Prediction on operating range of passive troposcatter detection system

2018 ◽  
Vol 11 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Zan Liu ◽  
Xihong Chen
Keyword(s):  
Electromagnetic Wave ◽  
Analytical Study ◽  
Detection System ◽  
Rain Attenuation ◽  
Propagation Loss ◽  
Line Of Sight ◽  
Time Model ◽  
Operating Range ◽  
Statistic Model ◽  
Loss Models

AbstractElectromagnetic wave of enemy radar propagated by troposcatter is a valuable candidate for beyond line-of-sight detection. There is no analytical study considering the operating range of passive troposcatter detection system. In this paper, we study the way to predict the operating range, which is dominated by propagation loss. The key propagation loss models including statistic model and real-time model are analyzed. During deducing the latter loss model, Hopfield model is introduced to precisely describe the tropospheric refractivity. Meanwhile, rain attenuation is also taken into consideration. Several examples demonstrate the feasibility of predicting operating range through the proposed method.

scholarly journals Passive Visible Light Detection of Humans

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1902 ◽  
Author(s):  
Kenneth Deprez ◽  
Sander Bastiaens ◽  
Luc Martens ◽  
Wout Joseph ◽  
David Plets
Keyword(s):  
Visible Light ◽  
Detection Rate ◽  
Detection System ◽  
Light Emitting Diode ◽  
Line Of Sight ◽  
Controlled Environment ◽  
Ambient Light ◽  
Light Emitting ◽  
Light Sensing ◽  
Reflected Light

This paper experimentally investigates passive human visible light sensing (VLS). A passive VLS system is tested consisting of one light emitting diode (LED) and one photodiode-based receiver, both ceiling-mounted. There is no line of sight between the LED and the receiver, so only reflected light can be considered. The influence of a human is investigated based on the received signal strength (RSS) values of the reflections of ambient light at the photodiode. Depending on the situation, this influence can reach up to ± 50 % . The experimental results show the influence of three various clothing colors, four different walking directions and four different layouts. Based on the obtained results, a human pass-by detection system is proposed and tested. The system achieves a detection rate of 100% in a controlled environment for 21 experiments. For a realistic corridor experiment, the system keeps its detection rate of 100% for 19 experiments.

3A1-R01 Extract Human Factors with Wearable Line-of-Sight Detection System(Wearable Robotics)

2014 ◽  
Vol 2014 (0) ◽  
pp. _3A1-R01_1-_3A1-R01_3
Author(s):  
Miho Ogawa ◽  
Masataka Ozawa ◽  
Kota Sampei ◽  
Carlos Cotes ◽  
Norihisa Miki
Keyword(s):  
Human Factors ◽  
Detection System ◽  
Line Of Sight ◽  
Wearable Robotics

Modeling of Ethylene in Pipeline Leak Detection System

2004 ◽  
Author(s):  
Jakob Bu¨chert
Keyword(s):  
Real Time ◽  
Detection System ◽  
Leak Detection ◽  
Practical Experience ◽  
Time Model ◽  
Pump Stations ◽  
Pipeline Model ◽  
Improve Determination

This paper describes experiences with an improved equation of state (EOS) for ethylene for an existing real time pipeline model. The main scope of the model is leak detection, batch, contaminant and pig tracking. Altogether the pipeline model includes transportation of batched liquid ethylene, ethane, propane, butane and natural gas liquids (NGL). The pipeline is approximately 1900 miles miles long and includes laterals, 33 pump stations, 9 injection/delivery stations and 5 propane terminals. Originally the model used a BWRS EOS for all the above products. At that time a number of false leak alarms were experienced related to pipeline sections containing ethylene. A case study was carried out, specifically for ethylene, to investigate the effect of replacing the BWRS EOS with a modified Helmholtz EOS. The study showed that replacing the EOS on average would improve determination of the ethylene densities by 1.6%–5.6% with an expected reduction in the alarm rate for ethylene cases by approximately 50%. As a result the modified Helmholtz EOS was implemented in the real time model. Results are presented to show the practical experience with the new EOS gained over the last years.

scholarly journals Study on the Detectability of the Sky-Surface Wave Hybrid Radar

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Hou Chengyu ◽  
Ke Guo ◽  
Shi Tiange ◽  
Wang Yuxin
Keyword(s):  
Electromagnetic Wave ◽  
Surface Wave ◽  
High Frequency ◽  
Propagation Loss ◽  
Sea Surface ◽  
Bistatic Radar ◽  
High Frequency Band ◽  
Reflection Point ◽  
Ionospheric Height ◽  
Radar Equation

Working in the HF (high-frequency) band and the transmitter and receiver locating separately, the sky-surface wave hybrid radar both has the capabilities of the OTHR (over-the-horizon radar) and the advantage of the bistatic radar. As the electromagnetic wave will be disturbed by the ionosphere, interfered by the sea clutter and attenuated by the sea surface, the detectability of this radar system is more complex. So, in this paper, we will discuss the problem detailedly. First of all, the radar equation is deduced based on the propagation of the electromagnetic wave. Then, how to calculate the effect of the ionosphere and the propagation loss is discussed. And an example based on the radar equation is given. At last, the ambiguity function is used to analyze the range and velocity resolution. From the result, we find that the resolution has relation with the location of the target and the height of reflection point of the ionosphere. But compared with the location, the effect of the ionospheric height can be ignored.

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