外輻射源雷達(dá)擴(kuò)展相消批處理雜波抑制算法的調(diào)制補(bǔ)償

方 亮 萬顯榮 易建新 饒?jiān)迫A 柯亨玉

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外輻射源雷達(dá)擴(kuò)展相消批處理雜波抑制算法的調(diào)制補(bǔ)償

方 亮 萬顯榮*易建新 饒?jiān)迫A 柯亨玉

(武漢大學(xué)電子信息學(xué)院 武漢 430072)

外輻射源雷達(dá)面臨嚴(yán)重的多徑雜波問題，擴(kuò)展相消批處理算法(ECA-B)是一種有效的雜波抑制算法，但該算法的分塊批處理使得相消距離元內(nèi)的雜波和目標(biāo)回波受到調(diào)制，導(dǎo)致雜波不能被完全相消而且會(huì)產(chǎn)生附加的模糊目標(biāo)。該文分析了ECA-B算法的調(diào)制機(jī)理并提出了相應(yīng)的補(bǔ)償方法，該方法首先通過載波頻偏精估計(jì)來補(bǔ)償雜波調(diào)制，然后通過合理選擇分塊數(shù)以避免目標(biāo)調(diào)制或通過估計(jì)調(diào)制距離元處每塊信號(hào)的零頻分量來補(bǔ)償目標(biāo)調(diào)制。仿真和實(shí)測數(shù)據(jù)處理結(jié)果驗(yàn)證了文中調(diào)制機(jī)理分析的正確性和所提方法的有效性，完善了該算法的性能。

外輻射源雷達(dá)；多徑雜波抑制；擴(kuò)展相消批處理算法；調(diào)制補(bǔ)償

1 引言

2 ECA-B算法原理

其中矩陣用來選擇以上構(gòu)造矩陣的后行，可表示為

則經(jīng)ECA-B算法處理的全部信號(hào)可表示為

3 調(diào)制機(jī)理分析及補(bǔ)償方法

3.1 調(diào)制機(jī)理分析

對其作FFT可得其頻譜為

其中零頻分量為

采用LS算法處理每塊監(jiān)測信號(hào)，由于該算法會(huì)抑制相消距離元內(nèi)信號(hào)的零頻分量，則處理后的每塊數(shù)據(jù)的頻譜為

其時(shí)域表達(dá)為

經(jīng)ECA-B算法處理后全部監(jiān)測信號(hào)的頻譜為

其它情況下，則

3.2 補(bǔ)償方法

為了解決ECA-B算法引入的雜波和目標(biāo)調(diào)制問題，本文根據(jù)其調(diào)制機(jī)理提出了如圖2所示的補(bǔ)償方法，具體流程如下：

圖2 補(bǔ)償方法流程圖

(4)否則將監(jiān)測信號(hào)和參考信號(hào)進(jìn)行分段相關(guān)處理獲得距離譜；

(7)對同一距離元信號(hào)作FFT獲得距離多普勒譜。

4 仿真和實(shí)測數(shù)據(jù)處理

4.1 仿真數(shù)據(jù)處理

表1雜波仿真參數(shù)

雜波直達(dá)波多徑雜波 延時(shí)(距離元)SNR(dB)06325502945624083359530129251332018115223102935

表2目標(biāo)仿真參數(shù)

目標(biāo)強(qiáng)目標(biāo)弱目標(biāo) 延時(shí)(距離元)多普勒頻移(多普勒元)SNR(dB)2008-5650-7-26

4.2 實(shí)測數(shù)據(jù)處理

圖4 實(shí)測數(shù)據(jù)處理結(jié)果

5 結(jié)論

由于ECA-B算法的分塊批處理，抑制了相消距離元內(nèi)每塊信號(hào)的零頻分量，導(dǎo)致雜波和目標(biāo)被調(diào)制，本文從理論上分析了其調(diào)制機(jī)理，并提出首先通過載波頻偏精估計(jì)來補(bǔ)償雜波調(diào)制，然后通過合理選擇分塊數(shù)以避免目標(biāo)調(diào)制或通過估計(jì)調(diào)制距離元處每塊信號(hào)的零頻分量來補(bǔ)償目標(biāo)調(diào)制。應(yīng)注意，補(bǔ)償目標(biāo)調(diào)制時(shí)所選的分塊數(shù)不宜過大，否則真實(shí)目標(biāo)的SNR被相應(yīng)消弱，不能利用其作為真實(shí)目標(biāo)的近似SNR來估計(jì)調(diào)制距離元處每塊信號(hào)的零頻分量。雖然該估計(jì)存在一定誤差，但仿真和實(shí)測數(shù)據(jù)處理結(jié)果表明所提補(bǔ)償方法仍是有效的。

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方 亮： 男，1986年生，博士生，研究方向?yàn)槔走_(dá)系統(tǒng)與信號(hào)處理.

萬顯榮： 男，1975年生，博士，教授，博士生導(dǎo)師，研究方向?yàn)闊o源雷達(dá)系統(tǒng)、高頻雷達(dá)系統(tǒng)及雷達(dá)信號(hào)處理等.

Modulation Compensation of the Batch Version of the Extensive Cancellation Algorithm for Clutter Mitigation in Passive Radar

Fang Liang Wan Xian-rong Yi Jian-xin Rao Yun-hua Ke Heng-yu

(,,430072,)

The passive radar faces a significant problem in multipath clutter, and the Batch version of the Extensive Cancellation Algorithm (ECA-B) is an efficient method for clutter mitigation. However, the clutter and target echoes, whose delays are included in the cancelled range area, are modulated due to the block batch processing in the algorithm, and it results in the clutter residues and false target emergences. The modulation mechanism of ECA-B is analyzed and the corresponding compensation method is proposed in this paper. The basic principle of the method is to compensate the clutter modulation by carrier frequency offset fine estimation and then avoid the target modulation by selecting the block number properly or compensate the target modulation by estimating zero frequency components of every block signal in the modulated range cell. The simulation and real-life data results confirm the correctness of the analysis on the modulation mechanism and the validity of the proposed method, which improves the algorithm performance.

Passive radar; Multipath clutter mitigation; Batch version of the Extensive Cancellation Algorithm (ECA-B); Modulation compensation

TN958.97

A

1009-5896(2014)01-0209-06

10.3724/SP.J.1146.2013.00384

2013-03-26收到，2013-07-18改回

國家自然科學(xué)基金(41074116, 41106156, 61271400, 60971101)和武漢大學(xué)研究生自主科研項(xiàng)目基金(274763)資助課題

萬顯榮 xrwan@whu.edu.cn