4 ms·
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
by organsnyder 10y ago
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?
- maxerickson 10y agoWifi 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.
- dogma1138 10y agoThe 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).
- GrumpyYoungMan 10y agoNo, this technique is different. What cell-phones do is rely on pre-mapped databases of wifi and cell tower locations to do trilateration to get a position. The technique the article describes is basically using any stationary RF source as a reference point to tell if your position estimate is drifting. (It's not unlike using a mountain as a landmark for your direction and location while hiking; you don't have to know precisely where the mountain is, you just have to be able to see it and know that it's not moving.) As you point out, it's dependent on what RF sources are nearby (this is the "opportunistic" part of their SOP signal acronym) but can be used to help compensate for the drift that inertial navigation systems have without having to have a pre-compiled database of RF transmitter locations.