HRPT/AHRPT System > Marine Antenna

Dartcom 1.5m active-stabilised marine antenna installed on the oceanographic research vessel BAP Carrasco

Dartcom 1.5m active-stabilised marine antenna installed on the oceanographic research vessel BAP Carrasco
Dartcom 1.5m active-stabilised marine antenna installed on the oceanographic research vessel BAP Carrasco

Active-stabilised pedestal
Active-stabilised pedestal

Below-decks equipment rack
Below-decks equipment rack

1.5m active-stabilised marine antenna

This antenna is designed to track polar-orbiting satellites on moving vessels using a state-of-the-art active-stabilised X-Y pedestal to compensate for pitch, roll and yaw. It has continuous axis movement to eliminate cable wrap problems without slip-rings or rotary joints. Together with the pedestal’s high speed and accuracy this ensures no “cone of silence” (data loss at high elevations).

The antenna has a 0.35 F/D ratio and 26dBiC gain (S-band 28dBiC) to achieve a system G/T of better than 4.3dBK at 1.7GHz and 6.7dB/K at 2.252GHz, both at 5° elevation, and a bit error rate of better than 1:106 from 2° elevation.

The reflector is a 1.5m diameter prime focus aluminium parabolic dish finished in light grey paint. An integrated feed/downconverter (IFD) is mounted at the focal point in a hermetically sealed unit.

The dish and pedestal assembly is mounted inside a weather-tight glass fibre radome and base with access hatch.

The dish, pedestal assembly and antenna control unit (ACU) are mounted inside a weather-tight composite radome with a hatch in the base or side. The ACU provides fully automatic control of the pedestal with an advanced stabilisation algorithm. Full diagnostics and maintenance facilities are available via the ingest PC.

The equipment rack is located below decks and contains the receiver rack, ingest PC, UPS and network switch.

This antenna is CE certified and has been designed to meet or exceed military standard (MIL-STD) specifications.

Marine antenna specifications
Pedestal:  
    Stabilisation Active, with gyro sensors for pitch, roll and yaw rates
    Azimuth range No limit (continuous)
    Elevation range –10° to 190°
    Pitch rate ±15° in 8 seconds
    Roll rate ±30° in 8 seconds
    Yaw rate ±80° in 50 seconds
    Turn rate 10°/second
    Total weight 180kg approx
Radome:  
    Height 1.98m approx
    Diameter 1.96m approx
Environment:  
    Wind speeds 185km/h (100kt) operational
240km/h (130kt) survival
    Temperature –10°C to +70°C operational
(–40°C with optional heater)
    Design specifications:  
    EMI/RFI MIL-STD-461
    Vibration MIL-STD-167-1
    Shock MIL-STD-901
Power requirements:  
    Voltage 115/230V AC @ 50/60Hz
    Power consumption 1000VA typical
Integrated feed/downconverter specifications
Feed:  
    Beamwidth 3dB at 80°
10dB at 150°
    Gain +4.5dBi
    Polarisation Right-hand circular
Input filter:  
    Insertion loss 0.3dB maximum
    Bandwidth 120MHz maximum
Overall:  
    Noise figure 1.2dB typical
    Gain 60dB minimum
    Converted bandwidth 50MHz typical
    Input range 1682–1710MHz
    IF output 117–145MHz


Receiver Rack

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