Is 1cm accuracy part of Galileo system already operational?
If so, why our phones and other devices cannot utilise it yet?
The July Galileo Outage: What happened and why
21–30 of 63 posts
Re: The July Galileo Outage: What happened and why
#22When was the last time GPS had issues like this? I can imagine that during the early years this happened there as well? Or maybe not, as military quality engineering requirements were stricter.
Or rather silence requirements were stricter. The military is not in the business of publicising failure and weaknesses.
Perhaps in the cold war era.
In the current age, where GPS can be post-processed precisely enough to measure things like land subsidence, there are networks of base stations at fixed locations recording GPS observables and providing historical archives [1] - some operated by US government agencies, some by private companies, some by universities and suchlike.
Due to the use of GPS for things like aircraft navigation, the government also issues 'NANUs' ('Notice Advisory to Navstar Users') and provides an online archive of them [2]. So we can say with some certainty that GPS SATELLITE SVN31 (PRN31) WAS UNUSABLE ON JDAY 349 (15 DEC 97) BEGINNING 1300 ZULU UNTIL JDAY 349 (15 DEC 97) ENDING 2200 ZULU.
Someone who wanted to find the largest recent GPS outage could download the archived NANUs and parse them.
[1] https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/RINEX_... [2] https://navcen.uscg.gov/?Do=gpsArchives&exten=txt
Re: The July Galileo Outage: What happened and why
#23[deleted]
Re: The July Galileo Outage: What happened and why
#24Maybe instead of 24*7 work, some manager thought it was 24/7 work, and sent everyone home.
Re: The July Galileo Outage: What happened and why
#25Is 1cm accuracy part of Galileo system already operational? If so, why our phones and other devices cannot utilise it yet?
Galileo has like a dozen different signals and I believe that most of them aren't broadcasting yet. I'm not sure which of those signals is supposed to give 1cm accuracy, but it could be one of the encrypted signals. Another consideration is that the 1cm accuracy would only be possible with fancy DGPS or RTK setups. 1cm accuracy is doable with GPS today, but unless you're a farmer or land surveyor you probably don't own any hardware capable of realizing that accuracy.
Re: The July Galileo Outage: What happened and why
#26Is 1cm accuracy part of Galileo system already operational? If so, why our phones and other devices cannot utilise it yet?
Galileo has like a dozen different signals and I believe that most of them aren't broadcasting yet. I'm not sure which of those signals is supposed to give 1cm accuracy, but it could be one of the encrypted signals. Another consideration is that the 1cm accuracy would only be possible with fancy DGPS or RTK setups. 1cm accuracy is doable with GPS today, but unless you're a farmer or land surveyor you probably don't o…
I suspect this is an extremely naive question, but why would one signal give a 1cm accuracy and another one not? Shouldn't the satellite just tell you its trajectory + identification info so you can calculate where you are based on that? Or perhaps by signal do you mean the physical electromagnetic properties (frequency etc.) are unsuitable for high accuracy, rather than the actual information content it's supposed to carry?
Re: The July Galileo Outage: What happened and why
#27Earlier quoted context omitted.
Galileo has like a dozen different signals and I believe that most of them aren't broadcasting yet. I'm not sure which of those signals is supposed to give 1cm accuracy, but it could be one of the encrypted signals. Another consideration is that the 1cm accuracy would only be possible with fancy DGPS or RTK setups. 1cm accuracy is doable with GPS today, but unless you're a farmer or land surveyor you probably don't o…
I suspect this is an extremely naive question, but why would one signal give a 1cm accuracy and another one not? Shouldn't the satellite just tell you its trajectory + identification info so you can calculate where you are based on that? Or perhaps by signal do you mean the physical electromagnetic properties (frequency etc.) are unsuitable for high accuracy, rather than the actual information content it's supposed t…
AFAIK each satellite runs two atomic clocks one being much more accurate. Completely different from GPS and way more advanced.
Unsure how it works singal-wise. I assume not only you need different receiver, but also its hardware has to have much higher clock rate.
Re: The July Galileo Outage: What happened and why
#28Earlier quoted context omitted.
I suspect this is an extremely naive question, but why would one signal give a 1cm accuracy and another one not? Shouldn't the satellite just tell you its trajectory + identification info so you can calculate where you are based on that? Or perhaps by signal do you mean the physical electromagnetic properties (frequency etc.) are unsuitable for high accuracy, rather than the actual information content it's supposed t…
AFAIK each satellite runs two atomic clocks one being much more accurate. Completely different from GPS and way more advanced. Unsure how it works singal-wise. I assume not only you need different receiver, but also its hardware has to have much higher clock rate.
Interesting, thanks!
Re: The July Galileo Outage: What happened and why
#29Earlier quoted context omitted.
Or rather silence requirements were stricter. The military is not in the business of publicising failure and weaknesses.
This is a bit of the interesting aspect to this failure. Official channels have overall been pretty weak on details on what all happened in this error. Most public knowledge of what happened has been gleaned from the signals coming off the satellites themselves which anyone can see. This live data combined with understandings of how the system should work is most of the public knowledge of what has been going on. I d…
Exactly. And the galmon network already does that. (It should really be renamed gnssmon at this point, it's far outgrown its Galileo-watching roots.)
You can run a station yourself if you have a Ublox 8- or 9-series receiver.
Re: The July Galileo Outage: What happened and why
#30author here - if anyone has any questions or remarks, let me know!
The operational and management aspects strike me as what happens when you have too many cooks in the kitchen - if everyone is responsible for everything, no one is responsible for anything