本文關(guān)鍵詞：星載多波束接收機用戶檢測技術(shù)研究　出處：《國防科學(xué)技術(shù)大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 多波束接收機 測量信號 用戶檢測 波束優(yōu)化 區(qū)域劃分

【摘要】：采用低軌衛(wèi)星與地面用戶通信,有利于控制發(fā)射成本、縮短通信距離、降低發(fā)射功率,因而在諸多領(lǐng)域獲得了廣泛應(yīng)用。用戶檢測作為星地通信的基礎(chǔ),是衛(wèi)星接收機面臨的首要問題,但較低的軌道高度使衛(wèi)星觀測信號存在明顯的遠近效應(yīng)和多普勒效應(yīng),加大了用戶檢測的難度。若采用單陣元天線,接收機難以兼顧高信噪比以及大范圍覆蓋的要求。相比之下,采用陣列天線和多波束接收技術(shù),可形成尖銳波束指向特定方位——對應(yīng)較高增益、有利于在指定方位上實現(xiàn)星地低功率通信。問題是,陣列天線增益高但波束寬度窄,若要求衛(wèi)星在覆蓋的廣大區(qū)域內(nèi),能夠與任何用戶建立有效的突發(fā)通信,天線該指向哪個方位?接收機該如何檢測用戶?上述問題可概括為論文研究的基本問題:多波束接收機中如何實現(xiàn)用戶檢測?圍繞這一基本問題,論文重點研究了如下關(guān)鍵技術(shù)問題:1、指定方位條件下的用戶檢測問題。為使用戶檢測成為現(xiàn)實問題,只能將衛(wèi)星覆蓋區(qū)域視為有限個離散點或方位,若已知某個指定方位上存在合法用戶,此時用戶檢測可理解為從實際觀測信號中提取出未知信號參數(shù)。但若用戶存在性未知,則接收機只能通過某種準(zhǔn)則來推斷觀測信號中用戶的存在性。受軌道高度、信號發(fā)射功率等條件限制,衛(wèi)星接收機要以有限的計算資源實現(xiàn)上述過程仍面臨諸多困難,這使得指定方位條件下的用戶檢測成為關(guān)鍵問題。2、限定區(qū)域條件下的波束配置問題。由于接收陣列的非理想特性,指定點或方位上的波束并非絕對尖銳,在其臨近區(qū)域內(nèi)的合法用戶也可能被檢測到,但檢測性能有所劣化。盡管這種劣化可通過加大信號觀測時間來改善,但用戶檢測代價也將隨之增大,顯然有悖問題研究的初衷。因此要在不影響檢測代價的同時解決性能劣化問題,陣列參數(shù)優(yōu)化配置則成為用戶檢測的關(guān)鍵。3、衛(wèi)星可視范圍內(nèi)的區(qū)域劃分問題。由于波束并非絕對尖銳,可將指定點連同其臨近區(qū)域看成是衛(wèi)星可視范圍內(nèi)的一個子區(qū)域,所有子區(qū)域的集合構(gòu)成了衛(wèi)星覆蓋的二維區(qū)域,接收機為每個子區(qū)域配置一個波束并進行用戶檢測。由此引出衛(wèi)星頂層設(shè)計問題:為使用戶檢測的總代價最小,需要多少個接收波束?每個波束該如何指向?這使得衛(wèi)星可視范圍的區(qū)域劃分成為關(guān)鍵。為解決上述關(guān)鍵技術(shù)問題,論文提出了一種基于置信概率的用戶檢測方案,提出了一種最小信噪比最大準(zhǔn)則的波束優(yōu)化配置方法,提出了一種結(jié)合波束數(shù)最少約束和多普勒頻移分布特性的區(qū)域劃分方法。這些技術(shù)方案或方法可對應(yīng)解決上述三個關(guān)鍵技術(shù)問題,理論分析和數(shù)值計算證明了這些技術(shù)的可行性以及有效性,可為多波束接收機用戶檢測相關(guān)載荷的研發(fā)與設(shè)計提供參考。
[Abstract]:The use of LEO satellite to communicate with the ground users helps control the launch cost, shorten the communication distance and reduce the transmitting power, so it has been widely applied in many fields. As the foundation of satellite to ground communication, user detection is the primary problem faced by satellite receivers. However, the low orbit height has obvious near far effect and Doppler effect on satellite observation signals, which increases the difficulty of user detection. If single array antenna is used, the receiver is difficult to take into account the requirements of high signal to noise ratio and wide range coverage. In contrast, the array antenna and multi beam receiving technology can form sharp beam pointing to a specific position, which corresponds to higher gain and is conducive to the realization of satellite to ground low power communication in specified directions. The problem is, but the high gain antenna array with narrow beam width, if the requirement of the satellite in a vast area covered, to establish effective emergency communications with any user, the antenna pointing position which the receiver? How to detect the user? These problems can be summarized as the research base of this problem: how to realize the multi beam receiver in multiuser detection? Around this problem, the paper focuses on the key technical problems are as follows: 1, the specified user detection range under the condition of the problem. In order to make user detection become a real problem, the satellite coverage area can be regarded as limited discrete points or azimuth. If a legitimate user is known in a specified location, then user detection can be understood as extracting unknown signal parameters from actual observation signals. But if the existence of the user is unknown, the receiver can only infer the existence of the user in the observed signal through a certain criterion. Due to the limitation of orbit height and signal transmission power, the satellite receiver still has many difficulties to achieve the above process with limited computing resources, which makes user detection under the specified location condition a key problem. 2. The problem of beam configuration under the condition of limited area. Due to the non ideal characteristics of the receiving array, the beam on the specified point or azimuth is not absolutely sharp, and the legitimate users in its adjacent area may also be detected, but the detection performance is worse. Although this deterioration can be improved by increasing the time of signal observation, the cost of user detection will also increase, which is obviously contrary to the original intention of the study. Therefore, it is necessary to solve the problem of performance degradation without affecting the detection cost, and the optimization of array parameters is the key to the user detection. 3. The problem of regionalization in the visible range of the satellite. Because the beam is not absolutely sharp, the designated point and its adjacent area can be regarded as a sub region of the satellite visibility range. The set of all sub regions constitutes a two-dimensional area covered by satellite. The receiver configuring a beam for each sub area and user detection. This leads to the problem of satellite top-level design: how many receiving beams do we need to minimize the total cost of detection, and how to point each beam, which makes the partition of the visible range of the satellite become the key. In order to solve the key technical problems mentioned above, this paper proposes a user detection scheme based on probability, proposes a minimum signal-to-noise ratio of beam optimization configuration method of maximum criterion, proposed a shift distribution region partition method combined with the least number of beam constraints and Doppler frequency. These technical solutions or methods can solve the above three key technologies. Theoretical analysis and numerical calculation prove the feasibility and effectiveness of these technologies, which can provide reference for developing and designing related load of multibeam receiver users.
【學(xué)位授予單位】：國防科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TN927.2

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1 黃志剛;星載多波束接收機用戶檢測技術(shù)研究[D];國防科學(xué)技術(shù)大學(xué);2016年

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