Every day, thousands of nautical vessels traverse our oceans, and heavily utilize satellite communications for many of their essential functions. The functions of satellite services to these vessels range from crew members communicating with family, monitoring infrastructure, production, weather conditions, and safety measures. The importance of these satellite-based services cannot be emphasized enough, and any disruption or lack of service would have a serious effect on both the safety and comfort of a vessel and its crew.
The satellite operator does a considerable amount of work keeping the satellite spectrum free of interference, which mostly goes unnoticed by the maritime industry, and leads many to assume the topic of satellite interference isn’t a discussion-worthy topic for this particular industry. In this sense, interference largely entails a significant degradation in service quality, inaccurate or partially available monitoring systems, with some cases involving a complete loss of some (or all) services.
In the event interference does occur, it’s often seriously disruptive but also dangerous, considering how important those services rely on satellite networks. Whenever nautical vessels travel in between regions, satellite terminals installed onboard must change from one satellite beam to another. This process is called repointing, and is essential to these crafts if they want to ensure continued coverage. Some satellite terminals are programmed to do this automatically, but in some cases, require manual intervention. During this particular point of transition, another facet is introduced—human error. This further bolsters chances of incorrect alignment, which apparently is almost too often the case when error arises.
When interference is caused by coms-on-the-move (COTM) service (designed for moving vessels, vehicles, or similar mobile uses), its differences between that of a fixed service are distinct. Envision the rolling action of a sea or military vessel crossing rugged terrain, during which the ship’s satellite terminal becomes subject to constant jarring, highly random movements, which means they’re rarely ever immobile. This makes pinpoint accuracy incredibly essential to assure a satellite’s continuous pointing accuracy, which in turn keeps the service locked.
The barrier to ensuring quality accuracy often comes in the form of poor-quality equipment. The margin for error within the maritime space is so low that antenna pointing must be impeccable. Even when taking the ship operator’s best efforts into consideration, an incorrectly-designed terminal, antenna, or degree of curvature on the dish being out by just a few millimeters can cause the satellite beam to incorrectly align with the point on the antenna, essentially losing the battle before it even begins.
Since COTM terminal locations are constantly on the move, this can be challenging for satellite operators trying to identify an interfering transmitter’s source. Geolocation has been a successful tool in reducing time to resolution for fixed terminal interference, essentially measuring the signal received by adjacent satellites to calculate the interfering carrier’s rough location.
New innovative technologies like drones, are making interference tracking easier when the antenna is moving, and the mere fact of the antenna being mobile helps increase the process’ accuracy. For crewmembers onboard these vessels to work out if their equipment is causing issues in the first place, it’s often difficult to determine if the interference is originating elsewhere. A lot of time may pass before one of these incidents are even reported to the operator, even after the issue has been acknowledged.
Resolving one incident of interference (even after the problem has been acknowledged) still takes time, and any amount needed to rectify an issue like this can disrupt a vessel’s operations. Taking the difficulty of solving maritime satellite interference when it strikes, the most practical way of mitigating these effects is by preventing them from happening in the first place. Therefore, terminal accuracy is essential to reducing effects to avoid these incidents. It’s paramount to maintaining the correct antenna alignments, and if vessel operators fail to use high-quality equipment, they’re fighitng a losing battle that hasn’t even begun.
Filed Under: Aerospace + defense