The position accuracy based on Decawave Ultra-Wideband (UWB) is affected mainly by three factors: hardware delays, clock drift, and signal power. This article discusses the last two factors. The general approach to clock drift correction uses the phase-locked loop (PLL) integrator, which we show is subject to signal power variations, and therefore, is less suitable for clock drift correction. The general approach to the estimation of signal power correction curves requires additional measurement equipment. This article presents a new method for obtaining the curve without additional hardware and clock drift correction without the PLL integrator. Both correction methods were fused together to improve two-way ranging (TWR).
Current trends in high performance computing show, that the usage of multiprocessor systems on chip are one approach for the requirements of computing intensive applications. The multiprocessor system on chip (MPSoC) approaches often provide a static and homogeneous infrastructure of networked microprocessor on the chip die. A novel idea in this research area is to introduce the dynamic adaptivity of reconfigurable hardware in order to provide a flexible heterogeneous set of processing elements during run-time. This extension of the MPSoC idea by introducing run-time reconfiguration delivers a new degree of freedom for system design as well as for the optimized distribution of computing tasks to the adapted processing cells on the architecture related to the changing application requirements. The "computing in time and space" paradigm and the extension with the new degree of freedom for MPSoCs will be presented with the RAMPSoC approach described in this paper
Precise indoor localization is a major challenge in the field of localization. In this work we investigate multiple error corrections for the ultra-wideband (UWB) technology, in particular the DecaWave DW1000 transceiver. Both the time-of-arrival (TOA) and the time-difference-of-arrival (TDOA) methods are considered. Various clock-drift correction methods for TOA from the literature are reviewed and compared experimentally. The best performing method is extended to TDOA, corrections for the signal power dependence and the hardware delay are added, and two additional enhancements suggested. These are compared to each other and to TOA in positioning experiments. Index Terms-time-of-arrival (TOA), time-difference-of-arrival (TDOA), two-way-ranging (TWR), DecaWave, ultra-wideband (UWB)
The quadratic system provided by the Time of Arrival technique can be solved analytically or by nonlinear least squares minimization. An important problem in quadratic optimization is the possible convergence to a local minimum, instead of the global minimum. This problem does not occur for Global Navigation Satellite Systems (GNSS), due to the known satellite positions. In applications with unknown positions of the reference stations, such as indoor localization with self-calibration, local minima are an important issue. This article presents an approach showing how this risk can be significantly reduced. The
<p><strong>Abstract.</strong> In this paper we present a versatile multi-sensor vehicle which is used in several research projects. The vehicle is equipped with various sensors in order to cover the needs of different research projects in the area of object detection and tracking, mobile mapping and change detection. We show an example for the capabilities of this vehicle by presenting camera- and LiDAR-based pedestrian detection methods. Besides this specific use case, we provide a more general in-depth description of the vehicle’s hard- and software design and its data-processing capabilities. The vehicle can be used as a sensor carrier for mobile mapping, but it also offers hardware and software components to allow for an adaptable onboard processing. This enables the development and testing of methods related to real-time applications or high-level driver assistance functions. The vehicle’s hardware and software layout result from several years of experience, and our lessons learned can help other researchers set up their own experimental platform.</p>
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