1. PRINCIPLE OF NAVTEX SYSTEM

1.3Message Format

For automatic identification of messages, each message starts with nine control characters, called “Header codes”.

The first five characters are always “ZCZC_“ and common to all messages. This part is used for message synchronization. The latter four characters are designed as B1, B2, B3 and B4 indicate origin, category and serial number of the message.

Character B1 is the identification letter of the Navtex station “A” thru “Z”. Character B2 indicates the type of message. “A” thru “Z”, as listed below. Character B3 and B4 indicate the serial number of the message. The serial numbers are counted up from “01” to “99”, and starts from “01” again. Number “00” is specially reserved for important emergency messages.

The end of each message is indicated by “NNNN” (four successive N’s). General message format is summarized below.

 

 

 

Header code

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

main message

 

NNNN

 

ZCZC B1 B2 B3 B4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Start code

 

 

 

 

 

 

 

 

Main message

Termination code

 

(sync)

 

 

 

 

 

Serial number

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

"00":

Emergency message

 

 

 

 

 

 

 

 

 

 

"01" - "99": Normal message

 

 

 

 

 

 

 

 

 

Type of message

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

"A" - "Z"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(See the list below.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Station ID

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

"A" - "Z"

 

 

 

 

 

 

[Type of message (category)]

 

 

 

 

 

 

 

A:

Navigational warning

I:

Spare

 

 

 

 

B:

Meteorological warning

J:

SATNAV message

C:

Ice report

K:

Other electronic navigational aid

 

 

 

 

 

 

 

 

 

 

 

 

 

 

system message

D:

Search and rescue information/pirate

L:

 

attack warnings

 

E:

Meteorological forecast

V to Y

F:

Pilot message

 

G:

AIS

 

H:

LORAN message

Z:

Navigational warning (addition to “A”)

Special services allocation by the NAVTEX Co-ordinating Panel

QRU (no message on hand)

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Page 14
Image 14
Furuno NX-700A manual Message Format, Nnnn

NX-700A specifications

The Furuno NX-700A is an advanced navigation system designed specifically for professional mariners and commercial vessels. Known for its robust performance and precision, it integrates state-of-the-art technology to enhance safety and efficiency at sea. One of the most notable features of the NX-700A is its dual-channel frequency system, which allows for improved target detection and tracking capabilities. This dual-channel operation ensures that the system can differentiate between multiple targets, reducing the risk of collisions and enhancing situational awareness.

Another significant aspect of the NX-700A is its high-resolution display. The system is equipped with a large LCD screen that provides clear and detailed graphical representations of surrounding waters, including navigational aids and potential hazards. The intuitive interface allows for easy operation even in challenging conditions, ensuring that crews can concentrate on their primary task: safe navigation.

Further enhancing the usability of the NX-700A is its advanced GPS functionality. The system employs multi-GNSS (Global Navigation Satellite System) technology, enabling it to obtain accurate position fixes from various satellite constellations, including GPS, GLONASS, and BeiDou. This capability ensures that mariners receive reliable positioning data regardless of their location, which is crucial during navigation in remote areas.

The NX-700A also features robust connectivity options, including NMEA 2000 and NMEA 0183 support. This allows the system to interface seamlessly with other onboard equipment, such as autopilots, engine monitoring systems, and electronic chart plotters. Such integration enhances operational efficiency and aids in maintaining a central command point for navigation.

Marine safety is further bolstered with the NX-700A's built-in man-overboard function, which provides rapid and precise positioning information in emergency situations. The system can also store critical navigational data, which can be accessed quickly during emergencies, contributing to enhanced safety protocols on board.

In summary, the Furuno NX-700A is a sophisticated navigation solution that combines high-resolution displays, advanced GPS technology, dual-channel frequency systems, and robust connectivity. Whether used in fishing vessels, cargo ships, or pleasure yachts, the NX-700A stands out as a reliable tool for enhancing maritime safety and navigation efficiency. With its user-friendly interface and essential features, it embodies the modern requirements of marine navigation technology.