GPS units can be mis-read...

[Gbro]

Here is an interesting story of a hunter that claimed his GPS unit sent him in the wrong direction.
This story is remarkable in many ways!

http://pressherald.mainetoday.com/story.php?id=153359&ac=PHnws

Wright had walked for miles, following a Global Positioning System unit that he says sent him in the wrong direction.

I am posting this for the express point that GPS units can make matters worse either by miss reading or other factors.

 

[TINCUP AL]

You bet they can. I had the same thing happen to me. Luckily, I followed my instinct ( I should have had a regular compass with me ) and I made my way back to camp. Had I relied on the GPS, I would have gone in the wrong direction.

 

[ilbob]

I am betting operator error. The same thing can happen with a map and compass.

 

[teeroux]

That would suck if he would have been billed for a search when he found his own way out.:barf:

 

[Gbro]

This could be used as a reminder to all of us that we need to get our GPS Units out and brush up on its operation. I know for one that I count on my GPS much more than I probably should.

An interesting related story that I was told by a Captain of the neighboring County S/R team,
"The lost hunter had been told by other members that everyone should get a GPS, as they would be hunting a new area that fall. Well he was fortunate that he had cell phone service and was able to call for help. The S/R team had to coach him into how to even power up his unit so they could get him to read out the position!"
Now I know there must not be that many that are that unfamiliar, But that is a starting point for blissful ignorance!

 

[Gbro]

Tincup posted,

You bet they can. I had the same thing happen to me. Luckily, I followed my instinct ( I should have had a regular compass with me ) and I made my way back to camp. Had I relied on the GPS, I would have gone in the wrong direction.

I also had a related experience years back with an old Garmin 45,
I had marked the boat landing and planned to fish well after dark. I was in a hurry and didn't name it, I let the unit number it. (I had over 100 waypoints in the unit and when i put in waypoint 68 and hit the goto it created waypoint 68. The correct waypoint number was 068, as I found out a week later while figuring out where I went wrong), I did a go to to find the landing and in doing that I actually made up another waypoint. From there everything became confusing, added to that the frustration of being wrong without acknowledging the fact to myself! It took a couple of hours to locate the landing as this was a big lake and the 1st time I had fished it after dark. Then add to that the loks the wife kept giving me. She wasn't impressed with my GPS I do believe she asked again about how much I payed for that thing.

 

[grymster2007]

It's easy for us to claim operator error, but we were not in his shoes. Maybe the unit did fail somehow.

Can't see it happening to me though!

 

[hogdogs]

Being totally familiar with your unit is priority #1 when using a GPS or any device.
But a few tips that will help you a ton are time proven by my use of them.
1.Never do a cold start and mark anything. Cold start is after the unit has traveled a great distance from where it was turned off. Turn it on let it fire up and walk around with it running for a bit of time then shut off the unit and re-start it. This insures your unit "knows" where it is at.

2.Look at your satellite screen and see how many sats. you are getting and are they over head or horizon oriented.
Horizon oriented sats. give much less accuracy than overhead sats. And remember you need a minimum of 3 but 5-7 with 3 overhead is premium.

3.When you mark a spot verify you know that it is properly entered and accurately represented as for it's location in regard to your location.

4.When tracking to a marked location make sure your unit is getting full signal so it knows your present location accurately.

5.Make sure others in your party are quite comfortable with your GPS... Jist in case you are unable to operate it.

I hope these help and if I think of others I will post them up.
Brent

 

[ZeSpectre]

Another well known phenomena regarding GPSR units is "Multi-Path Error" also known as "signal bounce".

I lived in one area where they finally put a sign up alerting folks to the fact that you could get a fine GPS signal in the "gap" in the mountains, but due to the geology and topography the signals would "bounce" around (reflected back and forth by the rock walls) and your GPSR would start acting like it was in the Bermuda Triangle (spinning 'round and 'round or giving contradictory location information every few feet).

Newer unit designs compensate for this effect a lot, but are not perfect and when they do screw up I swear they do it even worse than the old units because they try to "hide" that they are confused.

 

[Gbro]

Brent,
Your point seems to be in conflict with the DOP definition in the link Zspectre provided in his post.

2.Look at your satellite screen and see how many sats. you are getting and are they over head or horizon oriented.
Horizon oriented sats. give much less accuracy than overhead sats. And remember you need a minimum of 3 but 5-7 with 3 overhead is premium.

Then again your point seems like it could be verified in the "Atmospheric Conditions" Definition from the same link.
What I did get out of that link is errors do happen, but those for the most part result in football fields size errors.

I did have a 300 mile mistake on my old 45XL years ago. I caught it and recognized the magnitude of the error and marked it before my unit reset itself and stared a search the sky function. When i e-mailed Garmin they were puzzled and stated that the military didn't give them any warning about adjustments or testing the civilian signal. Had I not been watching it happen I wouldn't have had time to mark the location that came up on my unit.
I also had my old unit loose everything while duck hunting on a very large lake. All the markers(buoys) were pulled for freeze up but I had them all in my unit.
I had to send it back in and it was replaced for $68.00. small price compared to the $350.00 or so I paid for it.
I also lost all data with that old unit when the buttons were pressed in the right way in my pack. They (Garmin) confirmed this when I contacted them.
This is done on the old ones by holding down one button like page(might be wrong on this, but one button would clear all waypoints and another button would clear all data like satellites and everything) and holding it while powering it up.
The new units do not have those old reboot feature, Thankfully.

 

[hogdogs]

The older units had inherent flaws. I had a GPS II or III plus that was one of the first 12 channel models. But it was pre WAAS technology which helped alot. The very newest models are far removed from the older ones... I have spent a few years without a unit and am itching to get another hand held.
Brent

 

[kraigwy]

GPS's are great tools, but like anything else, garbage in, garbage out.

One thing everyone needs to know about GPS, always write don't critical info when you mark a waypoint. You never can know when your battery will fail, or you loose satalites.

This happened me twice the last time I was elk hunting. I lost all data, BUT, I keep a pincel and paper in the GPS case and write down the Lon & Lat. of all critical waypoints.

Also I never do any land crusing without a map and compass in addition to my GPS.

They are great tools, but you need to learn how to use the puppy. Another thing I like better then a map/compass or GPS is a good horse. Let them have their head and they will take you back to camp SAFELY

 

[phil mcwilliam]

I was out hunting deer in the mountains 4 years ago with my friend. I have owned & depended on various GPS units for the last 15 years. In the steep valley we were hunting in I decided to cross the snow fed river as I had been following fresh stag tracks that had also crossed the river at this shallow but fast flowing section. I made it across the river ,but one step had put me in a hole that submerged me up to my waist . As we were hunting in the afternoon ,there was a time limit on the hunt in this remote Alpine region where temperatures would drop below freezing at night. I'd hunted my side of the steep valley & was heading back to the truck trying to find a better spot to cross back over this river. Once I eventually crossed back over the river I checked my GPS.The GPS unit was indicating that I should walk in a direction that I knew could not be correct because of the flow of the river.I realise rivers meandor so then got out my map & compass to double check the GPS.I then decided to walk in the direction I thought the truck was parked ,checking the GPS regularly.Both the back-track function & the waypoint function was indicating that I was walking in the wrong direction. As it was getting dark & I was wet & not looking forward to spending a cold night in the bush, I radioed my mate, which by this time was in the truck. I explained the situation & asked him to sound the horn of the truck. I heard nothing, but I still considered I was only a couple of miles away at most- but this can still be a considerable distance in the steep mountains, especially if your GPS unit is sending you in the wrong direction.My mate told me to follow my GPS. As light was fading fast I radioed my mate to fire 2 shots , I then fired 2 shots in return, & in checking compasses my "gut" instinct was confirmed- the GPS unit was wrong. Maybe it was the dunking in water-as the GPS was in my pack that got wet, or maybe it was the steep valley walls that gave the wrong signal, but there was nothing my GPS unit identified as to not having a secure fix. I have since replaced this unit, & have to admit it was probably around 3 years old when this occured. My experience with GPS units is to replace every 3 years anyway because of technology advances.

 

[Gbro]

Phil,
The 1st thing that comes to mind when reading your story and the one I posted of the Main Hunter. Is, could this be the result of "map Orientation" North Up" (being a default) then there is "Track Up" and "Course UP".
Just a thought.
I don't recall a "course up on my old unit, but enjoy this feature on my Garmin 76S.
I came across a young lady while Grouse hunting a week ago and she had an E-tracs with her. She had it turned on but that was a much as she knew about it(her husband wanted her to have it along). It was plotting a bread crumb trail. but was zoomed out so far it was unreadable. I didn't even attempt to re-zoom it as These new units are so different in operation. My recommendation is.
If you are not thoroughly familiar with the unit by all means carry the book in your pack! I do for my radio's, as I don't use them enough to remember how to activate the weather band feature, Until I start to read it and it comes back quickly.

 

[lt dan]

when i was in the army, the rule was always to use a gps alongside a map and compass. i have seen many gps related confusion, when we did some troubleshooting we always found pilot error. that is not to say a gps cant be wrong, so i still recommend a compass and map and most of all: common sence