scholarly journals A Ray-Tracing Technique to Characterize GPS Multipath in the Frequency Domain

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Naveen S. Gowdayyanadoddi ◽  
James T. Curran ◽  
Ali Broumandan ◽  
Gérard Lachapelle
Keyword(s):  
Frequency Domain ◽  
Ray Tracing ◽  
Multipath Propagation ◽  
Doppler Frequency ◽  
Real Data ◽  
Frequency Difference ◽  
Line Of Sight ◽  
Gps Measurements ◽  
Sources Of Error ◽  
Non Line Of Sight

Multipath propagation is one of the major sources of error in GPS measurements. In this research, a ray-tracing technique is proposed to study the frequency domain characteristics of multipath propagation. The Doppler frequency difference, also known as multipath phase rate and fading frequency, between direct (line-of-sight, LOS) and reflected (non-line-of-sight, NLOS) signals is studied as a function of satellite elevation and azimuth, as well as distance between the reflector and the static receiver. The accuracy of the method is verified with measured Doppler differences from real data collected in a downtown environment. The use of ray-tracing derived predicted Doppler differences in a receiver, as a means of alleviating the multipath induced errors in the measurement, is presented and discussed.

scholarly journals Measurements and Ray Tracing Simulations for Non-Line-of-Sight Millimeter-Wave Channels in a Confined Corridor Environment

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 85066-85081 ◽  
Author(s):  
Guangrong Yue ◽  
Daizhong Yu ◽  
Hao Qiu ◽  
Ke Guan ◽  
Lin Yang ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Millimeter Wave ◽  
Line Of Sight ◽  
Non Line Of Sight

Improving Accuracy of Ray-Tracing Prediction in Non Line-of-Sight (NLOS) Urban Street Cell Environment beyond 6GHz

2017 ◽  
Vol E100.B (4) ◽  
pp. 566-574
Author(s):  
Nobutaka OMAKI ◽  
Tetsuro IMAI ◽  
Koshiro KITAO ◽  
Yukihiko OKUMURA
Keyword(s):  
Ray Tracing ◽  
Line Of Sight ◽  
Urban Street ◽  
Improving Accuracy ◽  
Non Line Of Sight

scholarly journals Assessment of 5G as an ambient signal for outdoor backscattering communications

2021 ◽  
Author(s):  
Ritayan Biswas ◽  
Jukka Lempiäinen
Keyword(s):  
Frequency Domain ◽  
Ray Tracing ◽  
Network Topology ◽  
Implementation Strategies ◽  
Small Cell ◽  
Line Of Sight ◽  
Radio Network ◽  
Rural Highway ◽  
Radar Equation ◽  
Macro Cellular

AbstractThe aim of this article is to evaluate the applicability of 5G technology as a possible ambient signal for backscattering communications (AmBC). This evaluation considers both urban macro-cellular, small cell as well as rural highway environments. The simulations are performed in outdoor areas including analysis about 5G implementation strategies in different scenarios. Essential aspects of 5G radio network topology such as frequency domain (3.5 GHz and 26 GHz) and antenna locations (offering line-of-sight, LOS) are highlighted and turned to applicability scenarios with AmBC. The LOS scenarios are evaluated to determine the widest applicability area of 5G for AmBC. Typical AmBC applications are studied including collection of data from several sensors to receivers. Evaluation of the applicability of 5G was based on propagation related simulations and calculations utilising the ray tracing technique and the radar equation. The results demonstrate that 5G can be used as an ambient signal for backscattering communications for short ranges for typical sensor sizes. It is also observed that the range of communication is heavily dependent on the the size of the sensor.

Time-resolved non-sequential ray-tracing modelling of non-line-of-sight picosecond pulse LIDAR

2016 ◽  
Author(s):  
Adam Sroka ◽  
Susan Chan ◽  
Ryan Warburton ◽  
Genevieve Gariepy ◽  
Robert Henderson ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Picosecond Pulse ◽  
Line Of Sight ◽  
Time Resolved ◽  
Non Line Of Sight

Research on Vessel Positioning System Based on Kalman Filtering

2011 ◽  
Vol 58-60 ◽  
pp. 2428-2433
Author(s):  
Guang Qian Chu ◽  
Yan Cao ◽  
Chao Liang Si
Keyword(s):  
Kalman Filtering ◽  
Measurement Errors ◽  
Multipath Propagation ◽  
Line Of Sight ◽  
Positioning System ◽  
Positioning Accuracy ◽  
Environmental Models ◽  
Signal Characteristics ◽  
Channel Environment ◽  
Non Line Of Sight

In recent years, the typhoon happens frequently. When typhoon suddenly arrives, the only way to rescue the ship which calls for help in time is to locate the position of the ship in the sea quickly and exactly. But in the ocean, due to the non-ideal channel environment, multipath propagation between accident vessels and monitor stations. All these factors will make the detection of error in measurement of signal characteristics, thus affecting the positioning accuracy. In order to improve the location accuracy of accident vessel in the ocean, two kinds of methods are used. One is to search for realistic channel environmental models for the line-of-sight and the non-line-of-sight propagations to study the characteristics of signal measurements error with good robustness of high-precision positioning algorithms.The other is to analyze the main cause of the different kinds of the measurement errors to find their solutions to decrease the errors.

Integrating the Non-Line of Sight Launching System (NLOS-LS) in the United States Navy

2007 ◽  
Author(s):  
Jonathon Emis ◽  
Bryan Huang ◽  
Timothy Jones ◽  
Mei Li ◽  
Don Tumbocon
Keyword(s):  
United States ◽  
United States Navy ◽  
The United States ◽  
Line Of Sight ◽  
Non Line Of Sight

scholarly journals The degeneracy between primordial non-Gaussianity and foregrounds in 21 cm intensity mapping experiments

2020 ◽  
Vol 499 (3) ◽  
pp. 4054-4067
Author(s):  
Steven Cunnington ◽  
Stefano Camera ◽  
Alkistis Pourtsidou
Keyword(s):  
Nuisance Parameter ◽  
Neutral Hydrogen ◽  
Real Data ◽  
Line Of Sight ◽  
Markov Chain Analysis ◽  
Significant Progress ◽  
Intensity Mapping ◽  
Chain Analysis ◽  
Parallel Text ◽  
Foreground Removal

ABSTRACT Potential evidence for primordial non-Gaussianity (PNG) is expected to lie in the largest scales mapped by cosmological surveys. Forthcoming 21 cm intensity mapping experiments will aim to probe these scales by surveying neutral hydrogen (H i) within galaxies. However, foreground signals dominate the 21 cm emission, meaning foreground cleaning is required to recover the cosmological signal. The effect this has is to damp the H i power spectrum on the largest scales, especially along the line of sight. Whilst there is agreement that this contamination is potentially problematic for probing PNG, it is yet to be fully explored and quantified. In this work, we carry out the first forecasts on fNL that incorporate simulated foreground maps that are removed using techniques employed in real data. Using an Monte Carlo Markov Chain analysis on an SKA1-MID-like survey, we demonstrate that foreground cleaned data recovers biased values [$f_{\rm NL}= -102.1_{-7.96}^{+8.39}$ (68 per cent CL)] on our fNL = 0 fiducial input. Introducing a model with fixed parameters for the foreground contamination allows us to recover unbiased results ($f_{\rm NL}= -2.94_{-11.9}^{+11.4}$). However, it is not clear that we will have sufficient understanding of foreground contamination to allow for such rigid models. Treating the main parameter $k_\parallel ^\text{FG}$ in our foreground model as a nuisance parameter and marginalizing over it, still recovers unbiased results but at the expense of larger errors ($f_{\rm NL}= 0.75^{+40.2}_{-44.5}$), which can only be reduced by imposing the Planck 2018 prior. Our results show that significant progress on understanding and controlling foreground removal effects is necessary for studying PNG with H i intensity mapping.

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