Inaccuracy Today

[+Stump]

We did some caching today and until about 1 PM we had no problems. Then about 1 PM my GPSr just started acting crazy. I'd have plenty of satellites and good accuracy but it distance to cache would jump around from 10 feet to suddenly being .12 miles and then to 300 feet. Started to worry my GPSr was on the fritz after a few caches doing that but suddenly everything was fine. Went to one spot 3 times today, first 2 times it kept flipping out and the third time it zeroed out right at the cache. 100-200 feet from 4 or 5 spots it had zeroed out earlier.

 

Went to a known County Survey Control Point accurate to 5 decimal places and my GPSr matched almost perfectly (off .001) so it's working fine now.

 

Anyone else have problems today? Solar flares or something?

[+GeoRoo]

I wasn't out today, but did receive 6 e-alerts on geomagnetic activety in a 3 hour period. Conditions shot way up in a short time. The K index went from a relatively quiet 1 to 6 in one hour.

 

Suffice it to say the conditions were not favorable for HF propagation and no doubt this threw some curves in the GPS sats.

[+JavaDuck]

I had the same thing happen to me last weekend at a cache. My GPS said I was within 10 feet of the cache and then all of a sudden 12 miles then a little bit later .12 miles. I thought the same thing, that my GPS was on the fritz. I also showed an elevation of 5000 feet, I was only about 200 feet above sea level. Later that day, my GPS worked perectly and has worked good since then. Stange, huh?

[+Shop99er]

Mrs. Shop99er was have the same issues with her Garmin Saturday. On the other hand, my Magellan was working fine.....

[+EraSeek]

http://solar.sec.noaa.gov/rt_plots/kp_3d.html

 

Well that's why you use WAAS. Did you have it on?

[+Stump]

D'oh! Thought I did but I just checked and I had it turned off. Thanks for the reminder.

[+Pablo Mac]

I may be imagining things, but I occasionally experience situations like this where my receiver acts goofy and I later learn about a military operation happening at the same time. There have been at least a half-dozen times this has happened in the last year alone. I'm sure they have the ability to degrade the accuracy of the GPS as needed.

[Team Wallace]

My Magellan Map 330 had me at 11,450 feet above sea level and wildly off course (.5 mile north or so of actual location) this morning as I was driving through Issaquah (even with WAAS on)

 

got back to normal as I was heading up to Eastgate.

[+DJ Calamari]

My Sportrak Map was working fine until around 1 pm today, and I suddenly lost all satellites. I can't seem to connect to anything, I re initialized, cleared all memory, re uploaded the firmware. Still nothing. Did my GPS die? Any advice out there?

 

Nevermind, I fixed my GPS. My mistake.

Edited May 15, 2005 by DJ Calamari

[+Shop99er]

http://solar.sec.noaa.gov/rt_plots/kp_3d.html

 

Well that's why you use WAAS. Did you have it on?

OK, so I went and looked at the page linked here.

 

Very nice chart.

 

Now, will someone please explain, in English, not techno-babble, what that all means?

 

Please??

[+EraSeek]

Ok. Red is bad. Green is good. Red means lots of charged particles from the sun are hitting the Earths upper atmosphere and ionizing it causing a denser ionoshpere for the sat signals to pass through. This slows the signals.... and timing IS EVERYTHING to a GPS. One nanosecond (one billionth of a second) will cause a position error of (gosh what is it again) one meter ( or one foot). Thus during the day you always have a denser ionosphere than at night. During a solar storm you have a much denser ionosphere (red).

 

Here is a helpful link where you can learn a lot: http://www.windows.ucar.edu/spaceweather/sun_earth9.html

[+EraSeek]

Also here is a real time map: http://iono.jpl.nasa.gov//latest_rti_global.html

[+pdxmarathonman]

Thus during the day you always have a denser ionosphere than at night. During a solar storm you have a much denser ionosphere (red)

So then, caching is easier at night?

[+EraSeek]

Thus during the day you always have a denser ionosphere than at night. During a solar storm you have a much denser ionosphere (red)

So then, caching is easier at night?

Actually, in terms of gaining accurate coordinates, YES, all other things being the same such as sat geometry. WAAS will be helpful during the day but not so much at night, because there is little or no ionospheric corrections to be made. (however WAAS does still make some timing corrections)

[+EraSeek]

Why things happen you can see here: http://sohowww.nascom.nasa.gov/

Right now there are about 4 solar flares going on. One of them has aimed its cannon at us and fired! Increased activity is expected today and tomorrow.

 

So in my understanding, the sun shoots these charged particles at us, and they and the utraviolet light ionizes the upper atmosphere on 2 levels. In addition to this there is a bow wake effect of the atmosphere, compresing it. Some of these charged particles find there way past our protection in a sort of magnetosphere hole at the poles. These charge particles ionize hydrogen and nitrogen and oxygen molecules causeing the varying colors we call the northern lights.

In addition to this, some of our radio broadcasts are disturbed by this heavy solar wind and does not bounce off the upper atmosphere as normal, but punches through the atmosphere and thus we have lousy tv and radio reception.

 

Things are not a calm sea anymore. I was able to witness this directly once in an increadible auroral display. I could literally see the upper atmosphere sloshing back and forth as if I were in the bottom of a very active fish bowl. I thus understood for the first time how dymanic the atmosphere really is!

[+EraSeek]

Here I go again... forgive me, I get involoved in this stuff and it is hard to shut me up. But..

 

Here is a really cool, REAL-TIME image of the Earth's magnoshpere and the bow shock wave from satillite data above the north pole: http://pixie.spasci.com/DynMod/

 

(Hmm, the date on the graph shows 4/30/2005 ?)

Edited May 15, 2005 by EraSeek

[+EraSeek]

OK maybe not Geocaching related but how good are you at launching your own satillite> Just click your mouse.

http://www.colorado.edu/physics/2000/applets/satellites.html

 

Have fun!