Installation Manual

89-041 Section 6 Issue 4 S6-1
6 - Serial interface communications protocols
As previously stated, the Transponder has seven RS-422 interfaces which are all available on
the Screw Terminal board:
• 3 sensor data input ports SEN1, SEN2 and SEN3
• 2 Bi-directional input/output ports MAIN and AUX/Pilot
• 1 Bi-directional input/output port RTCM
• 1 Bi-directional input/output port LR (Long Range)
Sensor data interface
The Sensor data input ports receive navigational data in NMEA–0183 format from the
connected sensors. The connected sensors can be a GNSS unit used for navigation, a
gyrocompass and a bottom track log. These data are processed in the UAIS unit and
transmitted as dynamic data. The data received by other stations over the VHF link form an
image of the sensor data. It is therefore vital that the sensor data are correct and that the port is
correctly configured.
The sensor ports of the UAIS Transponder understand the following IEC 61162 sentences. The
priority order of listing is left to right:
Latitude & Longitude: GNS, RMC, GGA, GLL
Speed Over Ground: VBW, RMC, VTG, OSD
Course Over Ground: RMC, VBW, VTG, OSD
Heading: HDT, OSD
Rate Of Turn: ROT, calculated from heading (HDT, OSD).
Navigational data must be received via the sensor ports within certain intervals; the maximum
intervals are listed in the table below. If NMEA sentences containing identical information arrive
at the sensor input ports, the UAIS Transponder will choose the information with the highest
priority level.
The built-in GNSS unit will under normal conditions only be used for TDMA slot timing. However
if no data are received from the external sensors, the built-in GNSS unit can be set to take over
automatically and supply navigational information for the VHF data link transmission. The
changeover between internal GNSS information use and external sensor information use
happens automatically, information received from the external sensors has priority and will
always be used when available.
List of messages received from sensors
Data type Max update
interval [s]
NMEA application Default parameter value
Date 3 RMC Year 2000, month. 0, day 0
UTC 3 GNS, RMC, GGA,
GLL
24:60:60
Lat, Lon 3 GNS, RMC, GGA,
GLL
91°00′00″ nl, 181°00′00″ wl
Datum 30 DTM Not defined
SOG,
COG
3 RMC, VBW, OSD
102.3, 360°
Altitude 3 GNS 4095
Heading 10 HDT 511
Turn rate 10 ROT -128
RAIM 10 GBS Ok