FMCW Radars in the Perspective of EW (CSTD2021)

2007

2006

This paper considers the problem of detecting and classifying a radar target against jamming signals emitted by electronic countermeasure (ECM) systems. The detectionclassification algorithm proposed here exploits the presence in the jamming spectrum of spurious terms due to phase quantization performed by the radio frequency digital memory (DRFM) device. A pulse Doppler radar transmits a coherent signal that is produced by modulating a complex sinusoid with a pulsed waveform. For ease of treatment, we assume here that the signal is infinite in time. Using the infinite time assumption, the pulsed waveform can be written as

IEEE Transactions on Microwave Theory and Techniques, 2018

A frequency-modulated continuous-wave (FMCW) radar interference mitigation technique using the interpolation of beat frequencies in the short-time Fourier transform (STFT) domain, phase matching, and reconfigurable linear prediction coefficients estimation for Coherent Processing Interval processing is proposed. The technique is noniterative and does not rely on algorithm convergence. It allows the usage of the fast Fourier transform (FFT) as the radar's beat-frequency estimation tool, for reasons such as real-time implementation, noise linearity after the FFT, and compatibility with legacy receiver architectures. Verification is done in range and in range-Doppler using radar experimental data in two ways: first by removing interferences from interference-contaminated data and second by using interference-free data as the reference data, and processing it-as if it had interferences-using the proposed technique, inverse cosine windowing and zeroing for comparison. We found that processing with the proposed technique closely matches the reference-data and outperforms the inverse cosine windowing and zeroing techniques in 2-D cross correlation, amplitude, and phase average errors and phase root-mean-square error. It is expected that the proposed technique will be operationally deployed on the TU Delft simultaneous-polarimetric PARSAX radar. Index Terms-Frequency-modulated continuous wave (FMCW), linear prediction (LP), multiple-input and multipleoutput radars, polarimetric radars, radar interference mitigation techniques. I. INTRODUCTION F REQUENCY-modulated continuous-wave (FMCW) radars might suffer from interferences from other radars operating within their vicinity, as in multiple-input and multiple-output radar networks and in automotive scenarios, or from themselves as in the case of fully polarimetric radars with dual-orthogonal signals [1], where there is a leakage between two mutually orthogonal channels (cross-channel interference). In deramp FMCW radars (stretch-processing), targets' range is deduced from beat-frequency estimation. Processing interference-contaminated beat frequencies with fast Fourier transforms (FFTs) yields poorer radar detection, due to undesired artifacts such as a noise-floor level increase in range

IRJET, 2023

This study is about the FMCW Radar System Simulation for detecting multiple targets. The FMCW Radar system is a type of radar system that is capable of providing high range resolution and protection against electronic warfare techniques. It does this by emitting a frequency modulated chirp signal from a transmitting antenna, which allows the frequency of the signal to increase or decrease linearly over time. This modulation technique improves the range resolution of the radar system. Therefore, FMCW Radar system is widely used in military applications. The study aimed to improve the range resolution of the FMCW Radar system by optimizing the modules used in the system and processing the transmitted and received signals with advanced algorithms such as CA-CFAR and MUSIC. For evaluating the effectiveness of the system, the study created an environment with multiple targets and conducted a modeling and simulation study to determine the distances, velocities, and angular positions of the targets.

IEE Proceedings F Radar and Signal Processing, 1991

The paper describes the waveform analysis for an experimental long-range highfrequency radar system with a design capability for over-the-horizon detection of ocean surface targets up to 400 km from shore with a range resolution of 400m. Motivated by the need to maximise the transmitter duty cycle in order to detect long-range targets, the radar is based on a frequency modulated interrupted continuous wave (FMICW) type waveform. The interrupt sequence, which is necessary for a high power monostatic operation, complicates the analysis of the radar performance in terms of the ambiguity function (AF). This paper analyses the range dependent AF of FMICW waveforms and proposes practical interrupt sequences for the synthesis of desired AFs. Paper 8091F (ElS), first received 1st June and in revised form 29th

Millimeter-wave (mm-wave) frequency modulated continuous wave (FMCW) radars are increasingly being deployed for scenario perception in various applications. It is expected that the mutual interference between such radars will soon become a significant problem. Therefore, to maintain the reliability of the radar measurements, there must be procedures in place to mitigate this interference. This paper proposes a novel interference mitigation technique that utilizes the pulse compression principle for interference compression and mitigation. The interference in the received time-domain signal is compressed using an estimated matched filter. Afterward, the compressed interference is discarded, and the signal is repaired in the pulse-compressed domain using an autoregressive (AR) model. Since the interference spans fewer samples after compression, the signal can be restored more accurately in the compressed domain. Real outdoor measurements show that the interference is effectively suppr...

International Conference on Aerospace Sciences and Aviation Technology, 2001

This paper presents the mathematical analysis of a proposed jamming technique used against IAC monopulse radar. The idea of this technique is to repeat the radar signal with change in its amplitude and phase (deception jamming signal) to produce an angular error in the target tracker. This error changes for different values of amplitude ratio and phase difference w.r.t the target signal. In the generated deceptive jamming signals, the change in the amplitude ratio makes large effect than the change in the phase difference on the real part of the complex measured error angle. The real value of the complex measured angle due to jamming with constant phase difference and different amplitude ratio has large variation at amplitude ratio less than three. This value converges to the value of the angle of the false target for higher amplitude ratio. There is no jamming effect at amplitude ratios less than one and for some values of phase difference. At these values, the measured angle equals to the angle of the real target. At least two jamming signals are required to have the complex error jamming angle to overcome the ECCM techniques that might be used by the target.

Progress In Electromagnetics Research Symposium, 1993

This paper presents a detailed analysis of the performance limits of wideband FMCW radar. This radar system has unique noise and distortion effects, because the received signals overlap temporally. The major sources of noise are: Electronic noise which arises from the RF, IF amplifiers, the mixer, the sweep oscillator's AM and FM noise and the AID quantization noise. Electronic distortion which arises from intermodulation, the finite sampling time aperture, jitter and the finite sampling frequency. Propagation Distortion which includes internal and external clutter, multi-path and multiple scattering, the effect of the near-field antenna pattern and the target cross-section fluctuations with frequency, dispersion, finite geometrical aperture effects and antenna leakage.

IOP Conference Series: Materials Science and Engineering, 2019

Frequency Modulated Continuous Wave (FMCW) radars get target range and Doppler information by extracting the target beat frequency and phase exchange based on the well-known Two-Dimensional Fast Fourier Transform (2D-FFT) processing algorithm. Target whose beat frequency does not lie on the FFT grids suffers from great detection degradation. Doubling the number of FFT points, and consequently, the hardware processing complexity is a common solution to solve this problem. In this paper, a proposed method to increase the detection performance of these targets and avoid increasing system complexity is introduced. The proposed method depends on applying a proposed filter following the first and second FFT algorithms. The filter order and weights are chosen so that only one peak form the adjacent peaks of off-pin targets are distinguished. The superiority of the proposed method over the traditional one is validated for different scenarios through the Receiver Operating Characteristic (ROC).

IEEE Access

This paper introduces a novel approach to incorporate the time compression overlap-add (TC-OLA) technique used in communication systems into linear frequency modulation pulse compression (LFM-PC) radar systems. This technique significantly boosts the signal-to-noise ratio (SNR) and provides a robust processing gain compared with the traditional radar LFM-PC systems. In addition, TC-OLA provides a better immunity against powerful jamming techniques. At the transmitter side, we divide a digitized LFM chirp signal into a controlled number of overlapping segments. We then speed up each segment by increasing the sampling rate to account for the segment overlap. At the receiver side, we apply OLA to reconstruct the signal with a much higher gain. To simulate and evaluate the performance of the new system, we extend the conventional LFM-PC radar model, which includes matched filter (MF) processor, moving target detector (MTD), and two common constant false alarm rate (CFAR) algorithms, by suitably adding TC and OLA blocks at the transmitter and receiver, respectively. Using the TC-OLA-based LFM radar system, we have control over the SNR level and the spectrum spread while preserving the same Doppler shift and target time delay as the conventional LFM radar system. Furthermore, we transform LFM chirp signal into a novel TC signal that inherits LFM properties while possessing better immunity to jamming. Moreover, the proposed radar model relies on high sample rates only when needed and, therefore, does not require changing MF, MTD, and CFAR as is the case for a wideband LFM radar with the same processing gain. Detailed comparisons between the conventional LFM and the wideband LFM radars against the proposed model are also presented.

2015

The main idea of radar jamming is to minimize the (signal to interference plus Noise ratio) SINR value of the return radar echo as far as possible and also load radar screen with excessive fake target so that target detection ability of radar is voided. Here we present two jamming algorithm: Barrage and Deception jamming for surveillance radar with comparative study and also their mitigation techniques. The jamming mitigation techniques used in this text are space time adaptive processing (STAP) and Power stagger pulse with differential receiver. STAP, is based on the idea of designing a two-dimensional (space and time) filter that maximizes the output signal-to-interference noise ratio. On the other hand Power stagger pulse with Differential receiver technique is used to negate the effect of deception jamming by canceling the common jamming signal.

2011

Frequency modulated continuous wave (FMCW) radars have been widely used for measuring target range and speed. In this paper, we present a mathematical model that quantifies the system-level performance of FMCW radar systems. In FMCW radar, the target range is measured through measuring the beat frequency between the transmitted and received signal, usually by using Fast Fourier Transform (FFT). One drawback of this approach is that when the beat frequency of a target is not on the FFT grid, both the detection probability and the false alarm rate (FAR) performances are degraded. In this paper, we propose a new detector, using frequency shifts, that improves the detection probability for off the grid targets at a cost of a slight increase in FAR.

IEEE Transactions on Aerospace and Electronic Systems, 2018

A novel pulse integration has been put forward in which the radar receiver, before combining envelope detector outputs in all pulses, first clips them to a suitable level to suppress excessive energy inflicted by a jammer. Mathematical expressions for various decision metrics relevant to this scheme are derived. Using these metrics it is shown that the proposed scheme, when combined with frequency agility, yields healthy performance gain over similar detection schemes when operating against pulse jamming.

Sensors, 2022

This work studies the feasibility of using backscatter-modulated tags to introduce false information into a signal received by a frequency-modulated continuous-wave (FMCW) radar. A proof-of-concept spoofing device was designed in the 24 GHz ISM band. The spoofing device was based on an amplifier connected between two antennas, and modulation was carried out by switching the amplifier bias. The use of an amplifier allowed us to increase the level of spoofing signal compared with other modulated backscattering methods. The simulated and experimental results show that our method has the ability to generate a pair of false targets at different ranges and velocities depending on the modulation frequency of the chosen tag, since sidebands appear due to this modulation. Countermeasures to detect the spoofing attack based on changes in the slope of the frequency sweep between frames are also proposed.

Electronic Warfare Fundamentals is a student supplementary text and reference book that provides the foundation for understanding the basic concepts underlying electronic warfare (EW). This text uses a practical building-block approach to facilitate student comprehension of the essential subject matter associated with the combat applications of EW.