Liam Daniel

Signal characterisation and processing in the forward scatter mode of bistatic passive coherent location systems

The transfer of the forward scatter (FS) concept to passive coherent location (FS PCL) systems provides a new emerging area of research. This article is dedicated to the investigation of various aspects of a bistatic passive coherent location (PCL) system operating in the FS mode. For efficient signal processing, appropriate FS PCL system analysis is presented. It is shown that using a relatively small modernisation of traditional signal processing algorithms, a PCL system may effectively operate against stealth and low profile targets crossing or being located in the vicinity of the radar baseline. The FS signals have been analysed in view of finding key effects and parameters influencing the waveforms and spectra which define the overall signal processing. Experimental results are given to validate the presented analysis.

Maritime UWB forward scattering radar network: Initial study

A scenario for an ultra-wideband (UWB) forward scattering radar (FSR) network for detection of low radar cross section (RCS) maritime surface targets is suggested. A chain of buoys equipped with transceivers which forms a FSR for target detection is considered. In this paper, the first stage of the study is described and major aspects of future work are discussed. It was shown that the high level of surface clutters related to FSR might be reduced by utilisation of UWB technology. As a preliminary further investigation, a numerical simulation of the 3-D RCS for comprehensive models of small maritime targets is obtained and comparisons with simplified target models are made.

Multistatic Forward Scatter Radar for accurate motion parameters estimation of low-observable targets

This paper introduces the MIMO Forward Scatter Radar (FSR) concept to provide an accurate estimation of the motion parameters of a low observable target. In particular, two techniques are introduced to obtain the estimate of the target velocity component normal to the TX-RX baseline, that exploit the multiple transmitters and receivers. Experimental results allow the comparison of the efficiency of the two approaches and demonstrate the potential of MIMO FS configuration.

Ultra-wideband forward scatter radar fence for maritime surveillance — Initial experimental results

The work described in this paper is a continuation of previous analytical work that has progressed to an experimental phase. The paper discusses the development of an ultra-wideband (UWB), forward-scatter radar (FSR) system for the detection and (ultimately) automatic recognition of low reflectivity maritime targets. Here we present the concept, developed hardware and selected initial experimental results. A number of novel ideas have been developed to reduce cost, size, prime power requirement, complexity and utilise the advantages of FSR operation. System benefits include increased target cross section (over conventional bi/monostatic radar), increased target detection capability, robustness to stealth targets, decrease in sea clutter effects from synthesis of extremely narrow beams whilst using omni directional antennas and sub-Hertz Doppler frequency measurement capability. The experimental work investigates the use of an UWB FSR fence for security, UWB propagation measurements, UWB sea clutter measurements at very low grazing angles, UWB spectral coverage and the synthesis of narrow beamwidth antennas using forward scatter pulse transmission.

FSR velocity estimation using spectrogram

This paper focuses on the estimation of target motion parameters in forward scatter radar. A new method based on the use of the Doppler signature spectrogram has been investigated. This allows a rough estimation of target motion parameters even in the presence of significant clutter, when the Doppler signature cannot be used to extract accurate kinematic information. The spectrogram characteristics change depending on targets speed, crossing angle and crossing point, this will be shown in order to explain how it is possible to estimate kinematic information analyzing the spectrogram trend. The performance of this new method is analyzed at the initial stage of the research.

Adaptive calibration in UWB radar

The progress of the late time response (LTR) method applied to the detection and identification of body-worn hidden weapons has been discussed in [1] and [2]. Efficiency of the target signature extraction and its correct interpretation depend on the system subcomponent characteristics as well as the processing algorithms used. Peculiarities in frequency domain (FD) measurements based on a stepped frequency radar technique introduce an ambiguity in the received signal interpretation. In this paper the real time domain (TD) experimentation system and new instant signal calibration procedure are described. Measurements were made in an anechoic chamber to provide complete signal control. Signal processing is based on adaptive filtering algorithms to provide equalization by a reference channel in order to remove any radio frequency (RF) system distortion of the received signal. A generalized matrix pencil-of-function (MPoF) approach is then applied to retrieve the parameters of LTR.

Passive Multifrequency Forward-Scatter Radar Measurements of Airborne Targets Using Broadcasting Signals

This paper demonstrates the feasibility and effectiveness of forward-scatter radar (FSR) target detection based on the signals of opportunity made available by standard radio and TV broadcast transmission stations. This passive FSR (P-FSR) operation is obtained by means of a simple and robust correlation process based on self-mixing. This is shown to be very effective in extracting the characteristic FSR modulation produced by airborne targets, from the signals received from frequency modulated, digital audio broadcasting, and digital video broadcasting transmitters of opportunity. Target detectability is discussed as a function of the carrier frequency, the target size, and its height at the baseline crossing. Experimental results are shown using a wide variety of sources of opportunity, target types, baselines, and receiver configurations. The target signatures obtained from the different illuminators are compared and ways of extracting the kinematic parameters of the aircraft are discussed. This validates the claimed effectiveness and robustness of the P-FSR with the presented processing scheme.

Forward scatter radar mode for passive coherent location systems

The transfer of the forward scatter concept to passive coherent location systems provides an emerging area of research. This paper investigates aspects of such a system through analysis and discussion of previous dedicated forward scatter radar research, showing that indeed the addition of a forward scatter channel to existing passive systems would enhance the current capabilities.

Target Shadow Profile Reconstruction in ground-based forward scatter radar

This paper concerns with the practical aspects of the target profile reconstruction in a single-node ground-based forward scatter radar (FSR) system. Modelling approach for simulation of the target signal return and procedure of the target profile reconstruction are discussed. Experimental set-up and measurements are described. For the first time the reconstructed profiles of three different cars measured in real outdoor environment are demonstrated. The performance of the reconstruction is analysed at this initial stage of the research, operational regimes and conditions to deliver robust and interpretable profile outline are discussed.

Maritime FSR with moving receiver for small target detection

This paper is concerned with the new challenging multi-static and multi-frequency forward scatter radar (FSR) configuration in which one node (transmitter or receiver) is moving. A mathematical model for simulation of the received Doppler signature of the target in such a radar is presented. The experimental set-up and maritime measurements are described and a comparison of the simulated and measured results is given. The performance of the new configuration is analyzed at this initial stage of the research.