scholarly journals Design and Implementation of an Enhanced Matched Filter for Sidelobe Reduction of Pulsed Linear Frequency Modulation Radar

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3835
Author(s):  
Ahmed Azouz ◽  
Ashraf Abosekeen ◽  
Sameh Nassar ◽  
Mohamed Hanafy
Keyword(s):  
Cross Sections ◽  
Software Defined Radio ◽  
Pulse Compression ◽  
Matched Filter ◽  
Linear Frequency ◽  
Radar Cross Sections ◽  
Operational Characteristics ◽  
Computational Speed ◽  
Iteration Methods ◽  
The Mathematical Model

Pulse compression techniques are commonly used in linear frequency modulated (LFM) waveforms to improve the signal-to-noise ratios (SNRs) and range resolutions of pulsed radars, whose detection capabilities are affected by the sidelobes. In this study, a sidelobe reduction filter (SRF) was designed and implemented using software defined radio (SDR). An enhanced matched filter (EMF) that combines a matched filter (MF) and an SRF is proposed and was implemented. In contrast to the current commonly used approaches, the mathematical model of the SRF frequency response is extracted without depending on any iteration methods or adaptive techniques, which results in increased efficiency and computational speed for the developed model. The performance of the proposed EMF was verified through the measurement of four metrics, including the peak sidelobe ratio (PSLR), the impulse response width (IRW), the mainlobe loss ratio (MLR), and the receiver operational characteristics (ROCs) at different SNRs. The ambiguity function was then used to characterize the Doppler effect on the designed EMF. In addition, the detection of single and multiple targets using the proposed EMF was performed, and the results showed that it overcame the masking problem due to its effective reduction of the sidelobes. Hence, the practical application of the EMF matches the performance analysis. Moreover, when implementing the EMF proposed in this paper, it outperformed the common MF, especially when detecting targets moving at low speeds and having small radar cross-sections (RCS), even under severe masking conditions.

scholarly journals New Side Lobe Cancellation Method of Linear Frequency Modulated Radar Signals

2020 ◽  
Vol 9 (4) ◽  
pp. 1275-1279
Keyword(s):  
Pulse Compression ◽  
Matched Filter ◽  
Roc Curves ◽  
Side Lobe ◽  
Radar Detection ◽  
Operating Characteristics ◽  
Detection Capability ◽  
Linear Frequency ◽  
Optimum Filter ◽  
Long Pulse

Pulse Compression (PC) technique has many advantages in signal processing of radar systems which enhances the radar performance. For a long pulse, the range detection capability can be increased with PC while maintain the advantage of resolution in range for uncompressed pulse. There are many PC techniques such as Binary and Linear Frequency Modulation (LFM) Codes, which can be utilize in radar. The radar detection performance is affected by unwanted signals, which called side lobes that may mask the weaker useful signals, which are present near to strong signals. Pulse compression that uses LFM code is discussed and contrasted with matched filter keep tracked of Hamming windowing filter technique to eliminate the level effect of side lobes. In the present paper, a proposed optimum filter is introduced to enhance both the radar detection capability and resolution in range. The proposed optimum filter representation is evaluated and compared with the classical matched filter response associated with Hamming windowing filter according to the representation of radar detection through Receiver Operating Characteristics (ROC) curves and resolution performance.

The Effect of Pulse Compression Chirp Parameters on Profilometry Information and Resolution

2018 ◽  
Author(s):  
Zuwen Sun ◽  
Natalie Baddour
Keyword(s):  
Pulse Compression ◽  
Imaging System ◽  
Matched Filter ◽  
Signal To Noise Ratio ◽  
Imaging Systems ◽  
Center Frequency ◽  
Matched Filtering ◽  
Linear Frequency ◽  
Recent Developments ◽  
Correlation Process

Recent developments in imaging systems have seen the implementation of a radar matched-filtering approach. The goal of the imaging system is to obtain information about an unknown object embedded in the system, by controlling the parameters of the input and measuring the response to the known input. The main merit of using matched filtering in imaging systems is the improvement of Signal to Noise Ratio (SNR). However, the correlation process used in matched filtering may result in a loss of resolution. One way to compensate for lost resolution is via pulse compression. Linear frequency modulated sinusoidal waveforms (chirps) have the property of pulse compression after correlation. Hence, both SNR and resolution can be enhanced by matched-filtering and pulse compression with a chirp. However, the theory behind the effect of chirp parameters on resolution is still not clear. In this paper, a one-dimensional theory of matched-filter imaging with a pulse compressed linear frequency modulated sinusoidal chirp is developed. The effect of the chirp parameters on the corresponding signal is investigated, and guidelines for choosing the chirp parameters for resolution considerations are given based on the developed theory and simulations. The results showed that by manipulating the center frequency, bandwidth, and duration of the chirp, the resolution can be easily enhanced.

Variational estimation of radar cross-sections

1990 ◽  
Vol 137 (4) ◽  
pp. 237 ◽  
Author(s):  
D.A. Edwards ◽  
R.A. McCulloch ◽  
W.T. Shaw
Keyword(s):  
Cross Sections ◽  
Radar Cross Sections

scholarly journals SIMULATION MODELING OF THE INTERFERENCE IMMUNITY OF THE RADARS OPERATING WITH COMPRESSED SIGNAL

2020 ◽  
Vol 8 (12) ◽  
pp. 799-804
Author(s):  
Sevdalin Ivanov Spassov ◽  
Keyword(s):  
Simulation Modeling ◽  
Pulse Compression ◽  
Matched Filter ◽  
Chirp Signal ◽  
Interference Immunity ◽  
Matched Filters ◽  
Matlab Software ◽  
Interference Signals

The immunity to the interference of a radar operating with a pulse compression signal is an important feature. The matched filter is one of the elements of the radar, providing resistance to interference. A model of a matched filter to chirp signal has synthesized using the Simulink tool of the Matlab software. Two types of interference signals have fed to the matched filter input, and the output signals are measured. The matched filters degree of suppression against these two interference signals has been assessed. Inferences about the interference immunity of the radars operating with compressed signals have been made.

scholarly journals Optimization of two-stage NLFM signal using Heuristic approach

2020 ◽  
Vol 13 (44) ◽  
pp. 4465-4473
Author(s):  
Chandu Kavitha ◽  
Keyword(s):  
Optimization Algorithm ◽  
Frequency Modulation ◽  
Pulse Compression ◽  
Piecewise Linear ◽  
Side Lobe ◽  
Linear Frequency Modulation ◽  
Main Lobe ◽  
Design And Optimization ◽  
Linear Frequency ◽  
Scripting Language

Background/Objectives: The design of appropriate Non-Linear Frequency Modulation (NLFM) signals continues to be the focus of research in radar pulse compression theory for sidelobe reduction. This study focuses on a heuristic design and optimization algorithm to optimize the side lobe values of the NLFM signal designed using two-piece wise linear frequency modulation (LFM) functions. Methods: 1) Heuristic search identifies the optimum B1, T1, and B2, T2, which yield the lowest sidelobe value of the designed function.2) Compute all the side lobe values of the designed NLFM signal using an algorithm developed in Python scripting language. To plot a complete contour map for all the calculated side lobe values, which helps identify the associated variations in the range of side lobe values. Finally, optimize the side lobe values keeping the main lobe width and time-bandwidth (BT) product unchanged by designing a dynamic optimization algorithm. Findings: The algorithm developed considered all side lobe levels after the main lobe for optimization. The focus is mainly on the peak sidelobe ratio (PSLR) value without affecting the other parameters. The results demonstrate that the achieved side lobes exhibit their desired levels. Novelty: The method is useful in all types of hardware associated with weather radar applications to military solutions. The technique can be extended to other multistage signals consisting of piecewise linear Segments. Keywords: Contour; LFM; NLFM; optimization; PSLR

scholarly journals A reconfigurable software defined ultra-wideband impulse radio transceiver

2010 ◽  
Vol 8 ◽  
pp. 67-73 ◽  
Author(s):  
M. D. Blech ◽  
A. T. Ott ◽  
P. Neumeier ◽  
M. Möller ◽  
T. F. Eibert
Keyword(s):  
Software Defined Radio ◽  
Matched Filter ◽  
Digital Signal ◽  
Impulse Radio ◽  
Ultra Wideband ◽  
Modulation Scheme ◽  
Digital To Analog Converter ◽  
Shift Keying ◽  
Reconfigurable Software ◽  
Radio Transceiver

Abstract. An ultra-wideband (UWB) software defined radio (SDR) implementation is presented. The developed impulse radio (IR) transceiver employs first order bandpass (BP) sampling at a conversion frequency which is four times the channel bandwidth. The subsampling architecture directly provides the RF signal avoiding any non-ideal mixer stages and reduces the requirements of digital signal processing implemented in a field programmable gate array (FPGA). The transmitter consists basically of a multi-Nyquist digital to analog converter (DAC), whereas the implemented matched filter (MF) receiver prototype employs a standard digitizing oscilloscope. This design can be adaptively reconfigured in terms of modulation, data rate, and channel equalization. The reconfigurable design is used for an extensive performance analysis of the quadrature phase shift keying (QPSK) modulation scheme investigating the influence of different antennas, amplifiers, narrowband interferers as well as different equalizer lengths. Even for distances up to 7 m in a multipath environment robust communication was achieved.

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