Online ISSN
1751-8792
Print ISSN
1751-8784
IET Radar, Sonar & Navigation
Volume 1, Issue 4, August 2007
Volumes & issues:
Volume 1, Issue 4
August 2007
-
- Author(s): J.M. Muñoz-Ferreras and F. Pérez-Martínez
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 251 –260
- DOI: 10.1049/iet-rsn:20060101
- Type: Article
- + Show details - Hide details
-
p.
251
–260
(10)
Target rotation is the desired motion to obtain descriptive inverse synthetic aperture radar images. However, it can generate blurring effects: the migration through resolution cells. This blurring is more severe when the rotation rate is non-uniform. A method to estimate the non-uniform rotation rate (second-order model) for non-cooperative targets is addressed here. The technique considers the possibility of existence of slant range migration induced by angular motion, unlike other approaches. It needs a previous estimation of the range and radial velocity of two prominent points at two instants and minimises a function in order to estimate the motion parameters, which are used to polar format the radar data. The method is compared with the moving target imaging algorithm of Werness et al. and a time – frequency based technique. Simulated data are used to verify the approach and make the comparisons. - Author(s): X.S. Guo ; Q. Wan ; B. Wu ; W.L. Yang
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 261 –265
- DOI: 10.1049/iet-rsn:20060142
- Type: Article
- + Show details - Hide details
-
p.
261
–265
(5)
A robust and low-complexity parameters estimation method, which combines TLS-ESPRIT and sparse signal representation (SSR) to estimate the parameter of coherently distributed sources is presented. The central direction-of-arrivals are estimated by TLS-ESPRIT based on approximate rotational relationship between two identical uniform linear arrays (ULAs), and angular spreads are given by basis selection method using SSR. Hence the method is a low-complex estimator that does not need a search in one or two-dimensional parameter space. And it owns more robustness in estimating angular spread than one-dimensional distributed source parameter estimator (DSPE). In addition, our method can estimate parameters of the sources with different angular signal distribution functions, which DSPE cannot work. The simulation results prove the effectiveness of our method. - Author(s): V. Myers and M. Pinto
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 266 –273
- DOI: 10.1049/iet-rsn:20060182
- Type: Article
- + Show details - Hide details
-
p.
266
–273
(8)
Modern sidescan sonars provide the ability to image the seafloor with increasingly high resolution. With this comes a corresponding increase in complexity of determining the performance of the sensor, with focus shifting from simple signal detection theory to assess the capability for automatic target recognition (ATR) algorithms to discriminate between different objects based on the shape of the projected acoustic shadows on the seafloor. This paper uses information theory to place bounds on the performance of ATR algorithms which use features based on an object's shadow as a classification cue. Information is used to compute different bounds on the performance of any classification method. The technique is applied to a simple classification task namely to discriminate between circular and square shapes. The effect of sensor characteristics, such as contrast and resolution, are computed. An example is given where the bounds on performance for a sidescan sonar with given characteristics under some environmental conditions are computed. The performance is then analysed as a function of the shapes being classified by changing the circular shape to a superellipse. Although high-frequency imaging sonar is examined here, the method could be applied to other types of monochromatic imagery that contains multiplicative noise. - Author(s): C.X. Li ; M.F. Guo ; X. Pan
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 274 –280
- DOI: 10.1049/iet-rsn:20070009
- Type: Article
- + Show details - Hide details
-
p.
274
–280
(7)
The range of the source can be estimated using the concept of waveguide invariant that describes the interference pattern of sound fields in water. Previous works have been shown that the interference pattern suffers from temporal and spatial variations in uncertain environment. This could cause the performance degradation of the processor. Theoretical analyses are presented for water-depth mismatch and sound-speed profile (SSP) mismatch. The theoretical results are then demonstrated by examples using both simulations and ocean acoustic data. The results suggest that the water-depth mismatch just shifts the peak around the correct one and the sound-speed mismatch can be neglected for the very low frequency even without constant water sound speed. But its robustness to SSP mismatch doesnot exist for higher frequency. For sediment-type mismatch, although a large modelled mistake is introduced, the results are acceptable. This implies that the effect of sediment-type mismatch is minor compared to that of mismatches in water column. On the whole, the processor is robust to environmental mismatch and can be applied to lower frequency with minimal environmental information. - Author(s): J.T. González-Partida ; M. Burgos-García ; B.P. Dorta-Naranjo ; F. Pérez-Martínez
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 281 –288
- DOI: 10.1049/iet-rsn:20060033
- Type: Article
- + Show details - Hide details
-
p.
281
–288
(8)
Frequency modulated continuous wave (FMCW) radars offer many advantages such as low peak power, low probability of interception, low interference to other systems and high range resolution. However, their major drawback is the isolation required between transmitter and receiver that typically leads to the use of two separate antennas for transmission and reception. Some schemes have been proposed to enable FMCW radars to operate with a single antenna. Frequency modulated interrupted continuous wave (FMICW) is a possible solution. However, some considerations must be taken into account before implementing this technique in high resolution radars because of the amount of bandwidth needed. The problems associated with the use of the FMICW technique in broadband radars are analysed and a staggering procedure is proposed to overcome them. This technique is tested using simulated data from a 1 GHz bandwidth millimetre wave sensor, currently under development. The results are compared against other single antenna configurations and the advantages of the staggering technique are shown. - Author(s): T. Thayaparan ; S. Abrol ; E. Riseborough ; L. Stankovic ; D. Lamothe ; G. Duff
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 289 –299
- DOI: 10.1049/iet-rsn:20060103
- Type: Article
- + Show details - Hide details
-
p.
289
–299
(11)
This paper highlights the extraction of micro-Doppler (m-D) features from radar signal returns of helicopter and human targets using the wavelet transform method incorporated with time-frequency analysis. In order for the extraction of m-D features to be realised, the time domain radar signal is decomposed into a set of components that are represented at different wavelet scales. The components are then reconstructed by applying the inverse wavelet transform. After the separation of m-D features from the target's original radar return, time-frequency analysis is then used to estimate the target's motion parameters. The autocorrelation of the time sequence data is also used to measure motion parameters such as the vibration/rotation rate. The findings show that the results have higher precision after the m-D extraction rather than before it, since only the vibrational/rotational components are employed. This proposed method of m-D extraction has been successfully applied to helicopter and human data. - Author(s): M. Vespe ; C.J. Baker ; H.D. Griffiths
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 300 –307
- DOI: 10.1049/iet-rsn:20060049
- Type: Article
- + Show details - Hide details
-
p.
300
–307
(8)
The problem of radar target classification is examined for the case when more than one perspective or viewing angle of the target is available to the sensor. Using full-scale target signature measurements as the source data, it is shown how, for the first time, multiple perspectives enhance the classification performance. Indeed this is the case even if only one additional perspective is available for exploitation. Further, we explore the classification performance both as a function of the number of perspectives and of the signal to noise ratio. Three approaches to high range resolution profile multi-perspective classification have been implemented. This removes any possible bias that could be introduced by a single individual classifier. The results show, for all three, a consistent improvement in the classification performance, as the number of perspectives is increased. The techniques employed also provide considerable insight into the classification process highlighting the degree of complexity of this extremely challenging problem. - Author(s): A. De Maio ; A. Farina ; G. Foglia
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 308 –316
- DOI: 10.1049/iet-rsn:20060113
- Type: Article
- + Show details - Hide details
-
p.
308
–316
(9)
This paper deals with the design and the analysis of constant false alarm rate (CFAR) detectors exploiting knowledge-based (KB) processing techniques. The proposed algorithms are composed of two stages. The former is a KB data selector which, exploiting the a priori information provided by a geographic information system, chooses the training samples for threshold adaptation. The latter stage is a conventional CFAR processor. The performance of the new schemes is analysed in the presence of real radar data, collected by the McMaster IPIX radar, and compared with other common CFAR detectors. The results show that noticeable performance improvements can be obtained suitably exploiting the a priori information available about the sensed environment. - Author(s): P.-L. Shui ; H.-Y. Shang ; Y.-B. Zhao
- Source: IET Radar, Sonar & Navigation, Volume 1, Issue 4, p. 317 –325
- DOI: 10.1049/iet-rsn:20060123
- Type: Article
- + Show details - Hide details
-
p.
317
–325
(9)
In the cases of low signal-to-noise ratios (SNRs), estimating the instantaneous frequency (IF) curves of signals of interest is an interesting topic with many practical applications. Most of the existing methods are based on quadratic time-frequency (TF) distributions, which, however, yield a number of outliers in the cases of low SNRs. In this paper, we construct a new family of TF distributions, namely, the joint distributions, to estimate the IF curves in order to reduce outliers in the cases of low SNRs. The construction of the joint distributions is based on the definition of the directionally smoothed pseudo-Wigner-Ville distributions (DSPWVD) and pointwise adaptive weight averaging of a bank of DSPWVDs with different directions. The segments of the IF curve whose directions are close to that of the DSPWVD can be highlighted by each DSPWVD and the entire IF curve will be enhanced by the joint TF distribution. Simulation results show that the IF estimator based on the joint distributions outperforms that using quadratic TF distributions and the adaptive optimal adaptive kernel distribution in the cases of low SNRs.
Non-uniform rotation rate estimation for ISAR in case of slant range migration induced by angular motion
Parameters localisation of coherently distributed sources based on sparse signal representation
Bounding the performance of sidescan sonar automatic target recognition algorithms using information theory
Effect of environmental mismatch on range estimation using waveguide invariant: theoretical analysis, simulations and experimental results
Stagger procedure to extend the frequency modulated interrupted continuous wave technique to high resolution radars
Analysis of radar micro-Doppler signatures from experimental helicopter and human data
Radar target classification using multiple perspectives
Design and experimental validation of knowledge-based constant false alarm rate detectors
Instantaneous frequency estimation based on directionally smoothed pseudo-Wigner-Ville distribution bank
Most viewed content for this Journal
Article
content/journals/iet-rsn
Journal
5
Most cited content for this Journal
-
Target recognition in synthetic aperture radar images via non-negative matrix factorisation
- Author(s): Zongyong Cui ; Zongjie Cao ; Jianyu Yang ; Jilan Feng ; Hongliang Ren
- Type: Article
-
Overview of frequency diverse array in radar and navigation applications
- Author(s): Wen-Qin Wang
- Type: Article
-
Phase-modulation based dual-function radar-communications
- Author(s): Aboulnasr Hassanien ; Moeness G. Amin ; Yimin D. Zhang ; Fauzia Ahmad
- Type: Article
-
Review of micro-Doppler signatures
- Author(s): Dave Tahmoush
- Type: Article
-
Compressive sensing-based inverse synthetic radar imaging imaging from incomplete data
- Author(s): Sonia Tomei ; Alessio Bacci ; Elisa Giusti ; Marco Martorella ; Fabrizio Berizzi
- Type: Article
