V. Behar

Adaptive CFAR PI Processor for Radar Target Detection in Pulse Jamming

A new parallel algorithm for signal processing and a parallel systolic architecture of a CFAR processor with adaptive post detection integration (API) are presented in this paper. The processor proposed is used for effective target detection in a single range resolution cell of a radar when echoes from small airborne targets are performed in conditions of pulse jamming. The main property of the algorithm proposed is its ability automatically to determine and censor the unwanted samples corrupted by pulse jamming in both the two-dimensional reference window and the test cell before noise level estimation. In such a way the influence of pulse jamming environment over adaptive thresholding is reduced to minimum. Statistical analysis of the algorithm for target detection shows that the signal-to-noise ratio losses are insignificant even if the power and the frequency of pulse jamming are extremely high. The systolic architecture of the CFAR API is designed. Basic measures of the systolic architecture are the number of processor elements, the computational time and the speed-up needed for real-time implementation.

Hough detector with adaptive non-coherent integration for target detection in pulse jamming

It is shown that the Hough transform with binary integration of the data in parameter space may be used for improvement of target detection in the presence of strong pulse jamming (PJ). The algorithm proposed may be used for effective detection of small airborne targets whose trajectories are straight radial lines. The expressions for detection probability evaluation are derived for a target model according to the Swerling case II. The expressions obtained are applied to the typical surveillance radar. The results show that the algorithm proposed allows one sufficiently to reduce the losses in the signal-to noise ratio (SNR) in comparison to the CA CFAR detector with non-coherent integration when the PJ intensity is very strong. It is shown that the algorithm proposed is very effective even if the probability of PJ appearance is very high.

Marine target classification and parameter estimation using Forward Scattering Radar

In this paper a possible original method for rough classification of marine target, through estimation of the velocity and linear size of moving sea objects using Forward Scattering Radar (FSR) system is present. The target velocity and size are estimated by cross-correlation between instantaneous frequencies of the input signal and the predefined reference signal. The estimation algorithm is tested on the base of real experimental signal from the boat moving with a given velocity, that have been obtained by the team from Birmingham University using Forward Scattering Radar.

Techniques for CFAR radar image detection in pulse jamming

The presence of strong pulse jamming in a reference window used by Cell-Averaging CFAR detectors for noise power estimation can cause drastic degradation in performance even if the CA CFAR detectors employ binary integration. The technique for pulse jamming suppression discussed in this work is the use of filters matched to a broadband transmitted pulse in combination with an excision CFAR detector where strong samples are excised from the reference window prior to the cell-averaging operation. In particular, the excision CEAR detector with binary integration is considered in situation when the duration of broadband pulse transmission with phase-code-modulation and the average repetition interval of pulse jamming are commensurable. The mathematical formulas for analysis of the excision CFAR binary integration processor are derived for the case of broadband pulse transmission in the presence of pulse jamming. In addition, the possibility for real-time implementation of the excision CFAR binary integration processor over a multiprocessor system based on signal processors ADSP-21062, is analytically evaluated. The computation cost is defined as the number of signal processors and computation steps necessary for real-time implementation of the excision CFAR binary integration processor.

Forward scatter radar detection and estimation of marine targets

In this paper we research original structure of the Bistatic Forward Scatter Radar detector and signal parameter estimator of the marine targets at the background of a sea clutter. The time duration, power, energy and the maximum of the Doppler frequency for MISL and other boat are estimate for many trails. These results will make possible to be used for the data mining classification with the WEKA software. We propose and original structure of the FSR Rough Target Classifier, of the marine targets at the background of a sea clutter. Using the CFAR processor approach for Target detection and parameter estimation of the first minimum and maximum frequency from Power Spectrum Density, we receive the signal parameters in the FSR in the real time. On base this signal parameters, we calculate target parameters velocity and length from two equations, for velocity of targets in bistatic systems and for length of FSR target propose by Cherniakov. These parameters, length and velocity, we may to use for rough targets classification, because they consists all information about the boat. The research algorithm is investigated on the base of real data records that have been obtained by the team from Birmingham University and Sofia University using Forward Scattering Radar.

CFAR radar image detection in pulse jamming

It is shown that the appearance of strong pulse jamming in the reference window causes drastic degradation in the performance of CA CFAR (cell averaging constant false alarm rate) binary integration processors. The technique for pulse jamming suppression employed in this work is the use of filters matched to a broadband pulse with a large time-bandwidth product. In particular, the situation when the duration of broadband pulse transmission with phase-code-modulation and the average repetition interval of pulse jamming are commensurable, is considered in the paper. The mathematical formulas for analysis of the conventional CA CFAR binary integration processor in conditions of pulse jamming are derived for the case when the broadband pulse transmission is used. In addition, the possibility for real-time implementation of the CA CFAR binary integration processor over a multiprocessor system based on signal processors ADSP-21062, is analytically evaluated. The computation cost is defined as the number of signal processors and computation steps necessary for real-time implementation of the CA CFAR binary integration processor.

Moving Target FSR Shadow Detection Using GPS Signals

Forward Scatter GPS (FS-GPS) radio shadows obtained from different objects are investigated in this article. FS radio shadow is essential physical phenomenon, which can be used to extract some useful information about the objects that generate it. Registration of FS-GPS radio shadows from moving and stationary objects is performed using a small commercial GPS antenna and mobile and stationary receiver. Topology of the experiment meets the requirements for the appearance of the FS effect. The results presented in this article show that from FS-GPS radio shadows of different objects can be extracted information about the parameters of the object (size, speed and direction of movement, distance to the receiver). The information obtained can be used in various applications like those in classic radar, including radio barriers, security, classification and identification of moving and stationary objects.

Detection and estimation of pulsar signals for navigation

The paper focuses on scientific issues related to new application of pulsar signals for airplane-based navigation. A possible algorithm for processing of pulsar signals that consists of epoch-folding, matched filtering and detection is proposed and evaluated in this paper. The algorithm proposed is verified using the real experimental data obtained from the radio observatory Dwingeloo, the Netherland. The serious trouble in this study is that the total number of the input data within a repetition period is much more of the number of samples in a pulsar template taken from the EPN database. Therefore have been developed and evaluated two new algorithms for epoch-folding, which not only improve Signal-to-Noise Ratio of pulsar signals but as well reduce the number of samples of the output signals to the required number.

Sparse array optimization by using the simulated annealing algorithm

Sparse synthetic transmit aperture (STA) imaging systems are a good alternative to the conventional phased array systems. Unfortunately, the sparse STA imaging systems suffer from some limitations, which can be overcome with a proper design. In order to do so, a simulated annealing algorithm, combined with an effective approach can used for optimization of a sparse STA ultrasound imaging system. In this paper, three two-stage algorithms for optimization of both the positions of the transmit sub-apertures and the weights of the receive elements are considered and studied. The first stage of the optimization employs a simulated annealing algorithm that optimizes the locations of the transmit sub-aperture centers for a set of weighting functions. Three optimization criteria used at this stage of optimization are studied and compared. The first two criteria are conventional. The third criterion, proposed in this paper, combines the first two criteria. At the second stage of optimization, an appropriate weighting function for the receive elements is selected. The sparse STA system under study employs a 64-element array, where all elements are used in receive and six sub-apertures are used in transmit. Compared to a conventional phased array imaging system, this system acquires images of better quality 21 times faster than an equivalent phased array system.

Detection and classification of objects from their radio shadows of GPS signals

The paper focuses on scientific issues related to new application of GPS in radar networks using the effect of Forward Scattering (FS) of electromagnetic waves to detect, locate and classify objects by their GPS radio shadows. The aim of the paper is to make experimental studies of GPS radio shadows of different objects irradiated by GPS signals and to develop methods and algorithms for automatic detection, estimation and classification of the shadows of these objects. The practical utility of the results obtained is to use a specific processing of the received signal in the GPS receiver, then to use the extracted information for positioning and classification of moving objects; for accurate assessment of the geographic location of fixed objects by method triangulation in systems for transport management, security of zones, subsequent identification of the detected objects from digital geographical maps.