Chong Shen

A combined GPS UWB and MARG locationing algorithm for indoor and outdoor mixed scenario

An indoor or outdoor positioning system is hard to position in cross-region and complex environment. In order to make up for the loss of blind zone in scenario change, we proposed a cooperative positioning system based on GPS/UWB/MARG, which can achieve the seamless positioning between buildings in the hybrid scene. In the hybrid scene, using a weighted fusion algorithm to achieve the cooperative positioning of GPS and UWB, and MARG is used to improve the positioning accuracy of GPS. With data optimization and performance analysis of a subsystem, we process GPS/MARG data and UWB data by weighted fusion method. The optimal positioning information in different positioning environments will be output after independent judgment. The results show that, compared with GPS/MARG positioning system, the average positioning accuracy of the cooperative positioning system is improved by 64% in the hybrid scene. In addition, it expands the application scenario of a single positioning system.

Research on the Technology Used to Inspect the Visual Appearance of Tropical Fruit, based on Machine Vision Color Space

Machine vision (computer vision) technology and image processing has been widely used for the automatic classification of fruit—representing an area for future research. In this chapter, we mainly use the method of machine vision to study color characteristics, size contours, and surface textures of fruit surfaces in the hue, saturation, and value (HSV) color space. The chapter goes on to realize the automatic classification of Hainan tropical fruit presenting typical characteristics.

Network Scalability for Ultra-Wideband Real-Time Location Systems Based on vMISO

For time-based location systems, a common time base is important for obtaining the correct position. However, wireless clock synchronization is considerably easier to deploy in certain environments, such as large areas. A single-region positioning network is often restricted to the anchor communication range. Therefore, multiple master anchors form the basis of an extensible location network and provide an effective means of adapting the system to a complex propagation environment. In this article, we consider simultaneous network scalability with the relative clock synchronization and localization. We first establish an extendable UWB location system model through intelligent response across the routing layer and physical layer. Anchors act as master or slave anchors in different cluster areas and advance the clock check packet (CCP) from an initial region to the surrounding area to achieve clock synchronization of the entire network. The intracluster CCP transmission is achieved by broadcasting, and the intercluster CCP transmissions use vMISO and are automatically driven by the broadcast arrival time for better results. Furthermore, the physical-access and clock synchronization algorithms are discussed. Finally, location tests combined with routing simulations are conducted to demonstrate the performance of the proposed scheme.

Tensor-based angle estimation approach for strictly noncircular sources with unknown mutual coupling in bistatic MIMO radar

In the paper, the estimation of joint direction-of-departure (DOD) and direction-of-arrival (DOA) for strictly noncircular targets in multiple-input multiple-output (MIMO) radar with unknown mutual coupling is considered, and a tensor-based angle estimation method is proposed. In the proposed method, making use of the banded symmetric Toeplitz structure of the mutual coupling matrix, the influence of the unknown mutual coupling is removed in the tensor domain. Then, a special enhancement tensor is formulated to capture both the noncircularity and inherent multidimensional structure of strictly noncircular signals. After that, the higher-order singular value decomposition (HOSVD) technology is applied for estimating the tensor-based signal subspace. Finally, the direction-of-departure (DOD) and direction-of-arrival (DOA) estimation is obtained by utilizing the rotational invariance technique. Due to the use of both noncircularity and multidimensional structure of the detected signal, the algorithm in this paper has better angle estimation performance than other subspace-based algorithms. The experiment results verify that the method proposed has better angle estimation performance.

Comparing Digital Phase-Locked Loop and Kalman Filter for Clock Tracking in Ultrawideband Location System

For timing and synchronization system, digital phase-locked loop (DPLL) and Kalman filter all have been widely used as the clock tracking and clock correction schemes for the similar structure and properties. This paper compares the two schemes used for ultrawideband (UWB) location system. The improved Kalman filter is more immune to interference.