Enhanced Pedestrian Navigation on Smartphones With VLP-Assisted PDR Integration

Pedestrian dead-reckoning (PDR) is a potential indoor localization technology that utilizes the inertial measurement unit (IMU) to estimate location. However, one of its most significant drawbacks is the accumulation measurement error. This article proposes a PDR system integrated with visible light positioning (VLP) that boasts low accumulated error and can achieve real-time and accurate indoor positioning using both the IMU and the camera sensor on a smartphone. A multiframe fusion method for light-emitting diode (LED)-ID decoding is introduced in the encoding and decoding process of the system, achieving 98.5% decoding accuracy with a 20-bit-long LED-ID at the height of 2.1 m. This method also accommodates the variation in the shutter speeds of cameras and the heights of the LED. Meanwhile, absolute locations and step length could be further calibrated using a single LED, providing an average accuracy within 0.5 m over a 108-m walk.