短相干積累條件下天波超視距雷達(dá)的艦船檢測
The Ship Detection of Sky Wave over-the-Horizon Radar with Short Coherent Integration Time
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摘要: 天波超視距雷達(dá)(OTHR)的觀測范圍非常廣，實(shí)戰(zhàn)中經(jīng)常要求在短相干積累條件下檢測出艦船目標(biāo)。然而短相干積累時(shí)間帶來的低多普勒分辨率很難從強(qiáng)大的海雜波中區(qū)分出艦船。為了解決這一問題?？梢圆捎煤ｋs波循環(huán)對消法，這就要求對雜波參數(shù)進(jìn)行精確估計(jì)。傳統(tǒng)方法直接利用Fourier譜中的最大幅度估計(jì)雜波參數(shù)，估計(jì)精度不高從而導(dǎo)致對消性能不太理想。該文提出了一種新的基于FFT相位分析的雜波對消法。該方法與傳統(tǒng)的雜波對消相比，有效提高了參數(shù)估計(jì)精度，減小了剩余雜波強(qiáng)度和擴(kuò)散程度，有利于艦船目標(biāo)的峰值顯露和從剩余雜波中區(qū)分出艦船。以上分析和比較得到了實(shí)測數(shù)據(jù)的檢驗(yàn)。
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關(guān)鍵詞:
- 天波超視距雷達(dá); 艦船檢測; 海雜波循環(huán)對消
Abstract: Since the surveillance area of sky wave Over-The-Horizon Radar (OTHR) is very vast, realizing the ship detection with short coherent integration time (GIT) is an operational requirement for OTHR. However, short CIT and the resulting low Doppler resolution cannot separate the ship target from the close powerful ocean clutter. To resolve this problem, clutter cancellation algorithm can be adopted but it requires accurate estimation for clutter parameters, The conventional cancellation method only uses the maximal amplitude of Fourier transform to estimate the clutter parameters, which may not get satisfied estimation and cause imperfect clutter cancellation. In this paper, the phase information of Fourier transform is combined to provide more accurate estimation of clutter parameters. As the result, the power and spreading of clutter residue are reduced which is helpful for the ship visibility and identification. The above analysis and comparison have been demonstrated by real data. -
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