GPS units are notoriously inaccurate out here in the puckerbrush of Wyoming, not unusual at all for tourists, etc, to get totally lost trying to use them, once a year or so someone tries to follow one in the dead of winter only to wind up stuck in a snowdrift way out in the boonies and freezing to death. Below is a typical account from today's blotter:

"Monday morning around 10:30 a.m. a subject from New York was traveling on Sand Draw Road. The subject was reportedly utilizing a navigation device that told him to turn off of the State Highway and onto a two track dirt road off of Beaver Rim in order to reach Riverton. After several miles he became lost and disoriented. He was located and followed a Deputy back out to the highway and into town."

We shot an elk 600 yards down a 35 degree slope at dark. Used the "project waypoint" feature where you lock in the azimuth visually and enter the estimated distance. We has a laser so it was a wee bit better than an estimate. Went to camp, ate dinner and packed up. After a nerve racking slide down a boulder and scree field in the dark went right into the dark timber and found the beast lickity split. GPS works.

mapquest has sent me on some wild goose chases. have had good luck with good gps's.
downed a Elk one year and had a buddy with a helo that said to call if i did. took a waypoint, texted him the CO's and he flew straight to us. only way to pack elk!

The problem is rarely the device (whether GPS, compass.... or even a gun). Operator error is the reason, and the only reason, that GPS doesn't work 99 point-a-high-something percent of the time. (And failing to know that your unit is not communicating properly is part of the operator's responsibility. Various software add-ons might be a separate issue; can't say from experience.)

Mine has worked within sight of the truck when I used it.
I've trusted a compass a few times and came out right at the boat or truck.

I have one, but don't use it much. If I am going offshore fishing, I'll take it.
In the woods I hunt, don't really need a GPS. I have maps, and know the land pretty good.

Big diff between a true GPS setup and something like Map Quest. Almost all GPS foul-us are the operator.

In unfamiliar country I usually mark a point at the truck with my old Garmin then turn it off and use compass or dead reckoning to hike. Have found myself not quite sure of the trucks whereabouts a couple times but when turning the GPS back on found it was just over the next hill. Oops. Don't like to depend on them but they sure are nice.

I have three GPS units and a stand-alone topo mapset/gps ap in my phone. have never been lost with one of the four.

I like my map/compass, but gps is usually the best tool for the job when traveling.

Map quest sucks! Had an job interview at a hospital about 30 miles from my home. Got directions off of map quest and did a trial run the day before the meeting. Followed the instructions almost to the end and then it tells me to go straight at a 4 way intersection and the destination was 1/2 a mile ahead. Only problem was that the intersection was only a 3 way and straight would have put me into Long Island Sound! They were right tho, I could see the hospital across the harbor! Have never used it again!

My hand held GPS has never failed me, however, my car GPS has many times placed me in a spot that I did not want to be. One time it got me to around two hundred yards of where I wanted to go...but there was a stream between me and there and no road. Had to back track and use the maps to get there. Have started using the I-phone GPS when in the car rather than Garmin.

I drive 150,000 miles a year in the big rig. I live and breathe by my GPS. I have a $400 Rand McNalley.
Great device, on a 1,200 mile run it will bring me to the gate within one foot. Can't live without it.

funny thing about navigation GPS units, they all put folks about a mile from my house. In a field

I wouldn't say "most" error is user error.

My experience with error is mostly associated with multipath errors, ephemeris errors and poor PDOP/ actual physical obstructions. Mountains or tall buildings block the individual birds, especially the low horizon birds.


But I'm wasting my breath with the FKIAs.

Major errors occur when a driver turns off a set route for some reason and the GPS tries to navigate from the new location. It will pick an entirely new route, often where you really don't want to go. My Garmin will try a few times to return me to the original route and when I don't follow it, it can come up with some pretty wild alternatives. Its just a brainless computer and when it thinks I don't want to take its advise it'll keep trying.
Common sense comes in handy sometimes. It also helps to look at a paper map on occasion so you know generally where you want to go. If the map says you want to be on Hwy 30 and after a few detours the GPS has you on Podunk Road, that common sense should tell you that you have a problem so STOP.

GPS is awesome. I trust mine, but that doesn't mean I don't carry a map and compass and know ways to find coordinates in the area's I hunt. My GPS has never let me down and I seriously doubt it ever will. I also believe the OP is talking about car GPS systems. I remember one winter driving up to my shooting pit and coming up on a semi stuck in the snow. He said he was following the GPS directions and it led him to this road which was a non maintained road that is eventually closed to vehicles over 48" wide in the winter. The biotch of using a car GPS is it looks for the shortest route and sometimes that shortest route is not possible....

It seems to me, after a few years and several different GPS units, that it isn't the GPS system, but one or more of:

The mapping
The settings
The operator

Mapping can be inaccurate, and of course can also be out of date. One route I follow for example, was only opened a couple of years ago, as a freeway bypassing a number of towns. It confuses the hell out of the GPS built into one car, because that GPS mapping dates from 2011, and hasn't been updated since.

The settings seems to be the next one. You can set your typical in-car unit to avoid minor roads, for example, or avoid toll roads or U-turns. I've learned this after a couple of times using GPS in rentals, and discovering that the GPS is set to avoid toll roads and so it sends me through the suburbs.

Finally there's operator error - the obvious issue when people do silly stuff like heading off into the scrub just because "the GPS told me".

I am a fan of GPS, and use it both in-car and in the bush. I find it a really helpful technology - I wouldn't want to go back to the days of pulling over to check the street directory, and I find it great in the bush for marking downed game, marking the position of camp etc. However I don't give myself over to it completely and always have a back-up (map and compass). Only an idiot would give over all the decision making to a device.

On thing I find especially useful in strange cities is the split window with an enlargement of the upcoming interchange and showing me which lane I need to be in. I haven't been steered wrong yet.

There are three system components to GPS: the system, the receiver and the maps. The system (satellites and timing) are VERY accurate; the receivers vary in how they process the data (generally, the more expensive receivers are very accurate and process data quickly), and; the maps (supplied by commercial vendors whose accuracy varies all over the map!).

I was involved in developing (30 years ago) and commercializing (25 years ago) GPS and the first receiver I bought (on the Government dime) cost $250,000+ dollars (1992 dollars). Today, you can get similar performance for $8,000-$10,000. Basically, you are paying for quick signal acquisition and processing time.

Not at all. Ever.

I seldom use a GPS unit. Most often in large cities I'm not familiar with like Denver or Seattle.

Last used it last weekend when we went for an overnight camp trip. Weather was due to turn so I way-pointed when I was off Lockhart point, then again 6 miles away once inside the mouth of the Noatak, across Kotzebue Sound. Sure enough next morning was fog/mist/rain with visibility up to a mile at times. Got to waypoint 2 vicinity (judging by sandbars on either side) and could just make out the point across the Sound. . Way I like it! It's a straight n/s shot by compass. Allow for 16 degrees declination.

Since I have twice had a GPS unit fail when I wanted it, I always carry a compass and when called for, a map. Neither will have an antennae go south, or the satellite "roll over" in the middle of the day after the unit tested functional that morning. A compass let me sleep at home in a comfortable bed both times, rather than at my camp. (Damned thing is always wandering off!). Not to me toon batteries having the potential of going flat at the most I opportune time. Never happened to me, but I carry spares anyway.

My cousin, a fanatic for the latest and greatest things, like them little phones they slide their greasy fingers all over to flip through pages and stuff, always mentions his GPS. Interesting thing about GPS is he has never found the shortest route to my house from Oregon, and it's all freeway. So I break out the AAA map and show him how to cut 40 miles and a lot of traffic off the route. That didn't help, next time he calls from Antioch, California asking how to find his way. Said he must have made a wrong turn. I told him it couldn't be done, he'd have to go back to Oregon and start over. Good thing he had his daughter and wife with him, or he'd have never stopped for directions.

Next time, I had written down the route. He calls and says it seems to be working. I ask where he is, he says he just went through the big tunnel. What tunnel? I ask. There isn't any tunnel on the route. Turns out he didn't believe me and followed his GPS, it was the Caldecott Tunnel. He was driving miles out of his way toward Oakland, after exiting I-680 South. He finally arrived about two hours late and frazzled.

Last time he visited, he was going to see his father in Exeter, California after stopping at San Simeon. later I found out that after leaving San Simeon, they had driven two hours the wrong way on Hwy 101 before catching on and turning around. He finally found Hwy 198 and on to Visalia and Exeter. Sort of roundabout but he made it. I told him the best thing he could do with that GPS thing was toss it out the window and clean the suction cup rings off the windshield.

Back in the day, when I worked at a huge show horse farm, I'd ride Rosy down to the store and post office, and never once got lost because Rosy knew she'd get an apple or a Hostess Apple Pie for a treat, and she always knew the way home for dinner. Yep, a living GPS. Ah, those were the days.

Well, if u ain't smarter than a GPS........ It aint going to turn out well. .

Goes for horses too. In that case the rider has to be smart enough to let the horse do the thinking in fog or dark. BTDT. They always know where the goodies are.

The GPS system itself, satellites and receiver, is incredibly accurate. The map databases are what's usually screwed up especially in rural areas. When you've got a county road that's 20 miles long and you enter in 10174 CR 5184 you might get sent to one end of the road instead of the other. The GPS still knows exactly where it's at in Lat/Long's, but the map is screwed up so it can't translate the lat/long to the address.

I fly for an airline and our aircraft use inertial reference units constantly updated by GPS to navigate. They're incredibly accurate, so accurate that you'll be halfway across the north atlantic on a route with another aircraft coming the opposite direction on the same route 1000' above or below you & your fuselage will align with theirs when you pass, every time. If we were co-altitude then we'd hit. They now have us doing an offset maneuver designed to prevent that in case the altitude split gets messed up.

Yes. I absolutely trust my GPS units. Those that might furnish the underlying data, not so much. Much of that has been traced from out of date maps depicting long abandoned or inadvisable ways.

One must have at least half a brain if he's trusting roadway navigation data.

Was looking for an address in Central Oregon one time. It told me to turn left but when I looked there was a sign on the fence post saying this was not the road to *** St. We turned around and the gps kept telling us to turn where there was no road but just a culvert. Years ago the land had been laid out and subdivided but nevr been developed. The gps map was telling us to take those roads.

Garmin recently did a highway map update. They moved our house and several of the neighbors 3 miles to a different highway. I reported it to them and the correction is supposed to be on the next update. We'll see.

GPS is great at knowing where you are, and knowing the point you are navigating to.

The problems start when they calculate the route between the two places.

My Garmin will calculate the route using mostly the main routes, often not the shortest one. Its after you leave the route and it has to recalculate that the problems start.

Have seen the GPS get travelers in trouble more than once

in our local area....unmaintained winter Forest roads

It's not the GPS that's inaccurate, it's the mapping software. I'm using a GPS system right now that's showing my accuracy at .027m X and .026m Y with a .032m Z value. Would be more accurate but we're running 26 knots.