The MW810 Mobile Workstation packs an internal "Dead Reckoning" GPS backup feature which continues to estimate your location even when the signal is lost.

ENGADGET: Motorola's rugged ML910 laptop and MW810 mobile workstation

If you study navigation at the Coast Guard or a boating school, you are taught what is called Dead Reckoning or sometimes Ded Reckoning.

FORBES: DEDuced Reckoning is Assembling the Mosaic!

It integrates a multi-GNSS location engine supporting GPS, Galileo, Glonass and Compass satellites to improve the navigation system performance in obstructed environments, Combined with SiRFDRive(R) dead reckoning software, the SiRFprimaII delivers seamless navigation experience whether driving in dense urban canyons or through tunnels or multistory parking lots.

ENGADGET: CSR sharpens indoor and in-car navigation with SiRFstarV, SiRFusion and SiRFprimaII

And with the aid of thrusters and some dead-reckoning, the entry capsule will fly a path through the upper atmosphere.

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