
No GPS, no problem: Next-generation navigation - sammyjr1
http://robohub.org/no-gps-no-problem-next-generation-navigation/
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AndrewKemendo
Sensor fusion is not new. In fact if you look at what amounts to sensor fusion
in this case, it's still heavily based on satellite timing, not a terrestrial
or celestial reference. RF transmissions don't (generally) come with
directional data embedded so just having those as locus doesn't help, you need
to be able to third reference.

For example you can estimate your location to a cellular BTS based on CRO,
however that only gives you distance not azimuth, it's only if you have three
towers that you get accurate localization - and even then from the signal
alone you don't have a global reference (ie Lat Long or MGRS).

The major overriding issue with geolocation, or localization, is having a
consistent reference. Celestial reference is still the best bar none
reference. GPS is the best DIGITAL reference because of it's simplicity and
accessibility - even though it's accuracy is pretty poor really. Until someone
comes up with a more robust, or more easily digitizable consistent reference,
then everything will be based on satnav.

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falcolas
> Sensor fusion is not new

Nope. In fact, this is the oldest method of radionavigation available. A
beacon of some sort sends a radio signal, and a directional antenna identifies
the bearing to that signal.

Toss in some sort of embedded signal (like, say, a tone-based code which
uniquely identifies a beacon), add another such beacon, and you can fairly
reliably locate yourself in a two dimensional space.

Throw in some form of DME transceiver (it receives a radio pulse and returns
it with a fixed latency between) to give you a distance to that tower, and you
don't even need two of them; just a compass.

I honestly wonder how long until some enterprising soul starts implementing
VOR and DME at a city block level...

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organsnyder
I'm missing the significance of this. Don't many devices (especially cell
phones) already do this with Wifi & cell tower info? Is the innovation here
that there is no GPS receiver used at all? How will that work in rural areas
with less signals to use?

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maxerickson
Wifi and cell towers are used to transmit known positions to the device. This
observes and tracks the positions of the signals in real time and then
determines the changing position of the device from that info.

I skimmed some of the paper, they discuss it in terms of maintaining accuracy
of inertial navigation during loss of GPS signal, not in terms of never using
the GPS signals.

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dogma1138
The cell towers transmitting location data is how assisted GPS already works,
the wifi part is how Google does fused location services on Android (with all
the other sensors).

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dogma1138
What improvements does this offer over the already sensor fused (GPS, Wifi,
Cell, compass, barometer and inertial sensors) location services Android
provides?

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wh0rth
Add this to another reason why traditional GPS "upgrades" for cars are no
longer worthwhile. The other reason being that smartphone navigation works
just as well if not better than most car companies' custom systems.

~~~
ethanbond
It _is_ nice to have if you're an American driving in a different country,
though. Maybe not enough to justify the cost, but very helpful to have.
American phones are basically crippled within 100ft of the Canadian border.

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azaydak
As someone who works, studies, and has published in this area or work, there
is nothing new or novel about what they did. They only repeated work and ideas
that have been around for a while and hyped it up.

