雷達射系數 的英文怎麼說

中文拼音 [léidáshèxìshǔ]
雷達射系數 英文
radar reflectivity
  • 雷 : 1. （雲層放電時發出的響聲） thunder 2. （軍事上用的爆炸武器） mine 3. （姓氏） a surname
  • 達 : Ⅰ動詞1 （暢通） extend 2 （達到） reach; attain; amount to 3 （通曉; 明白） understand thoroughly...
  • 射 : Ⅰ動詞1 （用推力或彈力送出） shoot; fire 2 （液體受到壓力迅速擠出） discharge in a jet 3 （放出） ...
  • 系 : 系動詞（打結; 扣） tie; fasten; do up; button up
  • 數 : 數副詞（屢次） frequently; repeatedly
  • 雷達 : [訊] radar （縮自 radio detection and ranging）
  • 系數 : [數學] coefficient; ratio; modulus; quotient; factor
  1. The conventional sphere model of earth and circle model of orbit are discarded, and the ellipsoid model and the ellipse model are selected for further research, which achieves a method to determine the target position through the antenna pointing direction. and the spaceborne sar system design and simulation software is brought forth. this software accomplishes sar system coefficients design for antenna area, pulse repetition frequency, signal bandwidth, downlink data rate, radar transmitter power and satellite platform yaw steering

    本文從星載雷達的星地幾何關系入手，舍棄傳統星載合成孔徑雷達研究中的球地球模型和圓軌道模型，研究了在地球橢球模型和橢圓軌道模型下由雷達天線確定目標坐標的方法，並在此基礎上研製了星載合成孔徑雷達系統設計與模擬軟體，完成雷達系統天線尺寸、脈沖重復頻率、信號帶寬、雷達信號數據率、雷達發射功率、衛星平臺的偏航牽引等幾個方面的系統參數設計以及雷達多普勒特性、雷達系統模糊、雷達定位及精度的分析，最後完成雷達回波信號的模擬。
  2. Main conclusions drawn from the analyses of calculating results are as follows : ( 1 ) the microwave absorption of atmosphere gas have obvious attenuation at the wavelengths for cloud detection, thereinto, the water attenuation effect changes greatly, so the 94ghz cloud detecting radar should have water vapor attenuation correction scheme. ( 2 ) when 37ghz and 94ghz radars detect clouds, the difference between the atmosphere and cloud attenuation and the large variety of radar reflectivity conduce the intension of the radar backscatter signals change. ( 3 ) for the thin cloud layer and low water content of cloud, 37 - ghz radar backscatter signals are not as good as 94 - ghz radar, that is to say that the 94ghz radar has better capability in thin clouds detection

    本工作得出如下結論： （ 1 ）大氣氣體的微波吸收在測雲波段產生明顯的衰減，其中水汽衰減效應變化很大；即將上天的空間94ghz測雲雷達必須有水汽衰減訂正方案； （ 2 ） 37ghz和94ghz雷達測雲，由於大氣和雲衰減不同和雷達反射率的很大差異，導致雷達回波信號強弱不同； （ 3 ）對雲層較薄、含水量較少的雲，在不計雷達參數的情況下， 37ghz雷達回波信號不如94ghz測雲雷達，也就是說94ghz對薄雲有更強的探測能力；對雲層較厚、含水量大的雲，由於強衰減的作用， 94ghz雷達回波信號小於37ghz雷達； （ 4 ）從大氣衰減的不利因素方面考慮，空間94ghz雷達測高層薄雲的效果最好；測低層薄雲時需要考慮氣體衰減訂正；因濃厚雲的強衰減作用，探測其中下部的能力大大減弱，不僅要進行衰減訂正，而且要藉助其他信息來反演整個雲層的含水量垂直分佈； （ 5 ）為了獲得從極薄到極濃厚雲的垂直分佈探測能力，未來測雲雷達系統最好採用雙波長甚至三波長（如94 、 37和13ghz ） 。
  3. As for a space - based cloud radar, the change of the radar reflectivity n and the change of attenuation rate along with the cloud liquid water content have been compared between 37 ghz and 94ghz. the transmittance t of single level cloud for different heights and liquid water content has also been calculated at 2 frequencies. by defining a = n tr, which combines both effects of radar reflectivity and transmittance, we have examined the values of a at 37ghz and 94ghz for high, middle and low cloud liquid water contents

    對空間測雲雷達，討論了37ghz和94ghz這兩個頻率的雷達反射率和衰減系數隨雲液水含量的變化；計算了不同高度的單層雲在不同頻率，不同含水量情況下的雲層透過率_ ；定義a = _來綜合考慮雷達反射率和透過率對空間測雲雷達回波的影響，分析比較了雲含水量高、中、低時37ghz和94ghz的a值大小。
  4. An array of lasers fitted on the car bumpers, radar and global positioning systems feed data into the on - board computer to determine its location and position

    汽車緩沖器上被安裝了一排雷射燈，雷達和全球定位系統隨時將數據傳入車載計算機用以確定位置。
  5. Validation of the presented approach is verified through numerical simulations of radar measurements over the bare soil surfaces

    本研究以裸露土之土壤?度及其雷達散射系數的數值模擬來驗證此一方法之有效性。
  6. At present greco is regarded as one of the most valuable methods of radar cross section ( rcs ) computation in the high - frequency region. depending on these conditions, several researches have been completed in this paper : firstly, calculating rcs of complex conducting targets has been accomplished by greco method. the high - frequency rcs of targets are obtained through physical optics ( po ) and incremental length diffraction coefficients ( ildc ) respectively

    本論文做了以下研究工作：首先，實現了運用greco方法計算了高頻區理想導體復雜目標的雷達散射截面（ rcs ） ，分別應用了物理光學法（ po ）和增量長度繞射系數法（ ildc ）計算了目標的面元和棱邊的電磁散射，最後綜合面元與棱邊的散射效應得到目標的總rcs 。
  7. This dissertation bases on the research of battlefield armored reconnaissance tank system, which is a very important reconnaissance & information reception means for our country ? digital armored troops. the zzco2 radar armored reconnaissance tank system is the collector of radio information by use of the radiation and reflection of electromagnetic wave, at the same time it is a system which saves, processes and transmits the radar information picked up. the content of this dissertation involves the design and development of zzco2 ? software system

    本論文以我軍裝甲機械化部隊坦克師的戰場裝甲偵察系統的研製為背景撰寫。該系統是我國數字化裝甲部隊的重要偵察和信息獲取工具。其中zzc02型雷達偵察車（型）是該系統的前沿偵察車，是不可見電磁頻段的雷達信息的收集者，是以電磁波輻射、反射作為信息獲取的主要手段，以計算機主機為中心的信息採集、處理、存儲和傳輸系統。
  8. For parameter a, there is a close relationship exist between a ( 9, sr ) in two different radar incident angle that can be expressed as : with considering the effects of soil texture, we get the final expression of the inversion model : where mv ( t1 ), mv ( t2 ) is volumetric soil moisture content in two different temp, c, d is soil type related parameters, and v ( t1 ), s ( t2 ) is coresponding bare soil radar backscattering coefficients. inversion results show that for the c band hh polarized radarsat scansar data with a range of incidence angle from 20 to 40, the soil moisture change value can be derived with an acceptable accuracy using the above model. the temporal and spatial soil moisture change patterns are associated with rainfall and vegetation cover, as well as the soil hydraulic characteristics

    利用最新發展的電磁波散射模型研究了不同植被覆蓋地表雷達波對地表土壤水分的敏感性，建立了半經驗植被雷達後向散射模型; 2 ） .研究發現在農作物等矮小植被覆蓋地表，植被層直接後向散射與植被類型相關，且在植被生長期，雷達後向散射系數對植被含水量的敏感性要高於對植被高度變化的敏感性; 3 ） .解決了單參數雷達地表土壤水分反演問題中，雷達入射角和地表粗糙度的影響這一難點問題; 4 ） .利用土壤介電模型校正了不同土壤類型對反演地表土壤體積含水量的影響; 5 ） .在以上成果基礎上，建立了完整的單參數雷達地表土壤水分變化探測反演演算法，經地表驗證，模型反演地表土壤水分變化值的精度為rmse = 0
  9. Based on rain drop size distribution ( dsd ) data measured in qingdao, guangzhou and xinxiang, the radar reflectivity factor z for spherical rain drops, the radar reflectivity factor zh and differential reflectivity zdr for oblate ellipsoid rain drops have been calculated. the relation of reflectivity and rainfall rate for conventional meteorological radar and the relation of reflectivity, differential reflectivity and rainfall rate for multiparameter radar are regressed, the performance difference of two kinds of radar for measuring rainfall and difference for measuring rainfall in different regions are also discussed

    基於我國青島、廣州和新鄉地區雨滴尺寸分佈數據，計算了球形雨滴雷達反射因子，橢球形雨滴雷達水平極化反射因子和差分反射率，回歸給出了這些地區的常規氣象雷達反射因子與降雨率的經驗關系和多參數雷達水下極化雷達反射因子、差分反射率和降雨率關系，並對其測雨精度和地區差異進行了比較。
  10. Abstract : the effects of airfoil geometric parameters on wing " s spacial and polarized scattering characteristics have been systematically revealed. the results of the study indicated that the calculating value of diffraction from trailing edge by using the formula of the straight wedge is very far from experimental results for vertical polarization, and the contribution of thickness of the trailing edge to scattering must be considered in the calculation. the scattering peak of leading edge depends only on radius of airfoil for horizontal polarization. but for vertical polarization, it depends on maximum thickness and the location of maximum thickness. engineering formulas for evaluating all scattering peaks were given in the paper. it is important for the design of low - rcs wing

    文摘:系統地揭示了翼形幾何參數對機翼的空間散射特性、極化散射特性的影響規律.研究發現，在垂直極化狀態下用理論尖劈公式計算機翼后緣繞射的計算結果與實驗結果相差甚遠.提出在垂直極化狀態下機翼后緣繞射的計算必須將后緣厚度考慮在內的見解.對於水平極化，前緣散射波峰只與前緣半徑有關；而對於垂直極化，前緣散射波峰與翼形最大厚度以及最大厚度位置有關.給出前後緣散射波峰的工程估算公式，為低雷達散射截面（ rcs ）機翼設計提供依據
  11. Ais works on the marine vhf, use the sotdma ( self organized time division multiple access ) data chain protocol to transfer data of ships. the ais can help the limits of the current services, and decrease the collide case of ships, and improve the value of the safe action in marine, and make the content of the radar and the vts more stronger

    船舶自動識別系統（ automaticidentificationsystem ，簡稱ais ）工作在海上vhf頻段，運用sotdma方式發射船舶數據，具有補充現有船舶導航存在的缺陷，減少船舶碰撞事故；提高搜救船舶海上救助的速度；增強雷達、船舶交通管理系統vts的功能。
  12. ( 2 ). according to the system indices and requirements together with the technology characteristic, it researches the capture possibility of apt capturing system. then it introduces the common scan methods, such as raster, spiral, raster spiral, rose and lissajo. ( 3 ). it makes a detailed simulation analysis of the raster and spiral scan, analyze the connection between capture probability, capture time, system index at different capture resolution angle, capture range, vibration angle extent and terminal location distributing mean square deviation

    其中對幾個關鍵部分進行了詳細分析:計算了目標角反射器的激光雷達散射截面（ lrcs ）值，研究了qd與ccd對目標位置角度的計算方法和空間解析度; （ 2 ）根據系統指標和要求並結合現有國內技術特點研究了apt捕獲系統掃描的捕獲概率問題，然後分析了幾種常見的掃描方式:矩形（ raster ）掃描、螺旋（ spiral ）掃描，矩形螺旋（ rasterspiral ）掃描，玫瑰形（ rose ）掃描以及李薩如形（ lissajo ）掃描; （ 3 ）對分行掃描和螺旋掃描進行了詳細的模擬分析，分析了它們在不同捕獲分辨角、捕獲范圍、振動角振幅和終端位置分佈均方差時的捕獲概率、捕獲時間與系統常數之間的關系。
  13. Based on the vector radiative transfer theory and the characteristics of the sar technology, several sub - models for rice backscattering are constructed, including the leaf scattering model, the leaf extinction model, the trunk scattering model, the trunk extinction model and the water reflection model. then an integrated model for the first - order scattering mechanisms of rice, including all the main physical processes, is achieved

    針對合成孔徑雷達sar的技術特點，以水稻為研究對象，從矢量輻射傳輸理論vrt出發，通過模擬水稻主要器官稻葉和稻桿對電磁波的散射衰減作用等物理過程，建立了一套完整的水稻一次後向散射作用的物理模型，用以模擬水稻層的後向散射系數
  14. We, then, parameterized a semi - empirical model for the different land surface cover types. this semi - empirical model was applied to minimize the effects of the vegetation volume scattering and extinction in radar measurements

    此外，目前星載合成孔徑雷達如ers - 1 2 、 radarsat等均為單一頻率、單一極化的雷達，無法從得到的單參數雷達後向散射系數中直接提取地表土壤水分信息。
  15. This technique is mainly involved two steps : 1 ) vegetation effects correction : we used ndvi ( normalized difference vegetation index ) derived from tm and avhrr measurements for spatial and temporal variations of vegetation covers at different scales

    但由於電磁波與地表相互作用的復雜性，雷達後向散射系數除受地表介電常數（土壤水分）影響外，還受到地表粗糙度、土壤類型、植被覆蓋以及雷達入射角、頻率、極化等多種因素的影響。
  16. Using a simple radiative transfer model for vegetation volume scattering and the integral equation model ( ibm ) for surface scattering with the field in situ measurements as the input, we compared the simulated and sar measured backscattering coefficients in different agricultural fields

    特別是在植被覆蓋地表，對其下土壤水分的監測更帶有極大的困難性。因此，利用雷達後向散射系數反演土壤水分必須首先充分理解微波與地表的相互作用過程。
  17. 2 ) radar incidence angle and surface roughness correction : to make radar incidence correction and eliminate the surface roughness effects, a wide range of surface parameters ( soil moisture, surface rms height, correlation length, incidence angle ) was input to the ibm model to simulate the effect of surface roughness and radar incidence angle on the sensitivity of soil moisture to the radar backscattering coefficient. a simple model was established to simulate the effects of incidence angle and surface roughness. 3 ) establishment of soil moisture change inversion model : according to a modified ibm model simulation results, the bare surface backscattering coefficients can be expressed as a funtion of the dielectric component for a given surface roughness when the surface slope greater than 2. 0, which is valid for most nature surface : in above equation, r0 is the surface reflectivity at normal incidence

    本研究中，首先利用基於微波輻射傳輸方程的微波植被模型和積分方程（ iem ）模型模擬了各種地表土壤水分含量情況下，植被覆蓋、地表粗糙度（包括地表均方根高度和相關長度） 、雷達入射角對c波段（頻率4 . 7ghz ）水平極化（ hh ）雷達後向散射系數的影響，在此基礎上，建立模型消除了植被覆蓋、地表粗糙度、及雷達入射角對雷達後向散射的影響，利用多時相50m解析度radarsatscansar雷達後向散射系數圖像反演得到了地表土壤水分變化模式信息。
  18. The second channel is a transponder with no guard. it can be used in the relay communication system and can be composed into a data platform with remote control if additional terminal equipment is added. its application in other systems is also discussed

    而乙機通道是一個無人職守的轉發器通道，除了直接可用於接力通信系統中外，如果增添適當終端設備還可構成具有遙控功能的數據報告平臺，論文給出了本防撞雷達射頻通道應用在其它系統中的實例。
  19. In this study, we demonstrate a technique using the multi - temporal c band hh polarized radarsat scansar data to estimate the relative soil moisture change. the experiment data from sgp97 covered a whole range of vegetation growing season and different type agriculture fields

    研究證明，星載合成孔徑雷達（ sar ）得到的地表後向散射系數與地表介電常數有直接相關關系，從而能夠在水文模型要求的精度范圍內有效提取地表土壤水分信息。
  20. The relationship of the moisture content and radar scattering coefficient is built into the measurement equation, while the dry - up ( or wet - down ) of soil moisture in multi - temporal states was modeled into the process equation

    土壤濕度與雷達散射系數間的對映關系是以量測方程序來表示，而土壤濕度在時序上漸干或漸濕的狀態變化則以處理方程序來表示。
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