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GYROCOMPAS1

The gyrocompas1 protocol consists of three messages: HEHDT (heading), PHTHR (roll and pitch) and PHINF (status).

Data:

  • Heading

  • Pitch, roll

  • Status

Format:

$HEHDT,xxx.xx,T*hh<CR><LF>

Gyrocompas1 protocol description (HEHDT)

FIELD N.

FIELD

DESCRIPTION

UNIT

DATA TYPE

NOTE

0

HEHDT

identifier

-

string

Telegram identifier.

1

xxx.xx

heading

[deg]

DBL

Heading increase in clockwise direction.

xxx.xx : 'xxx' is the integer part of the heading represented by three digits in range [0,359], '.’ is decimal separator and 'xx’ is the fractional part of the heading represented by two positive digits in range [0,99].

2

T

'T' character for heading

-

string

Identifier for heading.

3

hh

checksum

-

-

XOR of characters between $ and *.

4

<CR><LF>

Termination characters

-

-


Format:

$PHTRH,xxx.xx,a,yyy.yy,b*hh<CR><LF>

Gyrocompas1 protocol description (PHTRH)

FIELD N.

FIELD

DESCRIPTION

UNIT

DATA TYPE

NOTE

0

PHTRH




Telegram identifier.

1

xxx.xx

pitch

[deg]

DBL

xxx.xx : 'xxx' is the integer part of the pitch represented by three positive digits in range [0,179], '.’ is decimal separator and 'xx’ is the fractional part of the pitch represented by two positive digits in range [0,99].

2

a

pitch sign

-

string

If 'M': Bow up (positive).

If 'P': Bow down (negative).

3

yyy.yy

roll

[deg]

DBL

yyy.yy: 'yyy' is the integer part of the roll represented by three positive digits in range [0,179], '.’ is decimal separator and 'yy’ is the fractional part of the roll represented by two positive digits in range [0,99].

4

b

roll sign

-

string

If 'B': Port down (positive).

If 'T': port up (negative).

5

hh

checksum

-

-

XOR of characters between $ and *

4

<CR><LF>

Termination characters

-

-


Format:

$PHINF,ssssssss*hh<CR><LF>

Gyrocompas1 protocol description (PHINF)

FIELD N.

FIELD

DESCRIPTION

UNIT

DATA TYPE

NOTE

0

ssssssss

status code

-

HEX


1

hh

checksum

-

-

XOR of characters between $ and *

4

<CR><LF>

Termination characters

-

-


Example:

HEHDT frame with raw example data is listed below.

$HEHDT,231.57,T*29<CR><LF>

Field 0

Field 1

Field 2

Field 3

$HEHDT

231.57

T

29

Decoded values:

  • Heading

    • Raw value: 231.57, decoded heading angle: 231.57 degrees


PHTRO frame with raw example data is listed below.

$PHTRO,0.16,P,0.29,B*79<CR><LF>

Field 0

Field 1

Field 2

Field 3

Field 4

Field 5

$PHTRO

0.16

P

0.29

B

79

Decoded values:

  • Pitch

    • Raw value: 0.16, decoded pItch angle: -0.16 degrees (due to 'P').

  • Roll

    • Raw value: 0.29, decoded roll angle: 0.29 degrees (due to 'B').


PHINF frame with raw example data is listed below.

$PHINF,00000000*117<CR><LF>

Field 0

Field 1

Field 2

$PHINF

00000000

117

Decoded values:

  • Status code

    • Raw value: 00000000, decoded status code: 0.


Note

The reference frame for data (e.g., roll) is configurable in the gyrocompas1 protocol. Also, the data's location (e.g., MRU or MP1) is configurable.