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MRU
Demo Program Manual
Inertial Labs, Inc
TM
Address:
39959 Catoctin Ridge Street, Paeonian Springs, VA 20129 U.S.A.
Tel: +1 (703) 880-4222, Fax: +1 (703) 935-8377
Website:
www.inertiallabs.com
105
Table C.4
. The message payload at MRU Quaternion Data format
Byte
number
0-7
8 – 13
14 –
19
20 –
25
26 –
27
28 –
29
30-31 32 – 33 34 – 35
Parameter
Lk0, Lk1,
Lk2, Lk3
GyroX,
GyroY,
GyroZ
AccX,
AccY,
AccZ
MagX,
MagY,
MagZ
Reser
ved
Reser
ved
USW Vinp Temper
Length
4
2 byte
sword
3
2 byte
sword
3
2 byte
sword
3
2 byte
sword
2 byte
sword
2 byte
sword
2 byte
word
2 byte
word
2 byte
sword
Note
Quaternion of
orientation *10000
Angular
rates,
deg/s
*KG
Accele-
rations,
g*KA
Magne
tic
fields,
nT/10
Supply
voltage,
VDC*
100
Temper
ature,
ºC*10
Table C.4 (continued)
Byte
number
36 – 39 40 – 41 42 – 43
44 – 45
46 – 47 48 – 49 50 – 51 52 – 55
Parameter Heave Surge Sway
Heave
velocity
Surge
velocity
Sway
velocity
P_bar
or
Hs
H_bar
Length
4 byte
integer
2 byte
sword
2 byte
sword
2 byte
sword
2 byte
sword
2 byte
sword
2 byte
word
4 byte
integer
Note
m*100 m*100 m*100 m/s*100 m/s*100 m/s*100
Pa/2
or
m*100
m*100
Notes
1.
See detailed description for correct relationship between orientation angles and
quaternion in the MRU ICD, “APPENDIX D. Forms of the Inertial Labs
TM
MRU
orientation presentation”.
2.
Values of KG, KA are scale factors depending on gyro and accelerometer range:
Gyro range, deg/sec 250 or 300 450 or 500 1000 2000
KG
100
50
20
10
Accelerometer range, g
2
6
8
10
15
KA
10000 5000 4000
2000 2000
3.
Angular rates, linear accelerations and magnetic fields are in the carrier object axes
(X is lateral axis, Y is longitudinal axis, Z is vertical axis). The MRU orientation
relative to the carrier object axes is set by alignment angles (see Appendix E.
Variants of the Inertial Labs
TM
MRU mounting relative to the object axes).
4.
USW is unit status word (see Appendix D. The Unit Status Word definition, for
details).
5.
Vinp is input voltage of the MRU.
6.
Temper is averaged temperature in 3 gyros.