scholarly journals Optimal Polyphase Coded Signal Design

2019 ◽  
Vol 8 (4) ◽  
pp. 9372-9376
Keyword(s):  
Cross Correlation ◽  
Recognition Performance ◽  
Pso Algorithm ◽  
Signal Design ◽  
Detection Range ◽  
Range Resolution ◽  
Signal Jamming ◽  
Global Arena ◽  
Detection And Recognition ◽  
High Range

In the war prone global arena where every target of an enemy, on and off the land to be kept on eagle’s eye watch and to deceive enemy’s counter measure technologies, there is a strong requirement for most secured signal design which domicile maximum detection range along with high range resolution, to flare them up .The efficiency of the system mainly depends on how much power the generated pulse may possess in the main lobe to that of the side lobes and how independent they are from one another. The measure of Autocorrelation and cross correlation exhibited by polyphase coded sequence is determined mathematically. Multi input and multi output possesses best potential in mitigating the effects of fading, enhancing the resolution, suppressing the signal jamming and interference, which are all very useful in improving the target detection and recognition performance of the system. Recently, most optimization researches of polyphase codes are carried out by genetic algorithm (GA), Particle swarm optimization (PSO) and simulated annealing (SA) but this technique require more parameters for optimization. In order to overcome these difficulties modified PSO algorithm is adopted in the present research to optimize the polyphase coded sequence. The obtained codes are also put for Doppler resilience by including Doppler shift in the process of generation of the codes.

scholarly journals Inferring fish orientation from broadband-acoustic echoes

2003 ◽  
Vol 60 (3) ◽  
pp. 524-531 ◽  
Author(s):  
Timothy K Stanton ◽  
D.Benjamin Reeder ◽  
J.Michael Jech
Keyword(s):  
Cross Correlation ◽  
A Priori ◽  
Orientation Angle ◽  
Normal Incidence ◽  
Design Parameters ◽  
Model Design ◽  
Frequency Range ◽  
Range Resolution ◽  
Laboratory Tank ◽  
High Range

Abstract A new method has been developed for inferring the orientation of fish through the use of broadband-acoustic signals. The method takes advantage of the high range resolution of these signals, once temporally compressed through cross-correlation. The temporal resolution of these compressed signals is inversely proportional to the bandwidth, thus the greater the bandwidth the higher the resolution. This process has been applied to broadband-chirp signals spanning the frequency range 40–95 kHz to obtain a range resolution of approximately 2 cm from the original, unprocessed resolution of about 50 cm. With such high resolution, individual scattering features along the fish have been resolved, especially for angles well off normal incidence. The overall duration of the compressed echo from live, individual alewife, as measured in a laboratory tank, is shown to increase monotonically with orientation angle relative to normal incidence. The increase is due to the greater range separation relative to the transducer between the echoes from the head and tail of the fish. The results of this study show that with a priori knowledge of the length of the fish, the orientation could be estimated from the duration of a single, compressed broadband echo. This method applies to individual, acoustically resolved fish. It has advantages over previous approaches because it derives the orientation from a single ping and it does not use a formal, mathematical scattering model. Design parameters for applications in the ocean are given for a range of conditions and fish size.

scholarly journals Precision Imaging of Frequency Stepped SAR with Frequency Domain Extracted HRRP and Fast Factorized Back Projection Algorithm

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Can-bin Yin ◽  
Da Ran
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Single Point ◽  
Projection Algorithm ◽  
Great Promise ◽  
Back Projection ◽  
Imaging Processing ◽  
Block Partition ◽  
Range Resolution ◽  
High Range

Novel frequency domain extracted method (FDEM) to obtain high range resolution profile (HRRP) for frequency stepped synthetic aperture radar (SAR) is proposed in this paper, and the mathematical principle and formulas of this new HRRP obtaining idea combined with classical fast Fourier transform (FFT), chirp z transform (CZT), and single point Fourier transform (SPFT) are deduced, analyzed, and compared in detail. Based on the HRRP data, precision imaging processing is completed using a data block partition based fast factorized back projection algorithm. Imaging validations are executed and all results proved that the FDEM has a great capability of antijamming. It is more effective than conventional time domain IFFT method (TDM) and shows a great promise in frequency stepped radar imaging and applications.

An evolutionary multiclass algorithm for automatic classification of high range resolution radar targets

2009 ◽  
Vol 16 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Leo Carro-Calvo ◽  
Sancho Salcedo-Sanz ◽  
Roberto Gil-Pita ◽  
Antonio Portilla-Figueras ◽  
Manuel Rosa-Zurera
Keyword(s):  
Automatic Classification ◽  
Range Resolution ◽  
Radar Targets ◽  
High Range Resolution Radar ◽  
High Range
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