Solar Flares and GPS

[TXS-ALAMO]

The Associated Press has just released a report today, 4-4-07, that a solar flare on December 6th disrupted satellite GPS signals and prevented some receivers from locking on. They say that the aviation WASS stations did overcome most of the problem. However, they say the only way to stop disruption of the GPS system is to modify the satellites or the antennas on the receivers. The solar flares are cyclical and are expected to increase in numbers and intensity through 2011. Don't throw away that old sextant!

[Cruisingdad]

Well, that explains why I hit the dock that day. Damn GPS went out. Good, now I have an excuse.

- CD

[Sabre66]

I'm surprised that doesn't happen all the time. GPS signals aren't very strong.

Last year I was coming in from a race, in the dark, when a thick blanket of fog overtook us. I pulled out the GPS but it was giving me a very strange route back to the mooring as in 180 deg off. I laid out a paper course from the last can we saw on our stern and we made it in. Later I found out that the map datum had switched itself to some weird Asian format that didn't agree with our charts. Still trying to work it out, it's a high end GPS but I'll never trust it, entirely, again.

[btrayfors]

I don't think we "use GPS with great caution, and only as a supplement to other nav aids" guys are ever gonna convince those who believe that GPS is accurate 100% of the time.

But stories like these may put just a dent in their consciousness.

This story from Cornell researchers should be a wakeup, too, in re: solar flares...

Solar flares cause GPS disruptions

One of the outages they observed lasted 15 minutes....quite long enough to cause a major disaster if you're depending only on GPS nav data.

Bill

[tenuki]

I have two GPSs, one handheld usually out in the cockpit that I use for an absolute speed indicator (lots of strong currents here) and the other a usb magnetic mount connected to my laptop and charting software. They are firmly secondary nav aids as I have a paper chart that I rely on as primary. Since all of my navigation to date is in puget sound I nav with mupltiple fixes (generally easy to find here) on the paper chart, then cross reference with the nav software. If there is a problem I can consult the other GPS and troubleshoot from there. Haven't got offshore yet, but next year I'm wanting to circumnavigate vancover island, so sextant here I come.

I still look at manual navigation as fun, I think that primarily informs my method, not safety.

Anyone have recommendations for beginner sextants? The math doesn't scare me (to tell the truth it attracts me ), but don't know anything about the equipment.

Thanks for providing me with an excuse to get a sextant TX.

[sailingdog]

Sabre-

The GPS satellites only broadcast at 50W or so.

[sailingdog]

Tenuki-

Go out and get a decent metal sextant. Then get the book, The Complete On-board Celestial Navigator, 2004-2007 edition.

And have fun.

[Sabre66]

40 to be exact...or so I'm told.

[sailaway21]

Tenuki,
I am under pain of death if I mention the cele.... words on here. My advesary is a very powerful individual with a thin skin. I can advise you to 'search' the forum archives under sextants and celestial. There is a tremendous amount of information there-as in "it'll make your eyes glaze over", with sources for moderate priced as well as professional grade sextants.
As far as reading material goes, here's your chance to buy a copy of Bowditch. No mariner should be without one.

[tenuki]

make sense, those satellites are solar powered, right?

[ducks and runs before the solar madmen start mobbing this thread too]