appearing 50 miles off? On what ?
radar
Not lost, in this screen shot the narrator, presumably a deck officer, is showing on the display the actual position of the ship.
How does he know the actual position?
A glance at the radar would suffice for an experienced watch officer.
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damn hard when its all flat
havnt been there for 20 years but I remember it being very flat
Are there enough nav aids with radar reflectors?
Transited the Red Sea many times, it’s not an issue.
There’s a prominent feature NE’ly of the vessel where the coastline turns from N/S to E/W and the trackline serves as a LOP. Be a simple task to obtain an approximate position off the radar by eye.
Suppose this OOW has not forgotten what D. R. means.
Have never checked there the WiFi ranges and signal strength . This maybe to help estimate roughly his pos using mobile phone if D. R. skiils were completely forgotten.
Looks like estimating vsl position vs the last known and highly accurate is becoming a challenge for those relying solely on electronic aids to navigation.
I am slowly believing that the disappearance of the ship is causing more concern for peepshow addicts and shore side slackers glued to their AIS toys and applications, then to bridge teams affected by the sudden loss or jammed or spoofed GPS signal.
WHAT a drama???
Time to call SAR and issue mayday call.
Terrible
The problem is when the position is spoofed you need to realise and forget the GPS
You also need to realize every single thing on the AIS is suspect.
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Everything on ais is always suspect…
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For those currently at sea on the bridge, any standing orders to keep a DR going incase of spoofing?
ECDIS stores past track data.
11.5 Voyage recording
11.5.1 ECDIS should store and be able to reproduce certain minimum elements required to reconstruct the navigation and verify the official database used during the previous 12 hours. The following data should be recorded at one minute intervals:
- .1 to ensure a record of own ship’s past track: time, position, heading, and speed; and
- .2 to ensure a record of official data used: ENC source, edition, date, cell and update history.
11.5.2 In addition, ECDIS should record the complete track for the entire voyage, with time marks at intervals not exceeding 4 hours.The ECDIS is required to store “past track” data.
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when/how does it ignore gps and DR a track based on heading and speed?
Think @Meme.Lord could answer the question very well .
I remember only that on some ECDIS units in case of loss of GPS signals there was an alarm and a flashing banner informing the user the system switched to D.R. mode. Each manufacturer of ECDIS had it solved in different way and due to this fact alone - lack of COMONALITY ( unlike in airplanes) i had to go through this boring sessions of type specific training and then read the 800 pages manual on board to figure out things. But mates were very competent and good teachers too so the old man was catching up fast.
But with spoofing it seems to me there is no loss of GPS signal but rather a corruption of the signal . May be some smart ass algorythms nawadays can smell the difference between the genuine signal and corrupt and act accordingly , otherwise would expect the ECDIS voyage log corrupted as well if spoofed signal is not immediately or at least prompty detected by the user who must be vigilant and manually switch the ECDIS to D.R . mode.
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Back at the first post it explained how aircraft were having the INS error out because it thought the varying GPS positions meant the INS had gone bad.
Something is screwed here as I do not see sb answered my post - to find out i need to click my avatar.
While refering to your posts pls give a post number as there are many of your posts here with your flying experiences.
My question is what are you flying?? Jets or kites??
Ships move 10-20 kts . Which of your planes is flying with such speeds???
For DR I need speed and course plus some other items i will not discuss here. I can put these two values manually giving data derived from last good positions within a certain time frame. Speed input i may get from speed log or doppler log - i think they are not spoofed. Heading from the magnetic compass or past positions on the same heading and there is something You may not know .
A good ,well trained and experienced sea navigator can make position and keep D.R-econing from his DICK!!! .
Before GPS, Transit satellite, Omega, Decca, Loran C we were dead reckoning for days sometimes and did not end up in Las Vegas or North pole.
If you master these skills you do not give a shit about spoofing as long as you carefully monitor and double check your electronic toys. If you do not then it is your problem which is not my problem.
Spoofing is a problem for taxi drivers calling themselves navigators and having all their knowledge concentrated in their thumb or index fingers.
You need a hell of a lot more to be a merchant ships navigator .
Homework for You .
Lat 15 deg north .You are sailng at 045 deg true. Your speed through the water is 12 kts. No currents , no wind no effing earthquakes.
Calculate latitude change in 1 hr 42 minutes. What would be your gyro error at your calculated lattitude. Compare the final error with the innitial and tell me how it will influence your DR position after 3 hrs of sailing on the same course and speed. ?
Impress me with your flying skill.
Some DP vessels have INS to fill in where GPS fails or jumps.
Spoofing a slow error makes it very difficult to realise and then how far back do you go to start your DR assuming no radar targets?
You missed the point! If your nav device - whatever it is - has multiple inputs and they stop agreeing with each other, one of them is wrong! This is obvious. What is not always obvious is WHICH one. What if your spoofed GPS moves you 1/4 mile east every hour? Is the ECDIS going to decide on its own to revert to DR? Are you? How obvious is it which one is wrong?
Any halfway competent pilot of ships or airplanes should be able to get around without GPS, but doing so knowingly is very different than dealing with spoofing and disruption.