Adnan Orduyilmaz

FPGA-based match filter implementation in frequency domain using an overlap-add method

In this research, a real time matched filter is implemented on FPGA using an overlap-add method. The matched filter that increases the signal-to-noise ratio (SNR) for pulse compression and low probability intercept (LPI) radars is implemented in digital domain. This design is implemented on Xilinx Virtex-5 based processing board that samples in intermediate frequency (2.5 GHz). In the overlap-add method, we propose to design the matched filter by using two parallel FFT cores. Furthermore, the matched filter results are presented for different intra-pulse modulations.

Electronic attack techniques validation environment

In this article, the development of the electronic attack (EA) techniques validation environment is presented. EA techniques validation environment is a signal based closed hardware in loop which operates in intermediate frequency. By the development of this environment, radar and EA signals are processed on real time FPGA and the impact of radar and EA systems to each other are tested. Laboratory test environment provides cost/time advantage on both increasing the resistivity of radar systems to electronic attacks and the effectiveness of the electronic attack on the radar systems.

Real-time frequency parameter extraction for electronic support systems

In this research, real time automatic frequency parameter extraction methods for electronic support systems are implemented on FPGA. The frequency parameter is extracted by using digital instantaneous frequency measurement (DIFM) and fast fourier transform (FFT) methods. Estimation performances of these two different methods for different type of radars at different signal to noise ratios (SNR) are analyzed. This design is implemented on Xilinx Virtex-6 based processing board that samples in 2.5 GHz. Experimental results of the design for FPGA implementation are presented.

Real time wideband direction finding

In this paper, the developed FFT based interferometric direction finding of wideband radar threats for electronic support (ES) and electronic intelligence (ELINT) is presented. Using this method, target radar signal is separated from other radar signals using FFT. Phases of extracted radar signals for two or more channels are calculated. Angle of arrival of extracted radar signal is estimated with the phase differences of each channel pair at selected radar frequency. This method is also applied to frequency agile radars and pulse compression waveform radars. This method is implemented on FPGA platform in real time. For different SNR values, FFT sizes, radar signal instantaneous bandwidths simulation results and real time implementations are presented.

Multitab digital instantaneous frequency measurement receiver

This paper proposes an instantaneous frequency measurement (IFM) receiver structure for electronic support measure (ESM) systems. The performance of instantaneous frequency (IF) measurement improves as the IFM receiver delay increases. However, it is observed that the increasing delay introduces ambiguity to the IF measurement In order to resolve the ambiguity, an algorithm which uses the IFM receiver blocks of different delays in parallel is proposed. The IF measurement performance of the proposed IFM receiver is analyzed for different modulation types, pulse widths and signal to noise ratios.

Real-time instantaneous radar frequency measurement for pulse on pulse condition

In this research, a method which is implemented on FPGA for real-time extraction of the instantaneous frequency parameters of two simultaneous radar pulses (POP) in electronic support systems is presented. The frequency parameters of two different radars overlapped on time are extracted separately by using digital instantaneous frequency measurement (DIFM) method. Estimation performances of this method for different type of radars at different signal to noise ratios (SNR) are analyzed. This design is implemented on Xilinx Virtex-7 based processing board. Experimental results of the design for FPGA implementation are presented.

Real time Kalman filter implementation on FPGA environment

In this paper, implementation of real-time Kalman Filter on FPGA is presented. In the design, sequential Kalman Filter is selected that uses division under specific assumptions instead of using the inverse of the matrices intensively as in the Kalman Filter. This design can also be used in radar target tracking systems working on coastline that has crowded traffic. By comparing computer and FPGA results in the simulation platform, this design is verified.

Real time passive direction finding in FPGA environment

In this paper, FGPA implementations of amplitude and phase comparison direction finding methods are presented. In amplitude comparison direction finding (AC-DF), the power ratio between the receiver channels is compared with the values in the look-up-table that is generated using antenna patterns. In phase comprison direction finding (FC-DF), basically the phase difference is extracted between channels of the receiver and the angle of the arrival is estimated using the distance between the receiver antennas and wavelength of the received signal. In this paper, real time DF is enabled at the end of pulse duration. For various signal to noise ratio and the angle of arrivals, detailed analysis are experimented to measure the real time performances.

Real time intrapulse modulation extraction for electronic support systems

In this research, real-time intrapulse modulation extraction implementation on FPGA in electronic support systems is presented. In radar systems, intrapulse modulation methods are used to detect the targets at low SNR values and increase the range resolution of radar. In electronic support systems, performance of radar identification is increased by using modulation on pulse extraction. In this work, the phase and the frequency modulation types are extracted from radar pulses. At the end of the pulse duration, modulation information is obtained by using real time analysis. The analysis results that are created according to different SNR levels and modulations types are presented.

Real-time multiple velocity false target generation in digital radio frequency memory

Real-time generation of multiple velocity false targets, which is an effective electronic counter measure (ECM) technique against pulse-doppler radar, is studied. Classical ECM techniques employ generation of velocity false targets by switching single signal source in time. This paper proposes a time and frequency domain generation approach, which is more flexible and efficient in terms of resource allocation for increased number of false targets. ECM technique is implemented in Xilinx Virtex-6 SX475t FPGA platform. Velocity false targets with different parameter sets are tested both in FPGA platform and computer environment. It is shown that the proposed technique is effective in false target generation and suitable for real time implementation requiring lower resource allocations compared to time and frequency domain generation.