Positioning Accuracy Evaluation of Radio Emission Sources Using Time Difference of Arrival and Angle of Arrival Methods. Part 3. 3D-Simulation

This work completes a series of studies evaluating positioning accuracy of radiation sources using the differential-range and/or goniometric method for the spatial scenario. A complex of models and methods is proposed for estimating the limits of positioning accuracy by the metric of the scattering ellipsoid of the lower Cramer – Rao boundary and circular spherical deviation in 3D. Based on the developed tools, a quantitative and qualitative analysis of positioning scenarios in superdense 5G radio networks was performed. The assessments made it possible to verify the requirements of 3GPP specifications for the accuracy and reliability of geolocation applications and services in the promising 5G ecosystem.

Sphering Mechanism for the Green Ceramic Balls Ground with the Two-Wheels Grinding Technique

The machining of ceramic balls is one of the main difficulties of the manufacture process of ceramic ball bearings. This paper introduces a new grinding technique for green ceramic balls, the twowheels grinding technique. The sphering mechanism for the green ceramic balls ground with the technique was analyzed in theory, and the influencing factors were studied by experiment. The experimental research presents that the spherical deviation of the ground green ceramic balls can be improved to 0.02mm.