Installation Alignment Packet

Installation Alignment Packet
Packet ID				185
Length				73
Read / Write				Read / Write
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 <add [3] jhere]	37	fp32	4	GNSS antenna offset X (m)¹
12 <add [3] jhere]	41	fp32	4	GNSS antenna offset Y (m)¹
13 <add [3] jhere]	45	fp32	4	GNSS antenna offset Z (m)
14	49	fp32	4	Odometer offset X (m)₂
15	53	fp32	4	Odometer offset Y (m)²
16	57	fp32	4	Odometer offset Z (m)²
17	61	fp32	4	External data offset X (m)³
18	65	fp32	4	External data offset Y (m)³
19	69	fp32	4	External data offset Z (m)³

¹Update to GNSS Antenna offset results in an update to fields:

Aiding Source Configuration Packet 1: #3 Internal GNSS PVT - Position Offset
Aiding Source Configuration Packet 1: #5 External GNSS PVT - Position Offset

²Update to Odometer offset results in an update to fields:

Aiding Source Configuration Packet 1: #8 External Odometer - Position Offset
Aiding Source Configuration Packet 2: #6 External DVL Data - Position Offset

³Update to External data offset results in an update to fields:

Aiding Source Configuration Packet 1: #7 External Position - Position Offset
Aiding Source Configuration Packet 1: #11 External Velocity - Position Offset
Aiding Source Configuration Packet 1: #12 External Position Velocity - Position Offset
Aiding Source Configuration Packet 1: #13 External Body Velocity - Position Offset
Aiding Source Configuration Packet 2: #3 Internal Depth Sensor - Position Offset
Aiding Source Configuration Packet 2: #4 External Subsonus - Position Offset
Aiding Source Configuration Packet 2: #9 External USBL Position Offset

Alignment DCM

The alignment DCM (Direction Cosine Matrix) is used to represent an alignment offset of Boreas from its standard alignment. A DCM is used rather than Euler angles for accuracy reasons. To convert Euler angles to DCM, 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)

DCM[1][2] = cos(pitch) * sin(roll)

DCM[2][0] = sin(heading) * sin(roll) + cos(heading) * sin(pitch) * cos(roll)

DCM[2][1] = -cos(heading) * sin(roll) + sin(heading) * sin(pitch) * cos(roll)

DCM[2][2] = cos(pitch) * cos(roll)