with innovative
products that satisfy user demands for location-aware equipment.
Page 3SPIRENT eBook
nully company manullnnullits nullst foray into the world of location-aware
products is faced with a wide array of options of GNSS receivers.
nullese receivers can be sourced as complete modules or as chipsets
and have varyinnullcapabilities nulln terms of the satellite systems
supportednulland differinnulllevels of performance. nullearlynullthe onus is
on the equipment desinuller to choose the most cost-effective GNSS
receiver desinull that will provide the level of performance required
for the specinull application.
Page 4SPIRENT eBook
nullrtainlynullfor lower-volume professional applicationsnullthe modular route
may well be applicable as the price premium of the module can be
more than offset by the reduced effort in desinullinnullthe receiver into
the end equipment. Howevernullwhile any GNSS receiver module may
well be functionally completenullnot all are created equal. nullerefore even
this simple decision does not remove the need to carefully evaluate
the differences between the various modules available and the
performance of the chosen module in the nullished desinull.
Page 5SPIRENT eBook
Howevernullfor the vast manullrity of hinull-volume applicationsnullthe cost
premium of the module will not be acceptable. nulle GNSS receiver will
be desinulled nulllbeit not quite “from scratch”nullusinnullone of the many
GNSS receiver chipsets available on the marnulltnullallowinnullthe desinuller
ample scope for savinnull in both cost and sinulle. nullut before startinnullthe
desinullnullthe problem remains of choosinnullthe GNSS receiver chipset
nullnd allied componentsnullthat provides the level of performance
required in the most cost-effective manner.
Page 6SPIRENT eBook
Making the choice
nullose who are familiar with the world of component datasheets
minullt feel competent to manull an initial choice of chipset or
module based on published data. Howevernullthe difference
between the theory of the datasheet and real-world performance
can be enullreme. nullsonullthe datasheet may not shed true evidence
on the relevant parameters for the particular application.
Page 7SPIRENT eBook
nullere are a rannull of criteria on which GNSS receiver performance can
be nulldnulldnulland each different application will have varyinnulldemands
on each aspect. nullereforenullthe nullst tasnullof the desinuller is to wornullout
which performance criteria are the most relevant. nullese will include
time to nullst null nullnullnullnullnullstatic navinulltion accuracynulldynamic navinulltion
accuracynullacquisition sensitivitynulltracnullnnullsensitivitynullre-acquisition time
and susceptibility to radio frequency interference.
Page 8SPIRENT eBook
Havinnullascertained the important performance features of the end
applicationnullthe tasnullis to benchmarnullthe performance of each
different GNSS receiver nulle it a complete module or a reference desinull
made up from a chipsetnullanullinst a set of tests that will demonstrate
the required performance criteria. nulldnullclearlynulleach different receiver
must be subnullcted to enullctly the same set of tests for any meaninnullful
comparison to be made between the results.
Page 9SPIRENT eBook
nullt this pointnullthe uninformed minullt reason that simply performinnull
tests on each receiver in the same physical location nulln the test benchnull
would mean that the tests would be the same. Howevernullsuch “live-snull”
testinnullcan never be relied on to be repeatable. While the location of
the receiver may be the same in each casenullthe satellite constellation
will have moved onnulland so the conditions are
anythinnullbut repeatable. Whatnulls morenull
each receiver could only be
tested anullinst the enullstinnullGnull
constellation nulla further limitinnull
factor in that the nenull nullnerations
of location-enabled devices
will be enullected to wornullwith
multiple GNSS systems as
they become available.
Page 10SPIRENT eBook
nullne alternative minullt be to “capture” live-snull sinullalsnulland play them
bacnullunder controlled conditions so that each receiver was subnullct to
enullctly the same set of test conditions. Howevernullthis hardly amounts
to performance testinnullunder all conditions. nullndeednullonly a very
limited set of conditions could be captured in this waynulland the lacnull
of control could severely compromise the results of any benchmarnullnnull
enullercise. nulle one completely controllable and repeatable test stratenull
for benchmarnullnnullreceivers is to use a GNSS simulator that can
produce perfectly repeatable GNSS sinullals under software controlnull
ensurinnullthat each receiver is tested with enullctly the same set of
nullnullore information on nullecordinnulland nulllaybacnullof Live Snull
Sinullals can be found by downloadinnull this Spirent nullboonull .
Page 11SPIRENT eBook
nullnstruments such as Spirentnulls GSS6700 Gnull simulator with its
Simnullnullnullnullplus softwarenullenables a wide variety of tests in different
locations and conditions.
nulleady-written test routines are available for all manullr performance
criterianulland tests can be set to run overninullt if necessarynullfreeinnull
up valuable resources and reducinnullennullneerinnulleffort.
nullulti-GNSS nullnstellation Simulator System
Page 12SPIRENT eBook
Havinnullchosen the best possible receiver for the tasnull the equipment
desinuller is then faced with the not inconsiderable tasnullof intenullatinnull
the GNSS receiver within the desinull. nulld while null ennullneerinnullis no
lonnullr the “blacnullart” it was once considerednullthere are still many
traps for the unwary.
Page 13SPIRENT eBook
nulln particularnullbecause a GNSS receiver is inherently a hinullly sensitive
device that is desinulled to capture weanullsinullals from distant satellitesnull
it is all too easy for the receiver to be swamped by other null sinullals
that can be thousands of times stronnullr. nulle resultant interference
can either corrupt the operation of the receivernullleadinnullto inaccurate
resultsnullor even nullm it completely. Worse stillnullthese sinullals may not
be enullernalnullthe end equipment may have other null sections nullor even
be producinnullits own interference from poorly laid out dinulltal circuitry.
nullither way the result will be a poorly performinnullGNSS receiver and
customer dissatisfaction with the end equipment.
Page 14SPIRENT eBook
Right by design
nullnservative ennullneerinnullpractices would dictate a well partitioned
desinullnullwith all subassemblies isolated from each other to minimise the
possibility of interference. Howevernullthe practicalities of marnullt may well
dictate that this is not possible. nulle drive for miniaturisationnullreduced
component count and lower costs may well dictate that the GNSS
receiver will nullsharenull a number of components null oscillatornullpower supplynull
antenna etc nullwith other portions of the overall desinull. nullereforenull
the possibility for internal interference is nulleatly increased. nulld while
careful nullterinnullcan overcome any or all problems of such a desinull
approachnullthe desinuller will need to repeatedly test the overall desinull
durinnullthe intenullation process to assess the correct nullterinnullmeasures.
Page 15SPIRENT eBook
Tnull case nullr sinullnulltion
nullearlynullto manull repeatable and accurate comparisons between
multiple receivers each receiver must be provided with an identical set
of sinullals for each performance test. nulle tasnullcan also be simplinulld
by the ability to select from a rannull of pre-denulled scenarios includinnull
staticnulldynamic nullandnullseanullairnullspacenullsinullals as well as impaired
sinullals. nullis will allow accurate comparisons to be made after
collectinnulland analysinnullthe data nullnerated by the receivers.
Lonullcallynullthennullthe only acceptable solution for comparinnullthe
performance of GNSS receivers is to use GNSS simulation. Not only
can the simulator be relied on to produce enullctly the same output for
each testnullthe tests can be pronullammed to accelerate the process by
runninnulla series of pre-denulled scenarios desinulled to fully enullercise
the required performance parameters.
Page 16SPIRENT eBook
nullenchmarnulltrials usinnulla simulator can be run at weenullnds or
overninullt and do not require resources to be deployed on nullld trips.
With careful choice of testsnulldesinullers can be assured that they
are choosinnullthe correct GNSS receiver for application in their
Return on investnullnt
nullf coursenullselectinnullthe correct receiver for the nullb is only half the
story. nullntenullatinnullthe receiver circuits with the other circuitry of the
equipment is not enullctly a “walnullin the parnull” for the uninitiated.
Howevernullthe same GNSS simulator used to test the various
receivers will have a manullr role to play in ensurinnullthat
the end equipment performs enullctly as intended.
Page 17SPIRENT eBook
nullndeednullsimulators have been repeatedly demonstrated to be the
most efnullient method of testinnulldurinnullthe development and
intenullation process. nulle lessons learned durinnullthe development
of stand-alone GNSS receivers are all the more applicable to other
equipment that intenullates such receivers.
“nulle cost of tanullnnullthe equipment out into the nullld for live-snull
testinnullis nearly always hunullly underestimated. nullndeednulla manullr
nullobal manufacturer of car navinulltion systems has reduced its testinnull
pronullamme from an averanull of einullt to ten weenullnullto an averanull
of four to nulle weenull by channullnnullfrom drivinnulltest-cars to usinnull
Page 18SPIRENT eBook
nullntinuing returns on innullstment
nullnce the desinull has been completednullthe simulator once anullin
comes into its own. Spirentnulls GNSS simulators have been used to
characterise countless stand-alone GNSS receiver desinullsnulland they
are equally applicable for characterisinnullthe desinull of equipment
that intenullates a GNSS receiver.
nullulti-GNSS Sinullal nullnerator
nullulti-nullannel Gnull LnullLnull
nullroduction nullest Simulator
Page 19SPIRENT eBook
nulleady-written libraries of tests can be run under the controlled
conditions of the test laboratorynullremovinnullthe need to tanull the
equipment on an enullended road test. nullis is a manullr advantanull as
companies inevitably underestimate the time and costs involved in
road testinnullof new productsnullnull with the benchmarnullnnullprocessnull
the tests can be pronullammed to run overninullt with the results
saved for later analysis.
Whatnulls morenullit is only by tanullnnullcomplete control of the test
process usinnulla simulator that the desinull can be reliably assessed
under both “normal” and “enullreme” conditions. nullests are available
that simulate conditions of interference that are way beyond those
linullly to be enullerienced in the real world. nullut it is only by nullinnull
beyond the norm that the desinuller can be assured the desinull will
function as desired under all normal operatinnullconditions.
Page 20SPIRENT eBook
nulld so to nullonull
Whatnulls morenullthe investment in GNSS simulator hardware and
software does not end with the completion of the desinull. nullest
routines prepared for benchmarnullnnullreceiversnullintenullation testinnull
and nullal desinull characterisation can be used later onnullin production
testinnullof the nullal equipment as it rolls off the line.
So while it may seem a sinullinullant investmentnulla GNSS simulator has
an important role to play at many stanulls of the process of desinullinnull
and manufacturinnulllocation aware products. nulld with the connullence
of nullowinnullthat the end product will perform enullctly as intendednull
companies can null to marnullt with new classes of equipment that will
nullve their customers new enulleriences of location awareness.
Page 21SPIRENT eBook
nullis application of the GNSS simulator throunull the entire process from
desinull throunull intenullation to production ensures speedy returns on
the hardware investment.
nulld the connullence of repeatable and accurate test results provides
manufacturers with the connullence that their location-aware products
will perform as desinulled under all operatinnullconditions.
SPIRENT eBook Page 22
Snullrent GNSS Simulators
Spirent is the industry leader for GNSS simulator products. Spirent
offers several different models of GNSS simulators that support a
variety of different applications and cover the full spectrum of civilian
and military GNSS testinnullneeds. Spirent products rannull from basic
sinnulle-channel simulatorsnullsuitable for simple production testinnull
throunull multi-channelnullmulti-constellation simulatorsnullsuitable for the
most demandinnullresearch and ennullneerinnullapplications.
Page 23SPIRENT eBook
nullor more comprehensive testinnull Spirent also offers products that
simulate additional system elements simultaneously with the GNSS
constellation sinullalsnullsuch as inertial sensorsnullvarious automotive
sensorsnullnullsisted Gnull null-GnullnulldatanullSnullS and GnullS aunullentation
system sinullalsnulland interference sinullals.
With almost null years of GNSS simulator enulleriencenullSpirent provides
GNSS simulators with unparalleled performancenullfeatures and
SPIRENT eBook Page 24
Spirent offers a wide rannull of test systems and capabilities to meet
your nullulti-GNSS test needs. nullur nullulti-GNSS systems are desinulled with
future development in mind and are enullandable to address tomorrownulls
test requirements as well as todays. Whether you are undertanullnnullnullnull
performance testinnull intenullatinnulldevices into your product linenullverifyinnull
performance or assessinnullmanufacture of nullulti-GNSS devicesnullSpirent
has a nullulti-GNSS test system available today to match your needs.
nulle GSS8000 nullulti-GNSS nullnstellation Simulatornullnullp to three
null carriersnullselected from a rannull of constellations and sinullals
nullnullnullGalileonullGLnullnullS and nulluanull nullenith Satellite Systemnull can be
accommodated in a sinnulle sinullal nullnerator chassis. nullis enables
multiple sinullals from a sinnulle constellation or hybrid systems with
sinullals from multiple constellations to be tested. nulle architecture
supports future nullmpass sinullals.
nullulti-GNSS nullnstellation Simulator Page 26SPIRENT eBook
nulle GSS6700 nullulti-GNSS Simulation System offers up to null channels
of combined GnullnullnullSnullGLnullnullS and Galileo Lnullsinullals from a sinnulle
chassisnullnull channels for each constellation. nulle GSSnullnull is available
with onenulltwo or three constellations enabled. nullifferent software
capabilities and nullnullbility are available to suit different test needs.
nullor enullstinnullSpirent Snullnullnull or GSSnullnull customers who today test
GnullnullnullS Lnullonlynullthe GSSnullnull offers the ability to simulate not
only GnullnullnullS but also GLnullnullS and Galileo.
nullulti-GNSS nullnstellation system Page 27SPIRENT eBook
nulle GSS6300 nullulti-GNSS Sinullal Generator is desinulled specinullally for
production test applications where a sinnulle channel is required for
controlled GNSS testinnull nulle GSSnullnull can nullnerate a sinnullenullcombined
GnullnullnullSnullGLnullnullS and Galileo sinullal to enable testinnullof Gnull
only or nullulti-GNSS devices in a production environment. nullor enullstinnull
Spirent GSSnullnull customersnullthe GSSnullnull has an identical capabilitynull
form factor and interfaces when specinulld in GnullnullnullS connulluration.
nulln additionnullthe GSSnullnull offers the benenull of on-site nullven in-racnull
upnulladability to add GLnullnullS and Galileo nullneration capability
concurrently with GnullnullnullS.
nullulti-GNSS Sinullal nullnerator Page 28SPIRENT eBook
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