Rediculously Extreme Accuracy?

[lotacus]

Just today, starting at approximatly 10am up to now (will check later in the day/night) I noticed something quite striking. I turned Location on in my Blackberry 8110 and refreshed the readings to notice that it reported an accuracy reading any where between 1.8 meters and as low as 0.9 meters. At first I thought this was probably a bug as I'm used to seeing anywhere from 3 meters up to 9 meters. I refreshed several times and walked myself to Tim Horton's. While there, I refreshed several times and the accuracy was still reporting as ~1 meter or less. I loaded up Google Mobile (which has GPS capabilites now! yay!) and started walking back home while watching it follow me using aireal maps. Even though GMM reported the location accuracy w/in 3m (probably the lower limit programmed by Google) Looking at my location on the map appeared to be extremely more accurate than what I was used to seeing. For example, before, it would show me as walking on the road when I was on the sidewalk, however, now it was showing me walking either on the sidewalk, or more accuratly as close to the sidewalk than before.

 

I still don't know if this is an isolated occurance or if it's just the positioning of the satellites at this time of day, but I've never had this much accuracy even with my Garmin GPSmap 60CSx. Unfortunatly I don't have that anymore to verify if it's just my Blackberry reporting the accurate readings or if other GPS devices are having the same wonderful luck.

 

A few things crossed my mind. Could it be the time of day? I ruled that out because i've never in years had a reading of 1 meter or less. Did they launch another satellite? Fix, tune, upgrade the satellites? Did the military still have some sort of degradation still imposed on the signals that they removed? Or could the Blackberry be including previous location information as part of it's calculation?

 

Now, I know you will probably ask how many satellites did it have a fix on? Well, the least amount of satellites was 5 the most 8, so that doesn't make any sense since I've had a fix on 10 many times with 6 meter accuracy, and last year a fix on 12 with my Garmin with 3meter accuracy. Oh, and AGPS has always been disabled because it is not even close to being as accurate as true GPS.

I'm located in St. John's Newfoundland Canada

 

So I would like to know if anyone is experiencing the same phenonema?

Edited May 18, 2008 by lotacus

[+moop]

Driving back from my friend's cottage in the Kawartha's to Toronto last weekend, I was consistently getting a reported accuracy on my GPSMap 60C of 1-2m. Sadly our schedule didn't permit me to stop for some caches along the way.

 

I have WAAS enabled and the satellite display showed differential adjustments on most birds. Typically I can expect a reported accuracy of 5+m.

 

Maybe GPS Control is preparing for the upcoming European competition.

[QuigleyJones]

For some reason my rino is generally 1 or 2m more accurate then my 60.

I attribute this to differences in the chip & firmware.

In your case its I would say its the above + the variability of the satellite constellation.

[+Tequila]

Guess I should get a Blackberry to go with my Colorado. Use the CO as the PDA and the Blackberry as the GPS.

[+ibycus]

Keep in mind that the reported accuracy may be calculated in different ways between models. One unit reporting 2m accuracy may in reality be just as accurate as another model reporting 5m accuracy (the difference being the confidence intervals etc that they put on their readings)

[lotacus]

Keep in mind that the reported accuracy may be calculated in different ways between models. One unit reporting 2m accuracy may in reality be just as accurate as another model reporting 5m accuracy (the difference being the confidence intervals etc that they put on their readings)

 

I dont know what it is but it just started happening today and I didn't update my blackberry software at all, and so far it is still reporting the same results.

 

but i'm definatly not complaining.

Edited May 18, 2008 by lotacus

[+peanutbutterbreadandjam]

Some GPS-enabled cellphones also supplement the GPS signals with cell-phone tower triangulation to improve accuracy, especially in areas where visibility of satellites is weak. Perhaps this is the case with your unit?

[+ibycus]

Keep in mind that the reported accuracy may be calculated in different ways between models. One unit reporting 2m accuracy may in reality be just as accurate as another model reporting 5m accuracy (the difference being the confidence intervals etc that they put on their readings)

 

I dont know what it is but it just started happening today and I didn't update my blackberry software at all, and so far it is still reporting the same results.

 

but i'm definatly not complaining.

 

I was more addressing some of the other posts trying to compare accuracy between units (i.e. comparing Rino to 60, Colorado to Blackberry etc). One would assume that within a given unit a more 'accurate' reading at least means *something*. (precisely what, we'll leave to the imagination).

[+hikerT]

I was caching on Friday in Caledon and put my GPS down to let it settle(magnetic micro on an old rail car). The GPS settled at 0m, which NEVER happens. The cache was less than 6 inches away.

[+PDOP's]

From GPSInformation.net a quote from a Garmin engineer:

 

EPE is an estimation, rather than a measurement, but all

measurable factors are used in the estimation algorithm. We

consider the details of our EPE and FOM calculations proprietary.

[lotacus]

well, it seems that late last night around 11:30pm and again today around the same time as yesturday when I got the really good readins, that these new readings now appear worse than they have. Now I'm getting poor accuracy readings from 12m to 37m 4-8 satellites. So something is going on.

 

I guess yesturday was some sort of fluke.

[+Taoiseach]

I was caching on Friday in Caledon and put my GPS down to let it settle(magnetic micro on an old rail car). The GPS settled at 0m, which NEVER happens. The cache was less than 6 inches away.

 

My GPSr put me within 2' (settled on 0.00') once - 'CANLOAN' - I'm impressed, as that was the final in a cache that required a projection!

 

As for accuracy, I had all of the satellites the other day and 5' accuracy :laughing:

[CharlieZulu]

Remember folks, we are in the hands of Uncle Sam, specifically the US Air Force. We'll never find out what's really going on, except that it's just going to get better and better. GPS IIR's continue to be launched, the GPS III contract was just announced (the US taxpayer gets to pay the whole $1.4Billion), and Galileo is still planned!