Golay complementary waveforms can, in theory, yield radar returns of high range resolution with e... more Golay complementary waveforms can, in theory, yield radar returns of high range resolution with essentially zero sidelobes. In practice, when deployed conventionally, while high signal-to-noise ratios can be achieved for static target detection, significant range sidelobes are generated by target returns of nonzero Doppler causing unreliable detection. We consider signal processing techniques using Golay complementary waveforms to improve radar detection performance in scenarios involving multiple nonzero Doppler targets. A signal processing procedure based on an existing, so called, Binomial Design algorithm that alters the transmission order of Golay complementary waveforms and weights the returns is proposed in an attempt to achieve an enhanced illumination performance. The procedure applies one of three proposed waveform transmission ordering algorithms, followed by a pointwise nonlinear processor combining the outputs of the Binomial Design algorithm and one of the ordering alg...
Sonobuoy fields, consisting of a large network of emitter and receiver sonar sensors on buoys, ar... more Sonobuoy fields, consisting of a large network of emitter and receiver sonar sensors on buoys, are increasingly being used for detection and tracking of underwater targets in a defined maritime area. This study presents a Gaussian mixture version of a multitarget–multisensor (MS) Bayesian-type tracker developed specifically for multistatic sonobuoy fields. Its foundation is the optimal Bayesian MS filter for a single target in clutter. The multi target feature is incorporated using the linear-multitarget paradigm, which is a fast and accurate approximation assuming the density of underwater targets is low. Reliable track initiation and false track discrimination for low signal-to-noise ratio targets are achieved using the amplitude feature of reported detections. The developed tracker is capable of processing measurements with different modalities, depending on the transmitted signal waveform. It is integrated and tested within a realistic multistatic sonar emulator developed by DST Group.
Acoustics Speech and Signal Processing 1988 Icassp 88 1988 International Conference on, Mar 1, 2008
Abstract The use of complementary codes as a means of reducing radar range sidelobes is well-know... more Abstract The use of complementary codes as a means of reducing radar range sidelobes is well-known, but lack of resilience to Doppler is often cited as a reason not to deploy them. This work describes techniques for providing Doppler resilience with an emphasis on tailoring Doppler performance to the specific aim of target tracking. The Doppler performance can be varied by suitably changing the order of transmission of multiple sets of complementary waveforms. We have developed a method that improves Doppler ...
ABSTRACT Intolerance to Doppler is a typical rationale for non-implementation of complementary wa... more ABSTRACT Intolerance to Doppler is a typical rationale for non-implementation of complementary waveforms in radar systems. However, it is known that by careful scheduling of the waveforms this problem can effectively be overcome[1]. This paper extends the ideas [2] for significantly improving Doppler performance in specific Doppler ranges by arranging the transmission of multiple copies of the complementary waveforms according to the pattern of first order Reed-Müller codes. Here we illustrate the scheduling of these sequences of complementary waveforms in the context of tracking. We provide both a theoretical analysis of the Doppler response of waveform sequences constructed in this way and for this application, and computer simulations of a scheduling algorithm which deliveries superior performance for the tracking of an accelerating target.
Modern radar systems have considerable flexibility in their modes of operation. In particular, it... more Modern radar systems have considerable flexibility in their modes of operation. In particular, it is possible to modify the waveform on a pulse to pulse basis, and electronically steered phased arrays can quickly point the radar beam in any feasible direction. Such flexibility calls for new methods of scheduling, both of the waveform and the beam direction so as to optimize the radar performance. We consider a radar system capable of rapid beam steering and of waveform switching. The transmit waveform is chosen from a small library. ...
2005 7th International Conference on Information Fusion, 2005
Abstract Target tracking algorithms have to operate in an environment of uncertain measurement or... more Abstract Target tracking algorithms have to operate in an environment of uncertain measurement origin, in the presence of possibly non-detected target measurements as well as clutter measurements from unwanted scatterers. Integral part of expressions for data association probabilities is the estimate of clutter density. A priori knowledge of the clutter density may be derived in the form of the closed expression, whilst in the case of environmentally caused clutter; clutter measurement density has to be estimated using ...
Final Program and Abstracts on Information, Decision and Control, 2002
Abstract A cooperative sensor network is an array of sensors interconnected by a local or wide ar... more Abstract A cooperative sensor network is an array of sensors interconnected by a local or wide area communications network. Data is shared between the sensors and used as input to an estimator to measure a process. In the paper a stochastic sensor scheduling framework is applied to the localisation of multiple emitter targets using a cooperative sensor network in which the information rate between sensor nodes has been constrained. The stochastic sensor scheduling problem is presented and a practical sub-optimal sensor ...
2012 50th Annual Allerton Conference on Communication, Control, and Computing (Allerton), 2012
ABSTRACT In estimation of scenario parameters from sensor data, the Fisher information induces a ... more ABSTRACT In estimation of scenario parameters from sensor data, the Fisher information induces a Riemannian metric on the manifold of parameters. If the collection of sensors is reconfigured, this metric changes. In this way, sensor configurations are identified with Riemannian metrics on the parameter manifold. The collection of all Riemannian metrics on a manifold forms a (weak) Riemannian manifold, and smooth changes in configuration of the sensor suite manifests as a smooth curve in this space. This paper examines the idea of sensor management via navigation along geodesics in a sub-manifold of this space corresponding to physically viable sensor configurations; i.e., curves that optimize an energy integral in the sub-manifold. In addition to development of the theory, computational examples that illustrate sensor configuration trajectories arising from this scheme in small-scale scenarios are presented.
2013 IEEE International Conference on Acoustics, Speech and Signal Processing, 2013
ABSTRACT Tracking of the orientation of a rigid body based on directional measurements is a key i... more ABSTRACT Tracking of the orientation of a rigid body based on directional measurements is a key issue in many applications. Configurations in this sense are precisely representable as elements of the rotation group SO(3), and the issue devolves to one of tracking on this group, for which and algorithm is described here. Its novelty derives from the use of maximum entropy distributions on these groups as models for the priors, and from the approximation algorithms that permit numerical implementation of such a model. These solutions can be written in a recursive form. While the general ideas apply in all dimensions, the focus of this paper is on the important 3-dimensional case. It is impossible to compute the exact solution; instead, obtained here is a highly effective approximation. It is shown that, in contrast with other approaches, the algorithm described here produces outputs which are both very accurate and statistically meaningful.
2014 IEEE Ninth International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP), 2014
ABSTRACT There is growing interest in using low-cost wearable sensors to model limb movement in a... more ABSTRACT There is growing interest in using low-cost wearable sensors to model limb movement in applications such as stroke rehabilitation and physiotherapy. This paper presents an algorithm for the detection and classification of arm motion in time series collected by wearable inertial sensors. High level arm trajectory features are obtained from raw sensor data using a sensor orientation tracking algorithm and an arm model. The features are then used in a clustering-based classifier. In the classifier training stage, features are clustered using the k-means algorithm, and a histogram of “key poses” is generated from the clustering as a template for each class. In the recognition stage, new data are segmented and matched to the templates. Experiments on human subjects show that by using trajectory features in the proposed approach, we can achieve higher accuracy than a range of benchmark non-temporal classifiers.
The 2012 International Joint Conference on Neural Networks (IJCNN), 2012
Abstract This paper investigates the use of an Inertial Measurement Unit (IMU) as a tool for eval... more Abstract This paper investigates the use of an Inertial Measurement Unit (IMU) as a tool for evaluating surgical performance. The IMU device provides measurements of acceleration and rate of rotation readings which are then processed to obtain assessment metrics. The metrics investigated include stroke detection, stroke distance, as well as stroke time duration. The data processing involves expert systems for bias correction and error reduction for the accelerometer and gyroscope signals.
Golay complementary waveforms can, in theory, yield radar returns of high range resolution with e... more Golay complementary waveforms can, in theory, yield radar returns of high range resolution with essentially zero sidelobes. In practice, when deployed conventionally, while high signal-to-noise ratios can be achieved for static target detection, significant range sidelobes are generated by target returns of nonzero Doppler causing unreliable detection. We consider signal processing techniques using Golay complementary waveforms to improve radar detection performance in scenarios involving multiple nonzero Doppler targets. A signal processing procedure based on an existing, so called, Binomial Design algorithm that alters the transmission order of Golay complementary waveforms and weights the returns is proposed in an attempt to achieve an enhanced illumination performance. The procedure applies one of three proposed waveform transmission ordering algorithms, followed by a pointwise nonlinear processor combining the outputs of the Binomial Design algorithm and one of the ordering alg...
Sonobuoy fields, consisting of a large network of emitter and receiver sonar sensors on buoys, ar... more Sonobuoy fields, consisting of a large network of emitter and receiver sonar sensors on buoys, are increasingly being used for detection and tracking of underwater targets in a defined maritime area. This study presents a Gaussian mixture version of a multitarget–multisensor (MS) Bayesian-type tracker developed specifically for multistatic sonobuoy fields. Its foundation is the optimal Bayesian MS filter for a single target in clutter. The multi target feature is incorporated using the linear-multitarget paradigm, which is a fast and accurate approximation assuming the density of underwater targets is low. Reliable track initiation and false track discrimination for low signal-to-noise ratio targets are achieved using the amplitude feature of reported detections. The developed tracker is capable of processing measurements with different modalities, depending on the transmitted signal waveform. It is integrated and tested within a realistic multistatic sonar emulator developed by DST Group.
Acoustics Speech and Signal Processing 1988 Icassp 88 1988 International Conference on, Mar 1, 2008
Abstract The use of complementary codes as a means of reducing radar range sidelobes is well-know... more Abstract The use of complementary codes as a means of reducing radar range sidelobes is well-known, but lack of resilience to Doppler is often cited as a reason not to deploy them. This work describes techniques for providing Doppler resilience with an emphasis on tailoring Doppler performance to the specific aim of target tracking. The Doppler performance can be varied by suitably changing the order of transmission of multiple sets of complementary waveforms. We have developed a method that improves Doppler ...
ABSTRACT Intolerance to Doppler is a typical rationale for non-implementation of complementary wa... more ABSTRACT Intolerance to Doppler is a typical rationale for non-implementation of complementary waveforms in radar systems. However, it is known that by careful scheduling of the waveforms this problem can effectively be overcome[1]. This paper extends the ideas [2] for significantly improving Doppler performance in specific Doppler ranges by arranging the transmission of multiple copies of the complementary waveforms according to the pattern of first order Reed-Müller codes. Here we illustrate the scheduling of these sequences of complementary waveforms in the context of tracking. We provide both a theoretical analysis of the Doppler response of waveform sequences constructed in this way and for this application, and computer simulations of a scheduling algorithm which deliveries superior performance for the tracking of an accelerating target.
Modern radar systems have considerable flexibility in their modes of operation. In particular, it... more Modern radar systems have considerable flexibility in their modes of operation. In particular, it is possible to modify the waveform on a pulse to pulse basis, and electronically steered phased arrays can quickly point the radar beam in any feasible direction. Such flexibility calls for new methods of scheduling, both of the waveform and the beam direction so as to optimize the radar performance. We consider a radar system capable of rapid beam steering and of waveform switching. The transmit waveform is chosen from a small library. ...
2005 7th International Conference on Information Fusion, 2005
Abstract Target tracking algorithms have to operate in an environment of uncertain measurement or... more Abstract Target tracking algorithms have to operate in an environment of uncertain measurement origin, in the presence of possibly non-detected target measurements as well as clutter measurements from unwanted scatterers. Integral part of expressions for data association probabilities is the estimate of clutter density. A priori knowledge of the clutter density may be derived in the form of the closed expression, whilst in the case of environmentally caused clutter; clutter measurement density has to be estimated using ...
Final Program and Abstracts on Information, Decision and Control, 2002
Abstract A cooperative sensor network is an array of sensors interconnected by a local or wide ar... more Abstract A cooperative sensor network is an array of sensors interconnected by a local or wide area communications network. Data is shared between the sensors and used as input to an estimator to measure a process. In the paper a stochastic sensor scheduling framework is applied to the localisation of multiple emitter targets using a cooperative sensor network in which the information rate between sensor nodes has been constrained. The stochastic sensor scheduling problem is presented and a practical sub-optimal sensor ...
2012 50th Annual Allerton Conference on Communication, Control, and Computing (Allerton), 2012
ABSTRACT In estimation of scenario parameters from sensor data, the Fisher information induces a ... more ABSTRACT In estimation of scenario parameters from sensor data, the Fisher information induces a Riemannian metric on the manifold of parameters. If the collection of sensors is reconfigured, this metric changes. In this way, sensor configurations are identified with Riemannian metrics on the parameter manifold. The collection of all Riemannian metrics on a manifold forms a (weak) Riemannian manifold, and smooth changes in configuration of the sensor suite manifests as a smooth curve in this space. This paper examines the idea of sensor management via navigation along geodesics in a sub-manifold of this space corresponding to physically viable sensor configurations; i.e., curves that optimize an energy integral in the sub-manifold. In addition to development of the theory, computational examples that illustrate sensor configuration trajectories arising from this scheme in small-scale scenarios are presented.
2013 IEEE International Conference on Acoustics, Speech and Signal Processing, 2013
ABSTRACT Tracking of the orientation of a rigid body based on directional measurements is a key i... more ABSTRACT Tracking of the orientation of a rigid body based on directional measurements is a key issue in many applications. Configurations in this sense are precisely representable as elements of the rotation group SO(3), and the issue devolves to one of tracking on this group, for which and algorithm is described here. Its novelty derives from the use of maximum entropy distributions on these groups as models for the priors, and from the approximation algorithms that permit numerical implementation of such a model. These solutions can be written in a recursive form. While the general ideas apply in all dimensions, the focus of this paper is on the important 3-dimensional case. It is impossible to compute the exact solution; instead, obtained here is a highly effective approximation. It is shown that, in contrast with other approaches, the algorithm described here produces outputs which are both very accurate and statistically meaningful.
2014 IEEE Ninth International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP), 2014
ABSTRACT There is growing interest in using low-cost wearable sensors to model limb movement in a... more ABSTRACT There is growing interest in using low-cost wearable sensors to model limb movement in applications such as stroke rehabilitation and physiotherapy. This paper presents an algorithm for the detection and classification of arm motion in time series collected by wearable inertial sensors. High level arm trajectory features are obtained from raw sensor data using a sensor orientation tracking algorithm and an arm model. The features are then used in a clustering-based classifier. In the classifier training stage, features are clustered using the k-means algorithm, and a histogram of “key poses” is generated from the clustering as a template for each class. In the recognition stage, new data are segmented and matched to the templates. Experiments on human subjects show that by using trajectory features in the proposed approach, we can achieve higher accuracy than a range of benchmark non-temporal classifiers.
The 2012 International Joint Conference on Neural Networks (IJCNN), 2012
Abstract This paper investigates the use of an Inertial Measurement Unit (IMU) as a tool for eval... more Abstract This paper investigates the use of an Inertial Measurement Unit (IMU) as a tool for evaluating surgical performance. The IMU device provides measurements of acceleration and rate of rotation readings which are then processed to obtain assessment metrics. The metrics investigated include stroke detection, stroke distance, as well as stroke time duration. The data processing involves expert systems for bias correction and error reduction for the accelerometer and gyroscope signals.
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Papers by Sofia Suvorova