Accuracy Of Unit ? Legend

[+troylball]

Hi all

 

Santa sent me a Garmon Legend for Christmas and I found my fist cache today, Hurray !!!

 

I have a couple of questions about accuracy of the unit. When I first turned it on it said the accuracy was 35 ft and as I walked around it fluctuated between 20 and 35 ft?

Q1. Is this normal? I thought that GPSs were supposed to be accurate to within 5 ft?

Q2. Are all units the same? i.e. do higher end units have better accuracy?

Q3. If you read this topic could you respond with your GPS make/Model and typical accuracy you receive

 

Your help is appreciated,

tball

[+Team Og Rof A Klaw]

(Q1) Yup, it's normal. I've never had 5 foot accuracy. (It's possible on the fancy military units, but not on commercial grade stuff.)

 

Q2) See (Q1). Enabling WAAS might help if you're in an area that it covers.

 

(Q3) Garmin GPSMAP 76S. Seldom gets better than 20 feet. 30 feet is typical.

 

HTH,

- Team Og.

Edited December 26, 2003 by Team Og Rof A Klaw

[+Sparky-Watts]

I've got the Legend, also, and I typically get 13 to 18 feet accuracy, a bit worse on cloudy days. Money won't buy you better accuracy, just more features to use the accuracy that you have!

 

EDIT: best accuracy I ever had was 7 feet, but that was only twice!

Edited December 26, 2003 by Sparky-Watts

[+Brian - Team A.I.]

GPS units are accurate to ~3m >95% of the time, which equates to approx. 9', but you typically see ~16' of accuracy in most situations. Depending on the day, I find myself with anywhere from 8' to 16' accuracy while driving, more often than not it's sub-10' accuracy tho. Factors affecting accuracy are things like buildings, outside EMF interference, rock faces, tree cover, etc.

 

Higher-end units DO have greater accuracy (centimeter accuracy), but you're looking at an awful lot of 0's added to the price, as they are professional surveyor grade and better.

 

My GPS unit is the eTrex Vista and I typically keep WAAS on, as it's most often found in my windshield mount running of truck power.

Edited December 26, 2003 by Brian - Team A.I.

[+Team Og Rof A Klaw]

Warning, geeky stuff:

 

BTW, the Global Positioning System works by measuring the speed-of-light delay from the GPS satellites to your GPS receiver. Much of the inaccuracy comes from ionospheric delay, which varies enough to throw a GPSr off. Commercial stuff tries to compensate by simulating the delay and subtracting the simulated number from the satellite-to-receiver delay.

 

High-end gear is able to receive another signal on a different band and get a more exact, direct delay measurement.

Edited December 26, 2003 by Team Og Rof A Klaw

[+Halden]

I have a Legend and have been using it for almost a month. I would say on average I have been getting an accuracy of 3 to 5 metres. I have been quite happy with it. If your GPS can get you to within 3 metres of something and you can't find it then blame yourself no the unit.

[+troylball]

Thanks all, for your quick responses. That’s exactly what I was looking for .

 

tball

[+Team Fegel]

I havnt been geocaching for very long, but I have been using GPS for years. Prior to Sept 2001 it was not uncommon for me to get 15 feet or less accuracy on my work's Garmin Etrex (yellow case). After sept 2001, I had never seen accuracy less then 35 feet (okay occasionally lower then 35). I just got a Garmin Legend yesterday and when I was able to get a WAAS satalite, I had 5-10 foot accuracy today. Just thought I would throw that out.

Edited December 27, 2003 by jfegel

[+the4Grays]

Hi all

 

Santa sent me a Garmon Legend for Christmas and I found my fist cache today, Hurray !!!

 

I have a couple of questions about accuracy of the unit. When I first turned it on it said the accuracy was 35 ft and as I walked around it fluctuated between 20 and 35 ft?

Q1. Is this normal? I thought that GPSs were supposed to be accurate to within 5 ft?

Q2. Are all units the same? i.e. do higher end units have better accuracy?

Q3. If you read this topic could you respond with your GPS make/Model and typical accuracy you receive

 

Your help is appreciated,

tball

I have a Garmin Etrex Vista,and Emap and the best i have gotten with either is 10 feet and that was only a couple of times,on very clear days.Even with Wass enabled Higher end models just have more extras.You will get use to the accuracy and what effects it shortly.Then have fun with it.

[+Sparky-Watts]

Besides, when you get 15 to 20 feet from a cache, it's time to stop watching the GPSr and start looking around for the cache!

[Kerry.]

.... prior to Sept 2001 it was not uncommon for me to get 15 feet or less accuracy on my work's Garmin Etrex (yellow case). After sept 2001, I had never seen accuracy less then 35 feet (okay occasionally lower then 35).

Sept 2001 has no bearing on GPS accuracy, but it appears many thought and still thing so.

 

Cheers, Kerry.

[+KiltCacher]

Just adding my two cents- I also have the Legend, and have had really good accuracy with my unit (unless there is heavy tree cover or close to buildings). Over the last three days it has been amazing though. I've been averaging 5 to 8 feet! Normal reading is about 10 to 15 feet on average. At that proximity I'm usually tripping over the cache anyway.

[+harleycache]

Hi all

 

Santa sent me a Garmon Legend for Christmas and I found my fist cache today, Hurray !!!

 

I have a couple of questions about accuracy of the unit. When I first turned it on it said the accuracy was 35 ft and as I walked around it fluctuated between 20 and 35 ft?

Q1. Is this normal? I thought that GPSs were supposed to be accurate to within 5 ft?

Q2. Are all units the same? i.e. do higher end units have better accuracy?

Q3. If you read this topic could you respond with your GPS make/Model and typical accuracy you receive

 

Your help is appreciated,

tball

I too have a Legend, and usually have accuracy to about 18 feet. Sometimes better, sometimes worse.

[cutsandbruises]

I have had my Garmin extrex Legend since September and these are my thoughts on accuracy.

• When you first turn the GPS unit on make sure you wait a few minutes for the GPS to pick up satellites..
  
• After a few minutes my accuracy is about 19 ft
  
• As I get closer to the cache I find that my accuracy is usually dead on 0-3 ft
  
• I then check the coordinates and they are usually dead on too.
  

If my GPS says I'm that close I'm usually standing still and thats when the unit starts to spin. You have to keep moving to get accurate readings.

When I'm 10 feet away i just start to look.

Once I find the cache I place my GPS right on top of it and check the coordiantes again for accuracy. I make a note if they are drastically different then the ones posted but that has never happened to me yet.

[Major Catastrophe]

I'm pretty new to GPS (Christmas) but I'll jump in here anyway. Current units are accurate within ~3 meters with WAAS info, or about 10 feet. So your unit can get you that close to the waypoint of a cache, BUT -- the person who originally hid the cache also had an accuracy of 3 meters. That means that the errors might cancel, and your GPS will put you right on top of the box, or they may add and the best you'll do is to get within 20 feet. So with everybody's ducks in rows, there is still an uncertainty of 6 meters (your error plus the hider's error.)

[DiverMan]

Just adding my two cents- I also have the Legend, and have had really good accuracy with my unit (unless there is heavy tree cover or close to buildings). Over the last three days it has been amazing though. I've been averaging 5 to 8 feet! Normal reading is about 10 to 15 feet on average. At that proximity I'm usually tripping over the cache anyway.

I also have a legend with the latest firmware upgrades. I have been getting exceptional accuracy. I have had as low as 4 feet!! On a bad day (probably because my batteries are weak) I get 20+ feet. I am very happy with my legend...

[4x4van]

One other thing to consider is that the accuracy listed on your GPS screen is that unit's estimate of it's own accuracy. That number may or may not be the "real" accuracy, since it is based not only on satelite strength/position/etc, but also the unit firmware's method of calculating it's own accuracy.

 

I use a Magellan SporTrak Pro with WAAS, and my son uses a Garmin E-Trex Yellow (no WAAS). The E-Trex typically says that it is a bit more accurate than my ST Pro (15-20ft vs 20-35ft), even though it shouldn't be, considering that I am in an area where I can receive WAAS signals (yes, I've tried turning WAAS off, and EPE gets worse). Since neither one seems to have a clear edge over the other in actually getting us to a cache, I've come to the conclusion (perhaps flawed, but...) that the Garmin's firmware is just a bit more "optimistic" than Magellan's is regarding it's own accuracy. Kinda like a Ford telling it's owner how good it is...without independent verification, can you really believe the Ford? (Please, no Ford vs Chevy debates...that was simply an example )

Edited January 20, 2004 by 4x4van

[+RIclimber]

I have a Garmin Etrex Vista. In the summer in RI I was getting 15'. Now it's around 55'. Does the cold have anything to do with that?(20-25º)

[+GeckoGeek]

I have a Garmin Etrex Vista. In the summer in RI I was getting 15'. Now it's around 55'. Does the cold have anything to do with that?(20-25º)

There are many things that can influence that. If your view of the sky is blocked in some direction, that can be a problem. What I mean that under ideal conditions, you will want a view of the sky all the way down to the horizon in all directions. Also the satellites may not be in a good alignment for you. The more sats you can pick up down low closer to the horizon, the better off you'll be.

 

It gets worse if there happens to be an obstruction right where a satellite happens to be right then.

[+1setter]

Money won't buy you better accuracy, just more features to use the accuracy that you have!

 

Money can buy you better accuracy, but we are talking thousands of money, not tens or hundreds.

[+lazylightning]

I have a compass course that I set up for my daycamp program in Jefferson City MO(compass heading & distance) and thought I'd set it up as waypoints for a gps.

 

I found this very interesting. I ran the waypoints on my Garmin Legend and at the time, I had about 15-18 foot accuracy. A couple of weeks later I got our Park Planner out with his $10,000 Tremble backpack unit. I compared 8 waypoints. On every latitude measurement, I was either right on or 1 off of his measurements (38.36.176 vs 38.36.177). On longitude, there was a little more discrepancy. I had one that was exact, 4 that were 1 off, the worst was 5 off (92.18.272 vs 92.18.267) The ones that were off the most had some tree cover to the north but were clear east & west. One set exactly matched lat & long with the Tremble.

 

I was very impressed by the performance of the Garmin after that.

[Cachengrab]

Well my Garmin RINO 120 was not hundreds or thousands more and it is so accurate. How accurate you ask? When I put in my co-ords I set the my GPSr to GPS"R" which is the Rino function for retrieve and wait while it goes to and brings back the Cache for me. I sign the log set the GPSr to GPS"RR" and then it replaces the Cache back to its original position.

[+mozartman]

just adding my experience with the legend-- about the same as Halden's. with a couple dozen finds and about 6 months use, the legend almost always gets me within 10 ft of the cache. I am only doing urban caches, though, not ones up in the mountains, and there's not a lot of tree cover or physical features that could block a signal. (Arizona)

[+harleycache]

Got a Legend, been doing gc for a couple of months now and try to find time to get a couple searches in each weekend. My Legend usually puts me within spitting distance of my finds.

[+Hiemdahl]

I have been using the trusty Legend for several years now. In fact, I prefer it to the PLGR (weight, size and most important BATTERIES!). Accuracy has never been a problem except in urban areas where there is masking and multi-path.

 

Note, sub-meter accuracy is possible with commercial units. It's a matter of sitting still long enough and averaging the results.

 

Happy Caching!

[HDLowrider]

Also just got a Legend at Christmas, I've been a good boy, Santa loves me

I'm in the UK , just to the SW of London. I have found generally the accuracy is about 16 - 21 ft . I'm well impressed . Haven't been out looking for GC's yet but intend to this weekend. WAAS isn't visible to the unit here.

Best Wishes to you all.