Instruction Manual

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Page82
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GNAV540UserManual
7430‐0808‐01Rev.B
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N3 Payload Contents
Byte
set
Off
Name Form
at
Scaling Units Description
20 eVel I2 512/2^16 m/s GPSEastvelocity
22 dVel I2 512/2^16 m/s GPSDownvelocity
24 longitudeGPS I4 2*pi/2^32
)
(360°/2^32
Radians
(°)
GPSLongitude
28 latitudeGPS I4 2*pi/2^32
)
(360°/2^32
Rad

ians
(°)
GPSLatitude
32 altitudeGPS I2* 2^14/2^16 m GPSaltitude(‐100,16284)
34 GPSheading I2 2*pi/2^16
6)
(360°/2^1
Radians
(°)
headinganglefromGPS
measurement
36 xRateTemp I2 200/2^16 degC Xratesensortemperature
38 UTCTimeOfDay U4  Milli‐sec UTCtimeoftheday
42 UTCDayofYear U2   
44 UTCYear U2   
46 BITstatus U2 — — MasterBITandStatus

NOTE:IfnoGPSavailabletheUTCtimesecondandUTCmsarethetimesincetheunitispoweredon.Theyearand
daywillbesetto0.
NavDataPacket4
Table53N4DataPacket
NavData(‘N4’=0x4E34)
Preamble PacketType Length Payload Termination
0x5555 0x4E34 0x2C <N4payload> <CRC(U2)>
ThispacketisidenticaltotheNAV1packetwiththeexceptionofhavinga4‐byteoutputofaltitude,whichallowsfor
altitudesgreaterthan8192meters.Thispacketcontainsnavigationdataandselectedsensordatascaledinmost
casestoasigned2^162’scomplementnumber.Datainvolvingangularmeasurementsincludethefactorpiinthe
scalinga
ndcanbeinterpretedineitherradiansordegrees.
•
Angles:scaledtoarangeof(‐pi,+pi)or(‐180degto+180deg)
• (‐630deg/secto+630deg/sec)
Angularrates:scaledtorangeof3.5*(‐pi,+pi)or
•
Accelerometers:scaledtoarangeof(‐10,+10)g
• °C
Temperature:scaledtoarangeof(‐100,+100)
•
Velocities:scaledtoarangeof(‐256,256)m/s
•
Altitude:scaledtoaresolutionof0.125meters
• Longitudeandlatitude:scaledtoarangeof(‐pi,pi)or(‐180degto+180deg)