Oregon accuracy ?

[+Rifty]

I've just upgraded from a legend hcx to an oregon 300 (and updated the oregon to 3.20 last night).

 

After the update, I had the two side by side in the conservatory and the (trusty) legend hcx was showing an accuracy of 9ft. The oregon 300 was 40+ft ! This slowly came down to the 20-odd ft and eventually settled at 17ft after around 50 minutes (waas was active by that point - lot's of D's on the sat bars) !

 

I know it's suggested that gpsr's should have a clear view of the sky and be left for 30 minutes to re-acquire almanac data after an update. Could this be the issue ? The conservatory roof was hampering things ?

 

On the drive in to work this morning, the tracklog showed major spikes off into fields (gps was in the glove box). Again, nowhere near as accurate as my trusty legend hcx would be in the same place. Did I make a bad choice with the oregon ? Is there anything I can do to improve the accuracy ?!

 

Please help !

 

[+Native20559]

I've just upgraded from a legend hcx to an oregon 300 (and updated the oregon to 3.20 last night).

 

After the update, I had the two side by side in the conservatory and the (trusty) legend hcx was showing an accuracy of 9ft. The oregon 300 was 40+ft ! This slowly came down to the 20-odd ft and eventually settled at 17ft after around 50 minutes (waas was active by that point - lot's of D's on the sat bars) !

 

I know it's suggested that gpsr's should have a clear view of the sky and be left for 30 minutes to re-acquire almanac data after an update. Could this be the issue ? The conservatory roof was hampering things ?

 

On the drive in to work this morning, the tracklog showed major spikes off into fields (gps was in the glove box). Again, nowhere near as accurate as my trusty legend hcx would be in the same place. Did I make a bad choice with the oregon ? Is there anything I can do to improve the accuracy ?!

 

Please help !

 

 

Acquiring the Almanac on a new unit has always done good things for the accuracy of my 200 whenever I drive any significant distance (+ 100 miles) from home. Do the same thing for my 76CSX (very similar to your Legend's accuracy). I usually set ot on a table or car hood and wait 20 to30 minutes in "normal" mode (not battery saver) and that's usually all it takes.

 

Give it a try. If that doesn't improve things, try a factory reset of the unit. You have have had a bad update or something that affected the operation of the unit, hard to tell but since it's new you won't lose anything trying.

 

Good luck.

[+Tequila]

I found an underwater cache today and the Oregon was bang on. I was standing in the water and the OR said the cache was 2 meters to my left and that is exactly where it was.

 

Using 3.15 Beta

[+Searching_ut]

I wouldn't expect any of the newer units to do any better accuracy wise than your old trusty eTrex. You'll find some differences in the way they behave while moving through canyons and stuff, but they are just different methods of handling signal loss, multipath etc. Basic accuracy has pretty much remained the same. Myself, I think the H series GPS units are greatly under rated. Hiking the backcountry, you see lots of people using them. They're rugged, small and lightweight, fantastic battery life, easy to use one handed, and extremely dependable. I know if I'm headed deep into the wilderness on a hiking trip and the choice is either my PN-40 or eTrex C, the eTrex is the one that will guide me in and out.

[wahoowad]

Can some please explain "Acquiring the Almanac" to this noob?

[+Searching_ut]

Basically, piggybacked on the GPS signal is data on where the satellites will be at any given time in the future. With this data, by knowing the time, and approximate location the gps receiver knows what satellites to look for, and approximately where they should be. For the GPS receiver to obtain this information and store it for future reference takes 15 minutes or so of uninterrupted reception.

[wahoowad]

And then it remembers this info until you do something like update the software, or power it up far, far away?

[+Rifty]

To somewhat answer my own question, I find the oregon accuracy indoors less accurate than the legend hcx - mid twenty feet rather than low teens of the legend hcx (like for like test).

 

However, when tested outside (and with no waas lock), I've had accuracy of 10ft from the oregon today, thankfully. And figures in the low teens under tree cover : comparable to the legend hcx. Am yet to see single figure accuracy from the oregon 300 but I've only had it 3 days now...

[+Red90]

You can't compare the "numbers" on one device versus the other. They use completely different definition of "GPS Accuracy". To see if one is more accurate than the other requires comparisons to properly surveyed locations.

[+Jeep4two]

Find some benchmark disks in your area and see what you get. I've got one here locally that I use, it's a triangulation disk. I use the published coordinates and the latest beta release on the Oregon is within a few feet every time I go to the disk.

 

I really can't complain about accuracy - and I mostly ignore accuracy reading on the unit as long as it's less than 30 feet. If it's over 30 feet I start trying to make changes in how I'm holding the unit to get better signal.

[+Curioddity]

You can't compare the "numbers" on one device versus the other. They use completely different definition of "GPS Accuracy". To see if one is more accurate than the other requires comparisons to properly surveyed locations.

Exactly. The accuracy field in the "satellite-info" screen is basically meaningless as far as I'm concerned. I've lost track of the times that my Oregon 400t has led me right to the physical location of a USGS benchmark despite the fact that the device was showing an accuracy of 30-50 feet. It's also led me right to plenty of caches under trees or up against large buildings when the accuracy was showing 50-75 feet.

 

I no longer pay any attention to what that accuracy reading says anymore because it doesn't seem to really relate to how accurate the GPSr actually is. What matters to me is whether it leads me to where I want to go and marks accurate waypoints and it does that remarkably well.

 

Pete

[+Rifty]

Thanks folks. All very useful info. Happier now that it got me right to a cache this afternoon, gps accuracy showing as 20 feet but it was more like 3-5 feet !