Automatic Identification System

Leica Marine GPS unveiled the first fully integrated GPS/DGPS/AIS shipboard system during a press conference at the NorShipping marine exhibition in Oslo. The new MX 420 system meets the IMO carriage requirements for Automatic Identification Systems (AIS). It incorporates a high-accuracy MX 421 GPS/DGPS receiver and an IMO-compliant AIS transponder system, with a combined control and display unit. Optionally, the MX 420 AIS can be interfaced with an already installed GPS or DGPS receiver on board instead of the MX 421.

The MX 421 is a type-approved high-precision GPS/DGPS "smart antenna". It is the first marine GPS product to use the new Silicon Germanium (SiGe) receiver chip, which was developed jointly by Leica and IBM. In field trials, the MX 421 has consistently achieved positioning accuracies of under three meters RMS (root mean square) in an autonomous, non-differential mode. When used with the built-in dual-channel DGPS beacon receiver, the MX 421 yields accuracies of under one meter RMS. The MX 421 DGPS beacon receiver includes an H-field antenna for superior signal reception and interference rejection, and has been designed to meet all existing and projected IMO carriage requirements for GPS and DGPS.

The heart of the MX 420 system is its Control and Display Unit (CDU), which controls all GPS, DGPS and AIS functions. The CDU collects inputs from the ship's gyrocompass, speed log and other sensors, organizes the data for transmission through the AIS transponder unit and collects and displays AIS data from all other stations. It also interfaces with the ship's ECDIS, ARPA, VDR and other systems. The CDU keypad is used for entering static and voyage-related data for AIS reports, as well as system setup and all GPS/DGPS functions.