Navigation Satellite Systems

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Papa Legba
Joined: 25 May 2012, 14:07

30 Apr 2017, 00:29 #1

A footnote to your write-up on GNS systems: as well as being used in air traffic control, the Iridium constellation is now being marketed as a general positioning and timing solution. You can get a timestamp or a position fix from the Iridium system.

It's less accurate in both time and space, but has a couple advantages: much stronger signals, and more difficult to spoof. Stronger signals mean, of course, that it works further indoors, as well as being more difficult to jam. It's more difficult to spoof because there's a two-way link between ground and satellite, and the connection is encrypted. From what I can tell it's less useful for real-time navigation. I believe it requires a subscription, which no doubt the system owners like.

http://www.satellesinc.com/technology-2/
https://spectracom.com/resources/essent ... hat-is-stl
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gvgoebel
Site Admin
Joined: 19 May 2012, 11:33

30 Apr 2017, 20:47 #2

Oh dear, now I've got to update my GPS ebook again!

I'm up to 42 ebooks now. Alas, the more I write, the more time I have to spend on update and maintenance. They're much like software in that regard.

On the positive side, unlike a print book, I don't have to live with bugs -- and when somebody buys the ebook, they can download it again to get an update any time they like. Amazon.com has a option to make a paperback out of an ebook, but I'm not going to exercise that until I get something that sells at least one a day.
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Papa Legba
Joined: 25 May 2012, 14:07

03 May 2017, 19:19 #3

gvgoebel wrote:I'm up to 42 ebooks now. Alas, the more I write, the more time I have to spend on update and maintenance. They're much like software in that regard.

On the positive side, unlike a print book, I don't have to live with bugs -- and when somebody buys the ebook, they can download it again to get an update any time they like. Amazon.com has a option to make a paperback out of an ebook, but I'm not going to exercise that until I get something that sells at least one a day.
If it's any consolation, I bet it's as big a headache for the folks who have to work on extensive bibliographies. Does Amazon's ebook update routine have some sort of automatic timestamp for versioning? Also, I wonder when/if they'll ever make a complete version list available for, say, literary critics or historians-- tracking the life of a single work longitudinally could be interesting for certain fields.
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gvgoebel
Site Admin
Joined: 19 May 2012, 11:33

04 May 2017, 18:41 #4

> Does Amazon's ebook update routine have some sort of automatic
> timestamp for versioning?

Not that I've noticed. I keep a loose revision history at the end of each book, and also list current revision / release date at the end of the reader product description. Most of the time updates are just tweaky stuff -- like THE BOEING 727 & 737, which I've tweaked ten times since release, generally to describe new developments in the 737 MAX series and the P-8 Poseidon.

I have done fairly substantial changes to ENTROPY, INFORMATION, & THE DESIGN ILLUSION -- which might be subtitled "Creationism, Complexity, & The Paley Fallacy". I'm going to do another substantial update, mostly thanks to Dan Dennett and his discussion of the Conway Game of Life -- "Build Your Own Toy Universe And Watch It Evolve". Of course, I hardly ever sell any copies, but it's a good little book. I persevere.
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