Exploring IMU Attitude and Position Estimation for Improved Location in Indoor Environments

Wearable sensors with an inertial measurement unit (IMU) are popular for indoor positioning and activity pattern detection. The IMUs can be connected to a wireless transmission module, allowing users to monitor and process motion-related parameters remotely. Because of the complexity and uncertainty of signals in indoor environments, a radio frequency (RF) positioning system alone is often insufficient to provide the position accuracy and stability required for many applications, for example, position-guided indoor mobile robots. Our idea is to fuse two or more sources of data to generate highly accurate positioning information. Specifically, we have developed an IMU-aided RF positioning system, aiming to improve the accuracy of the system in indoor environments for mobile robotics. This approach combines the measurements of the accelerometers, gyroscopes, and magnetometer from an IMU via a complementary filter. The work includes a development of a calibration algorithm, which reduces the IMU drift and error. With the calibrated data, the trapezoidal integration method can now better use the accelerometer data to estimate the velocity and displacement of the mobile robot. In order to transform the data in the coordinate system of the IMU mounted on the mobile robot body to the ground positioning coordinate that RF positioning uses, we implement a quaternion rotation algorithm. This enables the fusion of the IMU and RF positioning estimates to accurately determine the moving trajectory of the mobile robot and guide its moving directions

Development of the geodetic coordinate system in Antarctica

Defining a universal geodetic coordinate system is one of the fundamental challenges of geodesy. We present a review of the basic general coordinate systems — the space rectangular coordinate system, the geodetic coordinate system, the topocentric coordinate system, and the plane coordinate system. We then look at the World Geodetic System WGS72 and WGS84 and the International Terrestrial Reference Frames ITRF2000 and ITRF2005, which were introduced when space technology became available. The history of international geodetic coordinate systems in the Antarctic region is briefly reviewed and the development of the geodetic coordinate systems in the Chinese Great Wall Station and Zhongshan Station in Antarctica is outlined. Finally, the issue of coordinate system transformation is discussed

Influence of Gd2O3 and Yb2O3 Co-doping on Phase Stability, Thermo-physical Properties and Sintering of 8YSZ

AbstractThe role of multicomponent rare earth oxides in phase stability, thermo-physical properties and sintering for ZrO2-based thermal barrier coatings (TBCs) materials is investigated. 8YSZ co-doped with 3 mol(Gd2O3 and 3 mol% Yb2O3 (GYb-YSZ) powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed

Progress and prospects in Chinese Antarctic surveying, mapping and remote sensing studies

Antarctic surveying, mapping and remote sensing is one of the important aspects of the Chinese Antarctic geoscience research program that stretch back over 25 years, since the first Chinese National Antarctic Research Expedition (CHINARE) in 1984. During the 1980’s, the geodetic datum, height system and absolute gravity datum were established at the Great Wall and Zhongshan Stations. Significant contributions have been made by the construction of the Chinese Great Wall, Zhongshan and Kunlun Stations in Antarctica. Geodetic control and gravity networks were established in the King George Islands, Grove Mountains and Dome Argus. An area of more than 200 000 km2 has been mapped using satellite image data, aerial photogrammetry and in situ data. Permanent GPS stations and tide gauges have been established at both the Great Wall and Zhongshan Stations. Studies involving plate motion, precise satellite orbit determination, the gravity field, sea level change, and various GPS applications for atmospheric studies have been carried out. Based on remote sensing techniques, studies have been undertaken on ice sheet and glacier movements, the distributions of blue ice and ice crevasses, and ice mass balance. Polar digital and visual mapping techniques have been introduced, and a polar survey space database has been built. The Chinese polar scientific expedition management information system and Chinese PANDA plan display platform were developed, which provides technical support for Chinese polar management. Finally, this paper examines prospects for future Chinese Antarctic surveying, mapping and remote sensing