Indoor Three-Dimensional Positioning Method Based on CSS

2014 ◽  
Vol 556-562 ◽  
pp. 3281-3286
Author(s):  
Gao Ping Liu ◽  
Jin Yan Zhang ◽  
Ru Xiang Yang

This paper designs a three-dimensional positioning scheme suitable for indoor, adopts Chirp Spread Spectrum (CSS) and the particular Symmetric Double-Sided Two-Way Ranging (SDS-TWR). Combining BMP085 pressure sensor to measure altitude, it can implement three-dimensional positioning of a moving object in indoor. Due to the complex indoor environment would cause multipath effect when Chirp signal being transmitted, this scheme uses Kalman filtering method to filter out mutative coordinate value, thus the positioning error can be controlled within 1 m.

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lin Ma ◽  
He Dong ◽  
Bin Wang

In our society, realizing intelligent positioning in indoor environments is important to build a smart city. Currently, mutual positioning requirements in the unknown indoor environment are growing fast. However, in such environment, we can obtain neither outdoor radio signal nor the indoor images in advance for online positioning. Therefore, how to achieve mutual positioning becomes an interesting problem. In this paper, we propose a vision-based mutual positioning method in an unknown indoor environment. First, two users take images of the unknown indoor environment, use semantic segmentation network to identify the semantic targets contained in the images, and upload the generated semantic sequence to the user shared database in real time. Then, every time two users reupload a semantic sequence due to a change of location, it is necessary to retrieve whether another user has uploaded the same semantic sequence in the shared database. If the retrieval is successful, it means that two users have seen the same scene. Finally, two users select a target from the two user images taken based on the same scene to establish a three-dimensional coordinate system, respectively, calculate their own position coordinates in this coordinate system, and realize mutual positioning through position coordinate sharing. Experiment results show that our proposed method can successfully realize mutual positioning between two users in an unknown indoor environment, while ensuring high positioning accuracy.


Author(s):  
Roman Grishin ◽  
Dmitriy Nesnov

This article describes the creation of a three-dimensional model of the overpressure sensor Metran-43 using the graphic editor COMPASS-v17, as well as photorealistic images in the program Artisan Rendering and created animation disassembly-Assembly of the device, allowing you to see the internal components of the product.


2021 ◽  
Vol 1920 (1) ◽  
pp. 012088
Author(s):  
Wenjiu Zhu ◽  
Jie Hou ◽  
Zhengqiong Liu ◽  
Zhizhong Ding

Author(s):  
Songzuo Liu ◽  
Habib Hussain Zuberi ◽  
Yi Lou ◽  
Muhmmad Bilal Farooq ◽  
Shahabuddin Shaikh ◽  
...  

AbstractLinear chirp spread spectrum technique is widely used in underwater acoustic communication because of their resilience to high multipath and Doppler shift. Linear frequency modulated signal requires a high spreading factor to nearly reach orthogonality between two pairs of signals. On the other hand, nonlinear chirp spread spectrum signals can provide orthogonality at a low spreading factor. As a result, it improves spectral efficiency and is more insensitive to Doppler spread than the linear counterpart. To achieve a higher data rate, we propose two variants (half cycle sine and full cycle sine) of the M-ary nonlinear sine chirp spread spectrum technique based on virtual time-reversal mirror (VTRM). The proposed scheme uses different frequency bands to transmit chirp, and VTRM is used to improve the bit error rate due to high multipath. Its superior Doppler sensitivity makes it suitable for underwater acoustic communication. Furthermore, the proposed method uses a simple, low-power bank of matched filters; thus, it reduces the overall system complexity. Simulations are performed in different underwater acoustic channels to verify the robustness of the proposed scheme.


RSC Advances ◽  
2021 ◽  
Vol 11 (23) ◽  
pp. 13898-13905
Author(s):  
Chuan Cai ◽  
He Gong ◽  
Weiping Li ◽  
Feng Gao ◽  
Qiushi Jiang ◽  
...  

A three-dimensional electrospun carbon nanofiber network was used to measure press strains with high sensitivity.


Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 569
Author(s):  
Jianzhong Chen ◽  
Ke Sun ◽  
Rong Zheng ◽  
Yi Sun ◽  
Heng Yang ◽  
...  

In this study, we developed a radial artery pulse acquisition system based on finger-worn dense pressure sensor arrays to enable three-dimensional pulse signals acquisition. The finger-worn dense pressure-sensor arrays were fabricated by packaging 18 ultra-small MEMS pressure sensors (0.4 mm × 0.4 mm × 0.2 mm each) with a pitch of 0.65 mm on flexible printed circuit boards. Pulse signals are measured and recorded simultaneously when traditional Chinese medicine practitioners wear the arrays on the fingers while palpating the radial pulse. Given that the pitches are much smaller than the diameter of the human radial artery, three-dimensional pulse envelope images can be measured with the system, as can the width and the dynamic width of the pulse signals. Furthermore, the array has an effective span of 11.6 mm—3–5 times the diameter of the radial artery—which enables easy and accurate positioning of the sensor array on the radial artery. This study also outlines proposed methods for measuring the pulse width and dynamic pulse width. The dynamic pulse widths of three volunteers were measured, and the dynamic pulse width measurements were consistent with those obtained by color Doppler ultrasound. The pulse wave velocity can also be measured with the system by measuring the pulse transit time between the pulse signals at the brachial and radial arteries using the finger-worn sensor arrays.


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