Sun spots may stuff your satnav

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Posted: Wed Feb 10, 2010 9:37 am

As a one time radio ham, I know about the 11 year sunspot cycle. Last time we had a solar maximum we didn't have satnav everywhere, this time they will be going blind and miscalculating.

When a plane lands in my garden I'll know who to blame. It could be a good excuse to send your safari lad to the wrong place though. Wink

BBC Article

Quote:

Bob Cockshott, a director of the government-funded Digital Systems Knowledge Transfer Network, said that for most consumer applications such as sat-nav for cars, the problem will be more troublesome than dangerous.

"You might find for a number of hours or even a day or two you couldn't go out surveying or be able to dock your oil tanker at the deep-ocean oil well," he told BBC News.

That's all right then, its when your car tries to dock at the deep sea oil well you worry.

Posted: Wed Feb 10, 2010 10:45 am

^^^Any one want lessons on how to read a map Laughing

Master of Master Baiters Joined: 26 Sep 2008 Posts: 689

I knew I should have hung on to that "Readers Digest Book of the Road" (only £29.95+p&p with a life time subscription to Readers Digest)

and all me old OS maps ....

Wink

Posted: Wed Feb 10, 2010 8:33 pm

"Bob Cockshott"? That can't be a real name!

Posted: Thu Feb 11, 2010 4:38 pm

^^I had the same reaction as Bohigal. I think the BBC is baiting you.

Posted: Thu Feb 11, 2010 6:18 pm

Sunspots don't cause much problem most of the time. I've been geocaching for a long time and worked with marine nav long before that. The sumspots are not much problems in themselves. The issue is CME's. If a powerfull one is directed our way (Most are not) is is possible for a temporary blackout. This is rare and rarely lasts more than 24 hours. Many of them take at least 8 hours to arrive, so before you fly, check with your airport for any active CME. The SOHO satellite is watching for these.
http://sohowww.nascom.nasa.gov/

For critical nav the article simply omitted all reference to differential GPS. Differential GPS uses a GPS receiver at an airport or other fixed location and then measures the local error and transmitts it. A plane or survey crew (both use it) receives the GPS signal and the local error and then can produce a fix in the sub meter range. In survey equipment with a long sample time, sub centimeter accuracy is common. Picking where you land on a dollar bill is good enough for me.
http://www.esri.com/news/arcuser/0103/differential1of2.html
http://en.wikipedia.org/wiki/Differential_GPS

Total loss of GPS signal in a CME is about the only issue remaining. A little degradation is already corrected if you use differential GPS. CME events can be seen and their arrival planned for in advance much like avoiding flying through a hurricane. We see them coming. Light from an ejection arrives in about 8 minutes. The mass arrives much later.

Knowledge replaces fear.

Baiting Guru Joined: 31 Jan 2007 Posts: 12237

@Roycropper

This sounds like a good excuse to warm up some tubes, and fire up LORAN again. Very Happy

Posted: Fri Feb 12, 2010 1:00 am

Never had any luck with Loran and I know that they are off all the time for solar activity, at sunrise, sunset and at night. Just before a licensing check ride I noticed that someone had squawked the Loran unit and it had been red tagged. I asked the FAA examiner what I should do. He told me he hated them also. I think the last time around the GPS signal was intentionally degraded so I saw no change in performance. Bill Clinton signed some bill authorizing higher resolution later on. This time around two of our cars have DR or dead reckoning, picking up information from the odometer and an electronic compass and inertial guidance using Murata piezoelectric vibrating gyroscopes as a back up to GPS signals so they don't be affected at all. Makes getting lost coming home from work pretty hard.

Posted: Fri Feb 12, 2010 3:17 am

Quote:

This time around two of our cars have DR or dead reckoning, picking up information from the odometer and an electronic compass and inertial guidance using Murata piezoelectric vibrating gyroscopes as a back up to GPS signals so they don't be affected at all.

It's what they are using on sub-marines.(almost)

What I heard (I'm also in the survey business) is that there working on mix between GPS and Loran-C. In a way that you can get a fix by a combination of both systems. Loran-C is a reliable system (depending the purpose and location) but in my opinion it was always a pain in the @ss to configure it correctly.

Galileo (European version of GPS) would also get you a kind of back-up but the big disadvantage of that is that it uses almost the same frequency as the US GPS system. But the unique thing about that system that they will give you a guarantee on your position (paid system)

Posted: Fri Feb 12, 2010 4:46 pm

I had a dinner party guest over at Christmas that worked on sub inertia guidance. I told him I had read the user's manual for the SINS (ship's inertia guidance) as used on the carrier USS Midway just for giggles and grins. Its a museum piece and not classified. He asked if the SINS was a cylinder about the diameter of a torpedo. Yes it is. That's so it can enter a sub as a torpedo he says. I ask if the new systems use ring laser gyros. No confirmation of course. Craig007 jockeys the Airbus A320s that use RLGs for navigation.

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