Ứng dụng phổ kế siêu cao tần trong viễn thám hàng không xây dựng bản đồ độ ẩm đất

Tieu ban: Cong nghe thong tin - Tir dong hod - Cong nghe I'u tru ISBN: 978-604-913-010-6<br /> <br /> <br /> <br /> tTNG DUNG PHO KE SIEU CAO T A N TRONG VIEN THAM HANG<br /> KHONG XAY DlTNG BAN DO DO A M D A T<br /> <br /> Doan Minh Chung, Vo Thj Lan Anh, Vii Trung Kien,<br /> Phung Diic Thuong, Bui Huy, Ngo Tuan Ngoc*<br /> Vien Cdng nghe Vii try<br /> 18 Hoang Qudc Viet. Cau Giay, Ha Ndi<br /> Email: dmehung@sti.vast.ac.vn<br /> Tom tat<br /> Trong 10 ndm (2000-2010) hgp tdc khgg hoc cdng nghe vdi Vien Dien td - Vien<br /> HLKH Bunggri. cdc cdn bd ihudc Vien Vdt Ly, ngy chuyen sang Vien Cdng nghe vit<br /> tru, dd chi tgg thdnh cdng 3 he phd ke sieu ccio tdn bdng L (I.4GLIz). C (3.5GHz)<br /> vd X (10.95GHz) vd irng dung chimg trgng dieu trg vd nghien ciru mdi trudng nhu<br /> dd dm ddt. sinh khdi thuc vdt, do man mrdc bien. Cdc ket qua dd dugc bdo cdo tgi<br /> nhieu hdi nghi trong vd ngodi nude vd ddng tren cdc tgp ehi chuyen ngdnh.<br /> Trong 2 ndm 2007-2008, thuc hien di tdi cdp Vien KHCNVN 'Nghien ciru tich<br /> hgp mdy thu GPS vdi he phd ke sieu ego tdn vd irng dung thir nghiem phuang<br /> phcip vien thdm hdng khdng xdy dung bgn dd do dm ddt vimg ddng bdng trung du<br /> Bdc bd", nhdm cdn bd nghien ciru Vien Cdng nghe vit tru dd ldp ddt 2 he phd ke<br /> (bdng L&C) len mdy bay true thdng, bay doc theo 2 viing ddt thugc huyen Ba Vi<br /> vd Gia Ldm. Hd Not de thu phd birc xg tu nhien eug ddng lug. tir dd xdy dung bdn<br /> dd dd dm ddt. Sd lieu do dd dugc phdn tich, tinh todn vd bdn dd hod do dm ddt<br /> lap be mat. sgu khi hieu chinh dnh huang eug lap thdm thuc vcit Id ddng liia. Ket<br /> qud cua de tdi dd khai thde irng dung cua vien thdm hdng khdng ddi vdi cdc ddi<br /> tugng tu nhien ed dien tich lan vd ddng nhdt (nhu rirng, ddng lua, bien).<br /> Abstract<br /> In ten years (2000-2010) of scientific and technological cooperation with the<br /> Institute of Electronics - Bulgarian Academy of Sciences, the seiendsts of the<br /> Institute of Physics, ngw nwved lo the Space Technolog}' Institute (STI) of VAST<br /> ha\'e successfully manufactured 3 microwave radiometers (MW RDMs) with L<br /> (1.4GHz). C (3.5GHz), L-band (I0.95GHz) and their investigations for environment<br /> research and monitoring such as soil moisture, vegetation water content, sea<br /> surface sglinity. The studied results hcive been reported at mony national and<br /> international conferences as well as published in specific research journals.<br /> In t^vo years 2007-2008, implementing the VAST's research project "Research<br /> and integration of GPS receiver with the MW RDMs and trial application of the<br /> aerial remote sensing method to establish the soill moisture map for the North<br /> Vietnam middle high basins ", the scientist group of STI have hung the L&C-band<br /> RDMs to the helicopter, to fly along the rice fields ofBa Vi and Gia Lam, Ha Noi<br /> region to capture the MW emission of the rice fields, through thgt tg establi.sh the<br /> soil moisture map of the observed fields after correction of the rice cover<br /> influence. The successive results of the project have investigated the aerial remote<br /> sensing apllieation for the natural objects homogenous stretch over a large area<br /> like forest, rice field and sea suifaee.<br /> <br /> <br /> 30<br />  Hoi nghi Khoa hoc ky niem 35 ndm I'ien Khoa hoc vd Cong nghe Viet Nam - Hd Noi 10 2010<br /> <br /> <br /> <br /> I. Gioi thieu chung<br /> Van de quan ly nguon nude trong ndng nghiep cd the dugc eai thien kip thdi thdng qua \'iee<br /> theo ddi do am dit. Tuy nhien. cac phep do truyen thdng da trd nen khdng thuc tl khi dp am<br /> dat bien ddng kha lan ve ca thdi gian \'a khdng gian, viec giam sat do am dat can dugc tiln<br /> hanh d dien rdng, hoac d viing xa xdi. hiem trd ma con ngudi khd den dugc.Vi vay, cdng<br /> nghe vien tham da va dang dugc img dyng rdng rai trong danh gia va giam sat do am dat.<br /> Cac nghien ciiu trudc day da cho thay mdt sd sensor cam img cd the dugc dimg de xac dinh<br /> do am dat be mat [1,4,6]. Cac he phd ke sieu cao tan dugc cho la thich hgp trong viec xac<br /> dinh do am dat \'i tinh dn dinh cao. su dung dugc trong cac trudng hgp gan tren ve tinh. may<br /> bay, tram mat dat va khdng phu thude \'ao may, ngay/dem.<br /> Tir nam 2002 - 2006. nhdm chuyen gia thude Vien Vat Ly, sau chuyin vl Vien Cdng nghe<br /> vu try da hgp tac vdi Vien Dien tir, Vien HLKH Bungari ehl tao thanh cdng 2 he phd kl sieu<br /> cao tan bang L & C, da hgp tac vdi nhieu co quan nhu Vien Dia ly, Vien Vat Ly thude Vien<br /> KHCNVN, Vien KH Khi tugng Thuy \'an \'a Mdi trudng, v.v. nghien cim do im dit bing cac<br /> phd ke sieu cao tan, dat ket qua kha quan (Hinli 1).<br /> <br /> <br /> <br /> <br /> Hinh I. Anh chup he phd ke bdng L & C do do dm sinh khdi ddng ngd vd nhiet do mdt bien<br /> Bai viet nay md ta tdm tat phuang phap va cac kit qua dat dugc ciia dl tai eip Vien<br /> KHCNVN nam 2007-2008 "Nghien ciiu tich hop may thu tin hieu GPS voi he pho ke sieu<br /> cao tan va iing dung thu nghiem vien tham hang khong xay dyng ban do do im dat<br /> vimg dong bang Trung du Bac bo", do Vien Cdng nghe vii try chu tri thyc hien.<br /> Myc tieu ciia de tai la tien hanh do do phat xa ty nhien eiia dit va ldp phii thuc vat (liia, cd)<br /> bang cac phd ke sieu eao tan (bang L & C ) dugc lip dat tren may bay, kit hgp vdi cac phep<br /> do thyc dia m§t dat, tir dd xay dung ban dd do im dit viing nghien ciin nhim theo ddi biln<br /> ddng do am dat theo thdi gian va khdng gian, phyc vy giam sat, quan ly tai nguyen nude va<br /> mdi trudng.<br /> II. Phuong phap thuc nghiem<br /> 2.1. Gidi thieu chung:<br /> Vdi myc dich la danh gia do im dit bing phuong phap vien tham SCT thy ddng va sy biln<br /> ddng ciia do am dat tren mdt viing rdng Idn giiia miia khd (thang 11-12) va miia mua (thang 5-<br /> 6). tren mdt viing dat kha rdng, cd dac trung biln ddng Idn vl do im dit \'a cd gia tri kinh tl vl<br /> cay cdng - ndng nghiep, phuang phap nghien cim dugc lya chgn la Vien thim hang khdng<br /> (Aerial remote sensing, ARS), viing nghien cim dugc lya chgn la viing ddng bing Trung du Bic<br /> bd. cd ddng bang va ddi ddc. lay \iing ndng nghiep trong lua Ba Vi va Gia Lam lim trong tam.<br /> <br /> 31<br /> Tieu ban: Cong nghe thong tin - Tu dong hod - Cong nghe 1 'u tru ISBN: 978-604-913-010-6<br /> <br /> <br /> <br /> Tren co sd ghi nhan phd phat xa sieu cao tan. dugc thu bai 2 he phd kl bang L & C treo<br /> tren may bay, ket hgp vdi tin hieu may thu GPS tieh hgp vao chuang trinh thu nhan tu ddng<br /> ciia cac phd ke, chiing ta se ghi dugc phd phat xa sieu cao tin trong thdi gian thuc ciia cac ddi<br /> tugng tir nhien nam trong viing thu ciia anten phd ke klii bay qua. Dya tren phd phat xa thu<br /> dugc, do am dat (thudng bi che phii bdi \&p tham thyc vat) se dugc tinh toan dua theo cac md<br /> hinh ban thuc nghiem va cac phep do thyc dia mat dat. Sau dd tich hgp vdi toa do bay dugc<br /> xac dinh bdi may thu GPS, cac ket qua do am dat dugc gan \ao tga do thuc, tir dd xay dung<br /> thanh ban dd do am dat ciia vimg nghien cim.<br /> Nhdm can bd dl tai da hgp ddng vdi Cdng ty dich vy bay mien Bac (Gia Lam), thyc hien<br /> hcrp ddng ky thuat lip dat cac thilt bi Ien may bay va tien hanh bay. Hgp ddng dugc thyc hien<br /> bay 2 lin vao cac nam 2007-2008 bing may bay tryc thang MI-I7.<br /> Theo hgp ddng, may bay tryc thang bay phyc vy thi nghiem d do cao h ~ 100-150m, bao<br /> dam tranh dugc nhieu tap am tir cac ngudn phat sdng tir mat dat va bao dam do chinh xac cho<br /> phep do. Sai so vl do cao 0.5% khdng gay anh hudng dang ke den ket qua do eiia phd ke sieu<br /> cao tin, nhit la ddi vdi tin sd f < 6 GHz [I]. Gdc md eiia anten phd ke bang L la 30*^, nen vet<br /> (foot print) ciia anten cd dudng kinh d ~ 2.tg(15°).h = (107 - 161)ni ; Ddi vdi phd ke bang C,<br /> gdc md bing 15^, vlt cd dudng kinh dc ~ 2.tg(7.5'').h ~ (52 - 79)m May bay bay cham voi<br /> tdc do khoang V ~ 120 km/h = 33 m/s, nghTa la phd ke cd the lay mau tir 2 - 5 lan trong I vet<br /> do eiia anten (vi phd ke lay mau do Is / lan). Dieu nay bao dam phep do eiia phd ke tren may<br /> bay dap irng dugc do « tinh » cua phd ke. Vdi chieu dai bay dgc theo vimg quan sat khoang L<br /> ~ 20,000ni, thi thdi gian bay mdi dudng la t = 20,000/33 ~ 600s = 10 phut, cd thi ghi dugc<br /> 600 sd lieu cho mdi dudng bay, dii do chinh xac yeu cau. Theo cac chuyen gia hang khdng,<br /> may bay true thang loai nay se dat do rung thap nliat khi bay d tde do V~120 km/h. Sai sd chii<br /> yeu do sy rung lac ciia may bay lam thay ddi gdc tdi ciia anten. Cd the hieu chinh sai sd nay<br /> bang cac md hinh ban thyc nghiem [4,8,11].<br /> <br /> De cung cap cac sd lieu ve loai dat, thanh phan dat, sinh khdi thyc vat, v.v., ddng thdi vdi<br /> qua trinh do tir may bay, mdt nhdm can bd tien hanh do thyc dia mat dat tai cac diem xac dinh<br /> ciia viing nghien cim ma may bay bay qua, va mdt nhdm khac se thu anh ve tinh MODIS de<br /> kiem chirng ket qua do vien tham hang khdng.<br /> 2.2. Khu vuc bay do thuc nghiem Ba Vi:<br /> Trong chuyen bay thir nghiem dau tien (nam 2007), phd kl sieu eao tin bang C dugc lip<br /> dat dudi bung ciia may bay tryc thang MI-17, vdi gdc quan sat 9=0" (nadir).<br /> Myc dich ciia thi nghiem:<br /> - Kiem tra dp chinb xac va dn dinh ciia phd kl sieu cao tin bang C khi boat ddng tren may<br /> bay \'di tdng thdi gian bay do la 60 phut.<br /> - Kiem dinh \'a pban ticb do phat xa kliac nhau giira cac ddi tugng: dit trdng, dong lua, cay<br /> cdng nghiep, nha cira, sdng ho.v.v...Phan tieh cac ylu td anh hudng din sd lieu do eiia pho kl<br /> dat tren may bay so vai do dudi mat dit.<br /> - Xac dinli dg phat xa ciia cac ddi tugng mat dit va tham thyc vat trong dien tich do bay, tir dd<br /> tinh toan do am dat \'a do am sinh khdi thirc vat.<br /> - Tdng hgp cac ket qua da dugc xir ly, xay dung ban do do im dit viing nghien ciru.<br /> Sau klii khao sat \'iing bay do, de tai da thong nhit vl quy dao bay, gdm 4 dudng sau:<br /> - Viing bay do thude cac xa La Phii, Hoang Xa, Xuan Son thugc huyen VTnh tbiiy, xa VTnh<br />  Hoi nghi Khoa hoc ky niem 35 ndm Vien Khoa hoc vd Cong nghe Viet Nam - Hd Not 10 2010<br /> <br /> <br /> <br /> Thinh, tbudc huyen Ba Vi, Ha Ndi, cd khung toa dd dia ly la 105*'28"76"", 21°05"48"" va<br /> 105°28'76'',2I°I2'18".<br /> - Dudng bay do theo hudng Ddng - Tay vdi chieu dai mdi dudng la 20km, khoang each<br /> giiia cac dudng bay la 4 km. Tdng sd dudng bay do la 4.<br /> - Tdng dien tich khu vyc bay do khoang 240km".<br /> - Chieu cao bay: 80-lOOm. Van tdc may bay khi do: lOOkm/h<br /> - Do thang bang khi bay do: dn dinh khdng vugt qua: ± 3°.<br /> •4| 19-> 20km ^<br /> lOS-irss" 105-28'76-<br /> ><br /> A 105°17'12"<br /> <br /> <br /> <br /> L05°17'4"<br /> i<br /> 4km 105''28'76" 7<br /> <br /> t<br /> ^ IOS'17'4" 105*2876"<br /> —#- ...........<br /> <br /> Cac thiet bi do trong thi nghiem bao gdm:<br /> - 01 phd ke bang C (f = 3.5 - 3.7 GHz, AT < 0.3K), dugc gin tren may bay va dugc dilu<br /> khien ty ddng bang chuang trinh cai dat trudc. Sd lieu do dugc ty ddng thu thap, xir ly, biln<br /> thi phd "on-line" bang chuang trinh phin mim Radiometer 4.0.<br /> - May quay phim, may anh sd de ghi tu lieu anh cac khu vuc may bay bay qua, lam co sd dl<br /> phan tich phd tin hieu do cua phd kl.<br /> - Thiet bi do va lay mau dat, mau liia, ngd.<br /> Sau khi chuan hoa phd kl tai san bay, ghep ndi phd kl va thilt bi thu GPS vdi may tinh xach<br /> tay len may bay de thyc hien viec do dac sd lieu, may bay da cit canh bay din khu vuc do da<br /> dinh san theo toa do.<br /> 2.3. Khu vuc Gia ldm, Hd Ngi<br /> Sau chuyen bay do nam 2007, dl tai riit kinh nghiem nam 2008 bay do khu vyc ddng liia<br /> Gia Lam (sat vdi dudng cao tdc di Bic Ninh - Lang Son), vi dong liia d day rdng va thuin<br /> chiing hon. De tai cung h^n che dien tich bay, bay day dac hon dl tang cudng do chinh xac<br /> cho phep do do am dat. D I tai sir dyng 2 phd kl (L&C), tuy nhien trong qua trinh do, phd kl<br /> bang L da bj treo. khdng boat ddng dn dinh, nen chi ed sd lieu ciia bang C.<br /> - Viing bay do tbudc cac xa Phii Ddng, Ninh Hiep, Phii Chin, Trung Miu, Gia Lam, Ha Ndi,<br /> cd khung toa do dia ly la 105°56'34", 21°02"29,7" va I05°59'27", 21^^05'12,5"".<br /> - Hudng bay Ddng - Tay vdi chieu dai moi dudng la 5km, khoang each giira cac dudng<br /> do la 1 km. Tdng sd dudng bay do la 6. Tdng thdi gian bay do la 60 phut.<br /> - Tdng dien tich khu vyc bay do khoang 30 km^.<br /> - Do cao bay do ~ (70-100) m . Van tdc may bay khi do ~ (80-100) km/h<br /> - Do thang bang khi bay do: dn dinh khdng vugt qua: ± 3".<br /> So dd dudng bay do dugc xac dinh nhu sau:<br /> <br /> <br /> <br /> <br /> 33<br />  ISBN: 978-604-913-010-6<br /> Tieu ban: Cong nghe thong tin - Tie dong hod - Cong nghe ITt tru<br /> <br /> <br /> <br /> <br /> A 2l'OS'12t"<br /> , 1<br /> 21°C|5'1I.S<br /> <br /> 21°04'dO" ^ u m ^<br /> <br /> <br /> <br /> <br /> 105°S6'34' ^ F ^ ^^^ 105°58'S2" '<br /> <br /> 21=o:'29 r 2 2#!t"'<br /> . ailDl^^Tl<br /> <br /> <br /> <br /> Dl xac dinh anh hudng ciia ldp thuc vat din kit qua do do am dat bang phuong phap vien<br /> tham, cin phai xac dinh do im sinh khoi thuc vat bing phuong phap kinh dien.^Cac can bd<br /> VienDia Ly da cit din tan goc cac cay liia trong Im^ dien tich. can tuoi tai chd (sinh khdi<br /> Ly aa car cen lan goc cau *-ay lua uuug im uiyn iiv.ii, •y^^^ -.^^^ -v' v- —--<br /> tuoi), sau i<br /> dd mang vl phdng thi nghiem siy klid va can lien tilp din khi khdi lugng ciia 2 lan<br /> say lien tiep<br /> ilp bing nhau (sinh khdi khd). Sy chenh lech khdi lugng giua sinh khdi tuoi va sinh<br /> khdi khd chinh la dd im sinh khdi. Kit qua do dugc the hien trong bang 1.<br /> <br /> <br /> <br /> <br /> //;/;/; 2. Ldp ddt phd ke dudi bung mdy bay vd chudn bi cdt cdnh<br /> <br /> Bdng 1; Sd lieu do dm sinh khdi ddng lua vimg Gia Ldm<br /> TT Sin 1 khoi tuoi Sinh khoi kho Do am sinh khoi<br /> g/0.25m-' Kg/ha Kg/m' g/0.25m' Kg/ha Kg/m' Kg/m'<br /> SGLl 1101.41 44056.4 4.41 204.45 8178 0.82 3.59<br /> SGL2 518.51 20740.4 2.07 104.33 4173.2 0.42 1.66<br /> SGL3 206.25 8249.8 0.82 34.48 1379.3 0.14 0.69<br /> SGL4 886.81 35472.4 3.55 186.23 7449.2 0.74 2.80<br /> SGL5 717.35 28694 2.87 143.47 5738.8 0.57 2.30<br /> Vdi cac tham sd thu dugc tir cac bang 1, ap dung cac md hinh ban thyc nghiem ciia<br /> T.J.Jackson & T.J. Schmugge [7] va md hinh Wang - Schmugge [10], se hieu chinh dugc anh<br /> hucmg ciia ldp thuc vat va xac dinh dugc do am ldp dit phia dudi.<br /> Hinh 3 md ta so dd khdi tinh toan do am dit tir phd gia tri do ciia phd ke bang C dat tren<br /> may bay. vdi sy hieu chinh anh hudng ciia ldp phii thyc vat (liia, ngd, cd).<br /> Hinh 4 md ta giao dien ciia phan mem Radiometer 4.0 ty ddng thu nhap sd lieu do eiia phd<br /> ke, tinh toan \a hien tbi on-line cac thdng sd mdi trudng quan tam (do am dat, sinh khdi thyc<br /> vat, V.V.). do cac tac gia ciia de tai xay dung nam 2007 [12].<br /> <br /> 34<br />  Hoi nghi Khoa hoc ky niem 35 ndm Vien Khoa hoc vd Cong nghe Viet Nam - Hd Not 10 2010<br /> <br /> <br /> <br /> HI. Xu ly so lieu do vien tham hang khong xac djnh do am dat<br /> Trudc khi tien hanh thi nghiem bay do, can chuan hda cac phd ke tai mat dat, hieu chinh \'a<br /> ddng bg thdi gian thue eiia cac thiet bi nhu phd ke, may tinh, may thu GPS. may anh, camera,<br /> ddng hd thdi gian. Viec nay rat quan trgng cho qua trinh phan loai ddi tugng va xir ly so lieu.<br /> Phan loai cac ddi tugng tren mat dat la budc quan trgng dau tien de nhan dang dung phd tin<br /> hieu thu dugc tir tren may bay \'a ap dyng cac sd lieu thu dua chiing vao cac md hinb tinh toan<br /> (Fresnel, Wang - Schmugge...), tir dd tinh ra do am dat.<br /> Hiiih 5 la phd tin hieu tdng hgp thu dugc (dang tin hieu ra eiia phd kl bang C la tin sd) eiia<br /> cac ddi tugng dudi mat dat khi may bay bay qua trong thdi gian 60 phiit va vimg bien do cua<br /> phd tin hieu phat xa eiia cac ddi tugng sau khi phan loai.<br /> So lieu do thuc dia Tinh £(\\'si) cua dat Gan Wsi = 0+i.0.1 i<br /> Tlh6nckhi. SF(%). theo mo hinh = 1.2.... (do am dat<br /> CF(%). BD(g/cm')<br /> ^<br /> Wang - Schmugge gia djnh)<br /> <br /> <br /> Tinh He so phan xa theo<br /> cong thirc Fresnel r(9.E)<br /> ''<br /> Do phat xa esi= l-Fj ,9,E)<br /> esi= l-riiG.e,<br /> <br /> Gan es - dp phat xa cua ^'<br /> dat sau hieu chinh anh So sanh 5= ! es - esi 1<br /> huong cua lop thirc vat<br /> <br /> t<br /> <br /> <br /> <br /> <br /> Htnh 3; Sa dd khdi tinh todn dd dm ddt cd hieu chinh dnh hirdng ciia lap thuc vdt<br /> <br /> <br /> <br /> <br /> Hinh 4; Giao dien cua chuang trinh thu nhdn vd xu ly sd lieu Radiometer 4. i<br /> Tieu ban: Cong nghe thong tin - Tu dong hod - Cong nghe Vu tru ISBN: 978-604-913-010-6<br /> <br /> <br /> <br /> Viec phan loai cac ddi tugng ty nhien dudi mat dat dya vao thdng tin tdng hgp nhu sau:<br /> - Toa do GPS gin tren may bay lien tyc cap nhat vao may tinh tga do khu \arc bay qua;<br /> - Hmh anh ghi dugc tir camera gan tren may bay ghi nhan ddi tugng vdi thdi gian thyc;<br /> - Phd gia tri phat xa thu dugc tir phd ke tren may bay ciia cac ddi tugng eiing loai ed gia<br /> tri gan bang nhau;<br /> Hinh (6 - 8) md ta kit qua phan loai cac ddi tugng dudi mat dat va cac bii IL; it ;si«' ji j.tti?<br /> u 'H.' ^.-M/ ;.;ija)j:>'L:.i. fit-, tt ; : * ;i<br /> <br /> t •: ii« •jvi y!im*^Ti- '''.'l{- M |[« ,1 •-•Vft<br /> <br /> <br /> <br /> <br /> B I M — i ^ l — J B « M I iirwiiM mil III •III •at.-^uWMim<br /> Hinh 6. Phd phdt xg thu dugc khi mdy bay bay qua sdng (River)<br /> <br /> 36<br />  H6i nghi Khoa hoc ky niem 35 ndm Vien Khoa hoc vd Cong nghe Viet Nam - Hd Noi 10-2010<br /> <br /> <br /> <br /> -—<br /> J J B / U<br /> 3 "*<br /> A ..P C D I E R H r M C .;<br /> . . ' . . . 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