WAYPOINT - ECDIS onboard: sizing up the options

01 Feb 2014 The Navigator

Dr Andy Norris, an active Fellow of The Nautical Institute and the Royal Institute of Navigation, looks at ECDIS and explains why it is very different from the car sat nav system

Although not often said directly, it is clear from comments made that some people really do believe that there is not a lot of difference between an ECDIS and a car’s sat nav. After all, they both show your current satellite position on an electronic chart, and both can display the proposed route ahead.
Of course, in reality, they are very different. Perhaps the most fundamental difference is that an ECDIS can still be used for safe navigation in the absence of satellite derived position – just try using a typical car’s sat nav without a satellite positioning input! Mind you, it’s surprising how many people actually think that ECDIS needs satellite positioning to be able to work at all. It certainly complicates things when that is not the case, but the lack of electronic position facilities similarly complicates working with paper charts.
Of course, another big issue with the standard vehicle sat nav is the small size of the display. That said, however, they are now getting surprisingly large in some top-end cars and can be equivalent to tablet computer dimensions in some cases. In fact, the use of tablet-based electronic charts is already permitted in the cockpits of civil airliners within the United States. So, is this the way that maritime should also be going? Some marine portable pilot units (PPUs) are already using such technology.

One size does not fit all…
We need to look at the differences between the uses for aviation, marine and pilotage, let alone car sat navs. In the very first issue of The Navigator, I pointed out that an airline pilot is fundamentally a monitoring navigator, following pre-agreed routes and mostly at altitudes assigned by air traffic controllers. For these reasons, the necessary chart information is relatively lacking in detail compared to that of a marine chart suitable for a ‘navigating’ navigator. Also, cockpit space on an airliner is limited, favouring a smaller display.
Marine pilots have to carry onboard their specialist equipment, and so a small PPU is essential. Importantly, once onboard, the pilot also has access to the vessel’s own charting facilities, whether ECDIS or paper charts.
The larger display size of an ECDIS is essential to maintain adequate area awareness. In fact, an often quoted and valid negative point about ECDIS is that they are still small when compared to an equivalent paper chart. In the future, we will inevitably see larger displays introduced. They will have better resolution too, similar to that given by paper charts – and by quality tablet computers.

ECDIS into the future
Exactly where such large displays should be positioned on a bridge will be interesting to see. In fact, the use of a specialist display seems to somewhat go against the still-developing concept of multifunction workstations, which can be configured to show any information, including ECDIS. It will certainly be fascinating to see what happens on new bridges over the next decade.
What does seem to be highly useful, and could happen very quickly in comparison, is the adoption of tablet computers on the bridge to show useful navigation information when operating away from the main conning position, such as on the bridge wings. It is easy to foresee that both ENC and radar information could be made affordably available as a tablet app on a modern bridge set-up.
When adopted, we would always need to bear in mind the secondary nature of such information displays. In no way would they be a replacement for the formal use of ECDIS and radar, but they could be highly useful to aid the final navigational decisions that will still need to be verified at the main full-sized displays.

In the future, we will inevitably see larger displays introduced. They will have better resolution too, similar to that given by paper charts – and by quality tablet computers

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