Compact angle diversity receiver concept for visible light positioning

In this work, we investigate a novel angle diversity receiver concept for visible light positioning. The receiver concept, consisting an ultrathin Fresnel lens, embedded in an aperture, mounted on top of a CMOS sensor has been tested and optimized by ray-tracing simulations. This angle-dependent receiver system has the advantage of compact dimensions, a high field-of-view, an off-the-shelf-sensor and relatively high amount of collected light. The origination of the previously calculated Fresnel lens structure is performed by means of grayscale laser lithography. In the presented receiver system, the incoming radiant intensity distribution is converted into an irradiance distribution on the CMOS sensor, where different angles of incidence of incoming light are refracted towards different areas on the CMOS sensor. To verify the optical system experimentally, a prototype of the receiver is placed in a goniometer setup to record images under controlled angles of incidence. Irradiance distributions recorded in the experiment are compared to irradiance distributions obtained by a realistic ray-tracing model. By direct comparison between experiment and simulation, we can verify the optical functionality of the developed optical system of the receiver and investigate the effect of manufacturing imperfections.