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For a drone to be affected by GPS speed limits it would have to be a hypersonic drone.
I am curious what timing precision they are achieving. You can easily get ~10 ns with cheapish GNSS modules.
> Well, how about deliberate dilution of precision or intentionally limiting the speed the GPS chip can be used at? Is that a legal requirement or just done on request? I sort of chuckle whenever I hear of limitations like that being put in place as if someone that can construct an ICBM is going to be constrained by the GPS module.
The speed limit in the US is 1000mph, else it’s a munition. I believe the US used to make their GPS slightly inaccurate, but this was done on the satellite side.
> Well, how about deliberate dilution of precision or intentionally limiting the speed the GPS chip can be used at? Is that a legal requirement or just done on request? I sort of chuckle whenever I hear of limitations like that being put in place as if someone that can construct an ICBM is going to be constrained by the GPS module.
The speed limit in the US is 1000mph, else it’s a munition. I believe the US used to make their GPS slightly inaccurate, but this was done on the satellite side.
GPS is still slightly inaccurate in its publicly available form: there's a second frequency broadcasting an encrypted signal, and with both frequencies you can better account for variations in the ionosphere.
Galileo I believe will shortly be the only system with worldwide coverage and publicly available multiple-frequency broadcast.
I am curious what timing precision they are achieving. You can easily get ~10 ns with cheapish GNSS modules.
10 ns is the quoted accuracy, but it’s not easy to verify that and it is very easy to mess up something at that timescale. If something is cheap, I’d be willing to bet their PPS output is not going to be 10 ns accurate. Most applications won’t tell the difference between 10 us and 10 ns accurate, but when you need it, you’ll know it.
for example in pdf: https://processors.wiki.ti.com/images/f/f1/TI_GPS_PPS_Timing...
Earlier quoted context omitted.
The speed limit in the US is 1000mph, else it’s a munition. I believe the US used to make their GPS slightly inaccurate, but this was done on the satellite side.
I find a bit of humor in imagining NASA rocket launches and atmospheric test vehicles being viewed, in some contexts, as a munition.
After all, you don't really need to have an explosive payload: just dropping a heavy enough missile can be devastating.
I am curious what timing precision they are achieving. You can easily get ~10 ns with cheapish GNSS modules.
10 ns is the quoted accuracy, but it’s not easy to verify that and it is very easy to mess up something at that timescale. If something is cheap, I’d be willing to bet their PPS output is not going to be 10 ns accurate. Most applications won’t tell the difference between 10 us and 10 ns accurate, but when you need it, you’ll know it.
Earlier quoted context omitted.
The speed limit in the US is 1000mph, else it’s a munition. I believe the US used to make their GPS slightly inaccurate, but this was done on the satellite side.
There's a few other restrictions as well as the 1000mph speed limit, as far as I'm aware. GPS is still slightly inaccurate in its publicly available form: there's a second frequency broadcasting an encrypted signal, and with both frequencies you can better account for variations in the ionosphere. Galileo I believe will shortly be the only system with worldwide coverage and publicly available multiple-frequency broad…
Should be pretty exciting when it becomes available. To the extent one can be excited about something that takes 20 years to be delivered.
[1] https://www.gps.gov/systems/gps/modernization/civilsignals/