Dab tsi yog peb hom polarization sib txawv ntawm SAR?

1. SAR yog dab tsipolarization?
Polarization: H kab rov tav polarization; V ntsug polarization, uas yog, kev co kev taw qhia ntawm electromagnetic teb. Thaum lub satellite xa cov teeb liab mus rau hauv av, kev co kev taw qhia ntawm lub xov tooj cua yoj siv tau nyob rau hauv ntau txoj kev. Cov khoom siv tam sim no yog:

Kab rov tav polarization (H-kab rov tav): Kab rov tav polarization txhais tau hais tias thaum lub satellite xa cov teeb liab mus rau hauv av, kev co kev taw qhia ntawm nws lub xov tooj cua yoj yog kab rov tav. Vertical polarization (V- ntsug): Vertical polarization txhais tau hais tias thaum lub satellite xa cov teeb liab mus rau hauv av, kev co kev taw qhia ntawm nws lub xov tooj cua yoj yog ntsug.

Electromagnetic yoj kis tau tus mob yog muab faib ua kab rov tav nthwv dej (H) thiab ntsug nthwv dej (V), thiab kev txais tos kuj muab faib ua H thiab V. Lub radar system siv H thiab V linear polarization siv ob lub cim los sawv cev rau kev sib kis thiab txais polarization, yog li nws tuaj yeem muaj cov channel hauv qab no—HH, VV, HV, VH.

(1) HH - rau kab rov tav kis tau tus mob thiab kab rov tav txais tos

(2) VV - rau ntsug kis tau tus mob thiab ntsug txais tos

(3) HV - rau kab rov tav kis tau tus mob thiab ntsug txais tos

(4) VH - rau ntsug kis tau tus mob thiab kab rov tav txais tos

Thawj ob ntawm cov kev sib txuas ntawm cov polarization no yog hu ua cov polarization zoo sib xws vim qhov kev xa tawm thiab tau txais polarization yog tib yam. Ob qhov kev sib xyaw ua ke kawg yog hu ua cross polarizations vim qhov kev xa tawm thiab tau txais polarizations yog orthogonal rau ib leeg.

2. Dab tsi yog ib qho polarization, dual polarization, thiab tag nrho polarization hauv SAR?

Ib qho polarization yog hais txog (HH) lossis (VV), uas txhais tau hais tias (kab rov tav kis tau tus mob thiab txais tos kab rov tav) lossis (nruab kis tau tus mob thiab ntsug txais tos) (yog tias koj tab tom kawm txog thaj tsam ntawm huab cua radar, feem ntau yog (HH).)

Dual polarization hais txog kev ntxiv lwm hom polarization rau ib hom polarization, xws li (HH) kab rov tav kis tau tus mob thiab kab rov tav txais + (HV) kab rov tav kis tau tus mob thiab ntsug txais tos.

Tag nrho cov tshuab polarization yog qhov nyuaj tshaj plaws, yuav tsum muaj kev sib kis ntawm H thiab V, uas yog, plaub hom polarization ntawm (HH) (HV) (VV) (VH) muaj nyob rau tib lub sijhawm.

Radar systems tuaj yeem muaj ntau theem ntawm polarization complexity:

(1) Ib leeg polarization: HH; VV; HV; VH

(2)Dual polarization: HH+HV; VV+VH; HH+VV

(3) Plaub polarization: HH + VV + HV + VH

Orthogonal polarization (piv txwv li tag nrho polarization) radars siv plaub lub polarizations thiab ntsuas cov theem sib txawv ntawm cov channel thiab cov amplitude. Qee qhov dual-polarization radars kuj ntsuas cov theem sib txawv ntawm cov channel, vim tias theem no ua lub luag haujlwm tseem ceeb hauv kev rho tawm cov ntaub ntawv polarization.

Radar satellite imagery Nyob rau hauv cov nqe lus ntawm polarization, cov khoom sib txawv pom backscatter txawv polarization nthwv dej rau cov xwm txheej sib txawv polarization nthwv dej. Yog li ntawd, qhov chaw thaj chaw deb qhov chaw paub siv tau siv ntau lub bands kom nce cov ntaub ntawv, lossis siv cov polarizations sib txawv los txhim kho thiab txhim kho qhov tseeb ntawm kev txheeb xyuas lub hom phiaj.

3. Yuav ua li cas xaiv hom polarization ntawm SAR radar satellite?

Kev paub qhia tias:

Rau kev siv dej hiav txwv, HH polarization ntawm L band yog rhiab dua, thaum VV polarization ntawm C band zoo dua;

Rau cov nyom nyom thiab txoj kev qis, kab rov tav polarization ua rau cov khoom muaj qhov sib txawv ntau dua, yog li qhov chaw SAR siv rau kev kos duab hauv av siv kab rov tav polarization; rau thaj av uas muaj roughness ntau dua lub wavelength, tsis muaj kev hloov pauv hauv HH lossis VV.

Lub zog ncha ntawm tib yam khoom nyob rau hauv qhov sib txawv polarizations txawv, thiab cov duab lub suab kuj txawv, uas ua rau kom cov ntaub ntawv txheeb xyuas cov hom phiaj. Kev sib piv cov ntaub ntawv ntawm tib lub polarization (HH, VV) thiab cross-polarization (HV, VH) tuaj yeem ua rau cov ntaub ntawv radar duab zoo dua, thiab cov ntaub ntawv sib txawv ntawm cov polarization echoes ntawm cov nroj tsuag thiab lwm yam khoom sib txawv yog qhov rhiab tshaj qhov sib txawv ntawm sib txawv bands.
Yog li ntawd, nyob rau hauv kev siv tswv yim, qhov tsim nyog polarization hom tuaj yeem xaiv raws li qhov xav tau sib txawv, thiab kev siv ntau hom polarization yog qhov tsim nyog rau kev txhim kho qhov tseeb ntawm kev faib khoom.