NALoc: Nonlinear Ambient-Light-Sensor-based Localization System.

Visible light position (VLP) is a revolutionary technique which enables many promising applications. As the human eye is sensitive to low-rate changes, VLP systems often convey location information through light flickering over 1 KHz, which induces a heavy burden on the VLP receiver. Existing solutions either rely on the high-resolution cameras or a dedicated photodiode to capture the location information, but the high power consumption and extraction deployment cost hinder their wide adoption. In this paper, we present a light-weight VLP system, NALoc, which leverages the ambient light sensor (ALS) readily on many mobile devices to sense high-frequency-modulation location information. To overcome the insufficient sampling ability of ALS, we exploit the nonlinearity of ALS to sense the leaked energy from high frequency(≥ 1 KHz) at a low sampling rate(100 Hz). Extensive evaluations demonstrate that our system can achieve a decimeter-level localization accuracy with about 1 mW power consumption, which is 2000 times less than existing camera-based VLP solutions.