Experimental demonstration of indoor 3D optical wireless positioning and azimuth estimation using steerable line lasers

We present an indoor three-dimensional (3D) optical wireless positioning and azimuth estimation (OWPAE) scheme that utilizes steerable line lasers. This approach enables the simultaneous acquisition of precise 3D coordinate and azimuth of a mobile receiver without requiring a priori knowledge of the radiation pattern of the light source and photo-detector (PD) characteristics. Our work begins with an analysis of the feasibility of using line lasers for OWPAE. Subsequently, by leveraging the geometric relationship between two line lasers and a pair of PDs, we establish the OWPAE model, considering receiver tilt, and design the frame structure for conveying essential information. To evaluate the effectiveness of our proposed OWPAE scheme, we set up an experimental platform. Experimental results confirm that when the receiver is oriented upwards, the system accurately determines the receiver's location with a mean 3D positioning error of 6.3 cm and its azimuth with a mean azimuthal error of 2.8°. When the receiver tilts at a polar angle of 30°, the system remains effective, yielding a mean 3D positioning error of 8.3 cm and a mean azimuthal error of 5.6°.