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The paper describes two approaches to model surface layer turbulence effects in a marine environment on microwave frequencies. One of the techniques is implemented within a hybrid ray optics parabolic equation model called the advanced propagation model (APM) and is based on a Monte Carlo approach. The second method is a direct computation of the log-amplitude variance of the signal. Predictions from...
Bistatic passive radar based on opportunity illuminators such as FM radio, is a hotspot in the domain of radar. The direct/multi-path signals cancellation techniques(DSC) have been discussed by many scholars. These considered algorithms adopt a single-stage adaptive filter processor frame, have sufficient performance in the cancellation of the direct/multi-path interference signals from the selected...
Passive radar using GSM cellular mobile communication signal had been demonstrated to be feasible for short-range moving target measurements. This paper presents some new results of aircraft measurements with enhanced performance. It is shown that the operation range of GSM-based passive radar can be substantially larger than the coverage of one normal base station cell that is allocated for mobile...
The geometry of inverse synthetic aperture radar (ISAR) imaging suggests in principle a tomographic approach to the reconstruction of a 2D projection of an object illuminated by a radar signal. In theory this is straight forward, but the computational load of such reconstructions have in stead led to the use of fast Fourier transforms (FFTs) on a Cartesian grid. Using FFTs directly in ISAR imaging...
Amongst all the functions constituting the TRMC (translational and rotational motion compensation) processing chain developed by Galileo Avionica for real-time high-resolution radar imaging, the RMC (rotational motion compensation) function is doubtless the heaviest by the point of view of required computing processing load. In this paper the possibility to partition and to parallelize across several...
A new efficient method to obtain high resolution ISAR images in the case of missing observation data is presented. The available data segments are modeled by 2-D linear prediction of 2-D Cartesian frequency spectra using 2-D orthogonal lattice filters. Then the prediction models are used to estimate the missing data segments. It is shown that the IFT processing of the resulting data achieves better...
We present a novel receiver structure for the detection and parameter estimation of linear frequency modulated signals. The proposed structure is based on the relations between the fractional Fourier transform and the ambiguity function. It has been shown that the optimal ML receiver, which is the peak detector in the ambiguity plane, can be implemented at a reduced search complexity with the proposed...
The capabilities in imaging for forward-looking radar receivers are severely limited so far. This application gap is especially valid for monostatic radars due to their problem producing a significant Doppler shift orthogonal to the direction of illumination. So a two-dimensional resolution of an area of investigation is nearly unattainable. Here bistatic configurations with separated receiver and...
This paper describes the design, development and test of a passive covert radar (PCR) exploiting a single non cooperative frequency modulated (FM) commercial radio station as its transmitter of opportunity. The system has been conceived in order to detect low flying and low radar cross section (RCS) targets even in disturbed and hostile electromagnetic environments. Preliminary measurements of the...
Helicopters are essential for any mission of humanitarian or assisting nature in disaster areas. Very often they have to cope with missing infrastructure and extreme environmental conditions. Besides darkness and adverse weather, dust and snow are two of the most dangerous conditions for helicopter landing. At the time being, helicopter pilots have no adequate sensors to get information on height...
This paper briefly discusses a procedure to measure the radar cross section (RCS) of small boats at 94 GHz. It describes an extremely simple and moderately low cost set of hardware that was used to perform these measurements. An analysis of the calibration method including measurements of reference corner reflector returns and those from the sea were made throughout the trials. Results include polar...
Digital audio/video broadcasting (DAB/DVB-T) is already available in a large area of Europe. The advantage of using these signals for passive air surveillance is the disposability of a large range of illuminators sending an easily decodeable digital broadcast signal. In the considered multi-static scenario, one observer provides bistatic time difference of arrival (TDoA) and Doppler measurements....
Radar signatures of complex targets for different frequencies, aspect angles and target positions are needed in various radar application areas. In addition, specific scattering centers of complex real radar targets have a strong impact on the overall signature of the target. However, measurements are mostly inefficient for providing the required information and for studying the behaviour of such...
In a world, where terrorism is threatening human life in particular that of those forces and civilian personnel who are involved in peace keeping and peace enforcing missions, the defence against snipers is a necessary safety demand. For this purpose sensor systems based upon various principles are in use and still under development. Among those acoustic and electro optical sensors are the most common...
MIMO (multiple-input multiple-output) radar refers to an architecture that employs multiple, spatially distributed or colocated transmitters and receivers. The widely spaced antenna structure suggests unique features that set MIMO radar apart from other radar systems, making it strongly related to MIMO communications. The widely separated transmit/receive antennas capture different aspects of the...
Derived from statistical conditional optimization criteria, the auxiliary-vector (AV) detection algorithm starts from the target vector and adding non-orthogonal auxiliary vector components generates an infinite sequence of tests that converges to the ideal matched filter (MF) processor for any positive definite input autocorrelation matrix. When the input autocorrelation matrix is replaced by a conventional...
Helicopter classification capability is a desirable feature on air defense radars, as a way of distinguishing friends of foes. However, it is still a challenging task for any radar system. The classical method for helicopter classification is the L/N-quotient method, where two signal features are measured: time between peaks and blade tip velocity. Unfortunately, these features are difficult to measure...
Glaciers in several parts of the world are reported to be retreating and thinning rapidly over the last decade. Radar instruments can be used to provide information on the internal and basal conditions of large and small ice masses. Radars operating in the lower part of the HF spectrum are required for sounding temperate glaciers. Also, low-frequency sounders are useful for measuring thickness of...
The performance of a target recognition method based on template matching depends on the quality of the template database to a large extent. This paper introduces a method of establishing an extensible template database of range profiles based on the minimum entropy rule. The new method guarantees the quality of the template database from two sides: the signal-to-noise ratio and the completeness of...
New generation of HF skywave radars moves toward 2D array solution to get high signal to noise ratio (SNR), low probability of intercept (LPI), precise electronic scanning, faster scanning time. Critical elements for the design of such a system are radar configuration, antenna design, transmission waveforms and architecture, signal processing, radar management and control system. The goal of this...
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