On 28/09/16 09:59, Warin wrote:
On 28-Sep-16 04:44 PM, Oleksiy Muzalyev wrote:
On 27.09.16 21:51, John Eldredge wrote:
This past weekend, I made a long road trip. At one point, while in a
highway rest stop, I checked Google Maps to see how far I had come.
To my surprise, it showed me at a different rest stop, about 200
miles from my actual location. I suspect that my phone couldn't get
a good GPS reading, and was relying on the WiFi ID from the rest
area office. The other rest area was probably using the same SSID.
I didn't think to launch OSMand for comparison, but I suspect it
would have given me the same bogus results, as the choice of whether
to use WiFi, cell tower, GPS, or a combination, to determine your
location is set in the system settings, not inside the mapping
applications.
GPS signal is not influenced by clouds, rain, and snow. The GPS
signal frequency of about 1575mhz was chosen expressly because it is
a "window" in the weather as far as signal propagation is concerned
[1]. However a coating of water, snow, or ice on a smartphone or on a
car may block GPS signal. A coating of water, even a fairly thin one
is NOT the same as raindrops.
So if one is outside and a device is dry, the GPS reading should be
correct no matter what is the actual weather. Otherwise it makes
sense to restart the device, or change it if an incorrect GPS
location reading persists.
John .. could you have the GPS function on the phone turned off? I
usually have mine turned off to save battery power .. for use as a
phone. There is a GPS Status app that I use to check various sensors
.. including what the GPS is doing, suggest you use it .. that is an
android app ... apple should have something similar.
Do these rest stops have cafes that are part of a chain? They might have
moved a wifi access point and your app is reporting a non-satellite
position based on that. I have seen that happen.
Mike
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