Testing Multi-GNSS in a Production Environment: From GPS to Compass

Many of today’s commercial and consumer devices incorporate satellite navigation and positioning functionality, and many now support additional satellite navigation systems as well as GPS.
Manufacturers need to be able to specify and run functional tests on finished products to ensure they perform to the OEM’s specification. But how do you effectively test their ability to handle GPS, GLONASS, Galileo and other satellite signals without slowing down production?
Download a free eBook to discover how a new generation of RF simulators enable manufacturers to apply rapid, accurate functional testing to GNSS-enabled products at the end of the production line.
Topics covered include:
- Challenges for manufacturers in testing multi-GNSS navigation and positioning devices
- The risks and limitations of using “live-sky” signals for manufacturing test
- Drawbacks of using parametric test equipment for functional production testing
- Using the new generation of RF simulators for fast, accurate production testing
Simply enter a few details opposite to receive your free eBook from Spirent, the leader in GNSS testing.
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
Testing Multi-GNSS in a Production Environment:
From GPS to Compass
A Spirent Guide for Manufacturers of GNSS-Enabled Devices
As more commercial products offer satellite navigation and positioning
functionality, testing these capabilities at the end of the production
line is critical to delivering a high-quality product.
nullut nullth multiple satellite navigation systems nonullavailable nullncluding
GnullnullnullS, GnullnullASS, and the forthcoming Galileo and nullmpass, as
nullell as smaller regional systemsnull performance-testing of devices nullth
navigation and positioning capabilities is becoming more complenull
nullis eboonullrevienull the current challenges for manufacturers, and
enulllains nully null simulation nullth test equipment designed specinullally
for the production environment is the most efnullient and most cost-
effective solution.
Page 2SPIRENT eBook
Improved coverage and accuracy
nulle shift from individual satellite navigation systems using Gnull
to nenull-generation receivers capable of enullloiting multiple global
navigational satellite systems nullulti-GNSSnulloffers a host of
benenulls in terms of improved coverage and accuracy and in nenull
services.
nullonullever, this snulltch to multi-GNSS dictates that manufacturers
tanull a different approach to testing their products to ensure
that they nullll function as desired, regardless of
nullich satellite signals can be acquired at any
given time. And that nenullapproach has to run
throughout the lifecycle of the product from the
research and development lab right through to
the end of the production line.
SPIRENT eBook
Quality control is king
nullne thing is certainnullthere is no nully any manufacturer can get
anully nullth releasing faulty or poor-performing products to marnullt.
nullodaynulls tech-savvy consumers nullll be quicnullto spot any failing
product, and easy access to social media allonull any disgruntled
user to spread the nullrd far and nullde. As every
smartphone manufacturer nullonull, hard-nulln
brand reputations can be destroyed in a
matter of nulleenull.
Page 4
Absolute quality control is essential, from goods-innullrd testing
right through to nullal manufacturing test. And the crucial part of
this cycle is at the end of the production line, because no matter
honullgood the quality control upstream, only by testing the nullished
product can manufacturers be connullent that the product nullll nullrnull
as promised nullen it gets into the usernulls hands.
Page
SPIRENT eBook
Time is money
nullt goes nullthout saying that the manufacturing test for any piece of
equipment needs to be specinulld long before the equipment moves
into production. nullndeed, it nullll probably be derived from some of the
tests that nullere used in the development and validation of the product.
nullut replicating the same tests that nullere carried out during
nullD and validation is completely inappropriate at the end
of the production line. nulle tests tanull too long, and are far
too detailed for this stage of the product lifecycle, nullere
all thatnulls needed is connullmation that the product nullrnull to
its stated specinullation..
Page nullSPIRENT eBook
At the same time, production testing still needs to be
comprehensive and rigorous. nulle tests must enullercise all the
circuitry of the unit so that the manufacturer can be connullent
that the equipment nullll operate as enullected nullen the user
tanulls it out of the bonulland snulltches it on for the nullst time null
nullerever they are in the nullrld.
nullat is the one nulltestnullnullere there is
no enullcuse for failurenull
SPIRENT eBook Page null
Production testing GNSS receivers
As nullth any functional testing, testing a GNSS receiver on the production
line involves applying a nullonull stimulus and observing the response.
nullf the response is nullthin acceptable bounds the product passes the testnull
if the response is outside those bounds the product fails.
Page nullSPIRENT eBook
nulle response to the stimulus may simply be a trigger signal or an
alarm, or it may be some variable output that can be measured for
the purposes of the test. nullut nullatever the enullected result, it is
essential that the stimulus is accurate and repeatable so that the
response can be gauged against a nullonull standard.
Page nullSPIRENT eBook
The production environment
nullonullever, the production environment is hardly an ideal place to be
testing any piece of sensitive null equipment, much less one that is
designed nullth the necessary sensitivity to capture signals from distant
navigation satellites. Not only nullll the end-of-line test equipment be
indoors, it nullll be in an electrically noisy environment, nullth other null
signals nulloth intentional and accidentalnullpervading the air.
Page nullSPIRENT eBook
And even if the equipment is tanulln outside to test nullhich slonull
donull productionnull therenulls no control over the signals and noise
in the nullive snullnullenvironment, no ability to repeat the same
conditions for every unit, and no nully to test the unit nullth all
of the different satellite systems itnulls intended to nullrnullnullth nullas
some nullll not be visible at the test location.
A far more robust and efnullient
approach is to apply a controllable
and repeatable GNSS or multi-GNSS
stimulus directly to the equipment,
rather than use the equipmentnulls
antenna nullth ever-changing
and uncontrollable nullive
snullnullsignals.
Page null
The multi-GNSS challenge
A further problem is that nullile systems such as GPS, GLONASS,
Galileo, and Compass are functionally similar, there are manullr
differences in the nully they go about their respective tasnull. Different
constellations broadcast on different frequencies. Modulation
schemes differ. nullimebases differ. Different systems even use different
mathematical models for ionospheric modelling.
Page nullSPIRENT eBook
So the multi-GNSS receiver nullll have some different
circuitry associated nullth each satellite system.
nullonullever, those circuits that are shared betnulleen
systems may nullrnulldifferently depending on the
signals being received. A component such as a
clocnullmight be common to both Gnull and GnullnullASS
circuits, but nulluld be driven differently depending
on the signal being received at any given time.
nullerefore, the nullal production test sequence
for any multi-GNSS receiver nullll need to enullercise
all of this circuitry so that the manufacturer can be
connullent it nullll operate as required nullth each GNSS.
Page nullSPIRENT eBook
The simulation solution
nulle only effective and rigorous nully of applying the requisite signals
to a receiver at the end of the production line is to use a radio-
frequency nullnull simulator capable of simulating signals from multiple
GNSS systems nullfrom Gnull to GnullnullASS, Galileo and beyond. nullappily,
todaynulls simulators can be programmed to supply Gnull, GnullnullASS and
Galileo signals individually or in combination. nullatnulls more, a suitable
simulator nullll later be upgradeable to simulate other GNSS signals null
including nullinanulls nullmpassnulleidou system and additional
Galileo satellites nullas soon as they have been
denulled by their system operators.
SPIRENT eBook
Simulators designed nullr production test
nulln the past, manufacturers nullth a commitment to robust production
testing may have struggled to use complenull parametric simulators
intended for nullD labs and military use. nullut today, there is a nenull
generation of multi-GNSS simulators designed specinullally for
production environments.
Page nullSPIRENT eBook
nullese nenullsimulators nullll conduct a quicnullbut thorough
functional test of every unit coming off a production line. nulley
are programmable to run through a denulled series of tests
automatically, delivering an accurate passnullail result nullthout slonullng
donull production. nullatnulls more, they are much less enullensive than
parametric test equipment and slot easily into the production test
infrastructure.
Page nullSPIRENT eBook
Consistency nullthout complenullty
nullodaynulls nenull-generation multi-GNSS simulators enable
manufacturers to replicate the essential functional tests
conducted at earlier stages of the product lifecycle, to ensure
a consistent test approach nullthout the need to invest in
high-end equipment or operator
snulllls. nulley come nullth softnullre
functionality that allonull specinull
signal scenarios to be denulled and
the ability to combine a range
of simple tests into a single
routine that can be run
time and time again nullth
absolute repeatability.
SPIRENT eBook
Sequences can be compiled that combine sensitivity and dynamic
positioning tests in a single high-speed run, encompassing all different
GNSS circuits nullthin a receiver. nullf the receiver operates normally over
the nullole of the test sequence, the manufacturer can be connullent that
it nullll be null for purpose once the end user tanulls it out of the bonull
Page nullSPIRENT eBook
Bringing it all together
nullt is probable that the GNSS receiver nullll not be the only part of
the equipment that requires acceptance testing. nullor enullmple, many
consumer devices incorporate multiple types of radio receiver
nullncluding nulli-nulli, nullluetooth and null radionullalongside the GNSS receiver,
often using the same antenna for all of these functions. So itnulls
important to choose a multi-GNSS simulator that can be integrated
nullth other test equipment in order to create a complete functional
test system for the nullole equipment.
Page nullSPIRENT eBook
nulle combined test setup nullll feature dedicated nullturing that
nullll allonullaccess to the productnulls receiver circuitry, speeding
product throughput, minimising test time and enabling
complenullnullf-thennulltest scenarios that can enullercise multiple
functions nullnd multiple GNSS receiver circuitsnullin a single
softnullre-controlled test routine.
Page 2null
The science onullcompliance
nullith GNSS receivers nullding increasing application in mission-critical
and safety-of-life applications, product certinullation may nullell demand
nullnull testing of all units. And in the case of multi-GNSS receivers
capable of nullrldnullde application, the certinullation procedure can only
become more complenull
Page 2nullSPIRENT eBook
nullt is only by applying the required production tests using a multi-
GNSS simulator that a manufacturer can be seen to be applying due
diligence in ensuring continuing compliance nullth both global and
local standards applicable in all marnullts for the product in question.
Spirent GSSnullnull
Multi-GNSS signal Generator
provides a single channel
of GnullnullnullS, GnullnullASS
andnullr Galileo null signals
for production testing on
commercial GNSS receivers
Spirent GSSnullnull
Multi-radio nullreless
connectivity tester for
rapid functional testing
of radio-enabled devices
Spirent GSSnullnullM
Multi-channel GNSS
simulator.
nullts eight channels of
operation can simulate nullnull
Enullsignals from GnullnullnullS,
GnullnullASS and Galileo
to test the fundamental
positioning capabilities of
any GNSS device
Spirent GSS42null
Gnull nullroductionnullield nullest
Multi-nullannel Simulator
Page 22SPIRENT eBook
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Spirent has been the global leader in GNSS testing for null years. Spirent delivers
navigation and positioning test equipment and services to governmental agencies,
manullr manufacturers, integrators, test facilities and space agencies nullrldnullde.