Setting up blockage zones correctly can reduce downtime, while smart terminals will be needed for new LEO constellations
Outages in satellite communications need to be prevented, ensuring continuity of operations and connectivity for crew. Loss of connectivity could cut critical voice calls, result in downtime to online applications and delay information being relayed to shore managers.
VSAT connections become critical as shipping adopts digitalisation, while outages could lead to vessel downtime or communications automatically switching to expensive back-up systems.
Service outages are untypical, but they can occur if the line of sight between the ship and the satellite is blocked, for example by the vessel’s own structures. According to Cobham Satcom senior director for global market strategy and development Matt Galston, around 85% of service outages reported can ultimately be retraced to errors made during installation.
“Of these errors, a significant majority relate to improper initial set-up of blockage zones,” he tells Maritime Digitalisation & Communications. Installation engineers can minimise the risk of outages by correctly setting up blockages zones.
With a Cobham Satcom Sailor, VSAT engineers can use a one-time set-up configuration during installation to account for blockages due to ship structures. “Owners no longer need to experience failures as the system proactively recommends how to optimise onboard set-up,” says Mr Galston.
Installers can select a wide setting as it is a safer bet than aiming for precision measurements. “If an installer defines blockage settings too narrowly, a satellite antenna believes it should see the satellite when in fact a legitimate blockage exists, resulting in lost connectivity,” Mr Galston explains.
“The user may go to the antenna controller for a quick look and see the antenna is not in a designated blockage zone, but still has no signal.” If there is no intelligence in this controlling system, there could be prolonged periods of communications outages.
“When a vessel is on the right compass heading relative to the satellite, this condition could go on for days,” says Mr Galston. Lost connectivity leads to questions why the antenna is not receiving signal. “Which then kicks off a process of diagnosis,” he continues. “Often leading to expensive shipboard interventions only to determine the root cause was human versus equipment failure.”
If an installer adds some margin to the blockage setting, there is less likelihood of prolonged blockages to VSAT communications. But, there are other issues to consider. “With the artificially large blockage zone, users simply get moved over to the L-band back-up sooner than needed,” says Mr Galston. This leads to additional expense or a significant drop in connectivity bandwidth for operations and communications.
Cobham Satcom introduced a blockage mapping feature to its Sailor VSAT antenna to eliminate these challenges for installers, vessel operators and onboard crew. This is increasingly important if service providers shift from procuring network capacity by the MHz to offering managed Mbps services as more cost-effective ways to service diverse customer needs.
“In the managed service model, operators may choose to shift traffic from one satellite to another at will to help load-balance their network,” says Mr Galston. This switching may result in an antenna following a command from the network operations centre (NOC) to acquire a satellite it cannot see due to blockage. “If that blockage was unaccounted for at installation, there is no way of understanding the failure from the NOC and confusion continues to drive unexpected costs,” Mr Galston says.
Non-geostationary challenges
This becomes more critical as the choice of maritime of satellite communications is extended through low Earth orbit (LEO) satellite constellations being commissioned.
“Not only will there be more satellites, but more continuous switching between them,” says Mr Galston. VSAT terminals need to be intelligent enough to know whether switching to the next satellite will be possible or not as vessels’ manoeuvre.
“This level of intelligence is essential to making the entire non-geostationary orbit satellite concept work on ships at sea,” says Mr Galston. Communications terminal will need to manage a high quantity of look angle permutations because an onboard antenna could have 10-20, or more than 100, available satellites in view.
Horizon Mask
Terminals will need intelligence to prevent Horizon Mask, a new challenge that comes with vessels using LEO satellites. Geostationary satellites are fixed in one orbital position, whereas LEO satellites are constantly moving. The precise position and time where and when these satellites will appear on the horizon can be calculated.
“What we do not know on board a ship is what may be in the way,” says Mr Galston. A vessel’s line of sight to this satellite could be blocked by geography, another ship or its own structure.
“There is no way to plan for this during installation,” says Mr Galston. “The best approach is for the terminal itself to be smart enough to provide live feedback to a network management system regarding what it will encounter next, so that the system can better plan in real-time.”
Cobham Satcom has been developing smart terminal technology over the past 12-18 months. “Certain projects employing our core technology in rather unorthodox use-cases have provided measurable insights on the interaction between terminal and network,” says Mr Galston. “Especially when that network is made up of unpredictably moving objects operating at extremely high and therefore precise frequencies.”
Cobham Satcom is ready for LEO communications and has demonstrated live tracking on two of the first new LEO satellites using its Sailor and Sea Tel ranges.
Snapshot CV
Matt Galston has worked in the maritime satellite communications sector since 2009 with roles at Geoeye and Intellian Technologies before joining Cobham Satcom in October 2017 as senior director for global market strategy and development.
Dual-band HTS antenna unveiled
KVH Industries has unveiled an antenna that enables ships to use high-intensity Ku-band from high throughput satellites (HTS) and widebeam C-band for communications, without installing a 2-m diameter antenna.
KVH’s TracPhone V11-HTS maritime antenna connects to geostationary satellites in both Ku-band and C-band with a 1-m diameter reflector. KVH chief executive Martin Kits van Heyningen says ships can access data speeds of up to 20 Mbps on the downlink and 3 Mbps on the uplink using this antenna.
TracPhone V11-HTS can automatically switch between bands using KVH’s mini-VSAT Broadband HTS network. It connects to an Integrated CommBox Modem (ICM) that includes a high-throughput modem, voice over IP adapter, CommBox network management software, and built-in wifi and Ethernet connection. The ICM also receives onboard news, entertainment, and operations content sent via KVH’s IP-MobileCast delivery service.
There are two VSAT channels. The high-speed channel is suitable for video applications, telemedicine, web browsing, and allocated crew usage. The unlimited-use channel is suitable for data transfers, email, software updates, automated file transmission and weather updates. It has a maximum bandwidth of 8 Mbps downlink and 2 Mbps uplink.
KVH also introduced HTS versions of its antennas in 2018, including a 60-cm diameter, Ku-band TracPhone V7-HTS and 37-cm diameter, Ku-band TracPhone V3-HTS.
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