本文關(guān)鍵詞：星機(jī)雙基地SAR同步技術(shù)研究　出處：《電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 星機(jī)雙基地SAR 空間同步 時(shí)間同步 頻率/相位同步 直達(dá)波

【摘要】：本文的研究對(duì)象為星機(jī)雙基地SAR(Spaceborne/Airborne Bistatic Hybrid SAR,SA-Bi SAR)系統(tǒng),一種非對(duì)稱體制雙基地SAR系統(tǒng),其結(jié)合了星載SAR系統(tǒng)覆蓋面廣、隱蔽性強(qiáng)和機(jī)載SAR系統(tǒng)機(jī)動(dòng)靈活、分辨率高等優(yōu)點(diǎn),無論在軍事或者民用領(lǐng)域,都有較高的研究和應(yīng)用價(jià)值。以德國(guó)為代表的西方發(fā)達(dá)國(guó)家已經(jīng)展開了一系列SA-Bi SAR系統(tǒng)試驗(yàn),并取得了令人鼓舞的成果。然而,SA-Bi SAR系統(tǒng)要走向?qū)嵱没悦媾R諸多難題,同步問題便是其中之一。并且,由于非對(duì)稱性,SA-Bi SAR系統(tǒng)的同步技術(shù)與對(duì)稱體制雙基地SAR系統(tǒng)有很大差別。目前,同步問題已成為SA-Bi SAR系統(tǒng)邁向?qū)嵱没媾R的艱巨挑戰(zhàn)。針對(duì)SA-Bi SAR系統(tǒng)的同步技術(shù),本文展開了深入研究,主要工作如下:1.對(duì)SA-Bi SAR系統(tǒng)的主要技術(shù)參數(shù)進(jìn)行了分析,這些技術(shù)參數(shù)包括:空間分辨率、信噪比、成像時(shí)間、場(chǎng)景長(zhǎng)度、合成孔徑時(shí)間和測(cè)繪帶。并結(jié)合這些參數(shù),對(duì)現(xiàn)有文獻(xiàn)中提出的工作模式進(jìn)行了分析。2.針對(duì)現(xiàn)有SA-Bi SAR系統(tǒng)空間同步方法的不足,提出基于多波束接收模式的空間同步方案。分析了SA-Bi SAR系統(tǒng)空間同步的必要性,給出了所提空間同步方案的理論推導(dǎo)和實(shí)現(xiàn)步驟,通過信噪比、場(chǎng)景長(zhǎng)度和方位分辨率等性能參數(shù)與“雙寬波束模式”進(jìn)行了對(duì)比分析,驗(yàn)證了基于多波束接收的同步方法的有效性。同時(shí),對(duì)由“事前誤差”引起的成像場(chǎng)景偏移以及由“事中誤差”引起的收發(fā)波束指向偏移進(jìn)行了仿真,進(jìn)一步證明了該空間同步方案的可行性。3.詳細(xì)分析了時(shí)間同步誤差的來源、模型以及影響。借鑒現(xiàn)有理論成果,設(shè)計(jì)了一種基于直達(dá)波的SA-Bi SAR系統(tǒng)時(shí)間同步方案,給出了方案的具體實(shí)現(xiàn)步驟。為提取線性時(shí)間誤差漂移率,設(shè)計(jì)了一種高效的多普勒質(zhì)心估計(jì)算法,適用于實(shí)時(shí)處理。最后,以基于2D-PSP的RD成像算法進(jìn)行仿真,結(jié)果表明:經(jīng)時(shí)間同步誤差補(bǔ)償后的成像性能有較大改善。4.詳細(xì)分析了頻率/相位同步誤差的來源、模型以及影響。借鑒現(xiàn)有理論成果,設(shè)計(jì)了一種基于直達(dá)波的SA-Bi SAR系統(tǒng)頻率/相位同步方案,給出了方案的具體實(shí)現(xiàn)步驟。為提取每一個(gè)脈沖對(duì)應(yīng)的隨機(jī)誤差項(xiàng),設(shè)計(jì)了一種估計(jì)基線距離的方法。最后,以基于2D-PSP的RD成像算法進(jìn)行仿真,結(jié)果表明:經(jīng)頻率/相位同步誤差補(bǔ)償后的成像性能有較大改善。
[Abstract]:The research object of this paper is the bistatic SAR(Spaceborne/Airborne Bistatic Hybrid SAR-Bi SAR) system. An asymmetric bistatic SAR system combines the advantages of wide coverage, strong concealment, maneuverability and high resolution of an airborne SAR system, both in military and civilian fields. The western developed countries, represented by Germany, have carried out a series of SA-Bi SAR system tests and achieved encouraging results. SA-Bi SAR system still faces many problems to be practical, synchronization is one of them, and because of asymmetry. The synchronization technology of SA-Bi SAR system is very different from that of symmetrical bistatic SAR system. Synchronization has become a formidable challenge for SA-Bi SAR system to become practical. This paper has carried out a deep research on synchronization technology of SA-Bi SAR system. The main work is as follows: 1. The main technical parameters of SA-Bi SAR system are analyzed, including spatial resolution, signal-to-noise ratio, imaging time and scene length. Combined with these parameters, the working mode proposed in the existing literature is analyzed. 2. Aiming at the deficiency of the existing spatial synchronization method of SA-Bi SAR system. A spatial synchronization scheme based on multi-beam receiving mode is proposed, and the necessity of spatial synchronization in SA-Bi SAR system is analyzed. The theoretical derivation and implementation steps of the proposed spatial synchronization scheme are given, and the signal-to-noise ratio (SNR) of the proposed spatial synchronization scheme is given. Performance parameters such as scene length and azimuth resolution are compared with "double wide beam mode" to verify the effectiveness of the synchronization method based on multi-beam reception. The imaging scene offset caused by "prior error" and the transceiver beam pointing offset caused by "mid-incident error" are simulated. Furthermore, the feasibility of the spatial synchronization scheme is proved. 3. The source, model and influence of the time synchronization error are analyzed in detail. A time synchronization scheme for SA-Bi SAR system based on direct wave is designed, and the implementation steps are given. The linear time error drift rate is extracted. An efficient Doppler centroid estimation algorithm is designed, which is suitable for real-time processing. Finally, the Rd imaging algorithm based on 2D-PSP is simulated. The results show that the imaging performance after compensation of time synchronization error is greatly improved. 4. The source, model and influence of frequency / phase synchronization error are analyzed in detail. A frequency / phase synchronization scheme for SA-Bi SAR system based on direct wave is designed, and the implementation steps are given. The random error terms corresponding to each pulse are extracted. A method of estimating baseline distance is designed. Finally, the Rd imaging algorithm based on 2D-PSP is simulated. The results show that the imaging performance is improved greatly after the frequency / phase synchronization error is compensated.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN958

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本文編號(hào)：1432651