Accuracy test of the GPS Features on the CTX 3030.

[Doctorcoinz]

Well just for fun I thought I would test just how accurate the GPS features are on my CTX 3030. The best way to do this is to hunt a marked field , this old football pitch served the purpose well. The black hole with the arrow pointing to it is where I started to hunt. I worked my way all round the perimeter and had the geohunt set to record the hunt. The accuracy is not as good as I expected , when you look at the geotrail that I recorded you can see just how skewed the whole gps recording is. The accuracy is supposed to be within about 1 metre or so from what I read but as you can see we are looking at an "accuracy" no where near a metre , infact the accuracy is actually 7 metres or so . I had gps set to enhanced , what do you think? This is not accurate at all , no way can find points be recorded to within a metre of accuracy. Like I say it seems it is not all that accurate or precise at all but just a rough approximation.

 

[foreign object]

Yea there are more expensive gps units on the market that will have a hard time getting you within a meter of a target. I have not even tried using mine. I turned it on and let it locate me but saw real fast the resolution is not there for any kind of real accuracy.
Was a waste of minelabs time and my money. The Gps on the CTX had nothing at all to do with my decision to buy but as with all things either build it right or don't build it.Most folks wont know it's not worth a hoot as most don't know enough about gps to compare.

 

[Doctorcoinz]

I agree totally, the gps features are not as accurate as some claim . , I am not saying the gps features are useless, the gps feature is a rough guide only. .Maybe my hopes were too high. On massive fields I suppose if all the find points are recorded then it could show general patterns or hot spots so it is not a completely useless feature.

 

[GKMan]

Maybe my hopes were too high. On massive fields I suppose if all the find points are recorded then it could show general patterns or hot spots so it is not a completely useless feature.

Your hopes are way too high...Just because you have it set to enhanced (WAAS) doesn't mean you are getting that level of accuracy if the signal strength isn't strong enough. Most GPS sites appear to be saying that you can expect a three meter accuracy with WAAS in optimal conditions, some say five meters..

I consider the GPS to be a frill that is nice to have but for where I detect with numerous landmarks to tell me where I am it isn't required.... Now, years down the road when I try to think back "Did I already detect this part of the field?" I may be kicking myself in the behind thinking that I could have quite easily been capturing this data since 2012.

 

[AngelicStorm]

Did you know that in Xchange2 you can move findpoints? I sure do it. I consider the Enhanced GPS accurate enough to come within reasonable distance of the point of interests. If you did not know, the U.S. Government moderates GPS tracking for safety and privacy reasons. Here is an article on GPS accuracy I think may interests people..... http://www.gps.gov/systems/gps/performance/accuracy/

 

[DaveMcC]

I kind of agree with GKMan about using available landmarks. I don't have a lot of wide open fields with minimal landmarks where it might be useful but I did give it a spin at the beach a few weeks ago for more or less the first time. I gotta say I was pretty happy with its accuracy for my hunt. It also calculated how many yards I walked which I calculated to just under two miles.

 

[Yeasty]

I don't use Xchange2 for GPS tracks, Waypoints or Findpoints. I've figured out how to extract the data directly into my computer, format it, then convert it to .kmz files for Google Earth. Using GE is much more versatile than Google Maps. You can store and view many tracks at a time. Same for Waypoints or Findpoints.

 

[AngelicStorm]

I don't use Xchange2 for GPS tracks, Waypoints or Findpoints. I've figured out how to extract the data directly into my computer, format it, then convert it to .kmz files for Google Earth. Using GE is much more versatile than Google Maps. You can store and view many tracks at a time. Same for Waypoints or Findpoints.

There are risks in doing it the way you are talking about from what I understand which means people have to be careful trying that method. Here is the thread you created on what you mention.... http://www.findmall.com/read.php?86,2036835,2036842#msg-2036842 . You created it about a month ago and I read it back then.

I have not tried it.....

 

[Overvoltage]

Doctorcoinz..I have had accuracy problems with the GPS from day one. Here is the thread. http://www.findmall.com/read.php?87,2021066,2021066#msg-2021066
I love using the GPS. I record every hunt and analyze where I have hunted using find points. I have just come to accept that the GPS is off by at least 10-15 feet.

 

[Digger]

The accuracy of the GPS features on the CTX3030 is dependent on GPS satellite information and WAAS, which is a satellite-based augmentation system operated by the Federal Aviation Administration. http://www.gps.gov/systems/augmentations/

As GKMan suggested, accuracy of the GPS on your CTX3030 will depend on where you are located, as well as several other factors.

Here is a current map of WAAS....

[attachment 288813 WaaspicSmall.jpg]

 

[CTX3030]

I have used the GPS feature on the CTX to return within 3 feet of a Find Point or Waypoint. Not on one occasion but on many. I am in the process of hunting a 40 acre field and use Geohunts to track where I have been. At the end of the hunt I create a waypoint as the start point for my next hunt.
I return to this start waypoint on my next hunt. I use fiberglass driveway markers (the stick type with no reflector top) to grid the area I am hunting. I create a find point for every worthy find. I find the information invaluable. Areas of this field have been filled and I can tell which areas are original and what has been filled by age of my finds. GPS accuracy may be much better in my area, but I have never had a problem with using it and find it is a great tool.

 

[GKMan]

Curious if you are you located near one of the WAAS stations?

 

[Doctorcoinz]

There was high tension power lines on the field , I am thinking maybe these could affect the accuracy.

 

[foreign object]

If not mistaken the W.A.A.S is only avaliable along the coast line. Been a long time since i kept up with such things.

Accuracy will not only depend on the location of satellites but how many your machine can/will pick up. Not sure how many the CTX can pick up at once but the more the better.

At some time after 2000 the government turned of Select Availablity ,think that is what its called,which added to accuracy and i assume it is still off.

 

[CTX3030]

Curious if you are you located near one of the WAAS stations?

The closest land based WAAS Station is 200 miles away but WAAS corrections are provided by Satellite. Here is an explanation of WAAS I found

"WAAS uses a network of ground-based reference stations, in North America and Hawaii, to measure small variations in the GPS satellites' signals in the western hemisphere. Measurements from the reference stations are routed to master stations, which queue the received Deviation Correction (DC) and send the correction messages to geostationary WAAS satellites in a timely manner (every 5 seconds or better). Those satellites broadcast the correction messages back to Earth, where WAAS-enabled GPS receivers use the corrections while computing their positions to improve accuracy."

I believe there is a WAAS satellite parked almost over my state of Maine and I am about 40 miles from the coast.

 

[goodmore]

I have only used it a few times but my recorded hunts were more accurate than that. I could see where I circled trees. I could see where I turned in circles on a target. I could see where I went up the side of a church that is on the grounds. I don't know all the tech stuff about GPS and government standards, but I'm here in southern PA and it sure looks like the results vary.

 

[GKMan]

there may be an assumption that the GPS on the CTX is the problem, but what if it is really the maps we are looking at?

it would be interesting to see what would happen if you put your Garmin or smartphone GPS alongside the CTX and see what the different readings are actually.it would also help to have a benchmarkor some other latitude and longitude that you know to be accurate

 

[Digger]

You are mistaken. That is why I inserted a WAAS map in my earlier post. http://www.findmall.com/read.php?86,2049831,2050124#msg-2050124

 

[foreign object]

I see your map but like i said i had been away from the GPS type stuff for a while. When they first started using WAAS it was limited to the coast areas and as your map shows the majority of the coverage is still along the coast lines in the lower 48. Dont see much coverage in the central usa and im sure you can correct me but at one time the coveragewas limited to somthing less than 200 miles which may explain why the east coast is covered so heavily. WAAS was mostly designed for marine navigation hense the heavy east coast coverage.

Spending a lot of time fishing offshore installation of WAAS and the gov. shutting down Select Availabilty was a big help.

 

[Doctorcoinz]

I think after reading all the posts about this test maybe some one else would like to scan a football field and post the results - I think the tests of accuracy will be about the same as my test. I may be wrong...