ОСОБЛИВОСТІ ПОБУДОВИ БІСТАТИЧНОЇ РАДІОЛОКАЦІЙНОЇ СИСТЕМИ ПРИХОВАНОГО СПОСТЕРЕЖЕННЯ ЗА ЗОНОЮ ОХОРОНИ ВАЖЛИВИХ ДЕРЖАВНИХ ОБ’ЄКТІВ

Chapter 3 - Theory of monostatic and bistatic radar systems

In this paper, we have identified the system instability factors in a bistatic radar system using pulse chasing and considered their effects on the bistatic receiver's MTI(Moving Target Indication) improvement performance. The pulse chasing is a method to efficiently scan a restricted search area within the limited transmitter power and time in a bistatic radar and to track a series of transmitted pulses using the receiver beam which has ideally matched to the pulse propagation rate. In this paper, we have discussed the interrelationship between the pulse chasing and time and frequency/phase synchronization and described the effects of the identified system instability factors on two kinds of MTI filter configuration, single delay-line and double delay-line, in the bistatic radar. And also, we have confirmed that the overall system improvement is restricted by a lower improvement factor among identified them, and discussed the allowable tolerance of the time and frequency/phase synchronization in the bistatic system.

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.

Passive Bistatic radar is an effective and low-cost approach to surveillance in an area of interest. In many bistatic radar configurations, the impact of the Direct Signal Interference (DSI) is minimized by the physical locations of the transmitter and the receiver on the bistatic plane. In the satellite-based bistatic radar, the bistatic baseline is comparable to the distance from the transmitter to the target of interest; as such, the signal from the transmitter no longer dominates at the receiver. A feature that minimizes the computational complexity of the necessary algorithms to suppress DSI. Although the bistatic radar system is passive, it is susceptible to jamming when spotted. Interferers can affect the operation of a bistatic system if not adequately addressed. The existence of jammers in a bistatic environment can have a destructive effect on the surveillance channel. In specific radar modes, like track initiation and track maintenance, the Minimum Variance Distrotionless Response (MVDR) offers many advantages as it seeks to maximize power in the look direction. In this paper, we evaluate the performance of the combination of the MVDR and adaptive nulling in a satellite-based bistatic radar and Normalized Least Mean Square (NLMS) as a DSI canceller in a jamming environment.

The purpose of this letter is to solve the space-time off-grid problem caused by the extremely inhomogeneous clutter spectrum under the space/airborne bistatic system. For the estimation of inhomogeneous clutter spectrum, the method of sparse recovery (SR) is usually adopted. However, performance of sparse recovery may degrade since the real clutter point often does not fall in the center of the space-time grid. To deal with this issue, a local mesh splitting algorithm is proposed in this letter. First, select the space-time vector atoms which are most relevant to the residuals by subspace projection. Then, iterative local mesh splitting is performed around the selected atoms to match the real clutter points. Finally, the clutter subspace is reconstructed from all matched atoms selected by global and local iterations. The simulation results show that the method can obtain better accuracy with lower computational effort.

The paper is devoted to analysis of spatial resolution of a bistatic space-surface radar system with synthetic aperture of the transmitter. The system is shown to be able to measure two out of three coordinates of a target. Most natural for the measurements are target’s range R, which is evaluated based on the delay time of the received signal, and the projection x of the target radius vector on the direction of satellite’s trajectory, when the projection is measured by the Doppler shift of the received signal frequency. Formulas for the resolving capacity in terms of both these parameters are derived.

Calibration considerations and the performance analysis of an L-band airborne clutter measurement system are discussed. The measurement system is designed to collect simultaneous bistatic and monostatic clutter measurements in support of the hybrid bistatic radar (HBR) system. The analysis techniques used to define the experiment geometry and resulting resolution cells, calibration considerations, and the impact on the ability to determine clutter radar cross sections are described. The calibration techniques selected involved the transfer of calibration data from optimal geometries for calibration, to the geometries of interest in this program. >

In this contribution, we investigate on the coherent bistatic scattering generated by a radar system when illuminating a rough surface. Moving from the well-known scattering theory based on the Kirchhoff approximation, we propose an extended formulation of the Fung-Eom model, by introducing a higherorder expansion on the phase term of the impinging spherical wave. We demonstrate and discuss the importance of such correction for the accurate characterization of the coherent scattering generated in bistatic radar system. We give insight, for the first time, on the role played by both the antenna pattern and the wavefront sphericity in bistatic scattering in the whole incidence plane, not limiting the analysis to the backscattering and specular directions. This is particularly important for practical applications, such as the modeling of the scattering generated by sources of opportunity.

Mainlobe interference suppression has been a challenge in radar and communication systems for the last few decades. Here, a new anti-interference approach based on a bistatic radar system is proposed, and mainlobe interference is suppressed through cooperation of the two radars. The interference direction information of a single radar is extracted from the radar scene using multiple signal classification, and the location of the interference is obtained by the cross location method, which uses two different azimuthal angles of the interference. According to the azimuthal information of interference, the blocking matrix method is used to block mainlobe interference and protect the effective echo signal, and adaptive processing technology is adopted to suppress sidelobe interference. Finally, mainlobe interference can be cancelled by the received data of the two radars. A simulation verifies the performance of the model.

Radar(Radio-Detection and Ranging) has become very popular for several applications-in meteorology, defence, aircraft system and navigation system. The main purpose of the radar is to detect any object-moving or stationary. However, to get the micro-motion(internal motions of an object), we need to get micro-Doppler feature. In this report, the micro-Doppler feature of birds have been discussed using MIMO radar system as combination of several bistatic radar system. Also classification of multiple birds has been discussed in presence of noise and without noise. Also, adaptive signal processing technique (LMS,RLS,NLMS) has been discussed for clutter suppression . Finally application of LMS-Newton method has been discussed for clutter suppression.It can be seen that it has faster convergence compared to other algorithms.

This paper analyzes the synchronization of a bistatic synthetic aperture radar (SAR) system based upon a geostationary transmitter and small receive-only SAR systems mounted on airplanes or unmanned aerial vehicles (UAVs), namely GEO Spaceborne-Airborne Bistatic SAR. This paper will analyze and present our solution of the space synchronization, time synchronization, frequency synchronization and phase synchronization for the GEO Spaceborne-Airborne bistatic SAR respectively. It will first introduce the GEO Spaceborne-Airborne bistatic SAR system and geometry model briefly. Then possible solutions of the system synchronization will be discussed. It will introduce the synchronization scheme based on the direct path between the transmitter and receiver. It uses synchronization modules to realize the time and frequency synchronization. A mathematical model considering the time and frequency synchronization error is given and a phase error analysis is performed. Range and azimuth compressions of a single target are implemented by simulations.

A bistatic/monostatic HF surface wave radar (HFSWR) experiment was conducted using both the transmit and receive systems of the HFSWR at Cape Race, Newfoundland and the receive system of the HFSWR at Cape Bonavista, Newfoundland. While the HFSWR at Cape Race operated in the monostatic mode, the transmitter at Cape Race and the receiver at Cape Bonavista were synchronized via the Global Positioning System to operate in the bistatic mode. The results of the experiment show that the range of the clutter return from a specified layer in the ionosphere in the bistatic radar, and the range of the clutter return from the same layer in the monostatic radar follow, approximately, the relationship specified by the Pythagorean theorem, i.e., R=(h/sup 2/+(L/2)/sup 2/)/sup 1/2/, where h is the virtual height of the specified layer in the ionosphere, which is also the range of the clutter return in the monostatic radar case, and L is the separation between the transmitter and receiver in the bistatic configuration. Based on these observations, we calculated the coverage areas of bistatic HFSWR systems for water-entry areas along coastlines. The calculation shows that a bistatic HFSWR system has the potential to significantly improve the nighttime coverage area over a monostatic system, while, approximately, maintaining the same daytime coverage.

The SOPLAT (Single Observer Location And Tracking) technique has been used in bistatic systems, in which the transmitter only emits radar signal, and there is no need for synchronization between the transmitter and receiver. Under conditions of knowing PRF of radar signals emitted by the transmitter and the position of the transmitter, an algorithm, WMEKF (Weighted Modified Extended Kalman Filter) can be used to locate and track targets moving with constant speed by means of DOA and TOA measurement series. But for maneuvering targets, WMEKF algorithm is easily diverging, so it is not applicable. A new method for tracking maneuvering targets in bistatic systems with an independent receiver is described. Based on WMEKF algorithm, this paper introduces an adaptive tracking algorithm AWMEKF with a maneuvering detector for tracking maneuvering targets. Its performance for typical maneuvering target paths is evaluated by means of computer simulation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

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.

The problem of detection of multiple targets using a bistatic MIMO radar system is posed as a joint sparse signal recovery problem. We explore the potential of MIMO systems to locate targets in noisy environment with limited number of time samples, while the transmitted signals are not necessarily mutually orthogonal. Explicit enforcement of a joint sparse representation is motivated by a desire to obtain a sharp estimate of the targets that exhibits robustness in noisy environment. Numerical experiments demonstrate that the proposed strategy outperforms existing algorithms.