Bonkers GPS

Power lines in the right direction. seem to have an affect

If there are parallel roads, then our garmin often gives the speed limit for the secondary road, e.g. the M1 from Hornsby north, if continually highlights the speed in red and says it is a 60/80km/h zone.

You'd have to check the coverage details during the time.

none of which explains why it only happened on this one day and not the rest of the year.

satellites are pretty reliable hardware, the only temporary outages I'm aware of as sun outages, but GPS should be immune to that.

Could be "regional denial" either some goon with an intentional or unintentional jammer or a legit military exercise.

I have a jammer, tried it on my Navman and it didn't behave that way, only effect appeared to be losing the satellite.

The coverage will be fine, if it can't find satellites it would tell you so.

Perhaps the unit didn't boot properly on that one occasion and screwed it up and upon subsequent reboot was fine.

Gap in coverage by satellite resetting? You've been a victim of gps haking? SBFMTFPT.

Oh what brand? Low battery?

During the drive I reset (little hole in back) three times which had no effect(same behavior before and after)

You wouldn't be the first to be affected by some random GPS issue it seems.

What make/model GPS is it?

Maybe:

Interestingly I just drove home from Auckland and noticed that my normally very accurate and stable GPS was displaying 'jumpy' speed, going up from 98 to 110, back to 102... It'd settle for a while then do similar. I tought it odd. Now reading this I wonder if they're related.

I know a charter boat skipper who said that during the first gulf war the GPS was very unreliable - accurate to within maybe 250m but nowhere near the accurate to ~5m that it was before and after. He said he'd been told the Americans had nerfed the civilian access to the sats by a certain offset to confound the enemy.

Made me wonder if there was war happening somewhere in the world right now - or planned for the near future.

On Sat, 23 Aug 2014 15:16:18 +1000, Chris Jones blathered on in:

Interesting - have to check who's close handy that might have a reason to use a local jammer. I had NFI these devices had managed a foot-hold, so to speak:-)

I doubt they would change the time signals on the sats.

Some GPS's may behave differently, and maybe some jammers work differently in terms of what effect they cause?

I didn't know these were in use by truck drivers and others.

Sadly, they are, for Australia.

The seppos have just passed legislation requiring all phones in the future to have the ability to be shut down remotely... Toby will surely love that :)

Up until May 2000 the yanks used selective availability to reduce the accuracy of GPS for civilian users by putting random offsets on it. They say that they won't do it again but who knows? Military GPS is unaffected by selective availability but you need a military type receiver to decrypt the signal.

Nah, you just do what the surveyors do; either subscribe to a real time offset service or set up your own by having a device at a known gps location calculate the difference between the received and actual signal and pass it on.

It didn't take the surveyors long to figure out that fix. I think the NSW service is back channel on JJJ(?), or it was. no idea if that is still current.

Surveyors use differential GPS which is a whole different thing.

Haven't you had one of these tards walk into you yet? Most them actually seem to expect you to get out of their way, as though I should take into account that they can't see, because they're busy texting or using faecebook on their ishit or phone.