I would think this wouldn't just be limited to flights but also to shipping. Chartplotters are an awfully handy thing but paper charts are probably immune to these attacks.
GPS is only useful/useable in a civilized environment. Such an environment is NEVER guaranteed. Plan accordingly. Sadly it appears the US military hasn't learned this lesson...some businesses haven't learned it either.
Yes, you can maintain a DR plot, and you can add current vectors to give an Estimated Position, but you still need a fix to start plotting from. If you can't establish when/where your GPS fixes became unreliable, you're stuck until you close the land and can measure bearings from known points. (Or get radar ranges from known points.)
Get an accurate chronometer, an accurate compass, learn to use a sextant to take sun shots, get a copy of the Nautical Almanac, and make sure you can accurately determine your speed (true wind calculations help here). Also, learn celestial navigation. When everything fails, you'll still be able to navigate generally where you want to be.
The magic means for the insurance gods is "ALL available means of prudent navigation." and let's be fair, the insurers are in charge.
I was just making the point last night that LORAN is more difficult to blanket jam, it being possible to emulate a transmitter station if needed by substituting it and even by adding daughter stations to the chain and throwing out a Notice to Mariners that there's a new LORAN transmitter in the area worth tuning in to, and can be adapted to signal hopping as well if needed. I was a late adopter to GPS when lobstering out in open water. I expected about 50' accuracy, but in areas where I'd linger it would drop to 10' with the repeatability improving with time.
It's a mind eff for young mariners because the plot doesn't require a grid line and intersecting signals, there is no need for LORAN to relate to LAT and LON, no need to limit the number of transmitters you're pulling TD's from, and in a pinch you can always get a running fix if there's just one transmitter getting to you. If it's hard to plot a running fix using just one signal station, you can just turn for a minute and get a new fix.
My favorite captain to sail with, when he liked a brand new mate or a cadet from one of the academies, after dropping the pilot off at the south end of the Cape Cod Canal, and putting steering on the Iron Mike (gyropilot), would tell the person to take a good fix on the chart, and report when done. He would then walk around the bridge, and turn off all the the GPS's, turn off the chart plotter, turn off the AIS, GMDSS, NAVTEX, all bridge electronics except for one VHF radio and one radar, and say "You've got the paper charts, you've got a good AB, (Able seaman, a lookout) the gyro repeaters and the mag compass. Take us to Corpus Christi (or Houston), Use ALL means of getting fixes. If you lose confidence, turn in closer to shore and dip into the red zone of any handy lighthouse (many lighthouses will show red if you look at it from a direction that means you're standing somewhere unsafe), get a running fix and dip back out."
By this means, all junior mates learned how to navigate, and motivated Able Seaman like me learned the art of it too. When the radio operator came aboard twice a year to tinker with the electronics (radio operators being the child of a Geek Squad employee and a cable company installer), the captain would get an unhappy constipated look on his face, but he'd always have the radio operator test the dusty box that was the lookout's coffee cup holder, which was a radio direction finder.
Anyhow, on those trips, I learned the real art of navigating and the more senior watch officers brushed up on celestial navigation, which is still required. Technically, in fair weather every watch MUST have record of a position fix using a non-electronic means on an unlimited tonnage ship, which means 6 times a day. Generally this is just azimuths and amplitudes on a star or the sun to check the compasses for error, but 3 or 5-star fixes on every clear night watch were expected at some point.
9 comments:
You still need to plot a position on the paper chart, and if your only source of position data is GPS you're still stuck.
Bloke,
Heading and time elapsed should give you a decent Dead Reckoning. You miss tide, current, and wind but you do get yourself close. But that's just me.
- Ted
It's almost like it was a mistake to quit teaching stellar navigation...
Or to stop transmitting radio nav-aids.
GPS is only useful/useable in a civilized environment. Such an environment is NEVER guaranteed. Plan accordingly. Sadly it appears the US military hasn't learned this lesson...some businesses haven't learned it either.
Yes, you can maintain a DR plot, and you can add current vectors to give an Estimated Position, but you still need a fix to start plotting from. If you can't establish when/where your GPS fixes became unreliable, you're stuck until you close the land and can measure bearings from known points. (Or get radar ranges from known points.)
Never forget the Honda Point disaster when you cheer for DR:
https://en.wikipedia.org/wiki/Honda_Point_disaster
Getting rid of VORs (and Loran-C) was a dumb idea from the start.
Get an accurate chronometer, an accurate compass, learn to use a sextant to take sun shots, get a copy of the Nautical Almanac, and make sure you can accurately determine your speed (true wind calculations help here). Also, learn celestial navigation. When everything fails, you'll still be able to navigate generally where you want to be.
The magic means for the insurance gods is "ALL available means of prudent navigation." and let's be fair, the insurers are in charge.
I was just making the point last night that LORAN is more difficult to blanket jam, it being possible to emulate a transmitter station if needed by substituting it and even by adding daughter stations to the chain and throwing out a Notice to Mariners that there's a new LORAN transmitter in the area worth tuning in to, and can be adapted to signal hopping as well if needed. I was a late adopter to GPS when lobstering out in open water. I expected about 50' accuracy, but in areas where I'd linger it would drop to 10' with the repeatability improving with time.
It's a mind eff for young mariners because the plot doesn't require a grid line and intersecting signals, there is no need for LORAN to relate to LAT and LON, no need to limit the number of transmitters you're pulling TD's from, and in a pinch you can always get a running fix if there's just one transmitter getting to you. If it's hard to plot a running fix using just one signal station, you can just turn for a minute and get a new fix.
My favorite captain to sail with, when he liked a brand new mate or a cadet from one of the academies, after dropping the pilot off at the south end of the Cape Cod Canal, and putting steering on the Iron Mike (gyropilot), would tell the person to take a good fix on the chart, and report when done. He would then walk around the bridge, and turn off all the the GPS's, turn off the chart plotter, turn off the AIS, GMDSS, NAVTEX, all bridge electronics except for one VHF radio and one radar, and say "You've got the paper charts, you've got a good AB, (Able seaman, a lookout) the gyro repeaters and the mag compass. Take us to Corpus Christi (or Houston), Use ALL means of getting fixes. If you lose confidence, turn in closer to shore and dip into the red zone of any handy lighthouse (many lighthouses will show red if you look at it from a direction that means you're standing somewhere unsafe), get a running fix and dip back out."
By this means, all junior mates learned how to navigate, and motivated Able Seaman like me learned the art of it too. When the radio operator came aboard twice a year to tinker with the electronics (radio operators being the child of a Geek Squad employee and a cable company installer), the captain would get an unhappy constipated look on his face, but he'd always have the radio operator test the dusty box that was the lookout's coffee cup holder, which was a radio direction finder.
Anyhow, on those trips, I learned the real art of navigating and the more senior watch officers brushed up on celestial navigation, which is still required. Technically, in fair weather every watch MUST have record of a position fix using a non-electronic means on an unlimited tonnage ship, which means 6 times a day. Generally this is just azimuths and amplitudes on a star or the sun to check the compasses for error, but 3 or 5-star fixes on every clear night watch were expected at some point.
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