Installation Manual

TECHNICAL NOTE 3

DP message types

Introduction

The Radascan distinguishes between two operating modes; (a) single target/prism, and (b)

multiple target operation which can affect the type of data sent to the DP feed. However,

independent of this operation mode different DP feed message types can be selected from a

range of formats. The DP message update rate is 1 Hz.

Each format name is followed by the corresponding selection value that can be used in a

bitwise combination with other selection values (registry key:

DpFedAllowSelection) to define

which DP feed formats are available for selection by the normal DP operator. Typically this

should be set to only a single value corresponding to the DP system the sensor is connected

to.

The default DP feed selection value for normal operators is 0x0007 corresponding to the

NMEA0183R, NMEA0183P and ASCII17 formats. In engineer mode all formats with

selection values below 0x00FF are available.

NMEA0183R Format (0x0001)

A 42 character string:

$RLS,±AAA.AA,±BBB.BB,S1,XXX.XXX,S2,HHHH*CC<CR><LF>

• $RLS message header

• AAA.AA resolved raw position in A axis [metres]

• BBB.BB resolved raw position in B axis [metres]

• S1 status of position data in A and B axis, A – available; V – void

• XXX.XXX resolved bearing of vessel with respect to A axis [degrees]

• S2 status of bearing data, A – available; V – void

• HHHH status word in hexadecimal. Up to 16 bits defined by Guidance Navigation in a

separate specifications document

• CC computed checksum in hex

• <CR> Carriage return (ASCII 0D hex)

• <LF> Line feed (ASCII 0A hex)

Note: when the reflectors are installed on a fixed platform and their co-ordinates are entered

in Northings and Eastings, AAA.AA and BBB.BB will also be in Northings and Eastings and

XXX.XXX will be true vessel heading.

NMEA0183P Format (0x0002)