isar 中文意思是什麼
isar
解釋
國際審計學術研究大會-
The time - frequency curve of stern scatterer is analyzed. furthermore, high quality images are obtained by identifying the regions which are uniform in frequency. chapter 4 exposits the method of optimal time selection for ship isar imaging in detail
本章分析了船尾處特顯點的時頻分佈曲線，並選擇了時頻曲線中頻率近似不變的時間段得到艦船圖像，其成像質量有了較大的提高。 -
In order to eliminate the illegibility of boundary and large dynamic range in amplitude, this dissertation presented a preprocess method for isar profile using adaptive threshold segment
針對isar像邊緣模糊、灰度動態范圍大等特徵，對圖像預處理方法提出了改進。 -
Inverse aperture radar ( isar ) can image non - cooperative moving targets such as aircrafts, ships and celestial objects over a long distance under all weather and all day. it is of particular interest for strategic defense, anti - submarine warfare and radar astronomy
逆合成孔徑雷達（ isar ）能夠對飛機、艦艇、天體等非合作運動目標進行全天時、全天候、遠距離成像，在戰略防禦、反衛星、戰術武器以及雷達天文學中都有重要應用價值。 -
Subsequently the concrete implementation steps of them and some measurements for further improving the alignment accuracy are presented. finally, the alignment results of the isar real data achieved by these methods are shown
然後文中給出了具體實現這些方法的步驟，以及在這些方法的基礎上，進一步提高對準精度可採取的措施。 -
To improve this ability, a higher cross - range resolution is needed. an inverse synthetic aperture radar ( isar ) achieves high resolution in the cross - range dimension by taking advantage of the motion between radar and targets to synthesize the effect of a larger antenna aperture
逆合成孔徑雷達（ inversesyntheticapertureradar ，簡稱isar ）信號處理對接收到的運動目標的回波信號進行相干處理，等價成一個大口徑天線，很大程度上提高了方位向距離分辨力。 -
Therefore, the compensation in range and cross - range towards the complex movement becomes a crucial step of isar imaging
對于目標的運動補償是isar成像中的關鍵技術。 -
The united signal for the isar signal processing is called the cross - range dimension signal. the cross - range dimension signal of the target with nearly tangent motion is a linear frequency modulated signal
由推導的準切向運動目標的方位向信號的相位表示式可以看出，此信號近似為線性調頻信號。 -
Isar transmits wide bandwidth signals to obtain high range resolution. the cross - range resolution is obtained by the doppler frequency information of the target ’ s rotation
逆合成孔徑雷達通過發射大帶寬信號獲得好的距離解析度，利用目標相對于雷達的轉動產生多普勒頻率梯度來獲取好的方位向分辨力。 -
The former does not contribute to the imaging and is harmful. it influences isar imaging in two aspects : first, it causes the range misalignment of the range profiles which makes the processing in cross - range impossible
它對isar成像的影響有兩個方面：一是使相鄰的一維距離像在距離向錯開，無法進行方位向分辨。 -
Due to the short distance among the planes which fly in a group, the conventional low resolution radar can not distinguish them in both distance and azimuth ? if we use the technology of isar to resolve the difference among doppler frequency of the targets and obtain a fine resolution cross - cross image, we may separate them, but a long time of coherent processing is needed <, for the formation targets, it can be approximately divided to rigid body and nonrigid body, so for the formation targets, that can be regarded as rigid which has a relative position and an identical movement, can be approximately considered as a large target, and be compensated by translational phase with the rule of minimum entropy, but for the most those cannot accord with the approximation of rigid, being the doppler - frequency of the aim is linear changed, by the relax method with short data, increases the resolving performance of multiple target to the aim in the frequency domain, since cross - range resolution is based on the accumulative time, so it is greatly improve the resolution to formation targets by the instant cross - range image which produced by radon - wigner transformation
低分辨isan成像及干涉技術應用研究一因此直接無法分辨編隊目標的架數，我們借鑒isar的技術，通過較長時間的相干積累，在多普勒頻域上對目標進行分辨。而對于編隊目標，可分為近似剛性的多目標和非剛性的多目標，所以對于可以近似為剛體的編隊目標相對位置固定，運動方式一致，可以近似看作一個大目標，採用最小墑準則對平動相位的進行補償，但是大多數並不滿足剛體近似的編隊目標，由於目標在相干積累時間的多普勒頻率近似呈線性變化，通過對較短數據利用relax的時頻分析方法，提高了頻率域上目標分辨的性能。由於橫向解析度取塊于橫向積累時間，所以利用radnwigner變換得到瞬時的一維橫向距離像大大提高了對編隊目標的分辨，對模擬和實測數據的大量分析結果表明此方法的有效性和可行。 -
Today the city on the river isar is an economic and media metropolis with an international reputation
而今，伊薩河畔的這座城市已成為經濟和媒體發達的大都市，享有國際盛譽。 -
The method is demonstrated by using real data of airplane. the airplane isar image is evidently enhanced, and the physics - based feartures of scattering centers is gained by the method
依此框架完成了對飛機目標isar圖像有效的增強處理，提取到了反映成像目標結構特徵的點散射中心集合。 -
In practice, it ’ s very hard to find any ideal scatter points to track, so this thesis focuses on the motion compensation algorithm base on motion parameters estimation, which is used in r - d fft imaging algorithm and verified by simulation. work of this thesis contains : first analyze the signal - processing model of isar system in detail, and establish a 3 - dimensional mathematical scattering model of moving target. then some improvements are made on existing compensation algorithm, to get a higher image quality and reduce compute burden
本論文有以下幾點創新: 1 .在距離向的補償（包絡對齊）方面，採用基準相關法代替相鄰相關法或積累相關法，一定程度上解決了可能出現的包絡漂移和包絡突跳現象;根據目標運動軌跡特點，採用二次曲線擬合的方法，將包絡對齊時的局部誤差轉化為全局的誤差，以便實現較優的整體對齊效果。 -
In synthetic aperture radar ( sar ) and inverse sar ( isar ) imaging, most image algorithms are based on the model of standard scattering centers. but the scattering of targets is complexity, the standard scattering centers model cannot describe all scattering centers of target
大部分雷達二維成像演算法都是基於理想散射中心模型的，而真實目標散射的復雜性使之無法滿足理想散射中心模型的假設條件，它包含了許多非理想的散射中心。 -
The method can hold not only for isar of flying target, but also for ground moving object and sea ship after adaptive clutter suppression. + the analysis of the algorithm of low - resolution radar is made
這個演算法流程不但適用於isar空中運動目標成像，如果成像之前進行了雜波抑制也適用於地面運動目標和海面艦船目標成像。 -
B ) in isar imaging of moving targets with high speed and acceleration, the echo signal is decomposed by emd, which is used to remove the high frequency component induced by high speed or acceleration
2 、針對高速和加速度並存的機動目標，通過對回波信號的emd分解，去除由於高速和加速度產生的高頻成分，用優化后的余量進行isar成像。 -
Radar imaging of ocean - going ships is difficult to get good images because of the complicated relative motion, so time - frequency analysis is performed for ship imaging with the isar real data in chapter 3
由於雷達與艦船之間相對運動的復雜性，直接成像得到的圖像質量較差，論文第三章用時頻分析的方法，對實測數據的艦船成像進行了研究。 -
The objects of isar imaging are usually non - cooperative targets. so the motion compensation is a key technique in isar
逆合成孔徑雷達（ isar ）對非合作目標成像時，運動補償是整個成像信號處理中的一個關鍵。 -
Inverse synthetic aperture radar ( isar ) imaging of non - cooperative maneuvering multi - target is a challenging task due to its time varying orientation and the relative motion among targets
摘要非合作的機動多目標相對于雷達射線的姿態是時變的，而且目標間可能存在相對運動，給逆合成孔徑雷達（ isar ）成像造成較大困難。 -
Despite this isar signal processing method had been widely applied, it was rarely used in hf radar systems. in this paper, we probe into the application of the isar signal processing in hf radar systems elementarily
雖然以往的isar信號處理技術研究碩果累累，但是在高頻雷達領域中的應用還是較少見的，更沒有具體演算法供參考，因而本文對逆合成孔徑雷達信號處理在高頻雷達系統中的應用進行初步探索研究。
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