Kongsberg Seapath 320, Installation Manual, Page: 122 / 152

Seapath 320
106 M300-62/rev.2
Checksum is calculated as a 16-bit Block Cyclic Redundancy Check of all bytes
between, but not including the Header and Checksum fields. The CRC algorithm is
described in a separate section. Time is divided in an integer seconds part and a
fractional second part. The integer seconds part of time is counted from 1970-01-01
UTC time, ignoring leap seconds. Latitude is positive north of the Equator. Longitude is
positive east of Greenwich. Height is above the ellipsoid. Heave is positive down. Roll
is positive with port side up. Pitch is positive with bow up.
The status word consists of 16 single bit flags numbered from 0 to 15, where 0 is the
least significant bit. A 1 value (true) means:
Bit no. Interpretation
0 Reduced horizontal position and velocity performance
1 Invalid horizontal position and velocity data
2 Reduced heave and vertical velocity performance
3 Invalid heave and vertical velocity data
4 Reduced roll and pitch performance
5 Invalid roll and pitch data
6 Reduced heading performance
7 Invalid heading data
The remaining bits in the status word are reserved for future expansion.
A.14 PFreeHeave format 24
This PFreeHeave™ format consists of a fixed-length message using 1-, 2- and 4-byte
signed and unsigned integers. The signed integers are represented as two-complement
numbers. For the multi-byte elements, the most significant byte is transmitted first. The
total number of bytes is 13.
The PFreeHeave output is delayed by a few minutes due to processing. The time fields
contain time of validity for the data.
Format:
Element Scaling Format Bytes Value
Header Unsigned 1 AA Hex
Header Unsigned 1 52 Hex
Time, seconds Seconds Integer 4
Time, fraction of second 0.0001 second Unsigned 2 0 to 9999
Heave Centimetres Integer 2