In this paper, bifacial photovoltaic (PV) technologies are evaluated using direct measurements of test coupons for different seasonal solar noon incidence angles. The findings are correlated with theoretical data using ray tracing simulations of both the direct and diffuse component of the incident illumination. Also, a method to characterize the anisotropy of diffuse illumination incident on PV systems is presented. PV systems are designed based on standard conditions in which only direct incidence and isotropic diffuse illumination are considered. The experimental and theoretical findings suggest that anisotropic illumination can cause the PV system output to operate outside of the design specifications. A baffled multi-detector sensor is proposed having a discrete set of azimuthal and declination angle combinations. The sensor constantly samples the irradiance and the incidence angle of the diffuse illumination in all directions. Ray tracing based illumination simulation of dual aperture PV systems and the baffled sensor is presented. The effects on conventional flat plate PV systems are presented and compared to bifacial and holographic planar low concentration (HPC) systems. Including anisotropy in the diffuse illumination component will make PV system performance predictions more accurate. With better predicting capabilities, one can optimize energy harvesting of systems with non-standard mounting conditions and design more effective building integrated PV applications.