Glocom Gemini 128s
Gemini-128s is a dual-channel Inmarsat Fleet 55 ship earth station capable of low-rate telephony (secured and regular), 9.6 kbps fax, MPDS and high-speed ISDN data services up to 128 kbps. It has an automatic satellite tracking and antenna stabiliser that enable the terminal to operate under severe sea motions. The terminal functions under Inmarsat global area network (GAN) via Inmarsat 4th generation satellites for worldwide coverage. Gemini-128s dual-channel design provides convenience for users to operate two service modes simultaneously (e.g. voice and G4 fax; file transfer and teleconference, etc). Gemini-128s is also available for Inmarsat lease service under I-3 satellite network.
Typical applications
- Real time data reporting on vessel ECM (Engine Condition Monitoring) through MPDS
- Live video /studio for coastguard patrol operations
- High speed data download from off-shore oil drilling platform on geo-information
- Shipboard hub and crew calling on separate voice channels
Product uniqueness
- The world’s first dual channel, single-antenna F55 terminal with 128 kbps data capabilities
- Double bandwidth of regular Inmarsat F55 – at about the same physical dimension
- Simultaneous MPDS (always on) and circuit switched calls
- Can work under both Inmarsat 3rd and 4th generation satellites. Spot bema services will be near global (99% coverage) under 1 – 4 once all 3 satellites are in service
Service capabilities
The Gemini 128s provides all of the capabilities of two separate Inmarsat single channel F55 terminals in one physical unit. Each of the two channels may be used independently to make/receive voice or data calls or the two channels can be used together to make/receive 128 kbps data calls. Services provided by two channels in any combinations are:
Global Beam Services (total 2 channels in any combination)
- 2 channels of 4.8 kbps voice (Mini-M voice)
- 2 channels of 2.4 kbps secure voice/data (STU-III or STU-IIB)
Spot beam service (total 2 channels in any combination)
Voice
- 2 channels of 4.8 kbps voice (mini-M) voice
- 2 channels of 2.4 kbps secure voice/data (STU-III or STU-IIB)
- 2 channels of 64 kbps high quality speech
Data
- 2 channels of 64 kbps or combined 128 kbps data (UDI)
- 2 channels of 56 kbps data
MPDS
- 1 channel of 64 kbps packet data (shared)
Fax
- 1 channel of 9.6 kbps fax
Audio
- 1 channel of 3.1 kHz audio
System configuration
The two modules of Gemini-128s are connected by a coaxial cable carrying DC power and modulated data between ADU and BDU. Maximum distance separating ADU from BDU is 100 metres using LMR 400 type shielded cable. The system is powered by AC power (universal 110/220 VAC input) through BDU. ADU is bolt mounted to a mast or other structure above deck. BDU is usually mounted below deck with other navigation or telecommunications equipment. On the rear panel of BDU, an array of external ports is available for connecting user’s peripheral equipment (e.g. ISDN phone, video conference unit, fax machine and DTF dial phone etc).
Physical characteristics
Above deck unit (ADU)
- Housing: fibreglass radome outside dimensions: 720mm (diameter) x 700mm (H)
- Weight: 27g
- Mounting: bolt
- Components:
- Antenna: directional RHCP antenna with self-tracking stabilised platform
- Transceiver unit: PCB modules
- RF units: HPA diplexer, LNA
- Stabiliser: ACU and step motor
- Cable to BDE: RG-312 coaxial cable, type N connector
Below deck unit (BDU)
- Dimensions: 320 x 230 x 100mm (h x w x d)
- Weight: 4.7kg
- Components: Terminal Control Unit: PCB unit
- AC-DC converter
- SD card; SIM card
Radio frequency characteristics
- Transmit frequency: 1626.5 – 1660.5 MHz
- Receive frequency: 1525.0 – 1559.0 MHz
- Channel frequency spacing: 1.25 kHz steps
- G/T: -7 dB/K minimum
- EIRP: M4 HSD: 19 – 25 dBN in 2dB steps; Mini-M 8 – 14 dBW in 2 dB steps
External interfaces
- RJ-45 *1: ISDN NT1 S/T, ITUT, I.430, Euro-ISDN compliant
- RJ-11 *3: 2 for 4.8 kbps Mini-M voice with built-in DTMF tone detection
- DB-9 male *1: NMEA-0183 for GPS (auxiliary)
- DB-9 female *1 64 kbps shared channel MPDS
- USB *1 64 kbps shared channel MPDS
- Smart card *1: ISO 7816 compliant
- Mini DIN*1: System debug, RS-232
- SD card: Software downloaded
Environmental characteristics
- Ambient temperature
- Above Deck Equipment (ADU): -25 – +50C air temperature outside the radome
- Below Deck Equipment (BDU): 0 – +50C air temperature outside the equipment
- Solar radiation (ADU)
- Infra-red flux density of up to 500 Watts/m2
- Ultraviolet flux density of up to 54 Watts/m2
- Relative humidity: up to 95% at 40C
- Spray (ADU): Solid droplets from any direction
- Icing (ADU): up to 25mm of ice
- Precipitation (ADU): up to 100mm per hour
- Wind (ADU): normal operation with relative average wind velocity up to 100 knots
- AC power variations:
- Frequency: 50/60Hz ± 6%
- Voltage: AC110 – 220V ± 10%
Vibration
| Frequency range (Hz) | Peak Amplitude (mm) |
|---|---|
| 4 – 10 | 2.54 |
| 10 – 15 | 0.76 |
| 15 – 25 | 0.40 |
| 25 – 33 | 0.23 |
| Frequency range (Hz) | Peak Amplitude (mm) |
|---|---|
| 4 – 15 | 0.76 |
| 10 – 25 | 0.40 |
| 25 – 33 | 0.23 |
| 33 – 40 | 0.13 |
| 40 – 50 | 0.07 |
| Motion | Amplitude | Period | Maximum induced acceleration for ADU |
|---|---|---|---|
| Roll | ± 30 deg | 8s | 0.5g tangential |
| Pitch | ± 10 deg | 6s | 0.5g tangential |
| Yaw | ± 8g | 50s | |
| Surge | ± 0.2g | ||
| Sway | ± 0.2g | ||
| Heave | ± 0.5g | ||
| Turning rate | ± 6 deg/s | 1 deg/s |
Certifications
- Overall: meets or exceeds all specs in Inmarsat-M4 System Definition Manual
- CE EMC Directives (89/335/EEC per EN 300 339 V1.1.1)
Standard configuration
- Above Deck Unit (ADU) (1)
- Below Deck Unit (BDU) (1)
- ADE/BDE Coaxial Cable, C1 (25m)
- ADE bolt mounting unit kit (1)
Optional accessories
- Extra length ADU/BDU calbe (50m and 100m)
- STU-III interface option
- 9.6 kbps fax interface option
- Terminal adaptor (ISDN-USB or others)
Inmarsat Type Approval Certificate: 66GC50
For more information on the Gemini-128s or to discuss your requirements in more detail, please get in touch.