A pre-processing procedure is designed for a space-surface bistatic synthetic aperture radar （SS-BSAR） system when a time domain image formation algorithm is employed. Three crucial technical issues relating to the ...A pre-processing procedure is designed for a space-surface bistatic synthetic aperture radar （SS-BSAR） system when a time domain image formation algorithm is employed. Three crucial technical issues relating to the procedure are fully discussed. Firstly, unlike image formation algorithms operating in the frequency domain, a time domain algorithm requires the accurate global navigation satellite system （GNSS） time and position. This paper proposes acquisition of this information using a time-and-spatial transfer with precise ephemeris and interpolation. Secondly, synchronization errors and compensation methods in SS-BSAR are analyzed. Finally, taking the non-ideal factors in the echo and the compatibility of image formation algorithms into account, a matched filter based on the minimum delay is constructed. Experimental result using real data suggest the pre-processing is functioning properly.展开更多
【目的】冠层内光合有效辐射和叶片光合生理特性存在较大异质性。探究番茄冠层不同部位叶片光截获和光合能力对行距和灌水量的响应,研究行距和灌水量对番茄冠层光合生产力的影响,并对果实综合品质进行分析,为机械化栽培番茄行距和灌水...【目的】冠层内光合有效辐射和叶片光合生理特性存在较大异质性。探究番茄冠层不同部位叶片光截获和光合能力对行距和灌水量的响应,研究行距和灌水量对番茄冠层光合生产力的影响,并对果实综合品质进行分析,为机械化栽培番茄行距和灌水量的设置提供理论依据。【方法】以番茄为试材,宽窄行栽培,株距35 cm,小行距40 cm,设置3个大行距水平(70cm(P1)、120 cm(P2)和170 cm(P3))和两个灌溉水平(常规灌溉(W1)和轻度亏缺灌溉(W2)),全因子试验,共6个处理,测定各叶位叶面积和光截获量,冠层均分为6个部位,测定叶片净光合速率(photosynthetic rate,Pn)、比叶质量(leaf mass per area,LMA)、叶绿素(Chlorophyll,Chl)及N、P、K含量,并分别以各部位叶面积占全株叶面积的比例或各部位叶片干重占全株叶片干重的比例为权重综合分析各处理冠层光合能力,通过Pearson相关系数分析各指标相关性,测定地上部干鲜重、单株产量及第二穗果品质,采用PCA法和基于博弈论的组合赋权-TOPSIS法对番茄综合品质进行评价并排序。【结果】行距增大对冠层叶面积、光截获和光合能力的影响主要体现在冠层中部和下部。冠层中部叶面积随行距增大表现为先增加后减少,冠层下部叶面积及冠层中部和下部光截获均表现为P1到P2显著增加,P2到P3小幅增加;冠层中部和下部Pn表现为P2较P1提高8.06%—11.32%,P3较P2提高14.25%—24.40%;LMA表现为P2较P1提高1.31%—33.24%,P3较P2提高6.09%—17.86%;Chl含量表现为P2较P1提高3.42%—6.81%,P3较P2提高3.19%—4.96%;N含量表现为P2较P1提高13.89%—34.73%,P3较P2提高2.21%—19.74%;P和K含量无明显规律。整体来看,Pn、Chl和N含量均随行距增大而增加,LMA轻度亏缺灌溉下随行距增大而增加,常规灌溉下表现为P3>P1>P2;3种行距水平下,LMA和N含量均表现为常规灌溉高于轻度亏缺灌溉,Pn表现为P1和P3下常规灌溉高于轻度亏缺灌溉,而P2下轻度亏缺灌溉更高,Chl含量表现为P1常规灌溉更高,而P2和P3轻度亏缺灌溉更高。地上部干鲜重,常规灌溉下随行距增大而增加,轻度亏缺灌溉下随行距增大而先增加后减少;常规灌溉的地上部干鲜重高于轻度亏缺灌溉。两种灌溉水平下单株产量均随行距增大而增加,P1到P2增加幅度较大(常规灌溉和轻度亏缺灌溉下,P2较P1分别增加33.75%和24.32%),P2到P3单株产量仅小幅增加(常规灌溉和轻度亏缺灌溉下,P3较P2分别增加2.87%和4.30%);常规灌溉单株产量高于轻度亏缺灌溉。增加行距、减少灌水量可以优化果实综合品质,综合品质得分前3位为P3W2、P2W2和P3W1。【结论】叶片Pn、LMA、N含量、地上部干鲜重和单株产量为P3W1最大;冠层光截获量、Chl含量及番茄综合品质评分为P3W2最高。展开更多
基金supported by the Electro-Magnetic Remote Sensing Defence Technology Centre (EMRS-DTC) of the UK Ministry of Defence(EMRS/DTC/1/27)the China Scholarship Council (2009611064)the Program for New Century Excellent Talents in University (NCET-07-0223)
文摘A pre-processing procedure is designed for a space-surface bistatic synthetic aperture radar （SS-BSAR） system when a time domain image formation algorithm is employed. Three crucial technical issues relating to the procedure are fully discussed. Firstly, unlike image formation algorithms operating in the frequency domain, a time domain algorithm requires the accurate global navigation satellite system （GNSS） time and position. This paper proposes acquisition of this information using a time-and-spatial transfer with precise ephemeris and interpolation. Secondly, synchronization errors and compensation methods in SS-BSAR are analyzed. Finally, taking the non-ideal factors in the echo and the compatibility of image formation algorithms into account, a matched filter based on the minimum delay is constructed. Experimental result using real data suggest the pre-processing is functioning properly.
文摘【目的】冠层内光合有效辐射和叶片光合生理特性存在较大异质性。探究番茄冠层不同部位叶片光截获和光合能力对行距和灌水量的响应,研究行距和灌水量对番茄冠层光合生产力的影响,并对果实综合品质进行分析,为机械化栽培番茄行距和灌水量的设置提供理论依据。【方法】以番茄为试材,宽窄行栽培,株距35 cm,小行距40 cm,设置3个大行距水平(70cm(P1)、120 cm(P2)和170 cm(P3))和两个灌溉水平(常规灌溉(W1)和轻度亏缺灌溉(W2)),全因子试验,共6个处理,测定各叶位叶面积和光截获量,冠层均分为6个部位,测定叶片净光合速率(photosynthetic rate,Pn)、比叶质量(leaf mass per area,LMA)、叶绿素(Chlorophyll,Chl)及N、P、K含量,并分别以各部位叶面积占全株叶面积的比例或各部位叶片干重占全株叶片干重的比例为权重综合分析各处理冠层光合能力,通过Pearson相关系数分析各指标相关性,测定地上部干鲜重、单株产量及第二穗果品质,采用PCA法和基于博弈论的组合赋权-TOPSIS法对番茄综合品质进行评价并排序。【结果】行距增大对冠层叶面积、光截获和光合能力的影响主要体现在冠层中部和下部。冠层中部叶面积随行距增大表现为先增加后减少,冠层下部叶面积及冠层中部和下部光截获均表现为P1到P2显著增加,P2到P3小幅增加;冠层中部和下部Pn表现为P2较P1提高8.06%—11.32%,P3较P2提高14.25%—24.40%;LMA表现为P2较P1提高1.31%—33.24%,P3较P2提高6.09%—17.86%;Chl含量表现为P2较P1提高3.42%—6.81%,P3较P2提高3.19%—4.96%;N含量表现为P2较P1提高13.89%—34.73%,P3较P2提高2.21%—19.74%;P和K含量无明显规律。整体来看,Pn、Chl和N含量均随行距增大而增加,LMA轻度亏缺灌溉下随行距增大而增加,常规灌溉下表现为P3>P1>P2;3种行距水平下,LMA和N含量均表现为常规灌溉高于轻度亏缺灌溉,Pn表现为P1和P3下常规灌溉高于轻度亏缺灌溉,而P2下轻度亏缺灌溉更高,Chl含量表现为P1常规灌溉更高,而P2和P3轻度亏缺灌溉更高。地上部干鲜重,常规灌溉下随行距增大而增加,轻度亏缺灌溉下随行距增大而先增加后减少;常规灌溉的地上部干鲜重高于轻度亏缺灌溉。两种灌溉水平下单株产量均随行距增大而增加,P1到P2增加幅度较大(常规灌溉和轻度亏缺灌溉下,P2较P1分别增加33.75%和24.32%),P2到P3单株产量仅小幅增加(常规灌溉和轻度亏缺灌溉下,P3较P2分别增加2.87%和4.30%);常规灌溉单株产量高于轻度亏缺灌溉。增加行距、减少灌水量可以优化果实综合品质,综合品质得分前3位为P3W2、P2W2和P3W1。【结论】叶片Pn、LMA、N含量、地上部干鲜重和单株产量为P3W1最大;冠层光截获量、Chl含量及番茄综合品质评分为P3W2最高。
