Madden Maritime ECDIS : What happens when the GPS signal goes away?


#1

Madden Maritime ECDIS :What happens when the GPS signal goes away?

Good article at Madden Maritime with regards to vulnerability of GPS. Some mariners tend to conflate ECDIS with GPS but they are very much two separate things.

I have the mates plot terrestrial directly on the ECDIS, Madden mentions that celestial LOPs can be done on ECDIS as well.


#2

I see they mention HDOP. That’s a measure of the best possible fix quality available at that moment based on the geometry of the satellites being received (relative to each other and to the vessel). I mention this because it took me some effort to find it out some years ago.


#3

it will get interesting at the next 11 year sun spot cycle if the earth gets hit by a solar storm???


#4

I assume the mandatory fit spec for gps will be changed to allow multi constellations to be received. That covers a few potential issues.


#5

Inertial navigation should be a required input into ECDIS. That should trap GPS errors, and provide an onboard back up that is not at risk for remote systems failure, jamming, or spoofing.


#6

yes but only good for about 10 minutes, lots of the DP rigs in some parts of Brazil and West Coast Africa have INS integrated, if really is a great idea, should be the basis for every DP system


#7

It would be nice to have a back-up for the GPS but failing that the answer is to make sure the mates are familiar with getting bearing / ranges off the radar or visual and plotting them on the ECIDS. It’s actually quicker and more convenient then the paper chart.

Also the use of parallel indexing with radar. Everyone seems to think the sextant skills will be needed but if GPS is lost mid-ocean that’s a trivial problem compared to if the ship is in Singapore Straits at 18 kts four abreast at night in a rain squall.

Mid-ocean the track to be adjusted to be more DR/radar friendly if needed, for example overcast weather.


#8

i would be hoping they havnt got the autopilot connected to the ecdis so heading changes are manual?


#9

Yeah, the thinking seems to be it won’t fail.

Once you get the E/R manned, the ship slowed down and in single file, another mate on the bridge and things sorted out it’s be OK but I’m thinking that initial transition is going to be rugged.


#10

gps on the autopilot is creating that scenario of someone spoofing the gps or any hiccup with it.
I know the 2 wires are there to connect them but no way would i allow that in my fleet ( or my yacht which had that ability way back in the 90’s)