Non-line-of-sight propagation measurements at 60GHz for millimeter-waves WPAN

2008 ◽  
Author(s):  
H. Sawada ◽  
K. Yaginuma ◽  
M. Umehira ◽  
K. Sato ◽  
S. Kato ◽  
...  
Keyword(s):  
Millimeter Waves ◽  
Line Of Sight ◽  
Line Of Sight Propagation ◽  
Non Line Of Sight

IMU-Aided Dual-Frequency RFID Based Localization in LOS/NLOS Hybrid Environment

2017 ◽  
Author(s):  
Jie Wu ◽  
MingHua Zhu ◽  
Bo Xiao ◽  
Wei He
Keyword(s):  
Indoor Localization ◽  
Measurement Unit ◽  
Line Of Sight ◽  
Dual Frequency ◽  
Site Survey ◽  
Line Of Sight Propagation ◽  
The Mean ◽  
Position Precision ◽  
Rf Signal ◽  
Non Line Of Sight

The mitigation of NLOS (non-line-of-sight) propagation conditions is one of main challenges in wireless signals based indoor localization. When RFID localization technology is applied in applications, RSS fluctuates frequently due to the shade and multipath effect of RF signal, which could result in localization inaccuracy. In particularly, when tags carriers are walking in LOS (line-of-sight) and NLOS hybrid environment, great attenuation of RSS will happen, which would result in great location deviation. The paper proposes an IMU-assisted (Inertial Measurement Unit) RFID based indoor localization in LOS/NLOS hybrid environment. The proposed method includes three improvements over previous RSS based positioning methods: IMU aided RSS filtering, IMU aided LOS/NLOS distinguishing and IMU aided LOS/NLOS environment switching. Also, CRLB (Cramér-Rao Low Bound) is calculated to prove theoretically that indoor positioning accuracy for proposed method in LOS/NLOS mixed environment is higher than position precision of only use RSS information. Simulation and experiments are conducted to show that proposed method can reduce the mean positioning error to around 3 meters without site survey.

Optical scattering communication under various aerosol types based on a new non-line-of-sight propagation model

Optik ◽  
2018 ◽  
Vol 164 ◽  
pp. 362-370
Author(s):  
Shaohui Li ◽  
Xuejin Sun ◽  
Riwei Zhang ◽  
Chuanliang Zhang ◽  
Yongbo Zhou ◽  
...  
Keyword(s):  
Propagation Model ◽  
Optical Scattering ◽  
Line Of Sight ◽  
Line Of Sight Propagation ◽  
Aerosol Types ◽  
Non Line Of Sight

Accuracy Bounds for Wireless Localization Methods

2009 ◽  
pp. 380-405 ◽  
Author(s):  
Michael L. McGuire ◽  
Konstantinos N. Plataniotis
Keyword(s):  
Lower Bound ◽  
Location Estimation ◽  
Line Of Sight ◽  
Regularity Conditions ◽  
Node Localization ◽  
Localization Accuracy ◽  
Sensory Data ◽  
Line Of Sight Propagation ◽  
Cramer Rao Lower Bound ◽  
Non Line Of Sight

Node localization is an important issue for wireless sensor networks to provide context for collected sensory data. Sensor network designers need to determine if the desired level of localization accuracy is achievable from their network configuration and available measurements. The Cramér-Rao lower bound is used extensively for this purpose. This bound is loose since it uses only information from measurements in its calculations. Information, such as that from the sensor selection process, is not considered. In addition, non-line-of-sight radio propagation causes the regularity conditions of the Cramér-Rao lower bound to be violated. This chapter demonstrates the Weinstein-Weiss and extended Ziv-Zakai lower bounds for localization error which remain valid with non-line-of-sight propagation. These bounds also use all available information for bound calculations. It is demonstrated that these bounds are tight to actual estimator performance and may be used determine the available accuracy of location estimation from survey data collected in the network area.

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