Calibration of GPSMap 60CSx?

[+Fogtripper]

Today I am getting a +/- of about 20' on my location. Yesterday the best I could get was 15'.

 

I am picking up plenty of satilites and a clear view of the sky. Also, my Topo 2008 shows my street, but shows me on the wrong side of it. Probably a good 25-30 yards off.

 

Is it the map being off in relation to my location, the map correct but the unit showing the wrong location? Is there a way to calibrate everything to a known location? Should I be getting better than +/- 16' to 20' on my loacation?

 

Not a lot to be found on a web search (even when you jump over the bazillion advertisement links for the sale of the unit)

[Motorcycle_Mama]

+/- 20 feet is about what you would expect to get with all recreational GPS receivers.

 

25 - 30 yards is probably a little too far off, though.

[eaparks]

On my 60CSx I usually see 15' - 25' as the accuracy. The accuracy displayed on your GPSr is only an estimate and is not intended to be telling you "exactly" what your error of accuracy actually is (just a rough approximation). Just because you and a freind may be standing side by side, each with your own GPSr and yours shows an accuracy of 22' and your friends shows an accuracy of 9' doesn't really have any significant meaning concerning how accurate the GPSr really is. To get a true test of the accuracy of a GPSr you need to go to a benchmark that has been adjusted (not calibrated) and then compare your coordinates with the benchmark's coordinates and see how far you are off, you may be surprised to see that you are only a few feet off.

 

As far as Topo 2008 being off, I see the same thing with the U.S. Topo ver. prior to 2008. Some of the time where the GPSr says I am as compared to the topo streets will vary as much as 80', but with CN NT v8 I am usaully right on.

[+Prime Suspect]

Today I am getting a +/- of about 20' on my location. Yesterday the best I could get was 15'.

 

I am picking up plenty of satilites and a clear view of the sky. Also, my Topo 2008 shows my street, but shows me on the wrong side of it. Probably a good 25-30 yards off.

 

Is it the map being off in relation to my location, the map correct but the unit showing the wrong location? Is there a way to calibrate everything to a known location? Should I be getting better than +/- 16' to 20' on my loacation?

 

Not a lot to be found on a web search (even when you jump over the bazillion advertisement links for the sale of the unit)

Topo streets are notoriously bad. Not surprising, since they haven't been updated in decades.

[+will2trade]

Topo 08 shows my home 900' away from where is really is , I returned it and went back to the older version. Garmin tech support said they are having alot of inaccuracies showing up.

[+Sputnik 57]

Is there a way to calibrate everything to a known location? Should I be getting better than +/- 16' to 20' on my loacation?

Go to the GC.com website and click on Benchmarks. Find a benchmark near you and compare your coordinates. Make sure that you use a benchmark labeled as "adjusted" and not "scaled." Adjusted benchmarks are accurate to within centameters.

[+Cacheoholic]

I placed a Geocache about 20’ from an adjusted benchmark and used the benchmark coords so people could see how accurate their GPS is. My 60CSx was reporting 15’ accuracy but was actually only 6’ off. The 60CSx seems to report a very conservative accuracy reading.

[Glenn W]

My experience is that the accuracy of the Topo 2008 streets is dismal. Streets in my community (developed in the 1940s) are shown off by about 200 feet. I like that they added street names and terrain shading to Topo 2008, but it seems accuracy was low on Garmin's priority list. By comparison, the CityNav, Metroguide, and even the older Topo street maps for my area are very accurate. I suspect Garmin bought cheaper street cartography for Topo 2008 to keep the costs down. I hope they didn't deliberately degrade the accuracy of Topo 2008 streets simply to maintain sales of their street software. Oh no; I smell a conspiracy theory.

Edited October 15, 2007 by Glenn W

[+JSWilson64]

Along with the other good replies above, remember there are various atmospheric error sources in the GPS signal that can vary from time to time, even with clear blue sky every day and the same satellites overhead. I think it's a pretty common misconception about the accuracy of the whole System - anything less than 10 meters is gravy, IMO. Unless you're calling in an airstrike or artillery, 15' is a pretty good fix on your position for a consumer-grade GPS, even a 60CSx.