GPS...

[petermcleland]

I was wondering if that cruise ship that went aground was locked onto a GPS track...This is what made me wonder:-

http://www.bloomberg.com/news/2012-01-1 ... ution.html

I have noticed a wandering of my GPS fix recently!

[Paul K]

Interesting thought, Peter.

[jonesey2k]

It does beg the question. How the f$%@ does a 21st century ship that is barely 6 years old stray so close to the coast and how does it sustain enough damage to sink it?!

[Garry Russell]

B ear in mid sand banks shift

He was very close, too reliant on gadgets??

[jonesey2k]

They are saying the ship was 4 miles off course. And I don't think it was a sandbank as there is a rock the size of a bungalow sticking out the side of the hull!

[airboatr]

LightSquared say the GPS manufactures should have made allowances for their transmissions over frequencies that are close to those used for GPS.

They have an investment of roughly 3 billion in a network that causes interference to those used by GPS, hmmm

And they did a small test in the beginning to see if their system would violate FCC rules ..... by causing interference to other equiptment using radio waves?

oh boy... someone's goona have some splainling to do

Years ago I managed a Radio Shack about 12 miles north of KPBI just a mile inland. One day a van with a slew of aerials was driving around in the parking lot for about 5 minutes and then made it's way to my store. These guys get out of the van and walk through the door stating they have a complaint from the FAA that interference is being broadcast and they've traced it HERE. I said, "I don't have any CB's or walkie talkies on". But they weren't looking for that sort of stuff. "it's television!".
Really? Well thats odd.
Then they say that antenna boosters and FM boosters are what they want to look at. So they unhooked some things and went and did a test, came back awhile later and said it was all good. then wrote me a receipt for the boosters and took them!



Then I have to get on the phone and telll the district manager, and he's asking me what I did, And I'm like ,
It wasn't me that done it

[SkippyBing]

LightSquared are unlikely to affect a GPS in the Med, line of sight and all that. Someone putting the wrong Lat/Long into the AutoHelm...

[Chris Trott]

LightSquared say the GPS manufactures should have made allowances for their transmissions over frequencies that are close to those used for GPS.

I still love this assertion. GPS manufacturers should have made allowances to protect against a signal more than 100x more powerful than allowed by the FCC/NTIA Spectrum Allocation and should have done so when they developed the GPS system almost 30 years ago. The problem is that their bandwidth control isn't sufficient to prevent "bleeding" into the adjacent spectrum and there is no real way to prevent interference from occurring when your signal is that much stronger than the ones in the affected spectrum.

As it is, since LightSquared is the one who's wanting to deviate from the Spectrum Allocation, they should be the ones putting up the money to "fix" all the GPS devices, not the GPS manufacturers and users (including the US Government) who've already invested many, many times as much as LightSquared over the last 30 years.

I was wondering if that cruise ship that went aground was locked onto a GPS track...This is what made me wonder:-

http://www.bloomberg.com/news/2012-01-1 ... ution.html

I have noticed a wandering of my GPS fix recently!

Your wandering GPS fix wouldn't be from LightSquared. They only have 1 satellite in orbit at this point, it's over the US, and it only transmits during their tests which they have to make announcements about over a week in advance. It's probably either due to selective availability periods (i.e. the US military purposely degrading the accuracy of GPS available to non-government users) that can occur for many reasons including just to test it (which they usually notify aviation users for) or that your local WAAS station (which allows for the great accuracy needed for vehicular GPS to work well) is suffering problems (not unusual either).

[petermcleland]

Thanks for that explanation Chris...I didn't know that selective availability was still used. I was under the impression that it was permanently switched off some years ago.

[Paul K]

It does beg the question. How the fuck does a 21st century ship that is barely 6 years old stray so close to the coast and how does it sustain enough damage to sink it?!

My understanding is that the current location of the ship is not where it originally struck the rocks. After it started to flood they headed for shallow water, where it capsized. I might be wrong, but that's the impression I get. Thats a bloody big gash down the side; way beyond the capacity of the ship's pumps to deal with.