Gnss Antenna Installation Antenna Location

MX535 UAIS Transponder Unit

Technical & Installation Manual

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3.5.2GNSS Antenna Installation

Antenna Location

The GNSS antenna must be installed where it has a clear view of the sky, so that it accesses the horizon freely through 360°, with a vertical observation of 5 to 90 degrees above the horizon. Small diameter obstructions, such as masts and booms, do not seriously impair signal reception, but such objects must not eclipse more than a few degrees of any given bearing.

The antenna must be located at least three meters away from, and out of the transmitting beam of high-power transmitters (S-Band Radar and/or Inmarsat systems). This includes the ship’s own AIS VHF antenna, if it is designed and installed separately.

If a DGNSS system is included or connected to the AIS system, the installation of the antenna should be undertaken in accordance with IEC 61108-4, Edition 1.

Cabling

To achieve optimum performance, the gain of the antenna pre-amplifier should match the cable attenuation. The resulting installation gain (pre-amplifier gain - cable attenuation) should be within 0 to 10 dB.

RG214 at GPS attenuation per meter of app. 0.35 dB/m (45m = 15.75dB) GPS frequency app. 1.2GHz

The coaxial cable between the antenna and the AIS ship borne station connector should be routed directly, in order to reduce electromagnetic interference. The cable should not be installed close to high-power lines, such as radar or radio-transmitter lines, or near the AIS VHF antenna cable. A space of one meter or more is recommended in order to avoid degradation due to RF-coupling. Crossing of antenna cables should take place at 90 degrees, to minimise magnetic field coupling.

Antenna Layout

The position of the VHF und GNSS – antennas must be added to the existing antenna layout of the vessel.

Power Supply

The MX535 transponder must be supplied from the emergency power source. A further requirement is to connect AIS to the reserve power source of the GMDSS. A new battery capacity calculation must then be undertaken.

Following documents are needed for the installation approval of the classification

•Antenna Layout (arrangement)

•Battery Calculation

•Connection / Block – Diagram with locations

•Type Approval Certificate