Scenarios for losing GPS/GLONASS/Galileo constallations: are they plausible?

[JPA Cate]

There is greater concern about spoofing. Some navlist-ians advocate taking a daily celestial site to cross check the GPS and confirm that it isn't being spoofed.

This has been an interesting discussion. I wanted to say that developing the above practice will help you "keep your hand in", keeping your muscle memory going, all the coordination factors needed when doing celestial from a small bouncy "platform".
And, however you choose to do the sight reductions, practicing daily will make the mental processes more smooth, too.

Ann

[zboss]

Again... your phones will still work with cell phone triangulation only, although the accuracy is in the miles. Very shortly, new timing chips that have the necessary accuracy are going to replace the existing systems and that accuracy will go to about what we now achieve with satellites but using terrestrial antennas only. On top of that, the signal strength is so strong there is very little chance of the signal being interrupted by foreign actors. In addition, the opening of the old TV white space frequencies for cell phone use has boosted the range of cell service significantly, especially with the new round of phones that utilize the 600 MHz frequency with T-Mobile. It has a range twice as far as the higher LTE frequencies. So yeah, if you are out in the middle of the ocean you will need to use a compass and dead reckoning or the sun but within 5 years once you get cell service you will be able to use differential gps on the phone.

[SeanPatrick]

Originally Posted by Jammer

There is greater concern about spoofing. Some navlist-ians advocate taking a daily celestial site to cross check the GPS and confirm that it isn't being spoofed.

One member has developed an app specifically for that purpose:


https://play.google.com/store/apps/d...k.GPSAntiSpoof

[Cpt Pat]

Originally Posted by zboss

Again... your phones will still work with cell phone triangulation only, although the accuracy is in the miles. Very shortly, new timing chips that have the necessary accuracy are going to replace the existing systems and that accuracy will go to about what we now achieve with satellites but using terrestrial antennas only. On top of that, the signal strength is so strong there is very little chance of the signal being interrupted by foreign actors. In addition, the opening of the old TV white space frequencies for cell phone use has boosted the range of cell service significantly, especially with the new round of phones that utilize the 600 MHz frequency with T-Mobile. It has a range twice as far as the higher LTE frequencies. So yeah, if you are out in the middle of the ocean you will need to use a compass and dead reckoning or the sun but within 5 years once you get cell service you will be able to use differential gps on the phone.

The cell TOWERS - not the phones - depend on very precise timing currently acquired from GPS to permit frequency sharing needed for Time Division Multiple Access (TDMA). Without that timing, they begin to "contention" for time slots (like two people trying to transmit at the same time on the same frequency).

Obviously, cell phones don't depend on GPS because they otherwise wouldn't work indoors. But without the cell towers synchronizing their use of the spectrum, all you've got in your hand is an expensive paper weight.

Here's a good article on how dependent we've become on GPS: https://qz.com/1106064/the-entire-gl...ble-to-attack/. There's a lot more than convenient navigation at stake.

Someone asked me offline if I'm a doomsday worrier. I've worked in cyber security for 20 years. I see complex and sophisticated attacks happening every day. If someone can gain from it, it's inevitable. I'm grateful for everything that DOES work. When I switch on the lights in the morning, I say a little "thank you" to all the good people who did their jobs and repelled the previous night's attacks and who kept the house-of-cards that is our often-naïve technologies standing. Since cyber is a battleground that favors the aggressor, sometimes the attacks still get though.