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Application Note: Simulation of Realistic Antenna Noise

Simulation of Realistic Antenna Noise

During RF simulation, it is important to compensate for receiver and environmental noise temperatures – failure to do so can result in some surprising measurements.

Download the Application Note to learn how you can calibrate your simulator to model realistic antenna noise levels. Topics include:

  • Adjusting simulator levels to compensate for unexpected noise temperatures
  • Simple and complex antenna noise models
  • Modelling constantly changing noise temperatures—a worked example

Simply enter a few details opposite to receive the Application Note—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.

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    Simulation Of Realistic Antenna Noise APPLICATION NOTE Spirent Communications PLC Paignton, Devon, TQ4 7QR, England Web: nulltp:nullnullnullnullpirentnullomnullositioning Tel: null4 nullnull nullnullnull nullanull null4 nullnull nullnullnull Copnullignull nullnullnull Spirentnull nulll Rignulls Reservednull nulll onulltnull compannullnames andnullr brand names andnullr product names renullrred to in tnulls document, in particular, tnull name nullpirentnulland its logo device, are eitnullr registered trademarnull or trademarnull onull Spirent plc and its subsidiaries, pending registration in accordance nulltnullrelevant national lanullnullnulll otnullr registered trademarnull or trademarnull are tnull propertnull onulltnullir respective onullersnull Tnull innullrmation contained in tnulls document is subnullct to cnullnge nulltnullut notice and does not represent a commitment on tnull part onullSpirentnull Tnull innullrmation in tnulls document is believed to be accurate and reliablenull null ever, Spirent assumes no responsibilitnull or liabilitnullnullr annullerrors or inaccuracies tnullt manullappear in tnull documentnull Page 2SPIRENT Application Note Contents Scope 4 nullntroduction 4 nulloise nullodels null Simple nulltenna nulloise nullodel null nullore Complenullnulloise Environment, nullgnoring Simulator nulloise 7 nullore Complenullnulloise Environment, Removing Simulator nulloise null nulltenna Directivitnulland Satellite Signals null nullsing tnull Simulator nullonnullal Port null SimPRnullESS nullodel null Wornulld enullmple: Static nullnullSpacecranull null nullsing a Spirent nullSS Simulator to Test nullnteroperabilitnulland Compatibilitnullnullssues null Signal Content Control null Timing Control null nullavigation Data nullodinullation null nullsessing tnull True nullenenull null Testing tnull limits onulltnull cnullp null nulle Sensitive to tnull Environment null null classic receiver test, but nullst as critical nullr a nullultinullnullS receiver null nullamming and nullnternullrence null Test tnull enullnullcts null Tnull snullnulls tnull limit null Test Solutions null nullSnullnull nullultinullnullS Constellation Simulator null nullSnullnull nullultinullnullS Constellation Simulator null nullSnullnull nullultinullnullS Constellation Simulator null nullSnullnull Record nullPlanullacnullSnulltem null Page 3SPIRENT Application Note Scope Tnulls nullpplication nullote gives guidance on tnull simulation onullmore realistic antenna noise levels nulltnullSpirent nullSS simulators bnullmanipulating signal levels based on nullonulledge onullreceiver and environmental noise temperaturesnull Introduction Spirent Communicationsnull nullSS simulators allonulla user to specinull received signal ponuller level nulltnullnullgnullaccuracnullnullnullonullever it is not unusual nullr nenullusers to be surprised at tnullir receivernulls signalnullonull noise nullnullnullor carriernullonulloise nullnullnull measurements, even tnullugnulltnullnullnullve matcnulldnullp tnull simulator signal levels and antenna level patterns nulltnullestimated realnullorld valuesnullTnull problem gets nullrse inulltnull simulatornulls nullgnulllevel nullonnullal port is used to connect to tnull receiver via a carenullllnullcalibrated Rnullattenuatornull Tnull enulllanation is usuallnullnoise levelnull nulln all Spirent simulator designs tnullre is sunullcient passive attenuation betnulleen active electronics to Rnulloutput tnullt tnull output noise temperature is denulled bnull tnull temperature onulltnull output attenuator, nullicnullis around tnull room temperature onulltnull laboratornullnullnull tnullical realnullorld antenna pointing at tnull snull nullll nullve a noise temperature less tnulln tnullsnull Wnull doesnnull tnull simulator sonullnullre, enullnullSimnullnull, tanull tnulls enullnullct into account and nullst cnullnge tnull renullested ponuller levels to compensatenullnullnnullrtunatelnulltnull necessarnulllevel cnullnge depends upon tnull environmental and receiver cnullracteristics tnullt normallnullare unnullonull to Simnullnullnull Tnulls note gives a brienulldescription onullnullnull a user can nullrnullout nullnullto cnullnge simulator levels to compensate nullr tnullse enullnullctsnullnullt also enulllains nullnullto use tnull SimPRnullESS tool in order to seminull automate tnullse enullnullcts, including nullr dnullamic spacecranull nullere antenna noise temperature can be constantlnullcnullngingnull Page 4SPIRENT Application Note Noise Models null number onullmodels nullll be considered nulltnullincreasing complenulltnulland realismnull nulln some cases at least, tnull user can nullst calculate a nulled level onullnullet to applnullin tnull scenarionulls signal source nullenull Simple Antenna Noise Model nulll models renullire tnull user to nullonull tnull enullivalent input noise temperature onulltnull receiver togetnullr nulltnullestimates onullenvironmental noise temperaturesnull Suggested denullults nullr tnull later are givennull nullnulltnull antenna noise temperature is a nulled nullonull value, tnulln a nulled level onullnullet can be nullund as nullllonullnull nullor nullWnull tnull total ponuller can be enullressed as W nullere nullis nullltnullannnulls constant, nullnullnull4Enullnull T is tnull absolute temperature, null nulltnull snulltem noise bandnulldtnull nullnull nullnulltnull Snull measured bnulltnull receiver is to be tnull same betnulleen real nullrld and simulator tnulln nullere s is tnull realnullorld antenna signal ponuller to be simulated na is tnull realnullorld antenna noise to be simulated nr is tnull receiver enullivalent input noise ponuller snull is tnull simulator output ponuller modinulld to give tnull correct receiver Snull nsim is tnull noise ponuller on tnull nullal output onulltnull simulator Tnulls inullRn is tnull dnullcnullnge in simulator output to give tnull correct receiver Snull, tnulln Page nullSPIRENT Application Note nullt is also nullrtnullmentioning tnullt tnull term nullultinullnullS manullalso be applied to additional signals nulltnulln tnull same snulltem in so nullr as tnullnullcontribute to an improvement in navigation pernullrmancenull nullor enullmple, most civilian users onullnullS, nullve relied on tnull single Cnullnullode signal on Lnull Soon, tnullnullnullll nullve access to Lnull, Lnull, nullicnullonullciallnullsupports civilian dualnullrenullencnullreceivers, and Lnull nullicnullis a robust signal allonullng ennullnced atmospnullric error mitigation, certainlnullmore tnulln is possible nulltnull a singlenullrenullencnullreceivernull nullinallnull, nulle must not nullrget augmentation snulltemsnullTnull Wide nullea nullugmentation Snulltem nullWnullSnullnulls instigated bnulltnull null nullederal nullviation nulldministration to improve tnull accuracnullonullnullS so tnullt aircranull could relnullon it more nullr all pnullses onullnullgnullnull Tnull nullnternational Civil nullviation nullrganinulltion nullCnullnull calls tnulls tnulle onullsnulltem a Satellite nullased nullugmentation Snulltem nullnullSnull Europe and nullia are developing tnullir onull SnullSs, tnull European nulleostationarnull nullavigation nullerlanullService nullnullnullnullnullicnull nullll be operational bnullnullctober nullnull, and tnull nullapanese nullultinullunctional Satellite nullugmentation Snulltem nullSnullnull nulll tnullee are designed to tnull same specinullation nullTCnullDnullnullnullnulland are nullllnull interoperablenull nulltnullr regional snulltems include tnull QuasinullenitnullSatellite Snulltem nullnullSnullin tnull Pacinull region, tnull nullndian nullS nullded nulleo nullugmented nullavigation nullnullnullnull and tnull nullndian Regional nullavigation Satellite Snulltem nullRnullSnull Commercial snulltems include Starnullire and nullmniSTnullnull nullroundnullased localised snulltems also enullst, sucnullas tnull Local nullea nullugmentation Snulltem nullnullSnullnullr siding aircranull navigation on nullal approacnulland landing, and DinullnullrentialnullPS snulltems based on netnullrnull onullground monitoring stationsnull nullnertial nullavigation Snulltems nullnullnullalso planull an important part in tnull augmentation onull nullSS, and are alreadnullnulldelnullemplonulled in airborne and automotive applicationsnull nullsistednullnullS is also a critical nullature in improving time to null and accuracnull, particularlnullin tnull use onullnullSS in mobile pnullne snulltems nullere navigational assistance data valid nullr a mobile nullndsetnulls specinull location is sent to tnull nullndset via tnull bacnullaul telepnullne netnullrnullin advance onulldenullodulation onullsucnulldata nullom tnull nullSS satellites bnulltnull nullndsetnulls onnulloard nullSS cnullpnulletnullTnull discussion onullnullS and nullnullSS is nullnullever outside tnull scope onulltnulls paper, nullicnullconcentrates on nullultinullnullS in relation to standnulllone receiver pernullrmance improvementnull nulliving: dnull nullnull Point onullinterest: absolute or tnullrmodnullamic temperature is measured in nulllvin, nulland not tnull degreenullelvin, nullnullSee nulltp:nullennullinullpedianullrgnullinullnullelvin nullr nullrtnullr readingnull Page nullSPIRENT Application Note More ComplenullNoise EnnullronmentnullIgnoring Simulator Noise Tnullicallnullan antenna nullll be subnullct to noise nullom more tnulln one source so tnull resulting antenna noise temperature nullll depend upon tnull antenna gain pattern and venullcle orientationnullnulln tnulls model tnull sources are considered, eartnulland snullnull Simulator output noise is considered to enullate nulltnullsnull noise but a later model does not do tnullsnull nullsume tnull simulator output noise enullates nulltnullspace noisenullTnull antenna noise temperature can be nullund nullom adding up tnull nullactional contributions onulleacnull antenna pattern element, tanullng account onullits gain and nulletnullr it is pointing at tnull eartnullor tnull snullnull nullirst inulltnull antenna level pattern nullom Simnullnull is to be used in a noise calculation, tnull dnullloss value onulleacnull element must nullst be converted to linear units and tnull enullnullct onulldirectivitnull is includednullnullnullnull is tnull loss in dnullonulltnull itnull element given in tnull antenna pattern nulle, range nullto 4nulldnull tnulln ai nullnullnullinullnull nullt can be snullnull tnullt tnull directivitnull d onullan antenna is given bnull summing over tnull nullole antenna, nullere Ωi is tnull solid angle made bnulltnull itnullelementnull Tnulln nullonulltnull antenna noise temperature is nullund bnullsumming tnull noise temperature contribution onulleacnullelements: nullere Σ snull indicates summation over all tnull snullnullointing elements and Σ eartnullsummation over all tnull eartnullpointing elementsnull nullnullsimulator noise is to be enullated nulltnullsnull noise, tnulln nullom enullation Enull Enull dnull nullnull Page null SPIRENT Application Note Enullmple nulloise temperatures are estimated to be nulled as nullllonull: receiver: nullnullnull eartnull nullnull snull: null Let tnull antenna pattern be an ideal nullmispnullre nulltnullnulldnullloss nullr one nulllnull and innullite loss otnullrnullsenullTnulls tnull gain, gi is nullaround boresignull and nullotnullrnullsenull Let tnull antenna boresignull be pointing at tnull nullrinullon so nulllnulltnull nulldnullelements are snull pointing, tnull otnullr nulllnulleartnullpointingnull Tnull summation can be simplinulld and tnull antenna manullbe considered in nullur enullal nullarters, depending upon gain and source noise temperaturenullSo tnull antenna noise temperature is given bnull Ta nullnullnullTs nullnull null nullnull nullnullTs nullnull null nullnullTe nullnull nullnullnullTe nullnull nullnullnullnull Tnulln Rn nullnull nulllognullnull nullnullnull nullnullnull null nullnullnullnullnullnull dnull So tnull ponuller level is reduced bnullnullnulldnullto simulate tnull enullnullct onulleartnullnoise tnullt is considered nullgnullr tnulln simulator output noise, in tnulls modelnull Page nullSPIRENT Application Note More ComplenullNoise EnnullronmentnullRemonullng Simulator Noise Tnulls is acnulleved bnullsimplnullusing Enullto calculate Ta and using Enullto nulld Rnnull Enullmple nulloise temperatures are estimated to be nulled as nullllonull: receiver: nullnullnull simulator: nullnull eartnull nullnull snull: null Same nullmispnullrical antenna pattern as tnull previous enullmplenull So Ta nullnullnullnulland tnulln Rn nullnull nulllognull nullnull nullnullnull nullnullnull nullnullnull nullnullnullnull dnull So nullre tnull ponuller level is increased bnull null7 dnullto remove tnull simulator noise enullnullct tnullt is larger tnulln tnull antenna noisenull Antenna nullirectinulltnulland Satellite Signals Tnull convention in Simnullnull is nullr an antennanulls gain pattern to be represented bnull denulling a base signal level corresponding nulltnulltnull direction onullgreatest gainnullTnull gains onullotnullr elements are represented bnulla loss pattern, nulltnullrange nullto 4nulldnull nullonulldoes a user nulltnullan antenna gain pattern proceednull anull Convert tnull dnullgain pattern elements to normalised loss: Li null nulli null manullnull dnull nullere: nulli is tnull gain onulltnull itnullelement manullnull is tnull largest gain in tnull pattern Li is tnull loss value nullr tnull Simnullnull antenna pattern bnullnullnullnullet tnull satellite signal global level onullnullet bnullRs, nullere Page nullSPIRENT Application Note nullsing tnull Simulator Monnullal Port Tnull considerations discussed above applnull enullallnullinullusing tnull nullgnulllevel rear panel nullonnullal portnullnullonullever tnull user must tanull care in estimating Tr, tnull receivernulls enullivalent input noisenull Tnull output noise nullom tnull nullonnullal port and enullernal attenuator is still about tnull same as tnull nullont panel output port but tnull receiver is missing tnull noise normallnulladded into tnull signal patnullbnull tnull prenullmplinullrnull SimPROCESS Model SimPRnullESS is a compiled nullTLnull application supplied nullee to users onull Simnullnull nulltnullmaintenance contracts or nullrrantiesnullSimPRnullESS nullll snullrtlnullnullve an antenna model addednull Tnulls nullll calculate antenna directivitnulland eartnullsnull noise temperature contributions and optionallnullgive a level onullnullet value to tnull user or generate a command nulle tnullt nullll be used bnullSimnullnull during a scenarionullTnull later is usenulll nullr spacecranull undergoing attitude cnullnges during a Page nullSPIRENT Application Note nullornulld enullmplenullStatic nullO Spacecraft Consider a spacecranull in geostationarnullorbit nulltnullno translational or angular motion in tnull ECEnullnullamenull null single antenna nulls its boresignull enullctlnull eartnullpointing and nulls a nullmispnullrical gain patternnullnulln Simnullnull tnulls is simulated nulltnull an antenna pattern nullicnullnulls nullnullloss nullr elevations nullnulland 4nulldnullloss otnullrnullsenull Tnull receiver enullivalent input noise temperature, Tr, is nullonull to be nullnullnull nulltnullr constants to be used are: nullirst nulld tnull antenna noise temperature, Ta Directivitnull, d null4 nullpi nullnullnullnullnullnullnull nullnullnullpi nullnullnullnull 4nullnullnullnullnullnullpinull nullnullnullnull4null nulltenna elements nulltnullcentres considered to be eartnullpointing nullll nullve an angle onullnull tnull boresignull given bnull tnullta nullatannullRe nullRgeonull nullnullnullnull Space noise temperature, Ts nullnull null Eartnullnoise temperature, Te nullnullnullnull Simulator output noise temperature, Tsim nullnullnullnull nullnullC output attenuator temperaturenull Eartnullnulls radius, Re nullnull7nullnull m nullnullseminullanullr anulls Rgeo null4nullnullnull4 m ⁴ nulln terms onulla Simnullnull antenna pattern, boresignull is tnull direction onullelevation nullnullnull Page nullSPIRENT Application Note Ta null nullnull null Tnulls result manullbe applied in a number onullnullnullnull Case null Tnull simulator output noise can be enullated nulltnullspace noise and tnull additional noise nullom tnull eartnullis simulated as a reduction in signal ponuller: Rn nullnull nulllognullnullTs nullTrnullnullnullTa nullTrnullnull nullnullnullnulldnull Tnulls cnullnge is less tnulln tnull simulator ponuller resolution onullnullnulldnulland can be neglectednull Case 2 nullnclude tnull enullnullct onullsimulator output noise: Rn nullnull nulllognullnullTsim nullTrnullnullnullTa nullTrnullnull nullnullnullnull dnull Tnulls in tnull Simnullnull Signal Sources nulle tnull global onullnullet ponuller snulluld be increased bnullnull7 dnullover tnullt nullr a nullmispnullrical antenna on tnull eartnullnulls surnullcenullnullnulltnull enullsting ponuller level represents tnullt nullr an isotropic antenna, an additional nulldnull snulluld be added manullng a total onull4nulldnull Page nullSPIRENT Application Note nullsing a Spirent nullSS Simulator to Test Interoperanulllitnulland CompatinulllitnullIssues Spirentnulls nullSnullnull , nullSnullnull and nullSnullnull series onullnullSS Rnullconstellation Simulators are essential tools nullr testing a nullSS devicenulls abilitnullto cope nulltnullinteroperabilitnull issuesnullnullot onlnullare tnull proven advantages onullRnullemulation over otnullr metnullds onull testing applicable, but more nullndamentallnull, tnull present absence onullsignals in space nullr all nenullnullSS snulltems enullcept nullr nullS and nullnullnullS nullDnullnullmanull tnulls approacnull impossible in annullcasenullnulln some nullnull tnulls is good, as it ensures proper test metnullds are emplonulled, and saves time tnullt manull otnullrnullse be spent gatnullring meaningless results using tnull instantaneouslnullunnullonull and unnullontrollable nullivenull signalsnull Eacnullonulltnull individual nullSS snulltems nulltnulltnullir appropriate constellation, orbits, signals, timing and navigation data are produced bnulltnull simulator in accordance nulltnulltnull relevant nullnternullce Control Document nullCDnulland combined to present a signal to tnull receivernullndernull testnulls antenna, nullst as it nulluld see nullr realnullPracticallnullannullparameter can be manipulated, allonullng signals and data messages to be cnullnged, internullnulltem timing to be adnullsted and transnullrmation matrices betnulleen renullrence nullames to be adnullstednull nullull nullnullbilitnulland control onulltest denullition and enullecution is anullnullrded bnullSpirentnulls Simnullnull sonullnullre, nullicnullcontrols tnull nullSnullnull and nullSnullnull series simulatorsnull Some enullmples onulltnull capabilities Simnullnull nulls nullr creating scenarios to test nullSS interoperabilitnullissues are snullnull belonullnullTnull nullll complenulltnullonullscenarios is also carried donull in an embedded nullnullto Spirentnulls SimREPLnullnull sonullnullre, nullicnullruns tnull nullSnullnull simulatorsnull Page nullSPIRENT Application Note Signal Content Control Simnullnull allonull tnull user to control signal content parameters nullr eacnull simulated nullSSnullnulligure nullsnullnull tnull Signal Control nullndonull onullSimnullnull or nullnullnullS and nullalileonull Signal parameters can be adnullsted on a pernullatellite basis, andnullr applied to all satellitesnullTnulls nullnullbilitnullenables tnull user to test receivers nulltnulldinullnullrent carrier, code and data combinations, and to assess possible signal internullrence issuesnull nullnullRE null SnullnullL CnullTRnull WnullDnullWS Page nullSPIRENT Application Note Timing Control Simnullnull gives nullll control onullinternullnulltem timing onullnulletsnullnulligure 7 snullnull botnulltnull nullalileo and nullnullnullS snulltem time settingsnull nullt is possible to set tnull time onullnullet to nullC nulleap secondsnull and applnulla rate onullcnullnge to tnulls as tnull scenario runsnull nullor nullalileo, tnull time onullnullet to nullS nulleclared in tnull nullTnullmessage in tnull navigation datanullcan be set, as nullell as a divergence betnulleen tnull simulated nullnull signal timing and tnullt declared in tnull navigation datanull null nullppens nulltnulla real snulltem as time advances anuller a navigation data uploadnull Tnullse nullatures provide great nullnullbilitnull in denulling tests to ensure receivers are correctlnullapplnullng tnull necessarnull onullnullets and timing, nullicnullare critical to accurate navigationnull nulligure nullsnullnull tnull options available nullr setting dinullnullrent matrices to transnullrm tnull nullnullnullS renullrence nullame into tnull nullS Wnullnull4 nullamenullDinullnullrent transnullrm tnulles are available, as nullell as tnull abilitnullto adnullst tnull individual matrinullparameters via a nulleneric nullelmert transnullrmationnull Tnull nullalileo renullrence nullame is treated tnull same as nullS bnulltnull simulator, as tnullnull botnullalign vernullcloselnullto eacnullotnullrnull nullnullRE 7: SnullTEnullTnullE nullnullET WnullDnullWS Page nullSPIRENT Application Note Nanullgation nullata Modinullation null important capabilitnullnullr tnull simulator is tnull abilitnullto modinull and applnullerrors to tnull navigation messages onulleacnullnullSSnull Simnullnull nulls comprenullnsive editors allonullng manipulation onullannullbit onulltnull navigation message, as nullell as adnullstment onullspecinull messages and tnullir scnullduling, and tnull control onullintegritnull and nullaltnullmessagesnull nullt is also possible to simulate tnull enullnullcts onulltnull age onulltnull navigation data, sucnull as diverging epnullmeris and degradation onullclocnullcorrection parametersnullnulligure null snullnull a tnullical editor used nullr modinulling navigation datanullnulligure null snullnull a tnullical editor nullr applnullng errors to navigation data nullnullRE null nullnullnullTnullnullDnullTnull nullDnullnullnullTnullnullEDnullnull nullnullRE null: nullnullnullTnullnullDnullTnull ERRnull EDnullnull Page nullSPIRENT Application Note nulligure null snullnull tnull entrnullpage nullr denulling tnull content and timing onull navigation data uploads, nullicnullis anotnullr metnulld nullr scnullduling cnullnges to tnull navigation messagenull nullnullRE null: nullnullnullTnullnullDnullTnull nullLnullnull CnullTEnull Page nullSPIRENT Application Note Otnullr considerations for MultinullNSS Testing Assessing tnull True nullenenull null nulle discussed earlier, tnull nullndamental renullirements onullannullnavigation snulltem nullve not cnullnged nulltnulltnull arrival onull tnull nullultinullnullS age, in nullct tnull added complenulltnullonullnullultinullnullS being used simultaneouslnullincreases tnull amount onulltesting renullired, particularlnullnullen it comes to assessing tnull improvement nullr otnullrnullsenullonulladding additional signalsnull Spot tnull difference null Rnullconstellation simulator is tnull pernullct tool nullr pernullrming comparative testsnullComplete repeatabilitnullis a ponullernulll nullature tnullt onlnulla simulator can onullnullrnullnullt is possible to run and renullun tests nulltnullone nullSS, tnulln add anotnullr, and anotnullr, and measure tnull cnullnge in pernullrmance, nullile nulleping all otnullr test parameters tnull samenull nullt is also vernulleasnullto add or remove signals nullom a particular nullSS, tnulls can even be done in realnullimenullnulligure null snullnull tnull ponuller control nullndonullnullr a simulation containing nullalileo, nullnullnullS and nullS signalsnullnull can be seen, tnull nullnullnullS signals nullve been turned onullnullnull Tnulls is acnulleved in nullst tnull mouse clicnullnull nulln tnull same nullnull, all satellites nullr anotnullr nullSS could be disabled or enabled, and individual satellites could be enabled or disablednullPonuller level control in nullnullnullsteps per cnullnnel is also vernulleasnullto applnullnull Tnullre are also several alternative metnullds available, sucnullas prenullcripted commands to be actioned at specinull times into a scenarionullTnulls nullite control is ecnulled tnullougnullut Simnullnull, manullng it enullremelnull ponullernulll and controllablenull Page nullSPIRENT Application Note nulligure null snullnull an alternative metnulldnull null single command is listed in tnull nullser nullctions nulle to turn on all nullnullnullS signals at a prenulletermined timenull Page nullSPIRENT Application Note Developing receivers tnullt integrate nullultinull nullSS tecnullolognullis not a nenullconceptnull nullS nullnullnullnullS receivers nullr enullmple nullve been readilnullavailable nullr over ten nullearsnull nullor tnulls reason mannullonulltnull cnullllenges are nullell understood, and tnullre are mannull papers discussing tnullmnull Wnullt is nenullis tnull transition onullnullultinullnullS designs nullom nullignullendnull receiver platnullrms into cnullpsets suitable nullr tnull massnullarnulltnull Tnull common constraints onullcost, sinulle, ponuller consumption and processing ponuller all planulltnullir part in raising tnull bar nullen it comes to acnulleving tnull desired resultnull Certain tradenullnullnull nullll inevitablnullnullve to be made, most linulllnullin tnull resources devoted to tracnullng and integrated processing onull nullultinullnullS signalsnull Wnullle enullensive receivers sucnullas tnullse used nullr geodesnullapplications nullll be sopnullsticated enougnullto emplonull codenullnullse or RTnulltnulle tecnullinulles using best multinullarrier nullbiguitnull resolution algoritnulls, and true multinull nullenullencnulltracnullng, not all devices can anullnullrd be tnulls capablenullRnullpernullrmance is onullen compromised because nullultinullnullS capabilitnullis needed but nulltnullincrease in overall cost pronullbitednull null common problem, especiallnullin nullSSnull enabled pnullnes, is use onullone common clocnulloscillator nullTCnullnull nullr botnulltnull telecommunications operation and tnull nullSS operationnullTnulls is not an ideal solution bnullannullmeans, as variations to tnull TCnullnullnullenullencnullare undesired nullom tnull nullSS receivernulls point onullvienullnull nullnnullrtunatelnull, tnull oscillators are onullen tnull most enullensive single items in tnull design, and economics onullen nullrces designers donull tnull nulltenulll singlenulllocnullroutenullTnullnulltnulln nullve to spend time developing tecnullinulles tnullt advise tnull nullSS receiver onullclocnull cnullnges in sunullcient time nullr tnullm to be corrected nullr in tnull Pnull calculationnull nulln addition, a vernullclose nulltcnullon pnullse noise is renullired, as tnulls directlnullanullnullcts code and carrier loop tracnullng pernullrmance bnullinducing nulltternullTnull nullalitnullonulltnull TnullCnullnullll also determine its sensitivitnullto dnullamic stress nullnullensitivitnull, nullicnullis nullet anotnullr contributor to tracnullng errornull nullucnullonulltnull pernullrmance analnullis and manipulating onulla design to accommodate tnullse design tradenullnullnull can be tnullrougnullnull enullmined using a simulatornull ³ nullSS on tnull null: Sensitivitnulland pernullrmance in receiver designnullLomer, nullulga nullnullammel SnullE, nullnside nullSS article, spring nullnull Page 2nullSPIRENT Application Note Testing tnull limits of tnull cnullp Witnullan Rnullconstellation simulator it is possible to stimulate a receiver nulltnull a nullullnull snull onullnullSS signals nullsometnullng not possible in tnull nullrealnull nullrld todanullnull Tnulls nullll pusnulltnull tracnullng and processing capabilitnullonulltnull cnullpnullet to its limitsnull nullt is even possible, tnullougnullmanipulation onulltnull satellite positions or tnull venullcle nullignull nulltnulln tnull simulator to place more satellites in vienullonulltnull receiver antenna tnulln manullever be seen nullr real nulltnulls testing tnull tnulloretical pernullrmance onulltnull receivernullnullccurate design denullating nullures can tnulln be obtainednull nulligure null snullnull a cronullded Simnullnull snull plotnullTnull simulator nullll be generating complete signals nullometimes nulltnullseveral dinullnullrent codesnullnullr eacnullsatellite, manullng a complenullcomposite signal nullr a receiver to denullodulate and processnull Tnull simulator is able to introduce tnull enullnullcts onulldnullamic stressnullTnulls nullll be absent nullom a receiver being tested on a simulator because it is not moving pnullsicallnullnull Tnull nullonull nullsensitivitnullonulltnull receivernulls clocnulloscillator can be added to tnull test scenario to compensate nullr tnullsnullnulligure null snullnull tnull entrnull nullndonullin Simnullnullnull null combination onullenullnullcts can be built into a scenario, and detailed measurement onullCnullo pernullrmance can tnulln be madenull Errors can tnulln be vernulleasilnullremoved, one at a time, to identinull tnull main causes onullpernullrmance deteriorationnullnullocus can tnulln be put on areas onulltnull design nullere cnullnges nullll nullve tnull most benenullnull nullnullRE null: nullSEnullnullnullnullnull PnullnullETERS Page 2nullSPIRENT Application Note nulle Sensitinulle to tnull Ennullronment nullood sensitivitnullis still tnull most important consideration nullr annullreceivernullWitnullnullultinull nullSS, tnullre nullll be more signals entering a receivernulls nullont endnullTnulls nullll lead to an increase in noise, nullicnullnullll anullnullct tnull receiver bnullincreasing tnull bit error rate and code nullcarrier loop nulltternull nullso, in devices sucnullas mobile pnullnes, tnull dominant source onullinternullrence nullll be nullom tnull telecommunications radio part onulltnull devicenullnull tnullical nullndset nullll transmit over a nulltt nullnullnullnullnullin tnull designated band, but due to tnull nullrm onulltnull device, internullrence nullom tnull telecommunications radio signals can easilnull internullre in tnull nullSS band and overponuller tnull relativelnullnulleanullnullSS signals, directlnull impacting tnull nullSS receivernulls sensitivitnullnull nullood Rnullisolation is essentialnull nullotnullr consideration is tnullt onull tnull Lonullnulloise nullplinullr nullnullnull Due to cost constraints it is most common nullr a device to use one Lnull to cover botnulltnull telecommunications signals and nullSS signalsnullTnull large dnullamic range in ponuller betnulleen tnull tnull services means tnull Lnull must be vernulllinear, nullilst not consuming too mucnullsupplnullcurrent, in order to avoid gain compression, nullicnullmanullnullell result nullom nullgnulllevel telecommunications signals, but is certainlnull not desired nullr tnull nullSS signalsnull A classic receinuller testnull nullt nullst as critical for a MultinullNSS receinullernull null simple to enullecute, nullet nullndamental test is tnull sensitivitnulltestnullSimnullnull onullnullrs several easnullmetnullds nullr preciselnull controlling tnull satellite ponuller so tnullt tnull point nullere a receiver looses locnull nullts minimum sensitivitnulllevelnullcan be determinednullEnullallnull, tnull point onullrenull acnullisition can also be determinednull nullor more innullrmation, donullload tnull Spirent nullpplication nullote nullnullundamental nullSS Receiver Cnullracterisation null nulligure null snullnull Simnullnullnulls realnullime ponuller control nullndonull, nulltnullsliders allonullng precise adnullstment onulltnull satellite ponullersnullnull alternative metnulld is to use a nullser action nulle to adnullst tnull ponullers in a timed nullnullnull nullnullRE null: PERnullnullTELLnullE PnullWER CnullTRnull Page 22SPIRENT Application Note nullamming and Interference nullne onulltnull benenulls onullnullultinullnullS operation is tnull increased resilience to internullrence brougnull about bnullmultinull nullenullencnulloperationnullTnull vulnerabilitnull onulltnull nullS Cnull code on Lnullis nullell documented nullee renullrence nullnull null receiver mnullstill sunullnullr similar vulnerabilitnullnullen using nullultinullnullS signals onlnullat Lnull but using Lnull Enull Lnullor otnullr combinations and more robust codes nullll improve its capabilitnull, as it is less linulllnulltnullt an internullrence source nullll obliterate all signals on all nullenullenciesnull nulln tnull donullside, nullSS signals tnullt are not being used nullnullode, nullalileo PRS nullr enullmplenullare still present at tnull receivernulls antenna, and are enullnullctivelnullinternullrence, as tnullnulldo not convenullannullinnullrmation renullired bnulltnull receivernull Test tnull effects null simulator can be used readilnullto test tnull enullnullcts onullinternullrencenullSome onullSpirentnulls models are available nulltnullan internullrence option, allonullng a range onullinternullring signals to be added to tnull nullSS signalnull CW, null, null, pulsed and nulloise signals nulltnull nullll control over eacnullonenulls settings can be generatednull Tnull enullnullcts onullnoise in a dnullamic environment can also be tested, as tnull cnullracteristics onulltnull internullring signal are adnullsted dnullamicallnullin nullrmonnull nulltnulltnull simulated venullclenulls position in relation to tnull internullrence sourcenull Tnull presence onullunnullsed nullSS signals can also be simulated nulltnullnullnulloise and PRSnulloise nullnctions, enabled via a single cnullcnullbonullin Simnullnullnullnulligure null snullnull nullnulloise enabled in Simnullnullnull nullnullRE null: CnullE nullD CnullRnullR CnullTRnull WnullDnullW Page 23SPIRENT Application Note Tnull snullnulls tnull limit null statement tnullt is not onlnulltrue nullr tnull nullture onullnullSS, but also true onulltnull test capabilities or a Spirent Rnullconstellation simulatornullTnulls nullpplication nullote nulls introduced some onulltnull nullnulltopics relating to nullultinullnullS, and snullnull nullst some snap snullts onullnullnulla simulator is tnull rignull cnullice nullr testing tnull enullnullcts onulltnullse issues on a nullSS receivernullTnull business onulldesigning, manunullcturing, integrating and selling nullSS tecnullolognullis driven more and more bnull tougnullcommercial renullirements, especiallnull in a nullrld starting to tentativelnullemerge nullom economic recessionnull Tnull business cases nullr sucnullproducts need to stand up to testing linull never benullrenull nullo one can anullnullrd to manull mistanulls at annullpoint along tnull nullnull, not least nullen it comes to product testingnullnullnvestment in Rnullsimulation as a test and verinullation metnulldolognullnulllps nullep pronullcts sanulllnull anullnullnullom tnull clinullnulledge on tnull rignull patnull nullonulldo nullou test nullour nullSSnull nullor more innullrmation on nullultinullnullS testing, donullload tnull Spirent nullpplication nullote nullMultinullNSS for Tecnullolognullnullenullelopers nullnull Page 24SPIRENT Application Note Test Solutions nullelonullis a summarnullonullSpirentnulls current simulator products nullSnullnull MultinullNSS Constellation Simulator Tnull nullSnullnull series nulls been designed to meet all tnull demanding renullirements onullresearcnulland development teams involved in satellite navigation and positioning snulltemsnullDue to its modular design, tnull nullSnullnull can be readilnull adapted to tnull renullirements onulldinullnullrent applicationsnullnullp to nullRnullcarriers, selected nullom a range onullconstellations and signals, can be accommodated in a single signal generator cnullssisnull null nullSnullnull snulltem comprises a controller computer running Spirentnulls ponullernulll simulation sonullnullre Simnullnull, and a signal generator connullured to meet specinull test needsnullnullultiple cnullssis can be combined to nullrm an integrated, conullrent signal generator inullmore signals or outputs are renullirednullnull enullensive range onullsnulltem enullensions allonull users to tailor tnullir snulltem to tnullir specinull needs, todanull and in tnull nullturenull Standard capabilities enabled tnullougnull Simnullnull include simulation onull atmospnullric enullnullcts, multipatnullrenullctions, terrain obscuration, antenna reception gain and pnullse patterns, dinullnullrential corrections, tranullctornullgeneration nullr land, air, sea and space venullcles and comprenullnsive error generationnull null easnullto use grapnullcal user internullce nullnullnullallonull modinullation onulla nullde range onullvariables nullom prenullet denullults, enabling tnull user to nullcus tnullir time on tnull areas onulltest important to tnullmnullComplete scenarios are readilnullsnullred betnulleen snulltems, supporting collaborative activities and speeding up tnull Rnull cnullclenull Page 2nullSPIRENT Application Note nullSnullnull MultinullNSS Constellation Simulator Tnull nullSnullnull supports annullcombination onullnullSnullnullS, nullnullnullS and nullalileo Lnull signals and provides accurate, repeatable combined nullultinullnullS signalsnullTnull nullSnullnull can be connullured nulltnullup to null cnullnnels onullone constellation onlnullor nulltnullmultiple constellations, nullr enullmple: nullnullS onlnull nullnullnullnullS onlnull nullnullalileo onlnull nullnullS and nullnullnullS nullnullS and nullalileo nullnullS, nullnullnullS and nullalileo nullp to null cnullnnels are supported nulltnullnull cnullnnels onullsimulation per constellationnull Tnull nullSnullnull is available nulltnulla range onull sonullnullre capabilitnullto suit dinullnullring test renullirementsnull Simnullnull is Spirentnulls nullllnullnullnullble simulator sonullnullre suite and nulluld tnullicallnull be renullired in tecnullolognulldevelopment and Rnull applicationsnullSimnullnull onullnullrs a complete and nullnullble scenario generation capabilitnullincluding control onulltnull constellations, propagation, terrain obscuration, antenna patterns, multipatnull venullcle tranullctornulland a range onullerror modelsnull nullor environments nullere repeat testing using tnull same test cases is needed, nullr enullmple verinullation testing, Spirentnulls SimREPLnullnull sonullnullre is availablenull SimREPLnullnull supports operation onulltnull simulator replanullng prenullenulled scenarios and is ideal nullr repeat comparative measurementsnull Scenarios nullr use nulltnullSimREPLnullnull can be obtained nullom a number onullsources including an online scenario generation tool available at no additional cnullrge to customers under nullrrantnullor nulltnulla support contractnull SimREPLnullnullplus allonull users to generate scenarios locallnullnulltnullnullatures comparable to tnull online tool available to supported SimREPLnullnull usersnullnulln addition, SimREPLnullnullplus enables tnull user to denulle venullcle motion remotelnullor using a nulle in tnull renullired nullrmatnull Page 2nullSPIRENT Application Note nullSnullnull MultinullNSS Constellation Simulator Tnull nullSnullnull nullultinullnullS Signal nullenerator nulls been designed specinullallnullnullr nullgnull volume production test applications nullr devices tnullt use commercial nullSnull SnullS, nullnullnullS andnullr nullalileo receiversnull Controlled testing is vital in ensuring correct assemblnulland verinullation onull enullected pernullrmance parameters in nullS onlnulland nullultinullnullS manunullcturing environmentsnullSpirentnulls nullSnullnull provides a robust single cnullnnel testing solution nulltnulltnull minimum onulloperator interventionnull Tnull nullSnullnull can be connullured nulltnullone cnullnnel onulla specinull constellation or nulltnull multiple constellations, nullr enullmple: nullnullS onlnull nullnullnullnullS onlnull nullnullalileo onlnull nullnullS and nullnullnullS nullnullS and nullalileo nullnullS, nullnullnullS and nullalileo nullor nullS LnullCnull code test applications, tnull nullSnullnull nullatures, internullces and specinullation are tnull same as tnull Spirent nullSnullnull product tnullt is nulldelnullspecinulld nullr manunullcturing test applicationsnull nulleneration onullsignals nullom tnull various constellations is enabled bnulllicence nullnullnull nullnullall licence nullnull are present tnull nullSnullnull can generate a single nullS signal, a single nullnullnullS signal and a single nullalileo signal concurrentlnullnull Tnull nullSnullnull is designed nullr easnull integration into production test environmentsnullnull comprenullnsive remote control internullce enables control onulltnull unit via standard internullces, including nullEE4null and nullnull nullor operation in tnull laboratornull, nullr enullmple as a single cnullnnel precision nullSS signal generator nullr Rnulldesign nullrnull a nullnulldriven sonullnullre utilitnull, SimCnullnull is suppliednull Page 2nullSPIRENT Application Note nullSnullnull Record null PlanullacnullSnulltem nullring tnull Complenulltnullof tnull nullSS nullorld nullacnullInto nullour Lanull Consumer navigation and positioning products onullen need to pernullrm under enullremelnullcnullllenging signal environments, nullom inside onullce buildings to urban cannullons and rural mountain topsnull Recreating tnullse environments snulltnullticallnull using a simulator, nullr enullmple, tanulls a considerable amount onulltime, nullonulledge and snullllnull nullonullnullou can capture and replanulltnull nullll ricnulless onulltnullse enviroments at tnull pusnull onulla button nulltnulltnull nullSnullnull Record nullPlanullacnull nullenenulls: null Complete solution designed to capture complenullrealnullorld environments and replanullnulltnulloptimal nullelitnull nullpernullrmance null Reduces time and monenullspent on nullld tests null nullmproves device pernullrmance bnull eliminating runnullonullun cnullnges null Compatible nulltnulla nullde range onull test applications nullenullnulleatures: nullnullne toucnullrecord and replanull null nullnullnull internal nullrd drive nullp to null nullurs onullsignal recordingnull null nullnternal batternullallonull up to one nullur onullinnulleld recording null Tnullnullit Sampling null null nullour Testing null Remote Control null Test nullutomation Learn more about tnull nullSnullnull Record PlanullacnullSnulltem Page 2nullSPIRENT Application Note nullor More Information Please visit our nullebsite: nulltp:nullnullnullnullpirentnull comnullositioning and do not nullsitate to contact nullour nearest Spirent representative nullr more detailed innullrmationnullTo nulld tnull appropriate contact details please visit tnull nullontact nullsnull page on tnull nullebsite and select nullour location and applicationnull Page 2nullSPIRENT Application Note CONTACT null nullot a smartpnullnenull If you have a smartphone download a QR Code reader and then point your phone camera at the QR Code to read the graphic. Spirent Communications null4 nullnull nullnullnull globalsalesnullpirentnullom nullnullnullpirentnullomnullositioning Spirent nullederal Snulltems null 7null nullnullnullnull innullnullpirentnullderalnullom nullnullnullpirentnullderalnullom nullaceboonull Linnulldnulln Tnulltter Tecnullorati nulloogle nullunull Digg Delicious Reddit Stumbleupon nullnullnot snullre tnulls documentnull DnullnullnullnullSnull nullnull RevnullnullnullSept nullnull nulle are adding nenullcontent to our nullenullite on a regular nullsisnull nullonullarnulltnulls linnull nullnullnullpirentnullomnullositioning nullisit tnull Spirent nullSS nullognulltnullre are currentlnullonuller null posts nulltnull2 to 3 nenullposts added eacnullnulleenull Catcnullup on nullatnulls nenullnull nullnullnullpirentnullomnulllognullositioningnullspnull Need more informationnull gnssnullolutionsnullpirentnullom