Real‐time object detection using power spectral density of ground‐penetrating radar data

2019 ◽  
Vol 26 (6) ◽  
pp. e2354 ◽  
Author(s):  
Abolfazl Saghafi ◽  
Sajad Jazayeri ◽  
Sanaz Esmaeili ◽  
Chris P. Tsokos
Keyword(s):  
Spectral Density ◽  
Object Detection ◽  
Real Time ◽  
Power Spectral Density ◽  
Ground Penetrating Radar ◽  
Radar Data ◽  
Power Spectral ◽  
Ground Penetrating

scholarly journals On the Introduction of Canny Operator in an Advanced Imaging Algorithm for Real-Time Detection of Hyperbolas in Ground-Penetrating Radar Data

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 541 ◽  
Author(s):  
Željko Bugarinović ◽  
Lara Pajewski ◽  
Aleksandar Ristić ◽  
Milan Vrtunski ◽  
Miro Govedarica ◽  
...  
Keyword(s):  
Real Time ◽  
Ground Penetrating Radar ◽  
Urban Areas ◽  
Radar Data ◽  
Detection Algorithm ◽  
Advanced Imaging ◽  
Canny Operator ◽  
Imaging Algorithm ◽  
Canny Edge ◽  
Ground Penetrating

This paper focuses on the use of the Canny edge detector as the first step of an advanced imaging algorithm for automated detection of hyperbolic reflections in ground-penetrating radar (GPR) data. Since the imaging algorithm aims to work in real time; particular attention is paid to its computational efficiency. Various alternative criteria are designed and examined, to fasten the procedure by eliminating unnecessary edge pixels from Canny-processed data, before such data go through the subsequent steps of the detection algorithm. The effectiveness and reliability of the proposed methodology are tested on a wide set of synthetic and experimental radargrams with promising results. The finite-difference time-domain simulator gprMax is used to generate synthetic radargrams for the tests, while the real radargrams come from GPR surveys carried out by the authors in urban areas. The imaging algorithm is implemented in MATLAB.

scholarly journals LEO Onboard Real-Time Orbit Determination Using GPS/BDS Data with an Optimal Stochastic Model

2020 ◽  
Vol 12 (20) ◽  
pp. 3458
Author(s):  
Xuewen Gong ◽  
Jizhang Sang ◽  
Fuhong Wang ◽  
Xingxing Li
Keyword(s):  
Random Walk ◽  
Spectral Density ◽  
Real Time ◽  
Power Spectral Density ◽  
Orbit Determination ◽  
Navigation Satellite ◽  
Dual Frequency ◽  
Broadcast Ephemeris ◽  
Power Spectral ◽  
Ambiguity Parameter

The advancements of Earth observations, remote sensing, communications and navigation augmentation based on low Earth orbit (LEO) platforms present strong requirements for accurate, real-time and autonomous navigation of LEO satellites. Precise onboard real-time orbit determination (RTOD) using the space-borne data of multiple global navigation satellite systems (multi-GNSS) becomes practicable along with the availability of multi-GNSS. We study the onboard RTOD algorithm and experiments by using America’s Global Positioning System (GPS) and China’s regional BeiDou Navigation Satellite System (BDS-2) space-borne data of the FengYun-3C satellite. A new pseudo-ambiguity parameter, which combines the constant phase ambiguity, the orbit and clock offset error of the GPS/BDS broadcast ephemeris in the line-of-sight (LOS), is defined and estimated in order to reduce the negative effect of the LOS error on onboard RTOD. The analyses on the variation of the LOS error in the GPS/BDS broadcast ephemeris indicate that the pseudo-ambiguity parameter could be modeled as a random walk, and the setting of the power spectral density in the random walk model decides whether the pseudo-ambiguity can be estimated reasonably and the LOS error could be reduced or not. For different types of GPS/BDS satellites, the LOS errors show different variation characteristics, so the power spectral density should be set separately and differently. A numerical search approach is presented in this paper to find the optimal setting of the power spectral density for each type of GPS/BDS satellite by a series of tests. Based on the optimal stochastic model, a 3-dimensional (3D) real-time orbit accuracy of 0.7–2.0 m for position and 0.7–1.7 mm/s for velocity could be achieved only with dual-frequency BDS measurements and the broadcast ephemeris, while a notably superior orbit accuracy of 0.3–0.5 m for position and 0.3–0.5 mm/s for velocity is achievable using dual-frequency GPS/BDS measurements, due to the absorption effect of the estimated pseudo-ambiguity on the LOS error of the GPS/BDS broadcast ephemeris. Compared to using GPS-alone data, the GPS/BDS fusion only marginally improves the onboard RTOD orbit accuracy by about 1–3 cm, but the inclusion of BDS satellites increases the number of the tracked GNSS satellites and thus speeds up the convergence of the filter. Furthermore, the GPS/BDS fusion could help suppress the local orbit errors, ensure the orbit accuracy and improve the reliability and availability of the onboard RTOD when fewer GPS satellites are tracked in some anomalous arcs.

A Real-Time Digital Signal Analyzer Correlator Averager Power Spectral Density Analyzer

1982 ◽  
Vol IE-29 (1) ◽  
pp. 73-82 ◽  
Author(s):  
S. Ganesan ◽  
Girija Gopalrathnam ◽  
M. Renukadevi
Keyword(s):  
Spectral Density ◽  
Real Time ◽  
Power Spectral Density ◽  
Digital Signal ◽  
Power Spectral

An optimized reconfigurable power spectral density converter for real-time shrew DDoS attacks detection

2013 ◽  
Vol 39 (2) ◽  
pp. 295-308 ◽  
Author(s):  
Hao Chen ◽  
Thomas Gaska ◽  
Yu Chen ◽  
Douglas H. Summerville
Keyword(s):  
Spectral Density ◽  
Real Time ◽  
Power Spectral Density ◽  
Ddos Attacks ◽  
Power Spectral
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