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Free eBook: GSS6400 RF RPS Application and Testing Examples

GSS6400 RPS Applications and Testing Examples cover

‘Live-sky’ testing of GNSS receivers is both expensive (as you need to go out on field trials) and flawed (as the same environmental conditions can never be replicated for repeated tests).

Now there’s a way you can capture the richness of the live-sky environment in a way that saves time and money, and can be used again and again.

Download a free eBook to discover the many ways you can use Spirent’s GSS6400 RF Record and Playback system to record real-world GNSS conditions for use in the lab. Example uses include:

• Chipset and product design

• Proving new algorithms for high-sensitivity receivers

• Production testing

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 25 years. Spirent delivers navigation and positioning test equipment and services to governmental agencies, major manufacturers, integrators, test facilities and space agencies worldwide.

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    GSS6400 RPS Applications and Testing Examples This document… … describes the applications, uses and results that can be obtained when using the GSS6400 signal Record and PlanullacnullSnulltem nullr the denullelopment and test onullGnullnullASS and GnullS receinullersnull Page 2SPIRENT eBook The GSS6400 Record and PlanullacnullSnulltem reduces nullour testing, trials and tranullel costs substantiallnullbnullallowing nullou to record real linull GnullnullASS or GPS signals nullncluding the real world nulldes, multipath and internullrencenullonto the internal hard drinulle onullthe unitnullnullnce nullou hanulle this data nullou can then repeatedlnullplanullit bacnullinto nullour snulltem under test in the comnullrt onullnullour own lab, without the need to return to the nullld, sanullng nullou time and monenullnull Figure 1 Spirent GSS6400 Page 3SPIRENT eBook Typical Applications include • Software and Hardware Testing • Repeatability Tests • Manufacturing Test • Performance analysis • System trials • A-GPS trials • nullnospnullric and interference monitoring • Algoritnull studies • Position • Multipatnull • Sensitinullty Page 4SPIRENT eBook Example uses for the GSS6nullnull Chipset and product design Tuning onullsonullware and algorithms to pronullde optimum pernullrmance in real world situations occupies a lot onulldenullelopment timenullnulln particular ennullronments the traditional approach has been to position denullelopment resources on site and conduct real time trials whilst denulleloping impronullements and solutions to problemsnullThis has the added dinullcultnullonullnot recreating the exact conditions on subsenullent tests, and renullired engineers to be awanullnullom mainstream denullelopment nullr extended periods onulltimenull Page 5SPIRENT eBook nullith the RPS snulltem the GnullS signal ennullronment can be recorded once, manulle at dinullnullrent times onulldanulland then used bacnullat nullasenull nullr subsenullent denullelopment and testingnullnullnulllocal personnel are anullailable nullr recording, then tranullel nullr denullelopment engineers is eliminated entirelnullnull Page 6SPIRENT eBook Prove new algorithms, especially nullr new high sensitivity receivers GnullS receinullers begin their testing and pernullrmance pronullng with simulator signals and long test campaignsnullnullonullng to the nullreal worldnull as experienced bnullend customers onullen renullires the algorithms to be nullld tested, using repeated runs in nullown ennullronments such as citnull areas and locations with high internullrence or obscurationnullnullnullholding a librarnullonullprenullecorded signals nullom such areas, much onullthis wornull can be achienulled without leanullng the bench, thus cutting both costs and denullelopment timenullnullanges to algorithms are easilnullpronullen using the same signals onuller and onuller, without the need nullr more nullld testingnull Page nullSPIRENT eBook Production testing Production testing usuallnullinnullolnulles the replanullonullthe same signal scenario nullr each test run, or using onullnullair signals nullr testingnullThe GSS6400 pronulldes a cost enullnullctinulle method onullpronullding repeatable GnullS signals under the control onulla test Pnull or nullom its nullont panelnull nullnce the test signal has been recorded nullrom a simulator or nullom linulle snullnull consistent replanullcan then be obtained, nulleeing up the simulator nullr other wornulland prenullenting linulle snull anomalies internullring with testingnull Page nullSPIRENT eBook Reducinnullnullield Trial nullsts and Position Repeatanulllity A Spirent GSS6null0 simulator was used to generate a scenario in nullnull nullnullG, using both GnullnullASS and GPSnullThe direct output nullom the simulator was nulld into a GPSnullnullnullASS receinuller and the positions determined and output into Google EarthnullThe same scenario was then recorded onto the GSS6400 and then subsenullentlnullplanulled bacnull Page nullSPIRENT eBook The nullllowing picture shows the tracnull onullthe positions as calculated directlnullnullom the simulator signal, and those planulled bacnullthrough the GSS6400nullThe green dots are direct nullom the simulator and the red anuller planullacnull Figure null nullerlanullonullcalculated positions direct nullom a simulator, and planulled bacnullnullom the GSS6400 Page nullSPIRENT eBook Figure null Positions nullom simulator, and replanulled nulloomed innull nullnullwe nulloom in nullrther we can see the results between the outputs direct nullom the simulator and those recorded and planulled bacnull on the GSS6400 are within a metrenull Page nullSPIRENT eBook Figure null nullultiple replanull nullom the GSS6400 This is the same test again but with nullplanullacnull nullom the GSS6400, compared with the direct simulator output nullreennull This shows that the signals planulled bacnullnullom the GSS6400 can be used to produce both AnullnullATE and REPEATAnullE positions nullom the stored GnullnullASSnull GPS signalsnull Page nullSPIRENT eBook nulle GSS6400 has several nullatures to manull the nullld recording simplenull • Single box with no need to attach a Pnullor external drinulle • null0Gnullinternal hard drinulle nullr null hours onullrecording • nullo unnecessarnullwires • An internal batternullthat lasts nullr nullhour while recording • Simple one touch recording null long press on the nullont panel Enter buttonnull see below • nullnull and nullont panel controls • nullornull with nullnullnullr power adapter, and no need to worrnullinullthis power source inadnullertentlnullnullils as the internal batternullwill seamlesslnull tanull onuller • nullrrnullcase and handle nullr walnullng trials Figure null nullront Panel Page nullSPIRENT eBook Alnullorithm TuninnullnullPosition Repeatanulllity nullBatch Testinnullnullnullnulluse nullen GnullS tests are undertanulln in dense urban cannullons there are nullwer obsernullations because onullthe obscuration onullthe satellitesnullThis leads to the solution onlnullnullst hanullng enough satellites to be able to manull a position determination, and the accuracnullis degradednull Tnullicallnullin dense urban areas to obtain a position null at all nullou hanulle to relnullon multipathed signals reaching the antenna nulla senulleral bounces onullnullbuildingsnullnullith onlnulla nullw satellites in nullew it is possible that the solution appears tens onullmetres onullnullthe true routenull Page nullSPIRENT eBook The GnullS receinuller also has to wornullnullernullhard to renullcnullire the satellites as it monulles in and out onullareas onullsatellite nullsibilitnullnull The sonullware will be searching in the time and nullenullencnulldomains in order to renullcnullire a lost satellite, or nulld new ones, and will be increasing its integration steps to allow it to acnullire satellites at nullernulllow signal lenullelsnullSnulltem designers and sonullware engineers therenullre spend a lot onulltime tuning the nullters and rerunning test anuller testnull nullnce recorded, the GSS6400 replanull exactlnullthe same signal each timenullGnullS snulltem manunullcturers can therenullre use the GSS6400 to replanull, time and time again, the Rnullsignals stored during the initial trialnullnullt allows the denullelopers to impronulle their tracnullng and nanullgation sonullware so that the enullnullcts onullmultipath, internullrence and nullding signals are minimisednull Page nullSPIRENT eBook null nullor example nullters manullhanulle to be tuned and acnullisition strategies determined to get the best possible null while the unit under test is being drinullen round a roundabout, while at the same time losing locnullon the satellites and renullcnulliring the signals as it goes under the nullnullnullersnull So instead onullhanullng to do the test in the nullld on mannullan occasion, the GSS6400 can record then data once and then it can be planulled bacnullmultiple timesnull Page nullSPIRENT eBook null nulln the nullllowing picture the nullehicle dronulle round the roundabout two times nullhe white linesnullbut then the same signals were recorded and subsenullentlnullplanulled bacnullnullom the GSS6400 a total onullsix timesnull Figure null Algorithm tuning Page nullSPIRENT eBook null nullor use in the nullnullthe GSS6400 has some nullnenullial nullaturesnull null nulln be controlled bnullthe nullont panel null nullou can attach a Screen and nullenulloard and use the inbuilt nullebsernuller, which ginulles nullou nullll control onuller the snulltemnull Figure null nullebsernuller Page nullSPIRENT eBook null null The signals can also be attenuated to see the enullnullct that has on algorithms under test, bnullup to nulldnullin nulldnullstepsnull null nullata can be archinulled onto external SATA drinulles using the nullst data transnullr nullnctions onullSATA nullnullnullnullnull null nullata nulles recoded on one snulltem can be planulled bacnullon another unitnull nulle GSS6400 also allows you to automate your test process asnull null Scripts can be written to automaticallnullplanullbacnullginullen nulles in a ginullen order null nulle controlled locallnullor remotelnullnulla the web to maximise the use onullthe snulltem null nullou can nullnullinto the snulltem nullr additional nullxibilitnull Page nullSPIRENT eBook null nullonullGSS6nullnullnullrksnull The GSS6400 RPS emplonull a low noise amplinullr nullr optimum onullerall snulltem noise pernullrmance prior to downnullonnullerting to null nullr digitisingnull An AGnullcircuit caters nullr a wide range onullactinulle or passinulle antenna gainsnullStandard antennas with gains onullup to nulldnulland nullnullnullnominal null power can be used directlnullnull The digitised null is stored on an internal null0null hard drinulle ginullng up to nullhrs onullrecord timenullAlong with the data nulle containing the digitised signals, an accompannullng innullrmation nulle is automaticallnullgenerated containing details such as record time and datenullnullurther data can be added to this nulle nullr record nulleping purposesnull Page 20SPIRENT eBook nullata nulles can be stored using two bit nullign and magnitudenullor one bit nullign onlnull nullantisation, depending upon the renullirementsnull nulln planullacnullthe null signal is recreated and then upnullonnullerted to Rnull at the GPS null nullenullencnullonullnullnullnullnullnull, and the GnullnullASS centre nullenullencnullonullnull0nullnullnull using a built in onullen stabilised local oscillator nullnullnull nullr minimum phase noisenull A common nullnullnullnullTnullnullis used as the clocnullnullr GPSnullnullnullASS denullces to nullep nullnullsamples in phase with each othernull The nullnullis sampled at nullnullnullnullr GPS with a nullter bandwidth onullnullnullnull, and at nullnullnullnullr GnullnullASS with a nullter bandwidth onullnullnullnull Page 2nullSPIRENT eBook Carrier to nulloise pernullrmance The GSS6400 nullithnullllnullrecords and planull bacnullthe Rnullsignals obsernulled during a trial to within a nullw dnull onullthe nullalue obsernulled directlnullin the nullldnullTnullicallnullnullr nullbit GPS or GnullnullASS recording the dinullnullrence is nullst nullnull while at nullbit it is nullnull The recording includes all the realnullinull nulldes, multipath and internullrence as seen in the realnullorldnull As we hanulle seen inullnullou compare the position output onullthe GPSnull GnullnullASS receinuller used in real time and the output nullom the GSS6400 with the same receinuller the positions will match almost exactlnullnull Page 22SPIRENT eBook nulle can do a similar analnullis bnullloonullng at the nullrrier to nulloise ratios onulla recorded, and then planulled bacnullset onulldatanullnulln this test we are recording nullbit GPS signals onuller a period onullnull minutesnull nullnullwe calculate the AnullRAGE nullnullo nullom the Real time and the Planulled bacnullonuller the null minute period we hanullenull nulln this null minute test the anullerage planulled bacnullnullrrier to nulloise Ratio is 0nullnulldb below that onullthe real time signalnull Figure null nullrrier to nulloise comparison Real nullime nullverage Cnullo nullnull Played nullacnullnullverage Cnullo nullnull 44nullnull 44null6 Page 23SPIRENT eBook nullNnullnullInull Tnull GSSnullnull record and playbacnullsystem can greatly reduce tnull cost of nullld trialsnulland tnull time tanulln to denulllop new algoritnullsnull by bringing tnull complenullties of nulleal-worldnullGnullS signals bacnullinto tnull ofnullenull Tnull GSSnullnull is nullgnully portable and self containednullallowing easy recording in tnull nullldnullnullen used in tnull ofnulle nullwenullr it is transformed into an nullgnully efnullient piece of laboratory enullipment allowing GnullS signals to be replayed witnullaccuracy and repeatabilitynull null is nullry nullnullblenullallowing automated operation for testingnulland can be controlled remotelynull Page 24SPIRENT eBook nullnullnullou nullund this enullonullonullinterest we thinnullnullounullll also be interested in downloading nullnull introduction to GnullS Record null PlaynullcnullSystem Pt 2 null nulle are continuallnulladding new content to our website on a regular basisnullnullonullarnullthis linnull wwwnullpirentnullomnullositioning nullisit the Spirent GnullS nulllog, there are currentlnull more than null posts with nullto nullnew posts added per weenull nulltch up on whatnulls newnull wwwnullpirentnullomnulllognullositioning nulleed more innullrmationnull gnssnullolutionsnullpirentnullom Sharenull nullaceboonull nullnnulldnulln Twitter Technorati Google nullunull nulligg nullelicious Reddit Stumbleupon Renullnullnull0 nullul nullnull nullntact null Spirent null4 null0nullnull6nullnull globalsalesnullpirentnullom wwwnullpirentnullomnullositioning Spirent nullederal Systems null null4 6null 6nullnull innullnullpirentnullderalnullom wwwnullpirentnullderalnullom Got a smartphonenull Scan tnull null nullde for more information