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2021 GPS Accuracy Issue Impacting Some Garmin, Suunto, other GPS Devices
- alinspired 6y agoI might have run into this on a few systems, which started reporting first days of new year as 53rd week of 2021, instead of 2020. Most systems behave as expected: $ date +%G.%V --date="03 Jan 2021 00:00:15" 2020.53 $ date +%G.%V --date="04 Jan 2021 00:00:15" 2021.01
- deleted 6y ago[deleted]
- unilynx 6y ago> In talking to another person in the industry dealing with the issue, they noted that technically 2020 had 53 weeks, and this is the 53rd week. As such, the suspect Sony data file issue might actually be tied to that complexity. Wouldn't be surprised On a positive note, this is the first year in a row of 4 where I didn't see CI errors related to the year currently being 2021 but the 'week-year' still being 2020. (Did find one recent test that hardcoded 2020 instead of just taking the current year though, but at least that doesn't take any further investigation)
- deleted 6y ago[deleted]
- grenoire 6y agoHitting up the classic article, https://infiniteundo.com/post/25326999628/falsehoods-programmers-believe-about-time https://infiniteundo.com/post/25326999628/falsehoods-program...
- dingaling 6y agoIf Sony are doing anything other than just relaying the current almanac then they're doing something wrong: https://www.navcen.uscg.gov/?pageName=gpsAlmanacs https://www.navcen.uscg.gov/?pageName=gpsAlmanacs So it's more likely to be something related to the software implementation rather than the data.
- vesinisa 6y agoRelatedly, I had my Android phone set to the en-US locale. I noticed Calendar was showing 2020 had 52 weeks and all week numbers of 2021 were off by one. I changed to en-UK locale and the issue got resolved. Which begs the question: what on Earth week numbering system the en-US locale was using? I am not aware of any US-specific week numbering system, so it would seem logical for the en-US locale to use the ISO system.
- strombofulous 6y agoFirst day of the week in the US is Sunday, first day of the week in the EU is Monday.
- vesinisa 6y agoThat does not explain it. In US weeks more of W53/2020 lies in 2020 than in ISO weeks, but my phone still labels it W1/2021.
- masklinn 6y ago> In US weeks more of W53/2020 lies in 2020 than in ISO weeks Your error is in assuming every week is uniquely identified as a week-year, but that's only true in ISO week numbering. In ISO, every week-year is exclusive and whichever week contains January 4th is the first of the year, so 2020-12-28/2021-01-03 is 2020-W53 and 2021-01-04/2021-01-10 is 2021-W01 But in the US whichever week contains Jan 1st is the first… and whichever week contains December 31st is the last of the previous year. Meaning the same week can be both X-W53 and X+1-W01 (aka the US system has overlapping / partial weeks at both start and end of year). This is exactly the case this year (and most years, really), the week from December 27th (Sunday) to January 2nd (Saturday) contains both January 1st and December 31st, meaning it's both the last week of 2020 and the first week of 2021.
- vesinisa 6y agoRight, I figured something like this had to be in play. But by whom and where is this US week numbering system actually defined? I can see it is probably implemented in Java by java.time.temporal.WeekFields#SUNDAY_START, but there is no reference to any standard that actually defines it in the documentation. Just this (oddly worded) claim: "This week definition is in use in the US and other European countries."
- notacoward 6y ago> the year currently being 2021 but the 'week-year' still being 2020 Strava seems to have a similar problem. When I pull up leaderboard data for a segment I've just done, "this month" and "this year" and "all time" show my result but "this week" doesn't. Checking now for three segments, each "this week" only includes the part of the week that was in December. BTW, for any other Strava users here, be aware that it's also pretty stupid about years in which you go from one age group to another (in my case from 45-54 to 55-64). AFAICT only your annual CR gets considered for leaderboards, and if that's before your birthday then it'll act as though you've never even done that segment in your new age group.
- Risse 6y agoThese GPS bugs are fascinating, just last year my Suunto watch had a bug where the 1.1.2020 started on wrong weekday (Friday, was supposed to be Wednesday) https://twitter.com/suunto/status/1213128281253392387?lang=en https://twitter.com/suunto/status/1213128281253392387?lang=e...
- Rebelgecko 6y agoThere was a fun one on the Galaxy Nexus phone where the time was off by 12 hours starting in March on leap years
- cx4life 6y agoI run (almost) every day around Greenlake in Seattle. I use a Garmin watch to track those runs, and sure enough after the 1st my route appeared to be not so much around the lake as on the lake. Side note, DCRainMaker is an incredible resource, and has dictated every one of my fitness device purchases for the last... 5 years? It's awesome they're so plugged in to the device landscape that they have a root cause for this bug, while not working directly on the fix.
- jhowell 6y ago> Side note, DCRainMaker is an incredible resource... Agreed. His thorough reveivews have allowed me to make technical purchases with confidence. Most recently in a new power meter for my bicycle.
- C19is20 6y agoBased on DCR and GPLama, I got the assioma pm pedals and then did the MTB pedal mod. DCR also (in effect) got me a new wahoo trainer. I also regularly recommend Hambini, Peak Torque and Durianrider (everyone mentioned is a youtuber) as honest brokers in a very shady world.
- Raidion 6y agoHambini can be almost too honest. He's obviously a great engineer and really knows his stuff, but dang he rips people a new one.
- kevin_thibedeau 6y agoDurian is a problematic person. Best to ignore him.
- tomglynch 6y agoCan someone reply to me when a root cause is found :) Thanks
- SftwreEngnr 6y agoYes
- ben_bai 6y agoHuman error: somebody sometimes did something they were not supposed to do. But they didn't know so they've done it anyways.
- swayson 6y agoI recently read an article (sorry, can't find it now), that one of the risks with 5G is that it may adversely impact navigational systems. Wonder if this may be having an impact on GPS as it grows in market share?
- drmpeg 6y agoThat was about radar altimeters, not GPS. That 5G band hasn't been occupied yet, it's still being auctioned (and it's already the largest auction in US history). https://auctiondata.fcc.gov/public/projects/auction107 https://auctiondata.fcc.gov/public/projects/auction107
- redis_mlc 6y agoThere's also a US company suing (for the past 5 years) to use a mobile phone frequency adjacent to an aviation frequency. Not sure if the proposed interference was related to GPS or not.
- mikewarot 6y agoAuctioning off a public resource like this is a bad idea. All it does is effectively tax the eventual public use of the resource that was free to begin with, whilst creating niches for rent seekers in the process.
- new23d 6y agoTomorrow Never Dies So, it can happen.
- rootsudo 6y agoUse an hackRF, yes you can.
- throw0101a 6y agoGPS signals are actually quite weak (though will be boosted with GPS III satellites), and so can be overwhelmed (and jammed): * https://arstechnica.com/information-technology/2013/07/professor-spoofs-80m-superyachts-gps-receiver-on-the-high-seas/ https://arstechnica.com/information-technology/2013/07/profe... The USN has brought back celestial navigation (sextants) as a backup mechanism in recent years: * https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-officers https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-bac... US is examining backup systems for GPS/GNSS, including bringing back (e)LORAN: * https://www.defenseone.com/ideas/2020/12/we-need-backup-gps-actually-we-need-several-them/170391/ https://www.defenseone.com/ideas/2020/12/we-need-backup-gps-... * https://en.wikipedia.org/wiki/Loran-C https://en.wikipedia.org/wiki/Loran-C
- PoachedSausage 6y agoI believe it was a mistake to decommission eLORAN (both US and Europe), for the reasons you mention. Thankfully we still have terrestrial frequency and time standards (although there was talk of shutting down WWV). Now that the UK has been kicked out of Galileo, perhaps the government might think about reinstating eLORAN, it would be a good use for some the Longwave AM broadcast infrastructure that will be surplus in the next 10 years or so.
- throw0101a 6y agoThe UK had a go of it with eLORAN for a while, but no one else (France, Netherlands) seemed to have been interested, and so it was shelved AFAICT: * https://www.trinityhouse.co.uk/notice-to-mariners/27-15-enhanced-loran-discontinued https://www.trinityhouse.co.uk/notice-to-mariners/27-15-enha... * https://www.maritime-executive.com/article/europe-gives-up-on-eloran https://www.maritime-executive.com/article/europe-gives-up-o... South Korea is having a go at it: * http://www.digitaljournal.com/tech-and-science/technology/ships-ditch-gps-for-eloran-navigation-system-because-of-hacking/article/499423 http://www.digitaljournal.com/tech-and-science/technology/sh... A government or three (NATO?) have to decide on a system (eLORAN or other), publish standards, and buy a bunch of equipment (transmit and receivers) to kick start things.
- jaimex2 6y agoDefinitely not a glitch you'd want on missile targeting software.
- phkahler 6y agoI didnt realize GPS devices needed internet access. This trend of everything needing the net is IMHO a bad thing.
- cnorthwood 6y agoI don't think they require it - the data in question allows it to optimise startup otherwise it can take many minutes to successfully acquire enough data to compute your location
- jonluca 6y agoI'm not sure they actually need the internet - I was under the impression this was a precache of where to look for satellites. It'll still find it without them, it just won't happen as fast. Someone more knowledgeable than can correct me though.
- deleted 6y ago[deleted]
- eknkc 6y agoThey don't. Normally, an initial GPS fix takes some time if the device does not know about the precise arrangement of satellites at that time. It can take up to 15 minutes in case there is no almanac data. Most devices use data obtained from internet for faster GPS fixes. They should function properly offline too.
- Too 6y agoPhase 1: No internet cache, developers optimize for faster offline GPS fixes Phase 2: Someone comes up with smart idea to use internet to optimize initial fix. Performance get faster. Phase 3: PM thinks that offline scenario is not worth optimizing for since most users have internet anyway, performance and features degrades. Phase 4: Some developer forget that offline is even a valid scenario, device becomes useless without connection. Phase 5: Company servers broken. Device useless. We've seen this happen to multiple products. We would like to believe that things top at phase 2 but here again i think we reached all the way to 5. Useless might be an overstatement since it still points somewhat in the vicinity but it certainly not working as intended. Do they have some kind of meter showing how good accuracy it has so you know when it's inaccurate or not?
- arpinum 6y agoMore fascinating to me is that Garmin uses Sony for GPS chips. Given their long history and penetration in marine and aviation, I’m surprised they can’t or don’t want to compete with Sony. Sad if this means Garmin is on the decline.
- imglorp 6y agoMore likely they use Sony for cheap consumer items. Garmin also makes high accuracy survey and aviation products which I'd bet are custom.
- mthoms 6y agoI think they only use the Sony chips in their watch line up. Hopefully someone else can confirm.
- stevehawk 6y agoThey wouldn't be used in their aviation devices, its a different type of GPS https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System
- jcrawfordor 6y agoA surprising number of consumer GPS receivers use WAAS - it's pretty inexpensive to add since the WAAS corrections are downlinked as part of a GPS datastream you need to decode anyway for ephemeris.
- maxerickson 6y agoThe description in the article makes it sound like Sony came out with a much better low power chip. I'm not sure how big a factor battery size is for these watches, but they might not have had much choice. I have a Garmin 645 Music and wouldn't get anything bigger to replace it.
- nradov 6y agoGarmin hasn't designed their own wearable devices GPS (GNSS) chips for many years. They used MediaTek chips since about 2010. Then a couple years ago they switched to Sony for better battery life.
- matsemann 6y agoAs someone that logs to Strava everyday, I've seen a lot of weird maps the last days. Not seen anything weird on my FR945 (as the author), but many of those I follow have noted it in their descriptions of their skiing trips. Their out and back tracks are the same but like offset 100 meters.
- zackify 6y agoI went for a run yesterday and the first half of a 5 miler was completely offset by a few hundred meters. So interesting to find out the cause!