Sat Nav and the Zombie Apocalypse

[alchemist]

Okay, it's not actually a zombie apocalypse, but it's the same principle; all the infrastructure is there but there's nobody to look after it.

Post-apocalypse, how long could a car's sat nav still work for? As the satellite is orbiting, oblivious to all the death and destruction, I presume it'll keep doing its job until sufficient software glitches occur to change that. So will my MC's device still work two months after the event?

 

[ctg]

Yes, I believe it should be working as long as there's batteries left and to be honest, I don't think most of your readers would care about factual evidence as there is also the Russian and European system in the market. However further the time goes more errors start to creep into the system as some of those satellites fall out from the orbit etc. So eventually your MC should learn to read maps, compasses and nature.

 

[alchemist]

So eventually your MC should learn to read maps, compasses and nature.

Dunno, she's a woman *runs away cackling*

Cool, it'll work after two months. The story only happens over the course of a few days so I don't have to deal with the whole rebuilding of society stuff. Thanks!

 

[Jo Zebedee]

Cheeky... So, will we see humourous driving into the ford not marked scenes. Since that's basically all mine does in this neck of the woods anyway.

A couple of thoughts - presumably after the apocalyspe road building stops? So the data shouldn't date? But, also, it can't make allowances for roads degrading etc. depending on time of year, this might be signifcant. Battery wise, can't they recharge from the car? I'm sure mine - the one i never use cos i text friendly locals instead and act like a helpless woman - came with a plug in to the lighter-socket attachment.

 

[alchemist]

Yup, mine charges in the car too. I'm not planning too much road degradation in that timescale, but there will be ..... unexpected blockages.....

 

[ctg]

To be honest unless your characters are complete dumps they should learn all sorts of inventive ways to generate electricity without using muscle power. And if you let them, who knows your MC might turn up to be a female version of Mr Grylls.

 

[Glitch]

Don't the newer ones try to update based on traffic data? A lot of stationary cars could confuse the system!

 

[alchemist]

Don't the newer ones try to update based on traffic data? A lot of stationary cars could confuse the system!

Mine doesn't (I'm too cheap!) but if it did, where does it get the data from? Other satnavs (which will be dead) or plain old satellite imagery?

 

[Glitch]

Mine doesn't (I'm too cheap!) but if it did, where does it get the data from? Other satnavs (which will be dead) or plain old satellite imagery?

Mine doesn't either, but that's besides the point.

I believe they work via the mobile phone network. They may all be dead, but assuming enough power to keep them going for a few hours might be enough to update a central server somewhere. If your sat nav hasn't downloaded data since, it could still assume there was a traffic problem

 

[alchemist]

Hmm. Most of my blockages should be non-car related, but it's still good to know. Thanks, Glitch.

 

[Gumboot]

Okay, it's not actually a zombie apocalypse, but it's the same principle; all the infrastructure is there but there's nobody to look after it.

Post-apocalypse, how long could a car's sat nav still work for? As the satellite is orbiting, oblivious to all the death and destruction, I presume it'll keep doing its job until sufficient software glitches occur to change that. So will my MC's device still work two months after the event?

I don't think it would last long at all. The problem is that GPS consists of three elements. In addition to the satellites and receivers, there is also a control element. This monitors the satellites and constantly updates their orbits and resets their atomic clocks, because both have to be very accurate for the system to work. This is done manually, by US government agencies.

As soon as the control element is removed from the equation the system falls apart because the satellites will begin to track out of orbit and lose timing. These would very rapidly lead to wildly inaccurate GPS readings.

 

[alchemist]

So, new info. Thanks Gumboot. Any idea how long before it would pack in? I appreciate they probably didn't factor in a zombie-like apocalypse when setting the system up.

To tell the truth, the no satnav scenario probably suits my story a little more, but I can easily work around both.

 

[Glitch]

The satellites would probably still transmit a signal even if they were out of position. The sat-nav could then get its position wrong.

 

[AMB]

QI suggests satellites would be out 38,000 nanoseconds per day, at 1ft per nanosecond.

Sadly, I did just happen to hear that and rush to write it down.

 

[Glisterspeck]

... I appreciate they probably didn't factor in a zombie-like apocalypse when setting the system up.

You never know. The CDC, for their part, are well prepared.

http://blogs.cdc.gov/publichealthmatters/2011/05/preparedness-101-zombie-apocalypse/

 

[BetaWolf]

The satellites would probably still transmit a signal even if they were out of position. The sat-nav could then get its position wrong.

That sounds like a plot point in itself. So, a tax accountant survives the end of the world, and she doesn't realize that her sat nav is totally off, due to orbital decay, etc. According to the little flashing map thingie, Paris is located somewhere in Siberia, and Moscow is in the middle of the Pacific Ocean. Finally some kid tells her otherwise. Two chapters later, she starts to believe him.

 

[Ursa major]

...just before debris from a falling satellite hits the spot where she's standing, killing her.

 

[Glitch]

...just before debris from a falling satellite hits the spot where she's standing, killing her.

Brings new meaning to - you have reached your destination