Bionic Polarization Research Articles

A Bionic Polarization Navigation Sensor Based on Polarizing Beam Splitter

Polarization navigation has been an active research direction in navigation fields due to its autonomy and robustness, especially in global navigation satellite system-denied environment. Most existing bionic polarization sensing schemes employed the linear polarizer as the analyzer. However, the quadrature error between the two sets of mutually orthogonal polarizers is usually inevitable, which may cause the sensor output distortion and directly affect the performance of polarization navigation sensors. In this paper, inspired by the special polarization-sensitive structure of insect compound eyes, a polarizing beam splitter (PBS) based polarization navigation sensor is designed. Concerned with the optical path coupling and extinction ratio inconsistency problem between the transmitted beam and the reflected one of the PBS, the novel sensor model is established, where we introduce a coupling coefficient to solve the problems mentioned above. An algorithm of computing the polarization degree and the polarization azimuth angle is presented based on the model. The unscented Kalman filter calibration method is adopted and the calibration experiments are carried out. Finally, the outdoor static accuracy of the sensor is tested, where the results showed that the sensor designed in this paper achieved high accuracy and good stability for a long time.

A Bionic Polarization Navigation Sensor and Its Calibration Method.

The polarization patterns of skylight which arise due to the scattering of sunlight in the atmosphere can be used by many insects for deriving compass information. Inspired by insects’ polarized light compass, scientists have developed a new kind of navigation method. One of the key techniques in this method is the polarimetric sensor which is used to acquire direction information from skylight. In this paper, a polarization navigation sensor is proposed which imitates the working principles of the polarization vision systems of insects. We introduce the optical design and mathematical model of the sensor. In addition, a calibration method based on variable substitution and non-linear curve fitting is proposed. The results obtained from the outdoor experiments provide support for the feasibility and precision of the sensor. The sensor’s signal processing can be well described using our mathematical model. A relatively high degree of accuracy in polarization measurement can be obtained without any error compensation.

Design and Calibration of a Novel Camera-Based Bio-Inspired Polarization Navigation Sensor

The remarkable ability of animals using the skylight polarization pattern provides a significant inspiration for the autonomous robotic navigation. The bio-inspired polarization navigation approach with advantages of efficiency and reliability has aroused much interesting for experts to perform further research. The sensor of measuring the skylight polarization pattern plays a key role in bio-inspired polarization navigation. A novel camera-based bionic polarization navigation sensor is designed and implemented. We propose a robust measurement method based on the least squares by utilizing all outputs of measurement units. For improving the precision of measurement, the errors of sensor are analyzed, and an effective calibration algorithm is proposed in detail. The experiment results show that the measurement accuracy is improved greatly after calibration. Finally, to evaluate the performance of our sensor, experiments of measuring the actual skylight polarization pattern are performed and compared with the results from the single-scattering Rayleigh theory. The comparison results indicate that our sensor can achieve an effective and accuracy measurement in practice.

A Novel Attitude and Heading Reference Systems Based on Bionic Polarization Sensors

A Novel Attitude and Heading Reference Systems Based on Bionic Polarization Sensors

A Robust Adaptive Angle Algorithm for Imaging Bionic Polarization Navigation Sensor

This paper presents a precise angular algorithm for the imaging bionic polarization navigation sensor. The algorithm is targeted for a imaging sensor with bilayer nanowire polarizer which is multi-orientated of 0°, 60°, 120° and 90°, 150°, 210°. The algorithm is considered to extract intensity values of pixels in homogeneous regions, eliminate noise contained in image and compensate errors occured in the fabricaiton process of nanowire polarization filters. And the occlusion problem has to be compensated by neighboring pixels. The algorithm considered in this paper is able to solve overdetermined system of linear equations, and give a set of least square solutions of the Stokes parameters and the angle of polarization as output. The performance of the algorithm along with the experimental results of the angle measurement are also presented. Based on the comparison results, the algorithm achieves a best performance for the angle of polarization.

The Impact of Typical Aerosol Types on Polarization Sensitive Spectral for Bionic Micro-Nano Polarization Sensor

Based on the OPAC (Optical Properties of Aerosols and Clouds) database, the impact of 8 typical aerosol types on the skylight polarization sensitive is researched. By combining the impact of cloud, the correction between aerosol and the polarization sensitive spectral of insects is analyzed. It can predict the polarization properties of different areas and provide the theoretical basis for the application of bionic micro-nanopolarization sensor.

Positioning algorithm based on skylight polarization navigation

Possessing an autonomous navigation and positioning capabilities that does not rely on GPS or other satellite navigation systems is of great importance when satellite signal is out of service. Many insects, such as desert ant Cataglyphis and dung beetle, are able to derive the direction information according to the pattern of polarization in the sky. Inspired by the polarization sensitivity mechanisms of the insects, several kinds of bionic polarization navigation sensors have been developed. However, all of them can only derive the orientation information, but not the latitude and longitude of the current position. In this study, an integrated positioning algorithm based on skylight polarization navigation was proposed. Combining skylight polarization navigation with celestial navigation, the geographical position could be determined by two independent observations. The result validated the feasibility of the algorithm.