Electronic Warfare Receivers Research Articles

Approach of Pulse Parameters Measurement Using Digital IQ Method

 Abstract—Electronic Warfare (EW) systems measuring the radar parameters using conventional method can't preserve phase information of the incoming Radio Frequency (RF) signals. Conventional methods does the measurement using detected video signal or envelope of the RF. Proposed method does the measurement using intermediate frequency (IF) signal which is the down converted signal of RF signal. This method preserves the phase information because the intrapulse and interpulse measurements are carried out using the IF signal. The Matlab simulation is carried out for the intrapulse analysis and results are presented and discussed. The comparison is given between conventional method and proposed method for Radar EW systems. Initially the measurement of radar pulse parameters being carried out using the envelope of the down converted IF or RF signal. This envelope is nothing but it is video signal. In the process of envelope detection, the phase information of the signal is lost. Therefore these methods are not useful where phase information is to be preserved. The proposed EW receiver is shown in the Fig. 2. The next generation EW receiver is the superhet receiver. The superhet receiver downconverts the RF signal into the fixed IF signal of the required bandwidth. The bandwidth is varied depending upon the requirements. The superhet receiver has the advantage of sensitivity due to its limited bandwidth. The proposed method of intrapulse analysis works alongwith the superhet receiver. The IF generated from the superhet receiver is digitized. The frequency translation is carried out on these digitized IF samples and filtered out the highest component. This method measures the rise time and fall time and it also carries out measurement of parameter variations within the pulse.

Approaches towards Implementation of Multi-bit Digital Receiver using Fast Fourier Transform

This paper compares different digital receiver signal processing schemes as applied to current ESM/RWR systems. The schemes include fast fourier transform (FFT)-based, FIR filter-based and mixed architectures. Use of polyphase FFT and IIR filters is also discussed. The specifications and signal processing requirements of a modern digital electronic warfare (EW) receiver are discussed. The design procedures and architectures for all the schemes are brought out. The tradeoffs involved in selection of different parameters for these schemes are also discussed. The digital receiver schemes are modeled and analyzed for different metrics such as, Parameter measurement accuracies, Pulse handling capability, Frequency separation capability, Number of multipliers required for implementation etc. The analysis is done for a 500 MHz BW digital receiver and assumes 8 bit ADC in the front end. The results obtained for the comparison are discussed in the paper. Limited simulations show that overlapped FFT scheme is a better approach for digital receiver processing. Defence Science Journal, 2013, 63(2), pp.198 -203 , DOI:http://dx.doi.org/10.14429/dsj. 63.4264

Modeling and Analysis of LPI Radar Signal

Radar Emitter Signal recognition is one of the key procedures of signal processing in Electronic Warfare (EW) Receiver. As there is an intense growth in the activities of modern Electronic Warfare, advanced radars are increasing and becoming main component of radars gradually. These modern radars called Low Probability of Intercept (LPI), use different complex waveforms to mask their presence from the enemy while accomplishing their mission. These waveforms cannot be detected by the use of traditional recognition algorithms and methods thus posing a major challenge to the Electronic Warfare designer. This paper presents simulation of different types of LPI signals, generation of those signals and development of Time Frequency Algorithm to analyze those signals.

Electronic Warfare Receiver with Multiple FFT Frame Sizes

An electronic warfare (EW) receiver based on fast Fourier transforms (FFTs) with different frame sizes is presented. With a given sampling frequency, an FFT-based EW receiver can improve its frequency estimation by increasing the FFT frame size; however, such an increase has detrimental effects on its time-of-arrival and pulse width estimations. By applying multiple FFTs with different frame sizes, the proposed EW receiver can achieve high time and frequency resolutions simultaneously.

High-Performance Photonic Microwave Downconverter Based on a Frequency-Doubling Optoelectronic Oscillator

Photonic microwave downconversion based on an optoelectronic oscillator (OEO) is interesting because the local oscillator signal is directly extracted from the RF signal, but some of the frequency components in the RF signal would leak to the oscillation signal due to the limited rejection ratio of the electrical bandpass filter in the OEO, which degrades the downconverted signal. In this paper, a high-performance photonic microwave downconverter based on a frequency-doubling OEO (FD-OEO) is proposed and demonstrated to avoid the direct degradation from the RF signal. A 20-GHz RF signal with 1-Gb/s data modulation is successfully downconverted by the FD-OEO. The phase noise at 10-kHz frequency offset of the extracted RF carrier by the FD-OEO is 14 dB lower than that extracted by a conventional OEO, and the receiver sensitivity of the downconverted signal has a 1.173-dB improvement. The downconverter needs only low-frequency devices, which may find application in phased-array antenna arrays, electronic warfare receivers, avionics, and wireless communication systems.

Specifying Upper Bounds on Phase Noise in Phase-Locked Oscillators in Electronic Warfare Systems–Part I [Application Notes

The purpose of this article is to present simple relations that allow one to find the upper bound on the phase noise of a phase-locked oscillator (PLO), its frequency stability, mean-square incidental phase noise modulation (Φ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) and phase jitter. Simple closed-form equations are derived that are not intend ed as design tools, but are intended to establish upper limit specifications for the phase noise levels of PLOs used in wideband electronic attack (EA) and electronic warfare (EW) systems. A block diagram of a hypothetical system is used to illustrate how an EA system is susceptible to degradation due to phase noise of PLOs. This part presents a technique to model the phase noise spectral density of a manufacturer's PLO. Based on the manufacturer's specifications, the model allows the prediction of the total phase noise, phase jitter and predicted frequency uncertainty (Allan Variance) of the PLO considered. Part II (to appear in the February 2012 issue of IEEE Microwave Magazine) will present a technique to calculate the common-mode coupling of the oscillator phase noise into the following intermedi ate frequency (IF) section of a mixer. The coupled noise may increase the noise figure of a receiver. A method to estimate the increase in phase noise due to vibration will also be presented. Some basic definitions and performance characteristics are described in "Performance Metrics for Electronic Warfare Receivers".

Implementing EW Receivers Based on Large Point Reconfigured FFT on FPGA Platforms

This paper presents design and implementation of digital receiver based on large point fast Fourier transform (FFT) suitable for electronic warfare (EW) applications. When implementing the FFT algorithm on field-programmable gate array (FPGA) platforms, the primary goal is to maximize throughput and minimize area. This algorithm adopts two-dimension, parallel and pipeline stream mode and implements the reconfiguration of FFT's points. Moreover, a double-sequence-separation FFT algorithm has been implemented in order to achieve faster real time processing in broadband digital receivers. The performance of the hardware implementation on the FPGA platforms of broadband digital receivers has been analyzed in depth. It reaches the requirement of high-speed digital signal processing, and reveals the designing this kind of digital signal processing systems on FPGA platforms.

CONSTELLATION SHAPE AS A ROBUST SIGNATURE FOR DIGITAL MOULATION RECOGNITION

Modulation recognition plays a key role in analysis of the intercepted signals by electronic warfare receivers. A hybrid approach for modulation recognition is introducd. This approach consists of two main classification and decision algorithms. The first is a pattern recognition algorithm for reconstruction of the constellation shape as a stable modulation signature of the intercepted signal. The second is a threshold detection logic algorithm for identification of the modulation type of the intercepted signal. These two algorithms are connected through a feature extraction procedure The complex envelope, which represents both the in phase and quadrature phase components of the received signal after carrier estimation [1,2,11] is utilized as the input of the pattern recognition algorithm. The proposed algorithm shows a robust behavior for identification of single tone digital modulated signals for a relatively low signal to noise ratio (SNR) compared with the ordinary modulation recognition algorithms. Experimental results are shown for various modulation standards including M-ASK, M-PSK, and M-QAM only for M= 8 or 16, received through an AWGN channel and in the presence of carrier recovery errors.

Deinterleaving of radar signals and PRF identification algorithms

Electronic warfare (EW) receivers are passive receivers which receive emissions from other platforms, and do certain analysis on these emissions. Some EW receivers receive radar pulses, measure the parameter of each pulse received and group the pulses that belongs to the same emitter together to determine the radar parameters for each emitter. These parameters are then compared with values stored for known radar types, to identify the emitter type. Two parts are focused, emitters deinterleaving and PRF-type identification. The deinterleaving is done through parameters clustering. Two parameters are selected for clustering direction of arrival and radio frequency. A self-organising neural network called Fuzzy ART is proposed for clustering. This algorithm has a very good clustering quality and can run in real-time applications.The PRF-type identification is done through time-of-arrival (TOA) analysis. Three previously presented algorithms are combined in new scheme to do the TOA analysis (or PRF-type identification). These algorithms are difference TOA histogram, TOA folding histogram and sequence search algorithm. The complete proposed system has been tested using three different tests. These tests are simple PRI test, jittered PRI test and staggered PRI test. The proposed system identifies up to 90 simple emitters, 20 jittered emitters and 20 staggered emitters. In all tests, the data were simulated and generated using software.

HIGH-SPEED, LOW-POWER DIGITAL AND ANALOG CIRCUITS IMPLEMENTED IN IBM SiGe BiCMOS TECHNOLOGY

Under the auspices of Defense Advanced Research Project Agency's Microsystems Technology Office (DARPA/MTO) Low Power Electronics Program, the Mayo Foundation Special Purpose Processor Development Group is exploring ways to reduce circuit power consumption, while maintaining or increasing functionality, for existing military systems. Applications presently being studied include all-digital radar receivers, electronic warfare receivers, and other types of digital signal processors. One of the integrated circuit technologies currently under investigation to support such military systems is the IBM Corporation silicon germanium (SiGe) BiCMOS process. In this paper, design methodology, simulations and test results from demonstration circuits developed for these applications and implemented in the IBM SiGe BiCMOS 5HP (50 GHz fT HBTs with 0.5 μm CMOS) and 7HP (120 GHz fT HBTs with 0.18 μm CMOS) technologies will be presented.

Analysis and characterization of a monobit receiver for electronic warfare

Detection of simultaneous signals and real-time operation are basic characteristics in broadband electronic warfare (EW) receivers. A digital channelized monobit receiver represents an attempt to achieve both features at the expense of low instantaneous dynamic range. This paper presents a detailed theoretical and experimental analysis, and characterization of the performance of this promising receiver composed of a monobit analog-to-digital converter (ADC) and a filter bank based on a monobit implementation of the discrete Fourier transform (DFT).

Prijemnici za elektronski rat

Prijemnici za elektronski rat

Cryogenic electronics in advanced sensor systems

Cryogenic Electronics technologies are discussed from the standpoint of meeting sensor performance requirements. Capabilities that are provided by cryogenic electronics are described. Radar and Electronic Warfare (EW) Systems requirements are based on the need to detect and track targets in the presence of clutter and jamming signals. Radars must transmit high fidelity signals, and receive returns with high fidelity and wide dynamic range for Doppler Processing, to discriminate targets from clutter and jamming. Requirements are translated into radar specifications: transmitter, receiver, antenna array, and other components must produce low phase noise. The receiver and analog to digital converter (ADC) need wide linear dynamic range. HTS technology provides key devices to achieve phase noise supression and large signal dynamic range. Examples include: HTS resonators generate stable reference signals in the radar; switchable preselectors remove out of band jamming; HTS circuits enable digital to analog converters (DACs) and ADCs to provide direct synthesis of complex waveforms and digitization of received signals. EW System requirements are high dynamic range reception, and real-time signal processing; they must be wide-band and recognize a diverse set of waveforms. An HTS switchable preselector and delay line provide the front end for an advanced EW receiver and processor. The application of HTS technology to Radar and EW Systems will be addressed, and progress to date in development of analog and digital HTS devices will be described. >

Direction-finding performance of a Ka-band ESM receiver

Although development of electronic warfare (EW) receivers has begun to address the need to detect millimeter wave radars, very little ESM (electronic support measures) performance data have been provided to the system engineering community. This has partially been a result of the sensitivity of some millimeter wave applications. This paper provides a sample of direction-finding (DF) measurements derived from tests carried out on an advanced development model (ADM) millimeter wave (28-40 GHz) ESM receiver using an outdoor test range. DF accuracies of 5-6/spl deg/ r.m.s. are demonstrated as being readily attainable at Ka-band using conventional amplitude comparison monopulse techniques combined with high probability-of-intercept and large instantaneous dynamic range.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Reduction of aliasing ambiguities through phase relations

A method for digital determination of a single frequency from a sine wave sampled at less than the Nyquist rate is discussed. The method makes use of phase shift information to eliminate the aliasing ambiguity. Multiple sampled data are required to eliminate ambiguity completely. Computer modeling using simulated data corrupted by uncorrelated Gaussian noise was used to verify the approach. The results demonstrate that the frequency of an input sine wave can be correctly identified. This approach can be applied to electronic warfare (EW) receivers to increase their input bandwidth.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A review of current and future components for electronic warfare receivers

This paper addresses the role of conventional and new components in passive electronic warfare (EW) receivers. The various areas of EW are defined before restricting the discussion predominantly to the radar intercept problem at microwave frequencies. The operational parameters of conventional components are then reviewed including the multiplexer; crystal video, instantaneous frequency measurement (IFM), and scanning superheterodyne receivers. The significance of modularity, digital control, and hybrid combinations of components is highlighted. A brief description follows of the operational Cutlass EW equipment. New components based on surface-acoustic waves (SAW) and acoustooptic (AO) Bragg cells are then presented and their particular importance in channelized receivers, IFMs, and microscan receivers noted. Finally, a number of conclusion5 are drawn covering likely trends in EW receivers and the need for continuing development of large-scale integrated (LSI) circuits for signal sorting and overall digital management.

A Review of Current and Future Components for Electronic Warfare Receivers

This paper addresses the role of conventional and new components in passive electronic warfare (EW) receivers. The various areas of EW are defined before restricting the discussion predominantly to the radar intercept problem at microwave frequencies. The operational parameters of conventional components are then reviewed including the multiplexer; crystal video, instantaneous frequency measurement (IFM), and scanning superheterodyne receivers. The significance of modularity, digital control, and hybrid combinations of components is highlighted. A brief description follows of the operational Cutlass EW equipment. New components based on surface-acoustic waves (SAW) and acoustooptic (AO) Bragg cells are then presented and their particular importance in channelized receivers, IFM's and microscan receivers noted. Finally, a number of conclusions are drawn covering likely trends in EW receivers and the need for continuing development of large-scale integrated (LSI) circuits for signal sorting and overall digital management.