Installation Alignment Packet; Alignment Dcm - Advanced Navigation GNSS Compass Reference Manual

10.11.4

Installation Alignment Packet

Packet ID
Length
Field # Bytes Data
Offset Type
1 0 u8
2 1 fp32
3 5 fp32
4 9 fp32
5 13 fp32
6 17 fp32
7 21 fp32
8 25 fp32
9 29 fp32
10 33 fp32
11 37 fp32
12 41 fp32
13 45 fp32
14 49 fp32
15 53 fp32
16 57 fp32
17 61 fp32
18 65 fp32
19 69 fp32
Table 97: Installation alignment packet
10.11.4.1

Alignment DCM

The alignment DCM (direction cosine matrix) is used to represent an alignment offset of GNSS
Compass 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)
DCM[1][1] = cos(heading) * cos(roll) + sin(heading) * sin(pitch) * sin(roll)
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Installation Alignment Packet
Size
1
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
GNSS Compass Reference Manual
Page 77 of 85
Version 1.1
13/01/2021
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Description
Permanent
Alignment DCM[0][0]
Alignment DCM[0][1]
Alignment DCM[0][2]
Alignment DCM[1][0]
Alignment DCM[1][1]
Alignment DCM[1][2]
Alignment DCM[2][0]
Alignment DCM[2][1]
Alignment DCM[2][2]
GNSS antenna offset X (m)
GNSS antenna offset Y (m)
GNSS antenna offset Z (m)
Odometer offset X (m)
Odometer offset Y (m)
Odometer offset Z (m)
External data offset X (m)
External data offset Y (m)
External data offset Z (m)