【摘要】：單脈沖前斜SAR系統(tǒng)通過雷達平臺側(cè)向機動使得SAR工作在前斜視模式下，進而實現(xiàn)目標跟蹤，是解決復雜背景下對重要軍事戰(zhàn)略目標全天時、全天候精確跟蹤問題的一種有效手段。單脈沖前斜SAR具有以下優(yōu)點：一方面，采用二維高分辨SAR成像處理，有利于提高信雜比，并且獲取的目標圖像信息豐富，有利于提高復雜背景條件下的目標檢測與識別能力；另一方面，采用SAR+單脈沖測角處理，不僅能夠在距離、多普勒二維平面中分辨目標的各個散射點，大大降低測角閃爍誤差；而且通過單脈沖處理對SAR圖像的各個分辨單元進行方位與俯仰測角，可以獲取目標的空間位置信息，有利于提高目標的定位和跟蹤能力。本文主要針對單脈沖前斜SAR系統(tǒng)技術、角度信息提取方法、目標定位與跟蹤方法等關鍵技術開展研究。論文主要工作及創(chuàng)新成果體現(xiàn)在以下幾個方面： （1）研究了單脈沖前斜SAR系統(tǒng)技術。針對俯沖前斜SAR復雜的幾何構(gòu)型、分辨率非均勻的特點，對前斜SAR分辨特性進行了分析，提出了一種基于分辨橢圓的前斜SAR分辨率分析方法�；趶V義模糊函數(shù)的定義，推導了斜平面上能夠完備描述目標分辨特性的分辨橢圓；然后基于地距平面的成像特點，推導了地距分辨橢圓的解析表達式，獲得了地距平面目標任意方向的分辨率，尤其可以得到目標沿最差方向和最優(yōu)方向的分辨率；并在此基礎上建立了描述系統(tǒng)分辨特性的誤差敏感矩陣和誤差敏感因子，提出了一種多參數(shù)聯(lián)合約束的幾何構(gòu)型優(yōu)化設計方法，與傳統(tǒng)方法相比，能夠反映系統(tǒng)分辨性能與系統(tǒng)參數(shù)、飛行航跡之間的約束關系，為系統(tǒng)幾何構(gòu)型優(yōu)化設計提供了理論依據(jù)。 （2）研究了單脈沖前斜SAR角度提取方法。針對單脈沖SAR測角中瞬時角度測量與SAR相干積累之間的矛盾，分析了角度測量誤差與相干積累時間的關系，研究了SAR成像中的角度調(diào)制特性，建立了目標時變的角運動模型，提出一種基于最小全變差準則的單脈沖SAR角度估計方法，解決了單脈沖SAR時變角度測量的問題；接著分析了平臺姿態(tài)擾動、SAR相干積累等引入的角度測量誤差；然后針對單脈沖SAR圖像中低信噪比目標測角誤差大的問題，提出了一種基于SAR單脈沖角度測量和目標區(qū)域拓撲關系的多目標角度測量的方法，基于高信噪比的特顯點目標，采用最小二乘準則在圖像域中提取低信噪比目標的角誤差，，并通過實測數(shù)據(jù)進行了驗證，可以實現(xiàn)SAR圖像中任意像素點的跟蹤，有效提高了單脈沖前斜SAR的目標跟蹤精度。 （3）研究了單脈沖SAR目標定位與跟蹤技術。單脈沖SAR可以同時獲取目標的距離、多普勒、俯仰角、方位角四維信息，由于這四維信息是分別獨立獲取的，對目標定位時存在信息冗余問題，提出了俯沖前斜SAR條件下的多維聯(lián)合定位方法，通過建立四維信息的數(shù)學模型，提取目標的定位信息，并在此基礎上引入了目標的一階角運動參數(shù)，降低了俯沖條件下高度變化和測量誤差對目標定位精度的影響；并針對二維成像與一維前視跟蹤方法開展了研究，分析了跟蹤末段鄰近目標的混疊情況，并根據(jù)飛行軌跡對方位向分辨率的影響，研究了大前斜SAR二維像與前視跟蹤階段目標一維像之間的關系，提出了基于SAR目標幅度和單脈沖角度聯(lián)合估計的目標跟蹤方法，實現(xiàn)了末端前視目標的角度跟蹤。
[Abstract]:The single-pulse front-oblique SAR system makes the SAR work in the pre-strabismus mode through the lateral maneuver of the radar platform, and then the target tracking is an effective means to solve the problem of all-weather and accurate tracking under the complex background to the important military strategic target all day. The single-pulse front oblique SAR has the advantages that the two-dimensional high-resolution SAR imaging processing is adopted, the signal-to-noise ratio is improved, the acquired target image information is rich, and the target detection and identification capability under the complex background condition is improved; and on the other hand, The method not only can distinguish various scattering points of a target in a distance and a Doppler two-dimensional plane, and greatly reduces the angle-measuring flicker error by adopting the SAR + single-pulse angle-measuring process, The spatial position information of the target can be acquired, and the positioning and tracking capability of the target can be improved. In this paper, the key technologies such as single-pulse front-oblique SAR system technology, angle information extraction method, target location and tracking method are studied. The main work and innovative achievements of the paper are reflected in the following aspects: (1) The technology of single-pulse front-oblique SAR system is studied. In view of the complicated geometric configuration and non-uniform resolution of the pre-subduction oblique SAR, the resolution characteristics of the front oblique SAR are analyzed, and a resolution analysis method based on the resolution ellipse is presented. In this paper, based on the definition of generalized fuzzy function, it is deduced that the resolution ellipse of the object-resolved characteristic can be fully described on the oblique plane, and then, based on the imaging characteristics of the ground-distance plane, the analytical expression of the ground-distance-resolved ellipse is derived, and the resolution of arbitrary direction from the plane object is obtained. In this paper, the resolution of the target in the worst direction and the optimal direction can be obtained, and the error-sensitive matrix and the error-sensitive factor describing the resolution characteristics of the system are established on the basis of this, and a method for optimizing the geometric configuration of the multi-parameter joint constraint is proposed, which is compared with the traditional method. The relationship between the system resolution performance and the system parameters and the flight path can be reflected, and the theoretical basis for the optimization design of the system geometry is provided. According to. (2), the angle of the single-pulse front oblique SAR is studied. In view of the contradiction between the instantaneous angle measurement and the SAR coherent accumulation in the single pulse SAR angle measurement, the relation between the angle measurement error and the coherent accumulation time is analyzed, the angle modulation characteristic in the SAR imaging is studied, and the target time-varying angular movement is established. In this paper, a single-pulse SAR angle estimation method based on the minimum total variation criterion is proposed to solve the problem of time-varying angle measurement of single-pulse SAR, and then the introduction of the platform attitude disturbance, SAR coherent accumulation and so on is analyzed. In this paper, a method for multi-target angle measurement based on SAR single-pulse angle measurement and target area topological relation is proposed, based on the special display of the high signal-to-noise ratio, which is based on the SAR single-pulse angle measurement and the target area topological relation. The method of the invention can realize the tracking of any pixel point in the SAR image and effectively improve the target of the single-pulse front oblique SAR by using the least square criterion to extract the angular error of the low signal-to-noise ratio target in the image domain, The tracking precision is studied. (3) The target location of the single pulse SAR is studied. The single-pulse SAR can obtain the four-dimensional information of the distance, the Doppler, the pitch angle and the azimuth angle of the target at the same time, because the four-dimensional information is obtained independently, the problem of information redundancy exists when the target is positioned, and the multi-dimensional link under the condition of the pre-dive oblique SAR is proposed. The location information of the target is extracted by establishing a mathematical model of the four-dimensional information, the first-order angular motion parameter of the target is introduced, the altitude change and the measurement error of the target are reduced under the subduction condition, The influence of the precision on the accuracy is studied, the aliasing of the adjacent target in the end section is analyzed and the influence of the flight trajectory on the resolution of the azimuth is analyzed, and the one-dimensional image of the two-dimensional image of the front oblique SAR and the forward tracking stage is studied. The target tracking method based on the combination of SAR target amplitude and single pulse angle is proposed, and the end-end forward-looking target is achieved.
【學位授予單位】：北京理工大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TN957.52

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