Ky v^u Hdi thao ICT.rda'06 Proceedings of ICT.rda'06. Hanoi May. 20-21, 200f
XAY DlfNG MO HINH THONG KE CHO HE THONG NHAN DANG TRONG DAI QUAN TRAC KHONG LlTU "NHEBO - 55J6"
Building statistical models for recognition system in the sky surveillance radar "Nhebo-55J6"
Nguyen Phiing Bao, Nguyen Hoang Nguyen, Pham Thanh Giang, Nguyen Huy Hoang
Tdm tat
Tren ca sd phdn tich cdc tham sd chien ky thudt cua ddi quan trdc khdng lieu "Nhebo - 55J6" bdi bdo danh gid khd ndng thdng tin ciia ddi ndy theo quan diem phdn biet nhdn dgng. Tic dd de xudt phuang dn xdy dung md hinh thdng ke phuc vu muc dich phdn biet nhdn dgng muc lieu.
Tur kitda: phat hi$n trong rada, nhin dang trong rada, chan dung ra da, mo hinh thong ke.
Abstract
Based on analyzing technical and tactical specification of the sky surveillance radar
"Nhebo-S5J6", this paper examines information ability of the radar in term of recognition, then proposed a plan to set up a statistical model for the target recognition purpose.
Keywords: radar detection, radar recognition, radar portrait, statistical model.
l.DATVANDE
Mgt trong nhirng van de dau tien dat ra khi thiet ke mpt h | thong nhan d^ng la lya chpn khdng gian dau hifu va xay dyng md hinh thong ke cho cac doi tugng d n phan bi^t. Tuy theo tinh chat dSc diem cua timg ph- uong ti?n thu thap tin tiirc cung cac ldp doi t- ugng can phan biet ma tdn t^i nhieu phucmg an tiep c$n va each giai quyet van dl khac nhau. Sau day chung ta lan lugt xem xet trinh ty giai quylt van dl nay cho trudng hgp cu the vdi phuong tien thu thap tin tiirc la dai quan trie khdng luu 55J6 cdn doi tugng phan bi^t nhan d^ng la cac myc tieu bay.
2. Gidl THIEU CHUNG VE DAI QUAN TRAC KHONG LU*U 55J6
Dai quan trie khdng luu 55J6 thugc he Rada canh gidi, Nd cd chuc nang phat hien, bam bat cac myc tieu tren khong d tam xa, do dac toa dg khdng gian cua chiing (cy li R, phuong vi B va edc ta hoac dd cao c> \a
phan bi?t ta-dich. Nhung tham so chiln k;
thuat chii ylu ciia dai rada nay da dugc gid thifu chi tilt trong [7], d day chiing ta chi ta|
trung xem xet nhOng d^c tinh quan trpng c(
lien quan tdi kha nSng phan biet nh|n danj cua h^ thdng.
2.1. Tin hieu tham do
Tin hi?u thdm dd ciia 55J6 la diy xun|
diiu pha md Barker 13 vj tri phat dong bp vd cdng suSt SOO-dOOA'ff; dp rpng xun|
t^=13x3,3pj; dp rpng phd hifu dynj A/ = 300 kHz . Tan sd lap cua xung thSm dt cd thi chuyin doi giua 2 gia trj F„ = 8O//2 hoac F^j = 200//Z. Trong dd F,, diing kh phat hien eac muc tieu quy dao vu try cdn F^
sir dung d ehl dp chinh. Kit cau cua tuyei phat dam bao dp on djnh tan sd giira cac xunj rat cao (dp di tan tuong doi cd 3.10*). Ngoa ra he thdng cdn dam bao che dp thay ddi tai so sdng mang theo tirng chu ky lap, sd lugni
Ky yeu Hpi thao ICT.rda'06 Proceedings of lCT.rda'06. Hanoi May. 20-21.:
lam viec khdng cao lam (±10~*) tuy nhien sai lech nay dugc ty bii khir bang each siir dung chinh dao dong cua tuyen phat lam ngoai sai cho tuyen thu.
2.2. He thong anten
Thanh phan chinh la mgng anten kenh cir li; mgng anten thu kenh do cao; 6 anten phu trg (Al-5). Trong dd, quan trpng hon ca ddi vdi bai toan nhan dang la mang anten kenh cy li va anten phu A5. Khi hoat dpng h^ thdng anten thue hien quet canh sdng trong mat phang phuang vj vdi tdc dp 0 ^ = 3 6 ° / ^ (6vdng/phut) hoac Q„ = 18° / s (3 vdng/phiit).
Mgng anten kenh cir li cd nhiem vu phat va thu tin hieu vdi phan eye ngang. Sau day la cac tham sd ky thuat chii yeu ciia nd:
He so khuech dai: G = 800;
Dp rpng canh sdng trong mat phang phuang vj d muc 1/2 cdng suat: A0p - 3,5";
Dp rpng canh sdng trong mat phang gdc ta d mire 1/2 cdng suat: A©^ = 16°;
Hudng nhin ciia anten trong mat phang gdc ta: e = 0-rl6°;
Mire canh sdng phu: 18-20dB;
Gian dd hudng cua anten trong mat phan|
dirng khdng nhirng quyet djnh bdi phan bd bien dp - pha tren mat md ma cdn phy thupc vao dp cao h^ ciia tam diem dien tur anten so vdi mat dat. Neu viec trien khai anten dam bao cac yeu cau dat ra cho dai sdng met thi gian dd hudng se cd dang cosecan.
Anten phu A5 cd phan eye dirng, cau tao tir 8 cpt chan tu tich eye nOra bude sdng dat thang dimg, mdi cdt gdm 6 chan tii tich eye cimg ludi phan xa. Cac cdt chan tu nay bd tri phia sau be mat phan xa, giira cac chan tiir cua anten kenh cu li sao cho canh sdng tao ra cd hudng trimg vdi canh sdng chinh ciia anten kenh cy li. Nd dam bao phan bd bien dp - pha tren mat md anten cd dang d^c biet theo phuang thang dung va ddng deu theo phuang ngang. Nhd vay canh sdng ciia A5 gan gidng vdi canh sdng anten kenh cy li trong m§t
phing dumg cdn trong mat phang ngang s dp rpng Idm horn cd 2-3 lan.
2 J . He thong thu
He thdng thu cua 53J6 bao gdm: kenl li (kenh chinh), 6 kenh pnu (K1-K6), kenh di va 16 kenh do cao (aAl-aA16). Tat ca kenh dugc xay dyng theo sa dd sieu ngoai vdi mpt lan biln tan (tin sd trung i
f,g = 30MHz). Cac phan tu cimg chirc n;
cua tSt ca cac kenh cd cau tao gidng nhau.
tang dp nh?y may thu, trong he thdng an phi da dung hai tang khuech dai cao tan. Ti thu nhat la mach khuich dai dai rpng khc hifu chinh d^it ngay gan bd himg sdng ( anten. TSng thir hai bd tri trong xe thiit Day la mach khuich dai cao tan cd dp eh Ipc cao va kha nang hieu chinh tan sd tru tam tuy theo bang tan lam viec cua dai. \ each thiet ke nhu vay 55J6 dam bao dp ch Ipc cao theo tan sd, miirc tin hieu tham nh theo eac kenh khdng mong mudn dugc h che nhd viec sir dung thiet bj chgn Igc vdi c bd cdng hudng cd he sd pham chat cao va k nang dieu chinh tan sd cdng hudng b i phuang phap dien tir ciing cac bd trdn ki' vdng khuyen. De nang cao dai ddng, cac kei thu cua 55J6 sir dung rat nhilu chiing lo mach ty dieu khuich khac nhau. Chung da bao he sd khuech dai tuyen tinh trong Idioai bien doi 60dB. d day can luu y rSng cac mai ty dieu khuech, ty bii khu theo chu ky se gi sai lech cho chan dung rada va lam anh hudr xSu tdi chat lugng nhan dang muc tieu. E loai trCr anh hudng dd tin hieu phuc vu nha d^ng nen trich ra trudc khoi ty diiu khuec (tir dau ra cua m?ich khuich dai trung tAn c diiu chinh). Lya chpn phuang an nhu vay h thdng nhan dang cd c4u tao phirc tap han (d can phai xay dyng them cac sa do khuich di va nen tin hi?u) nhung chat lugng nhan dan se dugc nang len dang ke.
2.4. Nhirng tham so chien ky thuat cw ban Rada 55J6 dam bao ddng thdi do dac ci li, phuang vj, gdc ta (ho^c dg cao) cua mui tieu trong pham vi E = 0 - 1 6 ' . Viec sue s?ic
Al H6i thao ICT.rda'06
KyyeuHJ
theo phucmg vj thyc hien bing each quay anten vdi v$n toe 3 vdng/phiit hoac 6 vong/phiit. Sai so do toa dg muc tieu ciia dai 55J6 dugc dua ra trong Bang 1.
Bang 1. Sai so do toa do ciia dai 55J6
Proceedings of ICT.rda'06. Hanoi May. 20-21, 200
Cac tham s6 C y l i - a ^ , Phucmg vj - Op
D$cao - CT^
Sai s6 TBBP 500m
0,4°
850/n(^^200Arm;)
2"<E<16''
2000m (^>200/r/n;) e<2°
Dai 55J6 cd kha nang do toa dg muc tieu vdi dp chinh xac cao horn so vdi cac Rada canh gidi cung loai. Dieu nay dugc ly giai bdi hai yeu td sau. Thir nhdt, 55J6 diing tin hieu tham dd phuc tap vdi phd rgng. Thir hai, sy ty dpng hoa ehl dg thu nhan thdng tin cho phep lo^i trir sai so quan sat ciia trie thu khi do to^
dp myc tieu. Ngoai ra d n luu y rang sy phan x^ sdng tir m$t dat gay anh hudng dang ke tdi chat lugng kenh dp cao. 6 dp cao nhd (D > 200Km; e < 2°) sai sd nay cd gia trj qua Idn (2000m) nen trong thyc te ngudi ta xac djnh dp cao cac muc tieu bay thip bing each tinh dp cao iing vdi cy li phat hi?n eye dai ciia kenh cy li - phuong vj.
2.5. Hf thong tu dong xir ly tin tvc
Chirc nang ciia H? thong la thyc hien nhiem vy xir ly cdp 1 va cdp 2.
Qud trinh xir ly cdp J bao gdm cac thao tac sau:
• Phat hi?n tin hi?u phan xa tir muc tieu;
• Xac djnh to? dp muc tieu theo kit qua mdi chu ky quan sat;
• Lien ket dau hieu ta-djch vao cac diem dau phat hien dugc.
Xu ly cap 2 dugc tiln hanh vdi myc dich nang cao chat lugng tin tuc truyin di va giam tai cho trSc thii trong dieu ki?n quan sat phirc
tap. Npi dung chu ylu eiia qua trinh xir ly 1 tyr dgng hod qud trinh plidt liien, gdn ket v(
quy dao va bam muc tieu. 6 day viec xac djn va danh dau vet quy dao cua tirng muc tie dugc trSc thu thyc hien. Sau khi nhan dup thdng tin ve 2 diem dau dau tien thudc qu dao ciia mdt muc tieu nh4t djnh nao dd ma tinh chuyen dung se tiln hanh kit noi ea diem dau de ve ra dudng quy dao tuang irnj Vdi gia thiet la muc tieu chuyen dpng thin deu may tinh se tim toa dp diem dau trong eh ky quan sat tiep theo b5ng phuang phap ngo:
suy. Nhirng diem ngoai suy cua cac quy da bam cimg thdng sd eiia muc tieu (so thiir ty v dp cao) dugc hien thj tren man hinh Sii Ngoai ra thdng tin day dii ve mdi muc tieu c the gpi ra tren bang thdng so tuong irng (ba gdm cy li, phuang vj, gdc ta, dp cao va sd th ty eua muc tieu). May tinh chuyen dung ch phep ddng thdi bam tdi 30 myc tieu.
3. DANH GIA KHA NANG THONG TIN CUA DAI 55J6 THEO QUAN DIEM PHAN BIET NHAN DANG
Kha nang phan bi^t nhan dang doi tugng ci mpt h^ thdng quan trac vd tuyen di^n dut;
quyet djnh bdi lugng dau hi^u ed trong ci loai chan dung ma he thdng cd the cung ca|
Trudng hgp chung, tren ca sd tin hieu phan >
tir muc tieu ta cd the nhan dugc nhirng lo;
chan dung rada dien hinh sau [2,3,5,10]:
• Chan dung cdng suat;
• Chan dung thang giang;
• Chan dung tuong quan tan sd;
• Chan dung cdng hudng tan so;
• Chan dung phan eye
• Chan dung cy li;
• Chan dung anh;
• Chan dung Dopier (phd).
Chan dung cong suat bao gdm mpt g trj bien dp phirc ^ , vdi ky vpng toan h^
bang khdng (^ = 0). Nd dugc dSc trung b(
gia trj trung binh binh phucmg cd gia \T\ ga hai lan cdng suat tin hieu phan >
Ky ygu Hpi thao ICT.rda'06 Proceedings of ICT.rda'06. Hanoi May. 20-21. 20
( 4 ' = 20^). Nhu ta da biet cdng suat tin hieu phan xa a] ty le vdi dien tich tdn xg hiiu dung (DTTXHD) ciia muc tieu a „ , . Thong thudng muc tieu cang Idn thi DTTXHD cua nd cang Idn. Do dd tren ca sd cdng suat tin hieu phan xa cd the danh gia ve kich cd ciia muc tieu. Tuy nhien DTTXHD cd the thay doi tang giam bang nhieu giai phap ky thuat khac nhau nen neu chi diing mpt dau hieu la cong suat tin hieu phan xa thi khdng the khang djnh dugc ve kich cd thyc te cua myc tieu. Ddi vai ddi 55J6, khi siir dung chan dung cdng suat can tinh toan tdi dang gian dd hudng ciia anten, trong dd dac biet chii trpng tdi sy bien dang canh sdng do anh hudng cua tin hieu phan xa tir mat dat khi Rada quan sat vdi gdc ta nhd. Ngoai ra d khoang bude sdng 1,5m cung cSn luu y tdi tinh chat cdng hudng ciia cac phan tir ciia muc tieu cd kich thudc gan vdi gia trj bude sdng.
Chan dung thang giang la mdt tap hgp N gia tri bien dp phuc cua tin hieu phan xa thu dugc tai cac thdi diem khac nhau. O day khdng gian nhan dang chinh la thdi gian cdn sd lugng phan tir cua chan dung dugc chgn bang sd xung trong mdt chiim xung phan xa N = T^JT^ (r^, va T^-\lf^ la do rgng cua ehiim va chu ky lap xung tham dd). Tham sd ca ban cua chan dung thang giang la thdi gian tuomg quan hoac tuang irng tren mien tin sd do rgng phd thang giang. Nhirng tham sd nay ed lien quan tryc tiep tdi kich thudc theo chieu dai va chieu ngang cua muc tieu (kich thudc cang Idn thi thdi gian tuong quan cang nhd va phd tin hi|u phan xa cang rpng) ma khdng phu thudc nhieu vao cac phuang phap nguy trang be mat phan xa dang sir dyng trong thyc te. Ket qua khao sat cho thiy thai gian tuang quan ciia tin hieu phan xa la kha Idn: Tj = 250//w^ < 255 tuy theo kich thudc va dac tinh chuyen ddng cua muc tieu [3,6].
Xet vdi ddi 55J6 ta cd:
r^, =A0p/Q„=97(194)m5«-Cj, vi vay lugng thdng tin cd trong chan dung thang giang la rat it va khdng nen sir dung loai
chan dung nay.
Chan dung tirong quan tan so la m t?p hgp N gia trj bien dp phuc cua tin hi phan xa thu dugc tai mgt thdi diem tren c tin sd khac nhau 4, • i,(.t,f,y, n = \,N.
day khdng gian nhan dang la tin sd va i dugc danh gia qua ham tucmg quan tdn s Trong dd tham so quan trgng la khodng tdn.
tiroTtg quan cd gia trj ty le nghjch vdi dd d hu&ng tdm Ar^, ciia muc tieu. De danh g dugc khoang tin sd tuang quan can phai th(
man dieu kien /„ »A/L, (/o "tan sd sdr mang tin hieu tham dd). Nhu vay, neu mi tieu cd do dai hudng tam Ar„, =(1-100)/
thi khoang tin sd tuong quan se thay di trong khoang Ar„, =(150-1,5) MHz. Di 55J6 boat ddng d /^ = 200MHz nen khdr dam bao dieu kien sir dung loai chan dun nay.
Chan dung cong hvong tan so la mi tap hgp cac gia trj bien dg phirc cua tin hie phan xa thu dugc tai mgt thdi diem tren A tan sd khac nhau nam trong khoang the hie tinh chat cpng hudng cua muc tieu. Nd man thdng tin ve sy bien ddi tinh chit phan xa eii muc tieu theo bude sdng. Ddi 55J6 lam viec . dai sdng met (viing the hien rd net chan dun cdng hudng tin so), cd kha nang chuyin ti vdi nhjp dp bing chu ky lap ciia xung thar dd, so lugng gia trj tin so la 6. Nhu vay v nguyen tic ta cd thi nhan dugc chan dun' cpng hudng tin so vdi 6 phin tu trong md chan dung. Sy thSng giang giua cac phan ti cd the bd qua do thai gian tuang quan cii;
muc tieu Idn hon nhieu so vdi chu ky lap cu;
tin hi$u tham dd. Tuy nhien do dai biin dd cua tin so la nhd (<10%) nen lugng thdng tii phyc vy nh$n dang trong chan dung cpni hudng tin so la khong 1dm.
Chan dung phan cue bao gdm 4 gia tr bien dp phirc (A^ = 4) tuong umg vdi 2 vectc phan eye vudng gdc cua tin hieu phan xa kh tin hieu tham dd dugc phat tren 2 mat phing phan eye tryc giao. Chan dung phan eye mang thdng tin ve hinh dgng ya vj tri tuang ddi cua myc tieu trong mt phang phan eye. Day la
, HAi thao ICT.rda'06 Proceedings of ICT.rda'06. Hanoi May. 20-21, 2006
mOt trong nhihig dau hi?u nhan d?mg kha on djnh d6i vcfi nhieu chiing loai muc tieu thudng gjp. De d?t dugc lugng thong tin Idn nhat trong chan dung phan eye cin dam bao viec thu phat tin hi?u tren ca hai mSt phing phan eye vudng goc nhau. Doi vdi ddi 55J6 anten thu phat kenh cy li (kenh chinh) deu cd phdn cue ngang, rieng anten thu A5 cua kenh phu K5 lai CO phdn cue dimg. Nhu vay, tren co sd tin hi?u thu dugc ciia kenh chinh va kenh K5 ta chi CO the nhan dugc chan dung phan eye khong diy du. Tuy nhien do tinh chat on djnh ciia diu hi?u trong chan dung phan eye nen ta sir dyng loai chan dung nay vao myc dich nh?n d?ng la cin thiet. Khi sir dung chan dung nay cin phai luu y nhCi-ng ylu td sau:
Trong chan dung phan eye nhan dugc chi ton tai hai phin tir the hien tieh chat phan xa ciia myc tieu khi bj chieu xa bdi sdng tham dd CO phan eye ngang;
Anten kenh chinh va kenh phu K5 tuy ed cimg hudng nhung tham sd eua chiing la khong giong nhau (so vdi kenh cy li h? sd djnh hudng ciia K5 nhd han cd 2,5-3 lan) nhu v^y bien dp cac thanh phan phan eye vudng gdc se khac nhau tir 1,58-1,73 lan.
Bude sdng ciia 55J6 cd gia trj khdng khac nhieu so vdi vdi kich thudc cua cae phan tir phan X? tren bl m^t myc tieu. Nhu vay trong nhieu trudng hgp ed kha nang xay ra hien tugng cpng hudng.
Chan dung cur Ii la mpt tap hgp cac gia trj bien dp phuc cua tin hifu phan xa
i,„ = 4(/,);« = 1, ^ tuong ung vdi N phan tir phan giai ciia dai rada theo cy li. Siir dung chan dung cy li ddi hdi dp phan giai theo cy li phai nhd hon nhieu lin dp dai hudng tam Ar^, ciia myc tieu. Theo yeu clu nay thi dp phan giai theo cy li ciia dai 55J6 la kha Idn (cd 500m) nen viec nhan dang theo chan dung cy li la khong c6 y nghTa.
Chan dung anh la mpt tap hgp cac gia trj bien dp phiire cua tin hi?u phan xa tuomg iimg vdi cac phan tii phan giai cua dai rada theo mgt gdc quan sat nao dd. Chan dung anh mang thong tin ve DTTXHD ciia muc tieu
tren cae gdc phan giai tuong iing. Cung nhi da sd cac dai quan trie khdng luu khac, di rgng canh sdng trong mat phang phucmg v ciia Rada 55J6 la kha Idn. Tai cy li quan sa thdng thudng vife dam bao dp phan giai cli thiet cho chan dung anh la khdng the.
Chan dung Dopier la tap hgp N gia tr bien dg phuc ciia tin hi^u phan x^ irng vdi N phan tir phan giai ciia dai rada theo tan s(
<^^(F^);n-\,N. Tren ca sd chan dun]
Dopier ta ed the thyc hi^n nhan d?ing theo si the hien hi^u img dieu che quay ciia dpng ct ma myc tieu sir dung [1,5,10]. Dieu ki^n eai cho sy tdn tai hi^u ung dieu che quay la [1]:
-k>K. 4 ^
' N h a y / > / ^ , = cN
(1) Trong dd: X; / - bude sdng va tan s<
eua tin hi?u tham dd; R„i', N - ban kinh v;
so canh ddng co eua myc tieu; A,^„,; /„,, - gi;
trj tdi han ciia bude sdng va tan sd tin hi?i tham dd dam bao sy ton tai hi?u iirng dieu ch quay.
Xet tai dai sdng ciia dai 55J6 (X = 1,5m thi diiu kifn (1) dap iirng doi vdi kha nhili chiing lo^i myc tieu khac nhau. Vi vay ta ci thi dimg chan dung Dopier dl phan bi?t cai ldp myc tieu theo dang dpng ca ma nd si dyng. Ve nguyen tic, miirc dp chi tilt cua chai dung Dopier quylt djnh bdi dp phan giai thei tin so. D I nang cao dp phan giai nay cin thy hien tich luy cac xung nh$n dugc trong toai bp thdi gian quan sat. Hi?n tgi trong ddi 55Ji viec xu ly tuong can khdng dugc thyc hi?n Tuy nhien, do cac xung tham dd dugc phat d la dong bg vdi dp on djnh tin so cao nen t hoan toan cd thi xay dyng them them bp tici luy tuong can cho dai, thdi gian tich luy biuj chinh dp rpng cua chum xung phan xa:
T = — - \\94ms khi Q^ =12," Is Ulms khiQ=36°ls . (2) Trong dd: A0p = 3,5° - dp rpng canl sdng anten kenh cy li trong mSt phing phuoni
vi
Ky ygu Hpi thao ICT.rda'06 Proceedings of ICT.rda'06. Hanoi May. 20-21
Khi dd chan dung phd dugc tao ra bing each diing biln ddi Fourier nhanh (FFT) vdi sd diem rdi rac tuomg irng vdi s6 xung hieu qua trong chiim:
N,„=L=- A0„F
n.
(3)Trong dd: L -so xung trong chum; F^
- tan sd lap ciia xung tham dd.
Tir day ta xac djnh dugc do rgng phd hieu dung cua mdi bg Igc FFT theo cdng thirc:
AF = - ^ . (4) N. FFT
Tren Bang 2 la sd dilm va gia trj AF cua mdi bd Igc FFT umg vdi cac tham s6 khac nhau trong che do quan sat cua dai 55J6.
Ngoai ra can luu y rang thanh phin pho iing vdi dudng bao tin hieu phan xa cd do rpng Idn hon dang ke so vdi tin so lap ciia xung tham dd. Do dd trong chan dung phd se tdn tai hien tugng chdng phd giira cac thanh phan nam each nhau mgt khoang bang mpt so nguyen lan tan sd xung lap.
Bang 2. So diem FFT vi gia tri dai thong ciia cac hg IQC FFT 6avc lira chon trong cac
che do quan sat ciia dai 55J6
\N,„//^[HZ])
^ " ^ ^ \ . " "
^ ^ ^ ^
200//Z 80//Z
36'Is
16/12,5 8/10
18"/5
32/6,25 16/5 Nhu vay dai 55J6 cho phep nhan dugc cac dang chan dung mdt chieu sau:
1. Chan dung cong suat;
2. Chan dung phan eye;
3. Chan dung Dopier.
Cac dang chan dung rada mpt chieu tren day cd the tao ra sau mdt chu ky quan sat muc tieu. Chung cd the sir dung rieng re hoat ket hgp chung thanh mgt chan dung da chieu duy nhit: chan dung piidn circ - tdn sd (Dopier)) -
cdng sudt. Ngoai ra dl ting cudng thdng tin nhan dang cdn cd the kit h.
dung nhung ddu hieu quy dao ciia muc ti dSy tham so mang tin thi hien a do cao v tdc chuyin dgng ciia muc tieu. Trong^ d dp muc tieu nim trong cac gdi tin chuan dugc sau mdi chu ky quan sat con va chuyin ddng chi cd thi tinh ra sau 2-3 cl quan sat ddi vdi muc tieu da dugc bam.
4. XAY DlTNG MO HINH THONG Kl 4.1. Ve mo hinh thong ke cua chan dun
da mot chieu
Chan dung rada mdt chieu bit ky cc bieu dien dudi dang tap hgp cac bien dp | ciia tin hieu phan xa ^ = {^i;42;--4«'-•••
ung vdi N phin tu phan giai trong kl gian nhan dang tuomg irng [3,4,5]. Tru hgp khdng cd myc tieu, trong chan dung r chi tdn tai thanh phan cua nhieu tap:
Trudng hgp tdn tai myc tieu thudc ldp nao dd (^ = 1 -i-M ; M - so ldp muc tieu) chan dung se la tdng hai thanh ph
^ = ^ / + ^ * . trong
^k =feu;^2.i;---^,.*;---4v.i} -thanh phin hi?u phan x?. Neu cd thi coi ring cac phin ciia chan dung cd phan bo chuin thi dac ti thong ke ciia nd phan anh trpn ven trong tre ma tran tuong quan R = ^^* (trong dd hi$u "*" thi hien ma tran lien hgp phirc; d
" " la ky hieu lay trung binh thong ke). K do md hinh thong ke ciia cac Idp doi tugi cin phan bift cd the bilu dien dudi dang ha mat do xac xuat sau[3,4,5,8]:
Trudng hgp ton tai myc tieu thugc Idp k
Trudng hgp chi cd nhieu tap:
yt„ Hfii thao ICT.rda'06 Proceedings of ICT.rda'06. Hanoi May 20-21, 2006
Trong dd: d e t - ky hieu djnh thuc ma tr$n;
Trudng hgp cac phan tOr cua chan dung Ichdng tuong quan thi
R.=||dl = ||^-.*C|| = K*5,„„,|;(6,a)
Trong dd:
' - • / = 0'5|4„,
alj, = 0,5^„j,\ - phuang sai eua phin tir thu m va n trong chan dung Dopier; h^„,„^ - ky hieu ham Kroneker.
Thay (6) vao (5) ta nhan dugc:
^fe)=n
4t(oL +o;^) exp 2(o;, +<.,) (7,a)Pf{\)-t\
- ' 47t aif exp %.
,2 \
2o -.} ) (7.b) Ma tr^n tuong quan cua chan dung rada phy thudc vao tinh chat phan x? cua myc tieu trong khdng gian nhan dang tuong ung.
Nhu-ng tinh chit phan xa nay quylt djnh bdi cac yeu to sau: kich thudc, hinh dang, tinh vung chic ciia hinh dang, d§c dilm kit d u ciia myc tieu va dang ddng co ma nd sir dyng [1,5,8,9]. Do chinh la nhung diu hieu mang thdng tin vl chung loai myc tieu. Vi vay ngudi ta thudng bilu dien chimg dudi dang ma tr?n tham sd thdng tin 0.„f. Ngoai ra ma tr^n nay cdn phu thpc vao mdt loat cac tham sd. Nhirng tham sd nay khdng mang hoac cd the mang rit It thdng tin vl chiing loai muc tieu nhung ylu td quan trpng la chiing ed anh hudng tdi eac tham so trong ham phan bd ciia chan dung [2,4]. Vi du nhu hudng myc tieu so vdi dai rada khdng mang thdng tin ve chimg lo^i myc tieu nhung lai cd anh hudng rd net tdi tham so phan bo ciia chan dung cdng suit va chan dung phan eye DTTXHD cua muc tieu eune nhu hieu imp khir nhan nrr riia nn
phu thudc dang kl vao gdc nhin). Cd thi bilu dien cac tham so nay bing ma tran tham so it thdng tin Q^.. Trong dd ta tach rieng thanh phan tham sd it thdng tin ludn tdn tai vdi mpi loai chan dung dd la ma tran tuong quan eiia chan dung nhilu tap R^ . Tren Bang 3 gidi thieu nhirng tham so thdng tin va tham sd it thdng tin ciia cae chan dung rada mpt chieu da dugc lya chgn cho dai 55J6.
Bang 3. Tham so thong tin va tham so it thong tin ciia cac chan dung rada trong dai 55J6
Loai chan dung
Dopier
Phan cue Cong
suat
Cac tham so ciia chan dung Thamsd
thong tin
Dang dong
CO
Hinh dang myc tieu DTTXHD cua myc tieu
Tham so it thong tin 0 ^ .
Chi dp hoat dpng cua dpng
ca.
Hudng muc tieu so vdi d^i rada.
Hudng muc tieu so vdi d^i rada.
4.2. Mo hinh thong ke ciia chan dung Dopier Chan dung Dopier dugc t^o ra dudi dang tap hgp eac tin hipu ngau nhien
^ = |4,;42;--4«;--^^„J tren N^„ diu ra eiia eac bg Igc FFT dai hep. Do mdi thanh phan phd trong tin hieu phan xa thudng dugc tao ra bdi mpt sd lugng Idn eac phan tir phan xa eye bd, ddng thdi mdi thanh phan nay ciing chju tac ddng ciia rat nhieu eac yeu to ngau nhien dgc lap vdi nhau nen cae phin tir trong chan dung Dopier cd the coi la biln ddi theo quy luat phan bd chuin va khdng phy thupc lin nhau [1,2,3]. Nhu v|y dSc trung tien nghiem ciia chan dung Dopier chinh la phuang sai ciia tit ea cac phan tOr phan giai trong nd: a^; n = 1 ^ N^^^ . Nhfl-ng gia trj nay phy thupc vao dang dpng co eiing ehl dp lam viec eiia ddng co dd. Tnrdng hgp khdng cd thdng tin chinh xac ve cae gia trj
al;n = \'^Nr^r. ta cd thi bieu dien chime
Ky ylu Hpi thao ICT.rda'06 Proceedings of lCT.rda'06. Hanoi May. 20-2
mpt each gan dung, thdng dung nhit la dung ham epxilon [3,6]:
«J-^ = 01*^^/^ expi
'%
(-P.-N)-
(8)Trong do: a^, Pj - cac he sd ; <s\. - A phuong sai ciia thanh phan than trong chan dung dopier ddi vdi muc tieu thupc ldp k (A: = 1 ^ M ; Af - so Idp muc tieu).
43. Mo hinh thong ke cua chan dung phan cue
Trong h? vector tuyln tinh co sd chan dimg phan eye khdng day dii nhan dugc trong dai 55J6 CO the bieu diln dudi dang:
^=fe,.^,r={u.ur-
Trong dd, chi so thii nhat ky hieu phan eye ciia tin hifu tham dd, chi sd thu hai - phan eye ciia tin hieu thu dugc (H - phan eye ngang; V - phan eye diimg).
Doi vdi da sd cac chiing loai myc tieu bay, ma tran ^ dugc t^o nen bdi cac tin hifu phan xa tir nhieu phin tir phan x? cue bg [3,5,61. Vi
ly do do nen quy luat phan bd cua cac phan tiir tr(Hig chan dimg phan eye cd the quy vl dang chuin (5). Diem khac biet so vdi chan dung Dopier la cac phin tii cua chan dung phan cue cd moi tuong quan vdi nhau, ma tr^ tuong quan ciia no dugc viet dudi d^g:
RHK.IhRIHK
(9)Trong do: r^, cp„, la he sd tuong quan va dp If ch pha trung binh gi&a cac phan tiir thu m va thiir n trong chan dung phan cue.
D|ic tinh thong ke ciia ma tran phan eye phu thupc vao hinh dang ciia muc tieu cimg vi tri tuong doi cua nd so vdi dai rada.
4.4. Mo hinh thong ke ciia chan dung cong suit
Chan dung cdng suit thi hien trong bien dp ciia tin hieu phan xa tir muc tieu. Dac tinh thong ke ciia chan dung nay chinh la phuong sai tin hieu phan xa rs\. Nd phu thgc vao:
DTTXHD cua muc tieu CT„, ; Cac tham sd co dinh cua dai rada suit phat, dang gian dd hudng, he sd k d^i cua tuyen thu...);
Cy li ciia muc tieu va vi tri tuong d- nd so vdi dai rada.
Dl md ta cac tinh chit thong ke cua tin phan xa tir myc tieu ngudi ta thudng kifu md hinh tliong ke do Swerling de xu Phan bd Swerling-1 (SW-1):
;'(<J.<J.,)= exp(--^); ( Phan bo Swerling-2 (SW-2):
4a
/'(«J.<'«) =
(a,,)^
exp( ),
CT-,
(
Trong dd: a - gia trj tire thdi DTTXHD ddi vdi myc tieu dang xet.
Phan bo SW-1 thudng diing cho cac i tieu bay cd cau tao tiir nhieu phan tu phar vdi cudng dp khdng khac biet Idn (myc d^g tap hgp cac diem chdi). Nlu muc \ chi bao gdm mpt phin tir phan xai (1 di choi) hoac mpt phin tu phan xsi ciia nd cuong dp vugt rat nhieu so vdi cac phin khac thi dimg phan bo SW-2. Truang i.
diing phan bd SW-1, tin hifu phan xa dugc ra tir nhieu cac diem chdi dpc lap nen tl djnh ly Liapunov ta cd thi coi ring quy li biln doi dudmg bao tin hi
M{t) = X„{t) + iY„{t) la qua trinh nglu nhi vdi phan bd chuan:
^^^>=(2;o^H-|^»'
(12)
Trong do: M = {M„A/,,....,A/J.nia tra cac gia trj rdi rac cua M{I) tai cae thdi dili
x = ( * - 0 7 ^ k,l=i2...L R^=M,M;=2olR„[(k-l)T^] . phan t
trong ma tran tuong quan cua dudng bao tii hifu phan xa \\R^\\ (dugc tinh theo gia trj ban tuong quan cho dudng bao tin hieu phan x;
H6i thto ICT.rda'06 Proceedings of lCT.rda'06. Hanoi May. 20-21, 2006
i?«(t)); ||e«i=F*/ir - ™ ^^" "ghjch dao cua matron |/?4,||.
Trudng hgp dung phan bo SW-2 thi X (0 ^^ ^m^) '^^ P'^^" ^ '^^'^ t^l-
Chan dung cdng suit cd thi su dyng ddc l|ip ho?ic v|in dung ket hgp trong nhieu loai chan dung rada khac mdt each phiire tap hon.
Vi du: cdng suit ciia thanh phin than muc tieu ciia chan dung Dopier, cdng suat cua thanh phin ddng phuang trong chan dung phan eye.
4.5. Mo hinh thong ke cua chan dung rada da chieu
Chan dung rada G chieu cd the bieu dien dudi dang rdi rac sau [1,9,10]:
Trong dd:
<i..2;°\U^'"i."i ^\^N,;m„n, = \^N - phuang sai ciia cae thanh phan tuong ilmj trong chan dung; r®„2,,„2 - hf sd tuong quai giira cae thanh phin tin hifu cd phan cy(
vudng gdc vdi nhau; (p,,j,2^i„2 - ^9 '^^h ph;
trung binh giCJa cac thanh phan tin hifu c(
phan eye vudng gdc vdi nhau.
S lpn,,...ii^.../if; I Sii,....»^...iV: I ^ Fv Tn nj-.-n^'
(13)
Trong dd: n^ =\-!r N^ - cac gia trj rdi rac theo tryc toa dp x^; N^ = X^ Ihx^ - so lugng gia trj rdi rac theo eac true toa dg x^
(g = 1 ^ G); A'^, 5.x^ - dp dai va gia trj bude lugng tir theo tryc to^ dg x^.
Coi ring chan dung cdng suat la thanh phan khdng the thieu dugc trong chan dung phan eye thi chan dung phan eye - phd - cdng suit ma ta ed the nhan dugc trong dai 55J6 cd the coi la loai chan dung 2 chieu (G = 2) vdi chilu thu nhit ( J:, ) la gdc hudng ciia hf thdng anten phan eye tuyln tinh © cdn chieu thii hai (^2) la tin sd F . Buoc lugng tu va sd phan tiir theo cac true x^ va Xj la:
5x, =90"; n,=\^N-N.= 180 90 2;
& t 2 = A ^ =
N.
•,n,=\^N-N = N,
Trudng hgp chung cac phin tiir trong ma tran tuong quan ciia chan dung phan eye - phd - cdng suit cd thi viet dudi dang:
^-1-2.1,2 - 2 o , „ j - a . i . j •^^,.i..2) •'•-
m, \.n^=lN^.y = \,2, (14)
Gia trj eua (p„, „2,,i.-2 P^V thugc vao hinl dang, gdc hudng va vat lif u che t^o myc tieu Dpi vdi cae muc tieu thyc tl gia trj nay bier ddi nglu nhien tir theo chu ky quan sat. Vi vaj vif c bii khiir dg If ch pha dugc tiln hanh tronj qua trinh xiir ly chan dung phan eye.
Cin luu y ring, vdi da so cac myc tiei bay thi cdng suit tin hieu phan xa tir thanl phan phan eye ngang - dong phuang ed gia tr Idn han dang ke so vdi cdng suat tin hifi phan xa tir thanh phin dirng - cheo. Ngoai n bl mat phan xa hifu dyng eua eac phan ti quay cung nhd han rit nhilu so vdi be m$
phan xa hifu dyng etia than myc tieu. Chinh v v^y ma modul cua cac thanh phan phan eye diimg gay ra bdi hifn tugng dieu che guaj trong chan dung phan eye - phd - cdng suat I9 cang nhd. Ngoai ra, anten A5 eiia dai 55J6 cc hf sd khuich d?i nhd hon hf so khuich da ciia anten chinh ed 2,5-3 lin trong khi eai ting thu noi vdi chung cd d u tao hoin toar giong nhau. Vi v?y c^e phin tu iing vdi thanl phin phan eye diimg, gayra bdi hifn tugnj diiu chi quay sS bj nhilu manh va cho i thdng tin. Vi vay khi thyc hifn nh$n d^nj trong dai 55J6 ta se siir dyng chan dung phdr cue - phd - cdng sudt khdng day du. Char dung nay bao gdm:
Vdi thdnh phdn phdn cue ngang: diinj toan bg chan dung phd vdi phan tir phan xa ti than va cac phin tii gay ra do hifn tugng diei chi quay;
Vai thdnh phdn phdn cue dirng: chi diinj phin tir phan xa tir than myc tieu.
5. KET LUAN
Vife xay dyng md hinh thong ke cae myc tieu bay doi vdi hf thdng (luan trie 55J6 \i mgt trong nhung veu eau can ohai cd ciia dt
Ky y^u Hpi thao ICT.rda'06 Proceedings of ICT.rda'06. Hanoi May. 20- tai c i p Nha nude KC.01.23. Cac ket qua
nghien ciru da dugc chiimg minh bing thyc nghifm trong de tai. San pham dugc siir dyng lam CO sd d l xay dyng "thu vifn difn tu" chan dung cac mlu muc tieu l i p dat trong thiit bj phan bift - nhan dang cua 55J6.
Tai lif u tham khao
1. Y.D. Shirman: "Computer Simulation o f Aerial Target Radar - Scattering, Recognition, Detection and Tracking". Artech House, Inc.
Boston - London, 2002.
2. C P . refierep, C M . KOCTPOMHUKHH:
"CocTOflHHe H nepcneKTHBu BHeApeHwi cHcreM pacnosHasaHiu o6i>eKTOB a PJIC o63opa H TOMHoro HSMepeHwi KoopAHHar".
MejKdyHapodHOH HayiHO-mexHUuecKca KOHipepeHiiUH Mikon, 2002.
3. A. E. OxpHMeHKo: "OCHOBU pazoiojioKauHH H
paoHoaneiopoHHa)! 6opb6a". BoeHHsoar, 1983.
4. Hryen Xoanr Hryen: "CmpyicmypHO- napoMempuHecKcm adanmaifm peuiaioiueeo npaeuna cucmeMbi pacnomaeoHWi - IOM^XHWI".
JJjiKcepama na coucxaHHe yneHOH crencHH KaHiiHaaTa TexHHMecKHx nayic, MHHCK, 2003.
5. B.r. He6a6HH, B.B. Cepreea: "Memodbi u mexHwca paduonoKoifuoHHoeo pacnosHaaaHu/i".
M.: PaoHO H CB5Di>, 1984.
6. SI.J1, UliipMaH, KD.H. Jloces, H.H. MHHCPBHH,
C.B. MOCKBHTMH, JI.C. JICBHeHKO, C A .
fopUDCOB, Jin. JleXOBHUKHii:
"PadiunneianpoHHbie cucmeMbi". MocKsa AO
« M A K B H 0 > , 1998.
7. B.H. KapjcucoBa, JI.n. SirrbKOB, A.B. CTaHKeBHH,
"TpexKO(^)duHamHax paduonoKotfuoHHOJi cmaMipa 55)K6". MHHCK, 2004.
8. il.fl. lIlHpMaH, C A . FopiuKOB, r.fl. EpaTHeHKO, C.n. JlemeHKO: ^'Paduo/iOKoifuoHHoe pacncaHoeoHue". XapbKOB, 1994.
9. ^.JI,. LIlHpMaH, C A ropuncoB, TJl EparHeHKo, C.n. JleuteHKO, B.M. OpneuKo: ''Memnbt pawojioKauHOHHoro pacnosHasaHiu H HX MOAennpoBaHHe". Vcnexu coepeMeHHoU paduo3neianpoHUKU,BbatycKUl, 2000.
10. Nguyin Phiing B4o, Nguyin Hoang Nguyen,
"Phuong an tSng lugng thong tin phuc vy nhan d9ng cho cac d^i rada thim do bdng each xay dyng mo hinh thong ke thich nghi va kit hgp tin tire tir nhilu loai chan dung rada mpt chieu". Hdi thdo khoa hpc qudc gia lan thic hai ve Nghien curu phdt trien vd ung dung cdng ngh^ thdng tin vd truyin thdng ICT.rda '04, Ha nfi, 2004.
Ve cac tac gia:
Nguyen Phung Bio. T(
trudng Ra da Kiev (Lien 1982. Bao vf luan an 1999 vl phat hien phui bay CO diu vet ra da HVKTQS. Hien la Chi bp mon CNDT, Khoa HVKTQS.
LTnh vyc nghien ctiru: k^ thuat va cong nghe E-mail: nguvenphunpbao(aivahoo.com
Nguyen Hoang Nguyei nghif p trudng Ten lira PK (Li6n x6) nam 1991, bao ^ an Tiln s^ vl vin de xu 1) dang tin hieu va muc tiei tai truong 'Tdng hpp qui Belarus vl tin hpc va V nam 2003. Hien la Phd C mon CNDT, Khoa V HVKTQS.
Linh vyc nghien eihi: ky thu^t va cong nghe ra Email: npuvenhn2002(a).vahoo.com
Pham Thanh Giang.
nghif p tnrdng ra da Kiev ( x6 cu) nam 1989. Hien la Phong nghien ciiu ra da ' KTQS PK-KQ. Nghien sinh thufc TTKHKT& CN
LTnh vyc nghien curu: K.S thuat va cong nghf ra Email: phanmthanhpiangCaivahoo.com
NguySn Huy Hoang.
nghifp Hpc vien KT nam 1986. Hi?nia Phot Bf mdn CSKTVT- Kl VTDT-Hpc vien KTQ Nghien curu sinh thu Hpc vifn KTQS.
LTnh vuc nghien cim: I thuat va cong nghe ra da.
