This paper aims to develop a novel attitude determination system aided by polarization sensor. An improved heading angle function is derived using the perpendicular relationship between directions of E-vector of linearly polarized light and solar vector in the atmospheric polarization distribution model. The Extended Kalman filter (EKF) with quaternion differential equation as a dynamic model is applied to fuse the data from sensors. The covariance functions of filter process and measurement noises are deduced in detail. The indoor and outdoor tests are conducted to verify the validity and feasibility of proposed attitude determination system. The test results showed that polarization sensor is not affected by magnetic field, thus the proposed system can work properly in environments containing the magnetic interference. The results also showed that proposed system has higher measurement accuracy than common attitude determination system and can provide precise parameters for Unmanned Aerial Vehicle (UAV) flight control. The main contribution of this paper is implementation of the EKF for incorporating the self-developed polarization sensor into the conventional attitude determination system. The real-world experiment with the quad-rotor proved that proposed system can work in a magnetic interference environment and provide sufficient accuracy in attitude determination for autonomous navigation of vehicle.

A bio-inspired polarization sensor with lenses for navigation was evaluated in this study. Two new calibration methods are introduced, referred to as “central-symmetry calibration” (with an integrating sphere) and “noncontinuous calibration”. A comparison between the indoor calibration results obtained from different calibration methods shows that the two proposed calibration methods are more effective. The central-symmetry calibration method optimized the nonconstant calibration voltage deviations, caused by the off-axis feature of the integrating sphere, to be constant values which can be calibrated easily. The section algorithm proposed previously showed no experimental advantages until the central-symmetry calibration method was proposed. The outdoor experimental results indicated that the indoor calibration parameters did not perform very well in practice outdoor conditions. To establish the reason, four types of calibration parameters were analyzed using the replacement method. It can be concluded that three types can be easily calibrated or affect the sensor accuracy slightly. However, before the sensor is used outdoors every time, the last type must be replaced with the corresponding outdoor parameter, and the calculation needs a precise rotary table. This parameter, which is mainly affected by the spectrum of incident light, is the main factor determining the sensor accuracy. After calibration, the sensor reaches an indoor accuracy of ±0.009° and a static outdoor accuracy of ±0.05° under clear sky conditions. The dynamic outdoor experiment shows a ±0.5° heading deviation between the polarization sensor and the inertial navigation system with a ±0.06° angular accuracy.

This study investigated short-term outcomes of Lichtenstein hernia repair using self-gripping Parietex ProGrip mesh in Chinese patients with inguinal hernias. Retrospective analysis of patients undergoing Lichtenstein hernia repair using the Parietex ProGrip mesh at a single hospital in China between July 2012 and June 2013. All patients completed the EuroQol-five dimensions (EuroQoL-5D) and short form-36 questionnaires and were followed up at 1 day, 7 days, 1 month. and 6 months, postoperatively. Ninety cases (66 males, 24 females) were studied. Mean ± standard deviation (SD) patient age was 48.7 ± 16.8 (range, 21-87) years. Most hernias were Gilbert's type II (23%) or III (31%). During 6 months of follow-up, none of the patients had recurrent hernia or systemic postoperative complications. The mean ± SD pain visual analog scale score decreased from 32 ± 10.6 at postoperative Day 1 to 0.67 ± 2.5 at 6 months. From postoperative Day 1 to 6 months, there were marked improvements in health and health-related quality of life; mean ± SD visual analog scale EuroQoL score increased from 55.3 ± 8 to 95.2 ± 3 and mean ± SD HR EuroQoL score from 0.31 ± 0.07 to 0.95 ± 0.02. At 6 months, mean scores in all eight dimensions of the short form-36 questionnaires had increased from baseline. The use of self-fixating Parietex ProGrip mesh in open inguinal hernia repair is simple, rapid, effective, and safe, and is associated with low postoperative pain and improved quality life among patients.

Multioriented bilayer nanowire polarizers are integrated with photodetectors using only one-time nanoimprint lithography and metal deposition process. In order to keep the position of peak external quantum efficiency of the photodetector unchanged, the bilayer nanowire polarizer is designed to have the highest transmission at 440 nm. The photodetector is integrated with the polarizer after surface treatment. The performance of the fabricated device is then tested, and three characteristics are realized: light-intensity sensitive, polarization sensitive, and blue-light sensitive. The proposed integration method simplified the fabrication process, and the fabricated device avoids the alignment error which would be produced by using discrete elements. The results demonstrate that the proposed integration process is a promising method for fabricating photodetectors with polarization function.

A simple integration process of single-layer nanowire gratings (SLNGs) for polarization navigation sensor is proposed. The adaptive capacity of the nanoimprint process on uneven substrate is realized using compressed air and the flexible mold. The plasma ashing process is used to simplify the conventional SLNGs fabrication process. Based on the work mentioned above, six SLNGs areas with $1.3mm×1.3mm$ and six different directions are successfully integrated into a polarization sensitive structure applied to a polarization navigation sensor. The measurement result of quantum efficiency shows good sensitivity, and the angle of polarization measurement error is $<±0.1deg$. The experiment result shows that the proposed process is applicable for the integration of large-area single-layer nanometal patterns.