Absolute GPS accuracy?
 

When I use an application like GPSLogger on my 8330 it shows estimated position errors of about 50 feet. This is fine for navigation with software like Garmin or Telenav. But I also have a WAAS enabled GPS that shows a position error to within (sometimes) 6 feet, which is great for geocaching. Does anyone know the best accuracy you can expect out of BB GPS? I am guessing it is not WAAS enabled. There is no information online that I can find.

Accuracy is all based upon selective availability as established by the US Dept of Defense. They basically control the accuracy of the signals. It just depends on how big a circle is set up.

Best I have seen so far is 4 meters, but generally under 10 is what I get. Up until a few years ago, the best you could expect was that you'd be somewhere within a 40 meter circle. Now its more like a 10 meter ellipse.

Don't think there can be anything such as an absolute accuracy however.

It's also dependent on the capabilities of the receiver. A WAAS enabled receiver will use both satellites and ground stations to correct its position giving better accuracy. I have not found any information on the Blackberry and whether it can use the WAAS system.

I have a Garmin bluetooth receiver that my BB can use and it is WAAS enabled. I think I will perform an experiment this evening and see if my accuracy improves when I use it. 8-)

Selective Availability was turned off in 2000. Without enhancement like DGPS, WAAS or LAAS the best you can expect from a commercial GPS device is 2 to 3 meters. Actual position accuracy will be degraded from that figure by anything that introduces propagation path delays such as changes in the Ionosphere, foliage, buildings or vehicle structure.

So the question remains basically, is the BB WAAS enabled? I suppose if it were it would say so somewhere.

Selective availability is still there. You just never know when and where it is activated. It is always an option. I really question 2 - 3 meter accuracies as well.

AFAIK, it is not.

Thank you - I thought that was the case. For the sake of completeness (and because I am a geek!) I am going to compare the position errors between the built-in GPS receiver and my Garmin bluetooth receiver (WAAS enabled) and see what it turns out to be.

Want it to appear here? :)

I would be curious to see the results. You must keep in mind that we need to compare apples to apples.

OK, I am going to try this again at home. I just did a real quick check in the parking lot here at work :)

Using GPSLogger on my 8330, using the built-in GPS I am seeing a reported position error of 65' lat, 39' long. It sees 7 satellites. I let it settle for a few minutes before noting the readings.

The Garmin eTrex Venture HC is reporting a position error after settling for 5 minutes of 20'. I have seen it as small as 6'. It sees 12 satellites.

I switched to the bluetooth Garmin GPS 10X on the BB 8330, again using GPSLogger. It reports a position error of 2'! Whoa! It also sees 12 satellites.

All the instruments were in the same position under and open sky. No trees, buildings or anything to interfere with GPS. It is a clear calm day here in northern Ohio :)

OK, a little more detailed info;

Curve 8330, GPSLogger, open field, 5 minutes to settle in;

41deg 25m 32.27s
81deg 30m 13.90s

8 satellites

Error of 44 feet.

Curve 8330, Garmin GPS10x Bluetooth GPS,

41deg 25m 32.02s
82deg 30m 13.33s

8 satellites

Error of 3 feet.

Garmin eTrex Venture HC - WAAS turned on.

41deg 25m 32.0s
81deg 30m 13.6s

12 satellites

Error of 14 feet.

What the absolute accuracy is, I don't know since all I had for my position was the GPSs I was testing - no reference point. But they are all reading pretty closely together. I am sort of shocked at how close the GPS 10X is reported as being. I don't know if it actually IS that close.

All units were within inches of each other.

Where are you finding the error listing in GPSLogger?

Wirelessly posted

The data is between the square braces at the top of the page.

Wounder if it is possible to use loki and wifi for greater GPS accuracy

Don't see how Wifi could help. What is loki?

Waas
 

LOL......Are u a Pilot? (y)

Wirelessly posted

Nah. I wish. Mostly its fascinating tech :)