> Our approach to improving location accuracy makes a feature out of the very blockage of GNSS signals that causes trouble for standard receivers. How? For Android phones, the LocationManager API provides not just the phone’s position estimate, but also the signal-to-noise ratio (SNR) for each GNSS satellite in view.
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> if the SNR for a satellite is low, then the line-of-sight path is probably blocked or shadowed; if the SNR is high, then the LOS is probably clear. The qualifier “probably” is crucial here: even when the receiver is in a shadowed area, strong reflected signals can still reach it, and even if it is in a clear area, the received signal can be weak (because of destructive interference between LOS and reflected paths, a phenomenon referred to as multipath fading).
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They use something called "probabilistic shadow mapping", which, as drewda mentioned, is work done at UCSB. That team moved over to Uber.
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> if the SNR for a satellite is low, then the line-of-sight path is probably blocked or shadowed; if the SNR is high, then the LOS is probably clear. The qualifier “probably” is crucial here: even when the receiver is in a shadowed area, strong reflected signals can still reach it, and even if it is in a clear area, the received signal can be weak (because of destructive interference between LOS and reflected paths, a phenomenon referred to as multipath fading).
...
They use something called "probabilistic shadow mapping", which, as drewda mentioned, is work done at UCSB. That team moved over to Uber.
Very interesting.