Multipath effects on low-angle tracking at millimetre-wave frequencies

Bruder, J.A.; Saffold, James A.

doi:10.1049/ip-f-2.1991.0023

Cited by 11 publications

(4 citation statements)

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“…Time Reversal techniques are also used to mitigate multipath influence on ISAR imaging in [18]. Multipath also affects tracking performance [19][20][21] and time delay estimation [15]. In that particular case, time delay estimation is a challenging task since the coupling echoes are coherent replicas of the direct returns [22].…”

Section: Introductionmentioning

confidence: 99%

Ship Profile Imaging Using Multipath Backscattering

2019

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This paper addresses the estimation of the height of a point scatterer over a sea surface via multipath exploitation for a High Range Resolution radar that is using pulse range compression, such as Synthetic Aperture Radars. We first focus our attention on the physical model, in particular on the specular/diffuse reflection coefficients, this coefficients being derived from the empirical Miller Brown and Vegh model. The gravity waves are also simulated since they modify the acquisition geometry such as the local grazing angle. Secondly, the signal model is derived, thus allowing an easy derivation of the time delays (direct echo and replicas), these time delays being converted into a height estimation for possible automatic ship recognition applications. Our algorithm is a non-conventional radar signal processing, in other words it uses the backscattered pulse over before range compression and demodulation. The aim of the paper is to understand for which radar and sea parameters, as well as acquisition scenes, it is possible to extract the scatterer height information using the multipath of the backscattered electromagnetic wave.

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Section: Introductionmentioning

confidence: 99%

Ship Profile Imaging Using Multipath Backscattering

2019

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“…If the grazing angle is small and the reflecting surface is smooth, the specular component dominates, which makes the low-angle tracking a complicated problem because of the following reasons: (i) two echoes (the direct and the specular echoes) are basically the same signal except that only the phase and the amplitude of the specular echo are different in fixed amounts from those of the direct echo; that is, they are coherent; (ii) the two echoes lie within the beamwidth, and hence, the angular separation between the two is small [3]; (iii) the two echoes are superpositioned in time, because the two echoes travel almost the same path length, and therefore the range difference between the two echoes are less than the range resolution of the radar [4]. In addition to the specular component, although it may be small, the diffuse component also complicates the low-angle tracking by adding incoherent interference to the received data [5].…”

Section: Introductionmentioning

confidence: 99%

Low-angle tracking of two objects in a three-dimensional beamspace domain

Kim¹,

Yang

Kwak

2012

IET Radar Sonar Navig.

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Among various low-angle tracking methods, the three-dimensional beamspace domain maximum likelihood (3-D BDML) estimation proposed by Zoltowski is a computationally attractive and optimal method that can be processed in the reduced beamspace domain. However, the estimation performance of 3-D BDML deteriorates in the presence of interference or an additional target, especially at low altitudes, because the dimension of the signal and noise exceeds the dimension provided by the three beams. This study proposes a new low-angle tracking method for two objects in a 3-D beamspace domain using a linearly constrained adaptive array. The increased signal dimension owing to the interference or the additional target is reduced in the beamspace domain by using the beamforming weight that is designed to remove the largest principal component in the covariance matrix. Numerical simulation results are provided to show the estimation performance of the proposed method.

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“…Multipath propagation is one of the important reasons of received signal fading. In available literatures, the fading effects caused by multipath propagation do not take weather influences (such as rain, snow and dust storm) into account [e.g., Tong and Akaiwa , 1997; Barger , 1996; Bruder and Saffold , 1990]. The impacts of weather environments on wireless communication system in the literatures focused on attenuation, depolarization, and the contribution of rain‐induced attenuation to noise temperature [e.g., Alouini et al , 1997; Kassianides and Otung , 2003; Fashuyi and Afullo , 2007].…”

Section: Introductionmentioning

confidence: 99%

Rain‐induced effects on the envelope probability density functions in multipath channels

2008

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[1] The fluctuant peculiarities of a signal passing through rain area are studied with the theory of waves propagating through random media. The characteristics of the probability density distribution of a received envelope in rain region are calculated and discussed. The fluctuant rules of a signal in rain region are found. The effects induced by raindrops scattering on the envelope probability density functions (PDFs) in multipath channels are studied using the results in the work by Durgin et al. (2004Durgin et al. ( , 2002. The detailed formulae are derived for one-path channel and two-path channel. The envelope PDFs are calculated for a narrowband signal with a given carrier frequency at the condition of a certain rain rate and a certain propagating distance, which are contrasted with those calculated at unfluctuant condition. The general results of the effects induced by raindrops scattering on the envelope PDFs in multipath channels are found. The methods evaluating the effects on Rayleigh fading distribution model and Rician fading distribution model induced by raindrops scattering are discussed. The general methods for studying the impacts of meteorological scattering environment (snow, dust storm for example) on the envelope PDFs in multipath channels are searched.

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Multipath effects on low-angle tracking at millimetre-wave frequencies

Cited by 11 publications

References 0 publications

Ship Profile Imaging Using Multipath Backscattering

Ship Profile Imaging Using Multipath Backscattering

Low-angle tracking of two objects in a three-dimensional beamspace domain

Rain‐induced effects on the envelope probability density functions in multipath channels

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