The GPS unit on my boat regularly claims an estimated position error of 4
feet after it has acquired its full complement of satellites. This is a
fairly new mid-price GPS unit using up to nine satellites and WAAS. So my
recreational GPS supposedly obtains fifth-decimal-place accuracy. It was
running under an unobstructed sky, which is common when boating. Careful
use of a good GPS unit should be able to achieve this level of accuracy on
land as well.
gps/performance/accuracy/the raw accuracy
of the positioning information from a satellite is less than 2.4 feet 95% of
the time. The accuracy reported by a GPS unit is degraded by atmospheric
conditions; false signals, e.g., bounces; and the need to determine position
by intersecting the raw data from several satellites. Accuracy can be
improved by using more satellites and multiple frequencies and by
comparing to a signal from a receiver at a known location.
The web page above claims that accuracy can be improved to a few centimeters
in real time and down to the millimeter level if a device is left in the
same place for a long period of time. I think that these last two
accuracies require a close-by receiver at a known location and correspond
to what is said in .
On 08/30/2017 06:53 PM, Nick Wilson (Quiddity) wrote:
> On Tue, Aug 29, 2017 at 2:13 PM, Stas Malyshev <email@example.com> wrote:
>> [...] Would four decimals
>> after the dot be enough? According to  this is what commercial GPS
>> device can provide. If not, why and which accuracy would be appropriate?
> I think that should be 5 decimals for commercial GPS, per that link?
> It also suggests that "The sixth decimal place is worth up to 0.11 m:
> you can use this for laying out structures in detail, for designing
> landscapes, building roads. It should be more than good enough for
> tracking movements of glaciers and rivers. This can be achieved by
> taking painstaking measures with GPS, such as differentially corrected
> Do we hope to store datasets around glacier movement? It seems
> possible. (We don't seem to currently
> I skimmed a few search results, and found 7 (or 15) decimals given in
> one standard, but the details are beyond my understanding:
help/9.3/arcgisengine/java/gp_ toolref/geoprocessing_ environments/about_coverage_ precision.htm
questions/1947481/how-many- significant-digits-should-i- store-in-my-database-for-a- gps-coordinate
questions/7167604/how- accurately-should-i-store- latitude-and-longitude
questions/8650/measuring- accuracy-of-latitude-and- longitude
Wikidata mailing list