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Application Note: Simulating UTC Leap Second Insertion Events

Simulating UTC Leap Seconds

Every so often, the world’s primary time standard—Coordinated Universal Time (UTC)—is adjusted to account for variations in the rotation of the Earth. To ensure GPS receivers are able to handle these leap second insertion events correctly, careful testing is a must.

Download the Application Note and discover how to simulate leap second insertion events during GPS receiver testing. Topics include:

  • Why leap second insertion events are necessary in the GPS system
  • How the GPS system manages leap second insertion events
  • Using a Spirent RF simulator to test GPS receiver response to UTC adjustments

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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    Simulating UTC Leap Second Insertion Events APPLICATION NOTE Spirent Communications PLC Paignton, Devon, TQ4 7QR, England Webnull nulltpnullnullnullnullpirentnullomnullositioning Telnull 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 nulludience 4 Introduction 4 RnullSimulation null Tnullical nullS Simulators null Time null nullS time nullPSTnull null Simulating a Leap Second Event 7 nullavigation data modinullation null Renullrenced Documents null nullppendinull null Page 3SPIRENT Application Note Audience Tnulls nullpplication nullote is nullr designers, developers, integrators and testers onull nullSS receivers or snulltems nullo need to ensure tnullir products nullll pernullrm in tnull intended environmentnull Spirent recommends nullou nullve a basic understanding onullsatellite navigation principles and anullreness onullRnullsimulation using Spirent simulators controlled bnullSimnullnull sonullnullre is desirablenull Introduction Tnullre is a steadnullgronullnullin tnull use onullnullSS in nenulland enullsting marnulltsnull Consenullentlnull, tnullre is an increasing reliance on nullSS tecnullolognullnull Witnulltnulls in mind, it is important nullr designers, manunullcturers and consumers onulltnullse products to understand nullat to enullect nullom sucnull snulltemsnullTnulls includes nullrmulating an understanding onulltnull limitations and problems onullnullSS tecnullologiesnull Tnulls nullpplication nullote discusses nullC leap second insertion events in relation to tnull nullS snulltem, nullnulltnullnullare necessarnull, nullnulltnullnullare managed bnulltnull snulltem, and nullnullto test a nullS receiver using an Rnull constellation Simulator to ensure it nullndles a leap second insertion event correctlnullnull Page 4SPIRENT Application Note nulligure null RnullSimulation nulllonull RF Simulation null RnullConstellation Simulator reproduces tnull environment onulla nullSS receiver on a dnullamic platnullrm bnullmodelling tnull venullcle and satellite motion, signal cnullracteristics, atmospnullric and otnullr enullnullcts, so tnullt tnull receiver nullll actuallnull navigate, in tnull lab, according to tnull parameters onulltnull test scenarionull nullnullits vernullnature, simulation is a representation onulltnull real nullrldnullSimulation cannot reproduce tnull nullll ricnulless onullreal nullrld conditionsnull null common misconception is tnull need to enullctlnullreplicate real nullrld conditions nullr a nullSS test to be validnull nullonullever, application onullrepresentative enullnullcts via simulation is proven nullver some null nullears onulltestingnullto enullercise receivers and adenullatelnullidentinull tnullir limitations allonullng nullr design centring and optimisationnullnullore importantlnull, it gives complete repeatabilitnull, control and enullct nullonulledge nulldonull to bit level nullonulltnull signal stimulating tnull receivernull Tnulls is not possible nullen using real nullSS signals nullr test purposesnullWe snulluld loonull upon simulator testing as representing tnull real nullrld, ratnullr tnulln replicating itnullContinued, successnulll deplonullent onull receiver designs in mannullapplications proves tnullt tnull simulators being used nullr tnullir development and verinullation are accurate in tnullir implementation onulltnull nullSS environmentnull nulligure nullsnullnull tnull concept onullsimulation nullsing a nullSnullnull simulatornull Tynullcal nullS Simulators nulll tnull tests discussed in tnulls nullpplication nullote can be pernullrmed using Spirentnulls multinullnullnnel simulators nullom tnull nullSnullnull, nullSnullnull and nullSnullnull seriesnullTnull tests can also be pernullrmed on previous platnullrms enullnullnullSnullnull and null77nullnull Simnullnull is tnull control and scenario denullition sonullnullre nullr tnullse simulatorsnull Simnullnull can also create scenarios to be run on SimREPLnullnull, nullicnullis tnull scenario replanulland control sonullnullre nullr tnull nullSnullnull simulatornull nullor nullrtnullr innullrmation on Spirentnulls range onullSimulators, please contact nullour local Spirent representative, or visit nullnullnullpirentnullomnullositioning null Page nullSPIRENT Application Note Time Since tnull introduction in tnull late nullnulls onulltnull nullst atomic clocnull based on tnull resonance onulltnull caesium atom, available clocnullaccuracnullimproved bnullorders onull magnitudenullTodanull, tnull International nullureau onullWeignulls and nulleasures, or nullureau International des Poids et nulleasures nullIPnull, in nullrance is cnullrged nulltnullproviding tnull time standardnullCoordinated nullniversal Time nullTCnull Tnull nullPnullcollects data nullnterestinglnull, via nullS in partnullnullom more tnulln nullnull atomic clocnull and a nullnullprimarnullnullabsolutenull nullenullencnullstandards nullom more tnulln null institutions around tnull nullrldnull nullnce a montnull nullPnulluses tnulls data to produce tnull standard international renullrences nullr nullenullencnulland time, International nulltomic Time nullTnullnulland nullC, nullicnullis enullal in rate to Tnull, but adnullsted evernullso onullen bnullan integer number onullseconds to account nullr variations in tnull rotation onulltnull Eartnull nullS time nullPSTnull nullST is a composite time scale denulled on tnull basis onullmeasurements nullom a number onullatomic nullenullencnullstandards in use at monitoring stations and onnulloard tnull satellitesnullIt began on tnull nullnullnullanuarnull nullnull, and is denulled in realnullime and is continuous nullo leap second insertionsnull nullST is nullsteerednull to nulltnulln nullmicrosecond onulltnull realnullime realisation onullnullC nullicnull is provided bnulltnull nullnited States nullaval nullbservatornullnullnullnullnullIn practice, nullST nulls been maintained to nulltnulln appronullmatelnull null nanoseconds onullnullCnullnullnullnullnullonullever, because onullits continuitnull, nullST is a certain number onullnullole seconds plus a nullaction onulla microsecond dinullnullrent to nullCnullnullnullnull In order nullr nullS receivers to provide to tnullir users time according to nullC, tnull current nullST to nullCnullSnullnullonullnullet must be declared bnulltnull nullSS snulltemnull In addition, nullen tnull leap second insertion event occurs and tnull onullnullet increases, receivers must recognise it and be able to adnullst tnullir reported time accordinglnullnull To enable tnullm to do tnulls, a series onull cnullnges occur to tnull navigation message being broadcast bnulltnull nullSS snulltemnull In tnulls nullpplication nullote nulle nullll consider nullnullnullS implements leap secondsnull nulltnullr nullSS snulltems nullucnullas nullalileonull implement tnullm in a similar nullnullnullRenullr to tnull relevant snulltemnulls SISnullCD nullr details on eacnullspecinull implementationnull nullormallnull, leap second events occur at midnignull on nullst December or nulltnullnullune in a given nullear, nullnullever tnull nullS SISnull ICD does not specinull a particular date on nullicnulltnullnullmanulloccur, so nullr tnull purpose onulla receiver test, nulle must assume it can nullppen at annulldatenullnullS leap second event implementation in tnull navigation messagenull Page nullSPIRENT Application Note Tnull navigation data message as broadcast bnulltnull orbiting satellites is tnull mecnullnism used to innullrm receivers onulla leap second eventnullTnull nullllonullng parameters are relevant to denulling a cnullnge in tnull leap second onullnullet in tnull navigation datanull Tnullse parameters are contained in sub nullame 4, page null onulltnull navigation datanull null WnullsnullnullWeenullnullumber in nullicnulltnull leap second event nullll occur nullWord null nullits null nullnullnull null DnullnullDanullnullumber on nullicnulltnull leap second Cnullnge nullll occurnullnullundanullis Danull null nullWord null nullits null nullnullnull null tLS nullCurrent leap seconds onullnulletnullnull Word null nullits nullnullnull null tLSnullnullnullenull leap second value nullnullnullvalue at cnullngenull Word null, nullits nullnullnull Wnullsnulland Dnullenullnullctivelnulldenulle tnull time tnull leap second cnullnge nullll occurnull nullor enullmple, assume tnull current date is nullnullnullanullnullnull, tnulls is a nullondanull, so Dnull nullll be null and Wnullsnullnullll be 4nullnull Tnull leap second cnullnge nullll occur at tnull end onulltnulls danulland nullll transition nullom tnull nullLS value to tnull nullLSnullvaluenull Tnull appendinullin at tnull end onulltnulls document gives tnull ICDnullPSnullnull nullll denullition onullnullCnull Simulating a Leanull Second Enullent We nullll loonullat tnullee metnullds onullsimulating a leap second eventnull null nullavigation data modinullationnull null Implementation using tnull Simnullnull nullInull null Implementation using tnull nullser Denulled Data nullDDnullnullcilitnullnull Page null SPIRENT Application Note Nanullgation data modinullation null previouslnullmentioned, tnull parameters denulling a leap second insertion event are contained in page null onullsub nullame 4 in tnull nullS navigation datanullSimnullnull nulls a navigation data editor nullicnullallonull nullou to manull bitnullevel modinullations to annullpart onulltnull navigation message, nullicnullcan be added and removed at specinulld timesnull Tnull editor is similar in operation to tnull otnullr editors nulltnulln Simnullnullnullnulligure nullsnullnull tnull navigation data editor in SimnullnullnullRenullr to renullrence nullnullr nullrtnullr detail on tnull operation onulltnulls editornull Snullcinulling nulllsnull Tnull nullS Weenullnumber Wnullis denulled in tnull range nullnullnullnull Tnulls is a null bit value, as specinulld bnullsub nullame null nullrd null bits nullnull onulltnull nullS nullnullData nullCountnull nullor Wnullsnull, tnull nulleenullnumber is truncated to tnull least signinullant nullbits, tnull nullll nulleenull number being implied bnulltnull value onull Wnullas given bnulltnull current nullcountnull nullTnull dinullnullrence betnulleen Wnulland Wnullsnull is alnullnull nullnullnull To specinull a nulleenullnumber onull4null nullr Wnullsnull, nullou nulluld nullst convert to binarnull to get nullnullnullnullnull Removing nullnullnull nullo leave tnull renullired nullbitsnullnullll give nullou tnull nulleenullnumber as nullnullnullnullnull nullote tnullt some nulleenullnumbers nullll renullire removal onullnullnullnullsnull nullS nulleenullnumbers nullollnullvernull to null nullen nullnull is reacnulldnullIt is not possible to tell nullicnullis tnull current rollnullver period nullom Wnull Snullcinulling onullnull Specinullation onulltnull Dnullvalue is simple as it is denulled as tnull danullin tnull nulleenulltnullt tnull leap second cnullnge snulluld occur at tnull end onull, nullere nullnullSundanullnull Convert tnull data nullom decimal into binarnulland nulll tnull preceding bits nulltnullnullerosnull nullor enullmplenull Danullnullnullnull in binarnull, so tnulls snulluld be entered in tnull nullav Data nullo nulll tnull renullired nullbitsnullas nullnullnullnullnull nulligure null Simnullnull nullavigation Data nullodinullation Editor Page nullSPIRENT Application Note Snullcinulling onullnull Specinullation onulltnull Dnullvalue is simple as it is denulled as tnull danullin tnull nulleenulltnullt tnull leap second cnullnge snulluld occur at tnull end onull, nullere nullnullSundanullnull Convert tnull data nullom decimal into binarnulland nulll tnull preceding bits nulltnullnullerosnull nullor enullmplenull Danullnullnullnull in binarnull, so tnulls snulluld be entered in tnull nullav Data nullo nulll tnull renullired nullbitsnullas nullnullnullnullnull Specinullation onullnullLS and nullLSnull nulltnullnullLSnulland nullLS are specinulld using nullnullitsnull Tnull range onulltnullse values is onlnull limited bnulltnull nullld sinullenull nullonullever, as at nullan nullnull tnull number onullleap seconds separating nullC and nullST is nullnull Tnull dinullnullrence betnulleen tnull nullLSnullandnullLS must be onlnullnullnullnullsecondnullTnull leap second nullll never cnullnge bnullmore tnulln nullsecond nullnd in practice, nullll onlnullever increasenull null nulltnulltnull specinullation onulltnull Dnullparameter, nullou convert tnull leap second decimal value into binarnull, padding leading bits nulltnullnull so null nulluld be entered as nullnullnullnullnull nullotenullnulltnullugnullin tnull real nullrld tnull dinullnullrence betnulleen nullLSnulland nullLS nullll onlnullever be nullsecond, Simnullnull does not applnullannullrestrictionnullEntering a larger value is entirelnullpossible, but manullcause unpredictable enullnullcts on a receivernull Enullmple leap second insertion using navigation data modinullationnull Tnulls enullmple snullnull nullnullto create a scenario nullicnullincludes a leap second event insertion using tnull navigation data modinullation metnulldnull Tnull scenario parameters nullll be as nullllonullnull null Scenario Start Date nullnullnullnullanullnullnullnull nullnulls is a nullondanullnullDanullnullnull null Start Time nullnullnullnullnull nullnullmin benullre leap second insertion event nullll occurnull nulltLS nullnitial Leap Second nullaluenullnullnullnull null tLSnullnullnullalue Leap Second nullll cnullnge tonull nullnullnull null WnullsnullnullWeenulltnull cnullnge nullll occurnullnull4null nullame as scenario start nulleenullnull null Dnullnullanullonullnulleenulltnull cnullnge nullll occur at tnull end onullnullnullnull nullame as scenario start danullnull nullirst nullou need to set tnull scenario date, start time and duration in Simnullnullnull To do tnulls, enter tnull parameters as snullnull in nulligure null nullote tnullt tnull nullCount, nullS Weenullnumber and TnullWs are automaticallnullnulllednullnnull nulligure null Simnullnull Date Time and Duration Editor Windonull Page nullSPIRENT Application Note Tnull nenull step is to edit tnull nullS constellation nulle and enter tnull relevant data into tnull nullav Datanull So in tnull enullmple above nulle nullst need to convert tnull values onullnullLSnull, nullLS, Wnullsnull, Dnullinto binarnullnull nullLS nullnull Decimal null nullnullnullnull nullinarnull null nullitsnull nullLSnullnullnull Decimal null nullnullnullnull nullinarnull null nullitsnull Wnullsnullnull4null decimal nullnullnullnullnull nullinarnull null nullitsnull Dnullnullnulldecimal nullnullnullnullnull nullinarnullnull nullitsnull nullonullmanull tnull nav data cnullnges using tnull editor snullnull in nulligure nullbnullpernullrming tnull nullllonullngnull null Select tnull command tnulle nullegacnullnullnull Data nullodnull null Ticnulltnull nullallnull ticnullbonullnenull to SnullD nulltnulls ensures tnullt tnull cnullnges nullll be transmitted in tnull nav data bnullall satellitesnull nullEnter tnull sub nullame as 4null nullEnter tnull Page as nullnull nullEnter tnull Word as null null Enter tnull ΔtLS, Wnullsnull, and Dnull binarnullvalues null sets onullnullbits, previouslnulldenulled above as nullnullnullnullnullnullnullnullnullnullnullnullnull beginning at bit null null Enter tnull time tnullt tnulls cnullnge nullll be valid nullr, nullr enullmple, tnull duration onulltnull scenario beginning at tnull start time onull tnull scenarionull null Clicnulltnull nullnull Ins nullenullrenull button to insert tnull commandnull null nullsing a nenullcommand, enter tnull data nullr ΔtLSnull, bnullsetting tnull bits to nullnullnullnull, starting at bit null null Enter nullnullnullr all tnull remaining bits nullto nullnull nullEnter tnull Word as nullnull null null nulltnulltnull previous command, ticnulltnull nullnulllnull bonullnullr SnullD, set tnull sub nullame to 4, tnull Page to null and tnull start nullstop times to tnull duration onulltnull scenarionull null Clicnulltnull ‘ Ins nullternull button to insert tnull command anuller tnull one alreadnull in tnull listnull nullou snulluld nonullnullve botnullcommands in tnull command list as snullnull in nulligure 4null null nullenull, clicnullnullnull and name nullsave tnull nullenull nullou nullve nonullset up tnull conditions to simulate a Leap Second event occurring at midnignull on nullnullnullanullnullnullnull nulligure 4 nullodinulld nullavigation Data Page nullSPIRENT Application Note Simulating a leanullsecond insertion using nullI data entry null mentioned previouslnull, leap second insertions generallnulloccur on tnull nullst December or nulltnullnullune in a given nullearnull Tnull navigation data modinullation enullmple snullnull nullnullto simulate a leap second event tnullt can occur on annulldate nullas tnulls is, in tnullornull, possible nullonullever unlinulllnullnull Simulating leap second events using tnull Simnullnull nullI is mucnulleasier, but is limited to tnull nullst December or nulltnullnullune datesnull To setnullp a leap second event using tnull nullI, pernullrm tnull nullllonullngnull null In tnull Scenario tree, under nullptionsnull ticnull tnull bonullnulleap Second atnull nullee nulligure nullnull null Doublenulllicnulltnull nulle to displanulltnull nulleap Second occurs atnull bonullnullee nulligure nullnull null Select eitnullr nullst December or nulltnull nullune, and enter tnull renullired nullear nullee nulligure nullnull nullClicnullnullnull Simulating a leap second insertion using Simnullnullnulls nullser Denulled Data nullDDnullnullcilitnull Simnullnullnulls nullser Denulled Data nullcilitnull allonull tnull user to denulle some onulltnull data normallnulldenulled in tnull Signal Sources nulle, bnullmeans onullusernullupplied nullCII nullesnullnullne sucnullnullD nulle is a nullav Data nullodinullationnull nullenullIn a similar nullnullto tnullt described in nullnull4, tnull usernullenulled nulle overnullites tnull navigation data normallnullgenerated bnull Simnullnullnull Tnulls is acnulleved bnullspecinulling tnull sub nullame, page and nullrd to be cnullnged in tnull nullavigation Data, togetnullr nulltnulltnull appropriate bits to be cnullnged in tnulls nullrdnullTnulls can be applied to all or specinulld satellitesnull Tnull nullav Data modinullation nulle is an nullCII nulle containing records nullinesnullnulltnulltnull nullllonullng nullrmatnull Comment Record Tnullse are records onullup to null cnullracters preceded bnullnullnull use tnullse to add comments nullr a titlenullas renullirednull Tnullse records manullbe placed at annull point in tnull nullenull nulleenullNumnullr Record Tnulls specinulls tnull nullS nulleenullnumber to nullicnulltnull data is to be initiallnullrenullrencednull Tnull nullrmat isnull nullEnull nnnn nnnn is tnull nulleenullnumber, range nullto nullnullnullWeenullnumber rollover nullll be implicit according to tnull start time onulltnull scenarionull nulligure null nullpplnullng a Leap Second in Page nullSPIRENT Application Note Tnull Weenullnullumber record onlnulloccurs once in eacnullnulle, tnulls is nullllonulled bnulla senullence onullrecords nullicnulldenulle tnull cnullnges to be applied nullr all anullnullcted satellites nullom a specinulld timenullEacnullset onulldata consists onulltnull nullllonullngnull Time Record Time onullnulleenullnullom nullicnulltnull cnullnges are to be applied, enullressed as nullcount nullnullnullnumber onullnullnullsecond epocnull into tnull nulleenullnullTnull nullrmat isnull TOnullnullnnnnnn nnnnnn is tnull time onullnulleenull Tnulls must be on a sinullsecond epocnull range nullto 4nullnullnull Tnull time record is nullllonulled bnulla number onullsets onulldata nullr eacnullsatellite nullr nullicnull nullav Data amendment is renullirednullTnulls comprises a single Satellite ID record and a variable number onullnullav Data records nullicnullallonulla specinulld nullav Data nullrd to be cnullngednull Satellite InullRecord Tnull ID onulltnull satellite nullr nullicnulltnull data cnullnges are to be appliednullTnull nullrmat isnull Snullnull nn nn is tnull satellite IDnullInulltnulls is set to nullero tnulln tnull specinulld amendments applnullto all satellitesnullRange nullto nullnull Nanullnullata Records null series onullrecords denulling tnull cnullnges renullired nullr tnull given satellitenull Tnull nullrmat isnull SF nnullP n2null n3null n4nullnull anulldenull nnull nullis tnull number onulltnull subnullame to be cnullngednullnull applies to all subnullamesnull n2 nullis tnull number onulltnull page to be cnullngednullnull applies to all pages onull tnull given subnullamenull n3 nullis tnull number onulltnull nullrd to be cnullngednullnull applies to all nullrds onulltnull given subnullamenullagenull n4 nullis tnull nullst bit onullnullS nullav Data nullrd to be cnullngednull nnull nullLast bit onullnullS nullav Data nullrd to be cnullngednullnullS bit range is nullom nullnullnulltnull paritnullbits nullnullnullnullmanullnot be edited and nullll be correctlnulldenulled bnulldenullultnull anulldenull is a nullnulldecimal cnullracter string denulling bits to be used as bits nullnull in nullS nullav Data nullrd, sucnulltnulltnull Eacnullcnullracter represents nullur bits onulltnull null bit editable rangenull Tnull most signinullant bit onullnullanullcorresponds to bit nullonulltnull nullS nullav nullrdnull Tnull least signinullant bit onullnullnullnullcorresponds to bit null onulltnull nullS nullav nullrdnull nullnlnulltnullse bits nulltnulln tnull specinulld range onulln4nullnullare usednull nullurtnullr Satellite ID and nullav Data records to be applied nullom tnull given TnullW nullllonull, as renullired, until tnull nenull TnullW record null inullannull is accessednullnulldditional sets onulldata nullr later times tnulln nullllonullas needednull nullotesnull null Tnull nullav data cnullnges are applied indenullitelnulluntil a nenullset onullcnullnges is denulled nullr a given satellite at a later timenullnulll previous amendments nullr tnulls satellite are tnulln overnullitten, so inullno nullav Data records nullllonulltnull Satellite ID record tnull sonullnullre nullll revert to generating tnull denullult nullav Datanull null Tnull cnullnges denulled in tnulls nullnullare to be applied benullre tnull nullav Data sub nullames are passed to tnull SnullS sonullnullre nullnullapplicablenull so tnullt nullrtnullr manipulation onulltnulls data manullbe pernullrmed at tnull SnullS stagenull null nulllannulllines in tnull nulle nullll be snullppednull Page nullSPIRENT Application Note Tnull nullD nulle appicable to tnull enullmple nulle nullve been using nulluld be as nullllonullnull ! Simulation of leap second event. Date 5th May 08, Time 23:40:00 ! Change from 14 to 15 Seconds. WEEK: 454 TOW: 0 SVID: 0 ! Set the values of Delta tLS, WNlsf, and DN that are in Subframe 4, page 18 ! Word 9, bits 1 to 24. SF 4:P 18:W 9:B 1-24: 0FC602 ! Set the value of Delta tLSF, this is in Subframe 4, Page 18, Word 10, bits 1 to 8. SF 4:P 18:W 10:B 1-8: 0F0000 ! end nullnce tnulls nulle is denulled, save tnull nulle and select it bnullticnullng nullnable usernullenulled data under tnull nullS Constellation nullile in tnull scenario tree, tnulln nullen tnull subnullist appears, ticnullng tnull nullav data mod nulle and selecting tnull nulle nullou nullve nullst created, as snullnull in nulligure null Wnulln tnull scenario is run, tnull data in tnull nullav data mod nulle nullll be applied accordinglnullnull nulligure null Enabling nullD in tnull scenario nulle tree Page nullSPIRENT Application Note Simulating a leanullsecond insertion using tnull Unull nulllonulll Nanullnullata FIle Tnull nulllobal nullav Data nulle allonull tnull data nullr tnull Leap Second event to be entered directlnullnull null enullmple generic nulllobal nullav Data nulle nullr one Snullis snullnull in nulligure 7null null nullou can see, nullou can directlnullenter in tnull values onullWnull, Wnullsnull,Dnull nulllsnull, and tLS and do not nullve to pernullrm binarnullor nullnull conversions on tnull parametersnull nullonullever, tnull problem nulltnullusing tnulls metnulld is tnullt nullou must also specinull all onulltnull otnullr parameters nulltnulln tnull nulle, nullr enullmple, Ionospnullric cnullracteristics, Satellite nullaltnull otnullrnullse tnullnullnullll be overnullitten nulltnullnull To enable tnull nulllobal nav data nulle, ticnulltnull bonullnullr nulllobal nav data nullenull in tnull scenario nulle treenull Wnulln tnull scenario is run, tnull data in tnull nulllobal nav data mod nulle nullll be applied accordinglnullnull null correctlnullnullnctioning receiver, nullicnull is navigating nullom tnull simulatornulls signal, snulluld detect and applnulltnull leap second insertionnull Tnulls manullbe observed bnullmonitoring tnull receivernulls nullC time data outputnullTnull time count nullll appear to stop nullr nullsecond benullre continuingnullnullor enullmple, observing tnull seconds on a receivernulls nullC time displanullmanullreveal tnull nullllonullng 4nullnullnullnull 7nullnull, nullere 7 nulls tnull time at nullicnulltnull leap second even occurrednull It snulluld be noted tnullt a receiver mignull not actuallnull implement tnull leap second adnullstment on tnull nullnullnullmidnignull boundarnullnullSome receivers manull tnull cnullnge benullre tnulls timenullTnull best nullnullto cnullcnulltnullt tnull implementation nulls occurred is to log tnull receivers nullC time data to a nulle, and analnulle tnulls nulle anuller tnull test nulls nullisnulld, ratnullr tnulln trnullng to pnullsicallnullobserve tnull time countnull nulligure 7 Enullmple nulllobal nullav Data nullile Page nullSPIRENT Application Note Renullrenced nullocuments null ISnullPSnullnullD nullavstar nullS Space Segmentnullavigation nullser Internullce Specinullation, Revision D, 7tnullDec nullnull null Dnullnullnullnullnull Simnullnull Sonullnullre nullser nullanual nullatest issuenull Anullendinull Renullrence null section nullnullnullnullnullnull provides a detailed enulllanation onullnullnulltnull nullS navigation data message nullndles nullC data and tnull circumstances leading up to, during and anuller a leap second eventnull We tnullrougnullnullrecommend studnullonulltnullt documentnullnullere nulle nullsnullonlnullto provide a brienullcommentarnullto supplement nullat nulls been described tnulls nullr in tnulls application notenull Wnulln a nenullleap second event is scnullduled to tanull place tnullre are tnullee pnullses nullicnulluser enullipment must pass tnullougnull null Tnull time benullre tnull leap second event, greater tnulln nullnullurs benullre nullser enullipment nullll use tnull value nullrnullLS, tnull nullcurrentnull nullCnullonullPS onullnullet null Tnull time surrounding a leap second event, nullnullurs benullre to nullnullurs anuller nullser enullipment nullll begin a transition nullom tLS to nullLSnull, nullom tnull nullcurrentnull to tnull nullnenullnull nullCnullonullPS onullnullet null Tnull time anuller tnull leap second event, greater tnulln nullnullurs anuller nullser enullipment nullll use tnull value nullr tLSnull, tnull nullnenullnull nullCnullonullPS onullnullet It is a common misconception tnullt tnull nullS navigation message nullll be nullmmediatelnullnull updated so tnullt nullLS tanulls tnull value onullnullLSnull, enabling tnull user enullipment to continue using nullLSnull Tnulls is not tnull case and in nullct tnull navigation message nullcouldnull remain uncnullnged nullr up to several nullears anuller a leap second eventnullTnull critical point to note is tnullt user enullipment is enullected to assess tnullir current time against tnull values nullr WnullSnulland Dnullin tnull navigation messagenulltnull nulleenulland danullnumbers nullicnull indicate nullen a leap second is scnullduled to tanull placenullInulltnull current time is nullenullrenull tnull time denulled bnulltnullse parameters, use nullLSnullInulltnull current time is nullanullernull tnull time denulled bnulltnullse parameters, use nullLSnullnull nullnullassociation nulltnullSimnullnull navigation data output, it is correct tnullt tnull nullrnulld enullmples in tnulls application note nullll result in null CnullnullE to tnull value nullr nullLS anuller tnull time nullr tnull leap second event nulls passednullTnulls is in direct accordance nulltnull renullrence null Snulluld users nullsnullto nullrce nullLS to tnull value nullr nullLSnullanuller tnull leap second event tnulln tnullnullmust use tnull process described in section nullnull4, nullnullnullor nullnull7, adding an appropriate dataset tnullt updates tnull navigation message accordinglnullnull Page nullSPIRENT Application Note CONTACT US Snullrent Communications null4 nullnull nullnullnull globalsalesnullpirentnullom nullnullnullpirentnullomnullositioning Snullrent Federal Systems null 7null nullnullnullnull innullnullpirentnullderalnullom nullnullnullpirentnullderalnullom nully not snullre tnulls documentnull nullot a smartnullonenull If you have a smartphone download a QR Code reader and then point your phone camera at the QR Code to read the graphic. DnullnullnullISSnull nullnull Revnullnullnullnullug nullnull nullaceboonull LinnulldIn Tnulltter Tecnullorati nulloogle nullunull Digg Delicious Reddit Stumbleupon nulle are adding nenullcontent to our nullenullite on a regular nullsisnull nullonullarnulltnulls linnull nullnullnullpirentnullomnullositioning nullisit tnull Snullrent nullSS nullognulltnullre are currently onuller null nullsts nulltnull2 to 3 nenullnullsts added eacnullnulleenull Catcnullunullon nullatnulls nenullnull nullnullnullpirentnullomnulllognullositioningnullspnull Need more innullrmationnull gnssnullolutionsnullpirentnullom