Beam-pattern analysis of multi-beam high peak power IR-UWB transmitter tag for indoor positioning and tracking system

Abstract

The precise positioning of an autonomous robot in the wireless sensor network with a high refresh rate is important for well-ordered and efficient systems. An orthogonally transmitted simultaneous multi-beam system improves the geometric dilution of precision (GDOP) and expedites the refresh rate of the system. In this paper, the beam-pattern analysis of an electronically steerable multibeam impulse radio ultra-wideband (IR-UWB) transmitter tag is presented and demonstrated. The multi-beam transmitter tag is optimized to improve the real-time positioning accuracy of an autonomous robot for an indoor positioning and tracking system. Two linear arrays of four elements with an interelement spacing of 18 cm and 10.2 cm are proposed and optimized. The array with spacing 10.2 cm is intentionally configured to produce orthogonal beams, which eventually provides better geometric dilution of precision. The beam steering-angle analysis is performed to better utilize the steering delay range and scanning angle range. The radiation intensity in the direction of the transmitted beam is calculated. Consequently, an intensity table for the Gaussian-modulated multi-cycle IR-UWB beamforming array is proposed. The intensity table gives an easier way to calculate the peak intensity and the number of cycles of the radiated IR-UWB pulse in the transmitted beam direction. The proposed beamforming transmitter arrays are observed to achieve the scanning range from-60° (-90°) to +60° (+90°) with a scanning resolution of 5° and 8° in the measurements.