I was trying to highlight if you could get a warning via any process, dont think you can..
your assuming a jump, what about a slow drift?
You have 4 scenarios to deal with in order from easy to hard:
- GPS is jammed, it just won’t work. Warnings will pop up, AIS obviously won’t work, etc. etc.
- GPS is radically spoofed, you suddenly are 100 miles away. That should be obvious to the crew, if not the equipment.
- GPS is very subtly spoofed, say you are northbound and move 10 yards east every few minutes. This one is harder to catch. I am not sure how easy that is to do.
- Extra Credit Annoyance: AIS targets that don’t actually exist pop up all over the place. This is not hard to do at all. Most people would probably just turn the AIS off.
1 Like
Way back in the 70’s the IBM integrated navigation system had a facility that would immediately expose spoofing but it was never adopted for ECDIS .
I’m still of the opinion that spoofing that puts a vessel in immediate danger should be obvious to a competent watch keeper using the equipment available on a modern vessel.
1 Like
As a random recreational sailor, here’s my take:
- I should have an idea of where I am at any given time, and where I expect to be in the future. If the screens show me elsewhere, I’m going to work out why.
- As someone mentioned up-thread, how often and how precisely I need to know my position is a function of how close I might be to danger.
Ignoring AIS for the moment, I would expect to be able to easily cross-check GPS with a radar overlay in coastal areas, or with a sextant in open ocean. My expectation is that I’m doing some form of position-verification at appropriate intervals. In general I like to take advantage of on-the-fly monitoring, e.g. if I’m going up the coast then even with a basic radar I can set a VRM to my desired distance off.
On the topic of autopilot, I almost always set it to steer a course rather than steer to a waypoint. So I don’t imagine it would be much affected by spoofing. It does occur to me that a satellite compass might be impacted by spoofing (although a satellite compass could possibly be a useful tool to detect it as well).
I am curious how much the position error estimate on the GPS jumps during spoofing. I do recall one time the number being quite high on my tablet, and indeed the position was quite off from where I estimated I should be (it had me in a TSS lane). It soon settled down, and I suspect it was more an issue with the tablet getting its wits together than anything else.
1 Like
autopilot set to waypoint , very scary or even more scary is follow track
METHODS OF NAVIGATION
To name them it is necessary to divide navigation sensors and systems in several broad ways, or methods, of navigating which are:
• Dead Reckoning (e.g. inertial navigation);
• Externally Dependent (e.g. GPS); and
• Database Matching (e.g. celestial navigation).
To envision these methods, imagine being blindfolded and moving to some
unknown area. If you kept track of your turns and distance travelled while
moving, you would be DEAD RECKONING .
The KING of dead reckoning is of course INS(inertial navigation system)
" Among dead reckoning systems, Inertial Navigation Systems (INS) are the most complete and also the most complex. They consist of multiple accelerometers and gyroscopes which continuously measure both linear acceleration and angular rotation rate in three dimensions. Starting from a given initial position, the INS updates the path followed by the user based on the motions sensed by the gyroscopes and accelerometers. During this process the velocity and attitude of the vehicle are also computed. "
If, while blindfolded, you shouted out, “Where am I?” and waited for bystanders to answer, you would be EXTERNALLY DEPEDENT. ( GPS ,Loran C, Decca, Omega, Tranist , other systems )
If you took your blindfold off and looked around, you
might be able to determine your location by recognizing various landmarks
and matching them to images in your memory - DATA BASE navigation.
I don’t like it. Setting the course and constantly checking your track keeps you in the loop and the boat won’t suddenly take off the wrong way if the GPS acts up.
I find my situational awareness way better in course mode than waypoint mode.
your track is made and recorded by what?
The Gent is still searching on google and AI what is not there .
3 days??? Wow.