[OSM-talk] Strange location reading

[Michael Collinson]

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