Navico Inc. HS35 User Manual

A valid USER MMSI must be entered into this radio before these AIS functions can be 
used. See section 5-1. 

The marine Automatic Identification System (AIS) is a location and vessel information 
reporting system. It allows vessels equipped with AIS to automatically and dynamically share 
and regularly update their position, speed, course and other information such as vessel 
identity with similarly equipped vessels. Position is derived from the Global Positioning 
System (GPS) and communication between vessels is by Very High Frequency (VHF) digital 
transmissions.

There are a number of types of AIS device as follows:

•  Class A transceivers. These are similar to class B transceivers, but they are designed to be 

fitted on large vessels such as cargo ships and large passenger vessels. Class A transceivers 

transmit at a higher VHF signal power than class B transceivers and therefore can be 

received by more distant vessels, and also transmit more frequently. Class A transceivers 

are mandatory on all vessels over 300 gross tonnes on international voyages and certain 

types of passenger vessels under the SOLAS regulations.

•  Class B transceivers. Similar to class A transceivers in many ways, but are normally lower 

cost due to the less stringent performance requirements. Class B transceivers transmit at 

a lower power and at a lower reporting rate than class A transceivers.

•  AIS base stations. AIS base stations are used by Vessel Traffic Systems to monitor and control 

the transmissions of AIS transceivers.

•  Aids to Navigation (AtoN) transceivers. AtoNs are transceivers mounted on buoys or other 

hazards to shipping which transmit details of their location to the surrounding vessels.

•  AIS receivers. AIS receivers will generally receive transmissions from class A transceivers, 

class B transceivers, AtoNs and AIS base stations but do not transmit any information about 

the vessel on which they are installed.

This radio contains an AIS receiver only function.

Defined transmit rates for Class A vessels shown below are provided for reference purposes 
only. The frequency of messages received will vary due to a number of factors including but 
not limited to such factors as antenna height, gain and signal interference.

•  Static information is either broadcast every 6 minutes, when data has been amended, or 

upon request.

•  Dynamic information is broadcast depending on speed and course alteration based on 

the following tables:

At anchor or moored

3 Minutes

0-14 knots

10 Seconds

0-14 knots and changing course

3 1/3 Seconds

14-23 knots

6 Seconds

14-23 knots and changing course

2 Seconds             

Ship faster than 23 knots

2 Seconds

Ship faster than 23 knots and changing course

2 Seconds

Class B Shipborne mobile equipment not moving 
faster than 2 Knots

3 Minutes

Class B Shipbome mobile equipment moving 2-14 
Knots

30 Seconds

Class B Shipbome mobile equipment moving 14-23 
Knots

15 Seconds

Class B Shipbome mobile equipment moving faster 
than 23 Knots

5 Seconds

Search and Rescue aircraft (airborne mobile 
equipment)

10 Seconds

Aids to Navigation

3 Minutes

AIS base station

10 Seconds

Source of information for above tables 1-1, 1-2: (ITU recommendations technical document: 
ITU-R M.1371-1)

Providing that other vessels with AIS transceivers installed are within radio range of your 
vessel, you should see their details appear on the AIS plotter screen. These details are also 
repeated on the NMEA ports for display on a compatible chartplotter / MFD.

Specific details of how to configure your chartplotter to make use of the AIS receiver features 
will be given in your chartplotter manual. If you are using charting software running on a PC, 
please refer to the instructions provided with your chartplotting software for details of how to 
configure it to display AIS information.

Simrad - RS35 Operation Instructions

Simrad - RS35 Operation Instructions

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