SubscribeReporters delivering live coverage from areas of conflict around the world have become standard features in today's news programs.
Equipped with satellite based transmission equipment, they report their impressions and experiences and document local incidents on camera. This up-to-date coverage is imperative for increasing TV viewer ratings, and hence revenues for the news stations. But, are these reports always objective? Caution is advised, since emotionally loaded reports help to drive high ratings.
A country’s political and military command sending soldiers on out-of-area missions needs up to date, but also objective and comprehensive information on the local situation. Since material provided by commercial media organisations cannot always be relied upon to provide information with which they can accurately assess the situation, the decision makers are evermore reliant on footage gathered by their own staff for situational appraisal, damage assessment and conservation of evidence.
Within the German Armed Forces, this task is carried out by the soldiers in the Mission Video Unit of the “Operative Information Centre” in Mayen. Equipped with photo and video cameras, electronic editing and cutting applications and a satellite terminal, they fulfil their missions out-of-area and transmit their picture and sound reports via satellite directly back to the Command Centre in Germany.
The following article describes the technical equipment and infrastructure that is required to transmit the Mission Video Unit’s out-of-area reports via satellite and terrestrial networks.
System overview
The Mission Video Units are required to operate within the mission areas predefined by the German Armed Forces. Transmissions are made out of these mission areas to Germany. The central receiving station is the anchor station of the German Armed Forces in Gerolstein, which receives the signals from the transportable uplink stations and processes them for terrestrial distribution within Germany. Through the German Armed Forces digital distribution network (DigÜnBw) and the respective local area networks, the information is forwarded to the command centres in Bonn and Potsdam.
The end-to-end transmission system mainly consists of the following four subsystems:
- Video recording and video editing on location,
- Uplink station,
- Downlink entity and
- Video transmission, video reception and video editing in Germany
The interaction between the subsystems is shown in Fig. 1
Fig. 1: System Overview
The footage taken by the subsystem “Video recording and video editing on location” is transmitted via the uplink station, over satellite and on to the German Armed Forces’ anchor station in Gerolstein. The transmission can, depending on the location, take place in C-band or Ku-band.
The downlink path is located in the operations room of the anchor station in Gerolstein and is connected to the receive components via intermediate frequency. The downlink stream is connected to the DigÜnBw through a cross-connect device (CCSTM). Through the DigÜnBw network, the data is transmitted to the Ministry of Defence in Bonn (BMVg), as well as to the Mission Command Centre (EinsFüKdo) in Geltow. There, the incoming signal is received by another CCSTM and forwarded to the respective centres via HDSL modems. The video and audio data are evaluated here using the locally installed subsystem “Video reception and video editing”.
Video recording and video editing on location
The Mission Video Unit has three video cameras available for shooting their video coverage. Two identical cameras, including night visibility units, serve the mobile camera team in documenting onto video cassette. By using two independent cameras, it is possible to simultaneously shoot details as well as the big picture. Should one camera become defective, it can quickly be exchanged by another, thus ensuring operational availability at all times.
Static events such as press conferences can be filmed with a third camera in real-time. In this case, video / audio data are transmitted directly (without editing) through the uplink station to Germany.
For preliminary footage editing, a portable editing case is carried (see Fig. 2). After editing, the end product can be stored on a video cassette. A video recorder is available to play-out the miniDV or DVCPRO format video footage.
Fig. 2: Editing Case
Transportable uplink stations for global transmission
The uplink station is the transmission device for the locally recorded or in real-time transmitted video footage. It is designed as a FlyAway terminal and consists of three parts:
- DVB case
- Antenna unit
- Power supply
The coverage is encrypted and transmitted at a data rate of 4 Mbps. The encryption concept relies on a freely selectable alphanumeric “session key”, which is entered into the DVB encoder and decoder before the mission. The encryption method is compliant with the requirements of the DVB Standard Common Scrambling. All FlyAway terminals are Intelsat and Eutelsat compliant, making worldwide utilisation possible.
DVB case
The portable Digital Video Broadcasting (DVB) case shown in Fig. 3 is waterproof to IP 54 and contains a 19” rack. The front and back covers are removable. Stored in the case is a DVB encoder, two DVB modulators with integrated upconverters for use in C-band or Ku-band, two patch panels to connect the video equipment and the antenna unit, as well as the HPA controller. In addition, it contains the power supply for the monitoring LNBs. All equipment remains in the case during operation. The antenna unit is connected via coaxial cable.
Fig. 3: DVB Case
Antenna unit
The antenna unit amplifies the modulated uplink signal and beams it to the satellite. For the transmission of video footage to the satellite there are two antenna unit options available. The FlyAway Terminal MFT2400 is a multi-band terminal which can be operated worldwide and can transmit both in C and Ku-band according to available satellite capacity. The smaller MFT1900 sends in Ku-band and is currently suitable for most of the German Armed Forces mission areas. Its compact design makes it easier to deploy.
MFT2400 – 2.4 meter multi-band FlyAway
Figure 4 shows the 2.4 meter FlyAway system in operational mode. The DVB case and the UPS can be clearly seen. The antenna reflector is divided into 9 segments and can be dismantled to ensure high transportability.
The antenna unit consists of:
- Segmented antenna reflector,
- Antenna mount, lightening protection rod and grounding kit,
- Feed arm and feed system
- Low Noise Block Converter (LNB),
- High Power Amplifier (HPA),
- RF, control and power supply cables
Fig. 4: MFT2400
The standard 2.4 m antenna can be used in the C and Ku-bands. Exchanging the feed system enables the antenna to transmit in X-band as well. Antenna positioning is supported by LNBs, which convert the satellite receive signal from C or Ku-band into broadband L-band. The reflector is made of carbon fibre; the reflector support, feed arm and antenna mount are made of aluminium. A high antenna system stability can hence be achieved at a relatively low weight. Outstanding performance characteristics for mobile missions, even under difficult environmental conditions, can be guaranteed long-term. Antenna shipping takes place in 9 transportation cases and meets all requirements for air transportation and for various means of land transportation.
By use of quick–release clamps and other captive fixing devices, antenna assembly can be carried out within a very short time. The antenna is set up on a cantilevered tripod, which provides facilities for anchoring at the installation location. Antenna positioning is continuously adjustable; vertically from 0° to 90° and horizontally to 180°. The polarization is adjustable to 95°.
The entire MFT2400 system is stowed and transported in 19 cases with a total weight of less than 700 kg and a transport volume of around 4m². Set-up time by a two-person crew is less than 45 minutes. Depending on the linkbudget and error correction settings, an uplink data rate of up to 45 Mbps can be achieved with the base band equipment provided. The C-band uplink Equivalent Isotropic Radiated Power (EIRP) amounts to a maximum of 66 dBW, and Ku-band to a maximum of 73 dBW.
In case of a malfunction of the transmit station or when interference signals affect the operation of adjacent channels on the satellite transponder, it is imperative that the uplink station operator be informed. Since there is no return channel implemented from the anchor station to the MFT2400 FlyAway, there needs to be an alternative method of reaching the Mission Video Unit. This requirement is met by using a Mini-M Inmarsat terminal. It features telephone, fax and data transmission and uses the same technique as the digital GSM networks. The Inmarsat Mini-M terminal allows a transmission rate of up to 4.8 kbps for voice. Data and fax are transmitted with a rate of 2.4 kbps. The user can be reached globally.
MFT1900 – 1.9 meter Ku-band FlyAway
Three smaller antenna units of type MFT1900 (see Fig. 5) form an extension to the original system. These diamond-shaped antennas have a reflector diagonal of 1.9 meters. The basic FlyAway configuration is supplied with a feed system for Ku-band operation and can be refitted for operation in C and X-band if required. The MFT1900 is not only more compact and much lighter than the multi-band terminal MFT2400, it is also supplied per default with a return channel. A multiplexer for voice transmission (to which an analogue telephone or fax can be connected) is integrated into the system. Telephone connections are made over Gerolstein, where the multiplexer’s receiver sits. Via this so-called “Order Wire” function, a channel is established which makes communication between the Mission Video Unit and Germany, indeed, the rest of the world, possible.
Fig. 5: MFT1900
Power supply
The system power supply needs to provide electrical power for the mobile HPA, DVB modulators and MPEG encoder components as well as heating and ventilation for the same. A reserve supply for measuring devices and other small equipment is also required.
The self-sufficient and continuous power supply of the uplink station during a mission is ensured by a power generator set. The generator itself is driven by a diesel engine.
In case of an outage of the local electricity network or the generator, the batteries of an uninterruptible power supply (UPS) take over to ensure the uplink station’s continual operation for a further 20 minutes. That is usually time enough to send a video report via satellite. If there is an under or over voltage, the UPS will compensate for the error. The UPS is built into a portable housing with a 19” rack and is certified waterproof to IP 54. The UPS guarantees a switch of energy source without delay.
Downlink station and terrestrial connection
The anchor station in Gerolstein, with its existing C-band and Ku-band outdoor units and downlink entity, make up the downlink station. The downlink’s component assembly is integrated in a mobile 19” rack. The connection to the anchor station’s receiver chain is realised at the 70 MHz intermediate frequency level.
The incoming data stream with a rate of 4,096 Mbps is divided into two 2,048 Mbps data streams with the help of an inverse multiplexer and then passed into the DigÜnBw. The connection to the DigÜnBW is realised through a CCSTM cross connect multiplexer.
To assess and monitor the quality of the received video signal, the anchor station in Gerolstein uses a video reception system consisting of a DVB demodulator, DVB decoder and a monitor.
Video reception and editing facilities
In the Ministry of Defence and the Mission Command Centre respectively, the DigÜnBW terminates at the CCSTM. From there the video signals are fed into the local area networks over two E1 cables, using HDSL-modems. Once the signals have reached the command centres, they are multiplexed, decrypted and decoded. The video signal is decoupled over various signal standard options, and the audio signal is fed out through a separate channel. Both signals can be further processed in the cutting room.
Forecast
For the video coverage of out-of-area missions, the German Armed Forces is dependent on civilian satellite operators from whom they rent satellite capacity. C-band satellites with a global footprint enable a worldwide deployment of the Mission Video Units, demands, however, a higher transmission power and a larger antenna diameter for the uplink station. The MFT2400 meets these high demands, and is therefore suitable for global missions. With the MFT1900 the German Armed Forces has an additional, high-power mobile terminal with a small antenna, which can be deployed everywhere where a Ku-band footprint is available.
The German Armed Forces currently plans an extension of its satellite communication capabilities within the SATCOMBw Step 2 programme. In the future it will command its own satellite capacity and thus become independent of other satellite operators. Through the Mission Video Units, equipped and networked as described above, the German Armed Forces is already making use of a modern, high-performing system for video reporting which can be smoothly integrated into the SATCOMBw Step 2 programme.
