【正文】 W. 水面和水下 Z. 無(wú)人 飛機(jī) 駕駛車 過(guò)去的一些進(jìn)展雷達(dá) 在 20 世紀(jì)一些簡(jiǎn)單的雷達(dá)在技術(shù)方面的重大進(jìn)展有一定時(shí)間順序但沒(méi)有確切的順序，如下所述： ● 甚高頻雷達(dá)上艦部署的發(fā)展，軍事防空飛機(jī)前和二戰(zhàn)期間。 ● 發(fā)明和發(fā)展與波管的手冊(cè)行波放大管提供高功率穩(wěn)定性好。 ● 單脈沖跟蹤雷達(dá)具有良好的跟蹤精度和更好的耐高溫性能比以前跟蹤雷達(dá)有電子對(duì)抗性能。 ● 高頻超視距雷達(dá)，延長(zhǎng)了飛機(jī)和船只檢測(cè)的一個(gè)數(shù)量級(jí)范圍。 ● 逆合成孔徑雷達(dá)（ ISAR），提供了一個(gè)用于非目標(biāo)識(shí)別船舶所需的目標(biāo)圖像。 ● 多功能機(jī)載雷達(dá)的軍事相對(duì)較小，重量輕適合在一個(gè)戰(zhàn)斗機(jī)的鼻子和可以執(zhí)行不同的空對(duì)空導(dǎo)彈和飛機(jī)的功能。它本來(lái)可以更長(zhǎng)也可能包括來(lái)自本書其他各章的多個(gè)實(shí)例，但列表表明類型的進(jìn)步已為改善雷達(dá)能力的重要。 軍事雷達(dá)主要用途已經(jīng)從陸地空中，海上，防空工作。一個(gè)軍事防空雷達(dá)十分成功方法是錢已經(jīng)花的辦法來(lái)消除其巨額款項(xiàng)效果的措施。 對(duì)于使用彈道導(dǎo)彈防御雷達(dá)感興趣是因?yàn)閺椀缹?dǎo)彈的威 脅都在 50 年代末出現(xiàn)。在對(duì)彈道導(dǎo)彈的預(yù)警方法的需要導(dǎo)致了對(duì)不同類型的雷達(dá)用于執(zhí)行這種功能。 遙感環(huán)境。通常有一個(gè)精心設(shè)計(jì)前側(cè)雷達(dá)警告小型以及大型飛機(jī)在危險(xiǎn)或不利的天氣回避飛行。 空中交通管制。主要機(jī)場(chǎng)也有雷達(dá)觀測(cè)要求和安全控制飛機(jī)和機(jī)場(chǎng)地面車輛交通機(jī)場(chǎng)地面檢測(cè)設(shè)備（地面探測(cè)設(shè)備）。 其他方面應(yīng)用。探地雷達(dá)已被用來(lái)尋找埋藏公用事業(yè)線路，警察來(lái)確定 埋葬的對(duì)象定位和物品。 雷達(dá)系統(tǒng)的概念設(shè)計(jì) 目前雷達(dá)系統(tǒng)設(shè)計(jì)有各個(gè)方面。為確定各種權(quán)衡和選擇的雷達(dá)系統(tǒng)設(shè)計(jì)，從而確定最合適的理念，以滿足所需的必要的指導(dǎo)意義。一種雷達(dá)設(shè)計(jì)方法的概要是這里描述的是一種概念。在微波磁控管在第二次世界大戰(zhàn)初期發(fā)明就是一個(gè)例子。簡(jiǎn)言之它可能包括以下步驟： ● 需要或問(wèn)題描述解決。不幸地是潛在用戶之間的和雷達(dá)系統(tǒng)工程師互動(dòng)并不總是做競(jìng)爭(zhēng)采購(gòu)。在許多工程領(lǐng)域，優(yōu)化并不意味著以前是最好的，可能是無(wú)法承擔(dān)的或在規(guī)定的時(shí)間實(shí)現(xiàn)的。 ● 詳細(xì)說(shuō)明所選擇的辦法。 正如一位通過(guò)這一進(jìn)程的繼續(xù)，人們可能達(dá)成一項(xiàng) “ 死胡同 ” ，并重新開始，有時(shí)還不止一次。由于缺乏完整的資料通常大多數(shù)工程設(shè)計(jì)需要在某些時(shí)候有判斷和經(jīng)驗(yàn)的設(shè)計(jì)工程師才能取得成功。其他人可能單方面做出決定的客戶但應(yīng)小心行事。例如一個(gè)特定的天線波束可能受到跟蹤精度影響，附近的目標(biāo)分辨率，可為特殊應(yīng)用最大尺寸的天線以及對(duì)理想的雷達(dá)范圍的需要選擇雷達(dá)頻率。 IEEE 標(biāo)準(zhǔn)字典電氣和電子條款，第 4 版。卷的 AES 37 頁(yè)。 4。 6。 “ 美國(guó)和加拿大的電子表演對(duì)抗， ” 美國(guó)海軍 OPNAVINST ， 1969 年 10 月27 日。 8。 10。 數(shù)字工程圖書館 麥格勞希爾（ ） Chapter 1 An Introduction and Overview of Radar Merrill Skolnik RADAR IN BRIEF Radar is an electromagic sensor for the detection and location of reflecting objects. Its operation can be summarized as follows: ● The radar radiates electromagic 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. 21 ● 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 mon waveform radiated by a radar is a series of relatively narrow, rectangularlike pulses. An example of a waveform for a mediumrange radar that detects aircraft might be described as a short pulse one millionth of a second in duration (one microsecond)。 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 powerline poles), sea, ice, icebergs, buoys, underground features, meteors, aurora, spacecraft, and plas. In addition to measuring the range to a target as well as its angular direction, a 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 22 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. Basic Parts of a Radar. Figure is a very elementary basic block diagram showing the subsystems usually found in a radar. The transmitter, which is shown here as a power amplifier, generates a suitable waveform for the particular job the radar is to perform. It might have an average power as small as milliwatts or as large as megawatts. (The average power is a far better indication of the capability of a radar’s performance than is its peak power.) Most radars use a short pulse waveform so that a single antenna can be used on a timeshared basis for both transmitting and receiving. The function of the duplexer is to allow a single antenna to be used by protecting the sensitive receiver from burning out while the transmitter is on and by directing the received echo signal to the receiver rather than to the transmitter. The antenna is the device that allows the transmitted energy to be propagated into space and then collects the echo energy on receive. It is almost always a directive antenna, one that directs the radiated energy into a narrow beam to concentrate the power as well as to allow the determination of the direction to the target. An antenna that produces a narrow directive beam on transmit usually has a large area on receive to allow the collection of weak echo signals from the target. The antenna not only concentrates the energy on transmit and collects the echo energy on receive, but it also acts as a spatial filter to provide angle resolution and other capabilities. In radar, range is the term generally used to mean distance from the radar to the target. Range is also used here in some of its other dictionary definitions. 23 FIGURE Block diagram of a simple radar employing a power amplifier as the transmitter in the upper portion of the figure and a superheterodyne receiver in the lower portion of the figure . The receiver amplifies the weak received signal to a level where its presence can be detected. Because noise is the ultimate limitation on the ability of a radar to make a reliable detection decision and extract information about the target, care is taken to insure that the receiver produces very little noise of its own. At the microwave frequencies, where most radars are found, the noise that affects radar p