Impact of sensor tilt on bio-inspired polarized skylight orientation determination

Inspired by many insects, several polarized skylight orientation determination approaches have been proposed. However, almost all of these approaches always require polarization sensors pointing to the zenith of the sky dome. Therefore, the influence of sensor tilts (not pointing to the sky zenith) on bio-inspired polarization orientation determination needs to be analyzed urgently. Aiming at solving this problem, a polarization compass simulation system is designed based on a solar position model, the Rayleigh sky model, and a hypothetical polarization imager. Then, the error characteristics of four typical orientation determination approaches are investigated in detail under the pitch tilt condition, roll tilt condition, and both pitch and roll tilt conditions. Finally, simulations and field experiments indicate that the orientation errors of the four typical approaches are highly consistent when they are subjected to tilt interference; the errors are affected by not only the degree of inclination but also the solar altitude angle and the relative position between the Sun and polarization sensor. The results of this study can be used to estimate the orientation determination error caused by sensor tilts and correct this type of error.