GPS recomendations please
May 5th 2015, 2:43 pm
#46
BE Forum Addict
Joined: May 2012
Location: Qc, Canada
Posts: 3,787
Re: GPS recomendations please
LOL indeed, Schnooks 
My sister & I still argue about which of the 1966 & '69 AA road books are better/worse for UK driving/navigation. Leeds & London are particular trouble spots!!! It would help if Dsis could actually read a map, whether hard copy or on a screen 
.
(We solved the Heathrow problem by no one ever, ever, EVER driving there again! Now if only I could sort YUL...)
My sister & I still argue about which of the 1966 & '69 AA road books are better/worse for UK driving/navigation. Leeds & London are particular trouble spots
!!! It would help if Dsis could actually read a map, whether hard copy or on a screen .(We solved the Heathrow problem by no one ever, ever, EVER driving there again! Now if only I could sort YUL...)
May 5th 2015, 8:22 pm
#47
Magnificently Withering
Joined: Jan 2007
Location: Oakville, ON
Posts: 6,891
Re: GPS recomendations please
TomTom launched some interesting updates for their current 'Go' series this week.
TomTom MyDrive new features
Installing the updates later today - looks interesting!
As for the mapping, TomTom owns TeleAtlas and also provide the mapping for iPhones. Garmin uses NavTeq. NavTeq belongs to Nokia company 'HERE', which it looks like they are about to put up for sale.
Between them, TomTom and Nokia provide mapping for every SatNav that's out there. Google is the only other mapping provider, but I don't think anyone else uses it.
All SatNavs use satellite signals from the USA NavStar GPS satellites or the Russian GLONASS satellites.
The US government or the Russians could turn off civilian access to their satellite signals at a time of war, making the entire world rely on maps!
At the same time, the world of land surveying would go back 25 years because just about every piece of survey equipment now uses GPS to obtain co-ordinates!
That is why the EU and various countries are launching satellites such as the European Galileo system.
TomTom MyDrive new features
Installing the updates later today - looks interesting!
As for the mapping, TomTom owns TeleAtlas and also provide the mapping for iPhones. Garmin uses NavTeq. NavTeq belongs to Nokia company 'HERE', which it looks like they are about to put up for sale.
Between them, TomTom and Nokia provide mapping for every SatNav that's out there. Google is the only other mapping provider, but I don't think anyone else uses it.
All SatNavs use satellite signals from the USA NavStar GPS satellites or the Russian GLONASS satellites.
The US government or the Russians could turn off civilian access to their satellite signals at a time of war, making the entire world rely on maps!
At the same time, the world of land surveying would go back 25 years because just about every piece of survey equipment now uses GPS to obtain co-ordinates!
That is why the EU and various countries are launching satellites such as the European Galileo system.
But, as you say, the navigation aids are only as good as the base maps the satellite data links to. TeleAtlas and NavTeq are much of a muchness, really, though Navteq's mapping tends to be rated more highly by users for accuracy.
Modern survey instruments, by the way, don't normally use the "raw" signal at all, except as an aid to acquisition of the satellite constellation. A survey instrument looks at phase shifts and timing markers in the carrier wave of the GPS signal to generate a very precise position, typically with corrections for atmospheric and orbital errors calculated from a local base station. There are various complex filters and error-correction algorithms embedded in the instrument, resulting in real-time position usually available to a couple of millimeters of accuracy for latitude and longitude, and a centimeter or two for elevation. That would make a geo-caching challenge fairly trivial!
/work intruding on BE conversation
.
