Abstract

The problem of radar detection of small-sized targets using the traditional methods of selection of signals embedded in background noise is considered. It is shown that for a false alarm rate of 10–5, which provides for 1–2 false alarms within the entire coverage of the modern 3D radar, the probability of detection of a small-sized target is getting unacceptably low. Repeatedly decreasing the threshold can provide an acceptable level of the detection probability at ultra-low signal-tonoise ratio (SNR) values. At the same time, decreasing the threshold will result in an unacceptable increase of the false alarm rate. A new target detection procedure using the “track before detect” method (TBD) is proposed. In the TBD procedure, the target is considered detected when two conditions are met: the signal exceeds once a definite threshold; the target is detected within a strictly defined observation area (acquisition or tracking gate). For low SNR values in the range of 3–8 dB and equal false alarm rate, the detection probability increases by 20–50 % compared to the traditional detection method. The simulation results showed a strong dependence of efficacy of the TBD algorithm on the threshold value and the decision rule. The possibility is noted of adaptive control over the threshold due to the use the detection results in the preceding scanning cycles, as well as the introduction of matrix radar surveillance not only by the target coordinates and parameters, but also by the detection threshold, decision rules, etc. Examination of these issues is the subject of further research.

Highlights

  • Detection of small-sized targets, i. e. targets with the radar cross section (RCS) in the order of 10–3...10–2 m2, using the known methods of extraction of signals embedded in noise provides poor results

  • Summarizing the previous reasoning, we shall note that, as a result of k-fold reduction of the detection threshold compared to this level for detection with the usual values of the signal-to-noise ratio (SNR) of the order of 20 dB and the probability of false alarms in one resolution bin per scan cycle F = 10-5, the true detection probability Dred = k D, and Fred = k F

  • Explaining the advantages of the track before detect” method (TBD) method based on the graph of dependence of the true detection probability (Fig. 2, b), one can note that for small values of the SNR in the range of 3–8 dB and the same false alarm rate (0.1 for this particular case), the true detection probability increases by 20–50 % in comparison with the traditional detection method

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Summary

Introduction

Detection of small-sized targets, i. e. targets with the radar cross section (RCS) in the order of 10–3...10–2 m2 (drones, fifth generation Stealth fighters, hypersonic cruise missiles), using the known methods of extraction of signals embedded in noise provides poor results. Что при условной вероятности ложной тревоги порядка 10–5, при которой обеспечиваются 1–2 ложные тревоги во всем пространстве наблюдения современной 3D радиолокационной станции (РЛС), вероятность правильного обнаружения малоразмерного объекта становится недопустимо низкой.

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