Monday, April 4, 2016

Gotta Love That GPS

So, I was out and about earlier today and tried to use my phone to determine my location. I discovered it could not get an accurate fix.

Hrm.

So, I changed it to "Device sensors only" and couldn't get a fix at all.

I couldn't get a GPS signal. We rely on GPS a lot these days.

GPS - Global Positioning - is dependent on a GNSS network - a whole bunch of small satellites in orbit. It broadcasts on two frequencies - L1 and L2. Your phone uses L1. L2 is reserved for the military.

So, why couldn't I get a signal?

One reason is the so-called urban canyon - tall buildings can block the satellite. There weren't any tall buildings around, so, move on. I also wasn't underwater.

Could be another signal? Nope, I moved far enough that anything local wasn't interfering.

Most likely? It was the sun's fault. Space weather. According to spaceweather.com, a solar stream hit us on April 2nd and another one is due tomorrow. While the sun is relatively quiet - I suspect there was some upper atmosphere magnetic activity my poor phone didn't like. Ah well. Fortunately, I can navigate perfectly well without it. (Although I couldn't play Ingress, drat it).