Passive Radio-Frequency Identification Tag-Based Indoor Localization in Multi-Stacking Racks for Warehousing

A Novel Ranging and IMU-Based Method for Relative Positioning of Two-MAV Formation in GNSS-Denied Environments

Global Navigation Satellite Systems (GNSS) with weak anti-jamming capability are vulnerable to intentional or unintentional interference, resulting in difficulty providing continuous, reliable, and accurate positioning information in complex environments. Especially in GNSS-denied environments, relying solely on the onboard Inertial Measurement Unit (IMU) of the Micro Aerial Vehicles (MAVs) for positioning is not practical. In this paper, we propose a novel cooperative relative positioning method for MAVs in GNSS-denied scenarios. Specifically, the system model framework is first constructed, and then the Extended Kalman Filter (EKF) algorithm, which is introduced for its ability to handle nonlinear systems, is employed to fuse inter-vehicle ranging and onboard IMU information, achieving joint position estimation of the MAVs. The proposed method mainly addresses the problem of error accumulation in the IMU and exhibits high accuracy and robustness. Additionally, the method is capable of achieving relative positioning without requiring an accurate reference anchor. The system observability conditions are theoretically derived, which means the system positioning accuracy can be guaranteed when the system satisfies the observability conditions. The results further demonstrate the validity of the system observability conditions and investigate the impact of varying ranging errors on the positioning accuracy and stability. The proposed method achieves a positioning accuracy of approximately 0.55 m, which is about 3.89 times higher than that of an existing positioning method.

IoT Sensor Network Using ESPAR Antenna Based on Beam Scanning Method for Direction Finding

Wireless sensor networks (WSNs) systems based on Internet of Things (IoT) have developed rapidly in recent years. However, interference is a major obstacle to relatively long-distance communications in such networks. It is also very complicated and challenging to fix the exact location of tags in the IoT sensor networks. To overcome these problems, in this paper, an electronic steering parasitic array radiator (ESPAR) antenna used as a beamformer to handle the interference and extend the communication range from the sensors or tags is suggested. In addition, an efficient method, namely beam scanning (BS), is proposed to find the directions of tags. The beam scanning method (BSM) can be used for the selective beam switching (SBS) system by designing an ESPAR or array of ESPAR antennas with the help of CST studio. The antennas exhibit higher gain (8.17 dBi, 11.40 dBi) and proper radiation pattern at a particular direction. In addition, the MATLAB simulation findings indicate that the proposed BSM algorithm provides longer communication range, i.e., 25 m. In order to maximize range while avoiding interference, it is necessary to determine the direction and precise orientation of the tag in the WSN communication systems. Consequently, this work could be applied to an IoT sensor network such as an electrocardiogram system by providing better advantages such as higher localization accuracy and longer operating range.

Big Data and AI for Process Innovation in the Industry 4.0 Era

The fourth industrial revolution or what can be referred to as Industry 4 [...]

Investigation of UHF Signal Strength Propagation at Warehouse Management Applications Based on Drones and RFID Technology Utilization

As a part of the supply chain, inventory management includes, among other things, maintaining the storage of stock, controlling the amount of product for sale and order fulfilment. In business terms, inventory management means the right stock, at the right levels, in the right place, at the right time. In the case of large outdoor warehouses, common identification methods are lengthy and inappropriate. One way to determine inventory easily and quickly is to deploy UAV’s (unmanned aerial vehicle) for product identification purposes. In this case, however, there is a problem in determining where the goods are located. A drone moves at higher altitudes, which can lead to a situation where we will not be able to determine the exact location of the goods. This article deals with a method of determining the correct flight level suitable to distinguish the identified items located at least 2 m apart. The evaluation is performed based on an RSSI (received signal strength indicator) value. The experiment proved that even at maximum reading distance of selected passive UHF RFID tags the two objects can be distinguished.

Elliptic-Curve Crypto Processor for RFID Applications

This work presents an Elliptic-curve Point Multiplication (ECP) architecture with a focus on low latency and low area for radio-frequency-identification (RFID) applications over GF(2163). To achieve low latency, we have reduced the clock cycles by using: (i) three-shift buffers in the datapath to load Elliptic-curve parameters as well as an initial point, (ii) the identical size of input/output interfaces in all building blocks of the architecture. The low area is preserved by using the same hardware resources of squaring and multiplication for inversion computation. Finally, an efficient controller is used to control the inferred logic. The proposed ECP architecture is modeled in Verilog and the synthesis results are given on three different 7-series FPGA (Field Programmable Gate Array) devices, i.e., Kintex-7, Artix-7, and Virtex-7. The performance of the architecture is provided with the integration of a schoolbook multiplier (implemented with two different logic styles, i.e., combinational and sequential). On Kintex-7, the combinational implementation style of a schoolbook multiplier results in power-optimized, i.e., 161 μW, values with an expense of (i) hardware resources, i.e., 3561 look-up-tables and 1527 flip-flops, (ii) clock frequency, i.e., 227 MHz, and (iii) latency, i.e., 11.57 μs. On the same Kintex-7 device, the sequential implementation style of a schoolbook multiplier provides, (i) 2.88 μs latency, (ii) 1786 look-up-tables and 1855 flip-flops, (iii) 647 μW power, and (iv) 909 MHz clock frequency. Therefore, the reported area, latency and power results make the proposed ECP architecture well-suited for RFID applications.