Feasibility of Cosmic Object Detection Using an X-ray FSR System

This paper explores the concept of a Forward Scattering Radar (FSR) system with a rotational transmitter for target detection and localization. Most of the research and development in FSR used a fixed dedicated transmitter; therefore, the detection of stationary and slow moving target is very difficult. By rotating the transmitter, the received signals at the receiver contain extra information carried by the Doppler due to the relative movement of the transmitter-target-receiver. Hence, rotating the transmitter enhances the detection capability especially for a stationary and slow-moving target. In addition, it increases the flexibility of the transmitter to control the signal direction, which broadens the coverage of FSR networks. In this paper, a novel signal processing for the new mode of FSR system based on the signal’s joint time-frequency is proposed and discussed. Additionally, the concept of the FSR system with the rotational transmitter is analyzed experimentally for the detection and localization of a stationary target, at very low speed and a low profile target crossing the FSR baseline. The system acts as a virtual fencing of a remote sensor for area monitoring. The experimental results show that the proposed mode with the new signal processing scheme can detect a human intruder. The potential applications for this system could be used for security and border surveillance, debris detection on an airport runway, ground aerial monitoring, intruder detection, etc.

The forward scatter signature of a target provides the radar systems designer with an alternative approach to the detection of 'very low radar cross section (RCS)' targets. This paper outlines the rationale for a forward scatter radar system, the forward scatter principle, and the architecture of a forward scatter radar systems performance model. This model has been developed to analyse the effect of variations in the choice of operating frequency, transmitter and receiver characteristics, detection and tracking algorithms. The paper discusses these aspects with results from modelling and performance predictions for target forward scatter signature, transmit and receive antenna designs, analogue to digital converter (ADC) performance and coverage for a forward scatter radar system operating in the ultra high frequency (UHF) band.

In this paper we consider a modified sub-optimal signal processing algorithm for marine target detection in a Forward Scatter Radar (FSR) system. The algorithm is based on a matched filtering approach where the filter parameters should be previously estimated. In contrast to the previously developed algorithms, the estimation of target parameters (time, velocity, length) is carried out by means of maximisation of the cross-correlation coefficient between frequencies of the input signal and the reference signal. The algorithm presented in this paper is verified by experimental data, and it can be also applied in some other bistatic radars. (5 pages)

In a forward scatter radar system, the forward scatter shadow ratio to characterize a target is introduced as the ratio of the total received power density to the incident power density for a receiver at a certain location. Numerical simulations show that the forward scatter shadow ratio is related to the size of the target as well as the position of the receiver relative to the target. It is a more suitable parameter for studying target detectability than the radar cross-section.

The focus of this paper is on the detection of moving targets with a Forward Scatter Radar system. More precisely, a non-coherent detection strategy is considered and theoretical closed-form expressions of the probability of false alarm and of the probability of detection are derived in order to allow performance prediction and support system design. Finally the theoretical contribution is verified through simulations.

This paper presents a passive radar system using a signal of opportunity from Digital Video Broadcasting Satellite (DVB-S). The ultimate purpose of the system is to be used as an air traffic monitoring and surveillance system. However, the work focuses on drone detection as a proof of the concept. Detecting a drone by using satellite-based passive radar possess inherent challenges, such as the small radar cross section and low speed. Therefore, this paper proposes a unique method by leveraging the advantage of forward-scattering radar (FSR) topology and characteristics to detect a drone; in other words, the system is known as a passive FSR (p-FSR) system. In the signal-processing algorithm, the empirical mode decomposition (EMD) is applied to the received signal to extract the unique feature vector of the micro-Doppler frequency from the drone’s rotating blades. The paper highlights the p-FSR experimental setup and experiment campaign to detect drones. The experimental results show the feasibility of the p-FSR using a signal transmitted from a satellite to detect flying drone crossing the forward-scatter baseline between the satellite and ground station.

The feasibility of the estimation of a target’s coordinates solely from the Doppler data measured by forward-scatter radar systems (RSs) is analyzed. It is shown that the coordinates’ ambiguity is inherent in a bistatic RS with one transmitting antenna and one receiving antenna. This ambiguity is eliminated in a system with one transmitting antenna and two receiving antennas located close to each other. Algorithms for determining the target’s coordinates in this system are proposed. The accuracy of estimating the target’s coordinates is evaluated and compared to that obtained with a bistatic RS that measures the Doppler frequency and a signal’s direction of arrival.

In this paper we analyze the power budget and calculate signal to noise ratio (SNR) and radar cross section (RCS) for different ground targets using a forward scattering radar (FSR) system, which consists of a transmitter mounted on a satellite of GPS and a receiver located on the Earth's surface. The FSR is a specific bistatic radar system where the bistatic angle is near 180o, and the target is located near the transmitter-receiver baseline. Theoretical and numerical calculations of SNR and RCS are presented for different ground targets when the GPS L1 signal is transmitted by satellites. The SNR and RCS are also estimated by using real records of the GPS signal shadows from different targets. The obtained numerical and experimental results are analyzed and discussed.

Bistatic radars, specifically forward-scatter radars, are proposed as an alternative to standard monostatic radars against targets whose radar cross sections (RCS) have been reduced by passive means. Forward-scatter radars operate by detecting echoes from a targets forward-scatter RCS, which is insensitive to effects of passive RCS reduction techniques. However, the performance of the forward-scatter radar is compromised when the angular separation between the interference, which propagates directly from the transmitter to the receiver, and the target return is less than the Rayleigh resolution limit of the receiving antenna. This research presents the results of a parametric study of the ability of a forward-scatter radar to detect and measure the bearing of a large target, whose RCS is reduced via passive means. Super-resolution array processing techniques, particularly root-MUSIC (multiple signal classification), are used to overcome the traditional limitations resulting from the Rayleigh resolution limit of the antenna. The study compares the received power and the bearing measurement accuracy of the forward-scatter radar to that of an equivalent monostatic radar system. The results indicate that forward-scatter radars enjoy advantages in detection and bearing measurement when the backscatter RCS of the target has been reduced and when the target is close to the baseline. The results also indicate that, through the use of super-resolution array processing the capability of the forward-scatter radar to accurately measure the bearing of the target is dependent upon the amount of interference from the direct wave (i.e., the wave which propagates from the transmitter directly to the receiver) and the correlation between the direct wave and the target echo. Good bearing estimates can be achieved if the correlation coefficient is less than 0.95. Bearing measurements may be improved by suppressing the direct wave by either sidelobe control or null steering techniques. >

This paper introduces a novel MIMO configuration for Forward Scatter Radar (FSR) systems aimed at extending the capabilities of existing SIMO-based amplitude-only processing methods. Building on prior work, we propose a generalization of the FSR architecture to include both multiple transmit and receive antennas. A key challenge-signal separation among transmitters-is addressed through a frequency division multiplexing (FDM) strategy. We develop a two-dimensional array processing framework that enables joint estimation of Direction of Departure (DOD) and Direction of Arrival (DOA) using amplitude-only data. Both ideal and realistic signal separation scenarios are analyzed, and the resulting processing schemes are derived. Simulations demonstrate the feasibility of the approach and its ability to accurately localize and track targets in the angular domain.

Most of the currently established techniques for breast cancer have inherent disadvantages, such as destructive effects, image accuracy, and others. In addition, mammography and nuclear methods have a potential for producing harmful ionization effects in humans. Another technique for breast cancer detection is microwave imaging radar, which has the advantage of a less hazardous modality and is a non-destructive method. However, the weakness of the received backscattered signal is a major concern for this technique. Furthermore, there is a limitation to the size of tumour that can be detected. Therefore, this study analyzes the feasibility of ultra wideband (UWB) and microwave forward scattering radar (FSR) system for breast cancer detection. Two parameters which are UWB FSR radar cross section (UWB FS RCS) and received Doppler frequency profile were investigated. The results had shown a significant difference in terms of RCS amplitude of more than 2 dBm2 between normal and cancerous breast which can be used as a clue to detect the presence of tumor. The simulation shows a cancerous breast having Doppler frequency higher than the Doppler value in normal breast. Key words: Early breast cancer detection, ultra wideband (UWB) radar imaging.

The maximum-likelihood method is applied to determination of the target coordinates in forward-scattering radar systems with mobile stations. Estimates of the potential accuracy of measurement are obtained. It is shown that forward-scattering radars with mobile stations can ensure almost the same accuracy of measurement of the target coordinates as radar systems with stationary stations.

Recently, forward-scatter radars (FSRs) utilizing the Global Navigation Satellite System (GNSS) as a radiation source have gained increasing attention. The radar system enables aerial target surveillance by deploying multiple receiving nodes on the ground. It offers a low-cost and easily deployable solution. Therefore, how to deploy the receiving nodes to achieve efficient utilization of node resources is an urgent problem to be addressed. In this paper, a deployment method was proposed for receiving nodes in a single-transmitter and multiple-receiver configuration. First, the problem was reformulated as an optimal equal-circle covering problem via geometric approximation. A multi-objective optimization model was subsequently established with the objective functions of minimizing node cost and maximizing spatial detection area. Second, a method based on the Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm was introduced to obtain the sub-optimal solution of node cost, thereby reducing the computational complexity of the optimization process. Finally, an improved Non-dominated Sorting Genetic Algorithm II (NSGA-II) was proposed to derive the deployment schemes. Then, these schemes were ranked using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) based on the Entropy Weight Method (EWM). The results indicate that the proposed method can obtain the optimal deployment scheme compared to the existing method and enhance the diversity of the solutions.

3MT presentation at the 2016 Defence and Security Doctoral Symposium.Passive Bistatic Radar (PBR) systems use non-cooperative illuminations of opportunity to detect, localise and track targets. They have attracted a lot of interest in recent years because 1) they can be operated and deployed at a relatively low cost 2) they are difficult to detect and hence allow covert operations in a hostile environment and 3) because of the proliferation of illuminators of opportunity.Various illuminators of opportunity from analogue signal sources to digital ones, have been studied and exploited in recent years, and these include commercial broadcast systems, cellular base stations and local area networks. The aim of this research is to investigate the potential of PBR target detection in the presence of non-random signals emitted by a moving transmitter of opportunity and without the use of a reference channel. Typical transmitters of opportunity could be, for example, satellites carrying a SAR system. This research will include a study of the waveform properties, an assessment of target tracking performance and a set of experimental trials to demonstrate the feasibility of the proposed solution.

Monitoring of navigation in coastal areas is an important task for safety's guarantee. Nowadays a passive bistatic radar system is a point of interests of the scientific community in case of using different transmitters of opportunity. In this paper we consider passive bistatic radar with GNSS signals illumination. Here we suggest the structure of such system and algorithms of GPS signals processing. Also, the experimental suggestions are given. Our analytical research indicates the opportunity to use passive bistatic radar with GPS satellites as transmitters of opportunity as a coastal monitoring system.