NORSUB7b

The NORSUB7b protocol is a proprietary communication standard with an NMEA-based format, designed to store the data listed below.

Data:

Roll, pitch, heading
Surge, sway, heave
Roll rate, pitch rate, yaw rate
Surge velocity, sway velocity, heave velocity
x acceleration, y acceleration, z acceleration
x period, y period, z period
x amplitude, y amplitude, z amplitude
Status A and B

Format:

$PNORSUB7B,T1,T2,roll,pitch,heading,surge,sway,heave,roll_rate,pitch_rate, yaw_rate,surge_vel,sway_vel, heave_vel,acc_x,acc_y,acc_z,T_x,T_y,T_z, A_x,A_y,A_z,status_A,status_B*CS<CR><LF>

NORSUB7b protocol description
FIELD N.	FIELD	DESCRIPTION	UNIT	TYPE	NOTE
0	$PNORSUB7B	identifier	-	string	Telegram identifier.
1	T1	time for valid measurement (internal clock)	[us]	uint32	Can store values from 0 to (2^32-1).
2	T2	delay from T1 to telegram is sent	[us]	uint32	Can store values from 0 to (2^32-1).
3	roll	roll angle	[deg]	DBL (%.4f)	Floating-point number with four decimal places.
4	pitch	pitch angle	[deg]	DBL (%.4f)	Floating-point number with four decimal places.
5	heading	heading angle	[deg]	DBL (%.4f)	Floating-point number with four decimal places. Range: [0.001 - 359.9999].
6	surge	surge	[m]	DBL (%.3f)	Floating-point number with three decimal places.
7	sway	sway	[m]	DBL (%.3f)	Floating-point number with three decimal places.
8	heave	heave	[m]	DBL (%.3f)	Floating-point number with three decimal places. Sign: Positive (+) when z-down.
9	roll_rate	roll rate	[deg/s]	DBL (%.3f)	Floating-point number with three decimal places.
10	pitch_rate	pitch rate	[deg/s]	DBL (%.3f)	Floating-point number with three decimal places.
11	yaw_rate	yaw rate	[deg/s]	DBL (%.3f)	Floating-point number with three decimal places.
12	surge_vel	surge velocity	[m/s]	DBL (%.3f)	Floating-point number with three decimal places.
13	sway_vel	sway velocity	[m/s]	DBL (%.3f)	Floating-point number with three decimal places.
14	heave_vel	heave velocity	[m/s]	DBL (%.3f)	Floating-point number with three decimal places. Sign: Positive (+) when z-down.
15	acc_x	acceleration x	[m/s²]	DBL (%.5f)	Floating-point number with five decimal places.
16	acc_y	acceleration y	[m/s²]	DBL (%.5f)	Floating-point number with five decimal places.
17	acc_z	acceleration z	[m/s²]	DBL (%.5f)	Floating-point number with five decimal places.
18	T_x	period x	[s]	DBL (%.2f)	Floating-point number with two decimal places.
19	T_y	period y	[s]	DBL (%.2f)	Floating-point number with two decimal places.
20	T_z	period z	[s]	DBL (%.2f)	Floating-point number with two decimal places.
21	A_x	amplitude x	[m]	DBL (%.2f)	Floating-point number with two decimal places.
22	A_y	amplitude y	[m]	DBL (%.2f)	Floating-point number with two decimal places.
23	A_z	amplitude z	[m]	DBL (%.2f)	Floating-point number with two decimal places.
24	status_A	status (first 2 bytes)	-	uint16	1: OK, 0: error. See health monitoring system for more details.
25	status_B	status (last 2 bytes)	-	uint16	1: OK, 0: error. See health monitoring system for more details.
26	CS	NMEA checksum	-	hex	XOR of characters between $ and *

Example:

NORSUB7B frame with raw example data is listed below.

$PNORSUB7B,1347578196,7939,-100.1028,0.8549,108.1722,0.029,0.021,-0.020, -0.069,-0.017,0.035,0.009,0.003,-0.003,0.00154,-0.00190,0.00302, 24.97, 25.00,23.02,2.01,1.02,0.85,1,1*5

Field 0	Field 1	Field 2	Field 3	Field 4	Field 5	Field 6	Field 7	Field 8	Field 9	Field 10	Field 11	Field 12	Field 13	Field 14	Field 15	Field 16	Field 17	Field 18	Field 19	Field 20	Field 21	Field 22	Field 23	Field 24	Field 25	Field 26
$PNORSUB7B	1347578196	7939	-100.1028	0.8549	108.1722	0.029	0.021	-0.020	-0.069	-0.017	0.035	0.009	0.003	-0.003	0.00154	-0.00190	0.00302	24.97	25.00	23.02	2.01	1.02	0.85	1	1	5

Decoded values:

T1
- Raw value: 1347578196, decoded time: seconds.
T2
- Raw value: 7566, decoded time: seconds.
roll
- Raw value: -100.1028, decoded roll angle: degrees.
pitch
- Raw value: 0.8549, decoded pitch angle: degrees.
heading
- Raw value: 108.1722, decoded heading angle: degrees.
surge
- Raw value: 0.029, decoded heave: m.
sway
- Raw value: 0.021, decoded heave: m.
heave
- Raw value: -0.020, decoded heave: m.
roll rate
- Raw value: -0.069, decoded roll rate: deg/s.
pitch rate
- Raw value: -0.017, decoded pitch rate: deg/s.
yaw rate
- Raw value: 0.035, decoded yaw rate: deg/s.
surge velocity
- Raw value: 0.009, decoded surge velocity: m/s.
sway velocity
- Raw value: 0.003, decoded surge velocity: m/s.
heave velocity
- Raw value: -0.003, decoded heave velocity: m/s.
acceleration x
- Raw value: 0.00154, decoded acc x: m/s².
acceleration y
- Raw value: -0.00190, decoded acc y: m/s².
acceleration z
- Raw value: 0.00302, decoded acc z: m/s².
period x
- Raw value: 24.97, decoded period x: s.
period y
- Raw value: 25.00, decoded period y: s.
period z
- Raw value: 23.02, decoded period z: s.
amplitude x
- Raw value: 2.01, decoded amplitude x: m.
amplitude y
- Raw value: 1.02, decoded amplitude x: m.
amplitude z
- Raw value: 0.85, decoded amplitude x: m.
status A
- Raw value: 1, decoded status: OK.
status B
- Raw value: 1, decoded status: OK.
checksum: 5
- Created from XOR operations of characters between $ and * in the example frame.

NORSUB7 / NORSUB7B / NORSUB8

NORSUB7, NORSUB7b and NORSUB8 are very similar in their structure. The important difference is that in the NORSUB7 and NORSUB7b protocol the surge, sway positions, velocities and accelerations are measured in the body frame, while in the NORSUB8 protocol they are measured in the heading frame. NORSUB7 and NORSUB8 contain the full STATUS word (n.24), while NORSUB7b contains the status split in to variables (n.24 and n.25): one containing the first two bytes, the other containing the last two.

Note

Unlike industry standards, the NORSUB7b protocol has a fixed reference frame for data (e.g., heave). However, the data's location (e.g., MRU or MP1) remains configurable.