Well worth visiting
Well worth visiting and supporting for anyone with a history in either computing or indeed electronics of any sort.
13 posts • joined 7 Jun 2017
Every 10+ year old BS that we use has an external "professional level" GPS device to maintain the long term RF clock accuracy, we don't care about the time/date.... But still they all reported errors the first time this happened, but likely they've all been swapped out for newer by now... I hope... :)
Well, back in the day... Moto won the original Airwave contract because they committed to introduce AIE (Air Interface Encryption) to a timescale which Nokia, the only other contender, who in fact initially won, would not commit to. They then used AIE with fixed keys, and only changed this much later, whereas Nokia went straight to (imho) proper AIE in one step (but took longer)...
Guys, guys... I've been going down though this thread...
Its true that all the mobile phone system masts (or at least the systems I am familiar with!) use GPS as a clock reference (but usually not primarily as a time reference, they use it to maintain clock accuracy). So what happens when its jammed? Well nothing, really. The clock accuracy starts to degrade. On the kit I am familiar with, it will take 6 MONTHS to a year for anything to shift enough to matter. I routinely see GPS fails on TETRA or GSM sites, its not critical.
It's pleasing to see that we are managing to preserve this, I visited NMOC myself a year or 2 back, it's well worth it imho. Flowers, Turing and the (many) others that did some astonishing things deserve the recognition as well! Jack Copeland has an interesting book on Colossus, well worth a read imho.
"I'm having extreme difficulties trying to imagine a scenario in which rescue workers within 17 metres of a person in distress are having major difficulties locating it. Sure, more precision is always a good thing, I just don't see it making much difference in that case (let alone for any aircraft - I don't think any of them is expected to fly within 17m of any treetops...) ..."
Errr well, how about a burning building, person on the other side of a wall? Or ditto & add smoke... High precision is wanted for aircraft as well, because then GPS can be used for navigation (proper, airplane navigation). That is one of the things Galileo is supposed to bring, it should have sub-1M accuracy, allowing you to e.g. land a plane with it.
Phone GPS chipsets are spec'd basically for US accuracy level GPS, i.e. not very...
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