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GPS - Trust / Don't Trust

And how many airlines are looking for Ex-Soviet fighter pilots to fly their passengers around??? The navigational equivalent to a bow and arrow would be a Sextant. Which for some reason is still used by Air Navs. Satellites can fall from the sky, but that big piece of iron floating inside the earth... well when it fails it just won't matter.
 
Petard said:
Agreed, and vital in doing a common sense check I'd say
"Trusting" ones' instruments without a common sense check, usually by using  hard copy map, can cause your mileage to unexpectedly vary.

Even though I have a GPS for my car, I always do a map recce. It's a certain source of amusement for my wife, and wonderment for my civilian friends.

I suppose the wise thing to do is to never trust a single source of information.
 
ModlrMike said:
Even though I have a GPS for my car, I always do a map recce.

Mike,

And I think you've hit a perfect point there.  I'm as much of a GPS believer as a person can be, but still not silly enough to rely entirely on it.

The key fault with the civilian versions is that if a person only cares about how far until their next turn, they risk not being able to visualize where they actually are on the ground.  Numerous times I have entered an address on my Garmin Nuvi only to get there and have it be nothing at all like what it's supposed to be, but due to understanding what roads are where I can find it.

A person who doesn't do that map recce and doesn't have a built in compass is just going to stop at the side of the road and cry, or have to start making cellphone calls and embarrassing himself.
 
Petamocto said:
I agree that a map is the basic building block though, and that is the one item that is critical.  If you have a map and navigation fundamentals you don't really need anything else because you understand what direction you're going, you can read the contours/roads, and you can measure distance.

After you have the map and fundamentals though, IMO a compass was last millennium's tool.  That doesn't mean it has no use any more than saying you don't need a knife anymore, but I do not see a compass as mandatory before moving on to a GPS. 

Navigating in close complex terrain, especially thick forest or jungle, where GPS signals may be attenuated to the point they're not useable, and there is no line of sight to see much of any contours or landmarks, I'd say a compass is very useful.
And for supported arm call for fire a compass is a very easy thing to use to get a a bearing to adjust off of
 
But what you are discussing is a very specific arc of employment, and yes I still carry my compass for just such an occasion (or sitting in a trench and wanting a static bearing).

That is the same as having a knife for doing something and a gun for doing something else.
 
Tango18A said:
Which for some reason is still used by Air Navs.

Stellar navigation is no longer taught at the school in Winnipeg and has not been for years. GPS and INS.........
 
Simple truth is never trust a single source for any information needed to carry out a task.

Many moons ago, there was a picture on the walls of the DC/FF school in Halifax of one of the big ferries that cross the English Channel high and dry on the beaches near Calais. Now the mariners that run those things are like bus drivers: they know their route by heart. So how did it happen? Simply, the input wire that connected the GPS feed to the electronic map got loose - and the map automatically went into dead reckoning mode. It just forgot to compensate for the five knots currents found in the area. By the time the captain felt a "weird" vibration, made his way to the bridge, looked at the radar screen and figured out where he really was, it was too late.

That is why naval captains insist to this day: never two fixes in a row using the same source in coastal waters - check each source against the others all the time. And why the pilots on warships still try to put in a good astro-fix once a day in mid ocean - just to feel comfortable with the GPS data.
 
Petard said:
Navigating in close complex terrain, especially thick forest or jungle, where GPS signals may be attenuated to the point they're not useable, and there is no line of sight to see much of any contours or landmarks, I'd say a compass is very useful.
And for supported arm call for fire a compass is a very easy thing to use to get a a bearing to adjust off of

I'm a fan of the GPS, but I was well-trained in the use of the map and compass; some good ways to train people to work with a map is to give them a bearing and a one-grid square map of the destination. We did this at night in France; reading the map (the destination-only grid square) and everybody's SA IOT find the TGT become extremely important.

During jungle warfare trg, we were sent out with no map, but a set of bearings, distances and destination landmarks for the route. Pacing rapidly becomes your best friend...

Modern GPSs are much more effective in complex terrain. I use the Garmin Oregon, and I rarely have reception problems with it.
 
Oldgateboatdriver said:
Simple truth is never trust a single source for any information needed to carry out a task.

And that, gentlemen, is the best line of this entire topic.

What's that old quote about guns, comms, flashlights and riflemen....? Oh yeah:

"2 is 1. 1 might as well be none."

 
The quote "2 is 1 and 1 is none" is I believe better attributed to one of the awesome instructors in GI Jane.
 
If that's where you think the quote originated from, I'll let you run with that thought.
 
Rider Pride said:
If that's where you think the quote originated from, I'll let you run with that thought.

Not originated, just made popular.
 
While I gave thick brush or jungle as an example of complex terrain, i of course didn't mean those are the only types of conditions that can attenuate the signal.
The point I'm getting at is, as good as GPS is, and I agree it is an incredibly useful instrument, users need to understand its limitations

The GPS can be tracking only 3 satellites, and while this will give a very useful approximate fixation, this might continue for some time until it picks up a fourth satelite. During that time there can be some drift. Should the GPS be coupled to navigation system, and if the user had entered a location into the nav aid earlier that was not that accurate, then it is possible the nav aid will try to incorporate that difference from where it thought it was to what the user put in, exacerbating the situation.

Since GPS relies on its latitude for its direction, having a grid that is somewhat skewed can degrade any bearings displayed, though for most navigation purposes its not that noticeable.

But these things combined (bad fix and orientation) can become very noticeable if for example lasing a tgt using a system that relies on inertial/GPS navigation (and why devices like PSS SOF can help resolve them)

Another reason I believe map and compass training is vital, is from a human factors point of view. The DAGR currently in use, when used alone,  has the draw back of displaying primarily just a location, altitude, and direction/heading, whereas most civilian applications use a more effective rolling map type of display to convey surrounding information. I think for that reason alone, sound knowledge on how to use a map helps a great deal in maintaining situational awareness.
 
i have a few things to say about GPS, speaking as a DAGR (new army GPS we got a few years ago)

IT DOES NOT REPLACE PROPER NAVIGATIONAL TRAINING

That being said, GPS is a wonderful tool as long as it works.  There are a few things someone does need to worry or watch.  Do they know how to operate the GPS properly? If not they should not play around with it too much.  Are you in a situation where spoofing could apply?  If so i would not use it, just so people know spoofing is when someone is messing with your GPS signal, it will say your somewhere but in reality your somewhere else.  This apparently happened to the Israelis when they went into Lebanon in 2006.  Did not end well for the Israelis.

As well i hope people in the field are seriously not totally relying on GPS as there are times when its accuracy is less than ideal (ive seen the old PLGR with a 150km variance, I was not impressed)
 
KellGunner said:
i have a few things to say about GPS, speaking as a DAGR (new army GPS we got a few years ago)

IT DOES NOT REPLACE PROPER NAVIGATIONAL TRAINING

That being said, GPS is a wonderful tool as long as it works.  There are a few things someone does need to worry or watch.  Do they know how to operate the GPS properly? If not they should not play around with it too much.  Are you in a situation where spoofing could apply?  If so i would not use it, just so people know spoofing is when someone is messing with your GPS signal, it will say your somewhere but in reality your somewhere else.  This apparently happened to the Israelis when they went into Lebanon in 2006.  Did not end well for the Israelis.

As well i hope people in the field are seriously not totally relying on GPS as there are times when its accuracy is less than ideal (ive seen the old PLGR with a 150km variance, I was not impressed)

Pretty sure you've just reiterated what has been said in the last three pages.

Milnet.ca Staff
 
May 13, 2016

Kitchener woman follows car's GPS directions into Lake Huron, swims to shore
http://www.680news.com/2016/05/13/kitchener-woman-follows-cars-gps-directions-lake-huron-swims-shore/
Police say following the instructions from a GPS on a foggy night left an Ontario woman taking an unplanned swim in Lake Huron.
 
During my Co-op with the Pan Am / Parapan Am games, I would have been lost without GPS.
I bought a new smart phone, ensured it had a high data plan and current updates.

I had no problems where I was going. Some places were off road, but attention to detail solved
those challenges.
 
Just bought the Garmin U2Nav. Useless. The streets have no names and I still haven't found what I am looking for.
 
NavyPhoenix said:
Just bought the Garmin U2Nav. Useless. The streets have no names and I still haven't found what I am looking for.

Maybe you're not at the right elevation?

:rofl:
 
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