Free eBook: Testing Multi-GNSS in an R&D Environment

Satellite navigation systems that support multiple constellations can provide much better coverage and accuracy than receivers that rely on GPS only. But moving to a multi-GNSS model requires rigorous testing for different constellations and conditions at the R&D stage.
Download a free eBook to discover best-practice approaches to multi-GNSS testing in the R&D lab, including:
- Basic and advanced tests for accurate multi-GNSS testing
- The advantages of RF simulation over live-sky testing
- The benefits of using a multi-channel GNSS simulator
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.
FREE eBook: From GPS to Multi-GNSS
The shift from individual satellite navigation systems using GPS to next-generation receivers capable of exploiting multiple global navigational satellite systems (Multi-GNSS) offers a host of benefits in terms of improved coverage and accuracy and in new services.
However, this switch to Multi-GNSS dictates that manufacturers take a different approach to testing their products to ensure that they will function as desired, regardless of which satellite signals can be acquired at any given time. And that new approach has to start at the beginning of the product development process – in the research and development lab.
This eBook provides an insight into some of the testing issues faced by GNSS receiver developers and how Multi-GNSS simulation can help designers create receivers that can perform reliably anywhere in the world.
Find out more, download the FREE eBook.
Your Spirent GNSS team
Testing Multi-GNSS
in an R&D Environment
From GPS to Multi-GNSS
A host of benefits
The shift from individual satellite navigation systems using GPS
to next-generation receivers capable of exploiting multiple global
navigational satellite systems (Multi-GNSS) offers a host of benenulls
in terms of improved coverage and accuracy and in nenullservicesnull
nullonullevernullthis snulltch to Multi-GNSS dictates that manufacturers tanull
a different approach to testing their products to ensure
that they nullll function as desirednullregardless of
nullich satellite signals can be acnullired at
any given timenullnulld that nenullapproach has
to start at the beginning of the product
development process nullin the research
and development labnull
SPIRENT eBook
So many systems
The problem is that nullile systems such as GLONASSnull Galileonullthe
soon to be upgraded GPS and Compass are functionally similarnullthere
are manullr differences in the nully they go about their respective tasnullnull
nullifferent constellations broadcast on different frenullenciesnullModulation
schemes differnullTimebases differnullnullifferent systems even use different
mathematical models for ionospheric modellingnull
Page 3SPIRENT eBook
null a resultnullthe range of tests renullired in the R&D laboratory
is considerably nullder than those traditionally used in the
development of “vanilla” GPS receiversnull
Page 4SPIRENT eBook
The simulation solution
null Multi-GNSS simulator provides an effective and efnullient means
to test GNSS receivers and the systems that rely on themnullnullith a
Multi-GNSS simulatornullevery time a test scenario is runnullthe signals
produced are identicalnullThe scenario nullll start at the same time and
on the same datenulland the satellite positions nullll be identical nulleven
donull to the relative phase offsets betnulleen the different signalsnull
Page 5SPIRENT eBook
nulln this nully you can guarantee that the receiver is being simulated
nullth exactly the same signals every time the test is runnullnullnly this nully
can you fully determine any improvement (or othernullse) the design
alterations have madenull
nullatnulls morenulla suitable simulator nullll be capable onullupnullanullnnull to
simulate other GNSS signals as soon as they have been denulled by
the system operatornull
Page 6SPIRENT eBook
The tests required
nulln the development process of any GNSS receivernullthere
are tnull distinct levels of tests that nullll be appliednull
Page 7SPIRENT eBook
nullasic tests are those that exercise the simplest underlying
functionality of the receivernull
nulldvanced tests cover those that recreate nullunusualnullsituations
and also those that exploit novel applications outside the basic
functionality of the receivernull
Page 8SPIRENT eBook
Basic R&D testinnull
nulln testing the underlying functionality of any GNSS receiver design
in the laboratorynullit is essential that the enullipment is subnullcted to a
nullonull and repeatable stimulus so that the correct response can be
assessed and the performance can be adnullsted accordinglynull
Page 9SPIRENT eBook
nullt the simplest levelnullthe receiver is supplied nullth a reference
signal nullth a navigation message consistent nullth the relevant nullnull
or interface control documentnullThis allonull the designer to verify the
receivernulls algorithms for decoding the messages and recovering time
synchronisationnullnullt also allonull the designer to optimise the accuracy
and sensitivity of the receivernull
nullther basic tests at this level include the receivernulls one pulse
per second (nullPS) performancenulltogether nullth static and dynamic
accuracy and time to nullst null nullnullnull null
Page nullSPIRENT eBook
Adnullanced R&D testinnull
The nully to any advanced nullnulltesting is the ability to simulate a
specinull scenario nullth absolute repeatability so that adnullstments
can be made and the test can be re-
appliednullThese scenarios can be of
almost any naturenulland nullile each one
may be unlinullly to occur in real lifenull
a reliable Multi-GNSS receiver nullll
be expected to perform reliably
under all possible conditionsnull
Page nullSPIRENT eBook
nullearlynullbecause these scenarios are unlinulllynullit is impossible to
nullcreatenullthem in real life nullthout a simulator (let alone recreate them
for a second test)nullThe simulator enables easy creation of a library of
performance tests ready to apply to the receivernull
These tests can then be combined and enhanced to create ever more
complex test scenarios that can be saved and used over again nullth
absolute repeatabilitynull
Page nullSPIRENT eBook
The nullultinullNSS annulle
nullven at the most basic levelnullit is important to test
the Multi-GNSS capabilities of the receivernullThe basic
tests of signal and truth data references should be
repeated for each GNSS nullth nullich the receiver is
intended to operatenullSo (currently) this nullll mean
applying GPSnullGnullnullnullS and Galileo reference
signals and decoding their respective
navigation messagesnull
Page nullSPIRENT eBook
This multiple signal testing nullll also exercise the frenullency agility of
the receiver designnullFor nullile both GPS and Galileo broadcast their
null civilian signals in a band centred on nullnullnullnullnullnullthe GnullnullnullS
civilian signal is broadcast in a band from nullnullMnull to nullnullMnullnull
nulld the ability to apply all these tests from the same simulator nullll
remove a number of potential error sources from the test setupnull
Page nullSPIRENT eBook
Adnullanced nullultinullNSS testinnull
nullne critical difference in testing a Multi-GNSS receiver compared nullth
one destined for use on a single system is in its ability to handle all
the various different models used by each satellite systemnull nulld nullile
GPSnullGalileo and GnullnullnullS use the same co-ordinate framesnullGPS has
its onull timebasenullnullich differs from the other tnull systemsnullnullich
are tied to the global nullC time system null
Page nullSPIRENT eBook
Similarlynullnullile GPS uses the nullobucnullr monulll to correct for errors
induced by ionospheric effectsnullGalileo nullll use the Nenulluicnullmodelnull
Fortunatelynulla Multi-GNSS simulator can account for these differencesnull
and nullll supply the signals exactly as they nulluld appear to the
receiver in the real nullrldnullallonullng nullnulltesting to predict real-nullrld
performance nully in advance of the nullrealnullsignals being availablenull
Page nullSPIRENT eBook
nullinulld messanulls
So nullile the designer nullll nullnt to assess any nenullreceiver
design for its performance against all the standard GNSS testsnull
it is essential that these tests are run for each GNSS for nullich
the receiver is designednull
Page nullSPIRENT eBook
null Time to nullst null
null nullcnullisition sensitivity
null Tracnullng sensitivity
null nulleacnullisition time
null Static navigation accuracy
null nullnamic navigation accuracy
null nulldio frenullency interference
nullut the true Multi-GNSS receiver should be able to produce
nullrnullble results even nullen nullrnullng nullth partial signals from
multiple systemsnullnullt is only by using a multichannel Multi-
GNSS simulator that this performance can be readily assessed
and the design renulled to improve itnull
Page nullSPIRENT eBook
Anulllicationnullnullcific testinnull
nullrtain tests at this stage nullll depend on the intended end
application of the Multi-GNSS receivernullThese might be automotive-
specinull testsnullavionics-specinull tests (nullich might involve the
receiver and its antenna being at any range of angles depending on
vehicle manoevres) or space-specinull testsnull
Page nullSPIRENT eBook
nulln each casenullthe simulator nullll either provide suitable ready-nullitten
testsnullor can be programmed nullth the relevant scenariosnullnullich can
then be replayed nullth absolute repeatabilitynulltime and time againnull
Page nullSPIRENT eBook
Statenullfnullhenullrt simulation
simnullifies R&D
The snulltch from simple GPS navigation to the
use of multiple satellite systems is bringing a nenull
set of challenges to receiver nullsinullers nullnullonullevernull
exhaustive testing in the nullnulllaboratory can give
designers the connullence that their nenullMulti-
GNSS receiver designs nullll perform as intended
once they enter servicenull
The list of tests renullired is extensivenulland
nullive-snullnulltesting using nullrealnullsignals from
nullrealnullsatellites is not an optionnull
Page nullSPIRENT eBook
null multichannel Multi-GNSS simulator nullll allonullall the necessary
tests to be run using signals from single and multiple GNSSsnull
nulld the ability to nullmix and matchnullsignals from different systems
nullll allonulldesigners to create receivers that can perform reliably
anynullere in the nullrldnull
Page nullSPIRENT eBook
Tnull Snullrent GNSS annullnulli-nulli Solutions
Spirent is the industry leader for GNSS simulator productsnullSpirent
offers several different models of GNSS simulators that support a
variety of different applications and cover the full spectrum of civilian
and military GNSS testing needsnull Spirent products range from basic
single-channel simulatorsnullsuitable for simple production testingnull
through multi-channelnullmulti-constellation simulatorsnullsuitable for
the most demanding research and engineering applicationsnull
Page nullSPIRENT eBook
For more comprehensive testingnullSpirent also offers products that
simulate additional system elements simultaneously nullth the GNSS
constellation signalsnullsuch as inertial sensorsnullvarious automotive
sensorsnullnullsisted GPS (nullGPS) nullnullsisted GnullnullnullS (nullGnullnullnullS)
datanullSnullS and GnullS augmentation system signalsnullinterference
signalsnullGNSS nullecord nullPlaybacnulland nulli-Fi Positioningnull
Snullrent GSS8nullnull
Multi-GNSS nullnstellation
Simulator
Snullrent GSS67null
Multi-GNSS nullnstellation
system
Snullrent GSS63null
Multi-GNSS Signal
generator
Snullrent GSS64null
nullecord nullPlaybacnull
System
Snullrent GSS57null
nulli-Fi nullccess Point
simulator
Page nullSPIRENT eBook
We hope you found this Spirent Testing Multi-GNSS in an R&D
Environment E-Book of interest.
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