Yet Another Cycling Forum

General Category => Audax => Topic started by: Exit Stage Left on 12 August, 2017, 10:24:18 pm

Title: [LEL17] Sunspots and GPS.
Post by: Exit Stage Left on 12 August, 2017, 10:24:18 pm
I'd arranged some drone filming on the Whorlton Bridge to Alston section. The operator will cancel the filming if the conditions are unsuitable. So I was apprehensive as I approached Teessdale, and the wind was blowing.

I contacted Andy at Hovershotz from Pocklington, he thought his equipment could handle the wind. I was using YR.NO for my forecasts. Andy was using a dedicated drone forecast. His main reservation was that forecast sunspot activity might interfere with the GPS which drones use to hold station. I didn't resolve my anxiety about the drone filming until I saw the results on returning home, which were good, which given the conditions, was excellent service.

I do wonder if anyone had any strange GPS problems though. There are space-weather sites which forecast this stuff. http://www.metoffice.gov.uk/public/weather/space-weather/

Route-sheets remain unaffected.
Title: Re: Sunspots and GPS.
Post by: frankly frankie on 13 August, 2017, 10:11:10 am
Googling it, although there obviously is an effect on the GPS system when solar activity is high, there seems very little agreement on what the problem actually is.  I suspect simple interference with the signal strength is the most likely problem, because the GPS transmissions are incredibly weak anyway (something like 50 Watts from a minimum of 12600 miles away, and received using a non-directional aerial so vulnerable to noise).  Other possibilities seem to include altered speed of transmission through the ionosphere, and solar wind interfering with the satellites directly.  If these latter last any great length of time then some self-correction takes place within the system.  Plus there are currently far more than the specified 24 satellites in active service, offering some redundancy.
In any case GPS is a whole magnitude more accurate than a road cyclist really needs (and if you're riding over Yad Moss, several magnitudes really, there's little scope to go wrong) so a temporarily reduced performance shouldn't pose a problem for cyclists.  Drones, another matter.
Title: Re: Sunspots and GPS.
Post by: Kim on 13 August, 2017, 10:34:10 am
Drones are a lot more reliant on an accurate elevation reading than cyclists.  By design, GPS sacrifices elevation precision for latitude/longitude precision, and it tends to suffer more when things get a bit marginal.
Title: Re: Sunspots and GPS.
Post by: Jacques on 13 August, 2017, 01:19:10 pm
My GPS (Edge 810) threw a wobbler in exactly the same place going over Yad Moss (near the traffic lights) out and back. Both times it locked up and started beeping at me, only way to get it going was to reset it.

At the time I blamed the sheep but maybe after reading this thread who knows?

Title: Re: Sunspots and GPS.
Post by: The French Tandem on 13 August, 2017, 08:24:18 pm
... going over Yad Moss (near the traffic lights) ...

Traffic lights over Yad Moss? I must have missed something! You may be talking about the traffic lights in Barnard Castle, just before the beginning of the climb?
Title: Re: Sunspots and GPS.
Post by: Deano on 13 August, 2017, 08:47:15 pm
They're rebuilding the road at the summit so there are temporary lights at the Cumbria/Durham border.
Title: Re: Sunspots and GPS.
Post by: Greenbank on 14 August, 2017, 10:23:15 am
Temporary traffic lights often emit loads of crap over the RF spectrum. I've had various problems in the past with GPSes when passing some of them.
Title: Re: Sunspots and GPS.
Post by: Pip on 14 August, 2017, 02:11:30 pm
My GPS (Edge 810) threw a wobbler in exactly the same place going over Yad Moss (near the traffic lights) out and back. Both times it locked up and started beeping at me, only way to get it going was to reset it.

At the time I blamed the sheep but maybe after reading this thread who knows?

Had exactly the same problem. Garmin 810 froze, only two bits of ride missing were both ascents of Yad Moss
Title: Re: Sunspots and GPS.
Post by: jochta on 14 August, 2017, 02:31:17 pm
My GPS (Edge 810) threw a wobbler in exactly the same place going over Yad Moss (near the traffic lights) out and back. Both times it locked up and started beeping at me, only way to get it going was to reset it.

At the time I blamed the sheep but maybe after reading this thread who knows?

Had exactly the same problem. Garmin 810 froze, only two bits of ride missing were both ascents of Yad Moss

(http://i0.kym-cdn.com/photos/images/facebook/000/158/329/9189283.jpg)
Title: Re: Sunspots and GPS.
Post by: Exit Stage Left on 14 August, 2017, 07:11:22 pm
The 'Golfball' on top of Great Dun Fell houses an air traffic control radar. That may affect some GPS's. It has a range of 250kms, so the signal is pretty powerful in close proximity.
Title: Re: Sunspots and GPS.
Post by: frankly frankie on 14 August, 2017, 11:29:26 pm
That sounds plausible.  Subsequent to my prevous post
Quote from: ff
... because the GPS transmissions are incredibly weak anyway (something like 50 Watts from a minimum of 12600 miles away ...
it seems (Wikipedia thobut) that the transmitters are under 30 Watts. Incredible really.
Title: Re: Sunspots and GPS.
Post by: Exit Stage Left on 15 August, 2017, 07:45:26 am
We've had problems with controlling a drone near power lines, transformers, and especially traffic lights.