The military has a tendency to disrupt GPS at sea while submarines are operating in the area. Does your commute pass over any large bodies of water? OR larger than average puddles?
CityCyclingEdinburgh Forum » Questions/Support/Help
Why is GPS accuracy on my Garmin so rubbish in the mornings.
(54 posts)- Started 10 years ago by richardlmpearson
- Latest reply from Kenny
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not a support question
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Posted 10 years ago #
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I hope that's not quite true, as it would mean to find our nuclear deterrent, you could just send out a bunch of drones and see which ones reported a loss of GPS signal :-)
Posted 10 years ago # -
certainly used to be true on the solent.
Assuming that it was public knowledge that the subs were going to be in that area (they would announce it on channel 16) - Blocking GPS accuracy over a few square miles making sure you can't pinpoint a bomb within 300 yards is a rather good idea
Posted 10 years ago # -
Ah, OK. I was thinking about when they're circling around in the artic etc. ready to pop their missiles out!
Posted 10 years ago # -
Is it possible that bicycle-mounted GPS are now so ubiquitous that we have reached peak-Garmin, and there is network capacity issues?
Posted 10 years ago # -
Shouldn't think the satellites are bothered by the number of devices on the ground listening for their signals.
What was that other thing some people were launching new satellites for which was supposed to eventually augment GPS?
Posted 10 years ago # -
Wingpig - there's Galileo (EU) and GLONASS (Russia).
There was an article recently I read that the ground-based LORAN service has been updated by the General Lighthouse Authorities (i.e. Trinity House, Commissioners of Northern Lights and Commissioners of Irish Lights) and rebranded as eLORAN as a backup for GPS failure for inshore maritime navigation.
Posted 10 years ago # -
Yes, the radio piece I heard the other day on the eLORAN service was focussed on South Korea who have a hard time of using GPS due to blocking signals sent by the Noth Koreans.
So maybe it's all North Korea's fault?
Posted 10 years ago # -
GPS 100% Accurate this morning. The aliens must have gone home.
Posted 10 years ago # -
Not for me :( back to the same duffness as last week.
Posted 10 years ago # -
I don't think they circle the Arctic Dave. Don't they sit on the sea bed?
Posted 10 years ago # -
Ran both the Garmin and the Strava app on my phone this morning.
Garmin Edge 800 was locked on really well at home, 19ft accuracy. Up to 77ft accuracy by the zoo, then over 100ft once on the NEPN. That all said, the trace on Strava looks pretty good except when I got to the Hawthornvale, but even then it wasn't too far away.
The phone was actually worse. It went a bit crazy near Craigleith, but performed slightly better when I got to Hawthornvale.
I'm so confused.
Posted 10 years ago # -
Clubmate of mine went to Italy yesterday, according to Strava... (he wishes...)
Posted 10 years ago # -
The day before yesterday, I left without having my Edge500 locked. It was far too long and really I don't want to get up earlier in order to factor the time my edge take to lock on satellites! On my way back it never happens, but arguably the situation is more open with less tall buildings around. I have a (naive) question: why don't car's GPS have the same problem? I understand that as opposed to my Garmin edge 500 the track is "forced" to fit on existing roads, which, I guess, helps a lot, but I never heard of drivers having to wait 5-10 minutes in the morning for their GPS to lock on satellites... Or the track suddenly jumping to the road one block further (which is sometimes the level of inaccuracy I have). It's not as if they are especially a lot more expensive than the bike ones....
Posted 10 years ago # -
Aerial size basically, and the fact that car GPS is effectively 'always on'.
As I understand it, the GPS unit in your car usually shares the same antenna as the radio, which may be built in unobtrusively or it may be a roof mounted model. Either way it's an enormous aerial for picking up the GPS signal, compared with anything portable.
Also, the car maintains power to the GPS electronics even when the ignition is off, so it doesn't have to re-acquire when you get in and drive off.
Posted 10 years ago # -
I see. Thanks!
Posted 10 years ago # -
Ok, so I'm now starting to realise that the issues I was having for a few weeks were merely a minor escalation of what was happening before. The only reason I was aware that the GPS was having issues in the morning was because it was completely losing connection to the satellites, and thus no plotting was possible. The past few days, it has not done this, and I've been focusing instead on the accuracy reading on the device. But just now, I've had a look back at my traces in the mornings before the issues started, and I can see that they were similarly "off" at around the same points as they are now. It was just that I wasn't seeing this lack of accuracy, because it's still pretty accurate.
Therefore, the important thing is that I have not lost connection to the satellites for a few days now, so things have indeed returned "to normal". I have, of course, jinxed it by saying this.
Posted 10 years ago # -
Mine has been far better too. Have you tried all the reset options for the device.
Posted 10 years ago # -
Have you tried all the reset options for the device
No, I have not done anything aside from changing it to record every 1 second, rather than the default setting. I only did that so that it wasn't so jumpy when watching Strava flybys.
Posted 10 years ago # -
It may help. Try this:
Hold Lap and Start, Turn on device, release lap and start and then leave for 20 mins (in sight of satelites).
This apparently resets all the satellite data on the device and may correct your inaccuracy.
Posted 10 years ago # -
Ok, done that, let's see what happens tomorrow...
Posted 10 years ago # -
No difference, tbh. Accuracy pretty much the same, as is the plotted line on GC/Endo/Strava. However, once again it didn't lose connectivity, and it mainly struggles when on the NEPN where you'd expect it to be a bit pants anyway.
Posted 10 years ago #
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