Scheduled System Maintenance:
On May 6th, single article purchases and IEEE account management will be unavailable from 8:00 AM - 12:00 PM ET (12:00 - 16:00 UTC). We apologize for the inconvenience.
By Topic

Radar, Sonar and Navigation, IEE Proceedings -

Issue 5 • Date 2 Oct. 2003

Filter Results

Displaying Results 1 - 8 of 8
  • Correction to 'Robust Doppler classification technique based on hidden Markov models'

    Publication Year: 2003
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (157 KB)  

    In the original paper (see ibid., vol.150, no.1, p.33-6, Feb. 2003) a novel technique based on hidden Markov models (HMM) for Doppler classification was presented and performance was reported for a 3-class problem. It was proposed that a HMM model using a cyclic topology would be suited to representing the time varying Doppler signatures observed for moving targets. The paper concluded that the problem was adequately modelled with a HMM algorithm using a cyclic topology with 9 states. At the time of the production of the paper it was believed that the HMMs were using all 9 states to explain the data within each data file that was being classified. However, results obtained subsequent to the publication of the paper show that the models were, for the most part, fitting any given test data file to a single state. The 9 states were being used to explain different data files and thus the system was behaving effectively as a Gaussian mixture based classifier. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Human walking estimation with radar

    Publication Year: 2003 , Page(s): 356 - 365
    Cited by:  Papers (59)  |  Patents (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (895 KB)  

    Radar can be used to observe humans that are obscured by objects such as walls. These humans cannot be visually observed. The radar measurements are used to animate an obscured human in virtual reality. This requires detailed information about the motion. The radar measurements give detailed information about the movements of the human body parts; the Doppler signatures are time-varying and observed in the spectrogram. The authors focus on the extraction of parameters and describe a method for estimating human walking parameters from radar measurements. The parameters are estimated by minimising the difference between a simulated model and real measurements. A human walking model is presented which can be used both to calculate the radar response and visually to animate a walking person. The method is applied to real radar measurements of inbound walking humans from a distance of 20 m. The results show that estimation of the walking parameters is possible. The animated walking human generated with estimated parameters is a realistic likeness of the real walking human. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Generalised wideband ambiguity function of a coherent ultrawideband random noise radar

    Publication Year: 2003 , Page(s): 379 - 386
    Cited by:  Papers (14)  |  Patents (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (515 KB)  

    A coherent ultrawideband (UWB) random noise radar system has been developed and field tested at the University of Nebraska-Lincoln (UNL). A heterodyne correlation technique based on a time-delayed and frequency-shifted replica of the transmit waveform is used to inject coherence within this system. The radar's combined range and range rate resolution characteristics were investigated using the generalised wideband ambiguity function. As in the narrowband random noise waveform case, range and range rate resolutions can be controlled independently, the former being inversely related to the transmit bandwidth, while the latter is inversely related to the bandwidth of the integrating filter. It is also shown that UWB waveforms are not suitable for accurate range rate estimation due to the extended Doppler-spread parameter, i.e. the product of the transmit bandwidth and the target range rate, unless the correlator is matched in the delay rate as well. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Interacting multiple model particle filter

    Publication Year: 2003 , Page(s): 344 - 349
    Cited by:  Papers (41)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (246 KB)  

    A new method for multiple model particle (nonlinear) filtering for Markovian switching systems is presented. This new method is a combination of the interacting multiple model (IMM) filter and a (regularised) particle filter. The mixing and interaction is similar to that in a conventional IMM filter. However, in every mode a regularised particle filter is running. The regularised particle filter probability density is a mixture of Gaussian probability densities. The proposed method is able to deal with nonlinearities and non-Gaussian noise. Furthermore, the new method keeps a fixed number of particles in each mode, and therefore it does not suffer from the potential drawbacks of existing multiple model particle filters for Markovian switching systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Segmentation of SAR images using multitemporal information

    Publication Year: 2003 , Page(s): 367 - 374
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1429 KB)  

    The maximum likelihood method of SAR segmentation has the potential to retain single pixel accuracy without requiring heuristic decisions. Normally, a probabilistic measure is used to merge individual regions without assuming any prior knowledge for the underlying cross-sections. However, for a reasonable multitemporal scene, there may be considerable information available from the varying cross-sections over time. An example is given where this information can be extracted by an initial classification. It is then shown how the segmentation scheme can be modified to incorporate this information via an estimate of the multitemporal underlying class distributions. Using single-look Radarsat data at 8 m resolution, it is demonstrated how the final segment population can be significantly reduced. From a comparison with ground survey data and a high-resolution AirSAR image, the structural quality of the segmentation is shown to be improved. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Early detection of target manoeuvres under a specific false alarm rate

    Publication Year: 2003 , Page(s): 350 - 355
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (254 KB)  

    Two improvements in fading memory average for manoeuvre detection are given. First, according to the characteristics of fading memory average, the exact detection threshold is derived by a Markov chain approach. In conventional algorithms, which ignore the dynamic and dependent properties of fading memory average, only approximate threshold values are computed for a given false alarm rate. Secondly, the univariate fading memory average is further extended to the multivariate form to increase the speed of detection. The multivariate Markov chain approach, which is an extension of the Markov chain approach, can provide exact thresholds for the multivariate fading memory average. Monte Carlo simulation results verify not only the accuracy of the thresholds through both the univariate and multivariate Markov chain approaches, but also the superior detection speed of the proposed multivariate fading memory average. Under the same false alarm rates, the mean time to detection in the multivariate algorithm is 26% less than that in the univariate algorithm. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Asymptotic method for analysis of RCS of arbitrary targets composed by dielectric and/or magnetic materials

    Publication Year: 2003
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (231 KB)  

    A method for the analysis and prediction of monostatic radar cross-section (RCS) of targets of complex geometry is presented. These targets can be formed by multilayer structures of dielectric and magnetic materials. The geometry representation of the targets is given as a collection of NURBS (nonuniform rational B-spline) surfaces. Physical optics (PO) is used to obtain the scattered field of each surface. The PO integral is expressed as a function of the parametric co-ordinates of the surface and is solved using Gordon's (1975) method for planar surfaces and the stationary phase method (SPM) for curved ones. Fresnel coefficients are included in the PO approach to take into account the effect of the RAM material View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multirate interacting multiple model (MRIMM) filtering with out-of-sequence GMTI data

    Publication Year: 2003 , Page(s): 333 - 343
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (346 KB)  

    A multirate approach is developed for incorporating an out-of-sequence (OOS) measurement into a current estimate. There are two major steps in OOS filtering, retrospection from current time to OOS time and updating the current estimate with the OOS measurement, which imposes a high computation and memory burden on implementing OOS filtering. The multirate approach provides an excellent framework for efficient information retrospection and forward updating. A multirate interacting multiple model (MRIMM) filter is developed to track a target with or without manoeuvring behaviour in an environment of out-of-sequence measurement reporting. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

IEE Proceedings Radar, Sonar and Navigation covers the theory and practice of systems involving the processing of signals for radar, radio location, radio navigation and surveillance purposes.

Full Aims & Scope