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Posted

Is inertial nav common outside the military?  With the advances in accelerometers and such, maybe garmin could add an INAV unit to their gps and alert if the diff is too big.

Posted

Thinking about this some....

 

While it's possible, I'm not sure if aircraft would have to worry much. The GPS antenna is usually on the top of the plane, which ought to make spoofing a LOT more difficult (the attacker would have to be airborne). Also, and probably most importantly, the planes that would be likely targets are up in the flight levels where they're on radar, right? "United 342.... where are you going?"

Posted

Inertial nav is common on airliners , They all pretty much have it (laser gyros) and they are unbelievably accurate , I have been told that they can fly thousands of miles and land within about a hundred feet of where they are supposed to be......They are very expensive , and they work by shooting light into a gas.....

Posted

How about that WASS aproach?

 

My point is FAA wants to put every egg in the GPS basket. GPS signals can be screwed with. With my old Rocket the auto pilot followed the LORAN, my eyes followed the pink line on the Garmin hand held and to stay involved I cross checked with a KNS 80 RNAV using VOR/DME. 3 ways to Christmas I knew where I was. If the FAA gets their way that one legged stool could fall over and kill someone.

 

Take the RNAV (GPS) X RWY 24 into CRQ. Brings you down to 500' between a 600' and a 900' tower into an airport surrounded by 400' towers. A couple hundred feet off line and it could get difficult.

Posted

Inertial nav is common on airliners , They all pretty much have it (laser gyros) and they are unbelievably accurate , I have been told that they can fly thousands of miles and land within about a hundred feet of where they are supposed to be......They are very expensive , and they work by shooting light into a gas.....

Mems chips do the same thing. Our company is almost done developing an inexpensive inertial system for tractors. Like all inertial nav systems, very accurate over short periods of time, just like the airline systems, as more time/distance passes, becomes less and less accurate. Even with a laser ring gyro, after 3000 miles you'd lose a lot more than hundred feet, more like miles. The system cross checks and reestablishes coordinates at all opportunities. 

Posted

How about that WASS aproach?

My point is FAA wants to put every egg in the GPS basket. GPS signals can be screwed with. With my old Rocket the auto pilot followed the LORAN, my eyes followed the pink line on the Garmin hand held and to stay involved I cross checked with a KNS 80 RNAV using VOR/DME. 3 ways to Christmas I knew where I was. If the FAA gets their way that one legged stool could fall over and kill someone.

Take the RNAV (GPS) X RWY 24 into CRQ. Brings you down to 500' between a 600' and a 900' tower into an airport surrounded by 400' towers. A couple hundred feet off line and it could get difficult.

All signals / transmissions can be screwed with. Remember 40 degree tacan lock-offs? GPS is an extremely weak signal- below the threshold of atmospheric noise actually, hence the susceptibility to spoofing. There are anti-spoofing modules for GPS, though... Just another gadget we'll all have to buy....
Posted

I do agree putting all of your eggs in the GPS basket is foolish, I don't think the FAA will decommission all of the VORs.  I'm hoping there will be a subset maintained to mitigate the solar flare event.  :)

Posted

Flying in IMC is probably behind me and IFR is now, for me, the hoary acronym for “I Follow Roads; Rivers; Railroads” or whatever. Thus the integrity of GPS is no longer of great concern while winging about in my venerable Moonrod as that contemporary celestial contrivance is but a colorful gadget with so many gimmicky features. The compromise of GPS IS, however, precisely why I still drag out a sextant from time to time to gaze upon various heavenly bodies, practice sight reductions using a rotation of HO 229, 249 and NAO tables and then plotting LOP’s for a fix or getting a rough fix from an LAN sight should I ever find myself in need of direction upon a less gaseous expanse. I also try to get a bit of practice on “lunars” in the event it turns out the NSA has a chip in my digital watch and it has to go over the side. Never hurts to have a backup; though I’ll leave the sextant at home while flying and stick to those roads and rivers and merely back that up with a colorful gadget.

Posted

Flying in IMC is probably behind me and IFR is now, for me, the hoary acronym “I Follow Roads; Rivers; Railroads” or whatever. Thus the integrity of GPS is no longer of great concern while winging about in my venerable Moonrod as that contemporary celestial contrivance is but a colorful gadget with so many gimmicky features. The compromise of GPS IS, however, precisely why I still drag out a sextant from time to time to gaze upon various heavenly bodies, then to practice sight reductions using a rotation of HO 229, 249 and NAO tables and then plotting LOP’s for a fix or getting a rough fix from an LAN sight should I ever find myself in need of direction upon a less gaseous expanse. I also try to get a bit of practice on “lunars” in the event it turns out the NSA has a chip in my digital watch and it has to go over the side. Never hurts to have a backup; though I’ll leave the sextant at home while flying and stick to those roads and rivers and merely back that up with a colorful gadget.

 

Amelia Earhart got lost despite her navigators use of celestial navigation.

 

Does anyone know when celestial navigation went away?  Didn't even some of the 1960s era jets have little window ports to allow for the navigator to have a peek at the skies?

Posted

Air Force navigators were shooting celestial well into the 80's at least, and F-4's were utilizing inertial nav systems into the '90's.

If GPS gets turned off, is hacked, or otherwise is unavailable, 'some' will still use VOR, DME, ADF, dead reckoning...

40 grand of glass and deteriorated basic navigation skills will ground many. Hope it never happens, but....

Posted
Amelia Earhart got lost despite her navigators use of celestial navigation. Does anyone know when celestial navigation went away? Didn't even some of the 1960s era jets have little window ports to allow for the navigator to have a peek at the skies?
I saw bubbles on Flying Tigers 747's in the late 80's, not sure what the last series of planes to have them put in were. There was last I checked one DPE left who could do the rating as it has been one I had interest in getting just for the neato factor but didn't really pursue more than idle checking. I always am putting in VOR's and cross referencing position on the chart when flying not so much out of fear of GPS going out but the GPS breaking. Plus kills the boredom and helps keep me sharp.
Posted

I saw bubbles on Flying Tigers 747's in the late 80's, not sure what the last series of planes to have them put in were. There was last I checked one DPE left who could do the rating as it has been one I had interest in getting just for the neato factor but didn't really pursue more than idle checking. I always am putting in VOR's and cross referencing position on the chart when flying not so much out of fear of GPS going out but the GPS breaking. Plus kills the boredom and helps keep me sharp.

 

I vaguely remember some of the big commercial jets with the bubbles but I cannot specifically remember when I stopped seeing that.

 

I also on some flights do the VORs just for practice even if I am navigating by GPS as primary - but I do it only sometimes.  Still a lot more than nothing.

 

The most unbelievable but true navigation story I ever heard was on NPR about 2 years ago about the DC3s flying through the notches in the Andes - still today.  I am forgetting the exact altitudes, but I think they were like 14,000 foot cruise flight to fly between 17,000ft peaks and over the notch.  No VORs or any navigational reference whatsoever.  So in IMC what they do is timed turns by whisky compass.  Can you imagine?!! 240 seconds at bearing 330 on the whisky then right bearing 330 for 300 seconds then begin a 500fpm descent....  It even works... most of the time.

Posted
The most unbelievable but true navigation story I ever heard was on NPR about 2 years ago about the DC3s flying through the notches in the Andes - still today. I am forgetting the exact altitudes, but I think they were like 14,000 foot cruise flight to fly between 17,000ft peaks and over the notch. No VORs or any navigational reference whatsoever. So in IMC what they do is timed turns by whisky compass. Can you imagine?!! 240 seconds at bearing 330 on the whisky then right bearing 330 for 300 seconds then begin a 500fpm descent.... It even works... most of the time.
Give me a stopwatch and a map, and I'll fly the Alps in a plane with no windows.......(Good movie)

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