Enhanced range resolution: comparison with the matched filter

Author(s):  
Krasin Georgiev Georgiev ◽  
Alessio Balleri Balleri ◽  
Andy Stove Stove ◽  
Marc W. Holderied Holderied

Matched filtering is broadly used in various radar applications and communication fields whose output indicates some range sidelobes which may mask some stronger targets. This problem can be overcome by using mismatched filter after the matched filter which increases the performance that is in terms of peak sidelobe ratio. The proposed algorithm is suitable to obtain superior performancein range resolution and detection range simultaneously. The characteristics of chaotic codes such as auto-correlation and cross-correlation are same as random codes. So the input is considered as binary and ternary chaotic sequence which is undergone matched filtering process which is then undergo mismatched filter for further reduction in the sidelobe levels. The design of mismatched filter is adapted with cuckoo search algorithm that uses Lévydistribution. It is observed that the performance of the ternary sequence is significantly improved at the output and this method is extended to various length of ternary sequences.


2018 ◽  
Vol 7 (2.20) ◽  
pp. 219
Author(s):  
K Ravi Kumar ◽  
Prof. P. Rajesh Kumar

Range resolution in radar can be achieved by splitting the long pulse of high energy into the high bandwidth of short pulses using pulse compression technique. Frequency modulation (Linear frequency modulation (LFM)) signal is used to improve range resolution. To get better range resolution, frequency step is introduced between a train of LFM pulses known as stepped frequency pulse train (the SFPT). The SFPT suffers from grating lobes when the product of sub-pulse duration and frequency step becomes more than one. The grating lobes and sidelobes present in the vicinity of the mainlobe. It can cause the false alarm detection and hide the small targets. In this work, Multi-Objective Grey Wolf Algorithm (MOGWO) is used to set the parameters of SFPT to mitigate the grating lobes and minimize the sidelobes at the matched filter output. Trade-off solutions between sidelobes versus grating lobes and mainlobe width versus sidelobes are obtained using the Pareto front for different ranges of SFPT parameters.  


2008 ◽  
Vol 26 (8) ◽  
pp. 2303-2309 ◽  
Author(s):  
G. Wannberg ◽  
A. Westman ◽  
J. Kero ◽  
C. Szasz ◽  
A. Pellinen-Wannberg

Abstract. The EISCAT UHF system has the unique capability to determine meteor vector velocities from the head echo Doppler shifts measured at the three sites. Since even meteors spending a very short time in the common volume produce analysable events, the technique lends itself ideally to mapping the orbits of meteors arriving from arbitrary directions over most of the upper hemisphere. A radar mode optimised for this application was developed in 2001/2002. A specially selected low-sidelobe 32-bit pseudo-random binary sequence is used to binary phase shift key (BPSK) the transmitted carrier. The baud-length is 2.4 μs and the receiver bandwidth is 1.6 MHz to accommodate both the resulting modulation bandwidth and the target Doppler shift. Sampling is at 0.6 μs, corresponding to 90-m range resolution. Target range and Doppler velocity are extracted from the raw data in a multi-step matched-filter procedure. For strong (SNR>5) events the Doppler velocity standard deviation is 100–150 m/s. The effective range resolution is about 30 m, allowing very accurate time-of-flight velocity estimates. On average, Doppler and time-of-flight (TOF) velocities agree to within about one part in 103. Two or more targets simultaneously present in the beam can be resolved down to a range separation <300 m as long as their Doppler shifts differ by more than a few km/s.


2011 ◽  
Vol 143-144 ◽  
pp. 634-638 ◽  
Author(s):  
Yu Tang

Phase coded radar signal is one of the pulse-pulse modulation signal in the radar system. Based on the characteristics of matched filtering, we theoretically analyze the basic principle of the phase coded compression radar system. In the Matlab platform, we set up a simulation model which is used for matching filter, when the radar transmitting signal is Barke code signal. The simulation results show that Echo signal can obtain certain pulse compression ratio. By the matched filter, the main lobe amplitude of 13 bits Barker code signal is 22 times the rate of side-lobe. 13 bits Barker codes by the matched filter have the maximum pulse compression ratio.


2020 ◽  
Vol 2020 (16) ◽  
pp. 41-1-41-7
Author(s):  
Orit Skorka ◽  
Paul J. Kane

Many of the metrics developed for informational imaging are useful in automotive imaging, since many of the tasks – for example, object detection and identification – are similar. This work discusses sensor characterization parameters for the Ideal Observer SNR model, and elaborates on the noise power spectrum. It presents cross-correlation analysis results for matched-filter detection of a tribar pattern in sets of resolution target images that were captured with three image sensors over a range of illumination levels. Lastly, the work compares the crosscorrelation data to predictions made by the Ideal Observer Model and demonstrates good agreement between the two methods on relative evaluation of detection capabilities.


2009 ◽  
Author(s):  
Richard F. Olson ◽  
William J. Braselton ◽  
Richard D. Mohlere

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