1950_炮瞄雷達(dá)天線自動升降機(jī)構(gòu)的設(shè)計(jì)
1950_炮瞄雷達(dá)天線自動升降機(jī)構(gòu)的設(shè)計(jì),雷達(dá),天線,自動,升降,機(jī)構(gòu),設(shè)計(jì)
黃河科技學(xué)院本 科 畢 業(yè) 設(shè) 計(jì) (論文) 任 務(wù) 書工 學(xué)院 機(jī)械 機(jī)械設(shè)計(jì)制造及其自動化 專業(yè) 08 級 1 班學(xué) 號 080105047 學(xué)生 苑兵豐 指 導(dǎo) 教 師 王 飛畢業(yè)設(shè)計(jì)(論文)題目____________________炮瞄雷達(dá)天線自動升降機(jī)構(gòu)的設(shè)計(jì)________________畢業(yè)設(shè)計(jì)(論文)工作內(nèi)容與基本要求(目標(biāo)、任務(wù)、途徑、方法,應(yīng)掌握的原始資料(數(shù)據(jù)) 、參考資料(文獻(xiàn))以及設(shè)計(jì)技術(shù)要求、注意事項(xiàng)等) (紙張不夠可加頁)一、目標(biāo)、任務(wù)及設(shè)計(jì)要求某炮瞄雷達(dá)天線重一噸,行軍時(shí)裝在車廂內(nèi),進(jìn)入戰(zhàn)斗狀態(tài)時(shí)需要把雷達(dá)天線升高 1.5米,行軍時(shí)再降下來,請?jiān)O(shè)計(jì)一個(gè)炮瞄雷達(dá)天線自動升降機(jī)構(gòu),能在 1 分鐘內(nèi)來完成天線的升或降的工作,本課題要完成的主要工作,應(yīng)用 AUTODESK CAD 設(shè)計(jì)軟件進(jìn)行設(shè)計(jì):要求:應(yīng)用所學(xué)的機(jī)械和電氣方面的知識,完成該裝置的設(shè)計(jì),選型結(jié)合現(xiàn)行主流配置進(jìn)行整體設(shè)計(jì),天線升降操作簡單、安全;設(shè)計(jì)出主要零部件。在充分查閱有關(guān)技術(shù)資料的基礎(chǔ)上應(yīng)用 AUTODESK CAD 設(shè)計(jì)軟件完成炮瞄雷達(dá)天線自動升降機(jī)構(gòu)的零件設(shè)計(jì)。通過完成方案設(shè)計(jì)、參數(shù)計(jì)算、元器件的選擇、電路圖的繪制等環(huán)節(jié),使學(xué)生綜合運(yùn)用四年來所學(xué)到的知識提高解決實(shí)際問題的能力,學(xué)會科學(xué)研究的方法、程序,培養(yǎng)嚴(yán)謹(jǐn)?shù)目茖W(xué)態(tài)度,為其即將走向工作崗位奠定良好基礎(chǔ)。二、主要設(shè)計(jì)內(nèi)容1.查閱文獻(xiàn)資料 12 種以上,外文資料不少于兩種。寫出 3000 字以上文獻(xiàn)綜述,單獨(dú)裝訂成冊。2.翻譯外文科技資料,不少于 3000 漢字,單獨(dú)裝訂成冊。3.完成開題報(bào)告,填寫開題報(bào)告表。4.完成設(shè)計(jì)方案選擇與論證,用 AUTODESK CAD 完成零件設(shè)計(jì),完成該產(chǎn)品的主要零件圖。5.繪制裝配圖, (折合后不少于 A1 圖紙 3 張,可以用計(jì)算機(jī)繪圖) 。6.編寫摘要,英中文完全對照,中文不少于 300 字。7、包含本次設(shè)計(jì)的所有內(nèi)容的光盤一張。8.編寫設(shè)計(jì)說明書,不少于 8000 字符。三、主要參考資料模擬電子線路,電子線路設(shè)計(jì),脈沖電路,機(jī)械制圖,機(jī)械工程手冊,自動控制原理,CAD 繪圖及相關(guān)資料等。四、時(shí)間安排1、第 1-3 周:對課題進(jìn)行調(diào)研, 完成文獻(xiàn)綜述、開題報(bào)告及英文資料翻譯,掌握CAD 軟件應(yīng)用功能。完成開題報(bào)告。2、第 4-5 周:閱讀資料,搞清基本原理,畫出原理圖,完成該產(chǎn)品的主要零件圖。3、第 6-8 周:通過元器件的選型設(shè)計(jì)和計(jì)算完成電路設(shè)計(jì),畫出電路圖和裝配圖。4、第 9-11 周:完成文獻(xiàn)綜述、設(shè)計(jì)說明書。5、第 12-13 周:修改論文與圖紙,準(zhǔn)備答辯。畢業(yè)設(shè)計(jì)(論文)時(shí)間: 2012 年 02 月 13 日至 2012 年 05 月 15 日計(jì) 劃 答 辯 時(shí) 間: 2012 年 05 月 19 日專業(yè)(教研室)審批意見: 審批人簽名:單位代碼 02 學(xué) 號 080105047 分 類 號 TH 密 級 畢 業(yè) 設(shè) 計(jì)文獻(xiàn)綜述院 ( 系 ) 名 稱 工 學(xué) 院專 業(yè) 名 稱 機(jī) 械 設(shè) 計(jì) 制 造 及 其 自 動 化學(xué) 生 姓 名 苑 兵 豐指 導(dǎo) 教 師 王 飛2012 年 3 月 10 日黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)綜述) 第 1 頁1.1 課題的來源、目的和研究意義1.11 課題來源本課題為自選課題1.1.2 研究目的現(xiàn)代高技術(shù)戰(zhàn)爭對雷達(dá)的越野作戰(zhàn)與戰(zhàn)場生存能力提出了越來越高的要求,以達(dá)到戰(zhàn)時(shí)快速組網(wǎng)及補(bǔ)充戰(zhàn)損的目的,高度的機(jī)動能力已經(jīng)成為現(xiàn)代軍事雷達(dá)的必備素質(zhì);因此,對于雷達(dá)設(shè)計(jì)師來說,在考慮整機(jī)電性能指標(biāo)、可靠性、可維性、可保障性、安全性、可操作性、經(jīng)濟(jì)性及加工工藝性等因素的同時(shí),還須從結(jié)構(gòu)上對其機(jī)動性作出精心構(gòu)思??偟膩碚f,雷達(dá)的高機(jī)動性須保證雷達(dá)具有這樣一種能力,即組成雷達(dá)的諸多功能環(huán)節(jié)能夠共同形成一種良好的應(yīng)變能力,在保證性能可靠的前提下,使其在遭到敵方打擊之前,能夠方便、迅速地撤收,并且轉(zhuǎn)移到新的陣地上重新進(jìn)入正常的工作狀態(tài),以達(dá)到保護(hù)自己、克敵制勝的目的;。1.1.3 研究意義雷達(dá)是一種復(fù)雜的電子機(jī)械設(shè)備,從其被研制成功之日起,就在與空中進(jìn)攻性兵器的激烈攻防對抗中不斷發(fā)展。在現(xiàn)代化戰(zhàn)爭中,地面雷達(dá)日益受到包括綜合電子干擾、低空或超低空目標(biāo)、反輻射導(dǎo)彈和隱身目標(biāo)的威脅。隱身目標(biāo)由于被雷達(dá)照射后反射回波的截面積很小,使得常規(guī)雷達(dá)難以發(fā)現(xiàn),因而可以在戰(zhàn)區(qū)上空靈活作戰(zhàn),取得明顯戰(zhàn)果。當(dāng)對方的反輻射導(dǎo)彈和隱身目標(biāo)對本方微波級雷達(dá)構(gòu)成嚴(yán)重威脅,迫使其無法開機(jī)工作時(shí),米波雷達(dá)作為警戒用雷達(dá)則因其波長較長,具備電波被吸收率低、不易散射等特點(diǎn),對通過吸收雷達(dá)電波、減少雷達(dá)角反射面、散射雷達(dá)電波來達(dá)到隱形的目標(biāo)有一定的捕捉效果,成為隱身目標(biāo)的天然克星。但是米波雷達(dá)由于工作頻率低,波束寬度窄,相應(yīng)黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)綜述) 第 2 頁的天線陣面在結(jié)構(gòu)上面積巨大,結(jié)構(gòu)比較稀疏,造成天線振子數(shù)目較多,為滿足運(yùn)輸要求不得不對天線進(jìn)行拼裝或折疊設(shè)計(jì),由于上述原因整個(gè)雷達(dá)系統(tǒng)就需要多個(gè)運(yùn)輸單元,造成機(jī)動性能一般都不高。因此迫切要求米波雷達(dá)能夠?qū)崿F(xiàn)較高的機(jī)動性能,快速轉(zhuǎn)場、越野行軍、快速架設(shè),穩(wěn)定工作,保證連續(xù)不間斷地監(jiān)視空情。1.2 國內(nèi)外研究現(xiàn)狀分析雷達(dá)一般有地面固定式和車載機(jī)動式兩種,在當(dāng)今國際形勢下,局部戰(zhàn)爭的時(shí)有爆發(fā):海灣戰(zhàn)爭、科索沃戰(zhàn)爭、阿富汗戰(zhàn)爭,現(xiàn)代戰(zhàn)爭已經(jīng)不再是人與人之間的戰(zhàn)爭,是電子化、信息化的高技術(shù)兵器之間的戰(zhàn)爭,隱身飛機(jī)、低空超低空導(dǎo)彈己不是傳統(tǒng)意義上的警戒雷達(dá)可以發(fā)現(xiàn)的,為此當(dāng)今世界各軍事強(qiáng)國都為提高自己的防空能力,為能及早發(fā)現(xiàn)來襲目標(biāo),高機(jī)動米波警戒雷達(dá)應(yīng)運(yùn)而生。米波雷達(dá)作為歷史最悠久的雷達(dá),在新的戰(zhàn)爭環(huán)境下正煥發(fā)出第二春。米波雷達(dá)由于工作頻率低,天線結(jié)構(gòu)比較稀疏,天線陣面巨大,振子數(shù)目多,運(yùn)輸單元多,裝拆、轉(zhuǎn)場比較困難,機(jī)動性一般都不高,加之米波雷達(dá)探測精度低,只能用于警戒,因此米波雷達(dá)也一度被認(rèn)為是一種性能較差的雷達(dá),這也在很大程度上限制了米波雷達(dá)的發(fā)展。但近年,隨著雷達(dá)新技術(shù)的不斷發(fā)展,米波雷達(dá)在反隱身目標(biāo)和對抗反輻射導(dǎo)彈(ARM)等方面所體現(xiàn)出的優(yōu)勢再次引起了雷達(dá)界的高度重視。目前實(shí)際應(yīng)用的隱身技術(shù),包括外形設(shè)計(jì)和吸波涂層都容易被米波雷達(dá)克制,從原理上無論如何改進(jìn)也不可能對米波雷達(dá)隱身,而且米波雷達(dá)抗干擾性極強(qiáng),兒乎能在任何電子干擾條件下使用。美、俄、法、德等國均已把米波雷達(dá)列入重新國防關(guān)鍵技術(shù)當(dāng)中,其他國家也都積極開展新體制米波雷達(dá)系統(tǒng)的研究1.2.1 俄羅斯的雷達(dá)發(fā)展情況俄羅斯的國防軍工技術(shù)十分先進(jìn),米波雷達(dá)研制方面獨(dú)樹一幟,經(jīng)驗(yàn)也相當(dāng)豐富。山于俄羅斯的國土面積遼闊,需要大批價(jià)格低廉、性能可靠的遠(yuǎn)程雷達(dá)進(jìn)行覆蓋,因此俄羅斯國防部對米波雷達(dá)的研制情有獨(dú)鐘。俄羅斯很多雷達(dá)研制單位在米波雷達(dá)研制方面具有開創(chuàng)性,俄羅斯研制了多種機(jī)動式米波三坐標(biāo)雷達(dá)系統(tǒng),如 55K6 一 3 等。黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)綜述) 第 3 頁圖 1.1 車載雷達(dá)55K6-3 雷達(dá)天線外形是一種開放式框架水平網(wǎng)絡(luò),寬約 1500Omm,上部有一個(gè)高約 2000Omm 的垂直開放式框架,主要用于對空監(jiān)視與探測和對遠(yuǎn)程空中目標(biāo)距離、方位、仰角、高度的測定,可在嚴(yán)重的干擾環(huán)境中可有效運(yùn)行。天線陣面采用拼裝形式,結(jié)構(gòu)比較復(fù)雜,需要用很多拉索穩(wěn)定,架設(shè)時(shí)一間大約需要 22 個(gè)小時(shí)左右,采用三個(gè)運(yùn)輸單元裝載。1.2.2 德國的雷達(dá)發(fā)展情況德國近期研制另一種米波圓陣列雷達(dá),由德國防務(wù)研究院高頻物理所研制的這種乍片達(dá)被稱為—MELISSA。該雷達(dá)為適應(yīng)空天一體化的作戰(zhàn)要求,采用全新的體制,全向發(fā)射,圓陣列多路接收,形成覆蓋整個(gè)方位探測空域的多波束??蓪?shí)現(xiàn)全時(shí)空探測,特別適合探測高速、高機(jī)動的目標(biāo),集搜索、引導(dǎo)和跟蹤等多種功能于一體,具有很強(qiáng)的戰(zhàn)場適應(yīng)能力,具有非常廣闊的軍事應(yīng)用前景。1.2.3 國內(nèi)的雷達(dá)發(fā)展情況我國是米波雷達(dá)的研制、生產(chǎn)和使用大國,國內(nèi)高機(jī)動雷達(dá)的設(shè)計(jì)與研制還處于起步階段,目前多是對現(xiàn)有裝備進(jìn)行改裝和調(diào)試。近年來隨著科技的發(fā)展與技術(shù)的成熟,車載米波警戒雷達(dá)也開始采用了自動調(diào)平系統(tǒng),只需要啟動電源即可完成全部架設(shè)與調(diào)平。大大縮短了展開時(shí)間,提高了調(diào)平的精度,雷黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)綜述) 第 4 頁達(dá)的可靠性、可維修性等戰(zhàn)技性能得到明顯提高,用現(xiàn)代技術(shù)改進(jìn)的米波雷達(dá)完全可以成為我軍反隱身戰(zhàn)的核心,組成一套完整而強(qiáng)有力的空中立體防御系統(tǒng),保衛(wèi)祖國領(lǐng)空。圖 1.2 某國產(chǎn)警戒雷達(dá)我國某型米波遠(yuǎn)程監(jiān)視雷達(dá),測量精度 15Om,對目標(biāo)的探測距離為330km,可在 10 秒內(nèi)處理 128 個(gè)目標(biāo),能夠較為有效地探測隱身目標(biāo),并能抗反輻射導(dǎo)彈攻擊,有可靠性高、維護(hù)性好等特點(diǎn)。圖 1.3 某機(jī)動雷達(dá)行軍狀態(tài)黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)綜述) 第 5 頁圖 1.4 某機(jī)動雷達(dá)工作狀態(tài)由國內(nèi)某電子研究所研制可迅速布防某型機(jī)動式三坐標(biāo)對空情報(bào)警戒與中遠(yuǎn)程引浮宙達(dá),采用液壓調(diào)平系統(tǒng),采用高靈敏度、高精度的水平傳感器作為水平誤差的檢測反饋元件,實(shí)現(xiàn)閉環(huán)的自動調(diào)節(jié)。適用于空軍、海軍的主戰(zhàn)警戒雷達(dá),同樣適用于地而導(dǎo)彈部隊(duì)的目標(biāo)指示雷達(dá),為地面導(dǎo)彈部隊(duì)的制導(dǎo)雷達(dá)提供大批量空中目標(biāo)的力‘位、距離、高度、敵我屬性等綜合情報(bào)。作戰(zhàn)性能優(yōu)良,高機(jī)動性、有較強(qiáng)的抗干擾及抗摧毀能力和較強(qiáng)的戰(zhàn)場生存能力。1.2.4 關(guān)鍵技術(shù)通過對國內(nèi)外幾種型號的雷達(dá)機(jī)動性的研究和分析,當(dāng)前要實(shí)現(xiàn)雷達(dá)機(jī)動性能的關(guān)鍵技術(shù)主要有以下幾個(gè)方面:1)如何實(shí)現(xiàn)雷達(dá)工作的高可靠性可靠性和機(jī)動性一樣,己經(jīng)并列成為現(xiàn)代軍用雷達(dá)和各類軍用裝備研制工作中的緊迫要求和首要指標(biāo)??煽啃允窃u估雷達(dá)的綜合作戰(zhàn)效能時(shí)的一個(gè)重要指標(biāo)。雷達(dá)不僅要求在各種復(fù)雜環(huán)境條件下可靠工作,而且還強(qiáng)調(diào)緊急機(jī)動轉(zhuǎn)移后的一次開機(jī)成功率。這就要求雷達(dá)采用標(biāo)準(zhǔn)化、模塊化設(shè)計(jì)等措施。因此如何保障機(jī)動雷達(dá)來之能戰(zhàn).戰(zhàn)之能勝的高可靠性,也是急需解決的關(guān)鍵技術(shù)之一。2)如何實(shí)現(xiàn)架設(shè)與撤收的自動化架設(shè)/撤收時(shí)間是體現(xiàn)雷達(dá)機(jī)動性能的重要指標(biāo)。為有效縮短雷達(dá)架設(shè)/撤收時(shí)間,減少人工操作,應(yīng)盡可能采用自動化手段。如何實(shí)現(xiàn)車載雷達(dá)自動升降,確保調(diào)平精度與快速的同時(shí),還要滿足可靠性與安全性,也是設(shè)計(jì)高機(jī)動雷達(dá)黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)綜述) 第 6 頁必須解決的關(guān)鍵技術(shù)之一。3 本文主要研究工作設(shè)計(jì)與研究某炮瞄雷達(dá)天線車液壓升降系統(tǒng)包括一系列關(guān)鍵技術(shù)問題,主要包括設(shè)計(jì)方案、器件選擇、結(jié)構(gòu)設(shè)計(jì)、仿真分析、理論計(jì)算等本文主要做了以下兒個(gè)方面的研究工作:1)參考國內(nèi)外設(shè)計(jì)車載雷達(dá)升降系統(tǒng)的有關(guān)資料,比較各種升降方式的優(yōu)缺點(diǎn),分析總結(jié)了國內(nèi)外已定型型號的成功研發(fā)經(jīng)驗(yàn),結(jié)合本課題的實(shí)際情況,擬定了某炮瞄雷達(dá)天線升降系統(tǒng)的總體方案。2)完成天線結(jié)構(gòu)設(shè)計(jì)。主要包括:天線座塔的結(jié)構(gòu)設(shè)計(jì)、天線塔的結(jié)構(gòu)設(shè)計(jì)、鎖定機(jī)構(gòu)的設(shè)計(jì)等。3)完成理論計(jì)算與力學(xué)仿真分析:a)液壓起豎力計(jì)算;b)車架的強(qiáng)度剛度計(jì)算;c)連桿塔強(qiáng)度校核;黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)綜述) 第 7 頁參考文獻(xiàn)[1]Merrill1Skolnik著,王軍等譯.雷達(dá)手冊(第二版)[M].北京:電子工業(yè)出版社,2003[2]黃江平.705D全自動機(jī)動式雷達(dá)天線升降裝置設(shè)計(jì).電子機(jī)械工程2001(6):91~93[3]張?jiān)鎏?機(jī)動式雷達(dá)自動架撤系統(tǒng)的結(jié)構(gòu)設(shè)計(jì).雷達(dá)科學(xué)與技術(shù),2004(12):345~348[4]錢軍.一種雷達(dá)自動舉升系統(tǒng)的設(shè)計(jì).現(xiàn)代電子,20O0(1):41-47[5]王峰,仲米生.提高液壓系統(tǒng)工作可靠性的方法.裝備,2oo6(1):22-25[6]許耀銘主編.液壓可靠性工程基礎(chǔ).哈爾濱:哈爾濱工業(yè)大學(xué)出版社,1991[7]魯建平.液壓系統(tǒng)廣義可靠性設(shè)計(jì).機(jī)床與液壓,2002(4):34-36[8]徐瀕主編.機(jī)械設(shè)計(jì)手冊(第5卷).北京:機(jī)械工業(yè)出版社,1992[9]路雨詳.液壓氣動技術(shù)手冊【M】.北京:機(jī)械工業(yè)出版社,2002[10] 陳建橋主編.材料力學(xué).華中科技大學(xué)出版社,2001[11] 鐘毅芳等主編,機(jī)械設(shè)計(jì)原理與方法.華中科技大學(xué)出版社,2002[12] 上海煤礦機(jī)械研究所編.液壓傳動設(shè)計(jì)手冊.上海人民出版社,1976[13] 唐增寶,何永然,劉安俊等主編.機(jī)械設(shè)計(jì)課程設(shè)計(jì),第二版.華中科技大學(xué)出版社,2002[14] 路甬祥主編 .液壓氣動技術(shù)手冊,機(jī)械工業(yè)出版社,2002。[15] 早稻田大學(xué)教授 加藤一郎編 .機(jī)械手圖冊,上??茖W(xué)技術(shù)出版社,1979[16] 機(jī)械工業(yè)部編.1996 機(jī)械產(chǎn)品目錄,第 7 冊.機(jī)械工業(yè)出版社, 1996[17] 全國液壓氣動標(biāo)準(zhǔn)化技術(shù)委員會編.液壓氣動標(biāo)準(zhǔn)匯編,中國標(biāo)準(zhǔn)出版社,1997[18] 何存興;液壓元件;機(jī)械工業(yè)出版社; 單位代碼 0 2 學(xué) 號 080105047 分 類 號 TH 密 級 畢 業(yè) 設(shè) 計(jì)文獻(xiàn)翻譯院 ( 系 ) 名 稱 工 學(xué) 院 機(jī) 械 系專 業(yè) 名 稱 機(jī) 械 設(shè) 計(jì) 制 造 及 其 自 動 化學(xué) 生 姓 名 苑 兵 豐 指 導(dǎo) 教 師 王 飛2012 年 03 月 10 日黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 1 頁_____________________________________________________________________________________1. RADAR IN BRIEFRadar is an electromagnetic sensor for the detection and location of reflecting objects. Its operation can be summarized as follows:● The radar radiates electromagnetic energy from an antenna to propagate in space.● Some of the radiated energy is intercepted by a reflecting object, usually called a target, located at a distance from the radar.● The energy intercepted by the target is reradiated in many directions.● Some of the reradiated (echo) energy is returned to and received by the radar antenna.● After amplification by a receiver and with the aid of proper signal processing, a decision is made at the output of the receiver as to whether or not a target echo signal is present. At that time, the target location and possibly other information about the target is acquired.A common waveform radiated by a radar is a series of relatively narrow, rectangular-like pulses. An example of a waveform for a medium-range radar that detects aircraft might be described as a short pulse one millionth of a second in duration (one microsecond); the time between pulses might be one millisecond (so that the pulse repetition frequency is one kilohertz); the peak power from the radar transmitter might be one million watts (one megawatt); and with these numbers, the average power from the transmitter is one kilowatt. An average power of one kilowatt might be less than the power of the electric lighting usually found in a “typical” classroom. We assume this example radar might operate in the middle of the microwave frequency range such as from 2.7 to 2.9 GHz, which is a typical frequency band for civilairport-surveillance radars. Its wavelength might be about 10 cm (rounding off, for simplicity). With the proper antenna such a radar might detect aircraft out to ranges of 50 to 60 nmi, more or less. The echo power received by a radar from a target can vary over a wide range of values, but we arbitrarily assume a 黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 2 頁_____________________________________________________________________________________“typical” echo signal for illustrative purposes might have a power of perhaps 10?13 watts. If the radiated power is 106 watts (one megawatt), the ratio of echo signal power from a target to the radar transmitter power in this example is 10–19, or the received echo is 190 dB less than the transmitted signal. That is quite a difference between the magnitude of the transmitted signal and a detectable received echo signal.Some radars have to detect targets at ranges as short as the distance from behind home plate to the pitcher’s mound in a baseball park (to measure the speed of a pitched ball), while other radars have to operate over distances as great as the distances to the nearest planets. Thus, a radar might be small enough to hold in the palm of one hand or large enough to occupy the space of many football fields Radar targets might be aircraft, ships, or missiles; but radar targets can also be people, birds, insects, precipitation, clear air turbulence, ionized media, land features (vegetation, mountains, roads, rivers, airfields, buildings, fences, and power-line poles), sea, ice, icebergs, buoys, underground features, meteors, aurora, spacecraft, and planets. In addition to measuring the range to a target as well as its angular direction, radar can also find the relative velocity of a target either by determining the rate of change of the range measurement with time or by extracting the radial velocity from the doppler frequency shift of the echo signal. If the location of a moving target is measured over a period of time, the track, or trajectory, of the target can be found from which the absolute velocity of the target and its direction of travel can be determined and a prediction can be made as to its future location. Properly designed radars can determine the size and shape of a target and might even be able to recognize one type or class of target from another.2 APPLICATIONS OF RADARMilitary Applications. Radar was invented in the 1930s because of the need for defense against heavy military bomber aircraft. The military need for radar has probably been its most important application and the source of most of its major developments, including those for civilian purposesThe chief use of military radar has been for air defense operating from land, sea, 黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 3 頁_____________________________________________________________________________________or air. It has not been practical to perform successful air defense without radar. In air defense, radar is used for long-range air surveillance, short-range detection of low altitude “pop-up” targets, weapon control, missile guidance, no cooperative target recognition, and battle damage assessment. The proximity fuze in many weapons is also an example of a radar. An excellent measure of the success of radar for military air defense is the large amounts of money that have been spent on methods to counter its effectiveness. These include electronic countermeasures and other aspects of electronic warfare, anti radiation missiles to home on radar signals, and low cross-section aircraft and ships. Radar is also used by the military for reconnaissance, targeting over land or sea, as well as surveillance over the sea.On the battlefield, radar is asked to perform the functions of air surveillance (including surveillance of aircraft, helicopters, missiles, and unmanned airborne vehicles), control of weapons to an air intercept, hostile weapons location (mortars, artillery, and rockets), detection of intruding personnel, and control of air traffic.The use of radar for ballistic missile defense has been of interest ever since the threat of ballistic missiles arose in the late 1950s. The longer ranges, high supersonic speeds, and the smaller target size of ballistic missiles make the problem challenging. There is no natural clutter problem in space as there is for defense against aircraft, but ballistic missiles can appear in the presence of a large number of extraneous confusion targets and other countermeasures that an attacker can launch to accompany the reentry vehicle carrying a warhead. The basic ballistic missile defense problem becomes more of a target recognition problem rather than detection and tracking. The need for warning of the approach of ballistic missiles has resulted in a number of different types of radars for performing such a function. Similarly, radars have been deployed that are capable of detecting and tracking satellites.A related task for radar that is not military is the detection and interception of drug traffic. There are several types of radars that can contribute to this need, including the long-range HF over-the-horizon radar.黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 4 頁_____________________________________________________________________________________3 MECHANICAL DESIGN CONSIDERATIONSReflector mechanical design is a detailed discipline unto itself with a multitude of factors to consider. Furthermore, designs vary significantly depending upon many factors, including platform, reflector size, environment, frequency of operation, scan/FOV, and cost constraints. Although it is not within the scope of this chapter to address mechanical design in detail, a brief survey of design factors and considerations pro-vides some useful insights.The platform, i.e., vehicle, or installation site is a significant driver for radar sensors in general, including the antenna. Platform is a generic term referring to the vehicle where the radar and antenna are installed. Typical radar platforms include pedestal (fixed site), ground vehicles, ships, airplanes, UAVs, and spacecraft/satellites. The following short section is devoted to platform impacts and some key associated design drivers. These include mass, volume (stowage/deployment), gimbals (precision mechanical positioning systems), materials, and mechanical tolerances. Finally, there is a brief discussion of environmental design considerations and radomes.The degree to which these five factors, mass, volume, stowage, deployment, and gimbaling drive the reflector design vary in accordance with the reflector system and the platform. However, mass and volume constraints generally have a significant impact on the reflector system design. Furthermore, some sort of stowage and deployment of the reflector is sometimes required, especially for larger reflectors. These considerations and constraints drive the choices of materials, structural designs, passive and active mechanisms, etc. It is beyond the scope of this chapter to address this topic in detail. However, it’s useful to show a couple examples for illustration.Consider, first, a ground-based dual-reflector design with a 9-meter main reflector aperture. This reflector, shown in Figure 12.37, is used for an S-band meteorological radar application.48 The panelized aluminum reflector is mechanically scanned via use of a gimbal (not shown). The feed, a dual-polarized waveguide horn, is also shown in Figure 12.37. The structural design of this large reflector was a significant task driven by the need to maintain low reflector surface distortion (less 黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 5 頁_____________________________________________________________________________________than 50 mils) with severe wind and gravity-loading forces and thermal gradients.The second example is a space-based deployable reflector. The mesh reflector, shown in both stowed and deployed configurations in Figure 12.38, is an offset reflector with a 12.25 meter circular projected aperture. This L-band design, developed by Northrop-Grumman Space Technologies Astro Aerospace group, has been successfully launched and deployed and is currently in use on several communication satellites. A total of five reflectors of aperture diameters 9 meters, 12 meters, and 12.25 meters have been flown. Studies have addressed the potential usage of this reflector technology for various space-based radar applications, including weather sensing/monitoring (NEXRAD)and planetary SAR mapping missions (lunar and Mars). Significant features of this reflector include its precise surface accuracy, high stiffness and stability, low mass, and reliable deployment. For example, for the reflector shown in Figure 12.38, an RMS surface accuracy of less than 50 mils from all error sources including in-orbit thermal gradients was achieved via prudent material choices and matching of the associated material coefficients of thermal expansion (CTEs). Pointing precision due to eclipse thermal snap has been measured in orbit at less than 0.01 degrees.4 SOME PAST ADVANCES IN RADARA brief listing of some of the major advances in technology and capability of radar in the twentieth century is given, in somewhat chronological but not exact order, as follows:● The development of VHF radar for deployment on surface, ship, and aircraft for military air defense prior to and during World War II.● The invention of the microwave magnetron and the application of waveguide technology early in WWII to obtain radars that could operate at microwave frequencies so that smaller and more mobile radars could be employed.● The more than 100 different radar models developed at the MIT Radiation 黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 6 頁_____________________________________________________________________________________Laboratory in its five years of existence during WWII that provided the foundation for microwave radar.● Marcums theory of radar detection.● The invention and development of the klystron and TWT amplifier tubes that provided high power with good stability.● The use of the doppler frequency shift to detect moving targets in the presence of much larger echoes from clutter.● The development of radars suitable for air-traffic control.● Pulse compression.● Monopulse tracking radar with good tracking accuracy and better resistance to electronic countermeasures than prior tracking radars.● Synthetic aperture radar, which provided images of the ground and what is on it.● Airborne MTI (AMTI) for long-range airborne air surveillance in the presence of clutter.● Stable components and subsystems and ultralow sidelobe antennas that allowed high-PRF pulse doppler radar (AWACS) with large rejection of unwanted clutter.● HF over-the-horizon radar that extended the range of detection of aircraft and ships by an order of magnitude.● Digital processing, which has had a very major effect on improving radar capabili-ties ever since the early 1970s.● Automatic detection and tracking for surveillance radars.● Serial production of electronically scanned phased array radars.● Inverse synthetic aperture radar (ISAR) that provided an image of a target as needed for noncooperative target recognition of ships.● Doppler weather radar.● Space radars suitable for the observation of planets such as Venus.● Accurate computer calculation of the radar cross section of complex targets.黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 7 頁_____________________________________________________________________________________● Multifunction airborne military radar that are relatively small and lightweight that fit in the nose of a fighter aircraft and can perform a large number of different air-to-air and air-to-ground functions.It is always a matter of opinion what the major advances in radar have been. Others might have a different list. Not every major radar accomplishment has been included in this listing. It could have been much longer and could have included multiple examples from each of the other chapters in this book, but this listing is sufficient to indicate the type of advances that have been important for improved radar capabilities.黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 8 頁_____________________________________________________________________________________1 雷達(dá)簡介雷達(dá)是一種電磁傳感器,用來對反射性物體檢測和定位。其工作可歸納如下:(1)雷達(dá)通過天線輻射電磁能量,使其在空中傳播。(2) 部分輻射的能量被離雷達(dá)某個(gè)距離上的反射體(目標(biāo))截獲。(3)目標(biāo)截獲的能量重新輻射到許多方向上。(4) 一部分重新輻射的(因波)能量返回至雷達(dá)天線,并被雷達(dá)天線所接收。(5) 在被接收機(jī)放大和合適的信號處理后,在接收機(jī)的輸出端做出目標(biāo)回波信號是否存在的判決。此時(shí),目標(biāo)的位置和可能其他有關(guān)目標(biāo)的信息就得到了。雷達(dá)輻射的一種常用波形是一串窄的類似矩形的脈沖。例如,中距離雷達(dá)用來探測飛機(jī)的波形可以描述為持續(xù) 1 微秒( vs) 的短脈沖:脈沖間隔可能為 lms (因此脈沖重復(fù)頻率為 1 kHz); 雷達(dá)發(fā)射機(jī)峰值功率可能為 1 兆瓦 C1MW); 由這些數(shù)據(jù)得出發(fā)射機(jī)的平均功率為 1 千瓦 C1kW) 0 lkW 的平均功率可能比一個(gè)"典型"教室中電燈的功率要小。我們假設(shè)這部作為例子的雷達(dá)工作在微波E 頻段的中部,例如從 2.7-2.9GHz,這是民用機(jī)場監(jiān)視雷達(dá)的典型頻段。其波長約為 10cm (簡單起見取整數(shù))。使用合適的天線,這樣一部雷達(dá)可以探測到距離③50-60n mile 左右的飛機(jī)。雷達(dá)從目標(biāo)接收到的回波功率可以在很寬范圍的值上變化,但為了示范的目的,我們?nèi)我饧僭O(shè)典型的回波信號可具有1O-13W 的功率。如果輻射的功率是 106W C1 MW) ,則此例中目標(biāo)回波信號功率與雷達(dá)發(fā)射機(jī)功率的比為 10-19 ,或接收回波比發(fā)射信號低 190dB 。這是發(fā)射信號和一個(gè)可檢測的接收回波信號幅度之間巨大的差別。一些雷達(dá)需要在短到像棒球場上從本壘到投手間的距離上檢測目標(biāo)(為測量投出球的速度),而其他雷達(dá)則需要在大到至最近的行星的距離上工作。因此,雷達(dá)可能小到足夠握在手中,或大到足夠占據(jù)許多個(gè)足球場的空間。雷達(dá)目標(biāo)可能為飛機(jī)、艦船或者導(dǎo)彈:也可能為人、烏、昆蟲、降雨、晴空空氣端流、電離的媒質(zhì)、地表特征(植被、山脈、道路、河流、機(jī)場、建筑、圍墻、電線桿等)、海洋、冰層、冰山、浮標(biāo)、地下特征、流星、極光、宇宙飛船及行星。除了測量 H 標(biāo)距離和角度方向之外,雷達(dá)通過確定距離隨時(shí)間的變化率或從回波的多普勒頻移申提取徑向速度來確定目標(biāo)的相對速度。如果在一段黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 9 頁_____________________________________________________________________________________時(shí)間內(nèi)測量動目標(biāo)的位置,則可以得到目標(biāo)軌跡或航跡,從中可以判定目標(biāo)的絕對速度和運(yùn)動方向,于是可以對其未來的位置做出預(yù)測。合適設(shè)計(jì)的雷達(dá)可以判定目標(biāo)的尺寸和形狀,甚至可以識別不同類型的目標(biāo)。2 雷達(dá)應(yīng)用因?yàn)榉烙匦蛙娪棉Z炸機(jī)的需要,在 20 世紀(jì) 30 年代發(fā)明了雷達(dá)。對雷達(dá)軍事上的需要或許是雷達(dá)最重要的應(yīng)用及其主要進(jìn)展(包括民用雷達(dá)的進(jìn)展)的來源。軍用雷達(dá)的主要用途曾是地面、海面和機(jī)載空中防御。離開雷達(dá),實(shí)施成功的空中防御是不切實(shí)際的。在空中防御中,雷達(dá)用來進(jìn)行遠(yuǎn)程監(jiān)視、低海拔"彈出"目標(biāo)的短距探測、武器控制、導(dǎo)彈制導(dǎo)、非合作目標(biāo)識別和戰(zhàn)斗損傷評估。許多武器中的近炸引信也是雷達(dá)的一個(gè)例子。對軍用防空雷達(dá)成功的一個(gè)極好度量是在反抗其有效性的方法上花費(fèi)的大量金錢。這包括電子對抗措施和其他方面的電子戰(zhàn)、尋的雷達(dá)信號的反輻射導(dǎo)彈及低截面積飛機(jī)和艦船。雷達(dá)在軍事上也用在對地面、海面的偵察及海洋監(jiān)視中。在戰(zhàn)場上,要求雷達(dá)具有執(zhí)行空中監(jiān)視(包括對飛機(jī)、直升機(jī)、導(dǎo)彈和無人機(jī)的監(jiān)視)、空中攔截武器控制、敵方武器定位(迫擊炮、火炮和火箭)、入侵人員檢測和空中交通管制等任務(wù)的功能。3 機(jī)械設(shè)計(jì)方面的考慮反射面天線的機(jī)械設(shè)計(jì)是一門精細(xì)的學(xué)科,要考慮很多因素。依據(jù)諸如平臺、天線尺寸、工作環(huán)境、工作頻率、掃描 IFOV 和成本等多種因素有多種不同的設(shè)計(jì)。限于篇幅,本節(jié)不對機(jī)械設(shè)計(jì)詳細(xì)敘述,僅對設(shè)計(jì)須考慮的因素做一概括,提供有用的深入了解。黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 10 頁_____________________________________________________________________________________載車或安裝場地等平臺通常是包括天線在內(nèi)的雷達(dá)傳感器的重要承載部件。平臺是載有雷達(dá)和天線的運(yùn)輸工具的統(tǒng)稱。典型的雷達(dá)平臺包括基座(固定站點(diǎn))、地面汽車、艦船、飛機(jī)、無人駕駛飛行器、太空船或衛(wèi)星等。下面一小段說明平臺的影響和確定設(shè)計(jì)的關(guān)鍵因素。這些因素包括平臺的重量、體積(折疊/展開)、精密機(jī)械指向系統(tǒng)、材料、機(jī)械公差等。最后,簡要討論了關(guān)于環(huán)境的設(shè)計(jì)上的考慮和天線罩。對于不同的反射面天線系統(tǒng)和安裝平臺,質(zhì)量、體積、折疊、展開和精密機(jī)械指向系統(tǒng)等五個(gè)因素對反射面天線設(shè)計(jì)的影響程度各不相同,必須靈活設(shè)計(jì)。但設(shè)計(jì)反射面天線系統(tǒng)時(shí),質(zhì)量和體積通常是主要影響因素。此外,有時(shí)還需要考慮折疊和展開,特別是大型反射面。這些要求和約束影響到材料的選擇、結(jié)構(gòu)形式設(shè)計(jì)、機(jī)械自動控制或手動控制等。詳細(xì)論述這些專題已經(jīng)超出了本章的范疇。然而,舉兩個(gè)例子說明還是很有益的。第一個(gè)例子是主反射面孔徑為 9m 的地基雙反射面天線,如圖 12 .3 7 所示。該反射面天線用于 S 頻段的氣象雷達(dá) I4810 鋁板鑲嵌制成的反射面夭線通過精密指向系統(tǒng)(圖中看不到)的轉(zhuǎn)動進(jìn)行機(jī)械掃描。圖 12 .3 7 中顯示了雙極化波導(dǎo)喇叭饋源。對于這樣大型的反射面天線,在大風(fēng)載、重力及熱量梯度的情況 1'",反射面天線要保持較低的表面變形(小于 50 密耳)的結(jié)構(gòu)設(shè)計(jì)是一項(xiàng)非常重要的工作。第二個(gè)例子是空間可展開反射面天線。該反射面天線系網(wǎng)狀,偏置饋電,圓投影孔徑直徑為 12.2 5m,折疊和展開兩種狀態(tài)如圖 12.3 8 所示[49] 。它是 North-Grumman 空間技術(shù)航天研發(fā)小組研制的 L 波段天線,己經(jīng)成功發(fā)射并展開,目前正用于多顆通信衛(wèi)星[50] 。共有五部天線在空中運(yùn)行,孔徑為 9m、 12m 和 12.25m。對于各種星載雷達(dá),包括氣象測量/監(jiān)視雷達(dá)(NEXRAD) [51] 和行星 SAR 成像雷達(dá)系統(tǒng)(探月和火星),人們對這種反射面天線的應(yīng)用潛力進(jìn)行了大量研究。這類反射面天線的重要特點(diǎn)是高表面精度、高強(qiáng)度、高穩(wěn)定性、輕質(zhì)量及可靠的展開性。例如,對于圖 12 .3 8 所示的反射面天線,在考慮所有誤差源條件下,包括軌道上的熱梯度[通過謹(jǐn)慎選擇材料及正常材料的熱膨脹系數(shù) (CTE)] 匹配,反射面表面的均方根誤差小于 50 密耳。經(jīng)過在軌測量,由于日照熱劇變引起的指向偏差小于 0.01 0 。黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 11 頁_____________________________________________________________________________________4 雷達(dá)過去的一些進(jìn)展下面簡單列出了雷達(dá)技術(shù)和性能在 20 世紀(jì)中一些主要的進(jìn)展,按不很精確的年代順序排列,如下所示:(1)第二次世界大戰(zhàn)之前和第二次世界大戰(zhàn)期間,開發(fā)為防空部署在地面、艦船和軍用飛機(jī)上的 VHF 雷達(dá)。(2) 第二次世界大戰(zhàn)早期微波磁控管的發(fā)明和波導(dǎo)技術(shù)的應(yīng)用,以獲得能在微波頻段工作的雷達(dá),從而可使用更小和機(jī)動性更強(qiáng)的雷達(dá)。(3 )MIT 輻射實(shí)驗(yàn)室在第二次世界大戰(zhàn)期間存在的五年中開發(fā)了超過 100 種不同的雷達(dá)型號,為微波雷達(dá)奠定了基礎(chǔ)。(4) Marcum 的雷達(dá)檢測理論。(5) 速調(diào)管和行波管放大器的發(fā)明和發(fā)展,提供了穩(wěn)定性好的大功率源。(6) 使用多普勒頻移來檢測淹沒于雜波中的移動目標(biāo)。(7)適于空中交通管制的雷達(dá)的開發(fā)。(8) 脈沖壓縮。(9) 單脈沖跟蹤雷達(dá)有高的跟蹤精度,以及比以前的跟蹤雷達(dá)對電子對抗措施有更好的抵御能力。(1 0) 合成孔徑雷達(dá),對地面場景和地面上的物體成像。(1 1) 機(jī)載動目標(biāo)顯示 (AMTI) ,用于在有雜波情況下遠(yuǎn)程機(jī)載空中監(jiān)視。(12) 穩(wěn)定的元件、子系統(tǒng)和超低副瓣天線,使可大量抑制無用雜波的高 P盯脈沖多普勒雷達(dá) (AWACS) 成為可能。( 13) 高頻超視距雷達(dá),把飛機(jī)和艦船的探測距離擴(kuò)大了一個(gè)數(shù)量級。(14) 數(shù)字處理,從 20 世紀(jì) 70 年代早期對雷達(dá)性能的改善有重大影響。(1 5) 監(jiān)視雷達(dá)的自動檢測和跟蹤。(16) 電掃描相控陣?yán)走_(dá)的批量生產(chǎn)。(1 7) 逆合成孔徑雷達(dá) CISAR) ,提供目標(biāo)成像,如對艦船等非合作目標(biāo)識別需要的圖像。(1 8) 多普勒氣象雷達(dá)。黃河科技學(xué)院畢業(yè)設(shè)計(jì)(文獻(xiàn)翻譯) 第 12 頁_____________________________________________________________________________________(19) 太空雷達(dá),適于對如金星等行星進(jìn)行觀測。(20) 計(jì)算機(jī)對復(fù)雜目標(biāo)雷達(dá)截面積的精確計(jì)算。(2 1)多功能機(jī)載軍用雷達(dá),體積和質(zhì)量相對小,適于安裝在戰(zhàn)斗機(jī)前端,具有執(zhí)行大量不同的雪一空和空地任務(wù)的功能。以上是對雷達(dá)過去一些主要發(fā)展的一點(diǎn)觀點(diǎn)。其他人或許有不同的看法。并非每種重大的雷達(dá)成就都包括在內(nèi)。如果包括本書其他章節(jié)的內(nèi)容,這個(gè)列表可能會更長并包含更多的例子。但是這個(gè)列表己足以顯示出對雷達(dá)性能改進(jìn)很重要的進(jìn)展類型。
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