Instruction Manual

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GNAV540UserManual
7430‐0808‐01Rev.B
Page37
1PPSOutputInterface
The1PPSoutputsignalisprovidedbytheinternalGPSreceiver(whenGPStimingisknown)ontheGNAV540.The
1PPSoutputsignalisopen‐collectorandshouldbeinterfacedtoarising‐edgetriggerwithpullupresistorbetween
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S.
1kand10kohms. TheGNAV540synchronizessensordatacollectiontothis1PPSsignalinternallywhenavailable
Therefore,the100Hznavigationalgorithmwillrunexactly100timeseachsecondwithnoslipwhenlockedto1PP
Packetdataisvalidontherisingedgeof1PPSand10msboundariesthereafter.Thereis,however,upto500µsof
additionallatencyinsensordatacollection.If1PPSisprovidedbytheinternalGPSreceiverinNAVproducts,then
therisin e
hardwareStatus
gedgeof1PPSwillcorrespondtotheUTCsecondboundary.Whenthesystemissynchronizedto1PPS,th
Æunlocked1PPSflagwillbe
zero;otherwise,theflagwillbeone.
Figure5
belowshowsthesequentialorderofthesignalpresentat1PPSOUTpin.TheonePPSsignalisalignedto
hesamplingclockof23.104MHz,whichresultsinthetimingresolutionof43ns.
t
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Figure51PPSOutputSignal
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