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Motus Reference Manual
Page 133 of 146
Version 1.1
29/11/2019
16.10.4 Installation Alignment Packet
Installation Alignment Packet
Packet ID 185
Length 73
Field
#
Bytes
Offset
Data
Type
Size Description
1 0 u8 1 Permanent
2 1 fp32 4 Alignment DCM[0][0]
3 5 fp32 4 Alignment DCM[0][1]
4 9 fp32 4 Alignment DCM[0][2]
5 13 fp32 4 Alignment DCM[1][0]
6 17 fp32 4 Alignment DCM[1][1]
7 21 fp32 4 Alignment DCM[1][2]
8 25 fp32 4 Alignment DCM[2][0]
9 29 fp32 4 Alignment DCM[2][1]
10 33 fp32 4 Alignment DCM[2][2]
11 37 fp32 4 GNSS antenna offset X (m)
12 41 fp32 4 GNSS antenna offset Y (m)
13 45 fp32 4 GNSS antenna offset Z (m)
14 49 fp32 4 Odometer offset X (m)
15 53 fp32 4 Odometer offset Y (m)
16 57 fp32 4 Odometer offset Z (m)
17 61 fp32 4 External data offset X (m)
18 65 fp32 4 External data offset Y (m)
19 69 fp32 4 External data offset Z (m)
Table 96: Installation alignment packet
16.10.4.1 Alignment DCM
The alignment DCM (direction cosine matrix) is used to represent an alignment offset
of Motus from it's standard alignment. A DCM is used rather than euler angles for
accuracy reasons. To convert euler angles to DCM please use the formula below with
angles in radians.
DCM[0][0] = cos(heading) * cos(pitch)
DCM[0][1] = sin(heading) * cos(pitch)
DCM[0][2] = -sin(pitch)
DCM[1][0] = -sin(heading) * cos(roll) + cos(heading) * sin(pitch) * sin(roll)