Moog Crossbow GNAV540 - Manual (Page 82)

Page 82
GNAV540 User Manual
7430‐0808‐01 Rev. B
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 and 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)