外文翻譯--車輛檢測技術(shù)在交通管理上的應(yīng)用

1、<p>　　畢業(yè)設(shè)計(論文)外文資料翻譯</p><p>　　Vehicle Detector Technologies for Traffic Management Applications</p><p><b>　　Part 1</b></p><p>　　Lawrence A. Klein </p><p&

2、gt;　　Consultant </p><p>　　Ten different detector technologies were recently evaluated as part of the FHWA-sponsored Detection Technology for IVHS program. The two primary goals of the program were: </p>

3、;<p>　　To determine traffic parameters and their corresponding measurement accuracies for future Intelligent Transportation Systems (ITS) applications, </p><p>　　To perform laboratory and field tests

4、with above-the-road mounted, surface, and subsurface detectors to determine their performance.</p><p>　　Detectors representative of all tested technologies were found to satisfy current traffic management re

5、quirements. However, improved accuracies and new types of information, such as queue length and vehicle turning or erratic movements, may be required from detectors for future traffic management applications. The choice

6、of a detector for a specific application is, of course, dependent on many factors, including data required, accuracy, number of lanes monitored, number of detection zones per la</p><p>　　The results of this

7、evaluation project is being presented in two parts. Part 1 introduces the theory of operation and the strengths and weaknesses of the various overhead detector technologies. Part 2 will provide field evaluation data and

8、some general conclusions about detector performance and applications. Copies of the Final Report, a set of five compact disks containing the detector evaluation data, and other reports are available from the FHWA by writ

9、ing to Mr. Pete Mills at HSR-1, 6300 Geo</p><p>　　Note: The detector performance data presented in this article were obtained by Dr. Klein when he was the project’s Principal Investigator at Hughes Aircraft

10、Company. </p><p>　　INTRODUCTION</p><p>　　Maximizing the efficiency and capacity of the existing ground transportation network is made necessary by the continued increase in traffic volume and th

11、e limited construction of new highway facilities in urban, intercity, and rural areas. Smart street systems that contain traffic monitoring detectors, real-time adaptive signal control systems, and motorist communication

12、s media are being combined with freeway and highway surveillance and control systems to create smart corridors that increase th</p><p>　　Vehicle detectors are an integral part of these modern traffic control

13、 systems. The types of traffic flow data, as well as their reliability, consistency, accuracy, and precision, and the detector response time are some of the critical parameters to be evaluated when choosing a vehicle det

14、ector. These attributes become even more important as the number of detectors proliferate and the real-time control aspects of ITS put a premium on the quantity and quality of traffic flow data, as well as the </p>

15、<p>　　Current vehicle detection is based predominantly on inductive loop detectors (ILDs) installed in the roadway subsurface. When properly installed and maintained, they can provide real-time data and a historic

16、al database against which to compare and evaluate more advanced detector systems. Alternative detector technologies being developed provide direct measurement of a wider variety of traffic parameters, such as density (ve

17、hicles per mile per lane), travel time, and vehicle turning movement. The</p><p>　　Newer detectors with serial outputs currently require specific software to be written to interpret the traffic flow paramete

18、rs embedded in the data stream. Since each detector manufacturer generally uses a proprietary serial protocol, each detector with a unique protocol requires corresponding software. This increases the installation cost or

19、 the real purchase price of the detector. Furthermore, not every detector outputs data on an individual vehicle basis. While some do, others integrate the d</p><p>　　In performing the technology evaluations

20、and in analyzing the data, focus was placed on the underlying technology upon which the detectors were based [1,2]. It was not the purpose of the program to determine which specific detectors met a set of requirements, b

21、ut rather whether the sensing technology they used had merit in measuring and reporting traffic data to the accuracy needed for present and future applications. Obviously, there can be many implementations of a technolog

22、y, some of which ma</p><p>　　Not all detectors were available at all sites as shown in the footnotes to the table. A summary of the advantages and disadvantages of the detector technologies is given in Table

23、 2. Some of them are application specific, implying that a particular technology may be suitable for some but not all applications. A factor not addressed in this table is detector cost. This issue is again application s

24、pecific. For example, a higher cost detector may be appropriate for an application requiring specific </p><p>　　Table 3 shows examples of overhead detector technology compatibility with several traffic manag

25、ement applications. The assumptions shown concerning the application dictate, in part, the appropriateness of the technology. </p><p>　　THEORY OF OVERHEAD DETECTOR OPERATION</p><p>　　The followi

26、ng paragraphs give a brief explanation of the underlying operating principles for microwave, passive infrared, active infrared, ultrasonic, passive acoustic, and video image processor detectors. </p><p>　　Mi

27、crowave Radar </p><p>　　Microwave radars used in the U.S. for vehicle detection transmit energy at 10.525 GHz, a frequency allocated by the FCC for this purpose. Their output power is regulated by the FCC an

28、d certified by the manufacturer to meet FCC requirements. No further certification is required of the transportation agencies for their deployment. </p><p>　　Two types of microwave radar detectors are used i

29、n traffic management applications. The first transmits electromagnetic energy at a constant frequency. It measures the speed of vehicles within its field of view using the Doppler principle, where the difference in frequ

30、ency between the transmitted and received signals is proportional to the vehicle speed. Thus, the detection of a frequency shift denotes the passage of a vehicle. This type of detector cannot detect stopped vehicles and

31、is, therefo</p><p>　　The second type of microwave radar detector transmits a sawtooth waveform, also called a frequency-modulated continuous wave (FMCW), that varies the transmitted frequency continuously wi

32、th time. It permits stationary vehicles to be detected by measuring the range from the detector to the vehicle and also calculates vehicle speed by measuring the time it takes for the vehicle to travel between two intern

33、al markers (range bins) that represent known distances from the radar. Vehicle speed is then s</p><p>　　Passive Infrared Detectors </p><p>　　Passive infrared detectors can supply vehicle passage

34、 and presence data, but not speed. They use an energy sensitive photon detector located at the optical focal plane to measure the infrared energy emitted by objects in the detector’s field of view. Passive detectors do n

35、ot transmit energy of their own. When a vehicle enters the detection zone, it produces a change in the energy normally measured from the road surface in the absence of a vehicle. The change in energy is proportional to t

36、he abso</p><p>　　Active Infrared Detectors </p><p>　　Active infrared detectors function similarly to microwave radar detectors. The most prevalent types use a laser diode to transmit energy in t

37、he near infrared spectrum (approximately 0.9 micrometer wavelength), a portion of which is reflected back into the receiver of the detector from a vehicle in its field of view. Laser radars can supply vehicle passage, pr

38、esence, and speed information. Speed is measured by noting the time it takes a vehicle to cross two infrared beams that are scanned across </p><p>　　Ultrasonic Detectors </p><p>　　Ultrasonic veh

39、icle detectors can be designed to receive range and Doppler speed data. However, the most prevalent and low-cost ultrasonic detectors are those that measure range to provide vehicle passage and presence data only. The ul

40、trasonic Doppler detector that also measures vehicle speed is an order of magnitude more expensive than the presence detector. Ultrasonic detectors transmit sound at 25 kHz to 50 kHz (depending on the manufacturer). Thes

41、e frequencies lie above the audible region. A </p><p>　　Passive Acoustic Detectors </p><p>　　Vehicular traffic produces acoustic energy or audible sound from a variety of sources within the vehi

42、cle and from the interaction of the vehicle’s tires with the road surface. Arrays of acoustic microphones are used to pickup these sounds from a focused area within a lane on a roadway. When a vehicle passes through the

43、detection zone, the signal-processing algorithm detects an increase in sound energy and a vehicle presence signal is generated. When the vehicle leaves the detection zone, the sou</p><p>　　車輛檢測技術(shù)在交通管理上的應(yīng)用<

44、;/p><p><b>　　第1部分</b></p><p><b>　　勞倫斯·克萊因</b></p><p><b>　　顧問</b></p><p>　　10種不同的檢測技術(shù)最近為聯(lián)邦公路管理局贊助的智能車輛公路系統(tǒng)節(jié)目的一部分而被評估了。這個節(jié)目的兩個主要目標(biāo)是：

45、</p><p>　　以確定未來的智能交通系統(tǒng)（ITS）應(yīng)用的交通參數(shù)和相應(yīng)的測量精度，</p><p>　　為了執(zhí)行實驗室和現(xiàn)場測試的道路上的安裝，地表和地下檢測器，以確定它們的性能。</p><p>　　所有測試技術(shù)的代表性檢測器被發(fā)現(xiàn)滿足當(dāng)前交通管理的要求。但無論怎樣,，提高精度和新的信息類型，如隊列長度和車輛轉(zhuǎn)彎或不穩(wěn)定的運動，在未來的交通管理應(yīng)用中可能需要

46、使用檢測器。一個特定的應(yīng)用程序的檢測器的選擇，當(dāng)然，依賴于許多因素，包括所需的數(shù)據(jù)，精度，監(jiān)測車道的數(shù)量，每通道的檢測區(qū)域，檢測器采購和維護成本，供應(yīng)商的支持，并與當(dāng)前和未來的交通管理基礎(chǔ)設(shè)施的兼容性。</p><p>　　本評估節(jié)目的結(jié)果被分為兩部分。第1部分介紹了工作原理和各種檢測技術(shù)的優(yōu)勢和弱點。第二部分將提供現(xiàn)場評價數(shù)據(jù)和一些檢測器的性能和應(yīng)用的一般性結(jié)論。總結(jié)報告的副本中，包含了一組5個檢測器的評價數(shù)據(jù)

47、光盤，其他的皮特·米爾斯先生在弗吉尼亞州22101麥克萊恩的6300喬治敦派克的高鐵1號線上寫的報告可從聯(lián)邦公路管理局里得到。</p><p>　　注：在這篇文章中提出的檢測器性能數(shù)據(jù)，是克萊因博士他在休斯飛機公司作為該項目的首席研究員時獲得的。</p><p><b>　　引言</b></p><p>　　在交通量的不斷增加和有限的

48、建設(shè)新的城市，城際，農(nóng)村的公路設(shè)施，最大限度地發(fā)揮現(xiàn)有的地面交通網(wǎng)絡(luò)的效率和能力是有必要的。街道智能系統(tǒng)，包含流量監(jiān)控檢測器，實時自適應(yīng)信號控制系統(tǒng)，駕車通信媒體正在與高速公路和公路的監(jiān)測和控制系統(tǒng)相結(jié)合，以創(chuàng)建智能走廊，增加的交通運輸網(wǎng)絡(luò)的有效性。反過來，基礎(chǔ)設(shè)施的改善和新技術(shù)與通信工具和智能汽車和公共接入領(lǐng)域（如商場）的集成顯示，形成智能交通系統(tǒng)。</p><p>　　車輛檢測器是這些現(xiàn)代化的交通控制系統(tǒng)的基

49、本組成部分。當(dāng)選擇一個車輛檢測器對交通數(shù)據(jù)流，以及它們的可靠性，一致性，準(zhǔn)確性和精確度，和檢測器響應(yīng)時間等一些關(guān)鍵參數(shù)進行評估。隨著檢測器數(shù)量的激增，這些屬性變得更加重要和把流量數(shù)據(jù)的數(shù)量和質(zhì)量，以及對數(shù)據(jù)的解釋的智能交通系統(tǒng)的實時控制方面，集成到現(xiàn)有的交通控制系統(tǒng)中。</p><p>　　目前的車輛檢測器主要是安裝在地下巷道的感應(yīng)線圈檢測器（ILDS）。當(dāng)正確安裝和維護時，它們可以提供實時數(shù)據(jù)和歷史數(shù)據(jù)庫作比較

50、可以評估更先進的檢測系統(tǒng)。替代檢測技術(shù)正在開發(fā)提供一個更廣泛的交通參數(shù)，如密度（每公里每車道的車輛），旅行時間，車輛轉(zhuǎn)向運動等的直接測量。這些先進的檢測器提供更準(zhǔn)確的數(shù)據(jù)，參數(shù)不是原來的儀器投入到大面積的監(jiān)測和控制信號的路口和高速公路直接測量的，以及駕駛者的信息服務(wù)的支持。此外，許多先進的檢測系統(tǒng)可以安裝并保持不中斷交通流。一些稀少的地埋檢測器將繼續(xù)尋找在未來的應(yīng)用，例如，在審美方面的問題上主導(dǎo)或程序地方監(jiān)測和修復(fù)故障單元在日?；A(chǔ)。&

51、lt;/p><p>　　目前較新的串行輸出的檢測器需要特定的軟件，要寫入解釋嵌入在數(shù)據(jù)流中的交通流參數(shù)。由于每個檢測器制造商普遍采用了專有的串行協(xié)議，每個擁有一個獨特的協(xié)議的檢測器需要相應(yīng)的軟件。這增加了安裝成本或檢測器的實際購買價格。此外，并不是每個檢測器都輸出個別車輛的基礎(chǔ)數(shù)據(jù)。雖然有些在做，有些在整合從幾十秒鐘到幾分鐘期間該范圍內(nèi)的數(shù)據(jù)和輸出結(jié)果，生產(chǎn)參數(shù)是宏觀交通流的特點。因此，當(dāng)比較不同的檢測器輸出的時候，

52、交通管理機構(gòu)必須謹(jǐn)慎使用。</p><p>　　在執(zhí)行技術(shù)評估和分析數(shù)據(jù)時，重點是放在基于底層技術(shù)[1,2]的該檢測器上。這不是確定滿足一系列要求的具體檢測器的用途，而是在于他們是否使用傳感技術(shù)測量交通數(shù)據(jù)并報告流量數(shù)據(jù)，為現(xiàn)在和未來的應(yīng)用提供準(zhǔn)確的需要。明然，可以有許多實現(xiàn)技術(shù)的裝置，其中一些在任何時候可能比另外一些更好地被利用。因此，這種技術(shù)可能會在未來的應(yīng)用中被實現(xiàn)，但當(dāng)前的硬件或軟件的狀態(tài)可能會阻礙其目前

53、的發(fā)展。在技術(shù)評估過程中實地測試使用的檢測器，在表1中列出。</p><p>　　并非在表格的所有注腳中顯示的所有的檢測器可以使用。表2給出了檢測技術(shù)的優(yōu)點和缺點的一個總結(jié)。其中一些有著特定的用途，這意味著一個特定的技術(shù)可能適合一些，但并非所有的應(yīng)用。本表中未涉及的一個因素是檢測器的成本。這個問題也是具體的應(yīng)用。例如，較高的成本檢測器可能需要具體的數(shù)據(jù)的應(yīng)用或多個檢測區(qū)域（適用于多車道覆蓋）被歸納入更昂貴的檢測器

54、是適當(dāng)?shù)摹?lt;/p><p>　　表3顯示了以上提到的檢測技術(shù)在幾個交通管理應(yīng)用方面的兼容性的例子。假設(shè)顯示有關(guān)應(yīng)用的要求，部分的，適當(dāng)?shù)募夹g(shù)。</p><p>　　以上檢測器的操作理論</p><p>　　以下段落簡要說明了微波，被動紅外，主動紅外，超聲波，被動聲波，視頻圖像處理檢測器的基本工作原理。</p><p><b>　　微

55、波雷達</b></p><p>　　在美國使用的微波雷達車輛檢測器發(fā)射頻率為10.525 GHz ，由聯(lián)邦通訊委員為了此目的而分配頻率。它們的輸出功率由聯(lián)邦通訊委員監(jiān)管和由制造廠商認證，從而符合聯(lián)邦通訊委員的要求。沒有進一步的認證要求遵從交通部門它們的部署。</p><p>　　兩種類型的微波雷達檢測器應(yīng)用在交通管理方面。首先發(fā)送在一個恒定頻率的電磁波能量。在其檢測范圍之內(nèi)，它

56、可以采用發(fā)送和接收信號頻率與車速成比例的不同的多普勒原理來測量車輛的速度。因此，檢測到一個頻移就表示一輛車的通行。這種類型的檢測器無法檢測到停止的車輛，因此，不適合應(yīng)用到需要車輛存在的地方，如在信號燈或停車吧。</p><p>　　第二種類型的微波雷達檢測器發(fā)送一個鋸齒波，也稱為調(diào)頻連續(xù)波（FMCW） ，發(fā)射頻率隨時間不斷變化而變化。它允許在檢測器測量車輛的范圍內(nèi)檢測固定車輛并計算測量所花費的時間。它需要來往的車

57、輛作為兩個內(nèi)部標(biāo)記（范圍箱）代表距離雷達已知的距離。兩個范圍箱之間的距離也就是需要車輛行駛的距離除以所花費的時間然后簡單地計算一下就得到了車速。由于這種檢測器可以檢測到停止車輛，它有時也被稱為作為一個真實存在的微波雷達。</p><p><b>　　被動紅外檢測器</b></p><p>　　被動紅外檢測器，可以提供車輛通行和存在的數(shù)據(jù)，但是不可以測速。他們在檢測器的

58、測量范圍內(nèi)使用位于光學(xué)焦距處的光敏檢測器測量平面上的向外發(fā)散的紅外能量。被動檢測器不向外發(fā)射自己的能量。通常在沒有車輛的路面上測量時，當(dāng)車輛進入檢測區(qū)，它會產(chǎn)生的能量的變化。在能量的變化是與車輛的絕對溫度和汽車的金屬表面的發(fā)射率成正比的(發(fā)射率等于在相同的外界溫度的條件下由燃料燃燒發(fā)出的能量與完美的散熱器散發(fā)出的能量實際上的比值)。當(dāng)在大氣中有水汽，雨，雪或霧時，到達檢測器的能量會減少。當(dāng)這種類型的檢測器應(yīng)用在典型的大約20英尺（6.1

59、米）距離的交通監(jiān)控中時，不會因為這些大氣成分而可能產(chǎn)生顯著的性能減弱。</p><p><b>　　主動紅外檢測器</b></p><p>　　主動紅外檢測器的功能類似于微波雷達檢測器。最普遍的類型就是使用激光二極管，在近紅外光譜（波長約0.9微米）上發(fā)射，其中一部分能量被在其檢測范圍內(nèi)的車輛反射回接收檢測器。激光雷達可以提供車輛的通行，存在和速度等信息。速度是衡量注

60、意到車輛跨越兩個紅外線光束，整個路面掃描已知的距離所花費的時間。測量速度要注意的是在已知的距離上需要掃描一個路面上的車輛通過兩個紅外光束的時間。一些激光雷達檢測器也有能力通過測量來分類車輛，并確定它們的資料。其他類型的主動紅外檢測器使用發(fā)光二極管（LED）作為信號源。</p><p><b>　　超聲波檢測器</b></p><p>　　超聲波車輛檢測器可以接收一定范

61、圍和多普勒速度數(shù)據(jù)。然而，最普遍的和低成本的超聲波檢測器只提供測量范圍內(nèi)的車輛通行和存在的數(shù)據(jù)。超聲多普勒檢測器，還可以測量車速，它是一個比現(xiàn)有的檢測器更昂貴一個等級的檢測器。超聲波檢測器能發(fā)射25 kHz至50 kHz （取決于制造商）的聲波。這些頻率在以上發(fā)聲地區(qū)都有。一部分發(fā)射的能量經(jīng)過道路或車輛的表面反射后被儀器的接收部分接收和處理后驗證了車輛通行和存在。一個典型的超聲波檢測器以脈沖的形式發(fā)射超聲波能量。檢測器的脈沖信號從離開到

62、返回到檢測器測量的往返時間是與反射的表面到檢測器的距離成正比關(guān)系的。檢測門的設(shè)置的目的是確定路面的范圍和抑制從道路本身反射回的檢測信號。當(dāng)車輛進入檢測范圍，范圍是從檢測器到車輛的頂部，小于從檢測器到道路的范圍，從而使檢測器產(chǎn)生一個車輛檢測信號。</p><p><b>　　被動聲吶檢測器</b></p><p>　　行駛車輛產(chǎn)生的聲波能量或者從車輛內(nèi)發(fā)出的可聽見的各種